The Copernicus Precise Orbital Determination (CPOD) service is responsible for generating and validating orbital and auxiliary products for the Sentinel-1, -2, -3 and -6 missions. Now the CPOD team has improved the accuracy of the service’s outputs by incorporating a new time variable gravity field model into its data processing procedures.
Precise estimation of a satellite’s orbit is essential for mission operations and supports the exploitation of the data its instrumentation collects, by facilitating the planning of acquisitions and data processing.
The CPOD service delivers products to support ESA’s Copernicus ground segment and EUMETSAT’s Copernicus ground segment, as well as the data user community. It is operated by technology business group GMV, which leads a consortium of space agencies, universities and commercial companies with expertise in precise orbit determination.
The Copernicus Precise Orbital Determination (CPOD) service is responsible for generating and validating orbital and auxiliary products for the Sentinel-1, -2, -3 and -6 missions. Now the CPOD team has improved the accuracy of the service’s outputs by incorporating a new time variable gravity field model into its data processing procedures.
Copyright: ESA
Illustration of Copernicus Sentinel-3
Precise estimation of a satellite’s orbit is essential for mission operations and supports the exploitation of the data its instrumentation collects, by facilitating the planning of acquisitions and data processing.
The CPOD service delivers products to support ESA’s Copernicus ground segment and EUMETSAT’s Copernicus ground segment, as well as the data user community. It is operated by technology business group GMV, which leads a consortium of space agencies, universities and commercial companies with expertise in precise orbit determination.
CPOD also benefits from a dedicated Quality Working Group composed of top-level experts with world renowned experience in global navigation satellite systems (GNSS) and precise orbit determination. It is formed of members of the CPOD consortium as well as selected specialists from Europe and beyond.
With the support of the Quality Working Group, CPOD engineers are continuously striving to enhance the service, whose accuracy is directly influenced by inputs such as GNSS data and gravity field measurements.
To advance this objective, GMV recently deployed operationally a new and improved model for the generation of gravity field data, following an extensive period of analysis and validation.
Called the COST-G Fitted Signal Model, it draws on contributions from different analysis centres that are combined and integrated by experts at the University of Bern (AIUB) in Switzerland.
The model is generated based on data delivered by the joint NASA and German Aerospace Center (DLR) Gravity Recovery and Climate Experiment Follow-on (GRACE-FO) mission, ensuring that it reflects recent changes in gravity field conditions.
Copyright: AIUB
COST-G Fitted Signal Model
An in-depth analysis found that, when compared to CPOD’s previous gravity field model, the new COST-G model results in improvements in all observed precise orbit determination metrics, including reduction of GNSS carrier phase residuals, improvement in orbital comparisons between the CPOD quality working group solutions, and reduction of empirical signals.
The implementation of the COST-G model was presented and endorsed by CPOD’s Quality Working Group at its annual meeting held in June 2023.
CPOD products are currently available via the Copernicus Open Access Hub and are expected to be accessible through the recently launched Copernicus Data Space Ecosystem in the coming months.
The COST-G Fitted Signal Model replaces the EIGEN-GRGS-RL04 mean gravity field model, which was used between 2019 and 2023.
The CPOD consortium includes GNSS and precise orbit determination specialist PosiTim, the German Aerospace Center (DLR), the Technical University of Delft, the GFZ German Research Center for Geosciences, and the Technical University of Munich.
The CPOD Quality Working Group includes, in addition to the consortium members, experts from the French Space Agency (CNES), AIUB, and NASA’s Jet Propulsion Laboratory and Goddard Spaceflight Center, among others.