Cooperative localization using angle of arrival measurements in non-line-of-sight environments

Abstract

We investigate localization of a transmitting node using angle of arrival (AoA) measurements made at a geographically dispersed network of cooperating receivers with known locations. A low-complexity sequential algorithm for updating the source location estimates under line-of-sight (LOS) environments is developed. This serves as a building block for an algorithm that suppresses outliers arising due to multipath scattering and reflection in non-line-of-sight (NLOS) scenarios. Maximal likelihood (ML) location estimation requires exhaustive testing of estimates from all possible subsets of measurements. We avoid this by utilizing a randomized algorithm that approaches the ML performance at a complexity that is only quadratic in the number of measurements. The localization error is proportional in the AoA error variance and coverage area, and can be reduced by an increase in the number of estimates with a strong LOS component.