• Title, Summary, Keyword: GPS

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Analysis of the GPS Signal Generator for the Live GPS Signal Synchronization (Live GPS L1과 동기된 항법신호 생성 분석)

  • Kim, Taehee;Sin, Cheonsig;Kim, Jaehoon
    • Journal of Satellite, Information and Communications
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    • v.10 no.1
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    • pp.71-76
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    • 2015
  • In this paper, we developed the hardware GPS signal generator for generating a satellite navigation signal synchronized with Live GPS signal signals and analyzed the performance of signal genterator thorough the experiment For a hardware implementation of the GPS navigation signal synchronous generator, the GPS module may receive a GPS signal in order to generate the same signal as the operation that is transmitted from the current GPS satellite and the synchronized time information and the GPS satellites using the Novatel Inc. OEMStar.In. For generating the GPS synchronization signal, the GPS navigation signal generator was adjusted to a reference clock using the GPS clock synchronous information provided by the GPS receiving module and GPS signals also generated in consideration of the delay of the internal hardware of the generator. In this paper, we analyzed the effect of the receiver via the signal switching between Live GPS signal and generates a signal to measure the performance of the GPS navigation synchronization signal generator. It was confirmed that by the seamless operation of the signal even the moment that the switching of the generated signal from Live GPS signal has occurred through experimentation.

An Analysis on GPS Jammer Operational Range Against GPS Receiver in Sea Environment (해상환경의 GPS 수신기에 대한 GPS 재머의 운용반경 분석)

  • Lee, Young-Joong;Park, Joo-Rae;Kim, Jong-Kyu
    • Journal of the Korea Institute of Military Science and Technology
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    • v.14 no.2
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    • pp.232-237
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    • 2011
  • This paper analyzed the J/S of the GPS receiver in sea environment from GPS satellite and GPS jammer. Through the analysis, the operational range and effective radiation power of the GPS jammer could be estimated. In the case of the jammer effective radiation power is higher than the specific value, jammer height mainly resolves the jammer operational range.

Developement of GPS Data Quality Control Program (GPS 데이터 품질관리 프로그램의 개발)

  • Yun Hong-Sic;Lee Dong-Ha;Lee Young-Kyun;Cho Jae-Myung
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.24 no.1
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    • pp.9-18
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    • 2006
  • This paper describes a new program called GPS_QC needed to check the quality of GPS observations before post-processing so that the surveyors can be improved the precision of GPS data analysis. The GPS_QC was designed to calculate the quality control (QC) parameters such as data gaps, cycle slips, low elevation angle, inonspheric delay, multi-path effects and DOP etc, within the period of GPS observation. It can be used to read and calculate the QC parameters from RINEX files. This program gives users brief statistics, time series plots and graphs of QC parameters. The GPS_QC can simply be performed the quality checking of GPS data that was difficult for surveyors in the field. It is expected that we can be improved the precision of positioning and solved the time consuming problem of GPS observation.

Analysis of Influences due to Navigation Message Error of GPS Signals on Receiver (GPS 항법메시지 이상이 수신기에 미치는 영향 분석)

  • Kang, Hee-Won;Cho, Deuk-Jae;Park, Sang-Hyun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.14 no.10
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    • pp.2223-2229
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    • 2010
  • The integrity monitoring of anomalous GPS signal have been researched because of the degradation of GPS satellite performance. It is known that anomalous GPS signal can occur by failure of GPS satellite, sudden increase of ionosphere delay error, SA, wrong modeling for navigation parameters from control segment, and an electromagnetic wave interference, etc. In case of GPS anomaly by satellites can arise from carrier frequency, code and navigation message. In this paper, the scenarios with navigation message errors were made by using GPS simulator, and the influences of GPS navigation message error to receiver were analysed. The anomalies of preamble, bits related TOW count message, subframe ID in HOW, bits related satellite healthy, and the other navigation message errors were described and simulated. Also, the number of satellites, DOP and pseudorange are analyzed to know how the anomalous signal can affect on GPS receiver.

Performance Analysis of GPS Antenna for KSLV-I under Hot Temperature Environment (고온 환경에서 KSLV-I 발사체용 GPS 안테나의 성능 분석)

  • Moon, Ji-Hyeon;Kwon, Byung-Moon;Choi, Hyung-Don;Jung, Ho-Rac
    • Aerospace Engineering and Technology
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    • v.6 no.1
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    • pp.157-164
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    • 2007
  • For a GPS antenna to normally receive GPS satellite signals during full flight mission of a satellite launch vehicle, it should be installed on skin of the vehicle. The surface of a launch vehicle is drastically heated up due to aerodynamic heating effect during flight, so that the GPS antenna mounted on surface of the launch vehicle is directly exposed to extremely hot temperature environment. Hot temperature test specification of the GPS antenna, therefore, is severer than inner components. This paper describes that procedures and results of performance analysis of the GPS antenna for KSLV-I under hot temperature environment. The GPS antenna was not deformed physically and inner LNA(Low Noise Amplifier) operated normally without performance degradation.

