LINEAR PHASOLVER MEASURING ENGINE

• Document Type: CREST
• Collection: NGA Records (Formerly NIMA)
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78B04770A002900020015-4
• Release Decision: RIPPUB
• Original Classification: K
• Document Page Count: 5
• Document Creation Date: December 28, 2016
• Document Release Date: August 30, 2005
• Sequence Number: 15
• Publication Date: April 30, 1965
• Content Type: REPORT

Approved For Release 2005/11/21 : CIA-RDP78BO477OA002900020015-4
April 30, 1965
LINEAR PHASOLVER MEASURING ENGINE
STAT
The linear phasolver is an adaptation of the rotary phasolver.
The rotar hasolver is a standard product of thel STAT
STA4 hick measures shaft angles to a very ig accuracy,
19 its. It is used for remote measuring of radar antenna
angular position, theodolite pointing direction, and the
like. The linear phasolver uses the same principles as the
rotary phasolver-but for measuring linear dimensions to sub-
micron accuracy.
STAT
About two years ago, foresaw the need for a
new measuring engine, but he i not have a new machine to
tie it to. The shortcomings of the then existing yardsticks
were painfully apparent to him. The electronics were poorly
done with low reliability and uncertain drift. Some of them
were limited by the lead screw which had about reached the
end of its advancement in capability and was slow. Others
were limited by pulse detection and counting rate.
In looking around for a solution the best bet appeared to be
? the phasolver. It offered the following advantages:
(a) Determination of position was unique and un-
ambiguous and did not depend on counting pulses.
(b) It did not use a lead screw and the traversing
speed was thus not limited by the measuring speed.
(c) The electronics were well developed and had many
years of production and development debugging
behind them. The rotary phasolver electronics
were extraordinarily stale and free of drift.
Since linear measuring has some problems different than
STAT angular measuring, decided to get them
started with a feasibility study. It is a good thing
he did, too.
Declass Review by NGA.
Approved For Release 2005/11/21 : CIA-RDP78BO477OA002900020015-4
 Approved For Release 2005/11/21 : CIA-RDP78BO477OA002900020015-4
Linear Phasolver Measuring Engine
April 30, 1965
Page -2-
The phasolver works on the basis of determining the capacitive
coupling between metallic patterns on two glass plates, a
driver and a coupler, which slide along each other. The
coupler plate would be mounted on the stationary bed of the
measuring engine. The coupler pattern is merely straight
bars perpendicular to the direction of motion.
The driver would be mounted to the moving head of the measuring
engine and its pattern has a sinusoidal variation as shown
on the attached sketch. Two pattern designs were to be tested
in the feasibility demonstration.
The electronics measures the phase angle between electrical
RTAAT had as much trouble with the linear patterns
T asi had making the original rotary patterns. The
project was stalled for about 10 months waiting for good
patterns. The electronics were completed almost a year ago.
STAT After 0 finally made a good drier master pattern of
photographic emulsion on glass, made working atterns
STAT from the lImaster of deposited metal on glass. I lalso
made the coupler.
The test program is now under way to determine how good the
? phasolver really is. Test results are encouraging but,
of course, not complete and definitive. The electronics are
very stable and free of drift. When a measurement is set up
in the evening and left overnight, it is still registering
the same measurement to 1/10 micron the next morning.
(Room temperature is controlled to + 1?F and relative
humidity varies less than + 5%.)
The pattern appears to have a scale error of about 15 microns
over its 20 inch length. A scale error was expected and it
can be balanced out electrically. Also, there appears to
be a variation from pole pair to pole pair of from 1/4
micron to about 1-1/3 micron. They are not sure whether this
occurs in the test equipment or in the phasolver, but they
suspect the test equipment. They are presently trying to
pin down the source of the error. Probably the most
signals impressed on the driver and picked up by the coupler.
The phase angle varies with position, hence, the term
"phasolver." The entire problem has been the preparation of a
master driver pattern by
Approved For Release 2005/11/21 : CIA-RDP78BO477OA002900020015-4
 Approved For Release 2005/11/21 : CIA-RDP78BO477OA002900020015-4
Linear Phasolver Measuring Engine
April 30, 1965
Page -3-
STAT
STAT
STAT
?
encouraging news is that they can repeat a given measurement
an hour later and get the same reading to + 1/10 to + 2/10
micron. There is still quite a bit of checking to do, but
they expect that Test #2 "accuracy, resolution, and repeat-
ability' will be almost complete by the end of next week,
May 7, 1965.
director of Marketing for the
left to become president
effective about May 12, 5.
Attachment
Approved For Release 2005/11/21 : CIA-RDP78BO477OA002900020015-4
 Approved For Release 2005/11/21 : CIA-RDP78BO477GA002900020015-4
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Approved For Release 2005/11/21 : CIA-RDP78BO477OA002900020015-4
 Approved For Re se 2005/11/21 : CIA-RDP78B04770A 900020015-4
Approved For Release 2005/11/21 : ,CIA-RDP78B04770A002900020015-4
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