Sensors 2013, 13, 11490-11497; doi:10.3390/s130911490
sensors
ISSN 1424-8220
www.mdpi.com/journal/sensors
Article
Covariance-Based Direction-of-Arrival Estimation of Wideband
Coherent Chirp Signals via Sparse Representation
Zhichao Sha *, Zhengmeng Liu, Zhitao Huang and Yiyu Zhou
College of Electronic Science and Engineering, National University of Defense Technology,
Changsha 410073, China; E-Mails: liuzhangmeng@nudt.edu.cn (Z.L.);
taldcn@gmail.com (Z.H.); zhouyiyu@sohu.com (Y.Z.)
* Author to whom correspondence should be addressed; E-Mail: shazhichao_163@163.com;
Tel.: +86-1317-0302-060; Fax: +86-731-8457-3489.
Received: 23 May 2013; in revised form: 8 August 2013 / Accepted: 19 August 2013 /
Published: 29 August 2013
Abstract: This paper addresses the problem of direction-of-arrival (DOA) estimation of
multiple wideband coherent chirp signals, and a new method is proposed. The new method
is based on signal component analysis of the array output covariance, instead of the
complicated time-frequency analysis used in previous literatures, and thus is more compact
and effectively avoids possible signal energy loss during the hyper-processes. Moreover,
the a priori information of signal number is no longer a necessity for DOA estimation in
the new method. Simulation results demonstrate the performance superiority of the new
method over previous ones.
Keywords: direction-of-arrival (DOA) estimation; wideband chirp signal; sparse
representation; convex optimization
1. Introduction
Previous direction-of-arrival (DOA) estimation methods for wideband chirp signals are mostly
based on the special time-frequency distribution of such signals. Ma and Goh separate the
simultaneous chirp signals first according to their distinguishable auto- or cross-terms in the ambiguity
function, and then use the secondary time-frequency data to estimate their directions [1]. Their
methods are grounded on the assumption that the signals are separable in the time-frequency domain,
so they are not usable for completely overlapped coherent chirp signals. Wang and Xia use the chirp