• Title/Summary/Keyword: GPS

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GPS/INS AT(Aerial Triangulation) Evaluation According to GPS Processing Time (GPS 위성신호의 처리시간에 따른 GPS/INS 사진기준점측량의 정확도)

  • Lee Seung-Huhn;Wie Gwang-Jae;Kim Seung-Young;Lee Jae-Won
    • Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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    • 2006.04a
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    • pp.151-158
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    • 2006
  • As GPS 'selective availability' was turned off in 2000, GPS related fields and markets are explosively extended. In mapping area, GPS/INS aided photogrammetry proved it is much cost and time effective method keeping enough accuracy as compared with traditional photogrammetry works. The advantage of GPS/INS integration is interdependence. Even if GPS signal was blocked in some time, the position accuracy is not affected. In this study, various GPS signal time gap was used in GPS/INS AT process. Field surveyed ground points were used in accuracy check with GPS/INS AT check points. And the result showed enough accuracy of photogrammetry work rule of NGII. y.

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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.

The Accuracy Analysis of Parcel Surveying by RTK-GPS and RTK-GPS/GLONASS (RTK-GPS와 RTK-GPS/GLONASS에 의한 일필지 측랑의 정확도 분석)

  • Hong, Sung-Eon
    • Spatial Information Research
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    • v.14 no.2 s.37
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    • pp.211-221
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    • 2006
  • GLONASS(Global NAvigation Satellite System) using the satellite information on 19,100km altitude supplies the location information similar method with GPS. Therefore, many researches study in combination GPS and GLONASS. This research compares with deciding coordination of one unit parcel using RTK-GPS and RTK-GPS/CLONASS. Then we examine the possibility of RTK-GPS/GLONASS for determining parcel coordinate.

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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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Integrated Management of Digital Topographic Map and Digital Nautical Chart Using Analysis of Control Points in Precise DGPS Surveying (정밀 DGPS측량의 기준점 분석에 따른 수치지형도와 수치해도의 통합관리)

  • Jang Yong-Gu;Kim Sang-Seok
    • Journal of Navigation and Port Research
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    • v.29 no.3 s.99
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    • pp.269-274
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    • 2005
  • Geodetic surveying using precise GPS equipment are used without analysis with a statistical verification of GPS observed value and it was preformed by necessity to integration projection of digital topographic map and nautical Chart for integration geographic information system construction. The purpose of this study proposes method that improve accuracy of GPS observed value and direction that integrally manage digital topographic map and electronic nautical chart in analyzing the boundary line error between digital topographic map and nautical Chart. For improvement of the precision of GPS observed value, the author studied precision-analysis of GPS observed value by geometric strength and variance factor in 3 control points used in GPS network adjustment. And like this, produce EDM measurement using this GPS observation results and compare the whole boundary point error when set digital topographic map and nautical chart by these boundary.

A New Multi-Beam MVDR Technique for Removing Interference Signals in Array Antenna Based GPS Receivers (GPS 수신기에서 간섭신호 제거를 위한 배열 안테나 기반 다중 빔 MVDR 기법)

  • Jeong, Eui-Rim;Won, Hyun-Hee;Yang, Gi-Jung;Ahn, Byoung-Sun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.21 no.3
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    • pp.491-498
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    • 2017
  • GPS (global positioning system) is a popular system that provides location information by measuring arrival time difference at the receiver between several GPS satellite signals. GPS is widely used in commercial area as well as military systems. Reliable GPS signal reception is more important in the military applications such as guided missiles. However, since the carrier frequencies of the GPS signals are well known and the received power is extremely low, the GPS systems are vulnerable to intentional jamming attacks. To remove jammers while maintaining GPS signals at the received signals, a popular technique is an adaptive beam steering method based on array antenna. Among adaptive beam steering techniques, this paper considers MVDR (minimum variance distortionless response) algorithm, and proposes a new adaptive technique that preserves the received signals at desired directions, but removes the unknown jamming signals adaptively. The performance of the proposed method is verified through computer simulation.

Van Test for GAK NM (GPS Adapter Kit Navigation Module) Using High Performance INS (고정밀 INS를 이용한 GAK(GPS Adapter Kit) 항법 모듈의 차량 시험)

  • Oh, Sang-Heon;Son, Seok-Bo;Kwon, Seung-Bok;Shin, Don-Ho;Lee, Sang-Jeong;Park, Chan-Sik;Hwang, Dong-Hwan
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.35 no.3
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    • pp.260-267
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    • 2007
  • GPS adapter kit (GAK) is a GPS/INS guided range extension system to improve the accuracy and availability of existing dumb bombs. In this paper, a van test result of GPS/INS navigation module (NM) for guided bomb with GAK has been presented. The NM consists of a commercial MEMS IMU, embedded GPS receiver and navigation computer unit (NCU). The GPS receiver of NM was designed to use multiple antennas for satellite visibility and GPS attitude determination. The real-time navigation software was designed by modularized structure to guarantee the maintainability and extensibility. In order to evaluate the performance of the NM, a van test was preformed by using a high performance INS - Honeywell H-726 MAPS(Modular Azimuth Position System).The van test results show that the GAK NM with GPS attitude measurement gives better navigation performance than a conventional GPS/INS integration and good coasting capabilities under jamming environment.

