LuPNT: Open-Source Simulator for Lunar Positioning, Navigation, and Timing

The growing focus on missions to the Moon necessitates reliable Positioning, Navigation, and Timing (PNT) services in cis-lunar space. This paper introduces a comprehensive, open-source simulation framework developed to address the growing research need in this field. Implemented primarily in C++ for computational efficiency, the framework also includes Python bindings to facilitate rapid algorithmic development and user interaction. The simulation core employs an event-based architecture to model asynchronous onboard applications and inter-satellite communication. Lunar dynamics modeling, incorporating planetary ephemerides, high-order gravitational effects, third-body perturbations, and solar radiation pressure, is also integrated. This framework’s modular and extensible architecture allows for broad applicability across various research applications, from the performance analysis of Lunar Navigation Satellite System (LNSS) constellations to the assessment of orbit determination algorithms and lunar navigation payloads. In addition to describing the architectural and algorithmic facets of the framework, the paper presents two use cases demonstrating its efficacy in onboard orbit determination and timing.