Research On Forward-looking Imaging Method Of High-speed Platform

Super-resolution method is an effective way to realize forward-looking imaging of high-speed platform.However,due to the high-speed movement characteristics of the radar platform,the traditional super-resolution imaging model is no longer suitable,and in practice,it also faces the problems of long range,low signal-to-noise ratio and high computational complexity caused by large range and wide super-resolution processing.In this thesis,the forward-looking accurate echo modeling and robust and efficient superresolution methods of high-speed platform are studied.The main work of this thesis is as follows:1.According to the scanning process of high-speed platform and the geometric relationship between radar platform and target,the mismatch of traditional imaging model under the high-speed movement of radar platform is analyzed.Combined with the Doppler phase information brought by the high-speed movement of radar platform,a more accurate echo model is established to provide a basis for subsequent research;2.The forward-looking super-resolution imaging method of high-speed platform based on sparse iterative covariance estimation is studied.The regularization parameters under sparse constraints are replaced with weighted square roots for iterative solution,which not only solves the problem of resolution improvement under the condition of long range and low signal-to-noise ratio,but also solves the problem of adaptive selection of regularization parameters;3.The fast super-resolution strategy of large range and wide imaging based on Doppler centroid correction is studied.Through the unified centroid correction of Doppler spectrum,the problem of high computational complexity caused by the existing superresolution processing strategy range by range is solved.While ensuring the imaging resolution,the two-dimensional forward-looking fast super-resolution imaging of highspeed platform is realized.The above models and methods are verified by simulation.The results show that the precise echo model proposed in this thesis can solve the mismatch problem of the traditional radar forward-looking imaging model.The proposed imaging method improves the resolution by three times when the signal-to-noise ratio is 15 d B,significantly reduces the computational complexity,and provides a technical way for high-speed radar platform forward-looking imaging.