Research On Channel Equalization Based On DPCA For Airborne SAR/GMTI System

This dissertation studies the DPCA-based Synthetic Aperture Radar (SAR) ground moving targets detection and Channel Equalization techniques. Moving targets detection is a hot topic in the area of SAR, so many countries in the world are making great efforts to develop moving targets detection and relocation systems , and explore high efficient methods of moving targets detection and relocation. Channel equalization is an essential part in multi-channel SAR/GMTI system.The history and the development of SAR are reviewed first. With the analysis of SAR imaging principle and SAR reflection model for still target, SAR reflection model for moving targets is obtained. And the dissertation discusses the effect of moving targets on echoes and imaging. The dissertation deduces the echoes model which is backscattered from a pointlike moving object and received by a moving dual-channel SAR antenna. In addition, the DPCA algorithms in temporal domain and Doppler frequency domain of raw data are studied and compared. Based on the Improvement Factor (IF), the dissertation puts forward a performance analysis model of airborne dual-channel SAR/DPCA system. The dissertation puts forward the error analysis model based on the DPCA algorithm in Range-Doppler raw domain, studies the influences in the case of some errors and draws a conclusion: the performances of channel equalization are crucially influenced the performance of SAR/DPCA system. On the over basis, a channel blind equalization algorithm for dual-channel SAR/GMTI based on digital signal processing is put forward in the dissertation. The algorithm can estimate the amplitude and phase errors and compensate it. The simulation shows that the algorithm is implemented easily and cheaply between SAR/GMTI and antenna system. Another advantage is that the blind equalizer doesn't require any knowledge of the platform velocity and actual crab angle during the running operation.