Vincent Garcia (CLS, France)
Event: 2022 IDS Workshop
Session: DORIS network and constellation: status and evolution
Presentation type: Oral
DOI: 10.24400/312072/i03-2022.3655
Abstract
DORIS signals and measurements are synchronized with TAI (International Atomic Time) using Time and Frequency beacons, of which there are five (Toulouse, Papeete, Kourou, Hartebeesthoek, Terre Adélie). These beacons use as a clock reference a combination of a DORIS USO slaved to a cesium atomic clock to generate the 5MHz signal and a GPS receiver to time-tag it. A new, cheaper, smaller and precise equipment is developed by CNES and Timelink to replace this combination. The first results of this new clock equipment will be presented here.
Contribution: IDS22NET-A_new_Time_and_Frequency_reference_for_the_DORIS_beacons.pdf (pdf, 1113 ko)
Corresponding author:
Vincent Garcia
CLS
France
Laurent Soudarin (CLS, France)
Event: 2022 IDS Workshop
Session: DORIS network and constellation: status and evolution
Presentation type: Oral
DOI: 10.24400/312072/i03-2022.3675
Abstract
News from the International DORIS Service since the last workshop.
Contribution: IDS22NET-IDS_news.pdf (pdf, 696 ko)
Corresponding author:
Laurent Soudarin
CLS
France
John MOYARD (CNES, France)
Flavien MERCIER (CNES, France); Alexandre COUHERT (CNES, France)
Event: 2022 IDS Workshop
Session: Precise orbit modeling and Precise Orbit Determination
Presentation type: Oral
DOI: 10.24400/312072/i03-2022.3494
Abstract
The current CNES POE-F DORIS-based orbit solutions combine the adjustment of tropospheric delay corrections and frequency biases/drifts per satellite pass, as well as station heights and horizontal tropospheric gradients per orbit arc, for each beacon. Estimating this full set of parameters can be prone to correlation issues and thus result in the absorption of dynamic and measurement modeling errors. Yet, when two or more satellites fly with a relative proximity, all of these coefficients can benefit from a common adjustment procedure in order to increase their observability.
This paper focuses on such satellite configurations and presents the results obtained in two independent studies: The first one was performed in the context of ESA's Next-Generation Gravity Mission (NGGM) concepts and consisting of two pairs of satellites. For this purpose, the DORIS measurements of the Sentinel-3A and Sentinel-3B altimeter missions were considered. The second study used the DORIS data of the reference Jason3 and Sentinel-6 Michael Freilich altimetry satellites during their tandem phase. The gain in observability brought by these specific configurations is analyzed for the station parameters but also in terms of orbit accuracy.
Contribution: IDS22POD-Combination_of_DORIS_beacon_measurement_parameters_in_CNES_POE-F_orbit_solutions.pdf (pdf, 398 ko)
Corresponding author:
John MOYARD
CNES
France
Jean-Pierre Chauveau (CLS, France)
Event: 2022 IDS Workshop
Session: DORIS network and constellation: status and evolution
Presentation type: Poster
DOI: 10.24400/312072/i03-2022.3654
Abstract
The conflict between Russia and Ukraine has impacts on the DORIS network. Badary's DORIS beacon is turned off at Russia's request, creating a hole in DORIS coverage. To compensate for this loss, CNES and IGN are considering deploying beacons on other sites in the region, requiring agreements to be put in place and work to be carried out, which can take time. An increase of the jamming on the DORIS signals in Eastern Europe is also observed. This presentation will report on these impacts.
Contribution: IDS22NET-Impact_of_the_Russia-Ukraine_war_on_the_DORIS_network.pdf (pdf, 1413 ko)
Corresponding author:
Jean-Pierre Chauveau
CLS
France
Vikash Kumar (IIT KANPUR, India)
Event: 2022 IDS Workshop
Session: Research activities, new applications using DORIS data, new methods of processing DORIS data
Presentation type: Oral
DOI: 10.24400/312072/i03-2022.3242
Abstract
DORIS (Doppler Orbitography and Radio positioning Integrated by Satellite) is a space based piggyback
satellite system which when used as terrestrial measurement system can provide an accuracy of 10cm in absolute position measurement and in the order of sub- cm accuracy in relative measurements. When it rides piggy back on any satellite system can provide an orbital accuracy up to cm level. This space based geodetic measurement technique has been used for the past three decades world over, for precise measurement on the ground as well as on all oceanographic and altimetric satellite missions. The main applications for which it has been employed are for practical societal applications such as prediction of earthquake, monitoring of ocean, climatology etc., This technique can be considered as an important tool for disaster management. DORIS observations are used in Earth systems for defining International Terrestrial Reference Frame (ITRF) which will help in predicting earth movements and can be used effectively in earthquake pre cursor studies. In oceanography it will help in ocean circulation and climatology studies leading to predicting the changing climate which is of prior concern. In atmospheric studies also it will be a great help to Indian meteorological department in analyzing the tropospheric and Ionospheric modelling. Since our Space Research Organization has been launching several satellite missions and DORIS is being used for computation of the precise orbits, this technique has come to stay for a long time. Though this technology has been around for three decades, it has not been introduced in India so far. The National Centre for Geodesy set up by Department of Science and Technology at the IIT Kanpur has set up a Geodesy village in their campus, where this DORIS station has been established. I will be the first one to work on this Space based Geodetic technique in the country, as my PhD topic is for understanding its usage mainly in Societal applications and transfer of this knowledge to Indian scientific community.
Contribution: IDS22RES-DORIS_applications_in_Geodetic_problems.pdf (pdf, 834 ko)
Corresponding author:
Vikash Kumar
IIT KANPUR
India
