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Discovery of new code interference phenomenon in GPS observables / Connor D. Flynn in GPS solutions, vol 23 n° 3 (July 2019)
[article]
Titre : Discovery of new code interference phenomenon in GPS observables Type de document : Article/Communication Auteurs : Connor D. Flynn, Auteur ; Anthony M. McCaffrey, Auteur ; P.T. Jayachandran, Auteur ; Richard B. Langley, Auteur Année de publication : 2019 Article en page(s) : 9 p. Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] analyse spectrale
[Termes IGN] données Doppler
[Termes IGN] données GPS
[Termes IGN] Global Positioning System
[Termes IGN] interférence
[Termes IGN] modulation du signal
[Termes IGN] perturbation ionosphérique
[Termes IGN] scintillation
[Termes IGN] signal GPSRésumé : (auteur) The Global Positioning System (GPS) provides satellite-based navigation signals, which are employed in many fields, including agriculture, transportation, aviation, and military/personal navigation. In an effort to minimize interference among GPS satellites and to enable GPS receivers to discern satellite identity, each satellite is assigned a specific pseudorandom noise (PRN) sequence that is used to modulate the phase of the corresponding signal. The codes that modulate the current GPS landscape are constructed in such a way that cross-correlation among codes is kept to a bounded minimum, which should significantly limit harmful signal interference. In this study, the efficacy of the current PRN-based modulation system is called into question as GPS signal amplitude and carrier phase data over the past decade show frequent interference between satellite signals. Numéro de notice : A2019-197 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10291-019-0858-7 Date de publication en ligne : 29/04/2019 En ligne : https://doi.org/10.1007/s10291-019-0858-7 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92652
in GPS solutions > vol 23 n° 3 (July 2019) . - 9 p.[article]Optimal Doppler-aided smoothing strategy for GNSS navigation / Zebo Zhou in GPS solutions, vol 21 n° 1 (January 2017)
[article]
Titre : Optimal Doppler-aided smoothing strategy for GNSS navigation Type de document : Article/Communication Auteurs : Zebo Zhou, Auteur ; Bofeng Li, Auteur Année de publication : 2017 Article en page(s) : pp 197 - 210 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement du signal
[Termes IGN] code GNSS
[Termes IGN] données Doppler
[Termes IGN] glissement de cycle
[Termes IGN] onde porteuse
[Termes IGN] phaseRésumé : (Auteur) Carrier-phase-smoothed code (CPSC), i.e., smoothing of the code using carrier phases, has widely been used to reduce the code noise in GNSS applications. However, the efficiency of CPSC suffers significantly from cycle slips, interruptions and jitters. The GNSS Doppler, as an instantaneous measurement, is robust and immune to cycle slips and proven useful in GNSS-challenged environments. We develop optimal Doppler-smoothed code based on the principle of minimum variance using the Hatch filter for two typical applications, which are called pure Doppler-smoothed code (PDSC) and continued Doppler-smoothed code. PDSC results from smoothing the code using only Doppler, whereas in case of continued Doppler-smoothed code, the smoothing continues using Doppler once the carrier phase becomes unavailable. Furthermore, in order to refine the Doppler-smoothed code model, a balance factor is introduced for adjusting the contributions of raw code and Doppler measurements to the smoothed code in case the Doppler noise is relatively large. Finally, experiments are carried out to demonstrate the performance of the theory, which verifies its validity and efficiency. Numéro de notice : A2017-016 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1007/s10291-015-0512-y Date de publication en ligne : 20/01/2016 En ligne : https://doi.org/10.1007/s10291-015-0512-y Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83947
in GPS solutions > vol 21 n° 1 (January 2017) . - pp 197 - 210[article]A frequency-domain imaging algorithm for highly squinted SAR mounted on maneuvering platforms with nonlinear trajectory / Zhenyu Li in IEEE Transactions on geoscience and remote sensing, vol 54 n° 7 (July 2016)
[article]
Titre : A frequency-domain imaging algorithm for highly squinted SAR mounted on maneuvering platforms with nonlinear trajectory Type de document : Article/Communication Auteurs : Zhenyu Li, Auteur ; Mengdao Xing, Auteur ; Yi Liang, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 4023 - 4038 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications
[Termes IGN] accélération
[Termes IGN] données Doppler
[Termes IGN] mesurage de la fréquence
[Termes IGN] radar à antenne synthétique
[Termes IGN] trajectoire (véhicule non spatial)Résumé : (Auteur) The imagery of highly squinted synthetic aperture radar mounted on maneuvering platforms with nonlinear trajectory is a challenging task due to the existence of acceleration and the cross-range-dependent range migration and Doppler parameters. In order to accommodate these issues, a frequency-domain imaging algorithm based on tandem two-step nonlinear chirp scaling (TNCS) with small aperture is proposed. For the cross-range-dependent range cell migration (RCM) caused by the linear range walk correction and acceleration, the first-step NCS is introduced to suppress this dependence and realize the unified RCM correction. Based on the differences between full-aperture and small-aperture data in the cross-range processing, the second-step NCS is introduced in frequency domain to equalize the cross-range-dependent Doppler parameters, for cross-range processing is more sensitive to the cross-range dependence than range processing. Furthermore, a novel geometric correction method based on inverse projection is utilized to eliminate the negative effects caused by the imaging processing. Simulation results and real data processing are presented to validate the proposed approach. Numéro de notice : A2016-877 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2016.2535391 En ligne : https://doi.org/10.1109/TGRS.2016.2535391 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83040
