INFORMAL MONTHLY PROGRESS REPORT NO. 3 FOR THE PERIOD 14 AUGUST 1955 TO 21OCTOBER 1955 SYSTEM NO. 2

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP81B00878R000200130016-4
• Release Decision: RIPPUB
• Original Classification: S
• Document Page Count: 23
• Document Creation Date: November 16, 2016
• Document Release Date: August 16, 1999
• Sequence Number: 16
• Content Type: PERRPT

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'Odor
nth1y rOgrese Report NO. 3
for the period
14 August 1955 to Al October
System No. 2
C.ntract No. A-101
CMCC Docwuent No. 163.2015
Copy 2 of 7 copies
This document contains information affecting the
National Defense of the United stmts within the
rneening of the Zspionage Law*, Title leo U. S. C.
Sections 793 end 794, It. tranemission or lb*
revelatioa of its contents in any manner to an
unauthorised person is prohibited by bile?
. CLASS. TO: T!.3 C 241:
!:`,17:XT REVEW DATE:
AUTH: HR "0'0-2
DATE: iftif
Rr:2..VE--_,IVER: 0
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TABLE OF CONTENTS
Paragraph Page
1-0. General 1
2-0, Fundamental Principles of The Navigation
Equipment
3-0. Antenna Arrangement of The Ground-Based
P-Wizfroii of the Nav fgaTficrriEitTaWnent
Grotuid-Based Navigation Equipment 7
4-i. :.equence of Operations 7
4-3. Major Components and Functionsof The Base-
Station Navigation Equipment 8
4-4. Navigation Timing and Control Unit 8
4-s. Navigation Range-Data Unit 9
5-0. lirborne Navigation Equipment
5-1. Sequence of Operations
11
6-0. Communication Equipment 14
6-1. General 14
6-6. Communications Pulse Sequence 15
6-11 ? Base- Station Equipment 15
6-18, Airborne Equipment 17
7-0. Form-Factor Considerations 19
APPENDED FIGURES
Figure Page
Figure 1. Geometry of Antenna System 20
Figure 2. Geometric hiterpretation of Equation 21
Figure 3. One-Hop Mode 22
a
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Figure 4.
Figure 5.
Figure 6.
Figure 7.
8.
9.
Figure 9A.
Figure 10,
Figure U.
Figure 12.
Figure
Figure
APPENDED FIGURES
(Continued)
Figure Page
Error Due To Neglecting The Height
of The Aircraft 23
Base Station, and Aircraft Navigation
Equipment Pulse Sequence 24
Base Station Navigation Equipment,
Block Diagram 25
Navigation Timing and Control Unit
(Ground Based), Block Diagram 26
Navigation Range-Data Unit, Block Diagram 27
Basic Airborne Navigation Equipment,
Block Diagram 2 8
Navigation Data and Timing Unit, Block
Diagram 29
Time Relationships, Communications System 30
Communications System Base-Station
Equipment 31
Communications System Airborne Unit 32
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1-0. GENERAL.
1-1, During the period covered by this report, two major
decisions regarding project orientation were made. The
first was the decision to consider the communication func-
tions of System No. 2 separately from the navigation func-
tions. The second was the decision to discard the concept
of a navigation system which depended on the radiations of
existing low-frequency broadcast transmitters to generate
position information.
1-2. The decision to consider the communication functions
separately from the navigation functions was made in order
to permit system design for each of these functions to pro-
ceed independently of the other and thus to achieve optimum
performance in each function. This decision was necessi-
tated primarily by the extra burden imposed on both functions
by the increase in operating range to 4000 miles. It is be-
lieved that greater reliability and efficiency in the final pro-
duct will result by designing system functions to meet specific
communication or navigation requirements rather than by
attempting the design of circuits which could be shared by
both functions. System components will be shared by the two
functions only when this does not compromise the requirements
of either. Transmitters and receivers, both airborne and
ground-based, for example, will be common to both the com-
munication and navigation portions of System No. 2.
