Integration of GPS, radar interferometry and GIS for ground deformation monitoring

Dense continuously-operating networks of GPS receivers (CGPS) have been established in many parts of the world in order to monitor ground deformation due to earthquakes and other activities. However, it has been found that the CGPS is still NOT dense enough to monitor some phenomena, e.g. volcano and ground subsidence due to mining. Therefore the authors propose to combine GPS with radar interferometry (InSAR) and GIS so that CGPS can monitor small scale deformation as well. The methodology is to use CGPS to estimate the differential tropospheric delays and apply these estimations as corrections to the radar interferometric results in order to ensure sub-centimetre accuracy. The corrected InSAR results are exported to the GIS so that the ground deformation can be interpreted along with other spatial information such as aerial photos and mine plans. Data from both the SCIGN and GEONET have been employed to test the tropospheric estimation process. InSAR results for monitoring subsidence due to underground mining in an Australian region have been interpreted with the aid of the GIS.