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Introduction - This paper is concerned with the Analytical Photogrammetric , 
Positioning System (APPS). Photogrammetric instrumentation is quite often 
rather complex, particularly with the increasing use of digital components. 
It is apparent, however, that there are many applications of the principles, 
of photogrammetry which use relatively simple and low-cost components. 
The APPS, developed by the U.S. Army Engineer Topographic Laboratories 
(USAETL), is an example of such an application. The APPS is consistent with 
the topic of this symposium because the system contains digital components and 
utilizes a programmable digital calculator. While the APPS was originally 
conceived and developed to satisfy a military requirement, there are 
applications apart from the military whereby the concept and techniques 
of the APPS can be utilized. Extensive tests conducted have shown the 
system to be reliable, versatile and relatively inexpensive.