• Journal of Positioning, Navigation, and Timing
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• 제9권3호
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• pp.183-189
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• 2020

In emergency rescue situations, the localization accuracy of the rescue requestor is a very important factor in determining the success or failure of the rescue. Indoors where Global Navigation Satellite System (GNSS) is not operated, there is no choice but to use Wi-Fi or LTE signals. However, the performance of the current emergency rescue system utilizing those RF signals is exceedingly low. In this study, the effectiveness of the surface correlation technology using the accumulated signal pattern of RF signals was verified in relation to the emergency localization technology. To validate the proposed system, we configured and tested an emergency rescue scenario in multi-floors building. When the emergency rescue was requested, it was confirmed that the initial localization error was large owing to the short length of the accumulated signal pattern. However, the localization error decreased over time, which eventually led to the accurate location information being delivered to the rescuer.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.780-785
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• 1992

We present a multi-sensor fusion method in positioning control of a robot by using fuzzy logic. In general, the vision sensor is used in the gross motion control and the force/torque sensor is used in the fine motion control. We construct a fuzzy logic controller to combine the vision sensor data and the force/torque sensor data. Also, we apply the fuzzy logic controller to the peg-in-hole process. Simulation results uphold the theoretical results.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2012년도 춘계학술대회
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• pp.160-161
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• 2012

This paper is to develop & analyze the position & direction error equations in the free-gyro positioning & directional system by using two free gyros and is to find out the amount of the errors. First, the position & direction error equations are introduced and developed, based on the position & direction equations. Second, the value of errors is discussed based on sensors errors.

• 한국인터넷방송통신학회논문지
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• 제14권1호
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• pp.31-36
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• 2014

실내에서의 위치기반 서비스를 위한 실내 위치 인식 기술에 대한 연구가 활발하다. 음향 신호와 TDOA 기술을 기반으로 하는 3차원 위치 인식 시스템에 있어서, 마이크 센서의 개수와 배열 위치에 따라 추정된 위치의 오차 특성이 달라지므로, 본 논문에서는 마이크 센서의 배열과 측정된 거리 차이값의 오차 크기에 따른 추정 위치의 오차를 DOP로 분석하고, 그 추정 위치 오차 패턴과 추정 위치 오차값을 고려하여 최적의 마이크 배열을 결정하는 방법에 대해서 연구하였다.

• Journal of Ship and Ocean Technology
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• 제11권1호
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• pp.36-46
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• 2007

The maintenance of a ship is essential for safe navigation and hence regular surveys are prescribed according to the rule of classification societies. A hull inspection is generally performed by professional divers, but it takes a long time and the efficiency is low in terms of time and cost. In this research, a ROV(Remotely Operated Vehicle) named as SNU-ROV(Seoul National University-ROV) is developed to replace the conventional inspection method. In this system, the ROV is intended to be used for inspecting ship and harbor because harbor inspection is merging as a safety measure against any possible terror actions. In order to increase the efficiency of inspection, the ROV must be able to measure the exact position of damages. SNU-ROV has a positioning system based on LBL(Long Base Line). In shallow water such as harbor, however, LBL has bad DOP(Dilution of Precision) in the depth direction due to the limited depth. Thus LBL only can not locate the exact depth position. To solve the DOP problem, a pressure sensor is introduced to LBL and a complementary filter is attached by using indirect feedback Kalman filter. Thus developed positioning system is verified by simulation and experiment in towing tank.

