The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B6b. Beijing 2008 
236 
Figure 6 Deformation Levels of the 2329 PS Targets (2004- 
2006) 
We expanded the existing solution to additional points by 
interpolation (Fig 7). 
Figure 7 Linear Deformation velocity of the all PSC (after 
interpolation) 
4. CONCLUSION 
Using the PS technique, we computed out the deformation level 
of the study area between the 2004-2006 with the InSAR 
generated DEM. The deformation rate of the 2329 PS targets 
are achieved. The velocity of the majority of them is below the 
O.lmm/year (Fig.7). During the processing, the single coherent 
pixel can be identified. In the large temporal and geometric 
baselines, only point wise targets carry targets carry useful 
phase information. In our experiment, the largest perpendicular 
baseline is 1338.81m (the limitation of the DInSAR is about 
less than 1200m). 
Most of the experiments of the PS technique were done in the 
urban region. Because of the PS targets is quite rare in the rural 
region. In our study, the PS is almost rockies around the 
mountains. For Tibet area, the PS targets is much less than the 
other place. The winter is lasted aboutt half of the yearlong. So 
the thick snow hat of the study area is one of the big problems 
for PS processing. 
Our study shows the probability of the PS processing in the 
rural region. While, the precision ground surveying data is 
invalid during our experiment. The more study should be done 
in order to confirm the results. Another remark is that for more 
than 30 SAR images, the step of unwrapping and model 
refinement could be done together that can remove the error 
from the incorrect phase unwrapping. 
ACKNOWLEDGEMENTS 
This work is support by National Key Basic Research and 
Development Program (973 program) under Grant 
No.2006CB701303. The SAR data is provided by ESA through 
Dragon Program with ID 4803 
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