and also the most convenient and most complete solution to 
the sensor orientation problem. A high precision level of 
orientation data will make such sensors directly acceptable 
for high accuracy photogrammetric application. A particularly 
interesting case will be laser profilers, or microwave scan- 
ners, the effective use of which depends absolutely on direct 
orientation data. Of course, interpolation principles may be 
applied due to high correlation of orientation elements at 
short time intervals. 
It is not the place here to go deeper into such problems. 
But it can be safely anticipated that the new navigation tech- 
nology will have a great influence on the effective utilizati- 
on of various sensors. It is quite likely that the conventio- 
nal image of photogrammetry will change fundamentally in a 
relatively short time. High precision navigation data will be 
a prime element in the realisation of such trends. 
7. CONCLUSION 
This paper has reviewed the situation photogrammetry is faced 
with in view of the progress in navigation systems. At pre- 
sent such systems are emerging which will give camera orien- 
tation data of very high relative precision. It is, at pre- 
sent, not quite certain which precision level will be obtai- 
ned. The optimistic expectations speak of camera positioning 
accuracy in the order of 1! m, down to the dm range.Attitude 
data are equally expected to reach angular precision in the 
order of 10-5 ro 1075 (or 6 to 0.6 mgon). If such accuracies 
are obtained by readily available equipment which is inex- 
pensive enough to become standard for air Survey flight 
mission the use of navigation data for orientation purposes 
will fundamentally change photogrammetric working methods. 
It has been shown - by simplified simulation - that the first 
step of utilizing navigation data can consist in considering 
them as auxiliary data for block-adjustment. The results in- 
dicate that navigation data of moderate accuracy are already 
highly effective in aerial triangulation greatly reducing 
the required number of ground control points to the sole 
function of establishing the reference coordinate system (and 
possibly to establish drift corrections). Mapping at small 
scales, medium scales and even large scales will be greatly 
affected. 
The second level of considerations regards the possibility 
that navigation data are accurate enough to be used directly 
for the orientation of photographs, avoiding aerial triangu- 
lation partly or completely. In first instance photo-mapping 
can be made more economic in this way. It remains to be seen 
how soon the very high precision requirements will be met. 
If the required level of precision will be reached 60 years 
of indirect determination of orientation parameters in photo- 
grammetry will be superseded and moved to a chapter in the 
history of photogrammetry. 
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