Study On Ground Moving Target Indication For Airborne/Spaceborne Radar

This dissertation is focused on the research of airborne/spaceborne radar's ground moving target indication (GMTI). It concerns the respects as, airborne dual-channel radar measured data, bistatic airborne radar, dual-satellite radar system in the same orbit and near distance, and space based sparse array scanned pattern interferometric radar. The key contributions are:1. A joint method of Doppler beam sharpen (DBS) imaging and signal subspace processing (SSP) is proposed to achieve GMTI for the airborne dual-antenna radar. The method SSP is used to precisely calibrate the two antennas' DBS images, because the error of the two channels changes pulse-to-pulse. So the GMTI is well performed in the difference image of the two calibrated images.2. A method to eliminate pollutions (i.e. strong targets and large clutter discretes) without loss of the limited samples is proposed, so that the estimated clutter covariance matrix is more close to the actual one, and the performance of space-time adaptive processing (STAP) is improved for the detection of smaller targets. Through theoretical analysis and processing the real measured data, the new method is proved to be right and feasible.3. A rule on bistatic airborne spectrum is discovered. It is a clutter characteristic of bistatic radars — approximate linearity, and is named as backside effect. In such an effect, the range-dependent clutter can be easily aligned, and STAP is to be more applicable to bistatics. Also, a new spectrum rotation aligning method is induced, which can gain a further performance improvement on GMTI when transmit-mainlobe and receive-mainlobe cover the same area but a little staggered.4. Based on the theory of matrix perturbations, the reason for good bistatic GMTI quality of parametric adaptive matched filter (PAMF) is worked out, and the rules of how to determinate the PAMF's order is proposed.5. In order to overcome the problem of blind speed in the dual-satellite radar's SAR-GMTI, a method is designed to work at three different operating frequencies. The minimum detected velocity (MDV) is decreased. By researching the SAR characteristics for moving targets, the three SAR difference-images of different operating frequencies can be used for target location.6. The GMTI of space based sparse array scanned pattern interferometric radar (SPIR) has been thought to fail when there are ambiguities in azimuth. However, when decomposing the point spread function matrix it would be understood that SPIR can work to some degree no matter whether there are ambiguities in azimuth. In addition, SPIR can get higher detection performance than that of constant space-time serial processing.