1,721,241 research outputs found
Data fusion performance of HFSWR-systems for ship traffic monitoring
No full textIn Maritime Situational Awareness (MSA), low-power High-Frequency Surface-Wave (HFSW) radars fit the role of long-range early-warning tools by virtue of their over-the-horizon (OTH) coverage. Unfortunately these sensors, developed mainly for ocean remote sensing applications, exhibit poor range and azimuth resolution, high non-linearity and significant false alarm rate due to clutter and interference. For these reasons, the Joint Probabilistic Data Association (JPDA) logic, followed by the Unscented Kalman Filter (UKF), is proposed. Then, to exploit two simultaneously operating HFSW radars with overlapping fields of view, a track-to-track association and fusion (T2T-A/F) logic is applied. The capabilities of the JPDA-UKF tracking algorithm in combination with the T2T-A/F strategy are evaluated using a set of purpose-defined performance metrics, such as the time-on-target (ToT), the false alarm rate (FAR) and the root mean square error (RMSE). Special attention is paid to the comparison of the JPDA-UKF with the 3D (rangeazimuth-doppler) Ordered Statistics Constant False Alarm Rate (OS-CFAR) detection algorithm. A procedure based on track length modelling for the analysis of true and false tracks is presented as well. Single-sensor and multi-sensor tracking performances are investigated using real data collected during the NATO Battlespace Preparation 2009 (BP09) HF-radar experiment, which took place between May and December 2009 in the Mediterranean Sea. Ship reports from the Automatic Identification System (AIS) are used as ground truth information. Experimental results are reported and discussed
Maritime surveillance with multiple over-the-horizon HFSW radars: An overview of recent experimentation
No full textThis paper briefly explores the high-frequency surface-wave (HFSW) radar technology in general, and Wellen radar (WERA) in more detail. Then it describes the multitarget tracking data fusion (MTTDF) network architecture developed at Science and Technology Organization (STO) Centre for Maritime Research and Experimentation (CMRE) and discusses its capabilities in two real study cases: the first in the Ligurian Sea, Mediterranean [11]-[13], and a second in the German Bight, North Sea [14], [15]. In both cases, the main task of the HFSW radars is to estimate sea surface currents. In the second study case, the data recorded by the single stations are sent directly to the Centre's Data Base (DB) and then processed in real-time. The historical information about ship traffic can be exploited not only for assessing system performance, but also in the field of knowledge-based (KB) tracking, for improving system capabilities. In this sense, simulation results are presented and discussed. Finally, a tool developed at STO CMRE, the so-called maritime situational awareness (MSA) viewer, allows displaying from the operator's point of view the maritime picture of the surveyed area
Multiple oceanographic HF surface-wave radars applied to maritime surveillance
No full textIn the context of maritime surveillance, low-power high-frequency surface-wave (HFSW) radars are attracting significant attention as cost-effective tools for long-range ship detection and tracking applications. In this paper, multi-target tracking and data fusion techniques are applied to live-recorded data from a network of three oceanographic HFSW radars installed on the coast of the German Bight, in the North Sea. This campaign follows a previous one conducted in 2009, in which two HFSW radars were deployed on the coast of the Ligurian Sea, in the Mediterranean. Ship reports from the automatic identification system, recorded from a number of coastal stations, are exploited as ground truth information. A methodology is then applied to classify the fused tracks and to estimate single-sensor and data fusion performances. Both in situ and model data are used to investigate the capabilities of the systems according to the variations of the meteorological and oceanographic conditions. Finally, preliminary results are presented and discussed, together with outlines for future works
Maritime surveillance using multiple high-frequency surface-wave radars
No full textIn the last decades, great interest has been directed toward low-power high-frequency (HF) surface-wave radars as long-range early warning tools in maritime-situational-awareness applications. These sensors, developed for ocean remote sensing, provide an additional source of information for ship detection and tracking, by virtue of their over-the-horizon coverage capability and continuous-time mode of operation. Unfortunately, they exhibit many shortcomings that need to be taken into account, such as poor range and azimuth resolution, high nonlinearity, and significant presence of clutter. In this paper, radar detection, multitarget tracking, and data fusion (DF) techniques are applied to experimental data collected during an HF-radar experiment, which took place between May and December 2009 on the Ligurian coast of the Mediterranean Sea. The system performance is defined in terms of time on target (ToT), false alarm rate (FAR), track fragmentation, and accuracy. A full statistical characterization is provided using one month of data. The effectiveness of the tracking and DF procedures is shown in comparison to the radar detection algorithm. In particular, the detector's FAR is reduced by one order of magnitude. Improvements, using the DF of the two radars, are also reported in terms of ToT as well as accuracy
Detection, tracking and fusion of multiple HFSW radars for ship traffic surveillance: Experimental performance assessment
