Evaluation of Improvements to Precise Orbit Determination and DORIS Geophysical Products Using the Results of Jason-2/T2L2
Abstract
Space geodesy applications currently demand better accuracy and better long-term stability,including the terrestrial reference frame and the Precise Orbit Determination (POD) of Earthobservation satellites. This is why the Global Geodetic Observing System (GGOS) recommendboth an accuracy of 1 mm and a stability of 0.1 mm/y for geodetic networks.The Doppler Orbitography Radiopositioning Integrated on Satellite (DORIS) is a trackingtechnique based on an one way ground to space Doppler link. DORIS shows a robust capabilityin terms of data coverage and availability, due to a wide and well-distributed ground network.However, DORIS residuals remain in the range of 0.35 _ 0.45 mm/s_1, due to systematicserrors (e.g. instabilities of the on-board clock to radiations encountered in space, DORIS timebiases...), which limits the positioning of the beacons, especially for those located in the vicinityof the South Atlantic Anomaly (SAA).The Time Transfer by Laser Link (T2L2) experiment carried on-board the Jason-2 satelliteis a unique opportunity to read the on-board oscillator and extract frequency bias data at alevel of a few parts in 10_13. In addition to the frequency bias residuals deduced from theMedium Ephemeris Orbit (MOE) data, the CARMEN-2 experiment measuring particles flux,internal data (e.g. current, temperature of the DORIS receiver) and an analytical representationof environment-induced signals (e.g. radiation), we built a deterministic frequency model,reducing the DORIS residuals to a level of 0.8 _ 10_12 (0.24 mm/s_1) over several years (2008-2017).In this paper, we evaluate the impact of our new model for the on-board clock on geophysicalproducts, such as beacon positioning, Earth Orientation Parameters (EOP) and precise orbitdetermination for Jason-2.
- Publication:
-
42nd COSPAR Scientific Assembly
- Pub Date:
- July 2018
- Bibcode:
- 2018cosp...42E.259B