• Title/Summary/Keyword: GPS time

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An Instantaneous Integer Ambiguity Resolution for GPS Real-Time Structure Monitoring (GPS 실시간 구조물 모니터링을 위한 반송파 관측데이터 순간미지정수 결정)

  • Lee, Hungkyu
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.34 no.1
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    • pp.341-353
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    • 2014
  • In order to deliver a centimeter-level kinematic positioning solution with GPS carrier-phase measurements, it is prerequisite to use correctly resolved integer ambiguities. Based on the mathematical modeling of GPS network with application of its geometrical constraints, this research has investigated an instantaneous ambiguity resolution procedure for the so-called 'integer constrained least-squares' technique which can be effectively implemented in real-time structure monitoring. In this process, algorithms of quality control for the float solutions and hypothesis tests using the constrained baseline for the ambiguity validation are included to enhance reliability of the solutions. The proposed procedure has been implemented by MATLAB, the language of technical computing, and processed field trial data obtained at a cable-stayed bridge to access its real-world applicability. The results are summarized in terms of ambiguity successful rates, impact of the stochastical models, and computation time to demonstrate performance of the instantaneous ambiguity resolution proposed.

A Implementation of GPS applied Time-Synchronizer for PC based DVR (PC based DVR의 시각동기를 위한 GPS 시각동기유지시스템의 구현)

  • Lee, Gyung-Soo;Park, Kwang-Chae
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2007.10a
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    • pp.593-599
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    • 2007
  • PC based DVR replaces existing analog CCTV system therefore expands the field and DVR is used for monitoring and security so it requires exact time(clock). But DVR system can't maintains exact clock causing several reasons. For providing exact time information we should use additional system. For economical and usable environment, using GPS system is most suitable suggested solution than use WAN(Wide Area Network). Therefore in this paper for analysis the result of PC based DVR's system clock using GPS system, 1) clock source receiving module that receives the clock form GPS satellite and 2) GPSW H/W units that provide clock source to PC Based DVR 3)Daemon software named PCSW which adjust PC's clock so system could reduced the clock difference with UTC clock and measured the result.

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Real Time Monitoring of Cars during European Rally Championships in Poland in 2005

  • Bartlomiej, Oszczak;Cezary, Specht;Stanislaw, Oszczak;Sitnik, Eliza
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.1
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    • pp.241-246
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    • 2006
  • The paper presents the preparations work and experiences gained from realtime GPS car monitoring during the European Rally Championships organized on 10-12 June 2005 in Poland. The developed system is based on GPS and GSM/GPRS technology. Distribution and teletransmission of data are possible using different GSM operators in Poland, which makes the system fully independent. The system's server collects data from rally cars, processing and send data through VPN connections to the SQL server located in main control room. Data can be collected in real time via Internet or GPRS. Some information on GSM/GPRS range during rally championships are also presented in the paper. The study covered many trials and tests of different software and various configurations of the GPRS modems before finally the system started to work. Information coming from 10 Rally Cars were collected to the SQL Server continuously in one second interval. In real time mode these all data were displayed simultaneously in the rally main control room and in the rally press conference room. Paper describes also adopted emergency procedures and remote reconfiguration of GPS/GPRS boxes inside rally cars made during championships. Some problems and method of practical solutions are presented to avoid active jamming dangerous for a driver and his pilot, having system of communication intercoms jammed by teletransmission of GPRS 900/1800 MHz. In cooperation with rally teams special GPS/GPRS safety boxes were designed and made. Monitoring of all 7 rally stages with GPS receivers and method of calibrations of the maps were presented. GSM signal coverage was also checked in all stages. All data transmitted from rally cars were recorded in the computer. Some of our GPS cars had accidents and dispite them information were continuously sent to server. There is possibility to show in post mission mode the position of chosen cars in our rally application. Some information of best rally cars are presented also in the paper.

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Structure Deformation Check with GPS and IMU (GPS와 IMU에 의한 구조물 변형 검색)

  • 김진수;박운용;장상규;안상준
    • Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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    • 2004.04a
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    • pp.113-117
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    • 2004
  • Such social structures as bridges, buildings, dams and towers have been transformed by their own load or fundamental ground. They have been behaved by other external causes. These regular or irregular behaviors threaten to do their users safety. Therefore, to monitor the load of the structures or reaction shown by them could help to verify their behaviors. RTK GPS allows the use of a static base station and remote rover unit to allow for data collection within several seconds and in real time. It is useful for monitoring the behaviors of massive structures like bridges. In this Study, Among GPS methods, we used RTK GPS to analyze the precision of monitoring and then on the basis of it, we developed a monitoring system using RTK GPS when measured the behavior of main tower of a suspension bridge by using RTK GPS. Comparing a deviation between observation values, X axis was 1mm, Y axis was 1mm and Z axis 2.2mm. It turned out that it was possible to monitor and measure structures by RTK GPS.

