Drift aware wireless sensor networks

The focus of wireless sensor networks is to develop low cost sensors with sufficient computing and communication capabilities to support networked sensing applications. The emphasis on lower cost led to sensors that are less accurate and less reliable than their wired sensor counterparts. Sensors usually suffer from both random and systematic (bias) problems. Even when the sensors are properly calibrated at the time of their deployment, they develop drift in their readings leading to biased sensor measurements. The drift in this context is defined as a unidirectional long-term change in the sensor measurement. Assuming that neighboring sensors have correlated measurements and noting that the instantiation of drift in a sensor is uncorrelated with other sensors and inspired by the resemblance of registration problem in radar target tracking with the bias error problem in sensor networks we devise a novel algorithm for detecting and correcting sensors drifts and show how it improves the reliability and the effective life of the network.