基于快速富氏变换插值的宽带信号方位估计

提出一种宽带方位估计算法,它利用FFT插值,将实际线列阵接收到宽带信号中的各子带信号转换成相应的虚拟阵列的输出,从而使得各子带张成的信号子空间相同,信号方位估计便可从虚拟阵列的输出中获得。通常宽带方位估计算法需要对方位角进行预估,以便构成聚焦矩阵,而对方位预估的偏差将导致最终方位估计的偏差。本文方法是先对阵列的采样输出进行预处理,再用常规方法来形成统一的采样协方差阵进行方位估计,因此避免了方位预估,使得估计结果是无偏的。仿真结果证明了该方法的有效性。

DOA estimation for wide-band signal using FFT interpolation technique

A method for wide-band DOA estimation is proposed in this paper. By using FFT interpolation technique, virtual arrays outputs of each frequency bin of wide-band signal can be obtained from real array outputs, and these virtual arrays have the same array manifold, so DOA's can be estimated from the outputs of virtual arrays. Ordinarily, preliminary source locations, which are used to construct focusing matrices, should be estimated prior to forming covari-ance matrices, whereas, the method which needs information of source locations suffers from an asymptotic bias, and the bias increases with the deviation of preliminary source location from the true DOA's. The method proposed in this paper, by preprocessing the array outputs, the common covariance matrices can be formed, and DOA's can be estimated by using conventional method.Resultsof DOA estimation are unbiased because this method needn't prior information of source locations. Simulation results are provided to illustrate: the effectiveness of proposed method.