Day 4

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Paper title Precise Orbit Determination of the Spire Satellite Constellation for Geodetic, Geophysical, and Ionospheric Applications - Project Overview and First Orbit Determination Results
  1. Adrian Jäggi Astronomical Institute of the University of Bern Speaker
  2. Heike Peter PosiTim UG
  3. Daniel Arnold University of Bern, Astronomical Institute
  4. Lucas Schreiter GFZ German Research Center for Geosciences
  5. Ulrich Meyer University of Bern
Form of presentation Poster
  • B6. National missions TPM
    • B6.01 National EO satellite missions
Abstract text The main objective of the project “Precise Orbit Determination of the Spire Satellite Constellation for Geodetic, Geophysical, and Ionospheric Applications” (ID no. 66978), which was approved on 7 September 2021 in the frame of an ESA Announcement of Opportunity (AO), is to generate and validate precise reference orbits for selected Spire satellites and, based on this, to ingest and assess the requested Spire GPS data into three scientific applications, namely gravity field determination, reference frame computations, and ionosphere modelling to study the added value of the Spire GPS data. Due to the fact that the Spire constellation populates for the first time the Low Earth Orbit (LEO) layer at different inclinations with a large number of satellites, which are all equipped with high-quality dual-frequency GPS receivers, it opens the door to significantly strengthen all of the three above mentioned scientific applications.

In the initial phase of the project the focus will be on the precise orbit determination (POD) of selected Spire satellites. Two independent, state-of-the art software packages, namely the Bernese GNSS Software and ESA’s NAPEOS software, will be used for this purpose. This will allow for inter-comparisons, a role model that is inherited from the work of the POD Quality Working Group of the Copernicus POD service. It will enable an independent quality and integrity assessment of the Spire inputs and products.

We will analyse the quality of the Spire GPS code and carrier phase date and validate antenna phase centre calibrations. Based on this we will determine reduced-dynamic and kinematic orbits for selected Spire satellites. Eventually we will evaluate the quality of the reconstructed orbits by means of orbit overlap analyses, cross-comparisons of kinematic and reduced-dynamic orbits computed within one and the same software, and cross-comparisons of the orbits derived with the Bernese GNSS Software and ESA’s NAPEOS software, as well as comparisons to the orbits provided by Spire.