THE DEEP SPACE POSITIONING SYSTEM (DPS) - NAVIGATOR CONCEPT FOR THE LUNAR GATEWAY

The DPS-Navigator concept is a self-contained autonomous navigation hardware and software system that provides spacecraft on-board navigation throughout the solar system. It answers the question "where am I?" like the Global Positioning System (GPS), but without the need for the satellite infrastructure. For the lunar Gateway, DPS-Navigator would observe lunar landmarks to determine position information and compute orbital maneuvers to maintain the Gateway orbit when the crew is not present or to reduce the crew's dependence on ground-based mission control. The optical-only design is small (25 x 12 x 12 cm) and lightweight, less than 5 kg. Power requirements are less than 12 W with self-contained processing. Data link requirements (infrequent for set-up, monitoring, and maintenance) are less than 50 MB per day. DPS-Navigator leverages prior flight demonstrations of autonomous navigation (DS-1, Deep Impact, Stardust) to provide a more general and robust on-board solution. DPS-Navigator provides precise lunar landmark measurements using narrow angle field of view (FOV) optics and precise pointing knowledge using wide angle FOV optics. A more robust configuration of the DPS-Navigator uses optical and radiometric sensing. For the lunar Gateway, the optical-only version would be sufficient given the abundance of optical targets in the form of lunar surface landmarks. On-board navigation performance results using lunar landmarks are presented in this paper and shown to provide an alternative to traditional deep space network Earth-based radiometric techniques; thus, freeing Earth tracking stations and ground personnel for other support.