GBOT - one year before Gaia's launch

International audienceGBOT (Ground Based Optical Tracking, [1]) is a part of the Gaia satellie mission, which is being set up to be able to fully exploit the capabilities of the satellite, even for the best measured stars. The GBOT project consists of about half a dozen small (1-2 m class telescopes), which will make daily observations of the Gaia space craft. From these data, the GBOT group will derive astrometric positions, which will be used in the reconstruction of Gaia's orbit

Web interface for lunar laser ranging observations

International audienceWe report the current development of a web interface for the preparation and the validation of Lunar Laser Ranging (LLR) observations. With this service which is not yet completely implemented at the time of this presentation, distant LLR observers will be able to easily run some Paris observatory tools used for the lunar motion. It will allow them to compute predictions of geocentric and topocentric coordinates of lunar targets (as retro-reflectors and craters) and predictions of round-trip times of laser-pulses between terrestrial stations and lunar retro-reflectors. It will also allow them to compare their own LLR observations with computations (lunar solutions and reduction models), in terms of rms, and with a real-time access

Web interface for lunar laser ranging observations

International audienceWe report the current development of a web interface for the preparation and the validation of Lunar Laser Ranging (LLR) observations. With this service which is not yet completely implemented at the time of this presentation, distant LLR observers will be able to easily run some Paris observatory tools used for the lunar motion. It will allow them to compute predictions of geocentric and topocentric coordinates of lunar targets (as retro-reflectors and craters) and predictions of round-trip times of laser-pulses between terrestrial stations and lunar retro-reflectors. It will also allow them to compare their own LLR observations with computations (lunar solutions and reduction models), in terms of rms, and with a real-time access

Web interface for lunar laser ranging observations

International audienceWe report the current development of a web interface for the preparation and the validation of Lunar Laser Ranging (LLR) observations. With this service which is not yet completely implemented at the time of this presentation, distant LLR observers will be able to easily run some Paris observatory tools used for the lunar motion. It will allow them to compute predictions of geocentric and topocentric coordinates of lunar targets (as retro-reflectors and craters) and predictions of round-trip times of laser-pulses between terrestrial stations and lunar retro-reflectors. It will also allow them to compare their own LLR observations with computations (lunar solutions and reduction models), in terms of rms, and with a real-time access

Comparative study of the EOP series derived for the second IVS Pilot Projet

International audienc

Comparative study of the EOP series derived for the second IVS Pilot Projet

International audienc

Comparative study of the EOP series derived for the second IVS Pilot Projet

International audienc

Combinaisons GPS VLBI au niveau des équations normales par DYNAMO

National audienc

Combinaisons GPS VLBI au niveau des équations normales par DYNAMO

National audienc

VO-Compatible Architecture for Managing and Processing Images of Moving Celestial Bodies : Application to the Gaia-GBOT Project

International audienceThe Ground Based Optical Tracking (GBOT) group is a part of the Data Processing and Analysis Consortium, the large consortium of over 400 scientists from many European countries, charged with the scientific conduction of the Gaia mission by ESA. The GBOT group is in charge of the optical part of tracking of the Gaia satellite. This optical tracking is necessary to allow the Gaia mission to fully reach its goal in terms of astrometry precision level. These observations will be done daily, during the 5 years of the mission, with the use of optical CCD frames taken by a small network of 1-2m class telescopes located all over the world. The requirements for the accuracy on the satellite position determination, with respect of the stars in the field of view, are 20 mas. These optical satellite positions will be sent weekly by GBOT to the SOC of ESAC and used with other kinds of observations (radio ranging and Doppler) by MOC of ESOC to improve the Gaia ephemeris. For this purpose, we developed a set of accurate astrometry reduction programs specially adapted for tracking moving objects. The inputs of these programs for each tracked target are an ephemeris and a set of FITS images. The outputs for each image are: a file containing all information about the detected objects, a catalogue file used for calibration, a TIFF file for visual explanation of the reduction result, and an improvement of the fits image header. The final result is an overview file containing only the data related to the target extracted from all the images. These programs are written in GNU Fortran 95 and provide results in VOTable format (supported by Virtual Observatory protocols). All these results are sent automatically into the GBOT Database which is built with the SAADA freeware. The user of this Database can archive and query the data but also, thanks to the delegate option provided by SAADA, select a set of images and directly run the GBOT reduction programs with a dedicated Web interface. For more information about SAADA (an Automatic System for Astronomy Data Archive under GPL license and VOcompatible), see the related paper Michel et al. (2013)