Pour savoir comment effectuer et gérer un dépôt de document, consultez le « Guide abrégé – Dépôt de documents » sur le site Web de la Bibliothèque. Pour toute question, écrivez à corpus@ulaval.ca.
 

Personne :
Cocard, Marc

En cours de chargement...
Photo de profil

Adresse électronique

Date de naissance

Projets de recherche

Structures organisationnelles

Fonction

Nom de famille

Cocard

Prénom

Marc

Affiliation

Université Laval. Département des sciences géomatiques

ISNI

ORCID

Identifiant Canadiana

ncf11860357

person.page.name

Résultats de recherche

Voici les éléments 1 - 2 sur 2
  • PublicationRestreint
    Research activities in precise positioning at Laval University
    (Canadian Institute of Geomatics, Vol. 66, (2), 89-101 (2012 ), 2012-03-01) Santerre, Rock; Lamothe, Philippe; Macias-Valadez, Daniel; Kamali, Omid; Bourgon, Stéphanie.; Kirouac, Valérie; Prat, Yann; Cocard, Marc
    This review paper summarises the recent, on-going, and future research activities in precise positioning at Laval University. The projects undertaken by the GPS and Geodesy Research Group are presented following three main research topics. The first one deals with the use of precise positioning for deformation monitoring of engineering structures. The study of ice forces on dams using a robotic total station and the improvement of GPS height determination using multiple GPS antennas linked to a single receiver with calibrated fiber optics are presented. A second topic of research is the crustal deformation of the Charlevoix seismic zone in Quebec. This study uses GPS and levelling techniques and involves an investigation of the temporal stability of the GPS permanent stations available in the surrounding area. Finally, research on single GPS receiver positioning techniques is presented, namely, Precise Point Positioning (PPP) and Time Relative Positioning (TRP).
  • PublicationRestreint
    Single GPS receiver time-relative positioning with loop misclosure corrections.
    (Springer, 2005-10-06) Santerre, Rock; Bourgon, Stéphanie.; Balard, Nicolas.; Cocard, Marc
    Time-relative positioning makes use of observations taken at two different epochs and stations with a single global positioning system (GPS) receiver to determine the position of the unknown station with respect to the known station. The limitation of this method is the degradation over time of the positioning accuracy due to the temporal variation of GPS errors (ionospheric delay, satellite clock corrections, satellite ephemerides, and tropospheric delay). The impact of these errors is significantly reduced by adding to the one-way move from the known to the unknown station, a back move to the known station. A loop misclosure is computed from the coordinates obtained at the known station at the beginning and at the end of the loop, and is used to correct the coordinates of the unknown station. The field tests, presented in this paper, show that using the loop misclosure corrections, time-relative positioning accuracy can be improved by about 60% when using single frequency data, and by about 40% with dual frequency data. For a 4-min processing interval (an 8-min loop) and a 95% probability level, errors remain under 20 cm for the horizontal components and 36 cm for the vertical component with single frequency data; and under 11 cm for the horizontal components and 29 cm for the vertical component with dual frequency data.