• Title/Summary/Keyword: Precise GPS Positioning

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Study on Applying GPS Positioning Technique to Cannon Laying (GPS 측위기술의 포 방열 적용 연구)

  • 조정호;박종욱;박필호;임형철;최만수;권영철
    • Journal of the Korea Institute of Military Science and Technology
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    • v.4 no.2
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    • pp.52-59
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    • 2001
  • In this paper, we have proposed a capability of applying Global Positioning System(GPS) to cannon laying. High precision GPS positioning can be used for measuring precise positions and angles. Therefore, we have tested on applying GPS positioning technique to measurement of positions and angles, which related to cannon laying. First of all, we have determined a GPS reference position using various positioning methods. Then we have carried out several tests that are process of taking corner angles between neighboring two vectors. Each vector can be calculated by post/real time positioning of two GPS antennas placed on the both ends of the howitzer. The Comer Angles from Post processing(CAP) are compared with the other Corner Angles from Real time positioning(CAR). As the results, we have an agreement between CAP and CAR within 0.25 mil average, 0.29 mil standard deviation. Finally, we have discussed about the capabilities and problems in artillery arrangement using GPS.

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Precise Orbit Determination of GRACE-A Satellite with Kinematic GPS PPP

  • Choi, Byung-Kyu;Roh, Kyoung-Min;Yoo, Sung-Moon;Jo, Jung-Hyun;Lee, Sang-Jeong
    • Journal of Positioning, Navigation, and Timing
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    • v.1 no.1
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    • pp.59-64
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    • 2012
  • Precise Point Positioning (PPP) has been widely used in navigation and orbit determination applications as we can obtain precise Global Positioning System (GPS) satellite orbit and clock products. Kinematic PPP, which is based on the GPS measurements only from the spaceborne GPS receiver, has some advantages for a simple precise orbit determination (POD). In this study, we developed kinematic PPP technique to estimate the orbits of GRACE-A satellite. The comparison of the mean position between the JPL's orbit product and our results showed the orbit differences 0.18 cm, 0.54 cm, and 0.98 cm in the Radial, in Along-track, and Cross-track direction respectively. In addition, we obtained the root mean square (rms) values of 4.06 cm, 3.90 cm, and 3.23 cm in the satellite coordinate components relative to the known coordinates.

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.

GPS Satellite Orbit Prediction Based on Unscented Kalman Filter

  • Zheng, Zuoya;Chen, Yongqi;Xiushan, Lu;Zhixing, Du
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.1
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    • pp.191-196
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    • 2006
  • In GPS Positioning, the error of satellite orbit will affect user's position accuracy directly, it is important to determine the satellite orbit precise. The real-time orbit is needed in kinematic GPS positioning, the precise GPS orbit from IGS would be delayed long time, so orbit prediction is key to real-time kinematic positioning. We analyze the GPS predicted ephemeris, on the base of comparison of EKF and UKF, a new orbit prediction method is put forward based on UKF in this paper, the result shows that UKF improves the orbit predicted precision and stability. It offers a new method for others satellites orbit determination as Galileo, and so on.

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Precise Surveying of Ship Launching Distance Using RTK-GPS (RTK-GPS를 이용한 선박진수거리 정밀측량)

  • 장용구;송석진;강인준
    • Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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    • 2004.03a
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    • pp.455-461
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    • 2004
  • Now, GPS survey is used on equipment from leisure to precise geodetic survey and nation admits the result of GPS survey. When surveyors perform precise GPS survey, they use post processing method but they greatly use real time processing method to consider field status. Especially, when surveyors measure the result of moving target, they use real time GPS survey to the best method. For this study, the author precisely surveyed distance of ship launching from shipyard on real time using real time precise GPS method. In this paper, the author compares and examines the accuracy of first real time precise GPS survey method nationally and the capability on use. And the author performed real time precise GPS survey in NOKBONG and 21C shipyard positioning at GEOJEDO.

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Development of Precise Point Positioning Method Using Global Positioning System Measurements

  • Choi, Byung-Kyu;Back, Jeong-Ho;Cho, Sung-Ki;Park, Jong-Uk;Park, Pil-Ho
    • Journal of Astronomy and Space Sciences
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    • v.28 no.3
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    • pp.217-223
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    • 2011
  • Precise point positioning (PPP) is increasingly used in several parts such as monitoring of crustal movement and maintaining an international terrestrial reference frame using global positioning system (GPS) measurements. An accuracy of PPP data processing has been increased due to the use of the more precise satellite orbit/clock products. In this study we developed PPP algorithm that utilizes data collected by a GPS receiver. The measurement error modelling including the tropospheric error and the tidal model in data processing was considered to improve the positioning accuracy. The extended Kalman filter has been also employed to estimate the state parameters such as positioning information and float ambiguities. For the verification, we compared our results to other of International GNSS Service analysis center. As a result, the mean errors of the estimated position on the East-West, North-South and Up-Down direction for the five days were 0.9 cm, 0.32 cm, and 1.14 cm in 95% confidence level.

