The Algorithm Design Of SAR/GMTI Radar

Synthetic Aperture Radar (SAR) characterized of day and night, all weather, which can generate two-dimensional high-resolution images of the targets over a long distance, so it is widely used in both civilian and military fields. With the further investigation into imaging radar, the higher demand is proposed, including real-time imaging and higher image resolution. In addition, since the modern war is a tri-dimensional war that is a union of the terrene, sea, air, space and electromagnetism, the radar with only one function can no longer satisfy the requirements of modern war, so we have to develop multi-mode radars. The joint work of SAR, GMTI and AMTI can not only achieve ground scene imaging, ground moving targets detection, tracking and imaging, but can also achieve AMTI(Air Moving Target Indication). So it plays a very important role in the modern war. This dissertation mainly studies on the radar real-time imaging, image resolution improvement and the joint work of multi-mode radars.The first chapter is mainly associated with the concept of synthetic aperture, then reviews the development history of SAR, introduces the existed research at present and the joint work of SAR/GMTI, at last concludes the whole contents of the dissertation.The second part describes the imaging mode and the theory of SAR, then discusses two classical imaging algorithms.In chapter3, since all kinds of the algorithms available which can correct the range cell curve however have a large amount of computation can not meet the demands of real-time imaging, an approach using FIR filter to correct range cell curve is proposed which better correct the range cell curve and obviously reduce the amount of computation and can meet the needs of real-time imaging system.The fourth part firstly describes the basic principle of stepped frequency signal, then integrates signal synthesis and motion compensation which better solve the problem that imaging of stepped frequency SAR due to the signal is sensitive to radial velocity.In chapter 5, a design of the parameters and algorithm for a multi-mode radar is made.The last chapter concludes all the contents of this dissertation and points out the problems left to be further discussed.