1-3. The decision to discard the concept of a navigation sys-
tem dependent on the radiations of existing low-frequency
broadcast transmitters was founded on a combination of fac-
tors. The principle objections to this dependance were the
lack of rigid broadcast Operating schedules, the possibility
that countermeasures would be applied by unfriendly trans-
mitters, and the lack of sufficient suitable broadcast installa-
tions in the Middle and Far East to provide reliable coverage
of all areas. Further, an analysis of the propagation char-
acteristics to be expected revealed that fluctuations of field
intensity, due to various sky-wave modes, would make positive
identification of the active mode extremely difficult since un-
certainty in the downcoming wave angle would introduce an un-
certainty in the effective wave length as observed by the air-
craft in horizontal flight. This would require the introduction
of an average effective wave length in the computations for
these areas of uncertainty and would seriously compromise the
accuracy of position measurements.
1 4. Since the fundamental principles of the navigation equip-
ment described in this report have not yet been tested and
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proved, a concerted effort is being made to construct and
assemble an experimental equipment intended to test the
practicability of the system described.
1-5. In the case of the communication equipment described
in this report, however, the fundamental principles involved
have previously been tested and proved. For this reason,
there is well-grounded confidence in the practicability of the
communication equipment described and design of a proto-
type model has been started. Circuits are being bread-
boarded and tested only in those cases where performance
requirements are special or unique.
2-0. UNDANIENTAL PRINCIPLES OF THE NAYI
QUIPAMN?T.
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3-0. ANTENNA ARRANGE ENT OF THE GROUND-. BASED
PORTIONTWIREITAVICATIOW EQUIPMENT:
3-1. The ground-based portion of the navigation equipment
includes three grounded vertical radiators located at the
vertices of an equilateral triangle. (A separate rhombic an-
tenna will be used for reception at the base station.) First,
a pulse will be transmitted from antenna 1, then a pulse will
be transmitted from antennas 1 and 2 in combination, and
finally a pulse will be transmitted from antennas 1 and 3 in
combination. The ratio of the signal strength at the aircraft
due to simultaneous pulse transmissions from antennas 1 and
2 to the signal strength at the aircraft due to pulse trans-
missions from antenna 1 is a function of the azimuth angle and
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elevation angle from the base station to the aircraft. (See
figure 1.) This ratio is independent of mode of propagation
or range as indicated by the following expression:
Cos
where X1* Sig
where 4 vertical angle (see figure 1)
y = azimuth angle measured with respect to the reference
line
Cos ? Sin (y
erugth at aircraft due ts) antennas 1
ength at aircraft due to antenna 1
(I)
angle formed by the perpendicular of a line connecting
antenna 1 to 2 with the reference line
phase angle by which the current in antenna Z leads
current in antenna 1
By the samemethod:
al strength
al strength at airc
.An
where
and
Cos # Sin (y
far the azimuth angle y is given by:
(4)
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The quantities on the right of equattons (4) and (3) are known.
it is to be noted that1.1, and pi t are fixed by the geometry of
the antenna positioning. The fair of equation (3) suggests a
ivssible mechanical analogue for finch i the azimuth eagle v.
Figure Z shows the geometry which represents the azimuth
angle in terms of the fixed angles 01 and Alio and the Vari-
ables 1( andtwhich are detorm ed by-the signal ratios
IZ I
according to equa one (4) and (5).
3-4. Once having a value for v. equation (1) or CO yield* the
vertical angle co by use of an equation of the form:
(4)
The range cit the aircraft is determined from a knowledge of
the path length of the radiation from the transmitter to the re-
ceiver and the vertical angle * obtained by use of equation 6.
Thus far, only one-hop propagation modes have been considered.
3-3. The range r for the one-hop mode is given by ZRO. (See
figure 3.) Expressed in terms of?and the path length L. this
ttecomes:
r at t
-.1%41.11?
/ 1 L.
R
a,fige due to an
2L5 km :oins sin (4
do
(7)
(a/
Table 1 s a tabulation of the errors in r due to an error of one
degree its for different ranges and different heights of reflection h.
Table 1, i;rrors Range For One Degree Error
o as Function Of h
km) dr(km)
h 100 km
;Loo um 30 ?
0 km 400 km
4.43
7, 7
10.3
13.8
10. 1
1L9
18.0
1Z.
I S. 8
19.4
3500
18.5
21.1
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way of explanation. for the 2,000 km range, there is a 10.1
km error per degree error in few a height of reflection of
2,00 km and an 18.0 km error por degree error in for a
height of reflection of 400 km.
