Ultra-wide band sensor networks for tracking point scatterers or relays

In this paper we investigate the possible benefits and drawbacks of using a previously proposed ldquosoftrdquo ranging algorithm for tracking moving objects in indoor scenarios. The objects considered in this work could be either passive point scatterers or active relays. A number of ultra-wide band transceivers are deployed throughout the environment, and they are used to estimate multi-path propagation delays, that constitute the input data to the tracking algorithm. The motivation behind this work is that ldquosoftrdquo ranging algorithm enables both estimation of ranging error on a measurement-by-measurement basis, and also a straight-forward approach to multiple-hypotheses testing (MHT). Thus, this type of ranging algorithm is likely to fit well into a filter-bank tracking system. Computer simulations based on Ray-tracing propagation data indicates that the proposed approach enables both more robust and also more accurate positioning than when a more conventional threshold-based technique is used for ranging.