Determination of ground displacement of 25 April 2015 Nepal earthquake by GNSS precise point positioning

Abstract To obtain the coordinates by means of precise point positioning (PPP) technique we need to use the undifferenced GPS pseudocode and carrier phase observations but to obtain the “precise” positioning we need precise orbit and clock data too. This products and other information for obtaining the results by using PPP technique on a centimeter level accuracy can be downloaded from different locations, but the most reliable satellite ephemerides and clock correction are available from International GNSS Service (IGS). In the PPP analysis we determined the parameters such as the receiver clock error, ionospheric delays code biases, code multipath and the total neutral atmosphere delay of the observations. For the determination of the permanent station coordinates, using the PPP technique, we used precise orbit and clock solutions to enable absolute positioning of a single receiver. In this article we present the results obtained by using the PPP technique on the permanent station Oradea, from which we can conclude that the PPP technique can be used for different GNSS application.

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Determination of tectonic velocities of some continuously operating reference stations (CORS) in Vietnam 2016-2018 by using precise point positioning

Vietnam Journal of Earth Sciences ◽

10.15625/0866-7187/15571 ◽

2020 ◽

Vol 43 (1) ◽

pp. 1-12

Author(s):

Nguyen Ngoc Lau ◽

Richard Coleman ◽

Ha Minh Hoa

Keyword(s):

Precise Point Positioning ◽

Accurate Determination ◽

Three Dimensional ◽

Plate Motion ◽

Tectonic Plate ◽

North East ◽

The North ◽

Positioning Technique ◽

Point Positioning

Determining the speed of tectonic plate displacement helps us to better understand tectonic activities of the area, and is a prerequisite to help forecast earthquakes. The determination of tectonic plate displacement by GNSS technology in Vietnam has been conducted since the 2000s, mainly using the relative positioning technique. The increasing accuracy of precise point positioning technique, and the number of CORS in Vietnam, will facilitate the accurate determination of tectonic velocities. Based on the GNSS data of some CORSs in Vietnam from 2016-2018, we have determined accurately their three-dimensional coordinates using a precise point positioning technique. After modeling periodic variations on the time series, we calculated the tectonic movement rate of 7 Vietnamese stations and 3 other stations in the region. Through analysis and comparison with other geology/plate motion models and GPS results, we conclude that this result is reliable. The velocity of tectonic motion in the North, East and Up components of Ha Noi, Da Nang and Ho Chi Minh City are respectively (-13.1, +32.8, -1.3), (-9.9, +31.0, +2.6) and (-10.3, +26.9, +2.7) mm/year.

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A Comparative Study of Precise Point Positioning (PPP) Accuracy Using Online Services

Reports on Geodesy and Geoinformatics ◽

10.1515/rgg-2016-0025 ◽

2016 ◽

Vol 102 (1) ◽

pp. 15-31 ◽

Cited By ~ 5

Author(s):

Marcin Malinowski ◽

Janusz Kwiecień

Keyword(s):

Precise Point Positioning ◽

Reference Station ◽

Horizontal Distance ◽

Relative Height ◽

Height Difference ◽

Spatial Reference ◽

Point Positioning ◽

The Difference ◽

The Impact

Abstract Precise Point Positioning (PPP) is a technique used to determine the position of receiver antenna without communication with the reference station. It may be an alternative solution to differential measurements, where maintaining a connection with a single RTK station or a regional network of reference stations RTN is necessary. This situation is especially common in areas with poorly developed infrastructure of ground stations. A lot of research conducted so far on the use of the PPP technique has been concerned about the development of entire day observation sessions. However, this paper presents the results of a comparative analysis of accuracy of absolute determination of position from observations which last between 1 to 7 hours with the use of four permanent services which execute calculations with PPP technique such as: Automatic Precise Positioning Service (APPS), Canadian Spatial Reference System Precise Point Positioning (CSRS-PPP), GNSS Analysis and Positioning Software (GAPS) and magicPPP - Precise Point Positioning Solution (magicGNSS). On the basis of acquired results of measurements, it can be concluded that at least two-hour long measurements allow acquiring an absolute position with an accuracy of 2-4 cm. An evaluation of the impact on the accuracy of simultaneous positioning of three points test network on the change of the horizontal distance and the relative height difference between measured triangle vertices was also conducted. Distances and relative height differences between points of the triangular test network measured with a laser station Leica TDRA6000 were adopted as references. The analyses of results show that at least two hours long measurement sessions can be used to determine the horizontal distance or the difference in height with an accuracy of 1-2 cm. Rapid products employed in calculations conducted with PPP technique reached the accuracy of determining coordinates on a close level as in elaborations which employ Final products.