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Outdoor Localization of a Mobile Robot Using Weighted GPS Data and Map Information (가중화된 GPS 정보와 지도정보를 활용한 실외 이동로봇의 위치추정)

  • Bae, Ji-Hun;Song, Jae-Bok;Choi, Ji-Hoon
    • The Journal of Korea Robotics Society
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    • v.6 no.3
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    • pp.292-300
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    • 2011
  • Global positioning system (GPS) is widely used to measure the position of a vehicle. However, the accuracy of the GPS can be severely affected by surrounding environmental conditions. To deal with this problem, the GPS and odometry data can be combined using an extended Kalman filter. For stable navigation of an outdoor mobile robot using the GPS, this paper proposes two methods to evaluate the reliability of the GPS data. The first method is to calculate the standard deviation of the GPS data and reflect it to deal with the uncertainty of the GPS data. The second method is to match the GPS data to the traversability map which can be obtained by classifying outdoor terrain data. By matching of the GPS data with the traversability map, we can determine whether to use the GPS data or not. The experimental results show that the proposed methods can enhance the performance of the GPS-based outdoor localization.

Fused Navigation of Unmanned Surface Vehicle and Detection of GPS Abnormality (무인 수상정의 융합 항법 및 GPS 이상 검출)

  • Ko, Nak Yong;Jeong, Seokki
    • Journal of Institute of Control, Robotics and Systems
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    • v.22 no.9
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    • pp.723-732
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    • 2016
  • This paper proposes an approach to fused navigation of an unmanned surface vehicle(USV) and to detection of the outlier or interference of global positioning system(GPS). The method fuses available sensor measurements through extended Kalman filter(EKF) to find the location and attitude of the USV. The method uses error covariance of EKF for detection of GPS outlier or interference. When outlier or interference of the GPS is detected, the method excludes GPS data from navigation process. The measurements to be fused for the navigation are GPS, acceleration, angular rate, magnetic field, linear velocity, range and bearing to acoustic beacons. The method is tested through simulated data and measurement data produced through ground navigation. The results show that the method detects GPS outlier or interference as well as the GPS recovery, which frees navigation from the problem of GPS abnormality.

Study on SDINS/GPS Kalman Filter using GPS carrier phase rate measurements (GPS 반송파 위상변화율을 이용한 SDINS/GPS 복합항법 필터 구성)

  • Park, Jun-Gu
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.34 no.11
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    • pp.42-46
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    • 2006
  • As an application of SDINS/GPS integration for its synergistic results, the SDINS alignments utilizing GPS carrier phase rate measurements. A measurement model of GPS carrier phase rate is derived in order to be used with SDINS alignment process. For in-flight alignment, the performance of the suggested SDINS/GPS integration method is analyzed using the covariance analysis and its results are confirmed by those of van test. Consequently, it is shown that all states of the SDINS integrated system by utilizing GPS carrier phase rate measurements can be estimated more efficiently than a general SDINS/GPS during in-flight alignment.

The Verification of Precision of Single RTK-GPS using CORS (CORS를 이용한 Single RTK-GPS 정확도 검증)

  • Park, Un-Yong;Lee, Dong-Rak;Lee, In-Su;Bae, Kyoung-Ho
    • Journal of Korean Society for Geospatial Information System
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    • v.12 no.2
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    • pp.29-35
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    • 2004
  • The plenty of availability and high precision of GPS CORS is the reason why it become important more and more in the fields of surveying widely. In this study, I extracted the arbitrary point's coordinate which is using GPS CORS data, now served in RINEX FORMAT via Inter-Net, with observation network of the existing triangulation and GPS CORS data. Then, with this arbitrary point as reference station RTK GPS was performed. And I will study VRS-GPS concept which reduces the time and cost in the fields of surveying.

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Improvement of GPS Relative Positioning Accuracy by Using Crustal Deformation Model in the Korean Peninsula (GPS상대측위 정확도 향상을 위한 한반도 지각변동모델 개발)

  • Cho, Jae-Myoung;Yun, Hong-Sik;Lee, Mi-Ran
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.29 no.3
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    • pp.237-247
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    • 2011
  • As of 2011, 72 Permanent GPS Stations are installed to control DGPS reference points by the National Geographic Information Institute in South Korea. As the center of the Earth's mass continues to move, the coordinates of the permanent GPS stations become inconsistent over time. Thus, a reference frame using a set of coordinates and their velocities of a global network of stations at a specific period has been used to solve the inconsistency. However, the relative movement of the permanent GPS stations can lower the accuracy of GPS relative positioning. In this research, we first analyzed the data collected daily during the past 30 months at the 40 permanent GPS stations within South Korea and the 5 IGS permanent GPS stations around the Korean Peninsula using a global network adjustment. We then calculated the absolute and relative amount of movement of the GPS permanent stations. We also identified the optimum renewal period of the permanent GPS stations considering the accuracy of relative GPS surveying. Finally, we developed a Korean a Korean crustal movement model that can be used to improvement of accuracy.