Design of Multi-Band GPS/KPS RTK Simulator (다중대역 GPS/KPS 통합 측위 시뮬레이터의 설계)

  • Young-Ho Jung;Taek Geun Lee;Kwangjae Lim;Hyoungsoo Lim;Hyung Keun Lee
    • Journal of Positioning, Navigation, and Timing
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    • v.13 no.3
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    • pp.341-353
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    • 2024
  • This paper presents the design results of a Multi-band Global Positioning System (GPS)/Korean Positioning System (KPS) Real-Time Kinematics (RTK) precise positioning simulator and evaluate its functionalities. The designed simulator consists of a trajectory generation module, a Radio Frequency (RF) signal generation module, a RF signal reception module, a coarse positioning module, a precise positioning module, and an error statistics reporting module. Simulations in realistic scenarios confirm that the proposed baseband simulator works appropriately. The developed simulator can adjust the type, number, band, and Pseudo Random Noise (PRN) code type of the satellite constellation in various ways, and the practical positioning performance can be tested. It can also reflect the channel influence at the actual RF stage and the influence during the initial synchronization and tracking process. Considering such advantages, the proposed simulator would be useful in future researches and developments related to KPS.

Development and Positioning Accuracy Assessment of Precise Point Positioning Algorithms based on GPS Code-Pseudorange Measurements (GPS 코드의사거리 기반 정밀단독측위(PPP) 알고리즘 개발 및 측위 정확도 평가)

  • Park, Kwan Dong;Kim, Ji Hye;Won, Ji Hye;Kim, Du Sik
    • Journal of Korean Society for Geospatial Information Science
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    • v.22 no.1
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    • pp.47-54
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    • 2014
  • Precise Point Positioning (PPP) algorithms using GPS code pseudo-range measurements were developed and their accuracy was validated for the purpose of implementing them on a portable device. The group delay, relativistic effect, and satellite-antenna phase center offset models were applied as fundamental corrections for PPP. GPS satellite orbit and clock offsets were taken from the International GNSS Service official products which were interpolated using the best available algorithms. Tropospheric and ionospheric delays were obtained by applying mapping functions to the outputs from scientific GPS data processing software and Global Ionosphere Maps, respectively. When the developed algorithms were tested for four days of data, the horizontal and vertical positioning accuracies were 0.8-1.6 and 1.6-2.2 meters, respectively. This level of performance is comparable to that of Differential GPS, and further improvements and fine-tuning of this suite of PPP algorithms and its implementation at a portable device should be utilized in a variety of surveying and Location-Based Service applications.

Accuracy Evaluation of IGS-RTS Corrections to Stand-Alone Positioning Based on GPS Code-Pseudorange Measurements

  • Kang, Min-Wook;Won, Jihye;Kim, Mi-So;Park, Kwan-Dong
    • Journal of Positioning, Navigation, and Timing
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    • v.5 no.2
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    • pp.59-66
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    • 2016
  • The International GNSS Service (IGS) provides the IGS-Real Time Service (IGS-RTS) corrections that can be used in stand-alone positioning in real time. In this study, the positioning accuracy before and after the application of the corrections to broadcast ephemeris by applying the IGS-RTS corrections at code pseudo-range based stand-alone positioning was compared with positioning result using precise ephemeris. The analysis result on IGS-RTS corrections showed that orbit error and clock error were 0.05 m and 0.5 ns compared to precise ephemeris and accuracy improved by about 8.5% compared to the broadcast ephemeris-applied result when the IGS-RTS was applied to positioning. Furthermore, regionally dispersed five observatories were selected to analyze the effect of external environments on positioning accuracy and positioning errors according to location and time were compared as well as the number of visible satellites and position dilution of precision by observatory were analyzed to verify a correlation with positioning error.

Long Baseline GPS RTK with Estimating Tropospheric Delays

  • Choi, Byung-Kyu;Roh, Kyoung-Min;Lee, Sang Jeong
    • Journal of Positioning, Navigation, and Timing
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    • v.3 no.3
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    • pp.123-129
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    • 2014
  • The real-time kinematic (RTK) is one of precise positioning methods using Global Positioning System (GPS) data. In the long baseline GPS RTK, the ionospheric and tropospheric delays are critical factors for the positioning accuracy. In this paper we present RTK algorithms for long baselines more than 100 km with estimating tropospheric delays. The state vector is estimated by the extended Kalman filter. We show the experimental results of GPS RTK for various baselines (162.10, 393.37, 582.29, and 1283.57 km) by using the Korea Astronomy and Space Science Institute GPS data and one International GNSS Service (IGS) reference station located in Japan. As a result, we present that long baseline GPS RTK can provide the accurate positioning for users less than few centimeters.