This activity assesses potential system-level scenarios from orbit and clock determination performance perspective (OCD); and defines and evaluates, in a representative scenario, new navigation algorithms.  An enormous DMS/TUM/ADS/ESA joint effort has been performed since Project-KO to TDR-2/NDR-1-KO to produce a representative evaluation of the enhancement on the OCD prediction accuracy (for different on-board clock technologies -- G1G RAFS, G2G RAFS, G2G PHM, G2G ONCLE RRAFS and G2G ONCLE PHM --, and over prediction time  [AOD from 0 up to 100 min]), enabled by the

• Addition of a G2G-dedicated satellite laser ranging network, with modern SLR equipment.
• Extension and modernization of the Galileo sensor stations network.
• Use of Galileo-external ranging data, from European IGS stations at EU territories.
• Addition of inter-satellite links, with high-accuracy ranging and communication capability (see example photograph below).
• Continental augmentation of the space segment by IGSO with or without eccentricity.
   

Moreover, the activity has evaluated (from a fast-track-prototype) the enhancement on the robustness of the orbit and clock determination and prediction function enabled by defining the Galileo System Time as a clock-ensemble (built from both space-borne and ground-based atomic clocks).  Furthermore the activity has defined and analyzed, a simplified integrity monitor, which can identify a relevant SIS anomaly approximately within an hour after its occurrence, (from the ranging data of a global network similar to the Galileo 1st generation GSS).

The activity achieved a very successful TDR-1, and initiated the TDR-2/NRR-1 review process, both in 2018, which completion is expected end of January. The H2020-018.01 activity contributed visibly to the consolidation of the ranging performance requirements at System and Segment level.