• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.1
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• pp.291-296
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• 2006

The restrictions concerning the use of the radio waves have become severe, the marine radar with low spurious is being developed. Therefore, it is necessary to develop aids to navigation as a radar beacon can respond to new type of marine radar. Because the system of radar in the future is an indetermination, new radar beacon should correspond to old and new radar system during a transition period. New radar beacon that is also able to respond to pulse radar, pulse compression radar and FM-CW radar were considered in these years in Japan. The sign of the response of Morse code in a new system is generated by the delay synthesis system. Computer simulation and actual examination using trial circuit were curried out. A big possibility was set up in the development of the new radar beacon that was able to correspond to old and new radar system. These results and the state of new radar beacon is mentioned in this paper.

• 한국군사과학기술학회지
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• 제14권6호
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• pp.1138-1143
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• 2011

One of the critical items in radar testing is the ability to evaluate the performance of radar systems under real operational environments. But it takes lots of time and cost to operate real targets and analyze the test results due to a large amount of data based on these complicated environments. In this paper, the Radar Simulative T&E Lab. is introduced, and the test and analysis results of the developing radar for predicting the radar system performance are described in the Radar Simulative T&E Lab. This laboratory could be used to test the far-field characteristics of antenna radiation pattern and to perform an effective radar system test and evaluation using a simulative target generator under a low cost repeating test situation.

• 항공우주기술
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• 제10권1호
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• pp.116-121
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• 2011

나로우주센터 추적레이더가 획득한 실시간 위치 정보는 발사통제시스템에서 위치, 속도, 비행궤도 표시, 예상궤도 진입여부 및 안전을 위한 비행종료시점 판단 등의 중요한 데이터로 사용된다. 추적레이더에서 발사통제시스템으로 전송하는 표적의 위치 정보는 추적레이더 중심의 좌표값 데이터이며, 발사통제시스템에서 추적레이더로 전송하는 Slaving 데이터는 발사대 중심의 좌표값 데이터이다. 이렇듯 추적레이더와 발사통제시스템 간의 송수신 데이터는 각 시스템에 맞게 적절하게 좌표 변환이 수행되어야 한다. 본 연구에서는 나로우주센터 추적레이더 간의 상호 데이터 송수신 및 발사통제시스템과의 데이터 통신에 사용되는 각각의 좌표계 및 좌표계 간의 좌표 변환에 대해 기술하였다.

• 한국전자파학회논문지
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• 제26권6호
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• pp.546-554
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• 2015

초 광대역 레이더는 숨겨진 물체를 찾는데 많은 장점을 가지고 있기 때문에, 지표 투과 레이더나 수풀 투과 레이더와 같은 투과레이더에 널리 이용되고 있다. 초 광대역 레이더의 종류 중에 하나인 잡음 레이더는 간섭 환경에 강한 특성을 가지고 있다. 그러나 일반적인 잡음레이더는 고속의 아날로그 디지털 변환기가 필요하여 광대역 레이더로 제작하는데 어려움이 있다. 본 논문에서는 간섭에 강한 특징을 가지면서 고속의 아날로그 디지털 변환기가 필요하지 않은 가상 잡음 레이더 시스템이 연구되었다. 또한, 초 광대역 시스템이 저주파에서 구현되었고, 이는 실험으로 성능이 검증되었으며, 제안된 가상잡음 레이더 시스템의 개념도 증명되었다.

• Journal of electromagnetic engineering and science
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• 제12권4호
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• pp.234-239
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• 2012

This paper presents a compact K-band Doppler radar sensor for human vital signal detection that uses a radar configuration with only single coupler. The proposed radar front-end configuration can reduce the chip size and the additional RF power loss. The radar front-end IC is composed of a Lange coupler, VCO, and single balanced mixer. The oscillation frequency of the VCO is from 27.3 to 27.8 GHz. The phase noise of the VCO is -91.2 dBc/Hz at a 1 MHz offset frequency, and the output power is -4.8 dBm. The conversion gain of the mixer is about 11 dB. The chip size is $0.89{\times}1.47mm^2$. The compact Ka-band Doppler radar system was developed in order to demonstrate remote human vital signal detection. The radar system consists of a Ka-band Doppler radar module with a $2{\times}2$ patch array antenna, baseband signal conditioning block, DAQ system, and signal processing program. The front-end module size is $2.5{\times}2.5cm^2$. The proposed radar sensor can properly capture a human heartbeat and respiration rate at the distance of 50 cm.

