PROJECT RAND: PRE-D-DAY ELECTRONIC RECONNAISSANCE OF THE SOVIET UNION AND SATELLITE NATIONS

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP89B00708R000500070002-6
• Release Decision: RIFPUB
• Original Classification: C
• Document Page Count: 90
• Document Creation Date: December 22, 2016
• Document Release Date: September 28, 2009
• Sequence Number: 2
• Publication Date: September 1, 1953
• Content Type: REPORT

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U. S. AIR FORCE
PROJECT RAND
RESEARCH MEMORANDUM
PRE-D-DAY ELECTRONIC RECONNAISSANCE OF THE
SOVIET UNION AND SATELLITE NATIONS (U)
R. C. Raymond
A. L. Hiebert
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ASTIA Document Number ATI 210795
1 September 1953 Copy No.
This material contains information affecting the national defense of the United States within
the meaning of the espionage laws, Title 18 U.S.C., Sacs. 793 and 794, the transmission or the
revelation of which in any manner to an unauthorized person is prohibited by law.
This is a working paper. Because it may be expanded, modified, or withdrawn
at any time, permission to quote or reproduce must be obtained from RAND.
The views, conclusions, and recommendations expressed herein do not neces-
sarily reflect the official views or policies of the United States Air Force.
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This research memorandum is essentially a status report of a RAND
study of electronic reconnaissance. It is intended to outline the
study, to give some conclusions -which have been reached, and to state
a number of problems which require farther effort. The.study reported
here deals only with peacetime, cold-war,'or pre-D-Day reconnaissance.
A companion study on the active war phase has been under way for some
time. It is planned eventually to relate these two studies and to devise
plans for well equipped organizations which can be deployed in peacetime
to meet cold war intelligence requirements-and expanded in wartime to
support an active war effort as completely as possible.
An. examination of the list of problems remaining in this study shows
that there are many aspects-of electronic reconnaissance which are not
well understood.' This situation arises from the fact that electronic
reconnaissance is a relatively new activity.which is only beginning to
demonstrate its intelligence potential, and from the fact that military
electronics has progressed so rapidly in the-last 20 years that electronic
reconnaissance is continually confronted with new technical problems.
At the same time, a comparison of the conclusions reached at this
point with the current equipments and organizational practices shows
that considerable knowledge about electronic reconnaissance exists which.
has not yet been effectively applied, be:ause of slow developments in
equipments and organizations.
Subsequent reports' covering individual aspects of this study and
changes in the outline will be issued as they are completed.
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PRE-D-DAY ELECTRONIC RECONNAISSANCE OF THE SOVIET UNION
I. Exeanples of intelligence which can be obtained through electronic
reconnaissance
A. Order of battle of troops equipped with electronic devices
B. Purpose of electronic devices in Soviet operations
C. Capability of electronic devices to meet requirements
D. Vulnerability of electronic weapon systems to countermeasures
E. Physical characteristics and limitations of electronic devices
F. Relationship of electronic devices to other devices in systems
G. Level of Soviet operational. readiness
H. Indication of enemy action and intentions
II. Description of electronic reconnaissance process
A. Detection of new or unusual signals (Pioneer)
B. Reception of data for analysis (Detail)
Co Analysis of received data (Interpretation)
1. Signal analysis
a. Frequency
b. Modulation type
co Modulation waveforms
Direction or location of transmitter
e. Signal strength
f. Scanning pattern
g. Polarization
h. Operating schedule
2. Intelligence analysis, using collateral data to interpret
signal characteristics in terms of desired intelligence
in part I.
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III. Geography and propagation
A. Map of Soviet-dominated territory showing expected Soviet elec-
tronic activities and areas in which reconnaissance activities
can be carried out without overflight of Soviet-dominated
territory
Propagation of radio signals
1. Frequency ranges
2. Propagation mechanisms
IV. Electronic reconnaissance systems without overflight
A. Intercept stations
1. Types and locations (vehicles)
a. Ground fixed
be Ground mobile
c. Aircraft
d. Missile
e. Free balloon
f. Large ship
g. Small ship or boat
he Agent
2. Equipments
a. Receivers for detection and reception, effect of frequency
be Antennas, D/F, etco,
c. Recorders, removal of human error, cooperation with analyzers
d. Indicators, need for human mechanics
Be Analysis facilities, locations
1. Signal analysis to yield measurable characteristics (II,C,l)
2. Intelligence analysis, using all forms of collateral data
a. Communications intelligence
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Co
Command of electronic reconnaissance effort
1.
Unified command at theater level
2.
Use of all intelligence forms in programming effort
3.
Dissemination of electronic intelligence
a. Classification as low as permitted by security
be Outputs
(1) Theater
(2) ZI
it.
Coordination of electronic reconnaissance with other collec-
tion efforts and augmentation of primary mission of
other collectors
D. Communications in electronic reconnaissance
1. Speed with security
2. Possible solutions
Overflight Systems
A. Manned aircraft
1. High-altitude mission
Coverage attainable - (R and D),Air Armies, training
be Data recovery - recording, transmission, repeater
Co Time of availability
d. Risk - political considerations at time of use
e. Excitation of defenses - related to type of information
sought
f. Resolving power required in equipment
2. Low-altitude missj--
(Repeat a. to f. above)
Be Guided missiles
(Repeat a. to f. above)
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C. Free balloons
(Repeat a. to f. above)
VI. Organization for electronic reconnaissance
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A. Introduction- integration of electronic reconnaissance program
into regular intelligence program without creation of a
"special" force
Be Organization to follow logically from systems re.4uirements
1. Need for other intelligence in direction of electronic
reconnaissance
2. Need for combined analysis centers including COMINT and
other collateral sources
Need for combined operations With other collection agencies
I. Need for rapid analysis and feedback to intercept stations
5. Need for laboratory and model shop facilities
VII. Problems for further investigation
A. Number of stations required
Be Requirements for equipments for receiving signals
1. For detection
2. For reception
C. Antenna requirements
D. Recording system requirements
E. Indicator requirements
F. Organization requirements
G. Analysis center requirements
H. Communication requirements
I. Force requirements for overflight operations
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When data obtained by electronic reconnaissance are properly ana-
lyzed along with information from other sources it is possible to develop
useful intelligence of many types, in addition to she obvious ECM re-
quirements. The best exploitation of this souse- of information depends
on proper detailed direction of the electronic reconnaissance effort and
on thorough coordination of this effort with other intelligence activities.
Electronic reconnaissance operations can be divided into three phases:
(1) detection, in which the radiations of interest are first located
roughly through use of wide open equipment of low resolution;
(2) reception, in which detailed observations are made of the
radiations of interest;
(3) analysis in which the received data are examined for signal
characteristics and compared with other types of data to
produce useful intelligence information.
Propagation of radio signals and geographic locations of possible sources
require that equipments for detection and reception be distributed widely
in ground stations, ships, aircraft, missiles, and other places. Data
from all the stations in each sector or theater must be collected rapidly
for analysis in conjunction with other intelligence at analysis centers.
When flight over the Soviet Union and its satellite nations is for-
bidden, there is an area in Russia and Siberia large enough for the develop-
ment, equipping, and training of a large force with a new weapon system,
completely protected from our external observation. Aga.ts within this
area might be-of sane help, but we are not now receiving this type of
information, and the total we may expect to receive is small. Nevertheless,
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many improvements are possible and a great deal of information can be
obtained without overflight.
The need for rapid analysis and the difficulties involved with a
large volume of secure communication call for the development of theater
analysis centers and theater control centers. These centers would'direct
the work of all facilities in each theater and analyze the data to pro-
duce results useful at theater level. This would reduce the amount of
high speed communication needed from the theaters to the United States.
All types of data, including communication intelligence, should be ex-
ploited in these centers.
All types of intercept stations are capable of unique contributions
to the total effort. All stations within each theater should be brought
under control of a theater control center for coordinated operations with
each other and with other intelligence collection activities. Develop-
ment of station types most useful for overflight should be carried out
now, and stations capable of overflight should be tested in non-overflight
operations so that they will be ready if overflight becomes possible.
Development times for many of these station types will be much longer
than the time in which the political situation can change to make them
useful.
If overflight becomes possible, it may be undertaken with manned
aircraft, missiles, or free balloons. Of these, manned aircraft could
be put into operation earliest, but the other types would also be needed
as there would be requirements both for sneak missions to observe t)%F,
situation without exciting the defense and for observable missions in
which the purpose would be to excite the defense and reveal its operations.
Overflight operations could fill a substantial gap in our present coverage.
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Improvement of the equipment and manpower of existing electronic
reconnaissance organizations, and their unification under proper command
in the theaters, together with good support from other intelligence
agencies, would probably yield quicker and better results than the
creation of another "special" force for the electronic reconnaissance
mission. Present organizations can be strengthened, faiocated somewhat,
integrated into properly coordinated intelligence activity, and provided
with the necessary flexibility to perform adequately at much less cost
than the creation of a new force of.equivalent capacity. Time would also
be saved in this way.
Rapid changes in enemy techniques demand a high degree of adaptability
in electronic reconnaissance equipment. This can be obtained by allocating
laboratory and model shop facilities to the organization and by liberal-
izing military procurement regulations in regard to small quantities of
specialized items, The present military research and development cycle
is far too long to meet the needs.
The problems which need further detailed investigation for the comple-
tion of the continuing study are summarized in the last section of this
report.
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PRE-D-DAY ELECTRONIC RECONNAISSANCE OF THE SOVIET UNION
AND SATELLITE NATIONS
I. EXAMPLES OF INTELLIGENCE WHICH CAN BE OBTARM THROUGH ELECTRONIC
The term electronic reconnaissance will be used here to denote all
activity devoted to detection, reception, and analysis of radio signals
used by an enemy or potential enemy which cannot be reduced to literal
text. Electronic reconnaissance complements communication intelligence
activity by working with enemy radio signals which are not used for
communication. Electronic reconnaissance originated during'World War II
with the need for information which could be used in devising and applying
electronic countermeasures against the growing use of electronic devices
in weapon systems. The intelligence potential of electronic reconnaissance
has now grown to a point where it exceeds that of many other intelligence
sources. Electronic reconnaissance is of prime importance in intelligence
needed for airborne operations. Haphasis on this function could well be
increased because of its great information'gathering ability and the ex-
panding use by the enemy of electronics in weapon systems. As more elec-
tronic controls are used by the enemy, intercept equipments and methods
mast be improved to detect the existence and determine the threats of the
new radiating equipments. Some of the types of intelligence to which
electronic reconnaissance has made substantial contributions are listed:
A. Order of Battle of Troops Equipped with Electronic Devices
When lbrces are equipped with weapon systems involving electronic
devices such as radar, navigation systems, or remote control equipments,
in many cases the signals radiated by these devices during necessary
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training and maintenance activities can be received and used to identify
and locate the forces. For example, Soviet anti-aircraft units in Mat
Germany were for some time equipped with a type of radar fire-control
set which could be identified and located through its particular radia-
tions. Soviet GCI radar sets used for air defense can be identified
through their characteristic signals, and their locations can be determined
through electronic reconnaissance. Order of battle has long been recognized
as a very important intelligence item, and electronic reconnaissance can
contribute materially in many cases.
B. Purpose of ffiectronic Devices in Soviet Operations
The signals radiated by an electronic device will reveal to a
large extent the use to which the equipment is put. A thorough familiarity
with the military requirements of many types.of electronic devices will
often enable an analyst to determine the purpose of the equipment under
study from the characteristics of its radiations alone. In radar, for
example, a set with a high pulse-repetition frequency and short pulse
length is normally used for short-range work, such as fire control or
air interception, Whereas wide pulses at low pulse-repetition frequencies
are normally used for early warning. In other cases the coincident
observation of the electronic signals and other events provides the
necessary information. For example, the radio be= signals which were
used by the Luftwaffe in bombing England were observed before and during
the bombings, and their characteristics were compared with the results of
the bombings in determining the purpose of the system. A similar comparison
of signals from new Soviet navigation devices with training operations of
.Soviet forces observed by other methods may yield a better idea of the
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purpose of these new devices in the next few months. A comparison of
radar intercept data with fighter control communication might, for
example, enable a complete analysis of the purpose of GCI radar in
Soviet air defense..
C. Capability of Electronic Devices to Meet Requirements
When the purpose of an electronic device has been determined
through the process outlined above, the efficiency and capability with
which it meets its requirements can be determined by close observation
and complete analysis of its signal. In the case of an aircraft inter-
ception radar, for example, the minimum range at which a target vehicle
may be tracked can be ascertained to a large extent by the width of the
transmitted pulse, and the rate at which information is presented to the
observer can be obtained from the pulse rate and the scanning pattern of
the set. If in addition, other intelligence is available concerning
training exercises or flight patterns of Soviet aircraft, it may be
possible to determine other performance features of the set such as
maximum range, altitude limitations, effective angles, etc.
