Nonlinear kalman filter phase unwrapping algorithm based on the terrain

Phase unwrapping is one of the key steps in InSAR data processing. In condition of steep terrain, excessive stripes reduce the conventional phase unwrapping algorithms’ implement, resulting in error propagation of unwrapping phase. Therefore, this paper presented a nonlinear Kalman filter phase unwrapping algorithm based on terrain. This algorithm uses local fringe frequency estimation as input control variable. Chirp-Z transform is added into Fourier transform in local frequency estimation, and this improves the unwrapping result accuracy. Results obtained with simulated and real data validate effectiveness of proposed method through analyzing and comparing with Kalman filter method, nonlinear Kalman filter method and quality map guiding method.