Asynchronous Collaborative Localization System for Large-Capacity Sensor Networks

With the widespread application of wireless sensor networks, localization issue has attracted much attention. It is a major challenge for many sensor network tasks to locate a large number of asynchronous nodes in an unknown environment without external references. In this article, we present an asynchronous collaborative localization system (ACLS) to address the localization challenge for large-capacity sensor networks (LCSNs). ACLS exploits a hierarchical architecture, under which the wireless sensor nodes in the network are divided into parent nodes that can communicate with each other through wireless signals and child nodes that can only passively receive signals. Specific protocols and nonlinear distance estimators for this broadcast communication ranging technique are proposed. These characteristics are verified through theoretical analyses to have a strong suppression effect on local clock errors and are not sensitive to measurement noise. The simulation experiments further illustrate that the proposed ACLS can achieve high-rate and high-precision ranging and localization for asynchronous LCSN without preinstalled infrastructures.