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(Ground Penetrating Radar) A UWB-based technology that locates objects buried underground. It is used to locate buried lines, storage tanks, pipes and conduits as well as to determine the structural integrity of the ground underneath a road or runway. It is also used in archaeological exploration. GPR imaging is done by fire and rescue services, law enforcement agencies and various commercial and scientific organizations. See UWB.

A GPR Image
Leesburg, Virginia-based GeoModel is an underground locating service that uses GPR to find buried objects. This image, obtained using a 400 MHz antenna, shows where underground tanks are located at a service station in Orlando, Florida. (Image courtesy of GeoModel, Inc.,


(Ultra-WideBand) A wireless technology that uses less power and provides higher speed than Wi-Fi and first-generation Bluetooth products. Governed by the WiMedia Alliance, UWB is geared for home theater video, auto safety and navigation, medical imaging and security surveillance.

Pulse Radio
Unlike other radio transmission, UWB does not use a continuous carrier frequency. It transmits extremely short pulses, and the durations between pulses use no power. One method transmits the pulses in continuously varying time slots based on a pseudo-random number sequence like CDMA. The other divides the spectrum into smaller frequency bands that can be added and dropped as necessary.

UWB Sees Through Walls
Because UWB can transmit through materials that would bounce other radio signals, it is also used to pinpoint objects behind barriers or buried underground. First invented by Gerald Ross at Sperry Rand Corporation in the late 1960s, UWB has been used by the military for various radar systems. In 1998, the FCC allowed UWB for police work and fire fighting. In 2002, it sanctioned the technology at considerably lower power for commercial use. See WiMedia Alliance, 802.15 and GPR.

              Max.   Freq.   Indoor
  Wireless   Speed   Range   Range
  Type       (Mbps)  (GHz)   (ft.)

  UWB         480   3.1-10.6   33

  BT 1.2       1     2.4      330
  BT 2.0       3     2.4      330

  802.11b     11     2.4      150
  802.11g     54     2.4      170
  802.11a     54     5         95
  802.11n    600     2.4/5    230
  802.11ac  6770     5        230

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