• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.1
• /
• pp.306-310
• /
• 2012

Location tracking system represents position by searching objects and humans. In this paper I would like to write about RF chip support Zigbee which is called CC2420. In simulated network circumstance, we can get the information about mobile-node by sending it to sink-node. Position finding is in error by 3m at outdoor environment. The error scale is acceptable within easy range of naked eyes. It can be overcome by using GPS information and Google maps with the wireless networking background.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2013.10a
• /
• pp.432-434
• /
• 2013

본 논문의 실내위치측위시스템은 무선랜 환경에서 AP의 RSSI 신호를 수신하여 Friis 공식을 통해 거리로 산출되고, 산출된 거리는 삼각측량법에 의해 (x, y)좌표로 변환되어 현재의 위치를 나타낸다. 여기서 RSSI 신호는 신호잡음을 포함하고 신호잡음으로 인하여 실제 위치 측위 시 오차가 발생한다. 이러한, 오차를 보정하고 실내위치측위 정확도를 향상하기 위해 비선형시스템에서 사용하는 확장칼만필터를 적용하여 실험하였다. 본 실내위치측위시스템의 시스템모델은 선형이고 측정모델은 비선형이므로 효율적인 보정알고리즘인 확장칼만필터를 선택하고 실험은 MATLAB로 수행하였다. 실험결과 실내위치측위시스템의 정확도가 향상되었다.

• Journal of IKEEE
• /
• v.14 no.1
• /
• pp.25-32
• /
• 2010

In this paper, we analyze the location accuracy of real-time locating systems (RTLS) in multipath environments, where the RTLS complies with an ISO/IEC 24730-2 international standard. RTLS readers should have an ability not only to recover the transmitted signal but also provide arrival timing information from the received signal. In the multipath environments, in general, the transmitted signal goes through both direct and indirect paths, and then it becomes some distorted form of the transmitted signal. Such multipath components have a critical effect on deciding the first arrival timing of the received signal. To analyze the location error of the RTLS in the multipath environments, we assume two multipath components without considering an additive white Gaussian noise. Through the simulation and real test results, we confirm that the location error does not occur when the time difference between two paths is more than 1.125Tc, but the location error of about 2.4m happens in case of less than 0.5Tc. In particular, we see that the resolvability of two different paths depends largely on the phase difference for the time difference of less than 1Tc.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.26 no.4
• /
• pp.360-364
• /
• 1990

To testy time division scheme, we performed some experiments in a circular water tank(13m in diameter and 1m deep). A result of that is shown in figure 4. The 2-dimensional position of the pinger was calculated by the method of hyperbolic line of position calculation. The resolution of the time difference on the base line is 2.5cm. In experiments, the multiple pingers of a single frequency were distinguished and tracked successfully. When the experiment is carried out in the water tank, some multi-path pulses always occur. To delete it, several 10 ms of time delay is inserted onto the program after a group of the normal signals are received. Some normal pulses are not received by the time delay, however there is no problem, practically, for the distinction and the tracking of the pulse. In 2-dimensional positioning, the pinger position can be calculated with three hydrophones. However, if four hydrophones are available, the positioning accuracy will be higher than three hydrophones only by some techniques. Another good feature of the use of four hydrophones is that the positioning of the pinger is capable if a hydrophone fails in receiving them. We also tested this distinguishing method in the field using another type pingers(APPENDIXA).

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.47 no.4
• /
• pp.73-85
• /
• 2010

In dense electronic warfare signal environments, the conventional radar identification methods based on the basic parameters such as frequency, pulse width, and pulse repetition interval are confronted by the problem of identification ambiguity. To overcome this critical problem, a new approach introducing scan pattern of radars has been presented. Researches on new identification methods, however, suffer from a practical problem that it is not easy to secure the many radar signals including various scan pattern information and operation parameters. This paper presents a modeling method of radar signals with which we can generate radar signals including various scan pattern types according to the parameters determining the variation pattern of received signal strength. In addition, with the radar signals generated by the proposed model we analyze their characteristics according to the location of an electronic warfare support (ES) system.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.41 no.3
• /
• pp.103-114
• /
• 2004

