Ohjaaja Pasi Laurila, Soveltuvuus Suomessa · 2015
Tämän opinnäytetyön tavoitteena on selvittää Precise Point Positioning-mittausta ja sen soveltuvuutta mittauksiin Suomen leveysasteella. Olen suorit-tanut opinnäytetyötä varten omia mittauksia sekä käyttänyt kiinteiden tu-kiasemien dataa, jotka olen ratkaissut käyttäen Precise Point Positioning-mittausmoodia. Omissa mittauksissani olen käyttänyt referenssinä pisteen RTK-ratkaisua sekä staattisella mittaustavalla ratkaistuja koordinaatteja. Korkeus-tarkkuuden arvioimiseksi olen vaainnut korkeuden lähimmästä korkeuspultista. Vaikka PPP-mittaus on mainittu ensimmäisen kerran jo 1970-luvulla, vasta 1990-luvulla Jet Propulsion Laboratory (JPL NASA) julkisti PPP-mittauksen teo-reettisen taustan, joka ei tarvinnut erotushavaintoja tarkan paikan määräämi-seksi. Tekniikka nimettiin Precise Point Positioning, PPP. Precise Point Posi-tioning-mittauksessa käytetään ainoastaan yhtä GNSS-vastaanotinta. JPL jul-kaisi ensimmäisen tutkimuksen yhden, kaksitaajuus GPS-laiteen datan laske-misesta muutaman senttimetrin tarkkuudella vuonna 1997. Suomen leveysasteella PPP-mittaus on kuitenkin ongelmallinen. Skandinavian alueella on ollut useita jääkausia, jotka painoivat maankuorta alas. Maankuoren palautuminen ja mannerlaatan liike aiheuttavat ongelmia PPP-mittauksen pai-kallisissa ratkaisuissa. Jos ratkaisu halutaan laskea Suomessa käytetyissä koordinaattijärjestelmissä, mittaus on pystyttävä palauttamaan kyseisissä järjes-telmissä käytettyihin epookkeihin. Esimerkiksi EUREF-FIN-koordinaattijärjes-telmä yhtyy kansainväliseen ITRS-järjestelmään epookkina vuosi 1989.
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Jakub Nosek · Brno University of Technology Digital Library (Brno University of Technology) · 2020
Tato diplomová práce se zabývá testováním metody Precise Point Positioning (PPP) v různých variantách. V práci jsou popsány teoretické základy metody PPP a nejdůležitější systematické chyby, které ovlivňují její přesnost. Přesnost metody byla vyhodnocována na datech z permanentní GNSS stanice CADM, která je součástí výzkumného centra AdMaS. Zpracovány byly data z období 2018 – 2019. Porovnávány byly výsledky kombinací různých GNSS a výsledky různě dlouhých observací. Na závěr bylo provedeno ověření přesnosti na 299 GNSS stanicích IGS.
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A.V. Voytenko, В. Л. Быков · Geodesy and Cartography · 2016
This article contains general information about the precise method of differential positioning, known as «Precise Point Positioning» (PPP). The article listed the developers of this method and the authors of publications about it. The paper presents the code and carrier phase pseudorange models, which are used in PPP. It is given a shot description of the code signals
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Patrick Henkel · 2019
Precise Point Positioning (PPP) enables an absolute positioning with centimeter-level accuracy without the need of raw measurements from a reference station. However, today's GPS L1/ L2-based PPP solutions typically need more than 30 minutes to converge. In this paper, we present a PPP solution with a much faster convergence using the proposed next-generation GNSS Kepler. We exploit the high accuracy of the satellite position, clock offset and bias estimates enabled by highly accurate optical inter-satellite range measurements. We additionally exploit the low noise level of the E1, E5 and E6 pseudorange measurements based on wideband signals as provided already by Galileo. Our PPP solution determines the receiver position and clock offset, tropospheric and ionospheric zenith delays, and pseudorange multipath errors without the need of any prior information. We show that the PPP convergence time can be reduced from more than 30 minutes to less than 5 minutes with Kepler.
