GSTM2022-38
https://doi.org/10.5194/gstm2022-38
GRACE/GRACE-FO Science Team Meeting 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

New Versions of the AEI-derived LRI1B dataset

Laura Müller1,2, Vitali Müller1,2, Malte Misfeldt1,2, Henry Wegener1,2, Yihao Yan1,2, Markus Hauk1,3,4, Pallavi Bekal1,2,5, Simon Bähre1,2, and Gerhard Heinzel1,2
Laura Müller et al.
  • 1Max Planck Institute for Gravitational Physics (Albert Einstein Institute), Hannover, Germany
  • 2Institut für Gravitationsphysik, Leibniz Universität Hannover, Hannover, Germany
  • 3Institut für Satellitengeodäsie und Inertialsensorik, Deutsches Zentrum für Luft- und Raumfahrt (DLR), Hannover, Germany
  • 4Helmholtz Center Potsdam - GFZ German Research Centre for Geosciences, Potsdam, Germany
  • 5Institut für Umweltphysik, Universität Bremen, Bremen, Germany

The inter-satellite distance changes of the GRACE Follow-On spacecraft are measured by the main science instrument, the K-Band Ranging (KBR) system, and by the new Laser Ranging Interferometer (LRI), which exhibits a higher precision. The official ranging data is provided by the Science Data System (SDS) in the so-called KBR1B and LRI1B data products, which are available in the latest version v04. However, the Albert Einstein Institute (AEI) in Hannover is deriving alternative LRI1B data products (v50+v52). These data sets allow us to investigate different processing strategies that might improve the quality of the ranging data.

We will present the most important processing steps for the AEI-derived data products and compare them to the official SDS v04 data. The main differences in the processing regard

  • the deglitching algorithm, which is essential to remove disturbances induced by thruster activations or by single event upsets
  • transformation of LRI time-tags to GPS time using a smooth and at day-bounds continuous correction formed by CLK1B, TIM1B, datation reports and empirical offsets obtained by daily cross-correlating KBR and LRI (only v50)
  • conversion of phase-to-range using a novel formula that was published recently and that can utilize a time-depend laser frequency (scale factor)
  • light-time-correction using alternative formulas that are expected to be more precise
  • tilt-to-length (TTL) coupling correction, which is similar to the antenna offset correction (AOC) in KBR1B but missing in LRI1B v04 so far.

Furthermore, we have implemented a quality flag to indicate special events such as sun-blinding periods or momentum transfer events that might reduce the quality of the ranging data. This allows to down-weight affected segments during gravity field recovery. By comparing LRI1B v04 and AEI-derived LRI1B data, a verification and validation of the official dataset is possible. We will conclude with some examples where the LRI1B data quality can be improved compared to the v04 results.

Our LRI1B datasets are available at:  https://www.aei.mpg.de/grace-fo-ranging-datasets

How to cite: Müller, L., Müller, V., Misfeldt, M., Wegener, H., Yan, Y., Hauk, M., Bekal, P., Bähre, S., and Heinzel, G.: New Versions of the AEI-derived LRI1B dataset, GRACE/GRACE-FO Science Team Meeting 2022, Potsdam, Germany, 18–20 Oct 2022, GSTM2022-38, https://doi.org/10.5194/gstm2022-38, 2022.

Displays

Display file