The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part Bl. Beijing 2008 
252 
3 SAR images for ERS data and two-pass method using two 
ASAR images plus an external DEM for Envisat data. 
Figure 1 The TM image of Tangshan test site 
Mission 
Track 
Frame 
Orbit 
Date 
Perp. 
bas el me/m 
Temporal 
baseline/d 
ERS 2 
175 
2799 
23710 
19960127 
8 
-625 
ERS 2 
175 
2799 
13055 
19971019 
0 
0 
ERS 2 
175 
2799 
16061 
19980517 
413 
0 
211 
0 
ERS 2 
175 
2799 
26582 
20000521 
150 
735 
Table 1 ERS 1/2 SLC SAR data 
Mission 
Track 
Frame 
Orbit 
Date 
Perp. 
baseline/m 
Temporal 
Baseline/d 
ENVISAT 
268 
783 
9841 
20040117 
130 
-240 
ENVISAT 
268 
783 
13348 
20040918 
0 
0 
ENVISAT 
268 
783 
20863 
20060225 
92 
515 
Table2 Envisat SLC ASAR data 
4. INTERPRETATION OF INSAR RESULTS WITH 
THE AID OF GIS 
After reviewing the available software for InSAR processing it 
was decided that DORIS InSAR Processor developed by the 
Delft Institute for Earth-Oriented Space Research (DEOS), 
DORIS is free software (for non-commercial scientific purpose) 
that runs on UNIX/Linux platforms. [Kampes, B., 1999].It can 
generate interferometric products and end-products from Single 
Look Complex radar data provided by ESA. Scenes generated 
by ERSI, ERS2 and Envisat satellites can be processed. 
Interferogram unwrapping was performed using the SNAPHU 
software developed by Curtis W. Chen [Curtis W. Chen ,2002] 
and integrated as module with DORIS. 
The differential InSAR results were exported to and 
post-processed in the GIS. The mine subsidence regions can be 
seen clearly and the color coding indicates the magnitude of 
subsidence, as shown in Figure2. A further advantage of using 
the GIS is that ground deformation can be analyzed and 
visualized in various ways.