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A. El-mowafy · 2012
The method of precise point positioning (PPP) using un-differenced code and carrier phase observations in combination with measurement corrections is discussed. The implementation of PPP in mobile mapping is addressed. Two approaches are investigated. In the first, measurement corrections optimized for the work area, including atmospheric corrections, are wirelessly received from a local service provider operating a local real-time GPS reference network. In the second approach, only precise orbits and clock corrections received from an international service provider through the Internet are used. One major problem of relying on wireless corrections is the possibility of facing interruptions in reception of the measurement corrections, which would result in the deterioration of the PPP performance. A method is presented to solve this problem, in which the orbital, clock and wet tropospheric corrections stored during operation are lumped together, predicted in real time as a time series and used in the PPP mode when breaks of signal reception take place. To improve system reliability and to accelerate the process of phase ambiguity resolution, particularly when using global corrections, a dual-antenna system fixed on board the mobile mapping vehicle is utilized. The two antennae are also used to determine the orientation of the mapping sensors by determining the heading and pitch of the vehicle. An adaptive Kalman filtering approach is utilized in the system. The filter is used to adaptively reflect dynamics changes in vehicle trajectory through the use of a measurement residual sequence. Testing of the system showed that it has a good overall performance. It can achieve centimeter to decimeter positioning accuracy, and attitude determination accuracy at the arc-minute level. 1.
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Nosek, Jakub · Brno University of Technology Digital Library (Brno University of Technology) · 2020
Tato diplomová práce se zabývá testováním metody Precise Point Positioning (PPP) v různých variantách. V práci jsou popsány teoretické základy metody PPP a nejdůležitější systematické chyby, které ovlivňují její přesnost. Přesnost metody byla vyhodnocována na datech z permanentní GNSS stanice CADM, která je součástí výzkumného centra AdMaS. Zpracovány byly data z období 2018 – 2019. Porovnávány byly výsledky kombinací různých GNSS a výsledky různě dlouhých observací. Na závěr bylo provedeno ověření přesnosti na 299 GNSS stanicích IGS.
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Christof Völksen · 2009
Precise Point Positioning (PPP) can be used for a wide range of applications in geodetic positioning. Providing precise clock and orbit information, a single station can be positioned in a reference frame. This leads to a very efficient processing procedure since the normal equation system is very small compared to network processing. PPP achieves very robust solutions comparable to network solutions. A drawback of PPP is that it does not respect the principle of adjacent points, because correlations between neighbouring stations are not considered. This drawback leads to a disadvantageous stochastic behaviour between adjacent stations. However, as the point positions are computed using identical orbit and clock information, correlations between the estimated coordinates still remain. The presentation focus on this fact and determines correlations between station coordinates. Generally geodetic positioning using the Global Positioning System (GPS) is based on the processing of simultaneously observed GPS data from several stations. Coordinate estimation with highest precision is performed using relative positioning. Forming single and later double differences between satellites and receivers eliminates the common errors contained in the GPS phase and code observations. (Algorithms based on undifferenced observations work similar and
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R. J. Anderle · 1976
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Sunil Bisnath, Paul Collins · GEOMATICA · 2012
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Nacer Naciri, Sunil Bisnath · NAVIGATION Journal of the Institute of Navigation · 2023
<h3>Abstract</h3> Global navigation satellite system (GNSS) precise point positioning (PPP) has potential as an alternative or replacement for real-time kinematic (RTK) processing. In this work, we reached for RTK levels of performance without the need for local information through PPP (i.e., centimeter-level positioning that was reached near-instantaneously). This work makes use of information currently available from processing signals from global positioning system (GPS), Galileo, BeiDou-2/3, and GLONASS by fixing ambiguities for the first three constellations on all available frequencies. This processing was done using a four-frequency, four-constellation uncombined decoupled clock model (DCM) that has been expanded as part of this work. The results were tested on 1448 global datasets and showed that instantaneous convergence on average to 2.5 cm error can be achieved for 81% of the stations. These findings were reinforced by the results of epoch-by-epoch processing, as an average of 80% of all single epochs converged below 2.5 cm error at 1σ, as opposed to less than the 0.5% typically observed for classic PPP.
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Sueo Sugimoto, Yukihiro Kubo · Proceedings of the ISCIE International Symposium on Stochastic Systems Theory and its Applications · 2005
In this paper, a new real-time kinematic (RTK) algorithm for carrier-phase-based precise point positioning based on Global Navigation Satellite System (GNSS) regression models which the authors firstly introduce in the present paper. The derived RTK positioning algorithm may achieve the positioning accuracy in decimeter level, and will be possibly centimeter level.
