gaps H AX Hay Haz
within strips 0 um 43 yum 80 um
across strips 28 um 47 um 72 um
diagonally
across strips 28 yum 49 um 71 um
The quoted results, which are accurate within 10 % and which
can be extrapolated to other assumptions about the precision
of navigation data, speak for themselves. It can be concluded,
that high precision orientation data may be sufficient for
small scale planimetric mapping. However, the requirements
for vertical accuracy could only be met by very high preci-
sion of orientation data, except for contour intervals of
20 m or larger.
5.4 Summarizing this preliminary simulation study it can be
stated that high precision navigation data - after appropri-
ate pre-processing - can be used directly for photo-mapping,
omitting aerial triangulation altogether. Also the applica-
tion for small scale mapping or thematic mapping may become
feasible. The vertical accuracy requirements, however, re-
main:critical.
On the other hand it is obvious that aerial triangulation
with auxiliary data will not be superseded easily. Therefore
intermediate solutions, applying simplified blockadjustment
procedures which would not require full point transfer, may
become interesting. Also, additional sensors, like laser pro-
filers, might further change the situation. It remains to be
seen what precision level navigation systems will reach in
near future.
6. OUTLOOK ON SENSOR ORIENTATION
It has been shown that the increasing accuracy performance
of navigation systems will have great economic effects in
photogrammetry, by making aerial triangulation practically
independent of ground control and,eventually, by reducing
aerial triangulation or making it obsolete altogether. There
is, in addition, a third field in which readily available
high precision orientation data may also have fundamental
impact. It concerns the orientation of sensors such as mul-
tispectral or other scanners, digital linear array cameras
of the MOMS or stereo-MOMS type, and laser- or microwave
terrain profilers. Such sensors are already applied for
remote sensing purposes. But the distinction will be less
sharp in future, as photogrammetry and remote sensing will
move closer together.
For obtaining geometrical accuracy the external orientation
of such sensors is most essential. Evidently inflight measu-
rement of external orientation data would be the most direct
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