3-4. The fact that the receiving antenna is not at ground level
introduces an error if r is obtained using equation (7) directly.
The correct ground range is obtained (Se. figure 4. ) ii01731
ZR tan
ethers
J2,2 +
f +
4R
;au 0
e the actual path length
the correct height of reflection
= the height of reflection implicitly s ed
in using equation (8)
a height of receiving antenna
the path length from the receiving antenna
to ground maintaining the same ray direction
as from the point of reflection at h to the
ceceiving antenna
te rrris of central
ZRO,
where negletin
is given by:
where: 4R10.,
angles, the correct range I. given by:
Rea
eight of the receivi
the range
- (9)
tan
As a numerical exempt . let us c
60, 000. 0
I8.9 km
4044 km
6
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The correct r = 1911.0 km from equation (9
The incorrect r = 1919.0 km using equation (10). This is a
difference of 8 km.
5. No mention has been made of the errors due to the fact
that the ionosphere is not a smooth reflecting sheet. These
errors may be represented as uncertainties in Xiz, X13, and
will be minimized by averaging over a sufficiently large MUT! -
b e r of measurements.
4-0. GROUND-BASED NAVIGATIONWPM NT.
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7-O FOEM- FACTOR CONSIDERA,T/ONS.
7-1. The size and configuration of the space available in the
airplane for installation of System No. 2 equipment /eaves
much to be desired. The configuration of this space necessitates
packaging of the equipment in a manner which will contribute
undesirably to its weight. Also, the cockpit instrument panel
space available for control and operation of the system is less
than that required for the control unit of the ARC-34 equipment,
yet the System No. I equipment must perform functions of far
greater complexity than those involved in the operation of the
ARC- 34.
7-Z. These factors are of importance from an engineering stand-
point primarily because they tend to increase the difficulties of
equipment component design and because they necessitate the use
of form factors which are ill-suited to minimizing size and weight,
or to simplifying test and maintenance of the equipment. By way
of example, it may be mentioned that the space available is long,
narrow, and of irregular cross-section; accordingly it will probably
be necessary to incorporate a cast-magnesium-alloy "backbone"
as the basic support for system components. Space conforming
more nearly to equipment requirements would permit assembly
of the components in more conventional form, with a consequent
saving in weight of eight to ten pounds through elimination of the
backbone structure.
7-3. Preliminary estimates suggest that Sr stern o. 2 will employ
a total of about 300 vacuum tubes and transistors. The total
volume occupied will lie in the neighborhood of 2.5 to 3.0 cubic
feet, and the weight may be expected to approximate 60 pounds.
Average power input will be on the order of 500 watts, with
instantaneous peak values in the vicinity of 1500 watts. More
refined estimates of such data will be available for inclusion in
a future report.
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1
FROM RECEIVER _I
DETECTOR *,
OUTPUT
TO RECEIVER ,
AGC 4
CONTROL I
NAVIGATION PREAMBLE I
RECEIPT PULSE
? ? ? ?
L-O-Nr
OFF
8-ms
GATE
ON
OFF
THRESHOLD
DETECTOR
PROGRAMMER
4-ms
GATE
ON
OFF.
GATE
*8 PULSE
MODE
SELECTOR
TO ANTENNA
TRANSFER I
RELAY
L_ A
TX if i
--1
4 ON
MODULATION
FUNCTION
GENERATOR
t OFF
-
TO TRANSMIT EXCITER
AND
RANGE PULSE MODULATOR
PULSE
TIMING
ON
PROGRAMMER
*2
TIMING PULSES
12-ms PRF
RESET ALL
FUNCTIONS
GATE
SHIFT
ON
OFF
ON-OFF
4
RESET
ANGLE DATA
MODE GATE
AGC
AMPLIFIER
ON
GATE
OFF
? AMPLIFIER
RESET
AT MODE
GATE "OFF"
AZIMUTH
PROGRAMMER
OFF
ON
OFF
GATE
START
PULSE
STRETCHER
AT MODE
GATE 'OFF"
SAWTOOTH
GENERATOR ,
P.
