Date Added: Dec 2009
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, the authors propose a Semi Definite Programming (SDP) based node localization algorithm in NLOS environment for Ultra-Wide-Band (UWB) wireless sensor networks. The positions of sensors can be estimated using the distance estimates from location-aware anchors as well as other sensors.