29. Powell, R.W. 
United States 
AN/USQ-28* VERTICALITY VERIFICATION TEST 
This paper describes an operational test of the AN/USQ-28 Verticality Recording System. The planning and 
procurement of test materials, instrumentation, data reduction techniques, and resulting accuracies are 
presented and discussed. The primary objective of the test was to determine the accuracy of the fine verticality 
readout on the film format of each photograph obtained by the prime (aft) camera. The secondary objective 
of the test was to determine the relationship of the verticality between the prime (aft) camera and the slaved 
alternate (fore) camera. 
Using the procedures and equipment described, it is concluded that: 
]. The mean value of differences between the given and computed verticality data is -0.889 seconds for the 
x-tilt and & 23.045 seconds for the y-tilt. 
2. There is a 68.3 per cent certainty that the differences between the given and computed verticality values 
for any single photograph selected at random from the test mission will not deviate from the computed 
mean position by more than: 
x-tilt + 31.104 seconds 
y-tilt + 31.887 seconds 
3; When using the given verticality values with appropriate weights, as specified in the report, there is a 
mean value of differences between the known and computed ground control coordinates of: 
Latitude -0.027 seconds 
Longitude T 0.018 seconds 
Elevation +3.45 feet 
Easting +0.47 meters 
Northing -0.70 meters 
4. There is a 99.7 per cent certainty that the differences between the known and computed coordinates of 
any single ground control point selected at random will not deviate from the computed mean position 
by more than: 
Latitude 00.069 seconds 
Longitude +0.048 seconds 
Elevation + 11.88 feet 
Easting 1.26 meters 
Northing 2.10 meters 
The ranges satisfy TOPOCOM ’s horizontal and vertical accuracy requirements for large scale mapping. 
(1:25,000) 
S. The mean value of verticality differences between the prime and alternate cameras are: 
x-tilt T 3'37" 558 seconds 
y-tilt - 2'24* 448 seconds 
6. There is a 68.3 per cent certainty that the computed verticality differences, for simultaneous exposures, 
selected at random from the test mission, from the prime and alternate cameras, will not deviate from 
the computed mean value by more than: 
x-tilt + 33.274 seconds 
y-tilt + 34.770 seconds 
* Since the completion of this test, the AN/USQ-28 System is being discontinued as a US. Department of 
Defense imaging system. 
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