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Real-Time Orbit Determination of Korean Navigation Satellite System based on Multi-GNSS Precise Point Positioning

E3S Web of Conferences ◽

10.1051/e3sconf/20199403008 ◽

2019 ◽

Vol 94 ◽

pp. 03008 ◽

Cited By ~ 1

Author(s):

Gimin Kim ◽

Hyungjik Oh ◽

Chandeok Park ◽

Seungmo Seo

Keyword(s):

Real Time ◽

Orbit Determination ◽

Precise Point Positioning ◽

Satellite System ◽

Navigation Satellite ◽

Receiver Clock ◽

Point Positioning ◽

Clock Offset ◽

Monitoring Stations

This study proposes real-time orbit/clock determination of Korean Navigation Satellite System (KNSS), which employs the kinematic precise point positioning (PPP) solutions of multiple Global Navigation Satellite System (multi-GNSS) to compensate for receiver clock oﬀset. Global visibility of KNSS satellites in terms of geometric coverage is first analyzed for the purpose of selecting optimal locations of KNSS monitoring stations among International GNSS Service (IGS) and Multi-GNSS Experiment (MGEX) network. While the receiver clock oﬀset is obtained from multi-GNSS PPP clock solutions of real observation data, KNSS measurements are simulated from the dynamically propagated KNSS reference orbit and the receiver clock oﬀset. The oﬀset and drift of satellite clock are also generated based on two-state clock model considering atomic clock noise. Real-time orbit determination results are compared with an artificially generated true or bit, wihch show 0.4m and 0.5m of 3-dimensional root-mean-square (RMS) position errors for geostationary (GEO) and ellitically-inclined-geosynchronous-orbit (EIGSO) satellites, respectively. The overall results show that the real-time precise orbit determination of KNSS should be achievable in meter level by installing KNSS-compatible multi-GNSS receivers on the IGS and/or MGEX network. The overall process can be also used to verify integrity of KNSS monitoring stations.

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Ground displacement of the 6 July 2019 Ridgecrest earthquake from the GNSS permanent stations

Vietnam Journal of Earth Sciences ◽

10.15625/0866-7187/41/4/14234 ◽

2019 ◽

Vol 41 (4) ◽

pp. 305-320

Author(s):

Nguyen Ngoc Lau ◽

Phan Trong Trinh ◽

Tran Van Phong ◽

Pham Thai Binh

Keyword(s):

Earthquake Prediction ◽

Ambiguity Resolution ◽

Precise Point Positioning ◽

Precise Determination ◽

Earthquake Epicenter ◽

Ground Displacement ◽

Affected Area ◽

Seismic Displacements ◽

Gnss Permanent Stations

The Eastern California earthquake (also known as the Ridgecrest earthquake) occurred at 03:19:53 (UTC) on the 6th of July, with a moment magnitude of 7.1. Over the region, there is an accurate network of GNSS permanent stations. Precise determination of displacements of these stations will provide important information to better understand the structure and scope of the earthquake, contributing to faster and more accurate earthquake prediction. In this paper, we used precise point positioning with ambiguity resolution to determine the co-seismic displacements of 25 GNSS stations around the epicenter for the day of the earthquake. The processing results show that the affected area being more than 100 km centered around the earthquake epicenter with the largest value being approximately 0.6 m.

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