D. Vulnerability of Electronic Weapon Systems to Countermeasures
When the purpose and the capabilities of the electronic devices
used in an enemy weapon system have been evaluated to sane extent, it
becomes possible to combine the electronic reconnaissance data with the
other intelligence concerning the same system in order to select the
devices in the system.mos t vulnerable to countermeasures and to determine.
the countermeasure effort needed to reduce the effectiveness of the
weapon system to a desired degree. In an air defense systems for example,
it would be possible to evaluate the usefulness of countermeasures against
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the early warning radar, the GCI radar, the air interception radar, and
radar or other devices which might be used for fire control or missile
control.' This sort of evaluation was the first objective of electronic
reconnaissance, but it is no longer the only one of major importance.
Also, this objective can be met much more effectively by a well-rounded
intelligence program in which electronic reconnaissance data are combined
with data from other sources. It is imperative that the vulnerabilities
of enemy devices be determined in peacetime because of the time required
for development and production of the countermeasures equipments and the
training of necessary personnel.
E. Physical Characteristics and Limitations of Electronic Devices
A study of the characteristics of signals received in electronic
reconnaissance can often lead to a visualization of sane of the parts of
the radiating device and to the determination of its minimum values of
size and weight and minimum power requirements. These features can in
turn be used to facilitate collection of more information about the
device from photographic coverage or other sources. In World War II,
for example, a measurement of the horizontal pattern of the German early-
warning radar antenna was used by British analysts to predict that the
antenna structure should consist of six dipole elements in a certain
type of array.- This information enabled the British to secure and
identify photographs of the antenna structures involved.
F. Relations of Electronic Devices to Other Devices in Systems
When electronic reconnaissance shores the persistent co-location
of two different devices or is able to show correlation among two or more
different radiated signals, it is possible to analyze the relationship of
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the items in a single weapon system. If, for example, a certain type of
scanning radar and a certain type of fire-control radar are often associ-
ated, it is reasonable to conclude that the scanning set is a target-
acquisition device for the tracking set. If a pulsed transmission from
a Soviet aircraft is always preceded by a pulse transmission from a Soviet
ground station, it is probable that the two pulsed transmitters are associ-
ated in a system for navigation, fire control, or identification purposes.
Here again, electronic reconnaissance information, when combined with
supporting data, helps to complete an analysis..
G.. Level of Soviet Operational Readiness
The achievement and maintenance of a state of readiness involves
actual use of most types of electronic devices for training operations and
maneuvers. When reasonable familiarity has been gained with the devices
involved, and their place in Soviet organization is known, the state of
readiness may be estimated from the extent of such use. Last year, for
example, it was determined through electronic reconnaissance that the
state of readiness of the Soviet air defense of Eastern Germany had in-
creased considerably, because radar stations which had previously operated
for only eight hours per day went on twenty-tour-hour schedules.
H. Indications of Enemy Action and Intentions
The use of electronic reconnaissance data in indication schemes
requires an integrated listening network wherein the enemy history and
operating norms can be established and a continuous watch can be maintained.
Any abrapt-change in the over-all intelligence picture may signify an
enemy action or an enemy intention to take action. The sudden introduction
of a number of new devices, or the sudden withdrawal of devices previously
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identified would show a change in order of battle which might be important.
? sudden increase or decrease in activity should likewise be considered as
an indication of action or impending action. The poor coverage which now
exists with our own.air defense radar makes it probable that the enemy
use of bomber navigational radar may be the first indication we shall
receive of a surprise air attack. While it is not possible to place
complete confidence in electronic reconnaissance as a sole source of
intelligence for any of the categories listed above, it should be used
wherever available as it is one very important aspect of a well-rounded
intelligence prograu.
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II. DESCRIPTION OF THE ELECTRONIC RECONNAISSANCE PROCESS
As in other reconnaissance or observation processes, it is possible
to divide electronic reconnaissance into a number of steps which are
usually carried out in chronological order. Chance events will sometime
modify this order, but in general the process includes a preliminary
step of detection of the signals of interest, an intermediate step of
reception in which the signal characteristics are measured and recorded
to the necessary precision, and a final step of analysis in which the
signal characteristics are examined and compared with other intelligence
information. It is sometimes necessary to repeat parts of the process
many times in order to provide sufficient precise data.
A. Detection of New or Unusual Signals
Early detection of new or unusual signals is necessary in order
to prevent technical surprise. The detection operation is roughly similar
to pioneer reconnaissance in other fields. It recuires the coverage of
as much of the radio spectrum and as much territory as possible in order
to pick out a small part of the search region for more concentrated
attention. The major problems of detection differ to a considerable
extent with various frequency bands. The propagation mechanisms which
operate in these bands make the detection problems differ from band to
band. In bands where there is little long-distance propagation and a
low density of transmitters, the major problem of detection is that of
providing a radio receiver with high sensitivity and a very wide coverage.
In cc~r bands; where long-range propagation is good, and'where there may
be a high density of transmitters, the major problem of detection is that
of locating a new or unusual signal against a background of many similar
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signals. Early solution of the detection problem is very important be-
cause considerable time may be required between detection of a new signal
type and satisfactory analysis of the device or system in which it occurs.
In some cases it may be possible to omit the detection phase and
proceed immediately with the reception phase. These are usually cases
in which other intelligence evidence has demonstrated the existence and
approximate characteristics of anew type of enemy equipment before its
radiations have been detected. For examples photographs
of the Soviet
V -beam radar were obtained in Moscow, and a set had been seen in Gdynia
before the signals from the set were detected in electronic reconnaissance
operations. In the case of the Gdynia equipment, the previous observation
of the set made it possible to start electronic reconnaissance with a
specific reception operation based on estimated characteristics. In other
cases, electronic detection has occurred long before other intelligence
provided any information.
B. Reception of Data for Analysis
Equipments which are suitable for gathering the precision data
required for technical analysis are often useless in detection because
they examine such a small part of the field at any time that. they have
a very low probability of receiving any new or unusual signal. On the
other hand, the equipments which have large probabilities of detection
of new or unusual signals are often inadecuate to produce the precision
data required for analysis. The reception phase of electronic reconnaissance
is a process in which detailed search is directed to specific targets. The
data to be obtained fran the reception phase will be discussed under the
heading of signal analysis.
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C. Analysis of Received Data
The analysis phase of electronic reconnaissance consists of two
parts. In the first part, the data from the reception phase is analyzed
to yield the desired signal characteristics; in the second part the signal
characteristics are used in connection with all other forms of intelligence
information to produce finished intelligence of the types described in
section I.
1. Signal analysis
At any receiving antenna a radio signal can be described in
tense of 'a time-varying electromagnetic field with certain polarization
and direction of propagation. It is common practice, however, to generate
and transmit signals of interest without reference to this exact physical
description and to state the results of signal analysis in other terms,
which can be defined as follows:
a) Frequency
In present day detection and reception operations the
frequency of the signal is read from the dial of a receiver or a frequency
meter or estimated from the face of a cathode-ray indicator.. This tech-
nique is satisfactory in many cases, but it may leave something to be
desired in complicated situations.' The most common type of radio signal
is produced by generating a sinusoidal volt age and modulating this voltage
with a waveform determined by the purpose of the electronic device. With
this type of modulation, and with most others, it is possible to locate a
strong Fourier component 'ae signal at the originally generated fre-
quency. This frequency is usually called the carrier frequency. There
are, however, a number of modulation systems such as single sid eband,
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frequency modulation, and pulse modulation in which the carrier is some-
times suppressed completely or reduced to a level comparable to that of
the other Fourier components of the signal. Under these conditions it
is important to know the entire spectrum of the signal, as it is possible
to report erroneous frequencies when the receiver bandwidth is narrow
compared with the modulation bandwidth, and the modulation is not recognized.
Carrier frequencies of interest in electronic reconnaissance ran from a
few kc to 100 kmc or more.
b) Modulation type
The common methods of modulating a signal are to shift
its amplitude or its frequency in accordance with the modulating waveform.
In some cases, both amplitude and frequency are shifted simultaneously or
independently. Either or both types of modulation may be discovered by
displaying an oscillogram of the actual electromagnetic wave at the receiv-
ing antenna and examining it for amplitude and/or frequency modulation. It
is more common, however, to operate on the received signal with amplitude
or frequency-detector circuits and to examine the modulation waveforms
which are produced,
a) Modulation waveform
The fastest time variation of the electromagnetic field
at the receiving antenna is usually that associated with the carrier or
radio frequency of the signal. Superimposed on this variation is a slower
variation in either the frequency, phase, or amplitude of the radio signal
which, when denoe>w -'.ed, can be presented as a definite waveform. This
waveform may be classified for analysis purposes as cyclic, randomly
repeated, or random. In the case of a cyclic waveform, such as that
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emitted by an air navigation beacon, a description of the waveform over
one complete cycle is sufficient to describe it for all time. A randomly
repetitive waveform, such as the response of an IFF transponder, may be
described in terms of a complete waveform together. with a statement of
the times of occurrence of the repeated waveform. A random waveform,
such as that from a noise jammer, can be described only in terms of a
complete waveform record or of some statistical parameters. Communication
signals are usually much more random in nature than non-communication signals.
A simple radar system, for instance, has a waveform which is cyclic, whereas
a simple radiotelephone involves the random waveform of speech. Modulation
waveforms are recovered by demodulation of the signal and recording of the
resultant wave on a medium appropriate to the speed required. When the
waveform is so random that it is of little use in analysis, it may be
converted intoa power spectrum or an autocorrelation function for comparison
with other waves, or it may be cross correlated with other known or unknown
forms to discover relationships between them. Modulation frequencies from
a few cycles per second to several hundred Mc are of interest in electronic
reconnaissancee
d) Direction or location of transmitter
Direction data establish whether a signal originates from
friendly or enemy territory and provide a means of sorting in regions where
signals are numerous. Location. data can be used in identifying particular
pieces of electronic equipment and in many of the intelligence analyses
outlined in section I, particularl..- , n_ establishing order of battle. Al-
though it is usually sufficient to measure azimuth or map location, in
some cases elevation data may help in analysis. Accuracies required in
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 Approved For Release 2009/09/28: CIA-RDP89B00708R000500070002-6
R-22- s CONFIDENTIAL
9-1-53
22
directicn and location finding vary widely with the use made of the data.
For photographic work or attack, positions should be determined within
one half mile or less. Other applications may be more or less critical,
e) Sip.ial strength
In theory, a transmitter of. given effective radiated
power-at a known location-transmits a signal which can be received through
an antenna of known cross section and known. location. This signal can be
amplified by a receiver of known gain to a measurable level so that the
power level of the transmitter can be computed. In practice, the propaga-
tion between transmitter and receiver often varies.by a large and unpre-
dictable factor, and the cross section of the receiving antenna and gain
,of the receiver are unknown functions of frequency. Signal strength at
the receiver output alone is therefore a rather unreliable measure of
power at the trananitter output. Reasonably careful calibration will,
however, distinguish between transmitters of markedly different power,
when their positions are known, and between close and distant transmitters
when their power levels are known, When other data, such as the purpose
of the device and its range, are known, the necessary average power can
be computed, and the necessary peak output power can be computed from a
measurement of the antenna characteristics and the modulation duty cycle.
An estimate of power output also helps to establish the physical size
and weight of the enemy device,
f) Scanning pattern
The very ""did electrical vibrations at the antenna have
been described in terms of frequency, and the somewhat slower ones in
terms of modulation. A fluctuation which. is usually slower than the
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~' ` Approved For Release 2009/09/28: CIA-RDP89B00708R000500070002-6 ``"'""
 Approved For Release 2009/09/28: CIA-RDP89B00708R000500070002-6
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modulation is that associated with a scanning antenna system. Many of
the electronic devices considered in this report have high-gain antennas
which are turned mechanically in order to direct the antenna radiation.
When this is done on a reasonably regular basis, it is called scanning;
the time pattern of antenna motion, as revealed by the time pattern of
response of the receiver, is called the scanning pattern of the device.
