Safe navigation requires accurate and precise charts or maps and navigational tools for locating a vessel within those maps. These charts and maps are based upon the foundation of a high accuracy reference system, which includes basic physical models used navigation tools. Thus, a complete reference system includes a reference frame and those physical models needed to navigate, all with the objective to ensure any given vessel will reach the same point regardless of the navigation technology used. On Earth, the National Geospatial-Intelligence Agency (NGA) maintains the World Geodetic System 1984 (WGS 84) reference system to meet its Congressionally-mandated Safety of Navigation mission. The WGS 84 system includes the WGS 84 reference frame and its realization, the Earth Gravitational Model (EGM) with its Geoid, and the World Magnetic Model (WMM). While based upon sound science, the development and maintenance of the WGS 84 is continuous development of existing models, rather than basic science. The WGS 84 enables both civilian and Department of Defense (DoD) users to safely and accurately position and navigate. As the United States returns to the Moon with an eye towards supporting commercial civilian activity, lunar navigation moves from limited, government-run exploration missions to broader business-driven activities. A standard, publicly available reference system will be necessary to enable safe lunar navigation for all users. NGA is developing a Lunar Reference System following the WGS 84 model. This presentation will describe the WGS 84 and outline the development for a similar reference system on the Moon.