Enhanced 3D localisation accuracy of body-mounted miniature antennas using ultra-wideband technology in line-of-sight scenarios

This study presents experimental investigations on high-precision localisation methods of body-worn miniature antennas using ultra-wideband (UWB) technology in line-of-sight conditions. Time of arrival data fusion and peak detection techniques are implemented to estimate the three-dimensional (3D) location of the transmitting tags in terms of x, y, z Cartesian coordinates. Several pseudo-dynamic experiments have been performed by moving the tag antenna in various directions and the precision with which these slight movements could be resolved has been presented. Some more complex localisation experiments have also been undertaken, which involved the tracking of two transmitter tags simultaneously. Excellent 3D localisation accuracy in the range of 1-4 cm has been achieved in various experiment settings. A novel approach for achieving subcentimetre 3D localisation accuracy from UWB technology has been proposed and demonstrated successfully. In this approach, the phase centre information of the antennas in a UWB localisation system is utilised in position estimation to drastically improve the accuracy of the localisation measurements to millimetre levels. By using this technique, the average localisation error has been reduced by 86, 31, and 72% for the x-, y-, and z-axis coordinates, respectively.Published versio

Ultra Wideband Wearable Sensors for Motion Tracking Applications

The increasing interest and advancements in wearable electronics, biomedical applications and digital signal processing techniques have led to the unceasing progress and research in novel implementations of wireless communications technology. Human motion tracking and localisation are some of the numerous promising applications that have emerged from this interest. Ultra-wideband (UWB) technology is particularly seen as a very attractive solution for microwave-based localisation due to the fine time resolution capabilities of the UWB pulses. However, to prove the viability of utilizing UWB technology for high precision localisation applications, a considerable amount of research work is still needed. The impact of the presence of the human body on localisation accuracy needs to be investigated. In addition, for guaranteeing accurate data retrieval in an impulse-radio based system, the study of pulse distortion becomes indispensable. The objective of the research work presented in this thesis is to study and carry out experimental investigations to formulate new techniques for the development of an Impulse-radio UWB sensor based localisation system for human motion tracking applications. This research work initiates a new approach for human motion tracking by making use of pulsed UWB technology which will allow the development of advanced tracking solutions with the capacity to meet the needs of professional users. Extensive experimental studies involving several ranging and three dimensional localisation investigations have been undertaken, and the potential of achieving high precision localisation using ultra-wideband technology has been demonstrated. Making use of the upper portion of the UWB band, a novel miniature antenna designed for integration in the UWB localisation system is presented and its performance has been examined. The key findings and contributions of this research work include UWB antenna characterisation for pulse based transmission, evaluation of comprehensive antenna fidelity patterns, impact of pulse fidelity on the communication performance of a UWB radio system, along with studies regarding the effect of the human body on received pulse quality and localisation accuracy. In addition, an innovative approach of making use of antenna phase centre information for improving the localisation accuracy has been presented