基于子频带分解的宽带信号干涉法测向算法

研究了宽带信号波达角的精确估计方法,提出了一种适合宽带信号的干涉法测向算法。该算法利用阵元间的延时估计波达角。先对信号作快速傅里叶变换(fast Fourier transform,FFT),选取信号在6 dB带宽内的谱线,每根谱线看作一个单频信号,采用窄带鉴相方法对各单频信号分别鉴相并估计该频率点上的延时,最后对各延时估计值进行加权平均。证明了信号在各频率点上的能量与频率平方的乘积是最佳加权系数。本算法具有计算量小、算法简单等优点。延时估计的仿真性能接近克拉美-罗限。

Wideband signal intefferometry direction-finding based on sub-bands decomposition

A method of wideband signal’s direction of arrival(DOA) estimation is addressed,and an algorithm of direction-finding applicable for wideband signals is presented.The time-delay between two elements is estimated and the DOA is obtained afterwards.Firstly,the wideband signal is decomposed into multiple single-tone signals through fast Fourier transform(FFT).The spectrums of FFT within 6 dB bandwidth are used to estimate the phase delay respectively,and then the time-delays are attained.Finally,the accurate time-delay estimate is given by weighting these estimates.The optimum weighting coefficients are given.The algorithm has low computation load.The computer simulation results of time-delay estimate show that the performance is approximately to the Cramér-Rao lower bound.