Abstract for presentation at The 13th Australasian Remote Sensing and Photogrammetry Conference

High resolution SAR imagery for surface deformation assessment

  • Hsing-Chung Chang, School of Surveying and Spatial Information Systems, University of New South Wales, Australia, Australia
  • Dr Linlin Ge, School of Surveying and Spatial Information Systems, University of New South Wales, Australia, Australia
  • Prof Chris Rizos, School of Surveying and Spatial Information Systems, University of New South Wales, Australia, Australia

    • The geodetic information of the terrain can be measured using remote sensing techniques such as photogrammetry, airborne laser scanner (ALS) and interferometric synthetic aperture radar (InSAR). They are considered to be more cost-effective and complementary to conventional ground-based surveying methods, e.g. levelling and total stations. Differential InSAR (DInSAR) can be further used to monitor the dynamic change of the terrain by eliminating the topography from the interferometric phase.
    Our previous study has demonstrated the feasibility of using DInSAR for mining subsidence monitoring in the State of New South Wales, Australia, where the longwall mining technique is widely used at the underground mines. The phase fringes induced by mine subsidence have a typical feature of concentric circular or elliptical shape due to the longwall structure. The results showed that the phase fringes in the differential interferogram can be easily saturated due to the large amount of subsidence within a small spatial extent. The saturated phases make the interpretation of the subsidence rather difficult and erroneous. This can be eased by having the SAR data acquired with longer wavelength or shorter re-visit period.
    This paper uses 2-pass DInSAR with Radarsat-1 fine resolution (approximately 8m) SLC data to measure mine subsidence. The main objective of this study is to examine the benefits of having finer resolution data for DInSAR process. The results indicated that the coherence of the study area derived using Radarsat-1 fine resolution data is higher than ERS-1/2 results. Radarsat-1 fine resolution interferometry results showed that the usable baseline and temporal separation for maintaining sufficient coherence are much greater than ERS-1/2 data.
    The mine subsidence observed by DInSAR using Radarsat-1 data was validated against the ground truth data surveyed over the same period. The results indicated the improvement of accuracy by comparing to the results derived from ERS-1/2 data.

    Conference Organiser - ICMS Pty Ltd