DOA Estimation Of Non-equal Power Coherent Signal

As one of the important research contents in array signal processing,the direction of arrival estimation has a wide range of applications in the fields of electronic countermeasures,navigation and mobile communications.In a complex electromagnetic environment,there are not only incoherent signals but also a large number of coherent signals,and the power between the signals is not equal.Aiming at this complex electromagnetic environment,this paper mainly studies the DOA estimation of non-equal power coherent signals,and the DOA estimation of non-equal power coherent and non-coherent mixed signals,and gives an algorithm with good estimation performance.The details are as follows:The influence of signal power on MUSIC algorithm,forward and backward spatial smoothing algorithm,JJM algorithm,invariant noise subspace algorithm,invariant noise subspace smoothing algorithm is studied,and simulation analysis is performed.For non-equal power coherent and non-coherent mixed signals,an invariant noise subspace difference algorithm is studied.This algorithm can separate incoherent and coherent signals from mixed signals.For incoherent signals,the invariant noise subspace algorithm is used for estimation;for coherent signals,the constructed spatial difference matrix is used for estimation.Incoherent signals and coherent signals can be processed in parallel.The algorithm can estimate the number of signals more than the number of elements and shorten the running time.The simulation results show that when the power of different signals is too large and other algorithms fail,the invariant noise subspace difference algorithm can still realize the direction of arrival estimation of the mixed signal.Aiming at the DOA estimation of non-equal power coherent signals,an invariant noise subspace algorithm based on Toeplitz matrix reconstruction is studied.The algorithm first arranges the correlation functions between the received data of each array element and the received data of the reference array element,and constructs Fullrank Toeplitz matrix;then introduce a virtual source to optimize the Toeplitz matrix,and use its invariant noise subspace characteristics to estimate the direction of arrival of the signal.The algorithm makes full use of the data received by the array and its complex conjugate information,increases the number of coherent signals that can be estimated,and improves the performance of DOA estimation for coherent sources.The simulation results show that the algorithm can accurately estimate the DOA of the coherent signal with a strong signal power of 30 d B,a strong signal power difference of40 d B,and an angle of 2 degrees adjacent to each other;under the same simulation conditions,it has a higher success rate and a higher success rate than the spatial smoothing algorithm.Strong resolution.The complexity of the invariant noise subspace algorithm based on Toeplitz matrix reconstruction is analyzed,and a DOA estimation algorithm based on eigenvalue reconstruction and real value transformation is studied.Through the reconstruction of the eigenvalues,the real-value transformation of the reconstructed matrix,the peak search in the half-spectrum region of the spatial spectrum,and the use of specific rules to determine the true direction of arrival.Without reducing the performance of the algorithm as much as possible,the complexity is reduced to one-eighth of the invariant noise subspace algorithm for Toeplitz matrix reconstruction.