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Coastal GNSS-R phase altimetry based on the combination of L1 and L5 signals under high sea states / Yunqiao He in Journal of geodesy, vol 97 n° 2 (February 2023)  

Public [article]  inJournal of geodesy > vol 97 n° 2 (February 2023) . - n° 19 Titre : Coastal GNSS-R phase altimetry based on the combination of L1 and L5 signals under high sea states Type de document : Article/Communication Auteurs : Yunqiao He, Auteur ; Fan Gao, Auteur ; Tianhe Xu, Auteur ; et al., Auteur Année de publication : 2023 Article en page(s) : n° 19 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] diffusion de Rayleigh [Termes IGN] hauteurs de mer [Termes IGN] niveau de la mer [Termes IGN] phase GNSS [Termes IGN] précision altimétrique [Termes IGN] Quasi-Zenith Satellite System [Termes IGN] rapport signal sur bruit [Termes IGN] récepteur bifréquence [Termes IGN] réflectométrie par GNSS [Termes IGN] signal GNSS [Vedettes matières IGN] Altimétrie Résumé : (auteur) High-precision sea surface heights retrieved from the Global Navigation Satellite System Reflectometry (GNSS-R) measurements will be valuable in the fields of geodesy and oceanography studies. Due to the short wavelengths and low power of GNSS signals, the continuously tracked carrier phase measurements of reflected signals are usually unavailable for sea surfaces with big roughness, varying over space and time. In coastal conditions, persisting spatial coherence assumption can be made within the antenna coverage when the waves are not greatly breaking. To deal with temporal incoherence, we propose an improved algorithm to extract the combined interferometric phase difference measurements between direct and reflected signals under high sea states. After initial tracking the direct signals, dual-frequency observations are combined in the complex domain and the resulting interferometric signal is refined through open-loop tracking with 60-s coherent integration before the phase difference measurements are extracted, without tracking their respective carrier phase measurements in advance. In order to verify our method, a coastal experiment under different sea conditions was conducted and raw intermediate frequency data were collected. The raw data were then processed by a GNSS-R software-defined receiver to compute the path delay measurements of Quasi-Zenith Satellite System signals, which had good visibility during our experiment. For high sea states, that is, when the Rayleigh criterion is not fulfilled for the individual wavelengths, the phase delay measurements of L1 and L5 were random over time, while phase delay can still be well recovered for their combination. Also, the phase delay combination can be well extracted with a higher elevation angle than the previous studies. Finally, the altimetry solutions derived from the carrier phase delay measurements combination were compared with the in situ observations from a 26-GHz radar altimeter. The results show that centimeter-level altimetry accuracy using the combined measurements of L1 and L5 can be achieved under high sea states. Numéro de notice : A2023-132 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-023-01712-6 Date de publication en ligne : 27/03/2023 En ligne : https://doi.org/10.1007/s00190-023-01712-6 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102675 [article]

Toward BDS/Galileo/GPS/QZSS triple-frequency PPP instantaneous integer ambiguity resolutions without atmosphere corrections / Jun Tao in GPS solutions, vol 26 n° 4 (October 2022)  

