Research On SAR-GMTI Based On DPCA

Synthetic aperture radar ground moving target indiction(SAR-GMTI) had been an important application within the field of radar as the radar imaging technique improving rapidly. Scine using multiple channels, multi-channel SAR can obtain more echo information, which had been the main and hot research in SAR-GMTI field after the single-channel SAR.. And now, it has got a breakthrough in applition of military monitor successly.The tecniques proposed based on multi-channel SAR include Displaced Phase Center Antenna(DPCA),Along-track Interferometry SAR(ATI-SAR), Space Time Adaptive Processing(STAP) and Multi-Input Multi-Output(MIMO). Among them, the researchs on DPCA and ATI-SAR are. However, the STAP and MIMO are theoretically feasible but not in practice. Up to now, the DPCA and ATI-SAR are still the most effective detection approach in field of multi-channel SAR-GMTI, and the improvements of them have never stopped.DPCA and ATI-SAR have the similar physical device of data acquisition, but apply different data processing methods. The researchs on DPCA or ATI-SAR are focused on complex image domain. DPCA utilizes the magnitude of clutter cancellation to detect targets while ATI makes use of the interferometric phase. Although their technical route are determined, the supporting technologies are not complete. For example, the advantages,disadvantages and limiting factors of DPCA and ATI-SAR are unknown from beginning to end. Besides, the distribution of interferometric phase and magnitude had been investigated frequently while the rearches on the distribution of DPCA magnitude are little. That limits the application of adaptive method on moving target detection based on DPCA. In addition,the detection performance of DPCA and ATI-SAR are not very good because of channel imbalance and platform crab, therefore they need a further improvement.According to the research status of DPCA and ATI-SAR, the following works had been done in this thesis. Firstly, a modified dual-channel complex data model is given, then the limiting factors and detection performance are analysised based on the modified model. Secondly, the distribution model of DPCA magnitude are stuied in different terrain types and number of looks, meanwhile, the estimation of parameters are also given. Thirdly, based on the difference of region correlations between regions that targets are present and absent, a improved DPCA weighted by region correlation ratio is proposed, and this approach is insensitive to channel inbalance and the group shift of interferometric phase. The experiments with simulated data and real data all demonstrate that the performance of weighted DPCA is better than traditional DPCA.