Adaptive Sparse Recovery of Moving Targets
for Distributed MIMO Radar
Hui Yu
1, a
, Guanghua Lu
1,b
,
Hailong Zhang
1,c
1
University of Science and Technology of China, Hefei, Anhui, P.R.China
a
yuhuimia@mail.ustc.edu.cn,
b
lugh@ustc.edu.cn,
c
hailong@mail.ustc.edu.cn
Keywords: Adaptive sparse representation, distributed multiple-input multiple-output(MIMO) radar,
moving target imaging, FOCal Underdetermined System Solver(FOCUSS).
Abstract. The high resolution and better recovery performance with distributed MIMO radar would
be significantly degraded when the target moves at an unknown velocity. In this paper, we propose
an adaptive sparse recovery algorithm for moving target imaging to estimate the velocity and image
jointly with high computation efficiency. Numerical simulations are carried out to demonstrate that
the proposed algorithm can retrieve high-resolution image and accurate velocity simultaneously even
in low SNR.
Introduction
The distributed multi-input multi-output(MIMO) radar system has attracted a lot of attentions due to
its high resolution for imaging[1]. It employs widely separated antennas within the transmit and
receive aperture to exploit the spatial diversity. One of its applications is imaging of moving targets.
It is necessary to estimate the velocity of moving targets. The reconstructed targets will be blurred
when we ignores the velocity information[2] as the observation matrix will be affected by the
velocity[3]. In [4], an over complete dictionary(OCD) method is used. It linearizes the forward model
with every possible velocity and solves the moving target problem as a larger, unified regularized
inversion problem. Obviously, it leads to a huge computational burden. In[5], an iterative algorithm
named adaptive subspace pursuit(ASP) is proposed. It linearizes the dictionary matrix at local
neighborhood of the velocity with Taylor expansion, then obtains the new velocity by alternatively
estimating. However, the performance of ASP relies on a priori knowledge of the target’s sparse
degree and the initial velocity which is difficult to know in priori for non-cooperative targets. Without
the priori knowledge of target, ASP fails.
High resolution is another aspect we must care about. Compressive sensing(CS) has shown good
performance in radar imaging recently for its promotion of resolution[6]. Under the assumption that
the scatters of the targets are sparsely distributed, which is the usual case, it can provide higher
resolution than the traditional IDFT method. FOCal Underdetermined System Solver(FOCUSS)[7]
is an implementation of CS. It is shown that FOCUSS can not only recover static image accurately
without a priori knowledge of the targets but also has a good performance even in noisy environments.
In this paper, an adaptive sparse recovery via velocity estimation(ASRVE) method based on
FOCUSS is devised. With an iteration mechanism, the proposed method updates the image and
estimates the velocity alternately by sequentially minimizing the norm and the recovery error.
ASRVE can recover the image and estimate the velocity accurately without a priori knowledge of
target while it is with high computation efficiency.
The next of the paper is as follows. In section 2, the signal model is given and the imaging problem
is formulated. In Section 3, the proposed adaptive sparse recovery algorithm is presented. In Section
4, some experimental results are given to verify the algorithm. Finally, some conclusions are drawn
in Section 5.
Signal Model for a Distributed MIMO Radar System
Consider a distributed MIMO radar system with M transmitters and N receivers[8] which are located