TRT (UK) has been investigating and producing solutions for indoor positioning since 2000. Indoor positioning presents a number of key challenges which conventional technologies cannot resolve, and which TRT (UK) has successfully overcome:
Radio signals used for indoor positioning must be able to penetrate the building structure to avoid a prohibitively expensive solution requiring very dense infrastructure; this means extended range operation.
The indoor environment has multiple radio paths between any two points in the building (multipath propagation). We reliably differentiate between the different paths to determine the direct path.
The accuracy required indoors is typically greater than that needed outdoors which increases the challenges. We meet and exceed the demanding requirement of 1m in three dimensions, even through multiple walls.
The Indoor Positioning System which TRT (UK) has developed is a frequency hopped Ultra WideBand (UWB) radio operating at a staggeringly low power level of only 100 microwatts. The high bandwidth makes it possible to separate out the multipath components and hence achieve highly accurate positioning. The use of frequency hopping, as opposed to the classical narrow pulse version of UWB delivers a much greater free space range of 1Km, and hence much greater building penetration; the key benefit is increased coverage and a much simplified infrastructure making any installation much more affordable and simple to install.
The first version of the demonstration system designed for ad hoc deployment was demonstrated as part of the EUROPCOM project at the UK Fire Service College in March 2008. This trial was made by fire-fighters inside a concrete building (with no pre-installed infrastructure whatsoever). The system was used to brief, track and direct the fire fighters in a series of exercises involving searches and the recovery of injured personnel where a fire fighter had fallen through the floor – here the built in telemetry channel proved extremely useful in raising and acknowledging alarms.
The system performance has since been dramatically improved and a recording of the typical in-building performance can be viewed here. Please note this is a screenshot of the actual FH-UWB position data without any inertial aiding, map matching, tracking, smoothing or filtering.
The FH-UWB technology is strongly protected by granted patents in Europe, US and the Far East.
