To develop or evolve the fundamental techniques, models and algorithms required for the design and development of a future Lunar Radio Navigation system

The interest of having in the near future an available Position, Navigation and Timing (PNT) service supporting future missions to and at the Moon is currently supported by both institutional and commercial initiatives. On the commercial side, multiple companies are developing business solutions targeting the Moon and several major European companies are proposing to team up to build a communications network on the Moon compatible to terrestrial standards. In parallel, NASA has recently announced its plans to a ?Return to the moon? in the next decade and the NASA-ESA Orion space vehicle should be operational early 2021. During this decade, ESA will also contribute to the Gateway station and to robotic missions, such as those within the Heracles program. This activity will develop or evolve fundamental techniques, models and algorithms (independent from a specific Lunar Radio Navigation Concept) including:- Lunar Geodetic frame, elevation models (DEM) and time reference frames suitable for highly accurate navigation;- Assessment of possible Lunar satellite Radio Navigation candidate signals;- Precise orbit determination techniques satellites of the lunar radio navigation system;- Lunar User PNT algorithms and identification of critical technologies at user levelThis activity encompasses the following tasks:- Review of the state of the art- Identification of possible solutions and available technologies suitable for the Moon system and assessment of the performances- Identification of the aspects that do not meet the expected performances and definition of novel techniques/technologies to cover the gap- Definition of a preliminary development plan for the required techniques, models and algorithms to achieve the required performances