AMPLITUDE
COMPARATOR
AND
PULSE GENERATOR
GATE
ON
ANGLE COUNTER
INTEGRATOR *I
OFF
ON
GATE
ANGLE COUNTER
INTEGRATOR *2
GATE
OSCILLATOR
AND
PULSE GENERATOR
ANGLE COUNTER
INTEGRATOR *3
GATE
GATE
DATA TRANSFER TO
COMMUNICATION SYSTEM
p.
FOR TRANSMISSION
TO BASE STATION
?
Figure 9A. Navigation Data And Timing Unit,
Block Diagram
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COMMUNICATION
SYSTEM
FUNCTIONS
NAVIGATION
PREAMBLE
RECEIPT
PULSE
DATA TRANSFER TO COMMUNICATION
SYSTEM FOR TRANSMISSION TO BASE
STATION
RECEIVER
TRANSMITTER
EXCITER AND
PULSE
MODULATOR
AGC CONTROL
NAVIGATION-
DATA AND
TIMING UNIT
RANGE
PULSE
TIMING
TRANSMITTER
POWER
AMPLIFIER
ANTENNA
TRANSFER
RELAY
AIRCRAFT
ANTENNA
RELAY CONTROL
Figure 9. Basic Airborne Navigation Equipment, Block Diagram
28
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CD
a
Wm RECEIVER
%?I?F OUTPUT
a
a
CNI
a
a
a
BI-PHASE DETECTOR
A ND
PULSE GENERATOR
-------------- -------------- ----- ------------
ON
OFF
?
TO RECEIVER
4
AGC CONTROL
FROM NAVIGATION
GATE
48 ms
ON
OFF
THRESHOLD
DETECTOR
PROGRAMMER
4-ms
GATE
ON
OFF
V
AGC
AMPLIFIER
4
RANGE?
PULSE GATE
(8TH PULSE)
MODE
SELECTOR
ON
OFF
?
TIMING CONTROL UNIT
GATE
OSCILLATOR
AND
PULSE
GENERATOR
ROUND-TRIP
RANGE COUNTER
ON
GATE
READ
OUT
-- _ _ _ ----------- _ _ ----- _ _ _ -- _ _ _ _ _ ______________________ _ _ _ _
Figure 8. Navigation Range?Data Unit,
Block Diagram
CECIZET
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INITIATE
NAVIGATION SEQUENCE
CRYSTAL OSCILLATOR,
PULSE GENERATOR
AND SCALER
PHASING
TO COMMUNICATION
SYSTEM FUNCTIONS
?
p F?i71 = 12 S
AND
?
GATE
POWER
AMPLIFIER
OFF
TO ANTENNA
CONTROL UNIT
TO PULSE
MODULATOR
A
SWITCH
TO R X
RANGE- PULSE
GENERATOR
NAVIGATION
PREAMBLE
START PULSE
TIMING
PULSES
04 GATE
6
FF
TX RANGE
PULSE
SEQUENCE
TO NAVIGATION RANGE-
DATA UNIT
TO ANTENNA
CONTROL UNIT
SWITCH TO TX
ON ANGLE ARRAY
TO TX EXCITER
PULSE MODULATOR
ANGLE- DATA
PULSE GENERATOR
ON
OFF
GATE 4
?
1 48 48!
128 MS 96 MS a4MS 1.i 96 MS 1.4os .4
()(2- 64.8 SEC. ??
BINARY COUNTER
-Sr
?
8333 CPS TO ANTENNA CONTROL UNIT
TO CONTROL ANGLE DATA ARRAY SWITCHING
RESET
Figure 7. Navigation Timing' 81
CCCIIET
control Unit (Ground Based), Block Diagram
nir
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COMMUNICATION
SYSTEM
FUNCTIONS
NAVIGATION
PREAMBLE
START
PULSE
NAVIGATION
TIMING-
CONTROL
UNIT
TRANSMITTER
EXCITER AND
PULSE MODULATOR
NAVIGATION
RANGE -
DATA UNIT
TRANSMITTER
POWER
AMPLIFIER
RECEIVER
AGC CONTROL
ANTENNA
CONTROL
UNIT
ANGLE DATA ARRAY
SWITCHING CONTROL
3
RHOMBIC ANTENNA
Figure 6 . Base-Sta on Navigation Equipment, Block Diagram
25
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Geometric interpretation Of Equation 3
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