In the case of air-surveillance radar, for instance, the antenna beam
is relatively narrow in azimuth and broad in elevation. The scanning-
pattern is usually one in which the antenna rotates. continuously around
a vertical axis so that the pattern of signal strength at the receiving
antenna is a time display of the horizontal antenna pattern of the
transmitter. In more complicated cases, such as the Palmer scan which
is used. in the search mode of air interception radar, the time pattern
of response of the receiver is a complicated function of the location
of the receiver in the radar search pattern and of the actual nature
of the scan pattern.
g) Polarization
The use of an electronic device determines the polariza-
tion which is normally selected. A particular linear polarization is
used to increase or suppress ground reflections, and circular polariza-
tion is used in some cases to discriminate against reflections from
rain. It is important to know the polarization of a victim device in
countermeasures. This may be measured by choosing the receiving antenna
polarization which gives the best signal, or by rotating the polarization
of a plane polarized receiving antenna,
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 Approved For Release 2009/09/28: CIA-RDP89B00708R000500070002-6
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CONFI DENTIAL
h) Operating schedule
As has been discussed, the time interval occupied by the
scan pattern is usually longer than that occupied by a modulation cycle,
but shorter than the daily operating schedule of a device. The operating
schedule which is to be measured here is a statement of the times of
starting and stopping operation of the device and the times of significant
change in modes of operation, such as starting and stopping scanning or
changes in power level. It is important that this daily schedule be
observed in the evaluation of such matters as readiness. The times of
starting, stopping, and other changes in the operation should be measured
as accurately as possible so that correlation with other intelligence
observations will be possible. A precision which will permit comparison
of measurements from different receivers to less than one second would
be very desirable in many cases. For example, in comparing intercept
data from two or more receivers concerning the flight of a short-range
guided missile it would be very valuable to know the time correlation
of the different radiations involved,
2. Intelligence analysis
This part of the analysis phase is the one in which signal
characteristics developed from intercept data are used in conjunction
with other intelligence to produce results such as those discussed in
section I. It should be emphasized at this point that no one form of
intelligence data can supply sufficient information rbout any of the
items listed in section I. A complete anal requir?s that data
collected from all sources be brought together rapidly and combined
freely to yield the desired intelligence. Since valuable military
information is carefully safeguarded by an enemy or a potential eneny,
CONFI DENTIAL
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9_~553
even the existence of our intelligence operations must be kept within
some security restrictions. On the other hand, security can become a
barrier in the development of useful intelligence by interfering with
proper combination of different forms of data and proper collection
efforts. An optimal security policy would be one which is flexible
enough that it could be readjusted continually; it should provide security
appropriate for each situation and still allow the use of the information
by the largest possible number of collectors and analysts. Some of our
efforts might become known under such a policy and as a result some sources
would be "dried up". However, technology and methodology of intelligence
collection and evaluation would change with sufficient rapidity to make
security breaks much less serious then they would be with a set of fixed
methods.. Also, some improvements in technique would undoubtedly result.
from being able to readily adapt our intelligence activities to the
current situation. The cost to the eon ' of continually improving security
measures to protect his secrets would increase considerably, and his
technical advancement would be hampered.
An an example, consider the policy on information derived from low-
level voice radio traffic. This type of information can be very important
in many research and development problems in the United States. Its wide-
spread use would no doubt result in the discovery by the Russians that it
was being used. Experience with this method of communication shows, how-
ever, that the application of strict security measures contributes to
confusion, lost motion, and poor results. Development of ?-4+able security
devices for these low-level circuits would be a very expensive and prolonged
program which would draw much effort from other useful projects.
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Intelligence analysis controlled at a single security classification
is probably not enough to produce the best results in this part of the
process. An analysis should be made with the data available through
open or less shielded sources, and at the same time a more complete
analysis should be made with data obtained through the most closely
guarded sources. The analysis at low classification should be dis-
tributed as widely as security will permit, and it should be modified
by the highly classified analysis where possible. For example, when
intelligence data are sent to operational commands for their immediate
use, every-effort should be made to keep information of different
security levels separate so that maximum use, can be made of the low-
level material, unhampered by the classification of the higher-level
analysis. Nhen an analysis of high security information contradicts
the low-level one, or when there is possibility of a dangerous error in
the low-level analysis, an attempt should be made to justify the necessary,
changes within the proper security limits.
Some intelligence items, such as aclear indication of impending
military attack, are so perishable that maximum speed must be used in
all phases of collection, analysis, and transmission of the information
to competent authority.
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III. GEDGRAPHY AND PROPAGATION
The extent of effort needed in electronic reconnaissance is deter-
mined partly by the locations of the Soviet transmitters which send out
signals of interest and partly by the propagation of the signals from
the transmitters to possible intercept stations. In this section a
sketch will be made of the probable distribution of Soviet and satellite
electronic devices of interest, and the extent to which we mad expect to
receive signals from these devices without flying-over any part of Soviet
dominated territory will be shown.
A. Map Distribution of Electronic Devices
Figare 1 is a map of the Soviet Union and satellite states, show-
ing the territory which Russia is now committed to defend and expand. The
shading of Fig. 1 is based very roughly on the estimated distribution of
electronic devices of potential reconnaissance interest. The cross-
hatched area indicates the region we are now able to cover without flying
over Soviet territory, and most of the frequency range of interest. This
map shows that very little information can be obtained Pram many important
areas. Although our coverage in Europe is fairly good, and we have a
significant potential in the Black Sea area and the Far East, enough space
remains in central Russia and Siberia to permit the development, productions
training, and maneuvers necessary to the complete readiness of a special
force of very large size, in an area which is completely protected from
external electronic reconnaissance.
B. Propagation of Radio Signals.
Although the map of Fig. 1 covers the majority of the frequencies
of interest in electronic reconnaissance, the propagation situation should
be examined in more detail. For this purpose the major modes of radio
CONFIDENTIAL
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 Approved For Release 2009/09/28: CIA-RDP89B00708R000500070002-6
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RM-1135 CONFIDENTIAL.
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propagation are outlined briefly, and some of the results to be expected
in particular cases are shown. Figure 2 illustrates how the propagation
mechanisms are related to radio frequency and the typical ranges of
operation which may be achieved through use of the different effects.
Ground-wave or surface-wave propagation may be described in terms ox
diffracted or guided radio waves around the surface of the Earth. 'o'ho
surface wave which travels in the air around the surface is accompanied
by a current wave which travels in the surface. Propagation depends on
the conductivity of the Earth, its dielectric constant, and the radio
frequency. At very low frequencies, propagation is excellent-along sea-
water paths.. This frequency range is thus used for world-wide communica-
tion and navigation. The penetration of the wave into the water enables
a submerged submarine to receive and send signals on these wavelengths.
As the radio frequency increases, the surface wave becomes much
less important, and the sky wave, in which the radio signal is reflected
from ionized layers in the outer atmosphere becomes dominant. Sky-wave
propagation is complicated and highly variable. No effort will be made
to treat it in detail here. It is principally important between about
3 Mc and 30 Mc, although these limits may change drastically with time
and position. Under good conditions, world-wide propagation is possible.
Under bad conditions, propagation by this means fades out completely.
At any time and at any place there is a definite upper frequency beyond
which the ionosphere will not reflect the signals back to the Earth's
surface. In spite of its variability, sky-wave propagation is used for
world-wide communication and navigation, and there have been suggestions
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 Approved For Release 2009/09/28: CIA-RDP89B00708R000500070002-6
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10 kmc
SHF
Atmospheric r
forward scatter.
\.a
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Ducting
(Tropospheric
refraction)
Ionospheric
forward scatter
MF
1 me
LF
100 kc
10 100
ky wave
10,000
Fig. 2 -- TYPICAL PROPAGATION RANGrS IN MILS. This figure shows
which propagation mechanisms dominate particular frequency
ranges, but it does not apply to any particular case, or
show the tremendous variations which occur with time and
specific, path.
CONFI D.ENTIAL -
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-CONFIDENTIAL
that it be used for long-range radar.
When there is a line-of-sight path, either in a straight line or
along a line of atmospheric refraction between the transmitting and
receiving antennas, propagation is good. The extent of this path
depends, of course, on the heights of the antennas above the surface
of the Earth and on the atmospheric conditions along the path. Where
the atmosphere is "normal", the effective rate of change of the index
of refraction with altitude is such as to make the Earth look about 4/3
as big as it actually is. 11is leads to a formula for line-of-sight
ranges, d - 2ht ? 2hr, where ht is the transmitter height, and hr
is the receiver height above the level at which the ray path comes
closest to the Earth's surface; d is in miles and h is in feet.
The atmosphere under some weather conditions shows abnormal varia-
tions of the index of refraction with altitude. When the index falls
more rapidly than normal, there is a chance that the refraction will be
sufficient to make the Earth appear flat. This trapping or ducting
usually takes place over ocean areas or over flat land areas and is
effective for signals above-some critical frequency. The critical
frequency depends on the height of the abnormal index curve and on
the severity of the disturbance. In sane places, such as the Black Sea,
anomalous propagation of this type is normal during the summer months.
Ducting is shown on Fig. 2 as it becomes important at frequencies above
40 or 50 Mc. In many places ducting extends radar ranges greatly be-
cause it provides very good propagation when it occurs.
When ducting does not occur, it is often possible to observe signals
at long ranges by atmospheric scattering. In experiments on propagation
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 Approved For Release 2009/09/28: CIA-RDP89B00708R000500070002-6
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conducted over the North Sea, it was found that at the radio horizon the
signal level began to fall rapidly as predicted by diffraction theory,
but after the level had fallen about 60 decibels below the free-space
level, the rate of fall diminished until it was nearly the free-space
rate again. This observation was explained by the scattering of
signals due to atmospheric turbulence and by the varying index of
.refraction of the atmosphere with height. Atmospheric scattering
becomes useful when there is a high-power transmitter with a high-gain
antenna, and when the receiver is sensitive and equipped with a high-
gain antenna. This phenomenon was used in the Baltic area to intercept
signals from a Soviet V-beam radar at a range of about 340 miles, with
both receiver and transmitter near sea level. Although the phenomenon
may persist at lower frequencies, it is much less important than other
modes of.propagation at freouencies below 30 Mc.
The ionosphere is also a varied and turbulent medium. The National
Bureau of Standards was able to demonstrate highly reliable propagation
over distances of 600 to 1200 miles at 50 No., using high-gain antennas,
high-power transmitters, and sensitive receivers. Communication circuits
based on this effect have now been put into operation.(1) Frequencies
between 30 and 100 Mc are of principal interest. Figure 3(2) shows the
(1) D. K. Bailey, Re lar VHF Ionospheric Propagation Observable over
Long Distances, National eau of Standards, Report No. 5-A- 11,
30 June Confidentiail.).
(2) R. C. Raymond and K. H. Underwood, Radio Wave Pro a ation, Haller,
Raymond and Brown., Inc., Report No. 3 - , 1 October 1952
(Confidential) 9
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 Approved For Release 2009/09/28: CIA-RDP89B00708R000500070002-6
RM-1135 lr Vfl l'' _ 11JMi 1V 1 L JLA
9-1-53
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g
7
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ro Ij / /
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 Approved For Release 2009/09/28: CIA-RDP89B00708R000500070002-6
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expected propagation levels which will be exceeded 50 percent of the time
as a function of frequency and distance for given transmitter power and
given gain of transmitting and receiving antennas. It is assumed that
the antennas are well below the radio horizon, that, propagation close
in is due to atmospheric scattering and that propagation far out is due
to ionospheric scuctering. Comparison of the lower curves with the
upper free-space curves shows the loss to be expected in the scatter-
type propagation. then ducting occurs, the propagation will fall above
the scatter curves and possibly as high as or higher than the free-space
curve. The scatter propagation is therefore not observed under ducting
conditions.
The general result of propagation considerations is that intercept
stations will need to be located within 200 or 300 miles-of points of
major interest in the Soviet Union and satellite countries to be sure of
securing intercept data. This conclusion is used in plotting Fig. 1.
Some specific radar interception ranges have been computed in a
separate report* (l) Examples of the ranges to be expected in particular
cases are given in Figs. 1 through 10.
(1) S. B. Soltwedel and A. L. Hiebert, Interception Ranges of Typical
.R~adars The RAND Corporation, Research Memorandum RM- ,
1 November 1953 (Secret).
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 Approved For Release 2009/09/28: CIA-RDP89B00708R000500070002-6
RN-1135 CONFIDENTIAL.
9-1-53
-36-
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CONFIDENTIAL
Approved For Release 2009/09/28: CIA-RDP89B00708R000500070002-6
 Approved For Release 2009/09/28: CIA-RDP89B00708R000500070002-6
CONFIDENTIAL-.
RM-1135
9-1-53
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CONFIDENTIAL
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 Approved For Release 2009/09/28: CIA-RDP89B00708R000500070002-6
P.i-1135 CONFIDENTIAL
9-1-53
-38-
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Approved For Release 2009/09/28: CIA-RDP89B00708R000500070002-6
 Approved For Release 2009/09/28: CIA-RDP89B00708R000500070002-6
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9-1-53
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CONFIDENTIAL.