Public [article]  inGPS solutions > vol 26 n° 4 (October 2022) . - n° 127 Titre : Toward BDS/Galileo/GPS/QZSS triple-frequency PPP instantaneous integer ambiguity resolutions without atmosphere corrections Type de document : Article/Communication Auteurs : Jun Tao, Auteur ; Guo Chen, Auteur ; Jing Guo, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : n° 127 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] ambiguïté entière [Termes IGN] correction atmosphérique [Termes IGN] erreur de phase [Termes IGN] fréquence multiple [Termes IGN] positionnement par BeiDou [Termes IGN] positionnement par Galileo [Termes IGN] positionnement par GPS [Termes IGN] positionnement ponctuel précis [Termes IGN] Quasi-Zenith Satellite System [Termes IGN] résolution d'ambiguïté [Termes IGN] temps de convergence Résumé : (auteur) Multi-frequency precise point positioning (PPP) has drawn attention along with the modernization of the Global Navigation Satellite Systems. There are now nearly 90 satellites providing multi-frequency signals. This contribution aims to achieve fast convergence of a few seconds for BDS/Galileo/GPS/QZSS integrated triple-frequency PPP with integer ambiguity resolution (IAR) without atmosphere corrections. A unified model of an uncombined and undifferenced manner for PPP-IAR with dual- and triple-frequency observations is presented. The uncalibrated phase delays (UPD) of extra wide-lane (EWL), wide-lane (WL), and N1 ambiguities for triple-frequency PPP are estimated with standard deviations of 0.02, 0.05, and 0.10 cycles achieved, respectively. The PPP-IAR validation based on 20 stations evenly distributed in China is conducted using UPD products generated from a regional network covering a large part of China. The EWL, WL, and N1 ambiguities are sequentially fixed utilizing the least-squares ambiguity decorrelation adjustment (LAMBDA) technique. In terms of convergence time, PPP instantaneous IAR is achievable without using atmosphere corrections, thanks to the contribution of the multi-frequency and multi-constellation observations. This has been proved by performing PPP-IAR restart every 10-min over 2520 times in our case study. For PPP-IAR solutions produced with BDS/Galileo/GPS/QZSS triple-frequency observations with an interval of 1 s, the convergence is fulfilled within 1 s for the horizontal components with an accuracy of better than 5 cm, while 2 s for the vertical component with better than 10 cm accuracy, and both are at 95% confidence level. Numéro de notice : A2022-714 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10291-022-01287-3 Date de publication en ligne : 13/08/2022 En ligne : https://doi.org/10.1007/s10291-022-01287-3 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101595 [article]

Evaluation of QZSS orbit and clock products for real-time positioning applications / Brian Bramanto in Journal of applied geodesy, vol 16 n° 3 (July 2022)  

Public [article]  inJournal of applied geodesy > vol 16 n° 3 (July 2022) . - pp 165 - 179 Titre : Evaluation of QZSS orbit and clock products for real-time positioning applications Type de document : Article/Communication Auteurs : Brian Bramanto, Auteur ; Irwan Gumilar, Auteur Année de publication : 2022 Article en page(s) : pp 165 - 179 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] décalage d'horloge [Termes IGN] données GNSS [Termes IGN] perturbation orbitale [Termes IGN] positionnement cinématique en temps réel [Termes IGN] qualité du signal [Termes IGN] Quasi-Zenith Satellite System [Termes IGN] retard ionosphèrique Résumé : (auteur) The Quasi-Zenith Satellite System (QZSS) is the recent Japanese satellite positioning system to enhance the positioning accuracy in Japan’s urban areas. Additionally, they provide precise orbit and clock corrections and can be obtained through their experimental signals (LEX), streaming access, and published site. Multi-GNSS Advanced Demonstration tool for Orbit and Clock Analysis (MADOCA) is one of the precise products offered in QZSS services that can be obtained on a global scale. In this study, we evaluated the performance of MADOCA orbit and clock corrections, particularly for real-time positioning applications using LEX signals. Based on the simulation, we predict that 16 countries in the East Asia and Oceania regions will gain the maximum benefit of the LEX signals. However, we stress that one may have difficulties decoding the LEX signals at regions where only one QZSS satellite is observed. During our sailing expedition at Sumatran Sea, we could only decode up to 37 % LEX signals for the observation period. It profoundly increased up to 95 % at Sulawesi Strait where at least three QZSS satellites with an elevation angle of, at its minimum, 40° were observed. The orbit and clock accuracy is estimated to be 5.2 cm and 0.6 ns with respect to International GNSS Service (IGS) final products. Our simulation of using the Real-Time Precise Point Positioning (RTPPP) method revealed that the accuracy of the corresponding positioning applications was less than one decimeter. Further, we compared the MADOCA products for RTPPP applications with Apex5 positioning solutions in static field observations. The positioning accuracy for MADOCA-RTPPP during the field observations was estimated to be centimeter to decimeter level and is slightly worse than Apex5 positioning solutions. Nevertheless, we highlight vast positioning applications using MADOCA-RTPPP, e. g., survey and mapping, smart agriculture, and offshore engineering navigation. Numéro de notice : A2022-494 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1515/jag-2021-0064 Date de publication en ligne : 03/02/2022 En ligne : https://doi.org/10.1515/jag-2021-0064 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100981 [article]

