Study on the Methods of InSAR Baseline Estimation

Baseline is an important parameter of the process of InSAR (interferometric synthetic aperture radar), which directly influences the accuracy of the ultimate DEM generated. In this paper, firstly, the relationship between positioning and deformation measure accuracy and baseline error was analyzed. Secondly, three classical baseline estimation methods, which are the method based on precise orbit data, the method based on fast Fourier transform (FFT) and the method based on control points, were compared. Meanwhile, three combination projects of baseline estimation methods with higher accuracy were also studied. Finally, an experiment was done with the ERS1/2 image pairs located in Shandong province, and the DEM generated by three combination methods and SRTM DEM were compared. According to that, the conclusions can be obtained as follows: The baseline between two images isn´t a constant value, which is changed with the variation of coordinates of the images; The accuracy of DEM generated by the last combination project is improved about 50 m than that obtained by the method based on precise orbit data. Therefore, it is proved that the combination projects of baseline estimation methods proposed in this paper are available.