=-~; -- Approved For Release 2009/09/28: CIA-RDP89B00708R000500070002-6
 Approved For Release 2009/09/28: CIA-RDP89B00708R000500070002-6
RM-3-135 CONFIDENTIAL
9-1-53
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CONFIDENTIAL
Approved For Release 2009/09/28: CIA-RDP89B00708R000500070002-6
 Approved For Release 2009/09/28: CIA-RDP89B00708R000500070002-6
CONFIDENTIAL. RM-1135
9-1-53
-41-
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CONFIDENTIAL
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 Approved For Release 2009/09/28: CIA-RDP89B00708R000500070002-6
HM-1135 CONFIDENTIAL
9-1-53
-42-
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CONFIDENTIAL
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 Approved For Release 2009/09/28: CIA-RDP89B00708R000500070002-6
CONFIDENTIAL
RM-1135
9-1-53
-b3-
IV. ELECTRONIC RECONNAISSANCE SYSTEMS WITHOUT OVERFLIGHT
It has been established that an electronic reconnaissance system
must perform the functions of detection, reception, and analysis of-the
electronic reconnaissance data. Considerations of geography and propaga-
tion have shown that the receivers used in the detection and reception
phases of this process must be distributed rather widely in space in
order to achieve significant coverage of possible Soviet sources. At
the same time comprehensive, properly correlated intelligence is needed.
The electronic reconnaissance system must therefore involve a considerable
number of intercept stations at which the detection and reception opera-
tions may be carried out, and a smaller number of analysis centers properly
organized to receive data rapidly from the intercept stations, produce
results desired at the local level, pass out requests for additional data,
and pass on for higher analysis both the raw data and the results of the
primary analysis. The entire system must be mobilized under an adequate
chain of command and provided with adequate communication facilities to
permit rapid exploitation of new developments.
A. Intercept Stations
Experience has shown that it is generally desirable to house a
number. of individual equipments and operators in a single vehicle or a
single location so that they may be provided with common security,
communication, and logistic support. The optimum number of equipments
and operators in each case will depend on the density of signals to be
investigated, the time available, and the range of signal characterist4 !
to be accommodated. This small collection of personnel and equipment will
CONFIDENTIAL
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 Approved For Release 2009/09/28: CIA-RDP89B00708R000500070002-6
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b e called an intercept station, Several general types of intercept sta-
tions have been developed in the course of electronic reconnaissance
work to date, and we may expect the development of new types as the
necessary equipments become available.
1. Types and locations (vehicles)
Intercept stations may be sited at selected-ground points or
may be transported and used in suitable vehicles. Each type of installa-
tion has its own unique advantages and disadvantages. A complete elec-
tronic reconnaissance program requires several types of stations. In a
later phase of this study the number of stations of each type necessary
to provide good electronic reconnaissance will be determined, and sugges-
tions will be made for locations and organization of these stations into
effective networks,
a) Ground fixed
A permanently established ground station with adequate
space is an ideal location for the operation of complicated and sensitive
equipment and for the use of very-high-gain antennas. It also has the
advantage of being able to remain in operation continuously for long
periods of time. There is no effective limitation on the space, weight,
and power available for the operation of special purpose intercept equip-,
ment, and there is no limitation on the number of operators who may be
used if necessary. The position of a ground station is not subject to
navigational error, and the station furnishes a much more stable platform
for use of high-precision receiving and recording equipment th_'r n air-
craft or other vehicle.
.CONFIDENTIAL.
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 Approved For Release 2009/09/28: CIA-RDP89B00708R000500070002-6
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RM-1135
9-1-53
On the debit side, a ground station must be installed close to
en. borders to be useful, because of the propagation problem outlined
.above. Its operations are subject to enemy observation, its personnel
and equipment are subject to capture, and its fixed location makes it
liable to a number of countermeasures. Such a station cannot maneuver
to take advantage of favorable propagation conditions in other places,
and it cannot secure a high-altitude look into enemy territory. It
cannot make a number of direction finder readings on a transmitter of
interest; only the direction can be determined. It is therefore evident
that other types of intercept stations are needed.
b) Ground mobile
Ground station equipment which is housed in a truck or
trailer has some advantages over that in fixed locations. The equipment
may be moved more easily from one location to another, and it is possible
to build engineered installations in places with adequate facilities and
then move them quickly to the operating areas. On the other hand, space,
weight, power requirements, and operator comfort must be sacrificed some-
what for portability. The permissible size of antenna structures is
limited, and the equipment in the stations must be thoroughly rugged to
survive the shocks of transportation. Communication facilities are less
useful or less secure, or both. Mobile stations will probably be the
most satisfactory ground stations in the event of ground warfare. In
pre-D-day use, they will probably function mainly as satellites for the
more permanent stations, or they will operate in the same place for so
long that they will gradually acquire the large antenna structures,
additional shelters, good communications, and other facilities of fixed
stations.
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c) Aircraft
Specially equipped aircraft have been used in electronic
reconnaissance operations for some time. They have the advantage of
extreme mobility. They can penetrate land and sea areas which are not
suitable for the erection of other stations. They can reach high altitudes
so as to take advantage of the beat propagation conditions.
Specially equipped aircraft are very expensive. The conditions of
audible and electrical noise and vibration to which their equipments and
operators are subjected are very annoying. No use can be made of high
gain antenna systems; and the weight, size, and power supply limitations
on equipment are severe. The aircraft cannot guard particular locations
for long periods of time, and the number of hours of actual operating
time per month is not impressive.
Aircraft stations should therefore be directed carefully. toward
specific objectives in detecting and receiving signals, through the use
of all available information. Wherever possible, fixed or mobile ground
stations should be used. Aircraft should be used only where other stations
cannot operate because of the terrain or where the existence of the air-,
craft may elicit a desired type of enemy activity which would not other-
wise be obtainable. For example, reconnaissance of the Baltic coastline
or the northern border of Russian territory is probably most practical by
air. Aircraft might also be used to put the enemy air defense system on
the alert-in order to study its radiations.
In addition to the specially equipped aircraft, it may be found
desirable to use aircraft which fly regularly scheduled routes that might
yield useful information. Such routine flights will require a new approach
to the equipment problem, which will be brought out later in the section on
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equipment. There are many cases. where a suitable piece of equipment on
one of these aircraft could obtain information which could not be obtained
by the specially equipped aircraft*
d) Missile
A missile or a pilotless aircraft would be useful in non-
overflight operations. only if it offered some advantage in the way of high
altitude or penetration of an area which could not be obtained with either
the routine-flight or the specially equipped aircraft. The missile station
would require generally the same type of equipment as the aircraft station,
with the important difference that human operation would have to be eliminated
and no advantage could be taken of human judgment. Ballistic missiles which
might be fired to extremely high altitudes would command very long lines of
sight into Soviet territory without overflight, but the time which a single
receiver station would spend at the high altitude would be so short that
the value of such an operation for electronic reconnaissance purposes is
questionable. The firing would certainly have to be directed at some
specific objective and timed on the basis of intelligence data to attain
the desired result. Aerodynamic missiles would have little advantage over
conventional aircraft in border operations except that the risk of loss or
capture of personnel would be reduced, and the experience gained in the
border operations would be very valuable in the event of overflight, using
the same or similar. missiles.
e) Free balloon
A completely new approach to equipment development will be
required for best use of free balloons in electronic reconnaissance. The
weight and power supply limitations are considerably more drastic than
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those encountered in aircraft or missile operations. On the other hand,
the vibration and noise problems are much reduced, and the balloon plat-
form is very stable. Balloon flights can reach altitudes up to 100,000
feet. The trajectory of a free balloon cannot be accurately predicted.
In flights which are not intended to go over Soviet territory it would
be necessary to monitor the balloon position continually and to bring
down the essential parts if the balloon crossed an established limit.
As in the case of missiles, free balloons have little to offer in non-
overflight operations which cannot be achieved by aircraft. On the other
hand, the experience gained in using balloons in non-overflight operations
would be invaluable in case overflight operations become possible. Under
some conditions a balloon could be launched in Western Barope, and would
have a useful life of several hours or perhaps a day on or near the border
of Soviet dominated territory. Such a flight could yield significant
data. However, it should be repeated that an entirely new research and
development program is required to implement a balloon for electronic
reconnaissance,
f) Large ship
The exclusive availability of a large ship, either a
naval or a merchant vessel, for electronic reconnaissance is unlikely.
Large ships are even more expensive than special airplanes. An intercept
station established in a large ship would be able to carry out electronic
reconnaissance only on targets of opportunity within the normal range of
its travel. A large ship can furnish sufficient space for equipment and
for antennas of reasonable gain. Power supply is adequate. Working
stations are fairly comfortable, and noise level is reasonable. Repair
and maintenance facilities are usually good. Although a large ship is
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less mobile than an aircraft and the regions in which it can penetrate
are much more limited, it can remain on station much longer than an air-
craft, and it is suited to a slightly different class of duties. The
presence of the ship may call into action enemy electronic devices,
particularly those of naval interest, which would not be brought into
use by the presence of an airplane. Ccmmunication facilities are usually
good. The map of Fig. 1 shows that the Pacific area offers a considerable
opportunity for the use of ship stations, as do same small regions in the
West*
g) Small ship or boat
A small ship or boat will provide less space for equipment
and personnel and will be limited.to smaller antennas than a large ship.
Such a boat, however, can penetrate waters in which a ship would not be
risked for reconnaissance purposes, and it can remain on station for fairly
long periods of time. The boat might also be disguised as a fishing vessel
in order to minimize its threat, or it can be operated in such a way as to
exaggerate its threat in order to bring about desired enemy responses. A
tender or shore based logistic support would be required at frequent inter-
vals. There are many uses for a boat in this type of service, and the ex-
pense of the smaller types is comparable with.that of the special aircraft.
As in the case of the aircraft, missile, and balloon stations, the boat
should normally be sent out with enough intelligence information to permit
the accomplishment of a detailed objective,
h) ent
When a trained man can carry some equipment into Soviet
controlled areas, make measurements, and report his results, he can make
a very worthwhile contribution to the electronic reconnaissance effort.
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The nature of the equipment he can carry is very limited in size, weight,
power supply, and complexity of operation. He can rarely use a high gain
antenna, and he can record very little information. On the other hand
he can often occupy a position which is very near the equipment in which
he is interested, and experience has shown that a skilled operator can
produce very useful information even with very limited equipment. Un-
fortunately, intelligence available at present from personnel operating
within Soviet borders is meager in quantity, and does not justify much
dependence. We must develop our external facilities to the point of
diminishing returns rather than wait for more from this source.
2. Equipments
Each of the station types mentioned puts its own limitations
on the design of equipments. In addition to these limitations different
equipment types are often needed for detection and'for reception, and all
of the conditions vary with the frequency range in which the equipment
must operate. During later phases of this study these conditions will
be examined in some detail and an attempt will be made to specify the
requirements for detection, reception, and analysis equipments which
will meet the conditions as well as possible. At present only general-
izations can be made*
a) Receivers for detection and reception
In detection, no attempt is made to learn all of the
characteristics of a new signal with the precision required for complete
analysis. The. characteristics are measured only well enough to tell
whether a signal is radiated by a previously known enemy device or
whether the signal is new or unusual in some respect. Receivers designed
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for detection operations may therefore be built with parameters such as
bandwidth selected on the basis of the operation rather than on the basis
of the expected signals.(1) For example, a pulsed radiation in the LF
region may be detected through use of a narrow-band communication receiver
which cannot respond to the pulse waveform of the modulation. At the same
time, the narrow-band receiver may be a better detection receiver than a
wide-band receiver would be in this case, because it may be necessary to
select the desired signal from a number of overlapping signals. The
narrow-band receiver would yield enough information about the transmission
to permit its identification as new and interesting, although it would not
transmit enough information to permit a study of the modulation waveform.
Any parameter such as bandwidth in'a receiver design is selected as a
result of compromise among a number of factors such as manufacturing toler-
ances, operating ease, noise level, interference, bandwidth of desired
signal, and technical ease of construction. In the design of detection
receivers for frequencies below about 50 Mc, the most important items
which must be compromised in selecting receiver bandwidth are the proba-
bility , of reception of-a short signal, and the rejection of interference.
If an intermittent signal of short duration which is well above the
receiver noise level is considered, and the detection receiver is tuned
randomly through a band of frequencies wider than the modulation band of
the signal, the probability of hearing the transmission increases as the
(1) A. L. Hiebert, RAND Electronic Reconnaissance Conference Summ
Report, The RAND Corporation, S-15, 1 August 1953 (Secret),
Chapter XIV.
