Current State of Precise Point Positioning and Future Prospects and Limitations

Bisnath, Sunil; Gao, Yuting

doi:10.1007/978-3-540-85426-5_71

Cited by 182 publications

(138 citation statements)

References 6 publications

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“…As usual events in industrial applications, frequent re-convergences can totally destroy the practicability of real-time PPP. As a result, a continuous open sky-view is constantly required by most PPP applications to maintain a centimeter-level positioning accuracy (Bisnath and Gao 2007). To relieve this unrealistic requirement and improve the practicability of PPP, Banville and Langley (2009) identified the integer cycle slips caused by such lock losses through differencing between epochs, simply assuming that ionospheric delays canceled out during such differences.…”

mentioning

confidence: 99%

Rapid re-convergences to ambiguity-fixed solutions in precise point positioning

Geng

Meng

Dodson

et al. 2010

J Geod

155

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Integer ambiguity resolution at a single station can be preformed if the fractional-cycle biases are separated from the ambiguity estimates in precise point positioning (PPP). Despite the improved positioning accuracy by such integer resolutions, the convergence to an ambiguity-fixed solution normally requires at least a few tens of minutes. More importantly, such convergences can repeatedly occur on the occasion of losses of tracking locks for many satellites if an open sky-view is not constantly available, consequently totally destroying the practicability of real-time PPP. In this study, in case of such re-convergences, we develop a method in which ionospheric delays are precisely predicted to significantly accelerate integer ambiguity resolutions. The effectiveness of this method consists in two aspects: First, wide-lane ambiguities can be rapidly resolved using the ionospherecorrected wide-lane measurements, instead of the noisy Melbourne-Wübbena combination measurements; second, narrow-lane ambiguity resolution can be accelerated under the tight constraints derived from the ionosphere-corrected unambiguous wide-lane measurements. In the tests at 90 static stations suffering from simulated total loss of tracking locks, 93.3% and 95.0% of reconvergences to wide-lane and narrow-lane ambiguity resolutions can be achieved within 5 s, respectively, even though the time latency for the predicted ionospheric delays is up to 180 s. In the tests at a mobile van moving in a GPS-adverse environment where satellite number significantly decreases and cycle slips frequently occur, only when the predicted ionospheric delays are applied can the rate of ambiguity-fixed epochs be dramatically improved from 7.7% to 93.6% of all epochs. Therefore, this method can potentially relieve the unrealistic requirement of a continuous open skyview by most PPP applications and improve the practicability of real-time PPP. Integer ambiguity resolution at a single station can be preformed if the fractional-cycle biases are separated from the ambiguity estimates in precise point positioning (PPP). Despite the improved positioning accuracy by such integer resolutions, the convergence to an ambiguity-fixed solution normally requires at least a few tens of minutes. More importantly, such convergences can repeatedly occur on the occasion of losses of tracking locks for many satellites if an open sky-view is not constantly available, consequently totally destroying the practicability of real-time PPP. In this study, in case of such re-convergences, we develop a method in which ionospheric delays are precisely predicted to significantly accelerate integer ambiguity resolutions. The effectiveness of this method consists in two aspects: First, wide-lane ambiguities can be rapidly resolved using the ionosphere-corrected wide-lane measurements, instead of the noisy Melbourne-Wübbena combination measurements; second, narrowlane ambiguity resolution can be accelerated under the tight constraints derived from the ionospherecorrected unambiguou...

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mentioning

confidence: 99%

Rapid re-convergences to ambiguity-fixed solutions in precise point positioning

Geng

Meng

Dodson

et al. 2010

J Geod

155

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“…The PPP using clock and orbit products automatically ties the resulting coordinates to the highly-accurate homogenous global International Terrestrial Reference Frame (ITRF2008). The strategy initially used by scientists studying the condition of ionosphere, the motion of continental plates, time transfer and tropospheric parameters estimation, has recently become popular for surveying, precise positioning and even in precision farming Bisnath, and Gao, 2009;Araszkiewicz et al, 2010, Kalita et al, 2014Roberts et al, 2015;Golaszewski et al, 2017, Paziewski et al, 2017. The reason for this is mainly the simplification of processing using PPP software packages or online automatic services calculating positions based on a submitted Receiver Independent Exchange System (RINEX) observation file.…”