No full textLow-power HF surface-wave radars fit well the role of long-range early-warning tools in maritime situational awareness applications, by virtue of their over-the-horizon coverage capability and continuous-time mode of operation. In fact, these sensors, developed for ocean remote sensing, can represent also a further low-cost source of information for ship detection and tracking. Unfortunately, many shortcomings, like poor range and azimuth resolution, high non-linearity and significant presence of clutter, may degrade their performance. In this paper, multi-target tracking and data fusion techniques are applied to experimental data collected during the NATO Battlespace Preparation 2009 HF-radar campaign, which took place between May and December 2009 in the Mediterranean Sea. The system performance is defined in terms of time-on-target, false alarm rate and accuracy. Experimental results are presented and discussed
Application of the JPDA-UKF to HFSW radars for maritime situational awareness
No full textAt the present day, growing interest is paid to the development of more reliable surveillance systems for maritime situational awareness (MSA). The purpose is to detect, track and classify cooperative and non-cooperative targets. For this reason, great interest is given to low-power/cost High-Frequency Surface-Wave (HFSW) radars as an early-warning tool for over-the-horizon (OTH) applications. However, in HFSW radars there is a trade-off in terms of quality and cost, i.e. the radar system exhibits poor azimuth resolution, high non-linearity, and significant false alarm rate. All these aspects reduce tracking performance if not properly addressed. In this context, the Joint Probabilistic Data Association (JPDA) with the Unscented Kalman Filter (UKF) is proposed. The tracking algorithm behavior is investigated by a comparison between the tracks generated by two HFSW radars, with overlapped fields of view, and Automatic Identification System (AIS) data. A discussion is provided about the possible effectiveness of HFSW radar fusion strategies. Preliminary results from a HFSW Radar experiment are reported and discussed
The impact of sea state on HF surface-wave radar ship detection and tracking performances
No full textNowadays, we face an ever increasing interest in new technologies and solutions for the maritime surveillance (MS) domain. In such a context, oceanographic high-frequency surface-wave (HFSW) radars have started to get significant attention. In fact, they are operated to provide remote sensing information of wide open-sea areas, but they may also contribute with useful cost-effective track-based information to current operational MS systems. In this paper, specific interest is devoted to the analysis of the system detection and tracking capabilities under different meteo-oceanographic (METOC) conditions. Experimental data are acquired by three HFSW radars operated by the Helmholtz Zentrum Geesthacht (HZG) at the German Bight, North Sea, within the Coastal Observing System for Northern and Arctic Seas (COSYNA). Here, they operationally retrieve continuous sea state and currents. In this work, ship reports from the Automatic Identication System (AIS) are the ground truth information used for evaluating HFSW radar system capabilities, while METOC data are directly acquired from COSYNA. Preliminary results are presented and discussed, together with outlines for future research
A novel approach to high frequency radar ship tracking exploiting aspect diversity
No full textLow-power High-Frequency Surface-Wave (HFSW) radars, designed for oceanic applications, are promising tools also for long-range surveillance in open-water Multi-Target Tracking (MTT) applications. This paper focuses on the fusion of multiple aspects over single-perspective systems. The single-sensor tracking steps, made up by the Joint Probabilistic Data Association (JPDA) rule and the Unscented Kalman Filter (UKF), are followed by a Track-to-Track association and Fusion (T2TF) strategy. Tracking performance improvements are investigated using real data collected by two simultaneously operated HFSW-radars
Radar-derived Surface Current Fields along RV METEOR cruise track M158
No full textThe dataset contains near surface current fields observed between September 28, 2019, and October 22, 2019. Currents were derived from radar data acquired with a Hereon X-band marine radar (Horstmann et al., 2021). The radar was deployed on the research vessel Meteor during the research cruise M158 for the TRIATLAS project. The provided data reflects the eastward (u) and northward (v) component of the near surface current vector. The effective depth of the retrieved currents depends on the waves present (longer waves feel the current at greater depth). Here, the current data corresponds approximately to a depth between 2 m and 10 m
Oceanographic HF surface-wave radars for maritime surveillance in the German Bight
No full textIn maritime surveillance systems, providing realtime, clear and accurate pictures of wide areas is essential for the human decision-making process. In such a context, oceanographic high-frequency surface-wave (HFSW) radars could be cost-effective sensors for long-range early-warning ship detection and tracking. In this paper, multi-target tracking and data fusion techniques are applied to real data recorded by three low-power HFSW radars installed in the German Bight of the North Sea. Ship reports from the automatic identification system (AIS) are exploited as ground truth information for assessing system performances. Both in situ and model data are used to investigate the capabilities of the systems according to the variations of the meteorological and oceanographic conditions. Preliminary results are presented and discussed, together with an outline for future research studies
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