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Accuracy Analysis of RTK-GPS Rover Speed in Route Surveying (RTK-GPS에 의한 노선측량에서 이동국의 속도에 따른 정확도 분석)

  • 최병길;이형수
    • Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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    • 2004.04a
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    • pp.139-144
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    • 2004
  • This study aims to analyze the accuracy of rover speed change in route surveying using RTK-GPS. Route surveying methods using GPS contain Static, DGPS, and RTK-GPS. Much research of navigation system, positioning of vehicles by DGPS, and accuracy analysis by GPS surveying have already been done. From this study, it is firstly found that DGPS is suitable for car navigation and sea navigation with an error of meter scale but not good for detailed construction, designing maps and updating GIS databases. Secondly, RTK-GPS can be used for managing gas pipes, water supply and drain pipes and fiber-optic cable that are needed to be controlled in a real time basis. Thirdly, since the accuracies of route surveying by RTK-GPS and DGPS are not correctly matched with the change of rover speed, the choice of route surveying method from those two should follow the need of accuracy fidelity Further study should focus on Cycle Slip problem and coordinate change problem in tunnel and mountainous areas.

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Analysis of the Combined Positioning Accuracy using GPS and GLONASS Navigation Satellites

  • Choi, Byung-Kyu;Roh, Kyoung-Min;Lee, Sang Jeong
    • Journal of Positioning, Navigation, and Timing
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    • v.2 no.2
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    • pp.131-137
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    • 2013
  • In this study, positioning results that combined the code observation information of GPS and GLONASS navigation satellites were analyzed. Especially, the distribution of GLONASS satellites observed in Korea and the combined GPS/GLONASS positioning results were presented. The GNSS data received at two reference stations (GRAS in Europe and KOHG in Goheung, Korea) during a day were processed, and the mean value and root mean square (RMS) value of the position error were calculated. The analysis results indicated that the combined GPS/GLONASS positioning did not show significantly improved performance compared to the GPS-only positioning. This could be due to the inter-system hardware bias for GPS/GLONASS receivers, the selection of transformation parameters between reference coordinate systems, the selection of a confidence level for error analysis, or the number of visible satellites at a specific time.

A Study on Development of GPS Simulation Tool Kit (GPS Simulation System 개발에 관한 연구)

  • 양원재;전승환
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 1998.10b
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    • pp.65-73
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    • 1998
  • Ship's positino data obtaining method is ine of the very important factor innavigation . Nowadays, GPS(Global Positioning System) using the earth orbiting satellites are equipped and operated for the position finding. Because it provides more precise position information than other equipments and is very convenient for navigator. In this study, it is designed to develop the GPS simulator for everybody being able to proactise the GPS operating skill like as navigation planning, navigation calculating etc. And also, it can be operated with personal computer without real GPS receiver. This simulation system is based on the real GPS receiver system and built by the visual basic 5.0 program. And it displays the ship's position and navigating information and plots the ship's moving track on the screen in real time according as initial setup data-main engine's rpm, rudder angle, depature position and waypoint.

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Real time GPS position data correction using the vanishing point and a monocular vision system for autonomous land navigation (무한원점과 단일 비젼 시스템을 이용한 자율주행을 위한 실시간 GPS 위치 데이터 보정)

  • 정준익;노도환
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.41 no.6
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    • pp.187-193
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    • 2004
  • In this paper, we proposed the GPS position data correction method for autonomous land navigation using vanishing point property and a monocular vision system. Simulations are carried out over driving distances of approximately 60 km on the basis of realistic road data. On a straight road, the proposed method reduces GPS position error by at least 63% within 0.5 m. However, the average accuracy of the method is not presented, because it is difficult to estimate it on other than a straight road in variable conditions.

Sensor Fusion of GPS/INS/Baroaltimeter Using Wavelet Analysis (GPS/INS/기압고도계의 웨이블릿 센서융합 기법)

  • Kim, Seong-Pil;Kim, Eung-Tai;Seong, Kie-Jeong
    • Journal of Institute of Control, Robotics and Systems
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    • v.14 no.12
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    • pp.1232-1237
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    • 2008
  • This paper introduces an application of wavelet analysis to the sensor fusion of GPS/INS/baroaltimeter. Using wavelet analysis the baro-inertial altitude is decomposed into the low frequency content and the high frequency content. The high frequency components, 'details', represent the perturbed altitude change from the long time trend. GPS altitude is also broken down by a wavelet decomposition. The low frequency components, 'approximations', of the decomposed signal address the long-term trend of altitude. It is proposed that the final altitude be determined as the sum of both the details of the baro-inertial altitude and the approximations of GPS altitude. Then the final altitude exclude long-term baro-inertial errors and short-term GPS errors. Finally, it is shown from the test results that the proposed method produces continuous and sensitive altitude successfully.

Performance Testing of Integrated Strapdwon INS and GPS

  • Lee, Sang-Joog;Yoo, Chang-Sun;Shim, Yo-Han;Kim, Jong-Chul
    • International Journal of Aeronautical and Space Sciences
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    • v.2 no.1
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    • pp.67-77
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    • 2001
  • In recent navigation system, the profitable solution is to integrate the GPS and Stapdwon INS (SDINS) system and its integration allows compensation for shortcomings of each system. This paper describes the hardware preparation and presents the test results obtained from the automobile test of the developed system. The automobile tests was conducted with two kinds of inertial sensors and GPS receivers : short range and middle range test, to verify and evaluate the performance of the integrated navigation system. The reference of position is given by the Differential GPS(DGPS) which has cm-level accuracy to compare the accuracy of system. Kalman filtering is used for integrating GPS and SDINS and this filter effectively allows the long-term stability of GPS to correct and decrease the time deviation error of SDINS.

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