• 한국지능시스템학회논문지
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• 제21권5호
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• pp.667-672
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• 2011

본 논문은 AGV(automatic guided vehicle)의 위치측정 정밀도 향상을 위해 UKF(unscented Kalman filter)를 이용한 위치 측정 센서의 융합 방법에 관한 연구이다. 기존의 AGV를 위한 유도 방법에는 유선 유도 방식과 마그네틱 유도 방식이 있었다. 이들은 정밀도가 높고 반응속도가 빠르기 때문에 대부분의 유연 생산 시스템에서 사용되어지고 있었다. 하지만 이러한 방법들은 유지 보수에 대한 지속적인 노력과 비용의 문제가 발생되었고 완성된 경로의 변경이 어렵다는 단점이 있었다. 이러한 문제들을 해결하기 위해, 최근에는 레이저 내비게이션을 이용한 유도방식으로 변경되고 있는 추세이다. 레이저 내비게이션은 벽면에 설치된 반사체를 측정하여 전역위치를 측정하는 장치로써 정밀도가 높고 경로 변경에 유연하다는 장점이 있다. 하지만 이 또한, 응답속도가 느리고 AGV의 주행 중 발생되는 반사체 계측 오차에 따라 위치측정 정밀도가 낮아진다는 단점이 있다. 이에 본 논문에서는 UKF를 이용하여 응답속도가 빠른 지역위치센서와 레이저 내비게이션의 센서융합 방법을 제안한다. 제안된 방법은 주행 중 발생되는 센서들의 오차를 분석하고 이에 따른 모델을 설계하여 위치측정 정밀도를 향상 시키는 방법이다. 본 논문에서는 실험을 위해서 직접 설계한 차축구동 방식의 지게차 AGV를 이용하여 제안한 방법의 결과와 레이저 내비게이션의 위치측정 결과를 비교하였다. 실험 결과, 제안된 방법이 레이저 내비게이션의 위치 측정 결과보다 16% 만큼 정밀도가 향상되는 것을 확인하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.1403-1406
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• 1997

Generally, G.P.S(Global Positioning System) is using for the car navigation system but it has some restrictions such as the discontinuity of earth satellites and SA (Selective Availability). Recently, the hybrid navigation system combining with G.P.S and Dead-reckoning are much attractuve for improving the accuracy of a vehicle positioning. G.P.S called satellite navigation system, can measure its position by using satellites. Dead-Reckoning is the self-contained navigatioin system using a wheel sensor for the vehicle velocity and a gyro sensor for the vehicle angular velocity. Some algorithm could be generated for finding the vehicle position and orientation. In this paper, we developed a hybrid algotithm wiht G.P.S DR and Map-Matching.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.1189-1190
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• 2008

Wireless sensor networks (WSN) have attracted much attention in recent years due to their potential use in many applications such as border protection and combat field surveillance. Given the criticality of such applications, maintaining a dependable operation of the network is a fundamental objective. However, the resource constrained nature of sensor nodes and the ad-hoc formation of the network, often coupled with an unattended deployment, pose non-conventional challenges and motivate the need for special techniques for dependable design and management of WSN. In this article, we highlight the potential of careful positioning of the base station (BS), which acts as a sink resources.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.615-616
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• 2008

Generally, distance between sensor nodes is measured using received signal strength indicator (RSSI) in wireless sensor network (WSN). Since RSSI is not absolutely accurate and stable in indoor environment, the performance of position estimation largely depends on estimation methods. In this paper, performance evaluation is presented to compare trilateration based positioning technique and collaborative ranging (CR) technique. From evaluation results, CR method is shown to be better than trilateration based method in terms of accuracy and precision.

• 소음진동
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• 제2권1호
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• pp.49-59
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• 1992

The motion analysis of a translation device driven by a piezoelectric actuator is performed to identify the mechanics of impact drive mechanism and to find the maximum speed waveform. The translation device is modeled as a semidefinite two-degree-of-freedom system. The motion analysis includes effects of friction force between moving mass and contact surface, dynamics of voltage amplifier and piezoelectric elements, and hysteresis of piezoelectric actuator. Base on the model, simulation studies are carried out and then compared with experimental results. It is found that the error between moving distances obtained by analysis and experiment is less than 15% and that the actual motion of moving mass is well predicted by the analytical work, finally, precision positioning experiments are carried out by using a proximity sensor as a feedback sensor. Position control of moving mass is initiated by the maximum speed waveform and finely tuned by the scaled down waveform so that accurate positioning is accomplished within the resolution of the sensor.