Dean Merchant
3.3.1 LOW-ALTITUDE INVESTIGATION
Results of the low altitude investigation shown in Tab
determined by GPS to those determined by single phot
For details see Merchant [1996].
le 1. are in terms of comparisons of exposure station coordinates
o resection (SPR) based on in situ and on laboratory calibrations.
EAST NORTH UP
in situ lab in situ lab in situ lab
bias 0.033 0.045 -0.015 -0.028 0.004 1.671
std. dev. | about 0.064 0.094 0.038 0.105 0.051 0.044
mean
std. dev. | about 0.073 0.106 0.041 0.109 0.051 1.805
GPS
Table 1. Coordinate Discrepancies Between GPS and Single
Photo Resections Based on In Situ and Laboratory
Calibrations for Seven Photos at 1245 Meters Above the Ground [meters]
3.3.2 MID-ALTITUDE INVESTIGATION
The same aircraft and camera system were next flown over the mid-altitude range . Results of exposure station
comparisons are shown in Table 2. For details, see Merchant [1997].
EAST NORTH UP
in situ lab in situ lab in situ lab
bias 0.125 0.096 0.015 0.016 -0.005 1.417
std. dev. | about 0.148 0.152 0.177 0.185 0.065 0.073
mean
std. dev. | about 0.198 0.183 0.177 0.186 0.065 1.505
GPS
Table 2. Coordinate Discrepancies Between GPS and Single-Photo Resection Based on /n Situ and Laboratory
Calibrations for Nine Photos at 3070 Meters Above Ground [meters]
3.4 NATIONAL GEODETIC SURVEY EXPERIENCE [NGS]
The NGS of the National Ocean and Atmosphere Agency [NOAA] has also conducted in situ calibration tests in
cooperation with the United States Geological Survey [USGS]. See Merchant (1995). In this case, a pressurized twin
jet Cessna Citation aircraft and a Wild RC-20 15/23 camera were used. This aircraft is pictured in Figure 2.
For this experiment, the aircraft was flown at 5800 meters above the ground and cabin pressure was maintained
equivalent to that of 2000 meters. Between 10 and 14 widely spaced target images appear on each photo. Results of
comparisons of exposure station coordinates is provided in Table 3.
574 International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B3. Amsterdam 2000.
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