A comprehensive assessment of four-satellite QZSS constellation: navigation signals, broadcast ephemeris, availability, SPP, interoperability with GPS, and ISB against GPS / Xuanping Li in Survey review, vol 54 n° 382 (January 2022)  

Public [article]  inSurvey review > vol 54 n° 382 (January 2022) . - pp 17 - 33 Titre : A comprehensive assessment of four-satellite QZSS constellation: navigation signals, broadcast ephemeris, availability, SPP, interoperability with GPS, and ISB against GPS Type de document : Article/Communication Auteurs : Xuanping Li, Auteur ; Pan Lin, Auteur ; Wenkun Yu, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : pp 17 - 33 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement [Termes IGN] analyse comparative [Termes IGN] éphémérides de satellite [Termes IGN] erreur systématique inter-systèmes [Termes IGN] interopérabilité [Termes IGN] positionnement par GPS [Termes IGN] précision du positionnement [Termes IGN] qualité du signal [Termes IGN] Quasi-Zenith Satellite System Résumé : (auteur) In this study, a comprehensive assessment of four-satellite Quasi-Zenith Satellite System (QZSS) constellation is conducted, including the quality of navigation signals, the accuracy of broadcast ephemeris, the availability of satellite constellation, the performance of single point positioning (SPP), the interoperability with GPS, and the inter-system bias (ISB) against GPS. Regarding the signal quality, no significant difference between QZSS and GPS can be found. The signal-in-space ranging error (SISRE) of QZSS satellites is 0.59–0.62 m. The service rate of QZSS-only positioning is 69.8–77.8% in QZSS service areas. A positioning accuracy of 5.70, 3.20 and 6.99 m in east, north and up directions can be achieved for the QZSS-only SPP. After introducing QZSS observations into GPS-only SPP processing, the positioning accuracy can be slightly improved. The ISB with a short-term stability of 1.75 ns behaves like systematic biases, and thus cannot be ignored in the GPS/QZSS combined SPP. Numéro de notice : A2022-112 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00396265.2020.1858256 Date de publication en ligne : 11/12/2020 En ligne : https://doi.org/10.1080/00396265.2020.1858256 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99629 [article]

GNSS/INS Kalman filter integrity monitoring with uncertain time correlated error processes / Omar Garcia Crespillo (2022)  