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bandwidth of the receiver is increased. However, if the spectrum is
cluttered with other signals which are of no reconnaissance interest,
increasing receiver bandwidth also means an increased chance that the
signal of interest will be lost among interfering signals which are
received at the same time. Above about 50 Mc, the density of interfer-
ing signals is usually low enough to make the receiver noise the limit-
ing interference factor rather than undesired radio signals.
A great many of the receiver designs in use today were devised from
a background of communication receiver design. In communications, the
usual requirement is for the receiver to handle a single signal as well
as possible. In detection, it is often necessary to handle a number of
signals with unpredicted characteristics at unpredicted times and fre-
quencies. We may expect therefore a considerably different approach.
A detection system is responsive in a number of dimensions. In
addition to frequency, which has been mentioned, the aystem is responsive
in time, space, direction, polarization, and sometimes in modulation
characteristics. All of these aspects may be used to identify and
describe the detected signal and they must all be considered in the
design of suitable detection equipment. Propagation values are also
important in receiver design. For the intercept function it is nec-
essary to establish a number of stations to cover the area of interest.
If signals are normally propagated, say, 500 miles, the spacing between
stations can be of that order of distance, while with propagation distance
of 100 miles or less,. stations should be spaced much more closely. Yet it
would be wasteful to spread facilities for intercept of the long-range
signals in all of the closely spaced stations. Fortunately, signal density
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considerations and bandwidth requirements are also dependent on propaga-
tion so that it will probably be most economical to specify individual
equipments for each general propagation region. This leads to a selection
of four general spectral regions (section III). In the LF and VLF region,
extending to about 200 kc, there is long range propagation and relatively
high signal density. In the MF region the propagation ranges in daylight
are quite short, but signal density may be.high during the day, due to
crowded conditions of the band, and it is sure to be high at night. In
the HF region, there is usually good long range propagation, and signal
density is normally fairly high, especially at night. In the VHF and
higher ranges, propagation over long ranges is not common, and signal
densities are not high except in a few special cases such as the concen-
traticn.of Soviet radar in East Germany or the concentration of radar in
the vicinity of a naval task force. These considerations suggest the
development of detection receivers for the ranges:
10 ke to 200 kc
200 kc to 5 Mc
2 Mc to 50 Mc
30 Mc to 100 kmc
One unit should not necessarily contain all of any one of the bands, but
the receivers which fill that band should have roughly similar character-
istics, because the conditions under which they must detect signals are
similar. It would be desirable in this program to develop all of these
equipments so that they could be used in any of the station types out-
lined above. T his is hardly practical, however, because some stations
are manned and others are not; and the mechanical and electrical require-
ments on a receiver for use in a missile, for instance, would certainly
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prevent use of the same equipment in a free balloon. We must, therefore,
in later parts of our continuing study examine each of the situations in
detail to determine the minimum useful number of types and the order of
priority in their development.
A preliminary estimate of this situation appears in Table I. Here
the station types have been grouped so that limitations of size, weight,
complexity, and power supply are approximately the same in each row of
the table. Each square in the table may therefore represent a single
equipment design or a single set of equipment designs to cover the
indicated frequency range within certain weight, size, power supply,
and mechanical limitations. The relative importance of each set of
.equipment designs has been estimated roughly. This may be modified
somewhat.in later reports on this study.
Table I
RECEIVERS REQUIRED FOR DETECTION AND RECEPTION OPERATIONS
Detection
Reception
Station Type
10-200
200kc-
2-50
30Mc-
10-200
?OOkc-
2-50
~OMc-
kc
5Mc
Mc
100kmc
kc
5Mc
Mc
100kmc
Ground fixed
Large ship
High
High
High
Low
High
High
High
Low
Ground mobile
Small ship
Low
Low
Med.
High
Low
Low
Low
High
Special aircraft
Routine aircraft
Guided missile
Low
Low
Low
High
High
Balloon
Med.
Low
High
Med.
Low
High
Agent
Low
Med.
Low
Med.
Low
Med.
Low
Med.
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Theoretically, a good detection receiver would have a learning capacity.
It would show response to a particular type of radio signal until the
analyst or operator decided that the signal was of no further interest.
The receiver would. thereafter ignore or eliminate the particular type
of signal or would alter its response to it in a beneficial way. This
type of equipment is probably some distance in the future, but it repre-
sents an objective which should be considered. Marc of the techniques
now used in computer memory circuits may be applicable to this problem.
A receiver designed primarily for the reception process more nearly
resembles a communication receiver than does one designed for detection.
In reception, the receiver characteristics must be keyed to those of the
signal to be received. Bandwidth, for instance, must be selected with a
view to passing all essential components of the signal, instead of merely
detecting the existence of the signal. At the same time, the existence
of the detection operation makes it unnecessary to maximize the proba-
bility of intercepting the signal, because a detection receiver of high
probability can usually be used to locate the signal in the spectrum.
This is similar to the use of pioneer reconnaissance to select small
areas for more intensive observation.
More consideration will be given in later reports to the selection
of receiver characteristics, but a few rules of thumb may be stated at
this time. In the ranges below 50 Mc atmospheric or cosmic noise rather
than internal noise in the receiver usually limits the reception of
small signals. Receiver bandwidth in this region should be matched as
closely as possible to signal bandwidth. The majority of radio systems
using single transmitters and antennas in this frequency range are
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Limited to bandwidths of about 10 percent of the carrier or center fre-
quency. This limitation comes from the necessity of matching low-impedance
antennas to tubes of higher impedance. The reactive circuit elements in.
the matching networks limit the bandwidth over which this can be accomplished.
There are a number of current development programs in the field of communica-
tion and navigation which will produce signals that are dispersed across
considerably wider bands. However, these will generally be multiple systems,
and it will be necessary to receive their signals in multiple channel re-
ceivers, each of which may be fairly narrow in bandwidth.
A general rule in both detection and reception is that the equipments
should provide the maximum possible number of simultaneous open receiving
channels, to increase the probability of detection and reception of signals
transmitted by complicated multichannel systems*
b) Antennas and D/F
Antenna systems for use with detection or reception equip-
ment must perform the following !unctions:
(1) Deliver the maximum signal strength to the receiving system
from the area in which the transmitters of interest may be
located.
(2) Help to eliminate interfering signals and noises.
(3) Work with the receiver and indicator in direction and/or
position finding.
Each intercept station places its own requirements and its own limita-
tions on the antenna system which may be used. In an aircraft station, for
instance, the gain of an antenna is limited by the space which it can occupy
and by the uncertainty in the direction from which a signal may be received.
In a ground station much more space is available for the erection of
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high gain antennas and there is usually a better idea of the direction
from which signals are desired. For the elimination of interference it
is as useful to have a controllable null in the antenna pattern as to
have a sharp maximum. As a detailed part of our continuing study the
antenna requirements of each type of station will be examined and a lay-
out of suitable antenna systems will be made. Gains will be chosen to
meet operational requirements and to permit realization of the antennas
within the confines of space usually available.
Direction finding antennas form a special case which has been handled
separately in most past development programs. This study will evaluate
the feasibility of including direction finding with the normal complement
of station antennas. If this does not prove feasible, requirements will
be determined for. the direction finder antennas needed for the various
station types*
c) Recorders
In both the detection and reception phases of electronic
reconnaissance, important data can and should be preserved through the
use of recorders. Studies have shown that the operator of a detection
or reception system has a limited capacity for absorption and retention
of information, that he may make gross errors in writing data on logs,
and, that it is possible to supplement his ability very considerably by
use of recording devices. However, experience in a number of fields has
shown that it is entirely possible to record so much information in such-
a complicated manner that analysis is very difficult. It is necessary to
examine each type of operation in each of the station types to determine
what information should be recorded, the time available for its transmission
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and ana ysis, and the necessary storage period of the recorded information.
When these factors have been established, it will be possible to devise
the best recording and read-out systems for use in the detection, recep-
tion, and analysis operations. In any system in which a large quantity
of.data is preserved'for later analysis, it is vital that the recording
.j,-stem and the read-out system be designed to function cooperatively.
Generally speaking, recorders with responses varying froma few
cycles per hour or less up to many Mc per second will be needed. Record
lengths will vary from seconds to days or months, and the total recorded
information will vary over wide limits. In many cases the cyclic or
repetitive nature of waveforms used in electronic devices will permit
considerable economies in the recording process. A repeated radar pulse,
for example, may be compressed in bandwidth from megacycles to kilocycles
and recorded on audio equipment. In the case of a random function of any
bandwidth,. it may often be sufficient to record the power spectrum or the
correlation function on a narrow-band device. In a general purpose recep-
tion system it will be most helpful to record the waveform information
according to the general categories of frequency, modulation, scan pattern,
and operating schedule outlined in Section II.
Part of the continuing study will be devoted to determining require-
ments for recording and playback devices for all of the operations described
above, for both attended and unattended equipments,
d) Indicators
An indicator is a device which presents information from a
receiver to a human operator. Many of the devices now referred to as
analyzers are indicators within the meaning of the term used here. An
indicator should be desipsied to present to the operator that information
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on which he is required to take action in a readily assimilable form.
The presentation of unnecessary data or the presentation of data which
require excess mental effort on the part of the operator can do great
damage to the operation. Human engineering studies in the Aero-Medical
Laboratory.at WADCW and elsewhere have shown the value of proper indi-
cator design in many fields. Careful attention should be given to this
aspect of indicators in electronic reconnaissance.
Generally speaking, all information which the. operator needs for
control of the equipment in accordance with his instructions should be
'presented to him, but any excess information which might be confusing
should be recorded without presentation. The expected level of skill
and training of intercept personnel is an important consideration here.
An attempt should be made, of_course, to secure the best personnel avail-
able for the electronic reconnaissance program, but there is a great deal
of competition for good personnel, and many operations will be done by
airmen with poor backgrounds in fundamentals and very little practical
experience. With the development of a complete program, it will probably
be desirable to retain the most capable people in the analysis centers
and to rely on less experienced personnel to operate relatively intelligent
equipment in the intercept stations. This means that a great deal of
consideration must be given to proper indicator design and proper installa-
tion of equipment in the stations. Visual indicators must be brought to
eye level and made large enough to permit easy reading without fatigue.
(1) A. L. Hiebert, RAND Electronic Reconnaissance Conference Summary
Report, The RAND Corporation, S-15.9 1 August 1953 (Secret )#
Chapter VII.
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Indicators which should be viewed simultaneously should be brought within
the sane visual field. Light intensities should be arranged so that no
great changes are experienced in looking from one indicator to another
(as, for instance, fray a cathode ray tube to a tuning dial). Wherever
it is necessary to read and write, the indication which is read should
as new :y resemble what is to be written as possible. Controls should be
located within easy reach and grouped in normal sequence. The individual
control knobs and levers should be shaped so that they can be distinguished
by touch, and they should convey some sort of impression of the operation
which they carry out whenever possible.
The indicator requirements for each of the operations in each of the
station types will be considered and an attempt will be made to devise a
consistent approach to the indicator problem throughout the electronic
reconnaissance field. The results will, of course, depend on the antenna
and receiver designs and on the way in which the load is shared between
indication and recording.
B. Analysis Facilities, Locations
The results of a good electronic reconnaissance program are useful
at a variety of levels. It will be necessary to distribute analysis fa-
cilities organizationally and geographically to meet these needs. At the
sane time, the facilities cannot be spread too widely, as there is sane
benefit in centralized facilities which can be better staffed and better
equipped than those which-are widely separated. Each electronic re-
connaissance otation must. have' enough analysis ability to determine whether
or not the received signals are of interest and whether or not particular
missions assigned by canmand have been completed.
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The next higher degree of analysis should be at a level which cam, ands
the electronic reconnaissance effort for a particular geographical area,
such as a theater of operations. This level is chosen because it can be
served with adequate, rapid communication, and because a mobilization of
all of the intercept stations in such an area under a single analysis
center and a single operational control will produce electronic reconnaissance
data with the highest efficiency for & 'given total expenditure. This suggests
an analysis center in England with possible forward elements in Germany and
Africa, and an analysis center in Japan. Additional centers might eventually
be needed in the Middle East, Alaska, and possibly the Philippine Islands.
Analysis at the station level should be confined to signal analysis
sufficient for the purposes outlined above. At the theater analysis centers,
all intelligence information pertinent to the theater should be available
for combination with refined signal analysis to permit complete intelligence
evaluation of the electronic reconnaissance data for information of the type
outlined in Section I. This should include communication intelligence as
well as attache information, reports of agents, defector interrogations,
and general background accumulated from open literature. In this connection
it may be found more expedient to incorporate electronic reconnaissance
information into the regular theater-level intelligence effort than to
create all of the new supporting tasks for proper use of electronic re-
connaissance data in a separate analysis center. A decision on this point
must be based on the relative quantities and values of the different types
of intelligence information and on the degree of security which is deemed
essential in safeguarding any particular source of information. It would,
of course, be preferable to assign these new functions to a properly
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augmented existing organization, provided this did not result in loss of
valuable information through lack of attention or through excessive se-
curity. This organizational problem will be dealt with in more detail in
further study of the electronic reconnaissance program.
