Research On Direction Of Arrival Estimation Algorithm For Coprime MIMO Radar

The coprime array MIMO radar uses the coprime array as the transceiver array of the MIMO radar,which can fully combine the greatly expanded array aperture of the coprime array and the advantages of the MIMO radar can virtualize the virtual array far exceeding the number of real array elements.In scenarios where software and hardware conditions are limited,it achieves excellent estimation or detection performance,so it has great theoretical research value and practical application value.Based on the coprime array MIMO radar,a series of in-depth studies and improvements are carried out in this paper.The specific work is as follows:1.The related contents of spatial spectrum estimation,coprime array spatial spectrum estimation theory,and MIMO radar are described,including research background,domestic and foreign research status,etc.The geometric topological structures of several classic arrays are analyzed,and the spatial spectrum estimation system model under each array is established based on the array structure;The theoretical basis of several classic spatial spectrum estimation algorithms is described,and preliminary MATLAB simulation experiments are performed to illustrate the estimation performance of each algorithm and array.2.A monostatic unfolded coprime array MIMO radar based on multiple signal classification(MUSIC)estimation of the direction of arrival(DOA)estimation algorithm,namely the UCM-MUSIC algorithm,is proposed.Firstly,the two subarrays of the coprime array are fully expanded to form the unfolded coprime array,and then the unfolded coprime array is applied as the transceiver array of the MIMO radar,respectively.Benefit from the virtual array formed by the unfolded coprime array MIMO radar and the greatly expanded array aperture,The algorithm achieves significantly improved degrees of freedom,excellent resolution at low signal-to-noise ratio,and excellent resolution at small angle-spaced sources.Subsequently,for the eigenvalue decomposition of the algorithm involving high-dimensional matrices,a monostatic unfolded coprime array MIMO radar DOA estimation method based on the propagator method(PM)algorithm was further proposed,namely the UCM-PM algorithm.The algorithm uses the idea of matrix partitioning instead of eigenvalue decomposition to obtain noise subspace,which makes the complexity of the algorithm lower than that of the UCM-MUSIC algorithm.When the signal to noise ratio is greater than 2d B,the approximate performance of the UCM-MUSIC algorithm can be achieved;detailed performance analysis,theoretical proof without phase-ambiguity,and simulation verification are given.3.A joint dimension-reduced DOD and DOA estimation algorithm for bistatic unfolded coprime array MIMO radar is proposed.Based on the array structure of bistatic unfolded coprime array MIMO radar and the idea of dimension-reduced,the algorithm converts the exhaustive search of two-dimensional spectrum peaks in the twodimensional MUSIC algorithm into solving constrained quadratic optimization problems by adding constraints and constructing a cost function,the DOA and DOD is get successively and paired automatically.At the same time,due to the introduction of the dimension-reduced idea,the algorithm does not need two-dimensional exhaustive search,so the complexity is greatly reduced compared to the two-dimensional MUSIC algorithm.Benefit from the virtual array formed by the unfolded coprime array MIMO radar and the greatly expanded array aperture,the proposed algorithm achieves significantly improved resolution,degrees of freedom,and better estimation performance at low signal to noise ratios;detailed complexity analysis,theoretical proof without phase-ambiguity,and simulation verification are given.