angular accuracy (in radians) by division by the focal length of 
the camera. With a camera of 300mm focal length, for example, 
3 microns amount to 1 x 1072 radians or about 2 seconds of arc. 
It follows that with good geometry, a pair of 300mm ballistic 
cameras are capable of providing positions accurate to the order 
of l part in 100,000 of the range from the cameras. Even higher 
accuracies are possible when more than two cameras are employed. 
Since the plate measuring accuracy is essentially independent of 
focal length, it is obvious that ballistic camera accuracies may 
be increased by the use of longer focal lengths. It appears from 
considerations of field of view, stability, atmospheric shimmer, 
and versatility that the practical upper limit for focal lengths 
for ballistic cameras would lie somewhere between one and two 
meters. Since improved photoprocessing methods and measuring 
instruments are expected to increase plate measuring accuracies 
to about 2 microns, and perhaps ultimately to 1 micron, the 
upper limit to potential photogrammetric accuracies in missile 
work is in the neighborhood of 1 part in 500,000 (0"%4) to 1 
part in 1,000,000 (0%2). 
As indicated at the outset, one of the major functions of 
the ballistic camera system at the Atlantic Missile Range is to 
Serve as a standard for the evaluation and calibration of tracking 
and guidance systems. The data required to accomplish this 
mission are obtained not only from missile tests but also from 
Specially designed aircraft tests. In fact, several hundred 
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