Accuracy Analysis of Positioning Supplementary Control Point with the RTK-GPS and RTK-GPS/GLONASS (RTK-GPS와 RTK-GPS/GLONASS에 의한 도근점 측위의 정확도 분석)

  • Park, Woon-Yong;Kim, Jin-Soo;Kim, Yong-Bo;Back, Ki-Suk
    • Journal of Korean Society for Geospatial Information Science
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    • v.11 no.1 s.24
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    • pp.61-69
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    • 2003
  • The study is the open area keeping a few visible satellites and the urban area covered with the high building, an electric pole were chosen for evaluation of accuracy of satellite positioning. First, suggest the validity of RTK-GPS, RTK-GPS/GLONASS and compared the accuracy with that of the classical surveying method. As a result. In urban area, in case of real time kinematic positioning when compare between the method combined by GPS/GLONASS and by GPS alone the result of GPS/GLONASS - combination more excellent. And in open ana positioning combined GPS/GLONASS was more excellent than GPS alone in both real time differential and real time kinematic. So, RTK-GPS, RTK-GPS/GLONASS contribute to the digital mapping of Basic map and the existed map necessary for the building of PBLIS to the computerization of cadastral map in the effectiveness in time and in cost and hereafter the combined GPS/TS is expected to contribute to the development of NGIS, Re-investigation of a land register, the execution drawing on site.

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Enhancement of UAV-based Spatial Positioning Using the Triangular Center Method with Multiple GPS

  • Joo, Yongjin;Ahn, Yushin
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.37 no.5
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    • pp.379-388
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    • 2019
  • Recently, a technique for acquiring spatial information data using UAV (Unmanned Aerial Vehicle) has been greatly developed. It is a very crucial issue of the GIS (Geographic Information System) mapping system that passes way point in the unmanned airframe and finally measures the accurate image and stable localization to the desired destination. Though positioning using DGPS (Differential Global Navigation System) or RTK-GPS (Real Time Kinematic-GPS) guarantee highly accurate, they are more expensive than the construction of a single positioning system using a single GPS. In the case of a low-priced single GPS system, the stability of the positioning data deteriorates. Therefore, it is necessary to supplement the uncertainty of the absolute position data of the UAV and to improve the accuracy of the current position data economically in the operating state of the UAV. The aim of this study was to present an algorithm enhancing the stability of position data in a single GPS mode of UAV with multiple GPS. First, the arrangement of multiple GPS receivers through the center of gravity of the UAV were examined. Next, MD (Mahalanobis Distance) is applied to detect instantaneous errors of GPS data in advance and eliminate outliers to increase the accuracy of previously collected multiple GPS data. Processing procedure for multiple GPS reception data by applying the center of the triangular method were presented to improve the position accuracy. Second, UAV navigation systems integrated multiple GPS through configuration of the UAV specifications were implemented. Using the unmanned airframe equipped with multiple GPS receivers, GPS data is measured with the TCM (Triangular Center Method). In addition, UAV equipped with multiple GPS were operated in study area and locational accuracy of multiple GPS of UAV with VRS (Virtual Reference Station) GNSS surveying were compared. The result showed that the error factors are compensated, and the error range are reduced, resulting in the reliability of the corrected value. In conclusion, the result in this paper is expected to realize high-precision position estimation at low cost in UAV using multiple low-cost GPS receivers.

Application and Performance Analysis of Machine Learning for GPS Jamming Detection (GPS 재밍탐지를 위한 기계학습 적용 및 성능 분석)

  • Jeong, Inhwan
    • The Journal of Korean Institute of Information Technology
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    • v.17 no.5
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    • pp.47-55
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    • 2019
  • As the damage caused by GPS jamming has been increased, researches for detecting and preventing GPS jamming is being actively studied. This paper deals with a GPS jamming detection method using multiple GPS receiving channels and three-types machine learning techniques. Proposed multiple GPS channels consist of commercial GPS receiver with no anti-jamming function, receiver with just anti-noise jamming function and receiver with anti-noise and anti-spoofing jamming function. This system enables user to identify the characteristics of the jamming signals by comparing the coordinates received at each receiver. In this paper, The five types of jamming signals with different signal characteristics were entered to the system and three kinds of machine learning methods(AB: Adaptive Boosting, SVM: Support Vector Machine, DT: Decision Tree) were applied to perform jamming detection test. The results showed that the DT technique has the best performance with a detection rate of 96.9% when the single machine learning technique was applied. And it is confirmed that DT technique is more effective for GPS jamming detection than the binary classifier techniques because it has low ambiguity and simple hardware. It was also confirmed that SVM could be used only if additional solutions to ambiguity problem are applied.