THREE-DIMENSIONAL GROUND DEFORMATION MONITORING BY MULTI-TEMPORAL SAR IMAGES AND FEWER GNSS SURVEY RESULTS

Abstract

 Permanent Scatterers Interferometry (PSI) can measure accurately ground deformation along the radar line-of-sight (LOS) direction. To detect three-dimensional (3D) ground deformation, PSI results along two different LOS directions and GNSS survey data are integrated. However, in many cases in Japan, the GNSS data available for the analysis are limited to the data of the electronic reference points operated by Geospatial Information Authority of Japan. The geolocation of the points are approximately 10 to 20 km away from each other, and the data may not reflect the deformation of the area of interest. Thus, in this paper, we examined the approach to effectively estimate the 3D deformation around Niigata airport under the framework of the data integration. Furthermore, we selected Distributed Scatterers (DS) to increase the number of the analysis points and set the upper limit of the distance for matching analysis points in each LOS. We compared the estimated vertical deformation velocity with the velocity derived from leveling survey data, and the Root Mean Square Error (RMSE) was improved 2.4 mm/year from 4.0 mm/year. It was found that our proposal is effective for monitoring ground deformation even though the GNSS data available are far away from the area of interest.