for the most part, be acquired purely as byproducts of missile 
tests already programmed for the next few years. It is believed 
that as the satellite age unfolds, geodetic photogrammetry w111 
find important applications elsewhere. By way of illustration 
let us point out the recently aceomplished positioning of the 
island of Bermuda to an accuracy of 8, 21, and 10 feet in a 
rectangular X, Y, Z coordinate system. 
The importance of ballistic cameras as a calibration 
standard is derived from the fact that somewhat conflicting 
trajectories are obtained from the various tracking systems 
observing a given missile flight. Such inconsistencies reflect 
the systematic or bias errors made by the systems. The "bias 
factor" of a system may be defined as the ratio of the bias in 
a typical observation to the standard deviation of the obser- 
vation (the standard deviation, of course, is a measure of the 
purely random or accidental error). 
The ballistic camera is the only missile tracking system 
of high precision which can consistently produce data having a 
bias factor of substantially less than unity. Consequently, 1t 
ls also the only system of high precision for which Statistically 
meaningful and precise statements can be made concerning the 
absolute accuracy of the final product. High precision coupled 
With a low bias factor thus makes the ballistic camera uniquely 
qualified to serve as a calibration standard for other instru- 
mentation. It is therefore highly desirable in missile testing 
17