Research On High And Low Orbit Cooperative Dual-based Video-SAR Imaging And Target Tracking

The imaging time of a low-orbit SAR(Synthetic Aperture Radar)satellite for hotspots is usually in the order of seconds,but the revisit period is long,and it is impossible to continuously monitor the moving target in the observation scene for a long time.The re-interview period of the high-orbit SAR satellite is short,but The imaging resolution is low,and it is difficult to obtain a high-resolution target image in the imaging area.In order to solve the problems of high-resolution imaging and long-term continuous monitoring of moving targets in the observation scene at the same time,this thesis proposes a dual-base Video-SAR imaging system in which high and low orbit satellites work together.The main work carried out is summarized as follows:1.The parameter design of the high-low orbit coordinated dual-base Video-SAR system is studied,and the calculation process of parameters such as synthetic aperture time,imaging resolution,pulse repetition frequency,normalized noise equivalent backscatter coefficient,and frame rate is given as High-low orbit coordinated dual-base Video-SAR moving target imaging provides support.2.In order to realize the imaging of moving targets in the observation scene,highand low-orbit coordinated Video-SAR moving target imaging methods based on dual-channel and single-channel reception are studied respectively.Aiming at the dual-channel receiving model,imaging is performed using the dual-base RD algorithm,and the clutter suppression and moving target parameter estimation are performed by the DPCA(Displaced Phase Center Antenna)and ATI(Along Track Interferometry)algorithms,and the azimuth of the target is estimated using the minimum entropy Speed achieves refocusing of moving targets.Aiming at the single-channel receiving model,the time-domain subaperture BP(Back Projection)algorithm is used.Parallel operation of subapertures is used to increase the operation speed and reduce the algorithm complexity.The effectiveness of the two algorithms is verified by experimental simulation.3.In order to achieve real-time tracking of moving targets,high-and low-orbit coordinated Video-SAR moving target detection and tracking methods based on detection before tracking and tracking before detection are studied respectively.Aiming at the detection-and-tracking model,a dual-channel model is adopted,and the characteristics of the moving target are used for tracking.A joint multi-frame target tracking algorithm based on high-and low-orbit platforms is proposed,which uses dual-channel phase offset centers and targets along the track to interfere Detection and parameter estimation,using the echo framing characteristics of video SAR to detect and estimate the parameters of each frame of the target to achieve tracking of moving targets.For the method of tracking before detection,a directional weighting algorithm based on dynamic programming is used.Before weighting processing,the target's speed range and state number are used to estimate the possible motion range of the target to achieve target trajectory tracking.The effectiveness of the tracking technology before detection and the detection before tracking method are compared through simulation,and the advantages and disadvantages of the two methods are analyzed.