Precise orbit determination techniques for a lunar satellite navigation system

The next global strategic priority in space missions is a stable access to the Moon. Over the last few years several studies and discoveries have pushed the space agencies and companies worldwide to numerous feasibility studies to realize permanent infrastructures and assets in cis-lunar environment and on its surface. NASA’s Artemis program to take humans back to the Moon in this decade is a huge driving force in the generation of an economically sustainable path for lunar exploration and resource exploitation, aiming to create a reference point to reach furthest celestial bodies of high interest like Mars. In this framework, Thales Alenia Space is conducting the feasibility study of the Lunar Communications and Navigation Services (LCNS) within European Space Agency's (ESA) Moonlight initiative that will support Artemis space program. The aim of the work presented in this dissertation is to implement a precise Orbit Determination (OD) algorithm to dynamically estimate the state vector of a constellation of satellites that could provide a navigation service in lunar environment. Different scenarios and phases of ESA's Positioning Navigation and Timing (PNT) implementation roadmap were simulated. A key point in the analysis is the interaction between the disparate observables that can be collected in each scenario, ranging from satellite-to-satellite cross-link signals and Deep Space Network(DSN) tracking to altimetric measures and Doppler-based range-rates. A trade-off analysis based on the increasing complexity of the proposed architectures and the respective quality of the OD algorithm was then performed. The implementation of the algorithm and the performance evaluation has been fully carried out in MATLAB environment, while the satellites orbits and Moon's and Earth's infrastructures needed to generate the observables have been simulated with both Systems Tool Kit (STK) and MATLAB High Precision Orbit Propagator(HPOP).