Abstract-A robust and accurate positioning solution is required to increase the safety in GPS-denied environments. Although there is a lot of available research in this area, little has been done for confined environments such as tunnels. Therefore, we organized a measurement campaign in a basement tunnel of Linköping university, in which we obtained ultra-wideband (UWB) complex impulse responses for line-of-sight (LOS), and three non-LOS (NLOS) scenarios. This paper is focused on timeof-arrival (TOA) ranging since this technique can provide the most accurate range estimates, which are required for rangebased positioning. We describe the measurement setup and procedure, select the threshold for TOA estimation, analyze the channel propagation parameters obtained from the power delay profile (PDP), and provide statistical model for ranging. According to our results, the rise-time should be used for NLOS identification, and the maximum excess delay should be used for NLOS error mitigation. However, the NLOS condition cannot be perfectly determined, so the distance likelihood has to be represented in a Gaussian mixture form.
Finally, the results of the measurement campaign REF , carried out in a basement tunnel of Linköping university and an iron-ore mine in Kiruna, Sweden, indicated that UWB timeof-arrival (TOA) allows very accurate ranging in line-of-sight (LOS) and non-LOS (NLOS) scenarios caused by thin obstacles.
Measurement Analysis and Channel Modeling for TOA-Based Ranging in Tunnels
IEEE Transactions on Wireless Communications, vol. 14, issue 1, pp. 456-467, Jan. 2015
Mathematics Computer Science