Section: Introductionmentioning

confidence: 99%

Application of the Undifferenced GNSS Precise Positioning in Determining Coordinates in National Reference Frames

Krzan

Stępniak

2017

Artificial Satellites

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ABSTRACT:In high-accuracy positioning using GNSS, the most common solution is still relative positioning using double-difference observations of dual-frequency measurements. An increasingly popular alternative to relative positioning are undifferenced approaches, which are designed to make full use of modern satellite systems and signals. Positions referenced to global International Terrestrial Reference Frame (ITRF2008) obtained from Precise Point Positioning (PPP) or Undifferenced (UD) network solutions have to be transformed to national (regional) reference frame, which introduces additional bases related to the transformation process.In this paper, satellite observations from two test networks using different observation time series were processed. The first test concerns the positioning accuracy from processing one year of dual-frequency GPS observations from 14 EUREF Permanent Network (EPN) stations using NAPEOS 3.3.1 software. The results were transformed into a national reference frame (PL-ETRF2000) and compared to positions from an EPN cumulative solution, which was adopted as the true coordinates. Daily observations were processed using PPP and UD multi-station solutions to determine the final accuracy resulting from satellite positioning, the transformation to national coordinate systems and Eurasian intraplate plate velocities. The second numerical test involved similar processing strategies of post-processing carried out using different observation time series (30 min., 1 hour, 2 hours, daily) and different classes of GNSS receivers. The centimeter accuracy of results presented in the national coordinate system satisfies the requirements of many surveying and engineering applications.

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“…La posición de un receptor GNSS de doble frecuencia puede determinarse mediante la técnica conocida como "posicionamiento puntual de precisión" (PPP). Se trata de un método de post-procesado que utiliza observaciones en doble frecuencia de una sola estación y productos precisos de los satélites donde el efecto de la ionosfera se puede eliminar en primer orden mediante una combinación lineal de los observables que se conoce como combinación libre de ionosfera, y así obtener un posicionamiento de precisión del orden de centímetros en modo estático y de decímetros en modo cinemático (Bisnath and Gao, 2007). Sin embargo, las irregularidades en la densidad electróni-ca causan inhomogeneidades en el índice de refracción del medio y por lo tanto en la refractividad de las señales de radiofrecuencia que las atraviesan, por lo que bajo fuertes fluctuaciones de TEC pueden observarse errores significativos en el posicionamiento de precisión (Moreno et al, 2011).…”

Section: Introductionunclassified

Degradación del posicionamiento de precisión originada por irregularidades de plasma ecuatorial

Bilbao¹,

Monge

Rodríguez‐Caderot

et al. 2014

Fís. Tierra

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ResumenLa variabilidad ionosférica constituye una de las principales amenazas sobre las técnicas basadas en GNSS, tanto en la medida de parámetros ionosféricos como en el posicionamiento de precisión. En este trabajo se muestra el efecto de las irregularidades de plasma ecuatorial sobre la pérdida de señal y su influencia en el posicionamiento puntual de precisión. Los resultados ponen de manifiesto la importancia que tiene la capacidad del receptor para no perder la señal proveniente de los satélites GNSS en la precisión del posicionamiento. Palabras clave: ionosfera, GNSS, PPP, irregularidades ionosféricas. Precise positioning accuracy degradation caused by equatorial plasma irregularities AbstractIonospheric variability is one of the main threats to GNSS-based techniques as ionospheric parameters measurement and precise positioning. In this work the effect of equatorial plasma irregularities on signal loss and its influence on the precise point positioning accuracy are shown. These results highlight the importance of the receiver capacity to deal with signal loss and its effects on positioning accuracy.

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Current State of Precise Point Positioning and Future Prospects and Limitations

Cited by 182 publications

References 6 publications

Rapid re-convergences to ambiguity-fixed solutions in precise point positioning

Rapid re-convergences to ambiguity-fixed solutions in precise point positioning

Application of the Undifferenced GNSS Precise Positioning in Determining Coordinates in National Reference Frames

Degradación del posicionamiento de precisión originada por irregularidades de plasma ecuatorial

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