Multi-pass Differential Radar Interferometry with the Aid of Gis

Differential interferometric synthetic aperture radar (DInSAR) has been increasingly used to monitor ground surface deformations due to such occurrences as underground mining, fluid extraction, earthquake and volcanic activities. However, temporal decorrelation has made it difficult to derive useful information from a single pair of repeat-pass satellite radar images for vegetated regions when the time span between image acquisitions is long. A methodology is proposed for monitoring ground deformation using multi-pass differential radar interferometry (MPDInSAR) with the aid of a Geographic Information System (GIS). In this approach, several radar images covering the same region from multiple satellite passes are grouped into master-slave pairs of short temporal baselines. These image pairs are processed individually by using spaceborne repeat-pass DInSAR to generate the results depicting ground deformation, which are then exported to the GIS. These displacement images are precisely geo-referenced, reclassified and combined using various GIS tools to produce a total displacement image over the entire period of time spanned by the multiple satellite passes. The MPDInSAR approach has been tested at the underground coal mining areas in eastern Australia. Ground subsidence due to mining has been monitored using L-band JERS-1 satellite images. The RMS errors of less than 1.5 centimetre has been demonstrated.