Research On Key Technologies Of Airborne Squint SAR-GMTI

With the increase of military demands,ground moving target detection(GMTI)has become one of the important functions to be implemented by modern radar in the military field.In order to realize detection,tracking and high-precision positioning of moving target,high-resolution large-squint real-time SAR-GMTI technology is studied.The traditional synthetic aperture radar can obtain the two-dimensional information of stationary target,i.e.azimuth and range.However,it cannot detect and image the moving target.To solve this problem,the moving target detection technology based on the sequential SAR image is studied to achieve the high probability detection of the moving target;and the research on track extraction technology based on multi-directional resolution and sequential images is carried out to achieve the situation awareness of moving target.This paper first established the system geometric configuration of a three-channel SAR system antenna,analyzed the performance of the forward squint SAR-GMTI in the case of the inclined antenna,and deduced the calculation formulae of the equivalent antenna aperture,minimum detectable speed and blind speed under this configuration.The system channel error and the three-dimensional motion error of the fighter is analyzed,and the influence of the channel equalization algorithm and motion compensation processing on clutter suppression and complex image coherence after channel cancellation is studied.Then,the algorithms for detection,speed measurement and positioning of moving target are designed.The DPCA principle is used for channel cancellation to complete the moving target detection;the effectiveness of the algorithm is verified through point scene simulation and surface scene simulation;the feasibility of the algorithm is verified through the SAR-GMTI processing of the measured data.Finally,a moving target imaging algorithm with higher resolution and a track extraction technology with higher accuracy are studied by introducing the sequential processing.A multi-channel TOPS SAR moving target echo model is established.The space-time adaptive processing method based on spectral compression is used to suppress background clutter and carry out imaging and detection processing on the moving target signals.Moving target imaging and tracking algorithms are proposed.Finally,the algorithm effect is verified through simulation.