Research On Joint Estimation Method Of Multi-parameters Based On L-shaped Array

Along with the development of the times and the progress of science,it is more and more important for array signal processing technology in radar and mobile communication.As a crucial research direction in array signal processing,Direction of Arrival(DOA)estimation has been applied in fields such as wireless communication,navigation and positioning,and radar detection.Compared with the traditional 1-dimensional parameter estimation,2-Dimensional Direction of Arrival(2D-DOA)estimation and joint multiparameters estimation are more widely used.In complex practical environment,signal sources are highly correlated or even coherent due to interference factors such as multipath propagation,especially in underwater environment.This thesis studies 2D-DOA estimation of coherent signal sources.And multi-parameter estimation of signal is closer to practical application.The working frequency range of ground penetrating radar is between 1M～1GHz,so the improved propagation method is used to analyze the time-frequency domain data of signal obtained by detection system,and 2D-DOA angle and frequency of signal source are estimated at the same time.In the simulation analysis,the parameters of 1M～3MHz signals are estimated,and the results verify the effectiveness of algorithm.The main research content of this thesis as follows:(1)The 2D-DOA estimation of coherent signals under an L-shaped array structure is studied.The algorithm utilizes the stronger correlation between signals in the time and spatial than noises.According to the special properties of the Toeplitz matrix,the algorithm reconstructs the multiple Toeplitz matrix based on time-space to achieve the purpose of decoherence.Combining the ESPRIT algorithm,the azimuth and elevation of the signal are obtained.Compared with other Toeplitz matrix reconstruction algorithm and ESPRIT algorithm,the 2D-DOA estimation of this algorithm has smaller RMSE and higher POR under low SNR.(2)An improved propagator method(PM)for two-dimensional DOA and frequency joint estimation is studied.The propagator method constructs a propagation operator by splitting the matrix,without complicated eigenvalue decomposition or singular value decomposition operations,but by performing multiple operations on the propagation operator to obtain the noise subspace,to quickly obtain the angle and frequency information of the signal source.The traditional propagator method needs spectral peak search,and the improved propagator method has no use for spectral peak search.Calculate the covariance matrices of the X-axis and Y-axis in the L-shaped array and the whole array respectively,and then the propagation operator containing different information is obtained by dividing the covariance matrix.Finally,the angle and frequency of the signal source are estimated through a series of linear transformations.The improved propagation operator method not only estimates the angle and frequency information of the signal efficiently and quickly,it also reduces the computational complexity of the algorithm,lower the RMSE and improves the POR.