DOD uses satellite-based GPS for critical operations with its aircraft, ships, munitions, land vehicles, and ground troops. DOD is developing positioning, navigation, and timing technology to complement GPS or as an alternative when GPS is unavailable. We looked at challenges DOD faces in developing and fielding these new technologies, and identified policy options to help address them. For example, the level of precision that GPS provides may not be needed for all applications. Clarifying the performance requirements for new technologies—instead of defaulting to GPS-level precision—could help get appropriate technology into the field faster.