Designing a Satellite Navigation System for the Moon

The Moon is entering a new era of exploration, with dozens of commercial, national, and international missions planned for the coming decade. Supporting this activity will require robust Positioning, Navigation, and Timing (PNT) infrastructure - a "Lunar GPS" - capable of serving spacecraft, landers, and rovers across the cislunar domain. In this talk, I will present my research on building the algorithmic and systems foundations for a "Lunar GPS." First, I will outline the key challenges in enabling such a system compared to Earth, including precise orbit determination and time synchronization without surface stations, a unique dynamical environment, the definition of new coordinate and time frames, and tighter size, weight, and power constraints. Second, I will describe how terrestrial GNSS signals, including weak sidelobe transmissions that spill beyond Earth, can be leveraged for precise orbit determination and timekeeping of lunar satellites, with particular attention to ionospheric and plasmaspheric delay modeling as a critical bottleneck to achieving meter-level accuracy. Time permitting, I will broaden the perspective to extending satellite radionavigation beyond the Earth-Moon system, including collaborative work with NASA JPL on next-generation Mars navigation and communication relay networks, and emerging opportunities, such as precise timing for low-frequency radio astronomy arrays on the lunar farside, that a mature Lunar GPS infrastructure could uniquely enable.

Speaker: Keidai Iiyama, Stanford University

Roonm 350/372