Energy-efficient localization for virtual fencing

This poster addresses the tradeoff between energy consumption and localization performance in a mobile sensor network application. It focuses on combining GPS location with more energy-efficient location sensors to bound position estimate uncertainty in order to prolong node lifetime. The focus is on an outdoor location monitoring application for tracking cattle using smart collars that contain wireless sensor nodes and GPS modules [1]. We use empirically-derived models to explore duty cycling strategies for maintaining position uncertainty within specified bounds. Specifically we explore the benefits of using short-range radio contact logging alongside GPS as an energy-inexpensive means of lowering uncertainty while the GPS is off. Results show that GPS combined with radio-contact logging is effective in extending node lifetime while meeting application-specific positioning criteria.