International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part Bl. Istanbul 2004
especially in height. The RMS values in Z of strip 2 for
Raade, Moss and Soer are larger than the one for Torp. It can
also be seen that the network solution yields slightly better
results especially compared to those stations with a larger
PDOP.
While the improvements in accuracy are not very large in this
example, it should be kept in mind, that potential GPS errors
occurring at a particular reference station cannot be detected
if only one station is used. Therefore, the reliability of a
solution based on a single reference station is not very high.
By using the suggested network solution, which has already
found wide applicability in other GPS applications, the
reliability of the results can be significantly improved.
Having said this, it should also be mentioned that problems
concerning the GPS receiver in the aircraft can of course only
be detected and eliminated by using multiple GPS equipment
on board the plane.
RMS differences at
Used ref. | Strip PDOP | ICPs (two-ray-points)
Station sXY SZ
[cm] [cm]
Raade Strip 1 1,8 7,8 13.7
(8 — 30 km) | Strip 2 3,3 8,3 14,8
Moss Strip 1 1.8 8,1 14,1
(15-38 km) | Strip 2 3.2 8,4 14,5
Torp Strip 1 1,7 8,1 14,0
(20-50 km) | Strip 2 1,9 7,9 13,9
Soer Strip 1 1,9 8,2 14,6
(35-60 km) | Strip 2 3,3 8,9 15,8
Network Strip 1 - 7,9 13,8
solution
(8 — 60 km)
Network Strip 2 - 8,0 14,0
solution
(8 — 60 km)
Table 3: Results of direct 3D point determination at
independent check points (ICP) using two-ray
points and single reference stations and the
network solution, individual strips, image
scale 1:10.000
6 Conclusion
Direct sensor orientation has proven to be a serious
alternative to aerial triangulation. In this paper, a solution for
direct sensor orientation based on single reference stations
and on a GPS network was described, test results based on
the OEEPE test "Integrated sensor orientation" were
reported.
Our work resulted in RMS differences of 8 cm in planimetry
and 14 cm in height at independent check points obtained
with two-ray points an image scale 1:10 000 for single, short
baselines.
The network solution was shown to be slightly more accurate
than the single baseline solution, moreover the reliability of
the results is significantly higher.
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