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Simon Banville · 2014
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Changhui Xu, Jinling Wang · 2011
With the development of iono-free solution, provision of IGS orbit and clock products, high precision GNSS positioning with a single receiver, usually named Precise Point Positioning (PPP), has been playing an increasingly important role in many applications. PPP is to obtain the highly precise coordinates of the receivers, so it is necessary to establish the mathematical model according to the mechanism of the motion of the platform and geometric relationship for the measurements used. The commonly used method to describe these motion and relationship is the Gauss-Markov models which are then used in the Kalman filter, to produce optimal estimation of the parameters, only when the model is realistic. However, it is well known that GPS/GNSS measurements may be contaminated with outliers, which will certainly have an impact on the reliability of the results, and even the convergence period. If these outliers are not correctly identified, the results may be biased and the precision will be decreased. Therefore, it is necessary to analyse the outlier detection performance first. The experiment demonstrates that the internal reliability gives the minimal detectable bias of 4cm in carrier phases and 3.5m in pseudo-ranges under the given priori variance and the effects of undetectable bias on the states is at the millimetre level after convergence. KEYWORDS:Precise Point Positioning, Outlier Detection, Reliability 1
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Patrick Henkel · 2020
Precise Point Positioning (PPP) provides accurate absolute position information without the direct need of measurements from a reference station at the user. The current challenge of GPS L1/L2-based PPP is its long convergence time of more than 20 minutes being caused by the need to estimate atmospheric parameters, and the relatively large code noise and multipath errors. There are two options to reduce the convergence time of PPP: First, the Galileo wideband signals on E5 and E6 have a much lower code noise than current GPS L1 and L2 pseudoranges. Second, the satellite positions and satellite-related biases can be determined much faster and more accurately with optical inter-satellite links supporting ranging, time-transfer and intra-system communication. In this paper, we consider both options. A joint estimation of the receiver position, receiver clock offset, tropospheric zenith delay, ionospheric slant delays and carrier phase ambiguities is performed with a Kalman filter. Orbital errors and pseudo range multipath are also taken into account. The float carrier phase ambiguity estimates are mapped to integers using the famous Least-Squares Ambiguity Decorrelation Adjustment (LAMBDA) method. The simulation results show that an ambiguity fixing and, thereby, a highly-accurate PPP solution, can be achieved consistently within a few epochs. This is a quite substantial benefit and could make PPP attractive for numerous applications.
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Thomas Grinter, Clive Roberts · 2011
The concept of Precise Point Positioning (PPP) using Global Navigation Satellite System (GNSS) technology was first introduced in 1976. However, it took until the 1990s for PPP to generate interest amongst the greater GNSS community. Over the last two decades, dual-frequency PPP has been extensively researched, and several PPP online services and software packages have been developed. This research has shown that centimetre-level point positioning is not only achievable in postprocessed static mode, but potentially also for real-time applications, with a single GNSS receiver. With the advent of cost-effective, accurate, Real-Time Kinematic (RTK) positioning provided by an increasing number of Continuously Operating Reference Station (CORS) networks around the world, the focus of PPP has shifted to real-time or near real-time solutions. Real-time and near real-time correction products from organisations such as the National Aeronautics and Space Administration (NASA) Jet Propulsion Laboratory (JPL), the International GNSS
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Moreno Monge, Beatriz, Rodríguez Caderot, Gracia, Lacy de, M.C. · Library Open Repository (Universidad Complutense Madrid) · 2014
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Ge, M., Li, X., Dousa, J. et al. · Publication Database GFZ (GFZ German Research Centre for Geosciences) · 2011
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Orviská, Terézia · Brno University of Technology Digital Library (Brno University of Technology) · 2023
Cieľom tejto diplomovej práce je porovnanie presnosti a rýchlosti konvergencie metódy Precise Point Positioning (PPP) a PPP s celočíselným riešením ambiguit a posúdiť využiteľnosť metódy PPP v súvislosti s odhadom magnitúd zemetrasení. V práci sú popísané teoretické základy GNSS metódy PPP a dôležité systematické chyby a spôsoby ich eliminácie. Následne je predstavené riešenie praktickej časti. Dáta sú spracovávané z obdobia roka 2020 na 14 vybratých permanentných staniciach IGS. Výpočtu PPP predchádzalo kvalitatívne hodnotenie dát. Vo výsledku vykazuje metóda PPP s celočíselným riešením ambiguit s nekombinovanými observáciami najkonzistentnejšie a najpresnejšie výsledky s najrýchlejšou konvergenciou. Pre výpočet magnitúd boli vybraté 3 zemetrasenia na Aljaške z obdobia 2020-2021 a boli skúmané 4 kombinácie metód, pričom najlepšie výsledky poskytla znovu metóda PPP s celočíselným riešením ambiguit s nekombinovanými observáciami.
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Z. Wen, P. Henkel, and C. Günther · mediaTUM – the media and publications repository of the Technical University Munich (Technical University Munich) · 2013
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Beatriz Moreno Monge, G. Rodrı́guez-Caderot, M. C. de Lacy · GPS Solutions · 2013
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