• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.45 no.3
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• pp.177-187
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• 2009

This paper describes a automatic video surveillance system(AVSS) with long range and 360$^{\circ}$ coverage that is automatically rotated in an elevation over azimuth mode in response to the TTM(tracked target message) signal of vessels tracked by ARPA(automatic radar plotting aids) radar. This AVSS that is a video security and tracking system supported by ARPA radar, CCTV(closed-circuit television) camera system and other sensors to automatically identify and track, detect the potential dangerous situations such as collision accidents at sea and berthing/deberthing accidents in harbor, can be used in monitoring the illegal fishing vessels in inshore and offshore fishing ground, and in more improving the security and safety of domestic fishing vessels in EEZ(exclusive economic zone) area. The movement of the target vessel chosen by the ARPA radar operator in the AVSS can be automatically tracked by a CCTV camera system interfaced to the ECDIS(electronic chart display and information system) with the special functions such as graphic presentation of CCTV image, camera position, camera azimuth and angle of view on the ENC, automatic and manual controls of pan and tilt angles for CCTV system, and the capability that can replay and record continuously all information of a selected target. The test results showed that the AVSS developed experimentally in this study can be used as an extra navigation aid for the operator on the bridge under the confusing traffic situations, to improve the detection efficiency of small targets in sea clutter, to enhance greatly an operator s ability to identify visually vessels tracked by ARPA radar and to provide a recorded history for reference or evidentiary purposes in EEZ area.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.2
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• pp.129-138
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• 2017

This paper has been shown for the extraction of Doppler signature from the radar signal for an air-breathing targets tracked in the ground radar. For the extractions, a Doppler resolution is confirmed from mathematical modeling of PT(pulse train) waveform. Doppler signatures of air-breathing target are varied to radar aspect angle of engine and are determined from physical parameter of jet engine. To confirm such Doppler signatures, the radar signal reflected from the air-breathing target is obtained by our radar signal storage. After this extraction, radar aspect angle of engine has estimated from tracking information. Relative differences of Doppler signatures to radar aspect angle of engine is verified from these results and Doppler profiles for radar target identification appliance are presented.

• IEMEK Journal of Embedded Systems and Applications
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• v.5 no.2
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• pp.93-102
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• 2010

The FMCW(Frequency Modulation Continuous Wave) radar possesses range-velocity ambiguity to identify the correct combination of beat frequencies for each target in the multi-target situation. It can lead to ghost targets and missing targets, and it can reduce the detection probability. In this pap er, we propose an effective identification algorithm for the correct pairs of beat frequencies and the signal processing hardware architecture to effectively support the algorithm. First, using the correlation of the detected up- and down-beat frequencies and Doppler frequencies, the possible combinations are determined. Then, final pairing algorithm is completed with the power spectrum density of the correlated up- and down-beat frequencies. The proposed hardware processor has the basic architecture consisting of beat-frequency registers, pairing table memory, and decision unit. This method will be useful to improve the radar detection probability and reduce the false alarm rate.

• Journal of the Korea Society for Simulation
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• v.29 no.4
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• pp.21-31
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• 2020

NCTR(Non-Cooperative Target Recognition) refers to the function of radar to identify target on its own without support from other systems such as ELINT(ELectronic INTelligence). ISAR(Inverse Synthetic Aperture Radar) image is one of the representative methods of NCTR, but it is difficult to automatically classify the target without an identification database due to the significant changes in the image depending on the target's maneuver and location. In this study, we discuss how to build an identification database using simulation and deep-learning technique even when actual images are insufficient. To simulate ISAR images changing with various radar operating environment, A model that generates and learns images through the process named 'Perfect scattering image,' 'Lost scattering image' and 'JEM noise added image' is proposed. And the learning outcomes of this model show that not only simulation images of similar shapes but also actual ISAR images that were first entered can be classified.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.50 no.1
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• pp.21-29
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• 2014

The dynamic information of radar and automatic identification system (AIS) for targets obtained from the traffic vessels operating in the north outer harbor and surrounding waters of Busan port, Korea. The target information was analyzed to investigate the potential collision risk resulting from the invalid true heading (HDT) information of AIS and the integration ambiguity in the graphic presentation of both tracked data sets for two systems. An integrated display system (IDS) for supporting the navigator of offshore fishing vessels was also developed to find possible maneuvering solutions for collision avoidance by comparing radar data with AIS data in real-time at sea. Consequently, the multiple functions of IDS can provide additional information that is potentially valuable for taking action to avoid the collision in offshore fishing vessels. However, the integration criteria of radar and AIS targets in the IDS must be carefully established to eliminate the fusion ambiguity in the graphic presentation of both AIS and radar symbols such as the one or two physical targets which are very close to each other.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.12 s.115
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• pp.1249-1258
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• 2006

