• Title/Summary/Keyword: precise positioning

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The Comparison and Analysis of Maritime Precise Positioning using GPS Based Smartphone

  • Park, Sul Gee;Park, Sang Hyun
    • Journal of Positioning, Navigation, and Timing
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    • v.7 no.4
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    • pp.217-226
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    • 2018
  • According to the Korea Coast Guard's maritime disaster statistics (Korea Coast Guard 2017, Korean Statistical information Service 2018), an average of 2,140 marine accidents occurred every year for the past 6 years and the number of accidents is increasing every year. Among them, maritime accidents of fishing vessels are the most frequent, and recently accidents involving fishing boat and leisure vessels are rapidly increasing as well. In particular, the number of accidents involving leisure vessels increased to about one-third of the accidents of fishing vessels, and emergency rescue requests are increasing every year accordingly. However, the number of crash accidents involving users of small vessels and marine leisure activities are increasing because of the difficulties of installing navigation equipment and electronic navigation charts. Recently, the demand for precise positioning using mobile devices is increasing in the fields of maritime safety, piloting support, and coastal survey. Although various applications of smart devices provide location-based services for users, the measurement results are discontinuous when using the position coordinates of the National Marine Electronics Association (NMEA) calculated by smartphone. Recently, Google announced that they will provide GPS raw data to developers from Android 7.0 Nougat. As a result, developers have an opportunity to receive precise carrier phase and code measurements to make more accurate positioning according to the performance of Android devices. This study analyzed GPS positioning performance using Android devices, and compared and analyzed the positioning performance at sea with high-performance GPS receivers.

Accuracy Analysis of Precise Point Positioning Using Predicted GPS Satellite Orbits (GPS 예측궤도력을 이용한 정밀단독측위 정확도 분석)

  • Ha, Ji-Hyun;Heo, Moon-Beom;Nam, Gi-Wook
    • Journal of Advanced Navigation Technology
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    • v.16 no.5
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    • pp.752-759
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    • 2012
  • In this paper, near-real-time positioning accuracies of precise point positioning technique were analyzed using IGS predicted orbits. As a result, we could get the mean errors of 1~1.6 cm, standard deviation of 1~1.3cm from one year of GPS data. This results were similar level to positioning accuracy using the IGS rapid orbits. Positioning errors of >10cm showed 44% of observed days of orbital anomalies. When the orbital anomalies of the predicted orbits were shown, maximum error was 1.7 km, and maximum of mean errors was 308 m. From this study, we conclude that check and consideration were necessary before using the IGS predicted orbits.

Development and Positioning Accuracy Assessment of Precise Point Positioning Algorithms Based on GLONASS Code-Pseudorange Measurements

  • Kim, Mi-So;Park, Kwan-Dong;Won, Jihye
    • Journal of Positioning, Navigation, and Timing
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    • v.3 no.4
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    • pp.155-161
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    • 2014
  • The purpose of this study is to develop precise point positioning (PPP) algorithms based on GLONASS code-pseudorange, verify their performance and present their utility. As the basic correction models of PPP, we applied Inter Frequency Bias (IFB), relativistic effect, satellite antenna phase center offset, and satellite orbit and satellite clock errors, ionospheric errors, and tropospheric errors that must be provided on a real-time basis. The satellite orbit and satellite clock errors provided by Information-Analytical Centre (IAC) are interpolated at each observation epoch by applying the Lagrange polynomial method and linear interpolation method. We applied Global Ionosphere Maps (GIM) provided by International GNSS Service (IGS) for ionospheric errors, and increased the positioning accuracy by applying the true value calculated with GIPSY for tropospheric errors. As a result of testing the developed GLONASS PPP algorithms for four days, the horizontal error was approximately 1.4 ~ 1.5 m and the vertical error was approximately 2.5 ~ 2.8 m, showing that the accuracy is similar to that of GPS PPP.

The Coordinates Computation of the GPS Base Station by Precise Point Positioning (정밀절대측위(PPP)기법에 의한 GPS 기준점 좌표의 산정)

  • 이용창
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.17 no.2
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    • pp.145-152
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    • 1999
  • JPL(Jet Propulsion Laboratory) has been routinely produced the precise GPS ephemeris and clock's correction parameter using data collected from globally distributed permanent GPS tracking stations, and has been offering the automated GPS data analysis(Precise Point Positioning: PPP) service by using them. In this study, after investigating the potential capacity of JPL's PPP service, the coordinates computation of the GPS base station by this service were investigated. For this, the dual frequency P codes data of 24 hours were observed from continuously operating four reference stations in USA. sent to the JPL's main computer through E-mail and/or ftp, and then were processed by Gipsy/Oasis-II (GOA-II) software with the precise GPS transmitter parameters. Centimeter-level positioning results were available to obtain in X, Y, Z geocentric rectangular coordinate system.