in IEEE Transactions on geoscience and remote sensing > vol 54 n° 7 (July 2016) . - pp 4023 - 4038[article]Use of doppler parameters for ship velocity computation in SAR images / Alfredo Renga in IEEE Transactions on geoscience and remote sensing, vol 54 n° 7 (July 2016)
[article]
Titre : Use of doppler parameters for ship velocity computation in SAR images Type de document : Article/Communication Auteurs : Alfredo Renga, Auteur ; Antonio Moccia, Auteur Année de publication : 2016 Article en page(s) : pp 3995 - 4011 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications
[Termes IGN] analyse discriminante
[Termes IGN] détection de cible
[Termes IGN] données Doppler
[Termes IGN] image TerraSAR-X
[Termes IGN] objet mobile
[Termes IGN] vitesse de déplacementRésumé : (Auteur) This paper deals with the exploitation of Doppler centroid measurements for ship velocity estimation from focused single-look complex synthetic aperture radar (SAR) images. An algorithm is presented, which can be used as a discrimination tool to reduce the false alarm rate of standard adaptive threshold detectors and to complement the ship detection task with velocity estimation. The outputs are the indication of the presence of a moving target and the estimate of its slant range velocity. After a review of its theoretical background, algorithm features and performance are verified by application to TerraSAR-X data. The proposed method performs robust Doppler spectrum derivation for candidate ship targets and background pixels. The presented results show that the estimated radial velocity is in very good agreement (5% root-mean-square deviation) with that resulting from the azimuth offset method. Rejection of bright sea features and azimuth ambiguities is also demonstrated, taking advantage of the performed velocity analysis. Numéro de notice : A2016-876 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2016.2533023 En ligne : https://doi.org/10.1109/TGRS.2016.2533023 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83036
in IEEE Transactions on geoscience and remote sensing > vol 54 n° 7 (July 2016) . - pp 3995 - 4011[article]Doppler-aided positioning: Improving single-frequency in the urban environment / M. Bahrami in GPS world, vol 22 n° 5 (May 2011)
[article]
Titre : Doppler-aided positioning: Improving single-frequency in the urban environment Type de document : Article/Communication Auteurs : M. Bahrami, Auteur ; Marek Ziebart, Auteur Année de publication : 2011 Article en page(s) : pp 47 - 56 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] données Doppler
[Termes IGN] effet Doppler
[Termes IGN] géonavigateur
[Termes IGN] lissage de données
[Termes IGN] mesurage de pseudo-distance
[Termes IGN] milieu urbain
[Termes IGN] positionnement cinématique en temps réel
[Termes IGN] récepteur monofréquenceRésumé : (Editeur) What do a GPS receiver, a policeman’s speed gun, a weather radar, and some medical diagnostic equipment have in common? Give up? They all make use of the Doppler effect. First proposed in 1842 by the Austrian mathematician and physicist, Christian Doppler, it is the change in the perceived frequency of a wave when the transmitter and the receiver are in relative motion. Doppler introduced the concept in an attempt to explain the shift in the color of light from certain binary stars. Three years later, the effect was tested for sound waves by the Dutch scientist Christophorus Buys Ballot. [...] The beginning of the space age heralded a new application of the Doppler effect. By measuring the shift in the received frequency of the radio beacon signals transmitted by Sputnik 1 from a known location, scientists were able to determine the orbit of the satellite. And shortly thereafter, they determined that if the orbit of a satellite was known, then the position of a receiver could be determined from the shift. That realization led to the development of the United States Navy Navigation Satellite System, commonly known as Transit, with the first satellite being launched in 1961. Initially classified, the system was made available to civilians in 1967 and was widely used for navigation and precise positioning until it was shut down in 1996. The Soviet Union developed a similar system called Tsikada and a special military version called Parus. These systems are also assumed to be no longer in use — at least for navigation. GPS and other global navigation satellite systems use the Doppler shift of the received carrier frequencies to determine the velocity of a moving receiver. Doppler-derived velocity is far more accurate than that obtained by simply differencing two position estimates. But GPS Doppler measurements can be used in other ways, too. In this month’s column, we look at how Doppler measurements can be used to smooth noisy code-based pseudoranges to improve the precision of autonomous positioning as well as to improve the availability of single-frequency real-time kinematic positioning, especially in urban environments. Numéro de notice : A2011-180 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30958
in GPS world > vol 22 n° 5 (May 2011) . - pp 47 - 56[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 067-2011051 RAB Revue Centre de documentation En réserve L003 Disponible Delay-Doppler analysis of bistatically reflected signals from the ocean surface: theory and application / T. Elfouhaily in IEEE Transactions on geoscience and remote sensing, vol 40 n° 3 (March 2002)PermalinkTectonic interpretation of the Papua New Guinea region from repeat satellite measurements / K. Mobbs (1997)PermalinkDoppler satellite control and its application in the Egyptian geodetic network / M. Elhoseny in Survey review, vol 30 n° 235 (01/01/1990)PermalinkPermalinkPermalinkSur la technique "LOS" en planètologie / Georges Balmino (1988)PermalinkReport on the performance, analysis and interpretation of doppler- and laser measurements / Bernhard Hofmann-Wellenhof (1987)PermalinkEntwicklungsstand der Zeit- und Frequenzmesstechnik und sein Einfluss auf die Leistungsfähigkeit moderner geodätischer Messverfahren / R. Stecher (1986)PermalinkNouvelle méthode de restitution d'orbite précise et d'amélioration du champ de gravité terrestre à partir de mesures Doppler / Richard Biancale (1986)PermalinkDas Geodätische Datum mit Stochastischer Vorinformation / Burkhard Schaffrin (1985)Permalink