• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.56-56
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• 2000

In this paper, the relationship between GPS code and carrier tracking performance is given. Through the error analysis and experiments, the performance of code tracking loop can be improved using narrow correlation. The performance of code tracking loop can be also improved if the better carrier tracking loop is used. On the other hand, the performance of carrier tracking loop is independent of that of code tracking loop.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10e
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• pp.109-111
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• 2002

군용시스템이었던 GPS가 1984년 민간에게 무료사용이 허용된 이후로 현재 위치추적기술과 이를 이용한 서비스가 많이 소개되고 있다. 하지만 이러한 서비스를 이용하기 위해서는 GPS단말기나 교환기, 수신기 등의 장비를 추가적으로 구매해야하는 비용부담이 생길 수밖에 없다. 따라서 거의 누구나 소지하고 있는 이동통신기기 또는 PDA를 사용함으로써 비용부담을 덜고 물류서비스의 효율성을 극대화시킬 수 있다. 본 논문에서는 이동통신기기나 PDA의 위치추적기능을 물류서비스에 적용하여 비용절약을 꾀하고 이동근무자나 차량의 위치를 실시간으로 파악하고 업무지시나 고객의 요구에 신속히 대응하는 효율적인 위치기반 물류 시스템을 설계하였다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.9
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• pp.943-953
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• 2009

In this paper, we propose a radio sensor to measure the position of the sun for the solar tracker of a photovoltaic system. In order to satisfy the requirement for the measurement accuracy within ${\pm}5^{\circ}$, the sensor receiver with high gain, high sensitivity and wide bandwidth is designed and implemented. The receiver has the bandwidth of 104 MHz, the system gain of 69 dB and the sensitivity of 0.46 K at 5.1 GHz. The processes of design and implementation of the radio sensor receiver are described in this paper. The effectiveness of the proposed radio sensor in the measurement of the position of the sun is demonstrated experimentally under the condition of cloud cover. The results show the radio sensor can measure the position of the sun within the accuracy of ${\pm}4^{\circ}$ successfully.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.2
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• pp.152-161
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• 2009

As follow jamming signals in a FHSS system cause malfuctioning in the code tracking circuits using early-late gates, we need a code tracking circuit that is robust against the follow jamming signals. In this paper, we propose a code tracking circuit using a linear clipper-Gaussian filter algorithm to remedy the malfunctioning due to the follow jamming signals in FHSS systems. We investigate the mechanism of the malfunctioning of the code tracking circuit and verify that the proposed linear clipper-Gaussian filter metigates the problem through mathematical analysis and computer simulations.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.12
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• pp.101-108
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• 2005

The GPS(Global Positioning System) receiver for satellite launch vehicles which will be mounted on a launch vehicle can be applied to the flight safety system with its accurately calculated position and velocity data during vehicle's flight. This paper analyzes the performance of the GPS receiver such as SNR(Signal to Noise Ratio), fix mode, position and velocity error, number of visible and tracking satellites, and PDOP(Position Dilution of Precision) under temperature variation which is changed from -34$^{\circ}C$ to +71$^{\circ}C$.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.1017-1019
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• 2015

본 논문에서는 블루투스 비콘을 이용한 스마트팩토리 물류추적시스템에서 복수개의 수신 단말기에서 복수개의 비콘 디바이스의 정확한 위치 인식을 위해 디바이스 모드 제어 방법에 대해 연구하였다. 이를 위해 블루투스 4.0 비콘 IPS 서비스를 활용한 비콘 디바이스 이동 추적, 3축 가속도 센서를 활용한 비콘 디바이스 이동 감지, 비콘 디바이스 이동 감지를 통한 블루투스 모드 제어 실험을 진행하였다. 실험을 통해 비콘 디바이스에 구성된 가속도 센서의 데이터를 활용하여 비콘 신호 전송을 제어할 수 있으며, 신호강도(RSSI) 값을 근거로 비콘 디바이스의 이동 경로와 위치 추적이 가능함을 확인하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.6
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• pp.1653-1658
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• 2008

In this paper, it is analyzed propagation distribution characteristics of radio wave, which is radiated on all sides from Access Point device for estimating scheme of wireless AP without GPS receiver environment. To tracking AP device is traced from wireless terminals and wireless terminal is traced from fixed AP devices, above all it is important to analysis the characteristics of receiving power in according to distance. Therefore in this paper, radio propagation characteristics of 2.4GHz wave is analyzed effect extent and quality in according to distance in doors and out doors, and utilized to location estimation.

• Journal of Advanced Navigation Technology
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• v.15 no.6
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• pp.1241-1249
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• 2011

There are TOA, TDOA and AOA method to estimate the position of the electromagnetic wave transmitter by using the multiple receivers at the fixed position. Among these methods, AOA method is suitable for the jammer localization system. Because TOA method can be adopted for the clocks of the transmitter and the receiver are synchronized each other, and TDOA method can be only adopted for a broad-band jamming signal. This paper, therefore, analyzes the characteristics of the AOA measurements and the sensitivity of the positioning performance according to the system design parameters. Based on the analyzed results, the jammer localization system to meet the desired performance is designed, and it has been checked that the positioning error for the jammer located at a distance of 10km is lower than 38m through the simulation results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.11 s.114
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• pp.1058-1064
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• 2006

In this paper, the channel capacity of a specified wireless indoor multiple-input multiple-output(MIMO) channel is estimated by analyzing spatial characteristics of this channel using the three-dimensional ray tracing method, and a technique for deriving an optimized separation of multi-antenna elements is proposed. At first, the ray paths, the path losses, and the time-delay profile are computed using the three-dimensional ray tracing method in an indoor corridor environment, which has the line of sight(LOS) and non-line of sight(NLOS) regions. The ray tracing method is verified by a comparison between the computation results and the measurements which are obtained with dipole antennas, an amplifier and a network analyzer. Then, an MIMO system is positioned in the indoor channel environment and the ray paths and path losses are computed for four antenna-position combinations and various values of the antenna separation to obtain the channel capacity for the MIMO system. An optimum antenna-separation is derived by averaging the channel capacities of 100 receiver positions with four different antenna combinations.

• Journal of Advanced Navigation Technology
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• v.18 no.4
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• pp.312-318
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• 2014

The altitudes of GEO satellites are higher than those of GPS satellites. Therefore the visibility and the received power of GPS signals are totally different from those of the users near the Earth's surface. In this study, we analyzed the visibility of GPS signals received on GEO satellites. And we also developed a software GPS receiver that works on GEO satellites using CCMDB algorithm which is a weak signal receiver algorithm. GPS signals received on a GEO satellite are generated by a commercial hardware GPS simulator and used for the verification of the developed software GPS receiver. The mean 3D position and velocity error are calculated as 165.636 m and 0.5081 m/s.