Underdetermined DOA Estimation Based On Target Space Diversity

The working environment of modern radars is complex,with many surrounding background targets and electromagnetic interference.Therefore,underdetermined scenario and signal coherence are the two major problems faced by the array radar system in DOA estimation.However,most of the existing algorithms to solve these two types of problems are based on linear arrays and are not suitable for uniform circular arrays(UCA).Compared with the linear array,the UCA has better angle estimation performance and can estimate the pitch angle and the horizontal angle at the same time.Therefore,based on the LFMCW radar,this paper proposes an underdetermined DOA estimation algorithm which is suitable for various array structures.And then the two-dimensional decoherence problem of UCA is studied.The main contents of this paper are as follows:1.An underdetermined DOA estimation algorithm based on target space partitioning is proposed.First,the basic principle of the algorithm is described,and then several feasible partition methods for target space are given,and the time complexity of the algorithm is discussed.The simulation results show that the algorithm can estimate the distance-velocityangle of the target simultaneously,and can improve the accuracy of DOA estimation.2.The DOA estimation algorithm based on target space diversity requires multiple twodimensional peak searches.Aiming at the problem of large computational load and long search time in conventional search algorithms,this paper uses genetic algorithm to search for the two-dimensional spectral peak to reduce the time complexity.The principle of the algorithm is described in detail,and the simulation results are given.3.For the two-dimensional decoherence problem of UCA,a circular array decoherence algorithm based on the combination of CS and GA is proposed.First,the CS method is used for DOA estimation to obtain a rough estimate of the target orientation,and then the GA is used for further spectral peak search to improve accuracy.MATLAB simulation results show that this method has high reliability and feasibility.