A final level of analysis must, of course, be maintained in the United
States. At this level, reports from all of the theaters are combined and
correlated, and any additional information which may develop from other
sources is fed into the system. Summary reports prepared here should
serve in the guidance of technical planning and force programming at
the highest levels. At the same time these reports would serve as a
basis for planning: additional electronic reconnaissance operations. The
reports should also be sent down to the theater analysis centers and,
where possible, to the field to serve as inspiration and information
for personnel at the lower levels.
1. Signal analysis to yield measurable characteristics
At the analysis centers, the amount of information which will
be accumulated in a relatively short time will make it necessary to use
machine methods of data storage and recovery. A number of methods of
storing electronic reconnaissance data have been suggested, and some of
them have been worked out in detail.(') Those which make use of punched
business machine cards are probably the most promising at present. In
(1) Beacon Hill Report, Problems of Air Force Intelligence and Reconnaissance,
Project Lincoln, Massachusetts Institute of Technology, 1 June 1952,
(Secret), and A. L. Hiebert. AND Electronic Reconnaissance Conference
S Report, The RAND c:oiporatioi_, S-15. 1 August 953 (Secret)s,
Chapter II*
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most of the cases so far investigated the business machine card can carry
enough information to identify a particular intercept experience or a
particular enemy electronic device with complete satisfaction. Where more
detailed or unusual information is needed, the punched card can serve as
an index card to permit the quick location of the actual data on filed
records of other types. The adoption of a uniform U.S. card punching
scheme would be of some value as it would permit ready. interchange of
data and would focus the attention of all analysis centers on the same
aspects of the problem. On the other hand, there is little reason for
the wide circulation of the vast quantities of data in a punched card
file, and standardization might cast the process in a mold which would
be too rigid to permit future growth. In any case, it is safe to conclude
that signal analysis equipments will be required in the electronic re-
connaissance system to take data from the logs and records of the inter-
cept stations and produce punched cards with a minimum of human effort.
Particularly in the case of the unattended receivers, which must be
carried in missiles and balloons and in routine aircraft flights, it
will be desirable to develop analysis machinery which will receive the
records from these equipments, encode the desired information, and punch
it on the cards.
When the information from intercept operations has been applied to
punched cards, it will be possible to perform a great many statistical
and comparative operations with automatic machines. A11 of the individual
interceptions of a particular transmitter may b. sorted out and correlated,
and a single card may be prepared for each transmitter. When this has
been done, the distribution of transmitters in frequency and in geography
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may be worked out by machine, and summarized information will be available
for comparison with other data in the intelligence analysis step.
One of the results to be s au ght in later work will be the general
specification of analysis center equipment and personnel requirements to
go with the station and station equipment requirements to be determined
as outlined above.
2. Intelligence analysis, using all forms of collateral data
The interpretation of the characteristics of received signals
in, terms of desired intelligence objectives, such as order of battle, is
a process which has never been successfully formalized and reduced to the
rules of deductive logic. Electronic radiation is one observable aspect
of enemy activity. It happens that it. is one of the most readily observable
aspects at reasonable distances. Electronic data can contribute significantly
when combined with other aspects such as enemy communication, known enemy
systems of transportation, logistic policy, and personnel and training
philosophy.
It is important that the role of electronic devices in enemy operations
be understood. To do this most efficiently a background of data must be
accumulated, a number of possible enemy system frameworks must be projected,
and our observations must be fitted in as they are made, in order to
.develop the intelligence picture. Characteristics to be expected of a
Soviet air interception radar set, for example, can be derived from the
requirements which. are placed on.that set for use in the observed Soviet
aircraft and for operations with the observed Soviet GCI radar sets against
our known aircraft. Coupled with these system facts is the observed Soviet
propensity for producing and using equipments similar to those we find use-
ful. This framework of facts and suppositions has led to a search for
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air-interception radar signals similar to those radiated by the SCR-720,
and the rejection of some slight evidence of use of a much lower frequency
set.
It is evident, therefore, that- the final intelligence analysis phase
of electronic reconnaissance is not one which belongs to electronic re-
connaissance alone. Observations from all sources, including communica-
tions, photo, attachis, agents, literature, and others, must be brought
together on a basis of common availability and subjected to a complete
comprehension. There has been no computer built to date that is better
than the human brain for this process. It is unimportant from the national
interest standpoint whether this aver-all function is performed as an
adjunct to the electronic reconnaissance program or the photo reconnaissance
program or the communication intelligence program, so long as it is done
thoroughly, and so long as the security safeguards which must be established
around the results are made as reasonable as possible.
C. Command of Electronic Reconnaissance Effort
The United States Department of Defense now has the largest stake
in an effective electronic reconnaissance program, although there are other
Federal agencies which are also interested in its results. Within the
Department of Defense the program must support the individual intelligence
needs of the armed services as well as.the general oven-all intelligence
requirement in the determination of national policy. Considerations of
uniform availability of information and prevention of duplication in elec-
tronic reconnaissance would seem'to call for a single command of the e].,,c-
trcnic reconnaissance program under an agency of the Government or the
Department of Defense, but the individual intelligence requirements of
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the individual armed services and the benefits to be derived from a certain
amount of free competition tend to argue for separate command of the pro-
grams by the authorities of the three services. This question cannot be
settled at this time; but it will be kept in mind in further study of the
requirements of the electronic reconnaissance program. Theater command
of electronic reconnaissance is a somewhat simpler oe,o^3tion.
1. Unified command at the theater level
There electronic reconnaissance teams may be brought into
contact with Soviet forces, there is little doubt that all of the facilities
available in a particular geographic area should be brought under a unified
command. As has been mentioned, each type of station has unique capabilities
depending on its location and its equipment. Coordinated operation of
stations of all types will often be required for the most effective deploy-
ment of electronic reconnaissance forces for a particular problem. It is
therefore apparent in this activity, as in other military operations in
the face of an enemy, that it is desirable to bring the operations under
control of a single commander who may be free to use the forces as he sees
fit, and who is personally responsible for the execution of instructions
given him by higher echelons. The electronic reconnaissance commander
should work closely with the theater analysis center. He should support
the theater commander by-furnishing appropriate electronic reconnaissance
information, and he should be responsible for meeting requirements placed
by headquarters in the United States for electronic reconnaissance within
his capabilities. It was shown several times in World War II that cooperative
operations among air, sea, and ground stations could bring out information
which could not be gathered otherwise. This effort may often be organized
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on a basis of general agreement at theater level, but it should be insured
by the proper establishment of a theater command organization with opera-
tional control over the stations.
2.- Use of all intelligence in programming effort
Within a theater or a smaller operational sector, it will be
possible to gather electronic intelligence much more rapidly if the elec-
tronic reconnaissance effort is programmed on the basis of current intelli-
gence information. All sources, including communication intelligence,
should be used by the theater electronic reconnaissance commander to
formulate operating schedules for all of the electronic reconnaissance
stations in his theater. This programming should include watch and
operating schedules for the ground stations, position and operating
schedules for the mobile stations, flight schedules and operating sched-
ules for the aircraft stations, routing and operating schedules for
ships and boats which may be available, instructions for use of receivers
in routine aircraft flights, and instructions for any missile or balloon
operations which may be undertaken. In addition, instructions should be
formulated for the activities of agents when they are available.
When electronic reconnaissance operations are conducted on a basis of
uninstructed search, the probability of detecting and receiving significant
signals is considerably reduced. The use of all forms of intelligence in-
formation in directing search in certain geographic regions at certain
times and in certain frequency bands for certain types of signals can
very greatly increase the chance of gaining a complete picture. In addi-
tion, this type of scheduling permits cooperative scheduling of other
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intelligence operations which can result in much improved finished intelli-
gence. When there is danger of compromising a high security source of in-
formation, cover plans must be worked oat to permit the operation to continue
under disguise.
3. Dissemination of electronic intelligence
After gathering a complete intelligence picture of enemy
activities and intentions, it is highly important to make this informa-
tion available to people who need it. Sometimes this need conflicts with
the need to conceal our sources-of information and the need to keep the
enemy guessing as to how much is known about his situation. In some cases
inadequate security destroys the revealed sources of information and permits
the enemy to plan more logically. On the other hand, an overzealous security
policy may play into enemy hands by preventing our full use of intelligence
information.. Lack of knowledge and failure to act on it are operationally
equivalent.
Classification as low as permitted by security
The need for wide di ssenination of electronic intelligence
coupled with the need for-security suggests a number of different levels of
analysis and dissenination of the results of electruiic reconnaissance.
Preliminary analysis and results applicable to field problems should be
available as rapidly as possible at the individual sectors. More sophis-
ticated analysis should go on simultaneously in the theaters,. and final
analysis at several security levels should be carried out for appropriate
distribution in the United States. -Care should be taken at eve'^- :,4ep to
produce material at the lowest practical level of classification, and
highly secure information should not be mixed with lower classification
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data except for the preparation of high level reports. Material of great
value to commercial research and development companies, for instance, can
often be prepared at a ,Confidential or Secret level and used to good
advantage, whereas a Tpp Secret document could not be so widely distributed.
11. Coordination of electronic reconnaissance with other collection
efforts
Electronic reconnaissance continually draws target information
from other types of intelligence activity and at the same time can furnish
target material to such activities as photographic reconnaissance. As an
example, when new radar frequencies were detected by electronic reconnaissance
operations in 1944, the station location on the basis of direction finder
plots was turned over to the photo reconnaissance wing with a request for
low-level oblique coverage. The resulting photographs returned to elec-
tronic analysts enabled a much better description of the new radar type
and a better analysis of its performance. To make the most of this type
of cooperative operation it is necessary for'the personnel of other re-
connaissance efforts to be aware of the benefits of successful electronic
reconnaissance. This can best be demonstrated by furnishing them useful
data. The missions of other collectors, such as attaches and agents, may
be augmented in the same way.
D. Communications in Electronic Reconnaissance
Widespread, successful electronic reconnaissance operations cannot
be carried out without rapid, explicit communications in both directions
along the chain of command, and in other directions as well. These
communications are, of course, subject to enemy communication intelligence
efforts, and provisions must therefore be made for security as well as
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speed. Further, it is often a matter of considerable interest to transmit
waveform information or other data which cannot easily be spelled out in
spoken or written text.
1. Communication needs
Communication requirements in the electronic reconnaissance
process can be expressed in terms of the lines of communication needed,
the estimated flow of traffic over these lines, and the acceptable delay
in transmission of messages and data over the lines. In common with all
other intelligence collection devices, an electronic reconnaissance station
is a point at which an early indication of enemy attack may be received and
recognized. A message announcing this information is very important and
should not be delayed, even for reasons of security. It is therefore
important that each electronic reconnaissance station have a communication
facility which is immediately accessible for a small quantity of high
precedence traffic. Security on this system is desirable, but is con-
siderably less important than the quick transmission of the message.
The line of communication over which this message travels can well be
the direct line from the station to the sector or theater analysis center,
provided that there is a qualified 21-hour-duty officer at the center to
receive this message and notify the proper authorities.
.A second rapid line of communication is needed between two or more
stations which are cooperating in a single operation. Here, rapid commu-
nication is essential for such activities as the coordination of direction-
finder activity or concentration of facilities on a newly revealed target,
but in this case the need for security is probably as great as the need
for rapid communication. The volume of traffic is fairly small, but any
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appreciable delay is intolerable. This problem will be examined more
fully in later reports in uh ich an attempt will be made to compare the
cost of operation without adequate communication facilities against the
cost of establishing sufficiently complicated facilities for this purpose.
The lines of communication by which operation schedules are trans-
mitted from control points to stations and by which received data are
transmitted back to analysis centers can tolerate some delay in the
interest of security, but they also pose peculiar problems in some
respects because of the requirement for transmitting data in pictorial
form. Maps, waveform pictures, circuit diagrams, and other pictorial
data should not normally be delayed long enough to go by regular courier
service, although a special courier service might be adequate and might
be less expensive than the necessary secure electrical communication.
Lines of communication from overseas theaters to the United States
are required to pass brief, summary information rapidly and to follow
through with detailed information on a slightly delayed basis. Trans-
mission times for secure communications of the order of one hour.or two
will not be objectionable, provided that high precedence messages con-
cerning an imminent outbreak of war or a similar emergency can be passed
more rapidly. Some types of detailed information should be sent by
electrical means, and others can be sent by courier without any large
penalty provided that local action which might be based on them has
already been ordered ',; the theater or sector control center.
