多径传播条件下宽带线性调频信号波达方向估计方法

Direction-of-arrival Estimation of Wideband Chirp Signals in the Presence of Multipath Propagation

针对信号出现多径传播情况时现有宽带信号波达方向(direction of arrival,DOA)估计方法性能下降的问题,提出了一种多径传播条件下宽带线性调频(chirp)信号波达方向估计方法,该方法将导向有效投影(steered effective projection,STEP)技术与宽带线性调频信号的时频特性相结合,对具有不同时频特性的信号分量进行分离,逐个处理,并以时频分布矩阵代替传统的协方差矩阵,从而构造有效噪声子空间,实现时域角度估计。本方法无需进行信号聚焦操作,因此理论上不受聚焦误差的影响。仿真结果验证了所提方法的有效性。

In order to solve the problem of the performance degradation of existing wideband signal direction of arrival(DOA)estimation method in the presence of multipath propagation,a new DOA estimation method for multipath wideband chirp signals is proposed in this paper.This method is based on the steered effective projection(STEP)technique incorporating the time-frequency structure of wideband chirp signals.A spatial time-frequency distributions matrix rather than the traditional covariance matrix is used to construct the steered effective noise subspace with signal selectivity,based on which the multipath chirp signals can be distinguished and be tackled one by one.It is a time-domain scheme and requires no preliminary DOA estimates for data focusing,thus it is theoretically unaffected by focusing error.Moreover,both the time and frequency information of wideband chirp signals are used through the time-frequency distributions,which improves the estimation accuracy.The performance of the proposed method has been evaluated by extensive simulations,and compared with some current wideband DOA estimation methods.