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Groot, Jos 
  
  
Two 8 km long flight lines were chosen, each at 6000 m height, but at different azimuth angles. This should 
enable one to not only measure the size of the deformation, but also the direction. The radar was operated with 
VV polarisation. 
In 1998 two flights were performed to test the navigation. On 29 January 1999 and 3 February 2000 two 
measurement flights were carried out. In between some additional non-measurement test flights were performed. 
The 3 February flight benefited from the analysis of the preceding flights, and subsequent adjustments made to 
the radar and navigation systems. 
4 RESULTS 
Figure 2 shows a detail of one of the SAR images obtained, containing the dike with the corner reflectors. 
  
Figure 2. Detail of SAR image measured on 29-1-1999: dike with corner reflectors. 
The resolution of the images is derived from the corner reflector responses as about 1.2 m (azimuth) and 5 m 
(slant range). 
Figure 3 shows a typical example of the flight path (from the 10 cm accuracy data) of one of the runs of 29-1- 
1999. The 10 m horizontal distance criterion is clearly met. A remarkable feature is the oscillation, which is 
caused by the particular navigation implementation. The oscillation corresponds to about +1.3° azimuth angle 
variation, which is (partially) compensated by the antenna beam steering. 
  
International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B5. Amsterdam 2000. 307