Position, Navigation, and Timing Solutions for Lunar Robotic Applications

<p>As lunar exploration advances toward long-term, high-level missions, the demand for reliable Position, Navigation, and Timing (PNT) systems on the Moon is growing rapidly. However, due to the absence of a dedicated lunar navigation infrastructure, alternative methods must be developed and evaluated to support surface operations and spacecraft positioning. This paper investigates and compares three PNT solutions through simulation. The solutions are singlesatellite two-way ranging, Joint Doppler-Ranging (JDR), and Earth-based passive positioning.</p> <p>Each solution was implemented in MATLAB and compared to the original works and then validated. Once validated, the three different architectures were compared to one another via performance metrics. Position accuracy, convergence time, signal latency, and visibility were analyzed under similar conditions across various lunar surface locations, including the South Pole, North Pole, and Equator.</p> <p>Results show that the two-way ranging system achieved convergence at the lunar South Pole but suffered from limited visibility at other locations resulting in extremely large errors. The JDR system offered good geometric diversity and consistent visibility, though it required a longer convergence period. The Earth-based passive system delivers instantaneous positioning with</p> <p>relatively high accuracy but exhibits increased signal latency and limited geometric strength due to transmitter distribution and distance between the Moon and the Earth.</p> <p>This work demonstrates that no single architecture is ideal in all cases, and trade-offs must be considered based on mission requirements. These findings provide insight into the feasibility of different lunar PNT approaches and lay the groundwork for future studies involving dynamic users, varied orbits, and conditions which are not ideal.</p>