Published in IET Radar, Sonar & Navigation
Received on 5th March 2014
Revised on 24th July 2014
Accepted on 29th July 2014
doi: 10.1049/iet-rsn.2014.0300
ISSN 1751-8784
Space-time adaptive processing-based algorithm for
meteor trail suppression in high-frequency surface
wave radar
Zhang Xin
1
, Su Yanhua
2
, Yang Qiang
1
, Dong Yingning
1
, Deng Weibo
1
1
School of Electronics Information Engineering, Harbin Institute of Technology, Room 807 in New Technology Building,
92# West Dazhi Street, Harbin, Hei Longjiang, People’s Republic of China
2
The Fourth Department of Headquarters of Navy, Beijing 100841, People’s Republic of China
E-mail: dengweibo@hit.edu.cn
Abstract: Meteor trail arises as a result of meteorites burning in the Earth’s atmosphere at far altitudes with the characteristics of
short lifetime and the ability of scattering high-frequency (HF) signal. It is a classical universal interference for high-frequency
surface wave radar, which can provide the capabilities of target monitoring and ocean remote sensing by working on HF band. In
this study, the authors propose the superiorities of utilising the space-time adaptive processing-based algorithm for meteor trail
suppression. They modify the calculation of the covariance matrix based on the distribution and characteristics of meteor trail
aiming to fit for meteor trail better. Finally, they verify the effectiveness of the modified algorithm by measured data. The
results show that the modified algorithm can not only detect targets better, but can also make Bragg lines buried in meteor
trail visible.
1 Introduction
High-frequency surface wave radar (HFSWR) can provide the
capabilities of targets monitoring and ocean remote sensing
over the horizon (OTH) by transmitting high-frequency
(HF) vertical polarisation electromagnetic wave. It works on
HF of 3–30 MHz. However, the HF band is very congested
and has very complicated electromagnetism environment,
which often contains not only strong clutter (such as sea
clutter and ionospheric clutter) and strong directional
interferences (such as radio interference), but also th e
interferences from universe and atmosphere [1].
Sea clutter is the echo from a water surface, and its
amplitudes spread from cell to cell, typically described by a
Weibull or log-normal distribution [2]. For target detection,
sea clutter is ‘clutter’ to be suppressed, however, for ocean
remote sensing, it is used to obtain the information of the
ocean.
Ionospheric clutter is the echo from single or multiple
ionospheric layers characterised by the strong dependence
of propagation effects on radar frequency [2]. Sky-wave
OTH radar can realise detection ranges in the order of
thousands of kilometres by taking advantage of ionosphere.
However, for HFSWR, the echo from ionosphere will make
the radar blind at the far ranges. Many researchers pay their
attention to how to suppress the ionospheric clutter in
HFSWR.
Radio, which works on HF band, can be received by
HFSWR receiver. For HFSWR, it is a kind of strong
directional interference with a stable direction. For this kind
of interference, we can use adaptive beam forming to
suppress it.
Meteor trail is an important interference from the universe
and has an adverse effect on remote targets monitoring and
Bragg lines extraction. However, it has not drawn as much
attention as the ionospheric clutter. There is little literature
about how to suppress the meteor trail, especially for
HFSWR system.
In this paper, we focused on the meteor trail in HFSWR.
Firstly, we analyse the distribution and the characteristics of
meteor trail in HFSWR based on measured data in Section
2. According to the analysis in Section 2, we proposed to
utilise the space-time adaptive processing (STAP) algorit hm
for suppressing the meteor trail. In Section 3, we introduced
the background of STAP. The key contribution of this
paper was a modified adaptive algorithm specifically
designed for the meteor trail shown in Section 4. At the end
of this paper, the superiority of our proposed algorithm was
demonstrated via simulation based on measured data.
2 Distribution and characteristics of meteor
trail
In HFSWR system, long coherent integration time (CIT) is
necessary for better detection performance and higher
Doppler resolution. The CIT is often tens to hundreds of
seconds in HFSWR. Some interferences, named transient
interferences, can only last for a very short time but the
energy can be very strong. Owing to the characteristics of
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IET Radar Sonar Navig., 2015, Vol. 9, Iss. 4, pp. 429–436
doi: 10.1049/iet-rsn.2014.0300
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