EIGEN-GRGS.RL03.MEAN-FIELD: new mean gravity field model for altimetric satellite orbit computation

Jean-Michel Lemoine (CNES/GRGS, France)

CoAuthors

Stéphane Borgogne (Géode&Cie, France); Richard Biancale (CNES/GRGS, France); Sean Bruinsma (CNES/GRGS, France)

Event: 2014 IDS Workshop

Session: Precise orbit modeling and Precise Orbit Determination

Presentation type: Type Oral

We present a new mean gravity field model for the computation of altimetric satellites orbits, EIGEN-GRGS.RL03.MEAN-FIELD.
The time-variable part of this mean field extends to degree and order 80, based on the recent reiteration of the computation of the GRACE time series of solutions performed at CNES/GRGS, named "Release 03".
EIGEN-GRGS.RL03.MEAN-FIELD is complete to degree and order 260.
It is based on EIGEN-6S2 for the part between degree 81 and 260.
The time-variable gravity (TVG) coefficients between degrees 1 and 80 are obtained from a regression on the GRGS-RL03-v1 monthly time series (2003-2012). For degree 2 this TVG part is extended to 1985-2012 through the use of a GRGS SLR-only (Lageos+Lageos-2) solution between 1985 and 2003.
Outside of the measurements period (1985-2012 for degree 2, 2003-2012 for degrees 3 to 80), the gravity field is extrapolated with a zero-slope assumption.
The modeling of the TVG part includes, as was the case for EIGEN-6S2:
Two annual and two semi-annual coefficients
One bias and one drift for each year.
The bias and drift are in general coherent so that the result is a piece wise linear function, except in the case of earthquakes. Three major earthquakes have been introduced in the modelling: Sumatra on 2004/12/26, Concepcion on 2010/02/27 and Sendai on 2011/03/11.
We will present the standards used for the computation, the characteristics of this new mean field and some evaluations in terms of orbit accuracy performance.

 

Oral presentation show times:

RoomStart DateEnd Date
Blue salon Tue, Oct 28 2014,14:00 Tue, Oct 28 2014,14:15
Jean-Michel Lemoine
CNES/GRGS
France
jean-michel.lemoine@get.obs-mip.fr