Remko Wicherson 
  
main advantage is that the camera records photo's on the chosen location, not displaced by a tilt of the aircraft. On 
the other hand, the determination of the camera projection centre is less accurate. 
  
strip 6 
  
strip 
strip 5 
  
  
  
Figure 2: Moerdijk test block. A block of five strips and 4 cross strips; 108 
XYZ-GCPs are marked with A. 
4.2 Data processing 
Data processing is subdivided in three parts: system calibration, processing GPS/Inertial system data to GPS/INS 
data and the photogrammetric processing. 
The system calibration takes two steps. First the shift between the GPS antenna and camera projection centre (GPS 
offset), as well as the shift between the IMU and the camera is measured tacheometrically. Next the misalignment 
between the IMU and the camera is determined by carrying out a specially constructed flight of a calibration site 
close to the test site. This calibration site is covered by 6 strips, 4 parallel and 2 cross-strips. Photo's of the site are 
captured and photogrammetrically processed to determine the position and attitude of the camera. These data are 
compared with the simultaneously recorded GPS/INS data. The difference in orientation is equal to the mean 
misalignment. 
To convert the GPS/IMU data to GPS/INS data, first the GPS data is processed. Comparisons between solutions from 
different GPS reference stations haven't been made, partially because of missing data from one reference station in 
the test field. Next, dGPS and IMU data are integrated into a GPS/INS solution. 
After scanning the photographs with a resolution of 15 um, all photo's are triangulated strip-wise on the DPW -770. 
Next the parallel and cross strips are adjusted. 
The bundle block adjustment program BLUH is used for connecting the GCPs to the photo block. It should be 
possible to use GPS/INS data in an adjustment program. However, BLUH is currently not able to process GPS/INS 
data in a combined adjustment. 
5 ANALYSIS AND TEST RESULTS 
5.1 Analysis plan 
The test block is specially designed for multilateral research possibilities. Due to the redundancy in high accurate 
GCPs and the presence of four cross-strips it is possible to create accurate and reliable reference data. Since the 
reference data is used for evaluating different research scenario’s as well as the quality of the POS/DG data, it is 
  
974 International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B3. Amsterdam 2000.