Positioning Parameters Estimation Of Moving Targets Based On Multi-satellite Radiation Sources

The target location system based on the external radiation source does not transmit the signal itself,but relies on the third party non-cooperative radiation source transmitting the signal and irradiating the target,and then regards the target reflected echo as a useful signal to estimate the positioning parameters.The working mechanism of the passive positioning system for the moving target based on the external radiation echo signal makes it have the advantage of "radio silence",so it has strong anti-interference ability and survivability,which is not achievable by the traditional target active positioning systems.The DOA,TDOA and FDOA are important parameters for target location.Whether the above parameters can be accurately estimated determines the accuracy of the target positioning system.As for the problem of low reliability and inaccuracy for the target positioning based on single-satellite radiation source,this paper proposes a multi-satellite collaborative passive target location system model through the external radiation source of multiple satellites.The main work and innovation of this article are as follows:(1)This paper aims at the inaccuracy of 2-D DOA estimation in non-Gaussian clutter scenes when the signal-to-noise ratio(SNR)is low,a 2-D DOA joint estimation method for moving target echo signals under the multi-satellite radiation sources named Improved Zero-Order Statistics Fractional Low-Order Cyclic Correlation(IZOS-FLOCC)is proposed on the basis of a uniform plane array,which focuses on the construction of DOA estimation statistics under the alpha stable distribution clutter environment.Firstly,the method uses a uniform plane array to establish the model of receiving signals.Then,because of there is no second-order and above second-order finite moments for the alpha-stable distribution clutter,the IZOS-FLOCC of the echo is constructed based on the cyclostationarity of the signal.Finally,the signal subspace of IZOS-FLOCC is obtained by the optimization method,and the 2-D DOA estimation is carried out through the MUSIC algorithm.This paper also deduces the Cramer-Rao Low Bound(CRLB)of 2-D DOA estimation of moving target echo signals in non-Gaussian clutter environment.The simulation experiments show that the IZOS-FLOCC method can effectively estimate the 2-D DOA of moving target echo signal based on multi-satellite radiation sources in non-Gaussian clutter environment,and its estimation performance is better than the signal subspace fitting algorithm.(2)In order to solve the problems that TDOA and FDOA estimation performance of moving target echo signals is greatly affected by noise and interference in Gaussian noise environment,this paper discusses the design method of TDOA and FDOA joint estimation statistics,and proposes a method based on Fourth-order Cyclic Cumulant Cross Ambiguity Function(FCCAF)and a method based on Four-Weighted Fractional Fourier Transform Fourth-order Cyclic Cumulant Cross Ambiguity Function(FWFCCAF)for the target echo TDOA and FDOA joint estimation,respectively.And complete the TDOA and FDOA joint estimation through feature extraction.The methods focus on the suppression of interference and noise in the parameter estimation statistics.Then,the data fusion methods and the estimation values of TDOA and FDOA are used to complete the distance and velocity estimation of moving target based on multi-satellite collaboration.Finally,the CRLB of TDOA,FDOA,distance and velocity estimation based on multi radiation source are deduced.Through simulation experiments,it can be seen that both proposed methods can effectively estimate the TDOA and FDOA of the echo signal as well as the distance and velocity of the target under multi-satellite radiation sources,and the estimated performance of FWFCCAF is better.