Research On Three-dimensional Attitude Reconstruction Method Of Space Target Based On Distance And Instantaneous Velocity

With the development of science and technology and the increasing frequency of space target activities,the detection and identification technology of space targets has become an important means to protect the interests of the people and national security.The threedimensional(3D)attitude of the space target contains important information such as the target's motion state and position coordinates,which provides a basis for radar target recognition and tracking.If the target attitude information at each moment can be determined,the target motion state can be determined,which can then be used to provide data support for subsequent judgment and evaluation.Therefore,the study of 3D attitude reconstruction algorithms for space targets has important practical significance.In this paper,in the context of the basic theories related to the 3D attitude of space targets,the time-frequency analysis method of space targets and the 3D attitude reconstruction algorithm of space targets based on the target's one-dimensional distance sequence and instantaneous velocity are deeply studied.The specific research content of this paper is as follows:(1)The scattering characteristics of space targets are studied.The definition of the 3D attitude of the space target studied in this paper is explained.Based on two scattering center models,Three kinds micro-motion forms of space targets are analyzed.the micro-motion characteristics of the target scattering center are verified by electromagnetic simulation data.(2)The principle of the classic time-frequency analysis methods: short-time fourier transform(STFT)and Wigner-Ville distribution are introduced.Due to the low timefrequency resolution or serious cross-terms in the classic time-frequency analysis algorithms,Two super-resolution time-frequency analysis methods based on iterative adaptive(IAA)and sparse Bayesian learning(SBL)sparse reconstruction algorithms are studied,the principle and formula of the super-resolution time-frequency analysis method are derived,the simulation experiment verifies that the time-frequency resolution of the two superresolution time-frequency analysis methods is higher than that of the traditional timefrequency analysis method.(3)Based on the problems of the super-resolution time-frequency analysis method: 1)poor aggregation of time-frequency analysis results;2)Long operation time.The sparse parameterized time-frequency analysis method based on the time-varying autoregressive(TVAR)model is studied,and the sparse reconstruction algorithm based on fast variational sparse bayesian learning(FVSBL)for solving coefficients of TVAR is proposed.and the process of solving model coefficients is derived.Through the analysis and comparison with the least square method and SBL algorithm to solve the TVAR model coefficients,it is verified that the FVSBL algorithm not only realizes the sparse solution of model coefficients of TVAR.but also reduces the computing time.Compared with the STSBL and STIAA algorithms,the sparse parameterized time-frequency analysis method based on the TVAR model has higher time-frequency resolution and shorter calculation time.(4)The 3D attitude reconstruction algorithm of space target based on the target's onedimensional(1D)distance and instantaneous velocity sequence is studied.The estimation method of obtaining a high-precision 1D range sequence based on the iterative adaptive algorithm(IAA)and instantaneous velocity estimation method based on the time-varying coefficients of the TVAR model are studied,and the correct correlation of the onedimensional range and the instantaneous velocity sequence is realized based on the Kalman filter respectively.Aiming at the problem that the two-step reconstruction algorithm based on singular value decomposition(SVD)using only 1D distance sequence is restricted by radar emission bandwidth and arbitrary rotation matrix ambiguity,This paper proposes a space target 3D attitude reconstruction algorithm based on distance and instantaneous velocity,and analyzes the two types of scattering centers separately,and uses electromagnetic simulation data to verify that the proposed algorithm can reconstruct the target attitude with less error than only using distance information based on SVD's two-step reconstruction method,and the problem of arbitrary rotation matrix blurring is avoided.