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UMTS – Universal Mobile Telecommunications System – A transmission system for text, digitized voice, video, and multimedia for mobile computer and phone users no matter where they are located in the world.
Universal Transverse Mercator (UTM) – A coordinate system that uses a perpendicular grid with constant linear surface distance values between each of its grid lines in all directions. Coordinates are in meters as opposed to degrees, minutes, and seconds.
uplink – (UL or U/L) the part of communication link sent to a satellite or an airborne platform from the ground.
UPS – Universal Polar Stereographic – An azimuthal projection that is used with Universal Transverse Mercator (UTM) projection systems to represent polar regions.
USGS – United States Geological Survey
USNG – U.S. National Grid – A standard to create a more favorable environment for developing location-based services within the United States and to increase the interoperability of location services appliances with printed map products by establishing a nationally consistent grid reference system as the preferred grid for National Spatial Data Infrastructure (NSDI) applications. The U.S. National Grid is based on universally defined coordinate and grid systems and can, therefore, be easily extended for use world-wide as a universal grid reference system.
UTC – See coordinated universal time.
UTM – See Universal Transverse Mercator.
VABM – Vertical Angle Benchmark – A bench mark with elevation established by vertical angle methods.
Vector map – Maps that use lines and polygons as opposed to pixels to display an image. Image resolution is sharp even when the image is displayed or printed at an enlarged perspective.
veldt – A grassland of southern Africa.
velocity made good – See VMG.
VMG – The rate of closure to a destination waypoint based upon current speed and course.
VOG – Velocity Over Ground – The speed at which the GPS unit and the person operating it are moving with respect to the earth’s surface (ignoring tidal and current activity). Same as Speed Over Ground (SOG) and ground speed.
WAAS – Wide Area Augmentation System – A GPS-based navigation and landing system that provides precision guidance to aircraft.
WAGE – Wide Area GPS Enhancement – An attempt to improve GPS accuracy by providing more accurate satellite clock and ephemeris (orbital) data to specially-equipped receivers.
wash – 1) Low or marshy ground washed by tidal waters. 2) A stretch of shallow water. 3) The dry bed of a stream (Western U.S.).
waypoint – A checkpoint; a point of reference.
WGS-84 – The primary map standard that is used for GPS.
Wide Area Augmentation System – See WAAS.
WWMX – World-Wide Media eXchange – A centralized index of digital photos, where photos are tagged by the geographic location where they were shot.