Performance of UWB position estimation based on time-of-arrival measurements

The paper reports on the development of a low-cost device for low data rate communications with tracking and positioning capabilities. We investigate the performance of two different position estimation methods based on the estimate of the time-of-arrival (TOA) of the UWB signal at a set of receivers/sensors. The performance evaluation is performed in terms of the root mean-squared (RMS) error of the position coordinates estimation and the failure rate. We first study the direct-calculation method which gives exact solutions of a set of simultaneous equations. We then study one of the classical nonlinear optimization techniques, the Davidon-Fletcher-Powell (DFP) quasi-Newton algorithm. Both the direct-calculation method and the nonlinear optimization algorithms do not require any knowledge of the TOA estimation error variance or distribution. This advantage would be attractive for practical applications.