Research On Bistatic SAR Moving Target Detection And Imaging Technology

In bistatic SAR,transmitter and receiver are placed on different platforms.Compared with monostatic SAR,the bistatic SAR has the capability of anti-detecting,anti-disturbing and high viability.It can also achieve forward/backward-looking imaging.This kind of systems can be applied in military and civilian fields.Bistatic SAR moving target detection and imaging technology is based on the bistatic SAR system,and this technology is designed to extract and detect moving target,such as vehicle and ship,from the background clutter through the signal processing methods.After the detection process,the moving target can also be well-imaged at the right position on the bistatic SAR stationary scene image.This technology can be applied in reconnaissance and surveillance fields with the complex electromagnetic environment.Moving target echo model,range cell migration correction(RCMC),parameter estimation,moving target echo extraction and integration from the clutter are the fundamental and key problems for bistatic SAR moving target detection and imaging.They are also the current important research topics in the world.Focusing on these problems,this dissertation carried out the theory analysis,method research and simulation experiments,includes1.The Doppler contribution determination method based on series reverse is proposed.The multi-solution problem of the stationary point that is caused by the coupling movements between the two platforms and the target can be solved by this method.The bistatic SAR moving target two-dimensional spectrum model has been constructed.This work provides a concise and accurate analytic expression for the research of moving target detection and imaging methods.2.The moving target RCMC method based on de-ambiguity keystone is proposed,and the range curvature correction function is constructed to align the range curvature.The echo envelope alignment problem of the noncooperative moving target can be solve by this method for bistatic SAR,and this is the fundamation of the moving target energy integration and detection works.3.The moving target detection method in Doppler frequency rate domain is proposed.Using the pre-balance and post-detection strategy,the moving target echo extraction and integration problem can be slove for bistatic SAR.Another one moving target detection method,which is based on the spatial-time joint integration process,is also proposed.The long observation time moving target echo can be integrated effectively by this method in very low signal to noise ratio situation for bistatic SAR.4.The moving target parameter estimation method based on pre-mismatched compression is proposed.The quantitative relationships between the mismatched compression result(including the position offset and the broadening width)and the Doppler parameters are derived.The noncooperative moving target Doppler and velocity parameter estimation problem can be solved by this method for bistatic SAR,and this is the foundation of the moving target azimuth relocated compression process.5.The optimal spectrum matching imaging method and the extended KT-NLCS imaging method are proposed.The noncooperative moving target spectrum estimation and echo two-dimensional spatial variation problems can be solved by these methods.Using these method,the moving target can be well-imaged in both translationally invariant and translationally variant bistatic SAR modes.The effectiveness of the above models and methods are verified by both theory analysis and simulation experiments.The experiment results demonstrate that these methods are able to achieve bistatic SAR moving target detection and imaging in various situations.