Abstract
An unknown-position sensor can be localized if there are three or more anchors making time-of-arrival (TOA) measurements of a signal from it. However, the location errors can be very large due to the fact that some of the measurements are from non-line-of-sight (NLOS) paths. In this paper, a semi-definite programming (SDP) based node localization algorithm in NLOS environments is proposed for ultra-wideband (UWB) wireless sensor networks. The positions of sensors can be estimated using the distance estimates from location-aware anchors as well as other sensors. However, in the absence of line-of-sight (LOS) paths, e.g., in indoor networks, the NLOS range estimates can be significantly biased. As a result, the NLOS error can remarkably decrease the location accuracy, and it is not easy to accurately distinguish LOS from NLOS measurements. According to the information known about the prior probabilities and distributions of the NLOS errors, three different cases are introduced and the respective localization problems are addressed. Simulation results demonstrate that this algorithm achieves high location accuracy even for the case in which NLOS and LOS measurements are not identifiable.
| Original language | English (US) |
|---|---|
| Article number | 6087384 |
| Pages (from-to) | 108-116 |
| Number of pages | 9 |
| Journal | IEEE Transactions on Wireless Communications |
| Volume | 11 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 2012 |
Bibliographical note
Funding Information:This research was supported in part by the National Natural Science Foundation of China under Grant No. 61071107, and the U. S. Office of Naval Research under Grant N00014-09-1-0342. The authors would like to thank Dr. W.-K. Ma from the Chinese University of Hong Kong, Dr. Kenneth W. K. Lui and the anonymous reviewers for their valuable suggestions concerning this work.
Keywords
- Wireless sensor networks
- non-line-of-sight (NLOS)
- semi-definite programming (SDP)
- time-of-arrival (TOA)