Time Series PS-InSAR Using Small Data Set And Its Application To Surface Subsidence

Differential synthetic aperture radar interferometry(D-InSAR) technology was developed rapidly over the past twenty years. The disadvantage of conventional D-InSAR was emerging gradually with its development in theoretic research and expansion in applied field, for example, the temporal decorrelation and spatial decorrelation in long-time scales, error caused by the digital elevation model(DEM), the atmospheric effects etc. The permanent/persistent scatterer synthetic aperture radar interferometry(PS-InSAR) time series using small data set(TS-SDS) technology selects the pixels which are permanent/persistent scatterers. These pixels can keep high coherence in time scalse. So PS-InSAR can overcome the restriction in conventional D-InSAR from the temporal decorrelation, spatial decorrelation, error caused by DEM , the atmospheric effects, etc.Through analysing the differential interferometric phase, this thesis revealed that measuring height by InSAR, measuring land subsidence by conventional D-InSAR and measuring land subsidence by PS-InSAR is a deepening process for differential interferometric phase. This thesis applied PS-InSAR TS-SDS to picking up the mean velocities of land subsidence. The processing is selecting the high coherent PS pixels using the phase stability threshold method, computing and analysing systematically these PS pixels in space and time scales, rejecting the phase caused by DEM error, orbit error and atmospheric effects, and extracting the mean velocities of land subsidence. Combining to the experiments, this thesis applied PS-InSAR TS-SDS technology to the land subsidence in Tianjin Tanggu, selected 10 scenes PALSAR L-wave band image data from October 2007 to October 2009, obtained the average velocities of land subsidence in Tianjin Tanggu experimental area which is about 20km×20km, analyzed the center positions of land subsidence and the reasons for these land subsidence, got the D-value within 5mm/yr comparing this average velocities of land subsidence to historical data, and verified the feasibility of application this technology to land subsidence monitoring in Tianjin Tanggu.