Wyniki wyszukiwania - BazTech

1

Subsidence determination in the Central Valley, California

Romero M., Berber M. M.

Reports on Geodesy and Geoinformatics

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2018

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Vol. 106

35--42

EN

Twenty four hour GNSS (Global Navigation Satellite System) data acquired monthly for 5 years from 8 CORS (Continuously Operating Reference Station) stations in Central Valley, California are processed and vertical velocities of the points are determined. To process GNSS data, online GNSS data processing service APPS (Automatic Precise Positioning Service) is used. GNSS data downloaded from NGS (National Geodetic Survey) CORS are analyzed and subsidence at these points is portrayed with graphics. It is revealed that elevation changes range from 5 mm uplift in the north to 163 mm subsidence in the southern part of the valley.

2

Dokładność wyznaczania pozycji z zastosowaniem permanentnych usług internetowych PPP (Precise Point Positioning)

Malinowski M.

Czasopismo Inżynierii Lądowej, Środowiska i Architektury / Journal of Civil Engineering, Environment and Architecture

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2017

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z. 64, nr 4/I

297--313

PL

Precyzyjne pozycjonowanie PPP to metoda wyznaczania pozycji przy pomocy samodzielnego odbiornika GNSS. Może stanowić alternatywną technikę do pomiarów różnicowych gdzie niezbędnym jest utrzymanie łączności z pojedynczą stacją RTK lub regionalną siecią stacji referencyjnych RTN. Metoda precyzyjnego pomiaru PPP może w szczególności sprawdzić się w obszarach o słabo rozwiniętej infrastrukturze stacji naziemnych. W niniejszej pracy przedstawiono wyniki analizy dokładności precyzyjnego wyznaczania pozycji na wierzchołkach trójkątnej osnowy dla obserwacji trwających od 0,5 do 6 godzin z wykorzystaniem bezpłatnych permanentnych usług internetowych realizujących obliczenia techniką PPP jak: APPS, CSRS–PPP, magicGNSS. Dla każdego punktu osnowy pomiarowej wykonano obliczenia wykorzystując obserwacje GPS i uwzględniając produkty Final. Wykonano ocenę wpływu dokładności jednoczesnego pozycjonowania trzech punktów osnowy pomiarowej na zmianę odległości zredukowanej i wysokości względnej między wierzchołkami badanego trójkąta osnowy.

EN

Precise Point Positioning (PPP) is a technique used to determine high accuracy position with a single GNSS receiver. May be an alternative solution to differential measurements, where maintaining a connection with a single Real Time Kinematic (RTK) station or a regional Real Time Network (RTN) of reference stations is necessary. This situation is especially common in areas with poorly developed infrastructure of ground stations. This paper presents the results of a comparative analysis of accuracy of absolute determination of position from observations which last between 0,5 to 6 hours with the use of four permanent free online web 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). For each point of test network, calculations were made using solely GPS observations and taking into account Final products. 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.

3

A comparative study of Precise Point Positioning (PPP) accuracy using online services

Malinowski M., Kwiecień J.

Reports on Geodesy and Geoinformatics

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2016

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Vol. 102

15--31

EN

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.

4

Comparative analysis of satellite measurements calculation results using the postprocessing services: ASG-EUPOS (Poland), APPS (USA) and CSRS (Canada)

Mika M., Kudach J.

Artificial Satellites : Journal of Planetary Geodesy

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2014

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Vol. 49, No. 2

107--123

EN

The publication has a cognitive research character. It presents a comparative analysis of free Internet services in Poland and abroad, used to adjust the data obtained using satellite measurement techniques. The main aim of this work is to describe and compare free tools for satellite data processing and to examine them for possible use in the surveying works in Poland. Among the many European and global services three of them dedicated to satellite measurements were selected: ASG-EUPOS (Poland), APPS (USA) and CSRS (Canada). The publication contains the results of calculations using these systems. Calculations were based on RINEX files obtained via postprocessing service (ASG-EUPOS network) POZGEO D for 12 reference stations in the South Poland. In order to examine differences in results between the ASG-EUPOS, APPS and CSRS the transformation points coordinate to a single coordinate system ETRF 2000 (in force in Poland) was made. Studies have shown the possibility of the calculation in Poland (in postprocessing mode) using the analyzed applications with global coverage.