(GPS) Global Positioning System

What is GPS?

As of 2007, the United States NAVSTAR Global Positioning System (GPS) is the only fully operational Global Navigation Satellite System (GNSS). Utilizing a constellation of at least 24 medium Earth orbit satellites that transmit precise microwave signals, the system enables a GPS receiver to determine its location, speed/direction, and time. GPS has become a widely used aid to navigation worldwide, and a useful tool for map-making, land surveying, commerce, and scientific uses. GPS also provides a precise time reference used in many applications including scientific study of earthquakes, and synchronization of telecommunications networks.

GPS Advantages -

• Extremely accurate 3-D location information, latitude, longitude, altitude, velocity and precise time
• Uses WGS84 - a worldwide grid that can be converted to any local coordinate grid or map projection, i.e. State plane northing, easting and elevation
• Can be operated over extremely long distances without the need for 'line of sight'
• All-weather 24 hour operating ability

GPS Applications -

• Navigation services
• Mapping – Utilities, industries, municipalities
• Elevations and topographic maps, facility maps and databases
• Geographical Information Systems – Base maps for government and industry
• Precision farming
• Geodetic surveys for precise sub-centimeter positional tolerance
• Distribution of precise time
• Machine control for earthmoving, mining and agriculture
• Land surveys
• Hydrographic surveys

Links -

http://tycho.usno.navy.mil/gpsinfo.html
http://www.colorado.Edu/geography/gcraft/notes/gps/gps_f.html
http://www.leica-geosystems.com/