Cooperative track initiation for distributed
radar network based on target track
information
ISSN 1751-8784
Received on 23rd January 2015
Revised on 30th September 2015
Accepted on 12th October 2015
doi: 10.1049/iet-rsn.2015.0312
www.ietdl.org
Hongwei Liu, Hongliang Liu, Xiaodong Dan, Shenghua Zhou
✉
, Jun Liu
National Laboratory of Radar Signal Processing, Xidian University, Xi’an 710071, Shannxi, People’s Republic of China
✉ E-mail: shzhou@mail.xidian.edu.cn
Abstract: Distributed radar network can significantly improve target localisation accuracy on condition that targets can be
successfully tracked by all radar sites. However, since different radar sites often have different signal-to-noise ratios with
respect to even the same target, it is difficult for all radar sites to track a target simultaneously. In this case, the authors
propose a cooperative track initiation algorithm for distributed radar network. It aims to improve track initiation
performance of invisible radar sites that have not initiated the target track, by using target track information provided
by the radar sites that have tracke d the target. Based on the target track information, the invisible radar sites would
predict a region where the target will be present, and decrease detection thresholds in the predicted region according
to a given probability of false track initiation. Numerical results indicate that the proposed algorithm ca n significan tly
improve the probability of target track initiation.
1 Introduction
Distributed radar network [1–3] is a hot topic in the radar field since
it owns many advantages over a single radar, such as improved
detection, tracking and localisation performance [4, 5]. It is known
that a higher localisation accuracy relies on the precondition that
all the relevant radar sites have successfully tracked the target. In
real applications, since different radar sites often have different
signal-to-noise ratios (SNRs), they often do not initiate the target
track simultaneously. Hence an interesting problem is, how to
improve track initiation performance of the invisible radar sites
with the aid of the radar sites that have tracked the target.
For traditional monostatic radar systems, track initiation is
generally performed without any assistant information, and there
are mainly two strategies [6]: the sequential processing strategy
and the batch processing strategy. For the former, such as the
rule-based method and the logic-based method [7], the received
data of each scan (frame) are processed one by one until a target
track is established. The sequential processing strategy needs a low
computation cost, but requires some rough information (maximum
velocity) about target motion. For the latter, such as the Hough
transform method [8] and the modified Hough transform method
[9, 10], the received data of some scans are processed together to
establish a target track. The batch processing strategy works well
in the environment of dense clutter, but suffers from a heavy
computation burden. All these track initiation strategies are
referred to as non-cooperative mode, since they are designed
without a prior knowledge of target motion status. In distributed
radar network, however, one radar site can receive target track
information from other radar sites that have tracked the target. The
motivation of this work is, how to use the fed-in target track
information to improve detection performance and then track
initiation performance of the invisible radar sites.
There are lots of works concerning how to use target track
information for target detection. A typical joint detection and
tracking scheme is the track-before-detection (TBD) strategy [11],
which can improve SNR through accumulation along successive
scans, but the high computation cost hinders its real application.
Another scheme is to adjust detection thresholds in target’s
predicted region. A line of research [12–15] concentrates on
optimising spatially identical detection thresholds in the predicted
region to maximise tracking performance. The essential of the
threshold optimisation strategy is to decrease detection thresholds
for a higher detection probability and hence improve tracking
performance. Once applied to target track initiation, they do not
have a mechanism to control the probability of false track
initiation, and may trigger many false tracks messing up with real
targets. Distinct from this strategy, in [16], spatially varying
detection thresholds in the predicted region are presented under the
Bayesian criterion [17], called a Bayesian detector. The Bayesian
detector works well for non-manoeuvring targets, but for
manoeuvring targets, the real target location may deviate from the
predicted centre, which may degrade detection performance.
Moreover, the spatially varying detection thresholds are given for
all continuous locations in the predicted region, but in radar
applications, one resolution cell requires one detection threshold,
rather than the location-continuous detection thresholds. Besides,
the detection thresholds of the Bayesian detector are dependent on
a so-called tunable parameter, but no strategy is given to set the
tunable parameter. Hence the Bayesian detector cannot control the
probability of false track initiation, either.
To improve track initiation performance at an acceptable false
track level, in [18], we study how to set detection thresholds in the
predicted region under a constant probability of false track
initiation, and mainly discussed spatially identical detection
thresholds (a uniform method) for non-manoeuvring targets. In
this paper, we expand the previous work to manoeuvring
situations, and consider spatially varying detection thresholds (a
non-uniform method) in the predicted region. Explicitly, given a
probability of false track initiation, we first calculate a so-called
frame false alarm rate, that is, the probability that there exists at
least one false alarm in the predicted region. Under the frame false
alarm rate, detection thresholds of resolution cells in the predicted
region are calculated according to the probability of target being
present in each resolution cell. Furthermore, we evaluate track
initiation performance of the uniform method and non-uniform
method, for both non-manoeuvring targets and manoeuvring
targets. Numerical results indicate that both methods can improve
the track initiation performance compared with traditional track
initiation algorithm. Moreover, the uniform method has a better
performance for manoeuvring targets, while the non-uniform
method performs better for non-manoeuvring targets.
The rest of the paper is organised as follows. Section 2 introduces
the mathematical model for cooperative track initiation problem. In
IET Radar, Sonar & Navigation
Research Article
IET Radar Sonar Navig., 2016, Vol. 10, Iss. 4, pp. 735–741
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The Institution of Engineering and Technology 2016