Joint TOA/AOA-based localization in wireless sensor networks

Wireless sensor network (WSN) localization has drawn attention in a broad spectrum of applications for security, disaster response, monitoring, surveillance and tactical system. The deployment of a large number of low-cost, low-power and multi-functional sensors is preferred, which provides an exceptional localization performance via cooperative communication. In this paper, we consider a cooperative localization in WSNs consisting of multiple anchor nodes (ANs) equipped with a linear antenna array of M elements, a single-antenna target and a central unit (CU). We focus on a synchronous network and all the channels are supposed to be frequency-flat. Our objective is to evaluate the performance of localization technique for the target's position that jointly exploits both Time-of-Arrival (TOA) and Angle-of-Arrival (AOA) measurements. We derive the Cramér-Rao bound (CRB) for a joint TOA/AOA-based localization. Additionally, for the performance comparison, the CRBs of solely TOA- and AOA-based localizations are also derived. By numerical results, our analysis is verified and it is observed that the joint TOA/AOA-based localization has a superior performance than either TOA- or AOA-based localization.