Influential factors for decimetre level positioning using ultra wide band technology

The integration of wireless and satellite positioning technologies can provide positional information in both indoor and outdoor environments for various location based services and applications. Among different wireless positioning technologies, ultra wide band (UWB) adopts the time delay approach based on highly accurate clock synchronisation between transmitter and receiver antenna. High accuracy range measurement data can therefore be used to derive decimetre accuracy positions. Similar to other wireless technologies, the transmission of UWB signal is subject to interference when propagating through different media. In this paper, influential factors for the theoretical decimetre level positioning expectation of UWB are analysed with a pair of PulseOn P210 devices. Our investigations include signal attenuation in different scenarios of materials of obstruction, multipath and geometrical effects. From the analysis of field test and simulation results, we conclude that UWB can generally achieve better than 0?5 m (95% confidence level), the accuracy of which agrees with specifications of the UWB real time positioning systems (RTLS) available on the market, and field test results of a UWB RTLS conducted by Mok et al. It is essential that UWB device be set up at a higher position to avoid the influence of multipath. When setting up the UWB location system, special attention should be paid to the location of the sensors in weak geometrical strength areas, such as tunnels and narrow corridors.