CFAR Detection Of Space-based Bistatic Radars Based On The Gerschgorin Circle Theorem

Space-based bistatic radar is an emerging radar system,which has been included in the key development plans of many countries,and has been applied in lunar surface observation,ground moving target recognition,radar warning,etc.But in a complex background environment,clutter is often non-uniform and non-stationary.Therefore,modeling the clutter as a simple and single distribution no longer meets the conditions of constant false alarm detection,and it cannot guarantee that the reference unit and the unit to be detected are independent and identically distributed,which leads to the problem of degraded detection performance.For this reason,In this paper,clutter modeling and constant false alarm target detection of space-based bistatic radar system are studied by analyzing clutter amplitude fluctuation statistical model,clutter simulation method,radar signal sampling model,target detection method and the Gerschgorin circle theorem.The main contents are:(1)The basic theories and methods related to the thesis are discussed.Firstly,the statistical model of clutter amplitude fluctuation and the clutter simulation method are analyzed according to the radar signal model.Then,the classical radar target detection method is discussed,the necessity of constant false alarm rate(CFAR)is analyzed,and the parameters of unit average constant false alarm detection are given.Finally,the Gerschgorin circle theorem and its application are described.(2)Then the clutter scattering unit segmentation method of the monostatic radar can be applied to the space-based bistatic radar system,thus the clutter scattering unit segmentation method of the space-based bistatic radar is obtained,and the space-based bistatic radar system is derived in detail The method of solving the equidistant ring of lower clutter.Then,the conversion relationship between the transmitter and receiver coordinate systems and the conversion relationship between the radar and antenna coordinate systems in the space-based radar geometric scene are analyzed.Next,this pater analyzes the influence of earth rotation and clutter Doppler frequency on space-based radar modeling.Finally,the clutter echo signal of the space-based bistatic radar is obtained,and the clutter numerical simulation result under a certain parameter setting is obtained.(3)Finally,the problem of the CFAR detection of bistatic space based radar(B-SBR)is addressed under the background of strong and non-homogeneous clutter.We propose a novel and simple CA-CFAR-like(CA-CFAR-L)detection method based on the Gerschgorin circle theorem for B-SBR.First,we investigate the potential of a novel test statistic T_CA-CFAR-Lexhibiting better properties about discrimination and CFAR using Gerschgorin circle theorem,and the test statistic T_CA-CFAR-Lis constructed as the ratio of the sum of the Gerschgorin radii of the covariance matrix of cell under test(CUT)to the sum of the Gerschgorin radii of the mean covariance matrix of the reference cells.Secondly,we investigate the CA-CFAR-L detector for B-SBR using the constructed test statistic T_CA-CFAR-L.Under the background of the K-distribution clutter model and the clutter model for B-SBR respectively,we verify the performance of the proposed CA-CFAR-L detector,the LE mean matrix CFAR detector and the FFT-CFAR detector.The simulation results demonstrate that the detection performance of the detector is better than the LE mean matrix CFAR detector and the FFT-CFAR detector under K-distributed clutter and the space-based bistatic radar clutter environment,and the proposed method has less computational complexity.Future research on radar target detection performance will provide an important theoretical basis and new ideas.