• Journal of the Institute of Convergence Signal Processing
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• v.18 no.1
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• pp.21-24
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• 2017

Passive millimeter wave (MMW) imaging penetrates clothing to detect concealed objects. The distances extraction to the concealed objects is critical for the security and defense. In this paper, we address a passive stereo 3 mm MMW imaging system to extract the longitudinal distance to the concealed object. The concealed object area is segmented and extracted by the k-means clustering algorithm with splitting initialization. The distance to the concealed object is estimated by the corresponding centers of the segmented objects. In the experimental two pairs (each pair for horizontal and vertical polarization) of stereo MMW images are obtained to estimate distances to concealed objects.

• The Journal of the Acoustical Society of Korea
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• v.42 no.4
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• pp.320-328
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• 2023

Underwater active target detection is vital for defense systems, requiring accurate detection and estimation of distance and velocity. Sequential transmission is necessary at each beam angle, but divided pulse length leads to range ambiguity. Multi-frequency transmission results in time-bandwidth product losses when bandwidth is divided. To overcome these problem, we propose a novel method using Generalized Sinusoidal Frequency Modulation (GSFM) for rapid target detection, enabling low-correlation pulses between subpulses without bandwidth division. The proposed method allows for rapid updates of the distance and velocity of target by employing GSFM with minimized pulse length. To evaluate our method, we simulated an underwater environment with reverberation. In the simulation, a linear frequency modulation of 0.05 s caused an average distance estimation error of 50 % and a velocity estimation error of 103 % due to limited frequency band. In contrast, GSFM accurately and quickly tracked targets with distance and velocity estimation errors of 10 % and 14 %, respectively, even with pulses of the same length. Furthermore, GSFM provided approximate azimuth information by transmitting highly orthogonal subpulses for each azimuth.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.538-540
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• 2015

안전 거리 미확보는 교통 사고 원인 중 3위에 이르는 큰 위험 요소이다. 이러한 차간거리 미확보로 인한 사고는 조금만 빨리 대응하여도 사전에 방지할 수 있다. 따라서 주행 중 실시간으로 차간 거리를 추정하여 제공하는 시스템이 필요하다. 본 논문에서는 안드로이드 기반의 실시간 촬영 영상에서 차량의 에지와 후미등을 이용하여 차량을 검출하고, 검출된 차량의 폭을 이용하여 차간 거리를 추정하여 제공하는 시스템을 제안하고, 구현 결과를 제시한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.659-661
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• 2011

최근 WPAN 분야의 솔루션인 IEEE 802.15.4a는 저소비 전력으로 통신과 거리측정을 동시에 가능케 하는 PHY 제정을 목표로 하고 있다. 본 논문은 IEEE802.15.4a 물리계층에서 사용하는 UWB 신호를 대상으로 거리인식 시스템을 위한 Link Budget을 분석한다. 거리인식 시스템의 성능은 무선 채널의 다중경로 프로파일에도 관계된다. 따라서 본 연구에서는 IEEE 802.15.4a 채널 특성인 Residential 및 Office 환경을 고려하여 거리인식 시스템을 위한 Link Budget을 분석하였으며 연구된 내용은 다양한 거리추정 방식에 적용하여 거리추정 정밀도 향상에 기여할 수 있을 것이다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.7
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• pp.532-539
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• 2018

A position estimation technique is presented for a missile using high-resolution range profiles obtained by three wideband radars. Radar measures a target range using a reflected signal from the surface of a missile. However, it is difficult to obtain the range between the radar and the origin of the missile. For this reason, the interior angle between the moving missile and tracking radar is calculated, and a compensated range between surface of the missile and its origin is added to the tracking range of the radar. Therefore, position estimation of a missile can be achieved by using three total ranges from each radar to the origin of the missile. To verify the position estimation of the missile, electromagnetic numerical analysis software was used to prove the compensated range according to the flight position. Moreover, a wideband radar operating at 500-MHz bandwidth was applied, and its range profile was used for the position estimation of a missile.

• The Journal of the Acoustical Society of Korea
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• v.26 no.4
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• pp.166-172
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• 2007

In this paper, we address the target positioning performance of Multi-Static sonar with respect to target positioning method and measurement error. Based on the analysis on two candidate solution approaches, namely, Least Square (LS) using range and angular information simultaneously and Maximum Likelihood (ML) using only range information as the existing information fusion methods for possible application to Multi-Static sonar, we propose to employ ML using range and angular information. Assuming that each sensor can receive range and angular information, we conduct representative comparison experiments over the existing and proposed methods under various measurement noise scenarios. We also investigate the target positioning performance according to number of sensors, distance between transmitter and receiver. According to the experimental results, RMSE of the proposed ML with distance and direction information is found to be more superior to ML using distance alone and to LS in case distance between transmitter and receiver is longer and number of receiver is smaller.

• Proceedings of the Korea Contents Association Conference
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• 2012.05a
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• pp.33-34
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• 2012

무선 센서 네트워크의 다양한 응용에 있어 센서 노드의 지리학적 위치 측정은 매우 중요하다. 이를 위해 비-거리(Range-Free) 기반 위치 측정 기법에 대한 연구가 활발하게 진행 중이며, 비 균일 네트워크 환경에서 위치 정확도를 향상하기 위한 밀집 확률 기반의 위치 측정 기법이 제안되었다. 밀집 확률 기반의 위치 측정 기법에서 추정 거리 산출 시 노드 통신 반경 내 1-홉 거리는 모두 동일한 값을 갖는데 이는 반경 내 가까운 이웃 노드와 먼 이웃 노드가 있어도 모두 같은 거리로 추정하기 때문에 위치 측정 시 오차가 발생 할 수 있다. 따라서 본 논문에서는 이러한 오차를 줄이기 위해 각 노드마다 거리 추정 후 센싱 반경을 조절하여 2차 지역 거리 평가를 통해 센서의 위치를 측정하는 기법을 제안한다. 성능평가 결과, 제안하는 기법이 기존 기법에 비해 측위 정확도가 크게 향상되었다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.357-358
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• 2018

The track radar use the range track loop to track the target range. The bandwidth of the radar range tracker can be determined by tradeoff according to signal to noise ratio and the target range. On the other hand, electronic warfare is carried out to prevent the radar from tracking targets by electronic attack. The deception or noise jamming in electronic warfare can be performed to interfere with the range track loop of the radar. In order to efficiently perform electronic warfare, the bandwidth in radar tracking loop is estimated and can be used for electronic attack. To do this, we have studied the method of estimating the bandwidth of radar tracking loop using the variables that can be gathered in electronic warfare.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.2
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• pp.146-153
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• 2013

The IR-UWB radar system radiates a pulse whose width is several hundred pico sec at Tx antenna and check the time to receive the pulse that reflected from target to measure the TOA. In this paper, we present a new algorithm which supplement the conventional ranging algorithm for more accurate estimation. We get received signal data using IR-UWB Radar module which equipped a NVA6000 UWB Transceiver and analysis the data of multi-path. Consequently, we found the property of UWB multi-path signal, which best fit a Gamma distribution. so we present a algorithm using Gamma-distribution and compared a performance with conventional ranging algorithm.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.49 no.2
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• pp.130-136
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• 2012

In this paper, we propose a near-field range estimation method for a uniform linear array that can calibrate bearing estimation error which give a bad influence on a range estimation process. When a range is fixed, the bearing error is calibrated to maximize the beamformer output by the proposed algorithm based on the gradient method. Simulation results show that the proposed algorithm can compensate the bearing error which is less than the mainlobe beamwidth so that reduce the range estimation error as similar as the case of no bearing error.