Research On Direction-of-arrival Estimation Algorithm Using MIMO Radar

MIMO radar attracts researcher's attention internationally in recent years. Under the new system, more complete information of target and environment can be obtained in the time-, frequency-, code-, and space-domain. Specially, spatial diversity and signal diversity of MIMO radar, improve target detection, parameter estimation, as well as the essential breakthrough of radar techniques performance possible. With spatial diversity and signal diversity of MIMO radar, new algorithms are proposed aiming at target identifiability and location. The proposed algorithms are proved effective by field data of MIMO radar experimental system.1) Estimation of DO A through signal diversity is studied based on co-located arrays. Firstly, A method of the MIMO array design is proposed based on spatial convolution principle. Based on the principle of improving performance of estimation of DOA by signal diversity, then a Virtual Subarray Smoothing(VSS) algorithm is proposed for the coherent case,which avoids the reduction of the array effective aperture compared with traditional FBSS. Based on MIMO signal diversity techniques, a new 2-D direction-of-arrival estimation algorithm is proposed, and the performance of a rectangle planar array is obtained from an L-shaped array. Theoretical analysis and the simulation results show that the proposed algorithms are effective.2) Estimation of DOA through spatial diversity is studied with the transmit elements widely separated and the receive elements closely spaced. A Virtual Subarray Accumulation(VSA) algorithm is proposed, which achieves angle super-resolution of MIMO radar. And sidelobes of DOA estimation are analysized, which are equal in some conditon. Then a Spectrum Selection(SPS) algorithm is proposed, and the algorithm obtains the best estimations of all targets from every subarrary. Then a Subarray Combination Estimation (SCE) algorithm is proposed, which combinates estimations for all subarrays after signal augment. Furthermore, a Subarray Estimation Selection(SES) algorithm is proposed for MIMO radar DOA estimation, and can be extended in 2-D location of MIMO radar expediently. Based on measured data by author, the proposed algorithms are proved validility.3) With two characters of MIMO radar, based on distributed elements and distributed subarrays, detection and location of MIMO radar are solved by estimation of DOA theories. Aiming at ideal targets,a multi-target resolution of near-field algorithm based on MIMO radar is proposed. Then, an estimation of DOA algorithm based on MIMO configuration is proposed, and the performance of improving degrees of freedom is embed in distributed MIMO radar. Furthermore, a generalizing Pisarenko algorithm is proposed based on multiple subarrays configuration in order to locate targets, and the number of targets can be determined synchronously.4) MIMO radar experimental system is designed. At last, The experiment using real array and equivalent array, show the augment of the array virtual aperture,and the improved resolution of DOA.