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Multi-dimensional particle filter-based estimation of inter-system phase biases for multi-GNSS real-time integer ambiguity resolution / Yumiao Tian in Journal of geodesy, vol 93 n°7 (July 2019)  

Public [article]  inJournal of geodesy > vol 93 n°7 (July 2019) . - pp 1073 - 1087 Titre : Multi-dimensional particle filter-based estimation of inter-system phase biases for multi-GNSS real-time integer ambiguity resolution Type de document : Article/Communication Auteurs : Yumiao Tian, Auteur ; Zhizhao Liu, Auteur ; Frank Neitzel, Auteur Année de publication : 2019 Article en page(s) : pp 1073 - 1087 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] ambiguïté entière [Termes IGN] analyse multidimensionnelle [Termes IGN] constellation GNSS [Termes IGN] erreur systématique inter-systèmes [Termes IGN] filtre [Termes IGN] phase GNSS [Termes IGN] positionnement par GNSS [Termes IGN] précision du positionnement [Termes IGN] résolution d'ambiguïté [Termes IGN] temps réel [Vedettes matières IGN] Traitement de données GNSS Résumé : (auteur) In multi-GNSS integration, fixing inter-system double-difference ambiguities to integers is still a challenge due to the existence of inter-system biases (ISB) when mixed types of GNSS receivers are used. It has been shown that when ISB is known, the inter-system ambiguities can be fixed and the reliability of ambiguity fixing can be improved significantly, especially under poor conditions when the number of observed satellites is small. In traditional methods, the intra-system ambiguity is fixed first; then, the ISB is estimated to ultimately fix the inter-system ambiguity. In our work, we use the particle filter-based method to estimate the ISB parameter and fix the inter-system ambiguities to integers at the same time. This method shows higher reliability and higher ambiguity fixing rate. Nevertheless, the existing particle filter approach for ISB parameter estimation is a one-dimensional algorithm. When satellites from three or more systems are observed, there are two or more ISB parameters. We extend the current one-dimensional particle filter approach to multi-dimensional case and estimate multi-ISB parameters in this study. We first present a multi-dimensional particle filter approach that can estimate multi-ISB parameters simultaneously. We also show that the RATIO values can be employed to judge the quality of multi-dimensional ISB values. Afterward, a two-dimensional particle filter approach is taken as an example to validate this approach. For example, in the experiment of GPS L5, Galileo E5a and QZSS L5 integration with 6 satellites using the IGS baseline SIN0-SIN1, only three ambiguities are resolved to integer when the ISBs are unknown. The integer ambiguity fixing rate is 41.0% with 53% of the ambiguity-fixed solutions having positioning errors larger than 3 cm. However, when our approach is adopted, the number of integer ambiguity parameters increases to five. The integer ambiguity fixing rate increases to 99.7% with 100% of ambiguity-fixed solutions having positioning errors smaller than 3 cm. Numéro de notice : A2019-359 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-018-01226-6 Date de publication en ligne : 29/01/2019 En ligne : https://doi.org/10.1007/s00190-018-01226-6 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93427 [article]

Determining inter-system bias of GNSS signals with narrowly spaced frequencies for GNSS positioning / Yumiao Tian in Journal of geodesy, vol 92 n° 8 (August 2018)  

