An improved NLOS detection scheme for hybrid-TOA/AOA-based localization in indoor environments

Collecting location information of persons or things in sensor networks enables a variety of services and applications. For such location information, time of arrival (TOA) or angle of arrival (AOA) of radio waves is often used. Moreover, a hybrid use of them, called hybrid-TOA/AOA (HTA), has also been proposed for performance improvement. However, when the direct wave is blocked by obstacles in the non-line-of-sight (NLOS) environment, the estimation accuracy is severely deteriorated. To coordinate this problem, an iterative minimum residual (IMR) scheme has been proposed for TOA-based estimation. In the IMR scheme, the NLOS nodes are sequentially detected and eliminated, and the estimation performance is improved. However, the IMR scheme for HTA measurements has not been considered. Therefore, in this paper, we propose a new NLOS detection scheme based on IMR scheme for HTA localization and evaluate its improved performances by computer simulations.