DEAR ED:

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP67B00511R000100180043-5
• Release Decision: RIPPUB
• Original Classification: K
• Document Page Count: 1
• Document Creation Date: December 20, 2016
• Document Release Date: March 21, 2000
• Sequence Number: 43
• Publication Date: July 12, 1961
• Content Type: LETTER

Approved Fo&lease 2006/04/13: CIA-RDP67B00500010018004.3 , CO
July 12, 1961
The suggestion in letter (30 June 1961x, File 2.3.1.2)
is interesting, since the continuous belt avoids the intermittent sampling
problem associated with the old driftsight. Whether this will be very
accurate depends on two factors: (1) The degree of match which is
possible due to fore-aft angular distortion in the driftsight optics; and
(2) the time which the operator can spend making accurate fixes.
If a driftsight scheme can be considered, it might work as follows.
Assuming the driver is capable of setting the device to about 3-5%
accuracy, our gear would light an indicator whenever it was operating
uncaged and read more than 5% different from the driftsight V/h. The
operator would check that this driftsight vetting was as good as he could
do, and this would then run the system until the sensor again took over.
The operator would only have to set the driftsight whenever the indicator
came on, or whenever he felt cloudcover or other special conditions made
him more able to set in V/h. (These special conditions would have to be
determined by later experience.)
Since the "standby" V/h is a feature we require but have not yet
frozen in our V/h sensor, we would like to pursue this further.
Furthermore, the same sensor will be used in ELG's system, and, perhaps,
You'll find it valuable for II or other systems also. Therefore,
I'd appreciate it if you would let us know about: (1) The optical dis-
tortion; and (2) available operator time.
A third point to consider is whether the new driftsight can be
modified (by us, by you, by the manufacturer?), in terms of space avail-
ability. I assume it is a reimaging system and has an accessible inter-
mediate focus, but this should be checked, if possible.
I plan to take two weeks vacation 17-28 July, and would appreciate
it if we could discuss this when I return. Jules will be in the plant
while I'm away, in case there are any questions.
Best regards,
04x
cc: WHI
EPK
Cy 2 Mi. M 3"5
Approved For Release 2006/04/13 : CIA-RDP67B00511 R000100180043-5