The Effect of Cooperation on UWB-Based Positioning Systems Using Experimental Data
1 WiLAB, University of Bologna, Viale Risorgimento 2, 40136 Bologna, Italy
2 ENDIF and WiLAB, University of Ferrara, Via Saragat 1, 44100 Ferrara, Italy
3 Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
4 Laboratory for Information and Decision Systems (LIDS), Massachusetts Institute of Technology, Room 32-D674, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
EURASIP Journal on Advances in Signal Processing 2008, 2008:513873 doi:10.1155/2008/513873Published: 12 February 2008
Positioning systems based on ultrawide bandwidth (UWB) technology have been considered recently especially for indoor environments due to the property of UWB signals to resolve multipath and penetrate obstacles. However, line-of-sight (LoS) blockage and excess propagation delay affect ranging measurements thus drastically reducing the positioning accuracy. In this paper, we first characterize and derive models for the range estimation error and the excess delay based on measured data from real-ranging devices. These models are used in various multilateration algorithms to determine the position of the target. From measurements in a real indoor scenario, we investigate how the localization accuracy is affected by the number of beacons and by the availability of priori information about the environment and network geometry. We also examine the case where multiple targets cooperate by measuring ranges not only from the beacons but also from each other. An iterative multilateration algorithm that incorporates information gathered through cooperation is then proposed with the purpose of improving the position estimation accuracy. Using numerical results, we demonstrate the impact of cooperation on the positioning accuracy.