Two-dimensional(2-D) radar images, namely, ISAR images from a maneuvering target include unwanted phase errors due to the target's motion. These phase errors make ISAR images to be blurred. The ISAR autofocus technique is required in order to remove these unwanted phase errors. Unless those unwanted phase errors produced by the target's motion are removed prior to target identification, we cannot expect a reliable target identification performance. In this paper, we use the entropy-based ISAR autofocus technique which consists of two steps: range alignment and phase adjustment. We analyze a relationship between the number of sampling point and a image quality in a range alignment algorithm and also analyze a technique for reducing computation time of the SSA(Stage-by-Stage Approachng) algorithm in a phase adjustment.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.4
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• pp.337-344
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• 2004

A real-time surveillance system of the inshore fishing ground was constructed to identify and detect discrete targets, such as illegal fishing vessels. This paper describes measurements made with a combination of sensors, such as radar, CCTV camera, and GPS receivers, for monitoring the fishing activity of small vessels within the fishing limit zones of the inshore waters. The CCTV camera system was used to confirm detection and to classify the type of target. The location of legal vessels distributed in coastal waters was acquired from each GPS system of ships connected to commercial satellite communication network. The surveillance system was networked via LAN to one host PC with the use of electronic navigational charts (ENC) and a radar link. Radar Target Extractor (RTX) for radar signal processing can be remotely accessed and controlled on existing PC via the internet, from anywhere, at any time. Results are presented that demonstrate the effectiveness of the newly constructed fisheries monitoring system for conducting continuous surveillance of illegal fishing vessels in the inshore fishing ground. The identification of illegal fishing vessels was achieved by comparing radar positions of illegal fishing vessels exceeding the warning limits in the surveillance area with GPS position reports transmitted from legal fishing vessels, and the illegal fishing vessels were marked with red symbols on the ENC screen of a PC. The methods to track the activities of all vessels intruding or leaving the fishing limit zones also were discussed.

• Journal of the Korean Operations Research and Management Science Society
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• v.40 no.2
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• pp.31-42
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• 2015

The purpose of airborne radars is to detect and identify approaching targets as early as possible. If the targets are identified as enemies, detection systems must provide defense systems with information of the targets to counter. Though many previous studies based on the detection theory of the target have shown various ways to derive detection probability of each radar, optimal arrangement of radars for effective detection, and determination of the search pattern, they did not reflect the fact that most military radar sites run multiple radars in order to increase the accuracy of identifications by radars. In this paper, we propose a model to analyze the probability of identification generated by the multiple radars using non-homogeneous absorbing markov chains. Our results are expected to help the military commanders counter the enemy targets effectively by using radars in a way to maximize the identification rate of targets.

• ETRI Journal
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• v.40 no.5
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• pp.592-603
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• 2018

In order to obtain better target identification performance, an efficient waveform design method with high range resolution and low sidelobe level for orthogonal frequency division multiplexing (OFDM) multiple-input multiple-output (MIMO) radar is proposed in this paper. First, the wideband CP-based OFDM signal is transmitted on each antenna to guarantee large bandwidth and high range resolution. Next, a complex orthogonal design (COD) is utilized to achieve code domain orthogonality among antennas, so that the spatial diversity can be obtained in MIMO radar, and only the range sidelobe on the first antenna needs suppressing. Furthermore, sidelobe suppression is expressed as an optimization problem. The integrated sidelobe level (ISL) is adopted to construct the objective function, which is solved using the Broyden-Fletcher-Goldfarb-Shanno (BFGS) algorithm. The numerical results demonstrate the superiority in performance (high resolution, strict orthogonality, and low sidelobe level) of the proposed method compared to existing algorithms.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.3
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• pp.294-303
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• 2008

ISAR(Inverse Synthetic Aperture Radar) images represent the 2-D(two-dimensional) spatial distribution of RCS (Radar Cross Section) of an object, and they can be applied to the problem of target identification. A traditional approach to ISAR imaging is to use a 2-D IFFT(Inverse Fast Fourier Transform). However, the 2-D IFFT results in low resolution ISAR images especially when the measured frequency bandwidth and angular region are limited. In order to improve the resolution capability of the Fourier transform, various high-resolution spectral estimation approaches have been applied to obtain ISAR images, such as AR(Auto Regressive), MUSIC(Multiple Signal Classification) or Modified MUSIC algorithms. In this study, these high-resolution spectral estimators as well as 2-D IFFT approach are combined with a recently developed ISAR image classification algorithm, and their performances are carefully analyzed and compared in the framework of radar target recognition.