The Terrafirma project funded by ESA has been a precursor to the European Ground Motion Service (EGMS) activity of EEA in the framework of the Copernicus programme. Terrafirma is also a precursor to the GEP with PSI service chains implemented and used to support geoscience centres such as geological surveys. The GEP has been inspired by this project and expanded the capability looking at cost-effective on-line solutions and more processing techniques, Radar and Optical. Back in 2008, as part of Terrafirma, a large validation activity was conducted and the following reports are shared on the GEP and available to users:
Crossetto, M., Monserrat, O., Adam, N., Parizzi, A., Bremmer, C., Dortland, S., Hanssen, R.F. & van Leijen, F.J. (2008). Validation of existing processing chains in Terrafirma stage 2, Final report: https://esamultimedia.esa.int/docs/EarthObservation/ValProj.pdf; and associated appendix.
Hanssen, R.F., van Leijen, F.J., van Zwieten G.J., [PhB1] Bremmer, C., Dortland, S. & Kleuskens, M. (2008). Validation of existing processing chains in Terrafirma stage 2, Validation in the Amsterdam and Alkmaar area, https://esamultimedia.esa.int/docs/EarthObservation/ValProj-Detailed-Report.pdf
The GEP is a processing environment to support geoscience users and it is intended that it will provide them with access to the open and free products generated by the EGMS. The R&D environment of the GEP will be linked to the operational Copernicus EGMS capability to help grow access and use of EO based services for the geohazard community.
More about the EGMS: