Non-line-of-sight Node Localization based on Semi-Definite Programming in Wireless Sensor Networks

TL;DR

This paper introduces a semi-definite programming algorithm for localizing nodes in wireless sensor networks under NLOS conditions, improving accuracy without needing to distinguish LOS from NLOS measurements.

Contribution

The paper presents a novel SDP-based localization method that effectively handles NLOS errors without requiring LOS/NLOS identification.

Findings

Achieves high localization accuracy in NLOS environments.

Does not require LOS/NLOS measurement discrimination.

Applicable to indoor UWB wireless sensor networks.

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, we propose a semi-definite programming (SDP) based node localization algorithm in NLOS environment 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 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 efficiently distinguish LOS from NLOS measurements. In this paper, an algorithm is proposed that achieves high location accuracy without the need of identifying NLOS and LOS measurement.