What is GPS (Global Positioning System)?

Ø    Global Positioning System (GPS) is a space-based radio-positioning and time transfer system constellation of 24 satellites developed, launched, and maintained by the United States Air Force that provides positioning, timing, and navigation signals free of charge to both military and civilian users worldwide. GPS satellites orbit the earth every 12 hours, emitting continuous navigation signals that enables properly equipped users to determine precise time and velocity and worldwide latitude, longitude and altitude to within a few meters. In addition to the satellites, the system consists of a worldwide satellite control network and GPS receiver units that acquire the satellite's signals and translate them into precise position and timing information. The signals are so accurate that time can be figured to much less than a millionth of a second, velocity can be figured to within a fraction of a mile per hour, and location can be figured to within a few sub-meters or better with the right equipment. The receivers do not send out any signals, or communicate back to the satellites. In addition, the FAA’s Wide Area Augmentation System (WAAS) has become a critical component of a seamless satellite navigation system which improves the accuracy, availability, and integrity of GPS. GPS has proven beneficial in the commercial and civil markets for transportation, surveying and rescue operations and are used to locate features such as manholes, fire hydrants, bridges, road centerlines, buildings, and etc.

Ø   Ohio Valley Regional Development Commission has entered the Global Positioning System (GPS) world by purchasing a Trimble GeoExplorer GeoXT GPS unit with ESRI ArcPad 6.0.3, Trimble’s GPScorrect, and Trimble’s GPS Pathfinder Office Software. The GeoXT is a submeter accuracy receiver that can track up to 12 satellites, with real time corrections from a satellite-based augmentation system (SBAS) like WAAS1 or EGNOS2. The GPS receiver and antenna are built into the handheld computer that is cable-free The GeoXT is a very powerful handheld unit that help extends OVRDC’s GIS/GPS capabilities.