| Synthetic Aperture Radar(SAR) can achieve all day and all-weather observation for the ground targets without light and weather conditions restrictions. In recent years,micro moving target imaging and detection is a hot topic in the radar research field.Micro-moving target image often contains important information for the detection and identification, but micro-motion also causes the complex micro doppler modulation of the echo doppler which causes traditional target detection methods can not solve it.According to the characteristics of micro-moving targest, this paper proposes a new method of micro-moving targets imaging based on phase retrieval principle and the method of micro-moving targets detection based on the theory of compressive sensing.The major contents are as follows:Firstly, the basic principle of SAR imaging, the research status of micro-moving targets, the theory of compressive sensing, the development and application of the phase retrieval algorithm are introduced in detail. Then we achieve micro-moving targets imaging according to the the stripmap SAR system space geometric model, and the imaging characteristics of targets are analyzed. At the same time, we apply the theory of compressive sensing to the SAR micro-moving targets detection.Secondly, a method of micro-moving targets indication is proposed based on the theory of compressive sensing. Then we constrct the over-complete dictionary based on SAR imaging characteristics of targets with rotational micro-motion and the rotating three-blade rotor. Compressed sensing can be used to detect if there are some rational micro-motion targets in images through sparsity of radar target image in the hough transform domain. At last, we can confine the detection results and eliminate the false targets using the method of compensation correction.Finally, according to the doppler characteristics of vibrating targets with paired echoes, a method of vibrating targets focus imaging based on phase retrieval principle is proposed. First of all, several phase recovery algorithms are studied, and the possibility of applying the principle of phase retrieval to the echo data of SAR vibrating target is discussed. Then phase recovery algorithm is used for vibration target imaging. In thephase recovery algorithm, we can change the size of the support domain and the parameters of the filter to reduce the interference of the external information, improve the convergence of the iterative algorithm, and eliminate paired echoes of vibrating targets,which can help us get the focus high resolution image of the vibration target. |
