A CHAMP‐only gravity field model from kinematic orbits using the energy integral

Abstract

[1] In this paper we present results of a global gravity field recovery using half a year of CHAMP data. We use the energy integral of the motion of a satellite to transform satellite velocities into values of gravitational potential. The feasibility of this approach has already been demonstrated by several groups, using CHAMP reduced-dynamic orbits. We show, that the potential recovered from this kind of orbits depends on the a priori gravity field used for orbit determination. Thus, it cannot be excluded that errors present in the prior field propagate into the new CHAMP gravity model. It is the intention of this paper to avoid this dependency through the use of kinematic orbits, which are free from prior information. The derived potential model, TUM-1S, is validated by comparison to ground data and by satellite orbit residuals. It is shown to be comparable in quality to other state-of-the-art gravity field models.

GPS-derived orbits for the GOCE satellite

“…KIN orbits (Švehla and Rothacher 2005) have also already successfully been generated with the Bernese GPS Software and have been used for gravity field recovery (see, e.g., Gerlach et al 2003;Prange et al 2010). A band-limited part (±4 epochs) of the full covariance matrix of KIN positions is derived in the course of the KIN orbit determination.…”

Instrument data simulations for GRACE Follow-on: observation and noise models

“…Reigber, 1989;Gerlach et al, 2003;Mayer-Gürr, 2006;Rummel, 1979). Therefore, simulated instrument data provide a controlled, closed form medium to test and improve different gravity field recovery techniques.…”

Precise estimation of in situ geopotential differences from GRACE low‐low satellite‐to‐satellite tracking and accelerometer data

“…Alternative approaches, suggested by Jekeli [1999] and Han [2004] were developed on the basis of the energy condition of the satellites and have been proven to provide accurate global gravity field solutions, as demonstrated by analyses of the Challenging Minisatellite Payload (CHAMP) satellite mission data [Han et al, 2002;Gerlach et al, 2003]. Using the CHAMP high-low GPS tracking, three-axis accelerometer and attitude data, the geopotential observations were determined at altitude and used to estimate the corresponding spherical harmonic coefficients representing the Earth's gravity field.…”