1 
I. PURPOSE OF THE PAPER, 
In aerial survey, the measurement and determination of the functions performed during survey 
flight is a field which is lagging behind as compared to many other operations in photogrammetry. 
Consequently, survey flight to produce good-quality aerial photography is a bottle-neck in many 
cases, and survey navigation is a field to which the photogrammetrist - generally speaking - 
feels rather strange. The determination of camera station elements in flight as auxiliary data 
for aerial triangulation has received considerable attention in publications but their actual 
application has been extremely limited. 
The state of the art in modern flight and space and navigational technology is such that many 
functions can be performed with high accuracy. For some of them, system components are 
available in great variety and it would be possible - today or in the near future - to obtain 
nearly every desired accuracy if the user, the photogrammetrist, would find it worth while to 
have it developed and constructed at his cost. For some of the desired functions this can be 
done by relatively simple means; for other functions, complicated and sophisticated instru 
mentation is required to produce a given desired accuracy. 
To judge the economical justification of the use of the many possibilities we have at our 
disposal today, one should look at the medal from two sides. On the one hand, it is necessary 
to review what photogrammetric results can be obtained by determining flight parameters 
with varying accuracy. For a number of flight functions, this is done for this congress by the 
invited paper for Commission III, H.G. Jerie, Techniques, evaluation and applications of 
auxiliary data in aerial triangulation. On the other hand, there is an obvious limit to the 
economy if flight functions can be determined with high accuracy only against high cost. 
It is the purpose of this paper to assist in optimizing photogrammetry - both survey 
navigation and aerial triangulation - by presenting a review of what is the order of magnitude 
of cost one has to pay for flight functions performed with various given accuracies.