Baseline Optimization Design of Airborne Tomographic SAR System

Tomographic synthetic aperture radar (TomoSAR) imaging has shown great potential in the three dimensional SAR focusing in recent years. One practical challenge is that the spatial separation of the multi-pass system is always non-uniform and also the number of tracks is very limited, thus may leading to the focusing results deteriorate compared to the results with uniform baseline distribution. In practice, when the sampled signal does not meet Nyquist's law, the signal sidelobe obtained by non-uniform sampling in a certain range is lower than that obtained by uniform sampling. How to design the baseline distribution between flights to minimize the focused signal sidelobe to a certain extent is the primary consideration of the airborne system before data recording. In this paper, we proposes an iterative spatial disturbance - sequential quadratic programming (ISP-SQP) optimization method. We obtain the optimal baselines by using SQP as preliminary operation, and then add different disturbances to the center of the baseline sequence in space iteratively as the initial value of SQP until it converge to optimal value. The simulation data applied to this method demonstrate that the proposed method is more effective in obtaining lower sidelobe in TomoSAR focusing.