| In recent years,electronic jamming methods emerge in an endless stream,which interfere with radar from multiple sources and multiple directions,seriously affecting the detection performance of radar,resulting in limited anti-jamming performance of a single radar,and cooperative detection of multiple radars has become a research hotspot.Bi-static and multi-static SAR can observe targets from more angles and show great potential in anti-jamming,which is an important cooperative detection method.In this paper,researches have been made on the imaging,location,false target suppression of bi-static and multi-static SAR,as well as on the design of collaborative anti-jamming simulation platform.The main works of this paper are as follows:(1)The working principle of Range Doppler(RD)imaging algorithm is deeply analyzed,the SAR model of ship target is established based on strong scattering points.Then,construct as well as simulate the radio frequency jamming,noise frequency modulation jamming,false target deception jamming and intermittent jamming to hinder SAR.(2)The target’s echo formula in bistatic SAR is established.The RD imaging algorithm of bistatic radar in shift-invariant parallel flight mode,shift-invariant squint mode and shift-variable mode is deeply simulated and compared with the self-focusing imaging algorithm based on entropy minimization.The results show that the self-focusing imaging algorithm accurately compensates the movement deviation of the target’s range through the high-order phase compensation function,so it is more suitable for SAR imaging in large squint angle and shift-variant mode.(3)The targets’ positioning technology is studied deeply.The Maximally Stable Extremal Regions algorithm is used to extract pixel position of the target from the SAR image.The range sum equation and equal Doppler line equation of bistatic SAR are derived.Newton iterative method is used to solve the range-Doppler equations,and the spatial position information of the target is obtained.Still,the effects of angle,velocity difference between transmitter and receiver,and oblique angle of receiver on target’s positioning accuracy is simulated and compared.The simulation results show that the angle of the dual base station has the greatest impact on the target positioning accuracy.(4)A multi-base SAR cooperatively false target suppression method based on target homology test is proposed.In this paper,the calculation method and implementation steps of target homology detection for multiple SAR images are derived.On this basis,the distance equations are established based on the spatial position relationship of the transceiver platform,jammer and false target.The interference source can be located by solving the equations.The simulation results show that the target homology check method can realize the spatial localization of real targets and false target,and suppress the distance deception jamming.(5)Author participates in the design and development of collaborative anti-jamming simulation platform.According to the platform’s future requirements for hardware in the loop simulation,an efficient echo signal generation method of target array and interference array is designed.Aiming at the real-time requirement of the simulation system,the multi-thread parallel processing method is adopted to accelerate the signal generation.The measured results show that the generation time of signal and interference under multi-thread is much lower than that of single thread,which greatly speeds up the running speed of the platform.Finally,the whole process of seeker searching,intercepting,tracking and destroying targets under various interference environments is realized on the co-simulation platform. |
