锥面共形阵列非圆信号2D-DOA估计

2D-DOA estimation on conical conformal array antennas for non-circular signals

针对常用锥面载体的单曲率特性,结合合理的阵元布局和利用非圆信号非零椭圆协方差特性,提出一种锥面共形阵列天线非圆信号盲极化二维波达方向(two dimensional-direction of arrival,2D-DOA)估计方法。该方法基于非圆-旋转不变子空间(non-circular estimation of signal parameters via rotation invariant technique,NC-ESPRIT),充分利用非圆信号的阵列扩展性,将DOA与极化参数去耦合,在此基础上,对俯仰与方位角度参数分维处理,在未知极化参数的情况下,实现了2D的分维估计。针对相干源情况,推导了锥面共形阵列非圆信号解相干空间平滑算法,通过解相干预处理,保证了所提算法对相干信号的适用性,扩展了算法的应用范围。计算机仿真实验表明,所提方法在信噪比较低(小于10dB)时,较之已有算法大大提升了DOA估计精度,达到了较好的效果。

In view of the single curvature surface of the conical carrier,combining with rationally-placed sensor elements and non-circular signal’s character that its oval covariance matrix is not equal to zero,the method of blind two dimensional-direction of arrival(2D-DOA)estimation on non-circular signals with conical conformal array antennas with respect to polarization diversity is proposed.The parameters of polarization diversity and DOA are decoupled by the method which is based on the idea of non-circular estimation of signal parameters via rotation invariant technique(NC-ESPRIT),thoroughly taking advantage of array augmentation of non-circular signals.On this basis,2D-DOA is realized without knowing the polarization diversity of antennas by separable dimension processing of azimuth and pitch angles.In view of coherent signals,conical conformal array for noncircular signal de-correlation spatial smoothing algorithm is deduced.Applicability for coherent signals is ensured and the application range of the algorithm is extended by preprocessing of de-correlation.The computer simulation demonstrates that the proposed algorithm promotes the accuracy of DOA estimation greatly compared to the existed algorithm at low signal-to-noise ratio(lower than 10 dB)and has better effectiveness.