单基地互质MIMO阵列DOA估计

Monostatic co-prime MIMO array DOA estimation

针对传统均匀直线阵列的相干目标波达方向估计算法的自由度受限于实际阵列阵元数目的问题,提出基于MUSIC算法的单基地发射/接收和协阵列DOA估计方法。该方法将互质MIMO阵列虚拟成等效的和协阵列,找到和协阵列中的连续子阵和半连续子阵,并运用多频操作填补半连续子阵中的孔洞,使之与连续子阵形成一个更长的新连续子阵;然后通过矩阵重构算法解相干,该方法极大地提高了算法的自由度,可以根据目标的个数灵活调整虚拟发射/接收阵元的数量,使复杂度尽可能降低。但该方法涉及到高维矩阵的特征值分解,复杂度仍然很高,因此文中引入传播算子,提出基于传播算子的单基地发射/接收和协阵列DOA估计方法,避免了特征值分解,复杂度得到极大改善。仿真结果证明,该方法对非相干目标的估计能力与前者接近,可用于估计非相干目标以及估计相干目标的大致方向或者判断此时是否有相干目标出现。

For the degree of freedom of the traditional monostatic uniform linear array based DOA(direction of arrival)estimation of coherent targets is limited to the number of actual array elements,a monostatic transmit/receive(T/R)sum coarray DOA estimation method based on MUSIC(multiple signal classification)algorithm is proposed.In this method,the coprime MIMO(multiple-input multiple-output)array is virtualized into an equivalent sum co-array,the continuous and semicontinuous sub-arrays in the co-array are found out,and multi-frequency operation is used to fill the holes in the semi-continuous sub-array to form a new longer continuous sub-array together with the continuous sub-array,and then the decoherence is carried out with the matrix reconstruction algorithm.This method greatly improves the degree of freedom of the algorithm and can flexibly adjust the number of virtual T/R array element according to the number of targets,which makes the complexity as low as possible.However,the eigenvalue decomposition of high-dimensional matrices is involved in this method,so the complexity is still very high.In view of this,a monostatic T/R sum co-array DOA estimation method based on propagator method is proposed,which avoids the eigenvalue decomposition,and the complexity has been greatly reduced.Simulation results show that the estimation ability of this method for incoherent targets is close to that of the former,but its estimation ability for coherent targets is weak.Therefore,it can be used to estimate the direction of incoherent targets and the approximate direction of coherent targets or to judge whether coherent targets appear at this time.