An Advanced Interferometric Synthetic Aperture Radar Stacking Technique for Long-term Deformation Monitoring

Kurzfassung

Measuring the long-term line-of-sight deformation using a multi-pass SAR data stack by standard persistent scatterer technique has been explored since the late 1990s. Research has been continuously conducted on increasing the data coverage at non-PS-rich areas. The recently developed SqueeSAR technique has validated the potential of extracting information from the distributed scatterers [1]. Modern SAR missions, like the German TerraSAR-X and the Italian COSMO-Skymed satellites, deliver SAR data with a very high spatial resolution of up to 1m compared to medium (10-30m) and high (3-10m) resolution SAR systems available so far [2][3]. This technique can benefit greatly from the higher resolution. This work gives a first presentation of an advanced interferometric SAR stacking technique using TerraSAR-X high resolution spotlight data. It pays particular attention on the critical problem of covariance matrix estimation. Studies are presented on adaptive averaging window strategies with Anderson-Darling statistical test. In addition, an adaptive multi-resolution defringe algorithm is introduced for topography and deformation induced local fringes removal which is a key issue for an accurate covariance matrix estimation. The result shows a great increment in the scatterer coverage than the standard PS technique . This increment is very helpful for natural hazard monitoring, e.g. volcanoes, since in most cases they occur in rural and mountainous areas where the population of distributed scatterers are extremely high.