TinyOS-based localization system design using accelerometer

A wireless sensor network (WSN) is an energy-constrained system. Energy consumption has always been an important factor to consider in the design of WSN-based localization systems. In existing localization systems, unknown nodes send data to the sink to request for a location at a given period. However, energy is wasted if unknown nodes remain still for a long time. In this paper, we propose a method to adjust the requesting period dynamically. When people (unknown nodes) stand still, requests are infrequent. By contrast, when people are running, requests will be more frequent. To determine the motion states of unknown nodes, an accelerometer is deployed in unknown node design, and thresholds are defined from experiments to adjust the period. The energy consumption rate when different policies are taken by anchor nodes is analyzed. Results show that the introduction of an accelerometer can save energy if the low-power listening policy is adopted by anchor nodes.