Research Article
The Application of JDL to Suppress Sea Clutter for
Shipborne HFSWR
Zhenyuan Ji, Chunlei Yi, Junhao Xie, and Yang Li
Department of Electronic Engineering, Harbin Institute of Technology, Harbin 150001, China
Correspondence should be addressed to Junhao Xie; xj@hit.edu.cn
Received April ; Revised October ; Accepted October
Academic Editor: Michelangelo Villano
Copyright © Zhenyuan Ji et al. is is an open access article distributed under the Creative Commons Attribution License, which
permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
is paper deals with the problem of sea clutter suppression for shipborne high frequency surface wave radar (HFSWR) based on
the joint domain localized (JDL) adaptive processing algorithm. e performance of the novel method is compared with D FFT
plus digital beamforming (FFT-DBF) and orthogonal weight in dierent azimuths. e results based on simulated and real data
show that the novel method provides higher detection performance than others.
1. Introduction
HFSWR can be classied into onshore HFSWR and ship-
borne HFSWR according to the platform where HFSWR is
located. ere are many literatures about target detection and
trackingbasedononshoreHFSWR[, ]. When HFSWR
is mounted on a moving shipborne platform, the rst-order
Bragg lines are spread in Doppler domain []. Besides, the
sea clutter spectrum is spatially temporally coupled with
each other. e background for the detection of high-velocity
targets such as aircras and missiles is still the high-order
sea clutter and noise because of their large Doppler shi.
ese targets can be handled just like onshore HFSWR.
However, for the targets located among the spread rst-order
sea clutter spectrum, they are more dicult to be detected.
e sea clutter suppression of space-time adaptive processing
(STAP) may be better than that of the cascaded space-time
processing.
STAP was proposed by Brennan and Reed in s [],
which was rst used in the airborne radar, to suppress ground
clutter. To reduce the computational complexity of STAP,
reduced-dimension STAP is used generally. For the homo-
geneous clutter, reduced-dimension STAP methods mainly
contain JDL [, ], space-time multiple-beam (STMB) algo-
rithm [], linear equations [], and the two-data-set (TDS)
algorithm []. For the nonhomogeneous clutter, there are the
direct data domain (D) [], AR model [], and so on.
Among the shipborne radar clutters, sea clutter is con-
sidered to be more complex. However, the research of the
sea clutter suppression for shipborne HFSWR is very limited.
e orthogonal weight algorithm proposed in []iseective,
but it is one-dimensional processing. e simulation of
STAPtechniquehasbeengivenbasedonaconventional
architecture of processing []. However, the computational
complexity of the conventional STAP is rather large.
Consider a line array antenna with spatial chan-
nels and pulses per coherent processing interval (CPI).
Conventional STAP algorithm uses all degrees of
freedom (DOF). In practice, 2 independent, identically
distributed (i.i.d.) secondary data samples are needed to
approach the optimal performance (−dBloss)[]. Because
of the estimation error between real sea clutter covariance
matrix in interested range cell and the estimated one using
the samples around interested range bin, this method exists
the signal-to-noise ratio loss depending on the number of
secondary data samples to some extent. Obtaining such
a large number of i.i.d. samples is dicult especially for
shipborne HFSWR. Generally, if is and is , that
needs at least range data samples to estimate clutter
covariance. Furthermore, even if i.i.d. samples are available,
the associated computation expense makes this fully adaptive
algorithm impractical. en, a reduced-dimension STAP
algorithm JDL is rst used to suppress sea clutter of shipborne
HFSWR in this paper. Adaptive processing is restricted to
Hindawi Publishing Corporation
International Journal of Antennas and Propagation
Article ID 825350