An Experiment of GB-SAR Interperometric Measurement of Target Displacement and Atmospheric Correction

We made a ground-based synthetic aperture radar (GB-SAR) system and tested its interferometric SAR (InSAR) measurement on the displacement of a trihedral corner reflector with atmospheric correction in terms of humidity and range. The GB-SAR worked at C-band with the synthetic aperture length of 5 m. Fully-polarimetric images were obtained with resolutions of 25 cm in range and 0.32 degree in azimuth direction. Located 160 m away from the system, the reflector was moved from 1 mm to 40 mm toward the system during each acquisition. An atmospheric correction function was obtained in terms of humidity and range by analyzing the phase of several stationary targets. The result showed an atmospheric delay of 3 mm at 160 m range when humidity changed from 47% to 58%. After atmospheric correction, DInSAR error was less than 1 mm with the correlation coefficient of 0.9999 when compared with the actual displacements. We concluded that atmospheric correction should be reinforced somehow for most spaceborne InSAR applications.