Public Titre : GNSS/INS Kalman filter integrity monitoring with uncertain time correlated error processes Type de document : Thèse/HDR Auteurs : Omar Garcia Crespillo, Auteur ; Jan Skaloud, Directeur de thèse ; Michael Meurer, Directeur de thèse Editeur : Lausanne : Ecole Polytechnique Fédérale de Lausanne EPFL Année de publication : 2022 Importance : 180 p. Format : 21 x 30 cm Note générale : bibliographie Thèse présentée pour l'obtention du grade de Docteur ès Sciences Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement [Termes IGN] corrélation temporelle [Termes IGN] couplage GNSS-INS [Termes IGN] filtre de Kalman [Termes IGN] fréquence multiple [Termes IGN] modèle d'erreur [Termes IGN] modèle de Gauss-Markov [Termes IGN] navigation inertielle [Termes IGN] norme [Termes IGN] positionnement par GNSS [Termes IGN] Receiver Autonomous Integrity Monitoring [Termes IGN] système d'extension Résumé : (auteur) Safety-critical navigation applications require that estimation errors be reliably quantified and bounded. Over the last decade, significant effort has been put to guarantee a bounded position estimation by using Global Navigation Satellite Systems (GNSS) by means of satellite-based or ground-based augmentation systems (SBAS, GBAS) and Advanced Receiver Autonomous Integrity Monitoring (ARAIM) for aviation. This has been achieved by carefully designing models that overbound the different residual error components in range measurements (e.g., satellite clock and orbit, tropospheric and multipath among others). On the other hand, and as part of Aircraft based Augmentation Systems (ABAS), the use of Inertial Reference Systems (IRS) has been traditionally included as additional source of redundant navigation information. More recently, the use of Inertial Navigation Systems (INS) with a wider spectrum of possible inertial sensor qualities in tighter integration with single-frequency GNSS has seen its way in a new Minimum Operational Performance Standard (MOPS). New GNSS/INS systems and standards could still benefit from the methodologies and aspects developed for future dual-frequency/multiconstellation GNSS standards. However, safety-related GNSS systems like ARAIM are snapshot-based, that is, the position estimation is performed independently at every epoch, whereas GNSS/INS systems are typically based on Kalman filtering (KF). Therefore, the existing error overbounding models and methodologies are not enough to produce a robust KF position estimation since the impact of time-correlation in measurements must also be accounted for. Moreover, it has been observed that the time-correlation of different GNSS errors presents also some level of uncertain behavior, which makes very challenging for linear dynamic systems to produce a guaranteed solution. As proposed by GNSS Minimum Operational Performance Standards (MOPS), there are sources of time-correlated errors that can be well modelled using a first order Gauss-Markov process (GMP). Using this GMP parametric model, it is possible to capture the uncertain timecorrelated nature of error processes by allowing the variance and time correlation constant of the GMP model to be in a bounded range. Under this situation, the first part of this thesis studies the propagation of the uncertain models through the Kalman filter estimation and provides new theoretical tools in time and frequency domain to bound the KF error estimation covariance. As a result, tight stationary bounding models on the GMP uncertain processes are derived in both continuous and discrete time domain. This is extended to non-stationary models that provide tighter error bounding during an initial transient phase when measurements are first introduced (which will be relevant in scenarios with changing number of visible satellites). The new models can very easily be used during the KF implementation which might be very attractive by regulators and designers. In the second part of the thesis, the new overbounding GMP models are applied for a dual-frequency GPS-Galileo tightly-coupled GNSS/INS integration. The design of the filter and of error models is performed following compatibility with current aviation standards and ARAIM Working Group C results. The impact of the use of the new models is analysed in terms of conservativeness, integrity and continuity based on realistic operational simulations linked to airport runways. The benefit of an overbounded GNSS/INS solution is also compared with the current baseline ARAIM algorithm solution. This thesis supports the evolution of safe GNSS-based positioning systems from only snapshot based to filtered solutions. Ensuring integrity for Kalman filter in general and for GNSS/INS systems in particular is a game changer to achieve higher performance levels for future dualfrequency multi-constellation aviation services and is of vital importance for new ground and air applications like autonomous vehicles or urban air mobility. Note de contenu : Introduction 1- Preliminaries 2- Bounding Kalman Filter with uncertain error processes 3- Application to GNSS/INS integraty monitoring 4- Closing 5- Appendix Numéro de notice : 28688 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Note de thèse : Thèse de Doctorat : Sciences : Lausanne : 2022 DOI : sans En ligne : https://infoscience.epfl.ch/record/292087?ln=fr Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100103

Ionospheric tomographic common clock model of undifferenced uncombined GNSS measurements / German Olivares-Pulido in Journal of geodesy, vol 95 n° 11 (November 2021)  

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GPS + Galileo + QZSS + BDS tightly combined single-epoch single-frequency RTK positioning / Shaolin Zhu in Survey review, vol 53 n°376 (January 2021)  

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SBAS-aided GPS positioning with an extended ionosphere map at the boundaries of WAAS service area / Mingyu Kim in Remote sensing, vol 13 n° 1 (January-1 2021)  

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Estimation and representation of regional atmospheric corrections for augmenting real-time single-frequency PPP / Peiyuan Zhou in GPS solutions, vol 24 n° 1 (January 2020)  

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Galileo and QZSS precise orbit and clock determination using new satellite metadata / Xingxing Li in Journal of geodesy, vol 93 n° 8 (August 2019)  

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Improving multi-GNSS ultra-rapid orbit determination for real-time precise point positioning / Xingxing Li in Journal of geodesy, vol 93 n° 1 (January 2019)  

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Etude de faisabilité et choix optimal d'une station RIMS d'EGNOS en Algérie / Tabti Lahouaria in XYZ, n° 157 (décembre 2018 - février 2019)

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EGNOS monitoring prepared in Space Research Centre P.A.S. for SPMS project / Anna Swiatek in Artificial satellites, vol 52 n° 4 (December 2017)  

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Tropospheric delay modelling for the EGNOS augmentation system / Kamil Kazmierski in Survey review, vol 49 n° 357 (December 2017)  

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An investigation into the performance of real-time GPS + GLONASS Precise Point Positioning (PPP) in New Zealand / Ken Harima in Journal of applied geodesy, vol 11 n° 3 (September 2017)  

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