grid reference system

attitude-and-heading reference system / attitude and heading reference system (AHRS)

military grid reference system (MGRS)

grid reference box

grid zone / grid-zone

grid zone designation / Grid Zone Designator

call for fire using `snail` grid reference

JAN grid / Joint Army-Navy grid

grid reference code

grid reference

grid coordinate system

guidance reference system

numbered reference position system

World Geographic Reference System (WGRS); georef

muzzle reference system (MRS)

inertial reference system

strapdown attitude heading reference system

strapdown inertial reference system

vertical reference system

attitude-and-heading reference system (AHRS)

heading and attitude reference system

replacement attitude and heading reference system

map-grid coordinate system

attitude and heading reference system (AHRS)

Joint Army-Navy grid system

world geographic reference system

grid communications system

grid-square numbering system

grid system of communications

fire extinguishing system sprinkler system and fire alarm system

bearing grid angle

Global Information Grid (GIG)

grid azimuth