This paper deals with a system that is capable of recognizing hand-signals in 3-dimensional space. The system uses 2 color cameras as input devices. Vision-based gesture recognition system is known to be user-friendly because of its contact-free characteristic. But as with other applications using a camera as an input device, there are difficulties under complex background and varying illumination. In order to detect hand region robustly from a input image under various conditions without any special gloves or markers, the paper uses previous position information and adaptive hand color model. The paper defines a hand-signal as a combination of two basic elements such as 'hand pose' and 'hand trajectory'. As an extensive classification method for hand pose, the paper proposes 2-stage classification method by using 'small group concept'. Also, the paper suggests a complementary feature selection method from images from two color cameras. We verified our method with a hand-signal application to our driving simulator.

• Journal of Advanced Navigation Technology
• /
• v.18 no.1
• /
• pp.90-94
• /
• 2014

This paper suggests the system that allows nearby firefighters to read about the transmission direction of a distress signal and track the location by RSSI of received distress signal which is transmitted wirelessly after sensing the distress signal of a firefighter using the Wireless Sensor Network(WSN) based on IEEE 802.15.4 and Received Signal Strength Indicator(RSSI) in the building. Also, It was confirmed that the location tracking using RSSI is possible because the difference between theoretical value and experimental value is little when experiment using the proposed system.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2019.07a
• /
• pp.237-238
• /
• 2019

현시대에 자율주행 기술이 자동차를 단순 이동수단에서 이동성을 확보한 생활공간으로 자동차의 근본적인 개념을 변화시켜 새로운 산업 패러다임적 가치뿐 아니라, 사회 경제적 변혁을 예고하고 있다. 이미 전 세계적인 기업들은 자율주행 시스템을 구축하고 개발하여 실제 생활에서 활용도 하고 있다. 그럼에도 불구하고 상용화를 하기 위해선 아직 법/제도의 부재, 안정성, 가격 등 여러부분에서 문제점들을 극복해야한다. 본 과제인 라인트레이서와 GPS를 활용한 자율주행시스템이 목적지를 지정하면 자율적으로 길이나 도로를 따라 이동하면서 장애물을 피해가게 만들어 안정성을 확보하고 이동하는 시간에 개인 여가 시간이나 생산적인 활동을 할수 있게 만들어 삶의 질 개선에 기여할 것이다. 이러한 기술들을 적극 활용하여 목적지를 설정하면 자율주행 하는 자동차로 설정하였고, 장애물 감지와 현재 방향 감지를 추가하였다. 장애물 감지와 방향 그리고 위치를 수신받기 위해 5개의 센서를 활용하였고 한번에 구동을 시키기 위해 센서 쉴드를 활용하여 기능을 확장 시켰다.

• Journal of Digital Convergence
• /
• v.14 no.2
• /
• pp.217-225
• /
• 2016

In this study, a dementia patient care monitoring system is suggested that uses a wearable type bluetooth beacon to prevent them from going missing. This system shows whether the patients stay within the manageable area and sends a warning message to their monitoring managers' or guardians' smart devices when they leave it. The feature of the system is that it provides the service based on indoor location that makes the beacon worn by dementia patients continuously transmit their location information to the managing server through the smart terminal installed indoors or in hospitals and that enables the monitoring managers or the guardians to receive messages sent from the server that tell the patients' whereabouts through their smart devices. The system suggested in this paper is believed to be a system that effectively contributes to the prevention of the dementia patients' going astray from the hospitals and facilities where they are taking care.

• Journal of Digital Convergence
• /
• v.12 no.11
• /
• pp.373-378
• /
• 2014

The technology of direction finding is very important to make high position fixing accuracy. TDOA(time difference of arrival) direction finding technology is a high accuracy technology and is used in RF system from 1990. The principle of TDOA is to receive an emitter signal with two antennas, measure the time difference of received signal and then convert the time differences to azimuth angle. For high DF(direction finding) accuracy long basis line and high SNR at receiving system are needed. The DF accuracy and position fixing accuracy are simulated with different SNRs and antenna base lines. We obtain the DF accuracy of $0.51^{\circ}$ at $0^{\circ}$ incident azimuth angle in case of 50m base line and 40dB SNR.