基于对称天线相位干涉仪的入射角估计及跟踪

Estimating and Tracking Angle of Arrival via Phase Interferometer with Symmetric Array

针对现有相位干涉仪角度估计算法在近场条件下性能不佳的问题,该文提出一种远近场均性能良好的改进的导向矢量匹配算法。该算法采用对称结构天线接收来波信号,利用近场条件下对称位置天线的到达相位差中距离相关项对消的特性设计新的代价函数。代价函数最大值位置对应的入射角即为目标信号的入射角估计。在此基础上,利用相关函数的梯度正比于角度误差的特性设计角跟踪环路。作为一种局部极值估计算法,角跟踪环路相比其它全局最大值估计算法具有更好的相位噪声鲁棒性。仿真实验验证了该算法在不同相位噪声以及远近场条件下的优良性能。

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.