2. Possible solutions
For the communication link between stations involved in a
coordinated operation, there is no substitute for a wire or radio circuit
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with on-line cryptographic facilities. This type of equipment can be
provided for use in some stations, but it is expensive to operate, and
the situation will require further study before a suitable recommendation
can be made. For communication with aircraft and ship stations involved
in combined operations, short-teen security could be obtained through the
use of pro forma procedures, brevity codes, broadcast techniques, and
other special signals; but none of these is adequate to produce long
term security, and most such procedures attract enemy attention and
increase enemy interest in recovering the significance of the traffic.
Further.study will be necessary to specify the term of the security
which is required in these operations and. to suggest specific solutions.
Communication links between intercept stations and control stations
in which a small delay is tolerable can be served by current cryptographic
techniques, and in many cases the necessary messages can be sent over
existing communication services. existing facsimile circuits, because
of their lack of security equipment, are not satisfactory for the trans-
mission of pictures, drawings, and diagrams. At present, magnetic tapes,
photographic films, and other record material must be delivered to the
analysis center by courier service.
Present electrical communication facilities between the United States
and overseas theaters are probably adequate for the additional traffic
from electronic reconnaissance, and present message handling times of
the order of two to six hours are not objectionable for most of the in-
formation to be processed:in this system. Present courier times of the
order of one week seem excessive for much of the information of interest.
Means of speeding up this type of communication should be studied,
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V, OVERFLIGHT SYSTEMS
Most of the considerations in connection with'an electronic recon-
naissance system without overflight can be applied to overflight systems.
Overflight would not effectively modify much of the activity which has been
discussed. It would merely extend the reach of the airborne stations, and
it would carry electronic reconnaissance into areas which cannot be observed
at all without overflight. The overflight facilities could be fitted into
the rest of the system as it is envisioned here.. Operations orders and
schedules would be based on intelligence data, and cooperation between
overflying and non-overflying stations would be arranged. Intelligence
missions would be arranged with other collection agencies to observe the
total reaction to overflight missions. Overflight by means of manned air-
craft, guided missiles, and free balloons will be discussed. Each method
has its own peculiar advantages for specific purposes.
A. Manned Aircraft
Under present and foreseeable conditions, a U.S. aircraft over
Soviet territory would be subject to attack by the Soviet air defense
forces. Protection against such an attack would normally be sought by
making the flights under cover of darkness or bad weather and by flying
either at an altitude high enough to avoid anti-aircraft fire and make
fighter performance poor or low enough to avoid continuous radar surveillance
and tracking.
1. High-altitude mission
A high-altitude mission would proceed on the assumption that
the aircraft was being continually tracked and plotted by the Soviet air
defense forces and that Soviet reaction might vary from amused curiosity
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to attack by fighters or guided missiles. With available aircraft types,
this mission could penetrate from U.S. bases overseas to any point in
Russia and return. Coverage could be obtained on all of the interior
region which is now effectively concealed. Success in finding unusual
types of signals would depend on the use of properly designed detection
and reception equipments, on'the Soviet reaction, and on the means for
data recovery in case the aircraft is shot down or forced down through
mechanical failure. Arrangements made in advance for transmission of
important data by radio from the aircraft would be subject to the security
and communication problems that have been mentioned. The most satisfactory
method of data recovery would be to have the aircraft return to base and
land with the information. The extent of information which would be
obtained might be limited by the choice of darkness and bad weather as
a time for operations. Signals connected with research and development
activities and those connected with training would be less likely during
that time. The depth and effectiveness of the air defense network would
probably be revealed by the efficiency in tracking the intruding aircraft.
The advantage of this information should be balanced against the risks of
loss of the aircraft and crew and the risk of provoking international
friction. Resolving power required in the detection and reception equip-
ment for the individual analysis of interfering signals would be quite
high in the high-altitude mission. In East Germany, for instance, an
aircraft at 60,000 feet would be visible to several hundred radar sets
on. both sides of the frontier at the same time.. With deeper penetration,
this density would probably diminish.
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The big advantage of 'overfli ght with manned aircraft over other
techniques is that aircraft for some phases of this operation are
available now. Others could be equipped quickly with available types
of receivers. These would not be the best stations which could be
devised for this type of activity, but they would give us far more in-
formation than we are now getting out of the central parts of Asia.
More study will be required to determine the exact scale of high-altitude
effort which would pay, but an initial assignment of five to ten aircraft
to this service would yield much useful reconnaissance data.
2. Low-altitude mission
The low-altitude mission would be much harder for the Soviet
air, defense forces to track and plot, so that it might gain access to
some regions which could not be pentrated at high altitude, and it might
reach some areas before adequate warning of its arrival could be broad-
cast. On the other hand, the reception range of the low-altitude air-
craft is quite limited, and navigation is also difficult. Receiving
equipment for the low-altitude mission would not need the high resolving
power of that used at high altitudes because the signal density would
never be so great. Aircraft and equipment suitable for this type of
mission are now available. Data recovery by commnunication poses the
same problem as in the case of the high-altitude aircraft, but there
is probably a better chance of recovering the aircraft. If the enemy
is unable to plot the aircraft accurately, there is some chance that
unusual defense force behavior will be observed which will be useful
from an intelligence standpoint. Low-altitude flights in which the
navigation is good can pinpoint the locations of intercepted devices
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fairly well, because they do not hear them over long ranges. The low-
altitude aircraft suffers in the same way as the high-altitude one in
flying at night-and in bad weather. Many of the activities of interest
are probably off the air. At the same time, much useful information
could be collected in this way. The risk would be about the same as
h st for the high-altitude operation.
B. Guided Missiles
Pilotless aircraft or aerodynamic missiles such as the Snark,
Matador, or Navaho, offer a,somewhat better chance of overflight without
the risk of personnel, but with perhaps an increased risk of a serious
incident. Vehicles of this type now available do not in general have
sufficient range to fly into Russia to the required distances and return
to U.S. bases. On two-way missions they could cover a part of the terri-
tory of interest, and on one-way missions they could cover it all. On
the two-way missions, it would be possible to recover the missiles or
parts thereof for recovery of the data. on one-way missions, the use of
high-frequency radio telemetering of the intercept data to ground stations
would not be objectionable from a security standpoint, since the launching
of the missile on a one-way mirssion would require a previous decision of
the same security question. A suitable data transmission system could be
developed fran available components. The missile is somewhat behind manned
aircraft in time of availability because of the lack of suitable unattended
receiving systems. Complete requirements for these systems are awaiting
the resrlts of this and other similar studies.
The risk involved in a missile flight of either the one-way or the
two-way type is considerable, but conditions under which this risk would
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be justified maw be imagined, and it is quite likely that when they occur,
there will not be time left for the development of suitable equipment. It
Mears, therefore, that, subject to further study, development of ' unatterrled
equipment for these activities and actual experimental flights in missiles
can be justified.
A guided missile offers a facility which cannot be duplicated with manned
aircraft for intentional excitation of defense systems so that their reactions
may be observed and analyzed.(1) If a reconnaissance missile is actually
fired on by electronically controlled devices, the use of suitable receiving
and transmission equipment will permit analysis of the devices which would
be hard to obtain in any other way.
Since the guided missile would most. probably operate at high altitude,
the resolving power required in its receiving equipment to separate signals
for recording and transmission to base will be comparable to that required
of the equipments. in the manned aircraft. This is an exceedingly difficult
and complex problem, and further studies are needed before definite recom-
mendations can be given. When a missile excites the defense system, there
is little chance that it will accumulate research and development informa-
tion from interior, laboratories or other types of radiation which are
carefully safeguarded. It is possible that later developments such as the
Navaho, and the satellite missile will escape detection or will not excite
the defense forces. These missiles may be used to collect information
which would not be available to a missile which would excite the defenses.
(1) A. L. Hiebert, RAND Electronic Reconnaissance Conference Summary
Report, The Rkff Corporation, 5-15., 1 August 1953 Secret ,
Chapter XIII.
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C. Free Balloons
The type of vehicle which probably offers the smallest risk in
overflight operations is the free balloon, (1) Such vehicles have been
built to carry substantial weights. Launching and recovery techniques
have been worked out, No suitable electronic reconnaissance equipment
has yet been designed, and it would probably require a minimum of three
years to produce operationally useful models. Weather data show that
during acme months of the year, launchings from a single area in the
North Sea would result in coverage of all of the important regions of
the Soviet Union and most of the satellite nations, with a maximum
probability in the central part.(2) By making the gondolas as small
and light as possible, it would be practical to expect flight at very
high altitudes. Detection and plotting of the balloons would be unlikely,
and attacks on then would probably be impractical. No particular balloon
could'be programmed to cover any given area at any time, but a number of
balloons launched at intervals of a few hours would probably 'guarantee
coverage of the point in question at least once. The line-of-sight
propagation range of nearly 400 miles attainable from 70,000 feet would
mean a very high density of signals at the balloon during a large part of
the flight. High resolving power would be required for work with individual
signals. Good statistical data on distributions of signals in frequency
(1) W. W. Kellogg, S. M. Greenfield, D. T. Griggs, Preliminary Study, Pioneer
Reconnaissance by Balloons, The RAND Corporation, Research Memorandum
NovembA+ `,5_0 -(Top Secret).
(2) W. W. Kellogg, S. M. Greenfield, Revised Study of Pioneer Reconnaissance
Balloons, The RAND Corporation, Research Merorandum HM-979, 30
November 1952 (Top Secret).
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might be obtained with equipment of lower resolving power. The balloon
is probably the only vehicle which will be available in the next few
years which might fly over sensitive interior areas during working hours
without exciting the defense system. For this reason it might be the
only vehicle which would obtain much information on Soviet research and
development and on the training of new forces deep inside Soviet territory.
Data recovery from the balloon could be by recovery of the essential
parts of the gondola in the Pacific area. Some techniques for this have
been established. The organization and the equipment required are not
out of proportion with the results expected. An.alternate system, in
which the balloon would transmit results over long range by radio would
require the use of high-frequency radio signals. (1) This system is less
secure and is also subject to jamming. The Soviet Union has the best
developed jamming organization in the HF region that has ever been ex-
hibited. It might be possible to communicate small amounts of information
without *interference, but for the relatively large amount desired, -recovery
of the gondola is a more promising approach.
As in the case of missiles, the risk of overflight' operations with
balloons should be re-evaluated continually. (2 ) The fact that such opera-
tions may not seem advisable should not be cause for. deferring the equip-
ment development, because the political situation can change much more
rapidly than the development program.
(1) L. E. Larmore, ElLectronic Considerations for Missile Reconnaissance
The RAND Corporation, Research Memorandum R1 -1 , 2 April 19 3
(Secret).
(2)
This is the subject of a current RAND study which has not yet been
reported,
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VI. ORGANI ZATI ON FOR ELECTRCNI C RECONNAISSANCE
It has been determined that the personnel who gather, transmit, and
analyze electronic reconnaissance data must be distributed in a number of
areas throughout the World, and their work must be integrated closely
with the work of personnel who gather, transmit, and analyze all other
forms of intelligence. data in order to provide the most complete and
well-rounded intelligence picture possible. An organization for electronic
reconnaissance must provide for:
(1)
Operational control of small, widely scattered groups of personnel
who operate electronic reconnaissance stations throughout the
World.
(2). Rapid transmission and analysis of received data at several
different geographic, operational, and security classification
levels.
(3) Close cooperation, or integration with other intelligence collection
and analysis systems at all applicable levels, both for operational
control and for analysis.
(1) Supplying and administration of properly trained personnel for
collection and analysis activities.
(5) Logistic support of collection and analysis facilities. This
includes both conventional housekeeping support and a highly
specialized technical support. The technical support must
provide a great degree of flexibility in the numbers and types
of,equipments supp]'_:-' to the stations, and it must demonstrate
a quick reaction to any new enemy development which calls for new
types of intercept devices or new operating techniques.
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Such a wealth of intercept data can be observed at any electronic
reconnaissance station that it is necessary to plan operations directed
at the specific items of major interest. Particularly where two or more
stations in the same sector or same theater can be brought to bear on the
same intercept problem, it is important to firing those stations under
common operational control so that their attention can be directed ape-
cifically at the desired objectives. This need suggests that although
it may be desirable to keep the electronic reconnaissance organizations
of the three armed services separate at the United States headquarters
level, it is certainly desirable to bring the facilities of all of the
services under common operational control at the theater or sector level.
