The objective of this activity is to define, design and predevelop an advanced PRS payload antenna subsystem for future EU LEO-PNT, addressing classified requirements. This activity belongs to Galileo/EGNOS Upstream R&D which is part of the space component of Horizon Europe, under which, in line with the signed FFPA and relevant Contribution Agreement, ESA is delegated by the European Commission to manage this activity. ESA adapted procurement rules will apply as per the ITT to be published (open Competition in 2 stages). ESA reserves the right to place one parallel Contract subject to weighted quality of the proposal of at least 60 points, budget availability and related programmatic decision.