Estimating and tracking Angle Of Arrival via phase interferometer with symmetric array

The exiting algorithms for Angle Of Arrival (AOA) estimation of incident signal via phase interferometer may degrade significantly for near-field target. To deal with this issue, a Modified Steering Vector Matching (MSVM) algorithm with the good performance in both far field and near field is proposed. Symmetric array is employed to receive signal. The phase difference of antennas in symmetric position is independent on range as the terms related to range in arriving phases are cancelled. Accordingly, a cost function, which is only related to the AOA in near field, is derived, and the AOA of incident signal can be estimated by finding the maximal value of the cost function. Based on MSVM algorithm, an angle tracking loop is proposed by employing the feature that the gradient of cost function is proportional to the angle error. As a fast algorithm for finding local extremum of cost function, angle tracking loop is obviously more robust than other algorithm searching global maximum in terms of phase noise. Simulations are implemented to verify the excellent performance of angle tracking loop under different phase noise and range scenarios.