Echo Model Construction And Research On Imaging Algorithm Of Geostationary Satellite Based Bistatic Forward-looking SAR

Geostationary satellite based Bistatic Forward Looking SAR system separated from a transmitting platform and a receiving platform is a space-borne synthetic aperture radar,Which is a particular kind of passive bistatic SAR system.GNSS is used as the transmitter,while the receiver is mounted on the airplane.The airplane travels along a straight line and the imaging target is in the front.geostationary satellite based Bistatic Forward Looking Synthetic Aperture Radar system is benefited from excellent coverage characteristics,low cost and good safety.It is widely used in self-landing,self-navigating and battle field information acquiring.This paper focuses on the echo model,signal characteristics,general point spread function method,imaging algorithm,spatial resolution,and depth of focus.After investigated the current research status of spaceborne bistatic SAR deeply,a new echo model is proposed,and a modified imaging algorithm is proposed based on the echo model.The main work is as follows:1.An echo model of Geostationary Satellite based Bistatic Forward-looking SAR is proposed.According to the echo model,a two-dimensional spectrum based on the LBF algorithm and general point spread function are derived,and a detailed derivation process is given.The accuracy of the echo model is verified by the simulation results of the two-dimensional spectrum and the point spread function.2.The MSR algorithm is used to further improve the accuracy of the two-dimensional spectrum,which provides a basis for modified the imaging algorithm and also improves the final focusing effect.3.According to the echo model in this paper,the modified RD algorithm is proposed,and a Range curve correction method in the time and frequency domain is proposed,which improves the accuracy and correctness of range cell correction.The detailed imaging algorithm process is given,and the imaging algorithm is simulated.The simulation results show that the modified imaging algorithm can be effectively applied to the system.4.The spatial resolution and focus depth analysis of the final imaging results were performed to illustrate the imaging performance and limitations of the algorithm.This paper proves the feasibility and correctness of geostationary satellite based Bistatic Forward Looking SAR from the perspective of simulation,and it lays the foundation for the practical application of such radar systems in the future.