• Journal of Multimedia Information System
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• 제5권4호
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• pp.245-256
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• 2018

This study estimated rainfall information more effectively by image signals through the information system of weather radar. Based on this, we suggest the way to estimate quantitative precipitation utilizing overlapped observation area of radars. We used the overlapped observation range of ground hyetometer observation network and radar observation network which are dense in our country. We chose the southern coast where precipitation entered from seaside is quite frequent and used Sungsan radar installed in Jeju island and Gudoksan radar installed in the southern coast area. We used the rainy season data generated in 2010 as the precipitation data. As a result, we found a reflectivity bias between two radar located in different area and developed the new quantitative precipitation estimation method using the bias. Estimated radar rainfall from this method showed the apt radar rainfall estimate than the other results from conventional method at overall rainfall field.

• 한국군사과학기술학회지
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• 제19권4호
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• pp.443-452
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• 2016

Current low-altitude radar system often fails to detect small unmanned aerial vehicles (UAV) because of their small radar cross section (RCS) compared with larger targets. As a potential alternative, a passive bistatic radar system has been considered. We study an optimal deployment problem for the passive bistatic radar system. We model this problem as a covering problem, and develop an integer programming model. The objective of the model is to maximize coverage of a passive bistatic radar system. Our model takes into account factors specific to a bistatic radar system, including bistatic RCS and transmitter-receiver pair coverage. Considering bistatic RCS instead of constant RCS is important because the slight difference of RCS value for small UAVs could significantly influence the detection probability. The paired radar coverage is defined by using the concept of gradual coverage and cooperative coverage to represent a realistic environment.

• Journal of Astronomy and Space Sciences
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• 제34권4호
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• pp.303-314
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• 2017

With increased human activity in space, the risk of re-entry and collision between space objects is constantly increasing. Hence, the need for space situational awareness (SSA) programs has been acknowledged by many experienced space agencies. Optical and radar sensors, which enable the surveillance and tracking of space objects, are the most important technical components of SSA systems. In particular, combinations of radar systems and optical sensor networks play an outstanding role in SSA programs. At present, Korea operates the optical wide field patrol network (OWL-Net), the only optical system for tracking space objects. However, due to their dependence on weather conditions and observation time, it is not reasonable to use optical systems alone for SSA initiatives, as they have limited operational availability. Therefore, the strategies for developing radar systems should be considered for an efficient SSA system using currently available technology. The purpose of this paper is to analyze the performance of a radar system in detecting and tracking space objects. With the radar system investigated, the minimum sensitivity is defined as detection of a $1-m^2$ radar cross section (RCS) at an altitude of 2,000 km, with operating frequencies in the L, S, C, X or Ku-band. The results of power budget analysis showed that the maximum detection range of 2,000 km, which includes the low earth orbit (LEO) environment, can be achieved with a transmission power of 900 kW, transmit and receive antenna gains of 40 dB and 43 dB, respectively, a pulse width of 2 ms, and a signal processing gain of 13.3 dB, at a frequency of 1.3 GHz. We defined the key parameters of the radar following a performance analysis of the system. This research can thus provide guidelines for the conceptual design of radar systems for national SSA initiatives.

• 한국항행학회논문지
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• 제27권5호
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• pp.574-579
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• 2023

레이다 비행시험은 다양한 조건의 표적, 클러터, 재밍을 모의하는데 많은 제약 사항이 있다. 따라서, 본 연구에서는 운용 시나리오에 따라 운용 모의 기능을 수행하는 레이다 비행 모의 장치를 개발하였다. 개발된 레이다 비행모의 장치는 레이다 빔 운용 모의, 레이다 동작 제어, 모의 신호 발생, 비행자세모의를 통해 레이다의 다양한 임무 환경을 모의한다. 레이다 비행모의 장치는 레이다 임무 환경(클러터, 재밍 등)이 포함된 모의 표적(단일, 다중) 신호를 생성하고 변조하여 RF를 통해 레이다로 송신한다. 개발된 레이다 비행모의장치와 AESA 레이다를 연동하여, 다양한 비행 시나리오를 기반으로 하여 모의 표적을 탐지하고 탐지 결과 확인을 통해 레이다 성능을 검증하였다.

• 한국자동차공학회논문집
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• 제22권7호
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• pp.31-39
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• 2014

Recently, as Intelligent Transportation System (ITS) and self-driving system become influential in the ground transportation system, automotive radar systems have been actively studied among the various radar systems to implement the vehicle collision detection system and distance measurement system between vehicles. Most of the automotive radars are Frequency Modulated Continuous Wave (FMCW) radar type which can calculate distance and velocity of target by estimating the frequency difference between the transmitted signal and received signal. Therefore, accurate frequency estimation is very important in the FMCW radar system. For this reason, to improve the measurement accuracy of the FMCW radar, Reverse Directional FRI (RD-FRI) Super-Resolution technique which has high frequency estimation accuracy is applied to the FMCW radar system. The feasibility of the proposed technique is evaluated with simulation results and compared with FFT and conventional Super-Resolution techniques. The simulation results show that the proposed technique estimates the frequency with high accuracy and the distance with centimeter accuracy.