The retention of separate organizations in the United States provides
elements of competition and flexibility which are desirable, but competition
should be replaced by a high degree of cooperation during actual operations
,against an enemy* The need for common operational control suggests that
such control be exercised by electronic reconnaissance specialists on the
staffs of theater intelligence officers. All services maintaining forces
in the theater could be represented there. This type of organization would
provide for integration of the electronic reconnaissance effort with other
intelligence efforts and for satisfaction of the requirements of the theater
commanders as well as the requirements of their headquarters in the United
States. It would also provide effective theater support for the electronic
reconnaissance forces, which is always desirable.
Electronic reconnaissance information and the intel'ic.;ance developed
from it are needed at a number of command levels. and at different levels
of security. classification. In general, the most detailed information is
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needed at the lowest command levels. As this information. flows upward from
the intercept stations through the analysis centers, it can be summarized.
and combined with other' intelligence data to produce intelligence of
progressively greater. general interest, and (usually) progressively higher
security classification. The organization by which electronic reconnaissance
data are transmitted upward through analysis ~ucilities should be laid out
accordingly. Since electronic reconnaissance information is a perishable
commodity, the organization must be designed for very rapid data transmission
and analysis to provide the necessary information at each level on a current
basis with the required speed and within the limits of a reasonable expendi-
ture for communications.
As an example, let us consider intercept data with respect to a new
type of Soviet radar system. It will be assumed that the data are collected
during the course of a day as a result of directed search in a ground station
near the border. The original intercept information at the station may be
quite detailed. It will contain the time of each interception of the signal,
photographs or sketches of the waveform, scanning pattern, and signal strength
variations observed, frequency readings, estimates of pulse repetition rate,
d/f bearings, and any other data which can be observed. As the program
continues, the same sort of data may be produced each day over a period
of several weeks.
The original interception of the new type of signal might be the occasion
for a high-precedence message to the theater control center, giving the time
of intercept, frequency, and other distinguishing ch racteristics of the
signal so that appropriate action might be taken in alerting other stations
for the same signal or same type of signal. Later, accumulation of more
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data might call for a more detailed message summarizing the results of
the first few hours of operation. This message could be sent at an
,operational precedence, as it would be of value in directing further
operations at the control center. At the and of the first day the log
and all other recordings, films, and other data would be sent by courier
to the control center. Thereafter, information concerning the -operation
of the particular system could be transmitted to the control center in
periodic summary messages at a precedence determined by the control center
and the daily logs and records could be forwarded by courier. This is
current practice in some installations.
Information concerning this development would be of immediate value
to the local ground, air, and sea commanders. They would need the general
characteristics of the radiation of the set, its estimated purpose and
place in enemy order of battle, its specific location, probable physical
appearance, and vulnerability to countermeasures so that they could be
prepared for operations which might involve this particular piece of
equipment. Part of this information could be supplied on the basis of
electronic reconnaissance data alone. This could be released to field
units at a relatively low security classification. Part of it would re-
quire the corroboration and expanded detail which could come only from
combination with other intelligence data and would have to be classified
and released accordingly.
In the United States, the information given above would be of immediate
value to the headquarters of the operational commands. They should receive
the material at low security classification as rapidly as possible. Where
the highly classified information would serve to modifyr the results appreciably,
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they should receive it also. The information useful in research, development,
and planning would not involve the complete detail required by the operational
commands. The need for speed in transmission of the bare essentials to re-
search and development planners would be just as great, because research and
development decisions with a vast influence on the future are being made
every day, and any new piece of intelligence like the one mentioned may
modify such decisions considerably. Research, development, and planning
personnel would need to know the frequency band occupied by this type of
set, the average and extreme values of characteristics such as waveform,
output power, scanning pattern, physical size and weight, the approximate
number of sets of this type in use by the enemy, and the function of the
set in enemy systems. Exact order-of-battle information and exact locations
of the sets would not be needed for most purposes. Within the research and
development structure, the summarized information should be prepared at a
number of classification levels, for use by contractors, project officers,
and personnel responsible for plans and budgets.
Thus a flexible organization is required, to operate at several levels
with facilities for a relatively small volume of rapid communication and an
outlook for possible uses of intelligence information as well as for collec-
tion and analysis.
It has been a recurrent theme 'in this memorandum that electronic re-
connaissance supplies one type of intelligence data which must be combined
suitably with other types for the best results. This means that electronic
reconnaissance operations must be directed on the basis or in support of
other intelligence collection operations and that analysis of electronic
reconnaissance data must be carried out by personnel who have complete
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access to other forms of intelligence on a current basis.
These requirements suggest that electronic reconnaissance collection
and analysis be incorporated as specific functions in existing intelligence
organizations. Integration at the theater level is essential, because the
time lags involved in coordination at the higher levels are so great that
much of the benefit is lost. For example, there is little value in learning
that an opportunity existed to collect an item of intelligence interest
after the opportunity has passed.
This means, of course, that in some cases electronic reconnaissance
missions will be directed in support of requirements established by other
intelligence interests. This loss of sovereignity, however, should be
tolerated in view of the improved results obtained by the whole program.
Where originality in equipments, methods, and lines of attack on
particular problems are involved, there is some advantage in competitive
work among a number of organizations. This advantage can best be realized,
of course, with free interchange of information. This consideration weighs
quite heavily against the creation of a single, United States authority to
control electronic reconnaissance at the highest level. It is apparently
incumbent on those who wish to maintain the present, separate control to
show by their performance that they can indeed obtain the advantages which
are inherent in the system, without allowing any of the possible disadvantages,
such as overzealous competition, to damage the over-all effort.
There. are a number of personnel problems in connection with electronic
rne-onn ais sari r a. Some of then are listed below: -
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(1) Most of the operating locations and theater analysis centers are
outside of the United States, so that service in the electronic
reconnaissance organization is almost a guarantee of overseas
assignment.
(2) Phlisted military personnel,. who must do most of the operating,
are in service for such a short length of time that they have
only a limited opportunity to became experienced.
(3) Current military policy of continual reassignment of officer
personnel interferes with the development of real competence,
except in a few rare cases.
(14) As in other branches of intelligence, the rewards for good
performance in this field are largely confined to classified
feelings of personal satisfaction with a job well done. This
is insufficient motivation for a great many people.
Policies which may correct some of these difficulties have been advocated
in a number of places, but there are many obstacles to 'be overcome in the
proposed solutions.(1) Some gains may be realized by equipment development
programs, and improved training plans and mission assignments. For instance,
enlisted personnel, after a much abbreviated training in electronics, could
be sent directly to actual intercept stations for on-the-job training. They
do not need to know the principles of electron optics in order to operate
an intercept receiver. They need only to know what knob to turn to carry
out an assigned mission and what results to report. Improved equipment
design can aid in this respect.
(1) Beacon Hill Report, Problems of Air Force Intelligence and Reconnaissance,
Project Lincoln, Massachusetts Institute of Technology, 15 Jame 1952,
(Secret).
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The internal complexity permissible in a piece of equipment is de-
termined by the ability of maintenance personnel; in somewhat the same
way the permissible external complexity is determined by the ability of
the operators. If a small number of maintenance- personnel.can be very
well trained, they can service internally complex, conservatively designed
equipment for a relatively large number of poorly trained operators. Further-
more, in air operations, the operators are expended at a considerably higher
rate than the maintenance personnel, so the equipment should be made as
simple externally as possible,-and maintenance capability should be extended
to cover the resulting internal complexity. A balance in this sort of
thinking is suggested in a recent article on military electronic equipment*
(l)
One of the major features of electronic reconnaissance is that the
equipment development field is growing rapidly. Unpredictable, and some-
times radical, changes in direction may be expected. Many of these. find
us improperly equipped or organized to respond promptly. For example,
the recent Soviet development of Loran-type signals on 150 kc found the
United States without an adequate search receiver in this band. We would
be similarly embarrassed by the appearance of multichannel guidance and
control signals, radar in bands above 11,000 Mc, and a number of other
highly probable enemy developments.
Organizationally, such a situation requires a flexibility which is
seldom contemplated in the planning of military units. The force required
for electronic reconnaissance is small by military standards, and the
(1) R. J. Nordlund, Is Com lexit of Military Electronics Necessary?,
Proc. I.R.R., Vo , pp 9 - 7, August 1953.
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equipments which are used are usually purchased in small quantities, com-
pared with other types of military equipment. Yet electronic reconnaissance
is often burdened with the same type of overhead structure on supply and
procurement which is arranged for the large scale operations of such fields
as military communication. Time for establishing requirements is very
long. Procurement is slow. Reaction to a new enemy development is re-
stricted to illegal modifications of station equipment, improper assembly
of new equipment by personnel with inadequate facilities, and very limited
procurement of commercial equipment types which may or may not be suitable.
Perhaps. more than other intelligence operations, electronic reconnaissance
needs a built-in reaction capability, supplemented by a streamlined purchasing
procedure for the procurement of small quantities of badly needed hardware
at a speed commensurate with the need. This requirement can probably best
be met by the creation of a field laboratory and model shop organization
at theater level, operating under the theater control center and supported
by a purchasing technique which is realistically designed to carry out a
small amount of business on a rapid basis. Many of the equipments used in
electronic reconnaissance are required in such small numbers that they need
not be accepted and approved as military standard, provided that the organiza-
tion is designed to maintain them and able to purchase the necessary spare
,parts with minimum delay.
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VII. PROBLEMS FOR FURTHER INVESTIGATION
The following problems are contemplated as part of the continuing study
of electronic reconnaissance:
A. Determine the number of stations of each type required for
adequate electronic reconnaissance of the Soviet Union and the satellite
nations under pre-war conditions. Show how these stations should be
integrated into nets and coordinated with analysis centers. Show how
overflight facilities may be incorporated and used (1) in non-overflight
operations, (2) in overflight operations. Determine-the number of receiving
channels required in each station in each frequency band to assure a
reasonably complete coverage of the available information.
B. Study the operating conditions of detection and reception
equipments in all frequency ranges to specify the requirements which these
equipments must. meet.
1. Investigate frequency range, channel widths, number of
channels, scan rates, recording characteristics, and other features of
detection receivers for use in all types of stations. Among the problems
which will be considered here will be the detection of signals which occur
for very short times, and those which are shifted rapidly in frequency or
other operating parameters, such as pulse-to-pulse frequency dispersal
radar equipment. Long-range detection of electromagnetic radiations from
fission and fusion blasts will also be considered. Results of the signal
density study now under way in support of the active-war electronic re-
connaissance study will be used here to help in defining the detection
requirements.
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2. Determine frequency ranges, channel widths, number of
channels, tuning characteristics, correlation facilities, and other features
which may be required of receivers for reception use in all types of stations.
Co Determine the requirements of each type of intercept station for
antennas and lay out a minimum number of antenna types which might meet
these requirements. Examine the feasibility of including d/f capability in
the design of regular antenna and receiving equipment used in detection
and reception. If this is not feasible, work out requirements for direction
finders needed for detection and reception operations in all types of
stations.
D. Determine the requirements in detection and reception processes
for recording equipment and lay out general specifications which this equip-
ment must meet. Determine which equipments are most important from a stand-
point of the over-all program.
S. Determine the requirements-for indicators to be used in elec-
tronic reconnaissance work in manned types of stations. Show how the
indicator requirements are related to receiver design choices, recorder
choices, and requirements of human engineering.
F. Determine the organization required. for proper exploitation of
the opportunities offered by electronic reconnaissance. Show whether the
organizational needs can be met by modification and enlargement of existing
intelligence groups, or whether a new special force is justified. Show in
detail how existing organization or the special force could be integrated
with existing cold war organizations. By tie-in of this study with an
active war stuc -, show how the preferred organization would serve in the
prosecution of an active war. Determine whether complete unification is
desirable or not.
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Study the function of the analysis centers proposed in the
which can
yield this degree of security while permitting the operations to
first problem to determine what equipment and internal organizations they
require and to propose methods for their operation.
H.. Determine the communication requirements of the proposed
electronic reconnaissance networks and estimate the costs of operation
of the necessary circuits as compared with the additional costs of re-
connaissance carried on without electrical cownunication for part' or all
of . the, activities. Show what facilities would be required for transmission
of the items of special interest in electronic reconnaissance such as wave-
forms. Determine the period of security required in ground-to-air communica-
tion for electronic reconnaissance purposes, and suggest security measures
-continue.
I. Determine the-force of aircraft, missiles, and balloons re-
quired for overflight operations in.connection with properly organized
non-overflight activity.. Show what initial planning of routes and initial
listening schedules should be, and how the overflight organization would
tie in with the existing non-overflight organization. 'Determine the best
types oftvehicles for each overflight application and the requirements for
detection, reception, and recording equipment and for data recovery equipment.
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