An improved algorithm for UWB-bases positioning in a multi-path environment

We derive and analyze novel distributed algorithms for calculating the position of tags in a wireless ad-hoc network. The raw data for determining the tag positions stems from time-of-arrival (ToA) measurements of radio frequency (RF) pulses transmitted in between the tags. The sensor network is expected to operate indoors, i.e., the wireless channel is characterized by heavy multi-path propagation. It turns out that the probability density function (PDF) of the TOA measurement error has heavy tails due to this multi-path environment, which has a tremendous impact on the performance of the tag position calculation. We propose a novel position calculation algorithm, which utilizes the tails in the measurement error PDF and easy to implement. This is in contrast to existing approaches, which assume that the measurement error PDF is Gaussian. The novel positioning algorithm allows distributing the required calculations onto the tags and fusing TOA measurements from a large number of tags.