Carrier-Phase Aided Pseudo-Noise Range Estimation at RF Frequencies

There is renewed interest in cis-lunar space exploration, including both robotic and human space missions in the near future. However, current CCSDS ranging standards do not include proximity links or spacecraft-to-spacecraft scenarios that will be required by future missions to the Moon and beyond. For example, the current CCSDS Pseudonoise (PN) ranging standard assumes that a terrestrial ground station always defines one end of the link, achieving roughly one meter ranging accuracy under nominal conditions. Spacecraft situational awareness and demanding docking operations require cm-level accuracy, far beyond the capabilities of current Earth-based PN-code based ranging techniques. In this paper, we address these new requirements and demonstrate an algorithm capable of achieving the ranging accuracy needed for docking and lunar landing applications in the new cis-lunar environment.