Copernicus POD Service – Impact of High Solar activity on POD

The Copernicus Precise Orbit Determination (CPOD) Service delivers, as part of the Ground Segment of the Copernicus Sentinel-1, -2, -3, and -6 missions, orbital products and auxiliary data files for their use in the corresponding Payload Data Ground Segment (PDGS) processing chains at ESA and EUMETSAT, and to external users through the newly available Copernicus Data Space Ecosystem (https://dataspace.copernicus.eu/).

For the last few years, a progressive degradation of the accuracy of some of the CPOD orbital products has been observed, caused by the increasing solar activity. Solar activity follows an 11-year cycle, and since the minimum in 2020, overall solar activity has been higher and geomagnetic storms have been happening more often. This has two impacts on POD: a more “turbulent” atmosphere which brings higher frequency density changes, making the modelling of the satellite´s drag more challenging, and an increase of ionospheric scintillation, particularly over the polar regions, that causes an increase of the GNSS carrier phase noise.

This study aims at characterising better the impact of the solar activity on the different POD products, with a focus on the degradation of orbit determination and predictions required by the Sentinel-1 mission. Overall tendencies since the solar minimum in 2020 are analysed, including a detailed look on strong geomagnetic storms. Mitigation strategies to overcome this situation are evaluated, namely adapting the POD processing dynamic parametrisation, and updating the solar activity proxies (particularly the geomagnetic indexes) more frequently.