The Study On Imaging Technology Of Bistatic SAR With A Stationary Receiver

Bistatic Synthetic Aperture Radar with fixed receiver is one operating mode of bistatic SAR. Its synthetic aperture is formed by the motion of transmitter. Compared with the traditional satellite and airborne systems, the bistatic SAR has the advantages of bistatic imaging systems. What's more, it is of low cost and its complexity of imaging process is almost the same with single-station systems. Such a system could also perform interferometric applications by placing several receiving subsystems in slightly different positions. So the new system has a bright future of wide application. This dissertation sets up a geometrical model for the system and analyzes the characteristics of the range cell migration. Based on this, the paper conclude that the doppler frequency parameter form targets of different azimuth locations change with their positions. This conclusion provides theoretical basis for how to choose imaging algorithm. According to the structure of the system, the paper analyzes the range and azimuth resolution of the system and also studies how the space resolution changes with the target position in the imaging field. These work provides the basis for analyzing the imaging result.This dissertation analyzes the principles of fixed-receiver bistatic SAR and the characteristics of the imaging process. Based on the construction of the model of the system and analysis of the characteristics of the range cell migration, an improved NLCS algorithm is deduced to correct the influence of the difference on the range cell migration. The change of the Frequency Modulation (FM) rate in azimuth direction is analysed in detail. Then an extended NLCS algorithm is proposed to improve the focusing quality of the FM rate. The higher accuracy nonlinear perturbation function of the proposed algorithm are also analyzed in the paper. Finally the effectiveness of the algorithm is validated by simulation.In the dissertation, the multipath propagation effect caused by multi scatter environment is considered, and a novel target detection approach based on time reversal process is presentsed. By using the spatial reciprocity of the environment, the transmitter transmits the received signal in a reversed sequence, which makes the signal focused at the target position, thus the range and azimuth parameters could be acquired. By simulation, the excellent imaging performance and anti-noise capability of the time acquired approach in complex environment is validated, and this could be used as a reference for target imaging problems in complex detection environment.