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DEVELOPMENT OF REAL-TIME PRECISE POSITIONING ALGORITHM USING GPS L1 CARRIER PHASE DATA (GPS L1 반송파 위상을 이용한 실시각 정밀측위 알고리즘 구현)

  • 조정호;최병규;박종욱;박관동;임형철;박필호
    • Journal of Astronomy and Space Sciences
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    • v.19 no.4
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    • pp.377-384
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    • 2002
  • We have developed Real-time Phase DAta processor(RPDAP) for GPS L1 carrie. And also, we tested the RPDAP's positioning accuracy compared with results of real time kinematic(RTK) positioning. While quality of the conventional L1 RTK positioning highly depend on receiving condition, the RPDAP can gives more stable positioning result because of different set of common GPS satellites, which searched by elevation mask angle and signal strength. In this paper, we demonstrated characteristics of the RPDAP compared with the L1 RTK technique. And we discussed several improvement ways to apply the RPDAP to precise real-time positioning using low-cost GPS receiver. With correcting the discussed weak points in new future, the RPDAP will be used in the field of precise real-time application, such as precise car navigation and precise personal location services.

Development of Precise Point Positioning Solution for Detection of Earthquake and Crustal Movement (지진 및 지각변동 감지를 위한 정밀절대측위 솔루션 개발)

  • Park, Joon-Kyu;Kim, Min-Gyu
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.9
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    • pp.4587-4592
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    • 2013
  • GPS is recognized the essential method to obtain the best result in the sphere of earth science that is setting of International Reference Frame, decision of the rotation coefficient about the earth rotation axis, detection of the crustal deformation, and observation of the diastrophism by high precision positioning except for navigation, geodetic survey and mapping. Therefore, in this study, it was attempted to build an expert service that enables non-experts to use high-precision GPS data processing. As a result, an Precise Point Positioning Solution that can maximize user convenience simply by entering the minimum required information for GPS data processing was developed, and the result of Precise Point Positioning Solution using GPS data provided by National Geographic Information Institute was compared with result of ITRF.

Precise open-loop positioning using LPM with error correction

  • Furuhashi, Hideo;Shingu, Hiroyasu;Hayashi, Niichi;Watanabe, Shigeo;Sumi, Tetsuo;Uchida, Yoshiyuki
    • 제어로봇시스템학회:학술대회논문집
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    • 1995.10a
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    • pp.211-214
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    • 1995
  • A precise open-loop positioning system using linear pulse motor has been developed. The system is operated in a microstepping mode by controlling the electric current. One step of 508 .mu.m (tooth pitch of the linear pulse motor) is divided into 508 micro-steps equally. The displacement is measured with a system using a Fiezeau-type interferometer. Periodical positioning error with a period of the tooth pitch was observed in this system. Therefore, the position is corrected using the error. The error is stored into computer in advance, and the microstep current is corrected on basis of the stored data. Although the positioning error of the system without the correction was .+-.4.5 .mu.m, that with the correction was decreased to .+-.1.0 .mu.m.

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A Precise Relative Positioning Method Based on Time-Differenced Carrier Phase Measurements from Low-Cost GNSS Receiver (저비용 GNSS 수신기를 이용한 반송파 위상 시각간 차분 측정치 기반의 정밀 상대위치 결정 기법)

  • Park, Kwi-Woo;Lee, DongSun;Park, Chansik
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.40 no.9
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    • pp.1846-1855
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    • 2015
  • In this paper, a precise relative positioning with TD(time differenced) carrier phase measurements from a low-cost GNSS(Global Navigation Satellite System) receiver is proposed and analysed. The proposed method is using carrier phase measurement from a single GNSS receiver that reference receiver is not required and stand alone positioning is possible. TD operation removes the troublesome integer ambiguity resolution problem, and if the time interval is short, other error, such as, ionospheric, tropospheric delay and ephemeris error are effectively eliminated. The error analysis of the proposed method shows that a precise and positioning with carrier phase is possible. The implemented system is evaluated using a real car experiments. The results show that the horizontal positioning error was less than 3m during 10 minutes experiments, which is 4 times more precise than the results of normal code based absolute positioning.

Precise position control of piezoelectric actuators considering input frequency variance (입력주파수 변화특성을 고려한 압전구동기의 정밀위치제어)

  • 송재욱;김호상;이효정
    • 제어로봇시스템학회:학술대회논문집
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    • 1996.10b
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    • pp.1052-1055
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    • 1996
  • Piezoelectric actuator is widely used in precision positioning applications due to its excellent positioning resolution. However, serious hysteresis nonlinearity of the actuator deteriorates its precise positioning capability. Evenworse, its hysteresis nonlinearity changes as the actuator input frequency varies. In this study, a simple feedforward scheme is proposed and tested through experiments for precision position control when the variance of the system input frequency is significant.

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