Abstract:

The traditional algorithms usually discard the difference coarray of the coprime array (CPA) to form the discrete virtual array element and only use the continuous virtual array element to estimate the direction of departure (DOD) and direction of arrival (DOA), which has the problems of limited freedom improvement, poor estimation performance, etc. A joint DOD and DOA estimation algorithm for a CPA based on interpolation virtual arrays is proposed to solve these problems. Firstly, the two interproton arrays are arranged around the zero point to form a transmitting array and a receiving array of a bistatic multiple input multiple output (MIMO) radar respectively. This array structure changes the traditional virtual array element from the array difference coarray structure to the sum coarray structure, reducing the redundancy of the virtual array. Secondly, on the basis of the virtual array element formed, the virtual array element is inserted into the hole position of the virtual array to make it continuous. For the problem that there is no actual received signals of the interpolated virtual array, the equivalent received signal of the interpolated virtual matrix is recovered by the method of Toeplitz reconstruction of the covariance matrix based on the kernel norm minimization optimization theory, which is beneficial to the joint angle estimation of all virtual matrix elements. Finally, in order to solve the problem of high computational load caused by angle pairing, the reduced dimension multiple signal classification (RD-MUSIC) algorithm is used to automatically pair the angles, thereby reducing the computational complexity of the algorithm. The proposed algorithm effectively improves the target resolution and joint angle estimation performance. The simulation experiments verify the effectiveness of the algorithm.

Key words: coprime array (CPA), interpolation virtual array, sum-difference coarray, joint angle estimation