COMPARATIVE ANALYSIS OF DIFFERENT INSAR TIME SERIES MONI-TORING OF GROUND SUBSIDENCE IN SUZHOU WEST WATER SOURCE

PS-InSAR and SBAS-InSAR technologies are widely used in land subsidence monitoring. Due to the different technical principles, the monitoring accuracy of the two technologies is affected by the scattering characteristics of ground objects. In order to study the difference of the monitoring accuracy of the two technologies in the area of complex ground object scattering characteristics, this paper used PS-InSAR and SBAS-InSAR technologies to monitor the ground subsidence in the surrounding area of 20×20km² centered on 110 wells in the west water source of Suzhou. We used the measured data of the fiber optic monitoring hole SK01 in downtown Suzhou to correct the results of time-series InSAR monitoring. To compare the settlement results obtained by the two technologies, we selected the vicinity of No. 15, No. 48, and No. 98 wells and characteristic points in the suburbs and central areas of the city for time series analysis and perform accuracy analysis in the densely built area. The results show that the monitoring results of the two technologies in the study area are consistent and correlated, and the linear correlation coefficient R of the settlement rate of the high-coherence point with the same coordinates reaches more than 0.96. However, in the rapid settlement area, the SBAS-InSAR technology is more robust in solving, and the settlement rate of the central area of the settlement funnel on the west side of the water source is monitored to be between -43.2 and -30.0mm ·a^-1. In areas with weak ground scattering in the suburbs, the numerical deviations of the monitoring results of the two technologies are relatively large, and the deviation of the annual average settlement rate reaches 5.7mm ·a^-1, which is about 2 to 3 times that of other areas. In areas with strong ground scattering in the central areas, PS-InSAR can reflect the settlement difference between the building structure and the surrounding environment from a smaller scale.