• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2012.10a
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• pp.128-130
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• 2012

One of the hot issues on GNSS might be that China declared to broadcast the signal of the new Global Navigation Satellite System called Beidou-Compass in December 2011. The multi-GNSS systems with the existing GPS and GLONASS consist of more than 100 GNSS satellites and transmit their signals in near future. Many benefits are expected in accuracy, availability, integrity and increasing anti-jam performance. In this presentation, we have mainly investigated the latest issue for multi- GNSS and discussed spectrum analysis as well as the accuracy improvement issue. The use of the modern weapon system based on satellite navigation information was also briefly investigated in warfare.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.80-80
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• 2000

The GPS can provide accurate position information on the earth. But GPS receiver can't give position information inside buildings. DR(Dead-Reckoning) or INS(Inertial Navigation System) gives position information continuously indoors as well as outdoors, because they do not depend on the external navigation information. But in general, the inertial sensors severely suffer from their drift errors, the error of these navigation system increases with time. GPS and DR sensors can be integrated together with Kalman filter to overcome these problems. In this paper, we developed a personal navigation system which can be carried by person, using GPS and electronic pedometer. The person's footstep is detected by an accelerometer installed in vertical direction and the direction of movement is sensed by gyroscope and magnetic compass. In this case the step size is varying with person and changing with circumstance, so determining step size is the problem. In order to calculate the step size of detected footstep, the neural network method is used. The teaming pattern of the neural network is determined by human walking pattern data provided by 3-axis accelerometer and gyroscope. We can calculate person's location with displacement and heading from this information. And this neural network method that calculates step size gives more improved position information better than fixed step size.

• Journal of Navigation and Port Research
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• v.33 no.2
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• pp.99-104
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• 2009

The Kinematic GPS is well known to provide a quite good accuracy of positioning within an level. Although kinematic GPS assures high precision measurement on the basis of an appreciable distance between a reference station and an observational point, it has measurable distance restriction within 20 km from a reference station on land. Therefore, it is necessary to make out a simple and low-cost method to obtain accurate positioning information without distance restriction In this paper, the velocity integration method to get the precise velocity information of a ship is explained. The experimental results of Zig-zag maneuver and Williamson turn as the ship's maneuvering test, and other experimental results of ship's movement during leaving and entering the port with low speed were shown. From the experimental results, ship's course, speed and position are compared with those obtained by kinematic-GPS, velocity integration method and dead reckoning position using Gyro-compass and Doppler-log.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2006.10a
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• pp.49-55
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• 2006

Kinematic GPS provides quite good accuracy of position in cm level. Though K-GPS assures high precision measurement in cm level on the basis of an appreciable distance between a station and an observational point, but it has measurable distance restriction within 20 km from a reference station on land. So it is necessary to make out a simple and low-cost method to obtain accurate positioning information without distance restriction. In this paper, the velocity integration method to get the precise velocity information of ship is explained. Next two experimental results (Zig-zag maneuvering test and Williamson turn) as the ship's maneuvering test and also the experimental results of leaving and entering port as slow speed ship's movement were shown. In these experimental results, ship's course, speed and position are compared with those obtained by kinematic-GPS, velocity integration method and dead reckoning position using Gyro-compass and Doppler-log.

• Journal of Biosystems Engineering
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• v.36 no.2
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• pp.116-121
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• 2011

This study was conducted to develop a robust navigator which could be in positioning for precision farming through developing a plural GPS receiver with 4 sets of GPS antenna. In order to improve positioning accuracy by integrating GPS signals received simultaneously, the algorithm for processing plural GPS signal effectively was designed. Performance of the algorithm was tested using a simulation program and a fixed point on WGS 84 coordinates. Results of this study are aummarized as followings. 1. 4 sets of lower grade GPS receiver and signals were integrated by kalman filter algorithm and geometric algorithm to increase positioning accuracy of the data. 2. Prototype was composed of 4 sets of GPS receiver and INS components. All Star which manufactured by CMC, gyro compass made by KVH, ground speed sensor and integration S/W based on RTOS(Real Time Operating System)were used. 3. Integration algorithm was simulated by developed program which could generate random position error less then 10 m and tested with the prototype at a fixed position. 4. When navigation data was integrated by geometrical correction and kalman filter algorithm, estimated positioning erros were less then 0.6 m and 1.0 m respectively in simulation and fixed position tests.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2003.02a
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• pp.508-513
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• 2003