Public [article]  inJournal of geodesy > vol 92 n° 8 (August 2018) . - pp 873 - 887 Titre : Determining inter-system bias of GNSS signals with narrowly spaced frequencies for GNSS positioning Type de document : Article/Communication Auteurs : Yumiao Tian, Auteur ; Zhizhao Liu, Auteur ; Maorong Ge, Auteur ; Frank Neitzel, Auteur Année de publication : 2018 Article en page(s) : pp 873 - 887 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie spatiale [Termes IGN] ambiguïté entière [Termes IGN] double différence [Termes IGN] erreur systématique inter-systèmes [Termes IGN] fréquence [Termes IGN] positionnement par GNSS [Termes IGN] signal GLONASS [Termes IGN] signal GNSS [Termes IGN] signal GPS Résumé : (Auteur) Relative positioning using multi-GNSS (global navigation satellite systems) can improve accuracy, reliability, and availability compared to the use of a single constellation system. Intra-system double-difference (DD) ambiguities (ISDDAs) refer to the DD ambiguities between satellites of a single constellation system and can be fixed to an integer to derive the precise fixed solution. Inter-system ambiguities, which denote the DD ambiguities between different constellation systems, can also be fixed to integers on overlapping frequencies, once the inter-system bias (ISB) is removed. Compared with fixing ISDDAs, fixing both integer intra- and inter-system DD ambiguities (IIDDAs) means an increase of positioning precision through an integration of multiple GNSS constellations. Previously, researchers have studied IIDDA fixing with systems of the same frequencies, but not with systems of different frequencies. Integer IIDDAs can be determined from single-difference (SD) ambiguities, even if the frequencies of multi-GNSS signals used in the positioning are different. In this study, we investigated IIDDA fixing for multi-GNSS signals of narrowly spaced frequencies. First, the inter-system DD models of multi-GNSS signals of different frequencies are introduced, and the strategy for compensating for ISB is presented. The ISB is decomposed into three parts: 1) a float approximate ISB number that can be considered equal to the ISB of code pseudorange observations and thus can be estimated through single point positioning (SPP); 2) a number that is a multiple of the GNSS signal wavelength; and 3) a fractional ISB part, with a magnitude smaller than a single wavelength. Then, the relationship between intra- and inter-system DD ambiguity RATIO values and ISB was investigated by integrating GPS L1 and GLONASS L1 signals. In our numerical analyses with short baselines, the ISB parameter and IIDDA were successfully fixed, even if the number of observed satellites in each system was small. Numéro de notice : A2018-456 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-017-1100-4 Date de publication en ligne : 14/12/2017 En ligne : https://doi.org/10.1007/s00190-017-1100-4 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91053 [article]

Particle filter-based estimation of inter-frequency phase bias for real-time GLONASS integer ambiguity resolution / Yumiao Tian in Journal of geodesy, vol 89 n° 11 (november 2015)  

Public [article]  inJournal of geodesy > vol 89 n° 11 (november 2015) . - pp 1145-1158 Titre : Particle filter-based estimation of inter-frequency phase bias for real-time GLONASS integer ambiguity resolution Type de document : Article/Communication Auteurs : Yumiao Tian, Auteur ; Maorong Ge, Auteur ; Frank Neitze, Auteur Année de publication : 2015 Article en page(s) : pp 1145-1158 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] ambiguïté entière [Termes IGN] erreur systématique [Termes IGN] phase GPS [Termes IGN] positionnement ponctuel précis [Termes IGN] résolution d'ambiguïté [Termes IGN] signal GLONASS [Termes IGN] temps réel [Termes IGN] variance de phase [Vedettes matières IGN] Traitement de données GNSS Résumé : (auteur) GLONASS could hardly reach the positioning performance of GPS, especially for fast and real-time precise positioning. One of the reasons is the phase inter-frequency bias (IFB) at the receiver end prevents its integer ambiguity resolution. A number of studies were carried out to achieve the integer ambiguity resolution for GLONASS. Based on some of the revealed IFB characteristics, for instance IFB is a linear function of the received carrier frequency and L1 and L2 have the same IFB in unit of length, most of recent methods recommend estimating the IFB rate together with ambiguities. However, since the two sets of parameters are highly correlated, as demonstrated in previous studies, observations over several hours up to 1 day are needed even with simultaneous GPS observations to obtain a reasonable solution. Obviously, these approaches cannot be applied for real-time positioning. Actually, it can be demonstrated that GLONASS ambiguity resolution should also be available even for a single epoch if the IFB rate is precisely known. In addition, the closer the IFB rate value is to its true value, the larger the fixing RATIO will be. Based on this fact, in this paper, a new approach is developed to estimate the IFB rate by means of particle filtering with the likelihood function derived from RATIO. This approach is evaluated with several sets of experimental data. For both static and kinematic cases, the results show that IFB rates could be estimated precisely just with GLONASS data of a few epochs depending on the baseline length. The time cost with a normal PC can be controlled around 1 s and can be further reduced. With the estimated IFB rate, integer ambiguity resolution is available immediately and as a consequence, the positioning accuracy is improved significantly to the level of GPS fixed solution. Thus the new approach enables real-time precise applications of GLONASS. Numéro de notice : A2015-885 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s00190-015-0841-1 En ligne : https://doi.org/10.1007/s00190-015-0841-1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=79424 [article]