Department of Defense. GPS was initially intended for military applications, but in the 1980s the government made the system available for civilian use. GPS works in all weather conditions, anywhere in the world, 24 hours a day. There are no subscription fees or installation fees to use GPS. GPS is made up of three parts: satellites orbiting the Earth; control and monitoring stations on Earth; and user-owned GPS receivers. GPS satellites broadcast signals from space that are picked up and identified by GPS receivers. Each GPS receiver then provides a three-dimensional location (latitude, longitude and altitude) as well as the