Scale Factor Determination for the GRACE Follow-On Laser Ranging Interferometer Including Thermal Coupling

verfasst von
Malte Misfeldt, Vitali Müller, Laura Müller, Henry Wegener, Gerhard Heinzel
Abstract

The GRACE follow-on satellites carry the very first interspacecraft Laser Ranging Interferometer (LRI). After more than four years in orbit, the LRI outperforms the sensitivity of the conventional Microwave Instrument (MWI). However, in the current data processing scheme, the LRI product still needs the MWI data to determine the unknown absolute laser frequency, representing the “ruler” for converting the raw phase measurements into a physical displacement in meters. In this paper, we derive formulas for precisely performing that conversion from the phase measurement into a range, accounting for a varying carrier frequency. Furthermore, the dominant errors due to knowledge uncertainty of the carrier frequency as well as uncorrected time biases are derived. In the second part, we address the dependency of the LRI on the MWI in the currently employed cross-calibration scheme and present three different models for the LRI laser frequency, two of which are largely independent of the MWI. Furthermore, we analyze the contribution of thermal variations on the scale factor estimates and the LRI-MWI residuals. A linear model called Thermal Coupling (TC) is derived, which significantly reduces the differences between LRI and MWI to a level where the MWI observations limit the comparison.

Organisationseinheit(en)
Institut für Gravitationsphysik
QuantumFrontiers
SFB 1464: Relativistische und quanten-basierte Geodäsie (TerraQ)
Externe Organisation(en)
Max-Planck-Institut für Gravitationsphysik (Albert-Einstein-Institut)
Typ
Artikel
Journal
Remote sensing
Band
15
ISSN
2072-4292
Publikationsdatum
18.01.2023
Publikationsstatus
Veröffentlicht
Peer-reviewed
Ja
ASJC Scopus Sachgebiete
Erdkunde und Planetologie (insg.)
Elektronische Version(en)
https://doi.org/10.48550/arXiv.2207.11470 (Zugang: Offen)
https://doi.org/10.3390/rs15030570 (Zugang: Offen)