The work in this paper is supported by National Natural Science Foundation
of China under Grant No. 61172155 and the Hi-Tech Research and Development
Program of China under Grant Project No. 2013AA122903.
978-1-4799-4195-7/14/$31.00©2014IEEE
Sparse Passive Radar Imaging Based on DVB-S
using the Laplace-SLIM Algorithm
Xiaofei Yu, Tianyun Wang*, Xinfei Lu, Chang Chen, Weidong Chen
Key Laboratory of Electromagnetic Space Information, Chinese Academy of Sciences
University of Science and Technology of China, Hefei, Anhui, P.R. China
*China Satellite Maritime Tracking and Control Department, Jiangyin, 214431, China
Email: {yuxfagn, wangty, lxfei}@mail.ustc.edu.cn, {chench, wdchen}@ustc.edu.cn
Abstract—This paper studies sparse image reconstruction
based on digital video broadcasting-satellites (DVB-S) system. The
signal model is slightly different from our previous research [1-2],
i.e. we consider the Swerling I model to characterize the target
response, which means the scattering coefficients of the target
resonate at different frequencies. Due to this effect, the
performance of the conventional sparse recovery methods would
decrease considerably. By utilizing the sparse learning via iterative
minimization (SLIM) with the Laplace priors, we propose an
effective algorithm named Laplace-SLIM to deal with the
aforementioned joint sparse recovery problem, which can be seen
as a kind of reweighted l
1
-norm algorithm. Simulation results
verify the effectiveness of the proposed method and related
analysis.
Keywords—Sparse passive radar imaging, DVB-S, Swerling I
model, Laplace-SLIM.
I. INTRODUCTION
Passive radar, which is a subset of bistatic radar, uses non-
cooperative illuminator of opportunity as a transmitter. Because
of containing no transmitter, passive radar is virtually
undetectable and there is also no constraint in spectrum
allocation. In the past few years, passive radar systems based on
digital video broadcasting-satellites (DVB-S), FM and GNSS,
etc.[1][2][3] have developed in target detection, tracking and
imaging with numerous advantages, such as low cost, good
accuracy, strong survivability and robustness against deliberate
directional interference.
Compared with terrestrial illuminators, the DVB-S spread
more widely in space and have broader beam coverage. What’s
more, those satellites are geostationary, therefore, there is no
Doppler clutter caused by relative motion. This paper continues
our previous research on imaging for passive radar system based
on DVB-S [1] [2]. As shown in our previous work, we choose 7
available Ku-band DVB satellites which can cover the area of
China. Because there are not enough transmitters due to the
practical limitation, the wavenumber domain coverage is usually
sparse, which directly leads to poor inversion performance using
traditional imaging methods like matched filter (MF) [1].
Nevertheless, considering the fact that most space-borne targets
have limited number of strong scatterers, thus we utilize the
sparse recovery techniques to obtain better imaging performance
from the poor wavenumber coverage.
As shown in our previous work, we assume the scattering
coefficients of the target are the same under the different
frequencies, which is not appropriate according to the radar
target characteristics. In this paper, we generalize our signal
model in [1][2], and consider the Swerling I model to
characterize the target response, which means the scattering
coefficients of the target resonate at different frequencies [4].
Because of neglecting this change, conventional sparse imaging
methods such as BP, OMP etc., cannot reconstruct the target
correctly when snapshots are limit, i.e., would decrease in
performance.
Under the aforementioned assumption of the scattering
coefficients, firstly, we reestablish the receiving signal model
termed as a joint sparse recovery problem, which can be
considered as a generalized multiple measurement vectors
(MMV) case. Then, inspired by the wideband SLIM algorithm
proposed in [5], we introduce an effective algorithm called
Laplace-SLIM to deal with sparse image reconstruction problem
in passive radar system, which is based on the technique of
sparse learning via iterative minimization (SLIM) [6] combined
with the Laplace priors [7]. Our algorithm is based on three
different hierarchical Bayesian statistical models, which gives a
more accurate description of signals and noise similar as the
Bayesian compressive sensing (BCS) denoted in [8]. What’s
more, as shown in the following part of this paper, our algorithm
can been seen as a kind of reweighted l
1
-norm algorithm, which
may have many advantages over wideband SLIM algorithm
proposed in [6], which using reweighted l
2
-norm. In [9], the
authors have presented that the number of iterations of the
reweighted l
1
-norm required is generally much less than the
reweighted l
2
-norm. A second advantage of the reweighted l
1
-
norm algorithm is that it is often much easier to incorporate
additional constraints, e.g., bounded activation or non-negativity
of unknown [10], which exhibits the superior of our method
compared with the existing sparse recovery approaches.
The paper is organized as follows. Section II describes the
modified signal model, including the new DVB-S receiving
echo equation and the novel Bayesian model establishment.
Section III provides a full description of the proposed Laplace-
SLIM Algorithm. In Section IV, we will offer numerical
simulations to demonstrate the performance improvement of our
algorithm compared with several popular sparse imaging
algorithms. Section V draws the conclusions.