Design, development, and verification of an algorithm for Timing Synchronization of assets in orbit and on the surface of the Moon

Since the increased interest in Moon exploration has grown from worldwide space institutions in the latest years, stable access to this natural satellite is again a top space priority. The European Space Agency (ESA)’s Moonlight initiative, born in support of NASA’s Artemis program to take humans back to the Moon, is one of the long-term existing projects that encourage many space companies to place a constellation of telecommunications and navigation satellites around the Moon. Providing dedicated and reliable lunar telecommunications and navigation services can reduce design complexity, costs, and constraints of future missions, allowing them to concentrate on their core tasks. In the context of the feasibility studies for future Lunar Communication and Navigation Services (LCNS), Thales Alenia Space Italia (TASI) is defining a candidate concept design for a Lunar Radio Navigation System (LRNS), mainly in terms of suitable Orbit Determination (OD) and Time Synchronization (TS) techniques. The purpose of the work disserted in this thesis is the study, design, development, and verification of a Time Synchronization algorithm suitable for this kind of proposals. It has to provide a dynamic estimation of the clock offset coefficients of the timing reference on board a lunar satellite to allow a user, in orbit or on the surface of the Moon, correcting for its time offset with respect to the reference system timescale. With this objective, a survey on principal Space Atomic Frequency Standard (SAFS), Master Clock stations technologies, and time transfer techniques is conducted. In a trade-off with innovative techniques and performing technologies as driving goals, the scenario of a one-way time transfer among Global Navigation Satellite System (GNSS) and lunar constellations of satellites, as well as the state-of-the-art of miniaturized SAFS technologies as timing reference on-board, the miniRAFS, a simulator is implemented. It involves the development of an Input Simulator, that reproduces the principal timing offset contributions in residual pseudoranges affecting the observables collected, and a Kalman Filter (KF), that computes the real-time estimations. The algorithm is prototyped both for single and multiple observables, besides, the effect of impacting residual relativistic error is outlined. A validation algorithm is then applied to verify if the software satisfies the set-out requirements in terms of maximum timing error contribution in the Lunar Ephemeris Error (LEE) in the frame in which it is to be used. Accuracies on the order of tens of nanoseconds are obtained. The development of the simulator has been entirely carried out in MATLAB environment by making use of tools, functions, and files system.