Experimental Results from an Ultra Wideband Precision Geolocation System

Abstract

Ultra wideband waveforms can achieve extremely fine, centimeter-level range resolution because of their extremely short signal durations. With the advent of very high speed, high sensitivity, leading edge detectors, the feasibility of such systems has been demonstrated. An ultra wideband (UWB) based system has been described which enables the precision geolocation of a platform over distances of up to several kilometers (line-of-sight) and to more that one hundred meters indoors, depending upon building construction. The system uses a set of N>2, untethered UWB transceivers (Beacons) and an untethered UWB Rover to resolve time-of-flight measurement ambiguities to determine position. The UWB geolocation system is self-synchronizing, and does not require the existence of a clock distribution system and associated cabling. The system operates independently of GPS, thereby providing operation under conditions in which satellite coverage is unavailable or is blocked by obstructions or shielding (e.g., wartime operation, in buildings, urban environments, under heavy canopy, next to large obstructions such as vertical mine walls, etc.). Measurement standard deviations of less than one foot have been demonstrated for in-building operation, and less than a few inches for line-of-sight operation, using a 400 MHz bandwidth (2.5 ns duration) ultra wideband waveform.