Performance analysis and simulation of 3D information deriving from InSAR with different baselines

Interferometric Synthetic Aperture Radar (InSAR) can derive accurate 3D information with image acquiring all time and all weather. But the accuracy of derived 3D information is heavily determined by the length of perpendicular baseline. We know that the longer baseline is, the more accurate Digital Elevation Model (DEM) can be derived in condition of other parameters are the same. Meanwhile the phase unwrapping is more difficult and the processing of InSAR is getting more complicated. Especially the length of baseline cannot longer than critical baseline. On the contrary, if the baseline is shorter, the processing of InSAR is easier, but the accuracy of derived DEM is lower. In order to show the performance of 3D information deriving from InSAR with different baselines, interferograms of InSAR with three different baselines are simulated and 3D information are derived in this paper. The frequencies and the coherence maps of their fringes are apparently different. The non-fuzzy height value and critical baseline are deduced to analyze the impact of baseline to InSAR performance theoretically. With the experimental results and the theoretical analysis, the facts in processing difficulty and accuracy for single baseline InSAR in mountainous areas are demonstrated, as can explain why the multi-baseline InSAR technique should be adopted to derive accurate DEM in mountainous areas robustly.