정보화 농업기술의 발전에 따라 효율적인 농작물의 관리와 농작업의 기계적 제어를 위하여 위치정보의 필요성이 점차 증가하고 있다. 1990년대 말부터 위치정보를 기반으로 한 정밀농업 기술의 확산에 따라 측위시스템을 탑재한 농작업기의 생산과 보급이 급속히 늘어나고 있다. 미국의 경우, 생산 콤바인의 70%가 GPS(Global Positioning System)를 장착하여 출하되고 있다. GPS의 경우 정밀도에 따라 수 십만 원에서 수천만 원에 이르기까지 가격의 편차가 매우 심하며 구미의 경우 약 1m이내의 측위 오차범위를 갖는 수백 만원 정도의 수신기를 농기계에 탑재하여 이온하고 있다. (중략)

• IEMEK Journal of Embedded Systems and Applications
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• v.3 no.3
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• pp.126-135
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• 2008

The development of an unmanned vehicle basically requires the robust and reliable performance of major functions which include global localization, lane detection, obstacle avoidance, path planning, etc. The implementation of major functional subsystems are possible by integrating and fusing data acquired from various sensory systems such as GPS, vision, ultrasonic sensor, encoder, and electric compass. This paper focuses on implementing the functional subsystems, which are designed and developed by a graphical programming tool, NI LabVIEW, and also verifying the autonomous navigation and remote control of the unmanned vehicle.

• Proceedings of the Korean Society of Computer Information Conference
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• 2011.06a
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• pp.331-332
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• 2011

본 논문은 위치 측정 안드로이드 프로그램과 각도 측정 안드로이드 프로그램 구현 사례를 소개한다. 구현한 프로그램을 갤럭시 S에서 실험한 결과도 소개하고 갤럭시 S2에서 실험한 결과도 소개한다. 근래에 상황기반 서비스와 증강현실 서비스가 널리 연구되고 있는데 본 연구는 이러한 실용 시스템 개발의 첫 걸음이다.

• Electronics and Telecommunications Trends
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• v.23 no.4
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• pp.137-146
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• 2008

위성항법수신기는 항법위성(GPS)들이 현재 위치와 시간이 담긴 전파신호를 지상으로 송신하면, 이런 신호를 받아 전파가 도달하기까지 걸린 시간을 계산해 자신의 현재 위치를 파악하게 된다. 경도와 위도, 높이를 동시에 파악하기 위해서는 3개 위성신호가 요구되고, 위성간 시간 오차를 제거해 위치 측정의 정확도를 높이기 위한 신호용으로 또 하나의 위성이 필요해 4개 위성이 요구된다. 항법의 형태는 육표기반 항법, 천체기반 항법, 센서기반 항법, 무선기반 항법 및 위성기반 항법으로 분류되며 그 중 전역이고 간섭 영향 및 재밍(jamming)이 어려우며 정확도 측면에서 우수한 위성항법시스템에는 GPS(미국), GLONASS(러시아)가 운용중이고, Galileo(유럽연합), COMPASS(중국), QZSS(일본), IRNSS(인도)이 개발중이다. 위성항법시스템 다원화에 따라 위성항법 수신기 기술도 이중주파수처리 및 타 시스템과의 호환성 제공이 요구되는바, 본 논문에서는 위성항법 수신기 기술 동향을 소개하고자 한다.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.2
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• pp.97-103
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• 2016

In this paper, a smartphone-controlled personal mobility system (PMS) with semi-autonomous navigation is developed. The proposed PMS moves to waypoints and then reaches the destination where the waypoints and destination are selected by the user using Google maps in a smartphone. The hardware environment consists of a GPS (Global Positioning System) in the smartphone and a compass sensor. In addtion, while it is moving in autonomous mode, the user can intervene and change the direction and speed of the PMS in order to avoid obstacles that may be encountered accidentally in a dynamic environment. That is why it is called "semi-autonomous navigation". Experimental results showed that the proposed PMS is effectively able to migrate to the waypoints and destination in both autonomous and manual modes.