The U.S. National Grid (USNG) System is an
alpha-numeric reference system that overlays the UTM coordinate system. It is a
Federal Geographic Data Committee (FGDC) standard developed to improve public
safety, commerce, as well as aid the casual GPS user.
[Link to USNG information page]
GARS is an administrative measure used to rapidly and clearly define geographical locations for battle-space coordination, deconfliction and synchronization as well as for large-area search-and-rescue efforts. GARS is global in scope, providing a common language between the services/combatant commands and simplifying communications.