In Situ Blind Calibration of Sensor Networks for Infrastructure Monitoring

The recent development of Internet-of-Things (IoT) technologies has enabled smaller and lower-cost sensor nodes, motivating the deployment of more flexible and scalable sensor networks for infrastructure monitoring applications. However, because these nodes tend to be affected by environmental conditions and aging, they are prone to long-term drift over years of operation; thus, they need to be recalibrated on a regular basis to ensure data accuracy. In this paper, we propose an in situ blind calibration algorithm for infrastructure monitoring sensor networks, which requires neither physical intervention nor the assumption that the sensors are measuring identical ground-truth signals. The algorithm uses a multioutput Gaussian process (MOGP) to model the spatial-temporal distribution of the measurand and drift, thus removing irrelevant short-term fluctuations and decomposing the drift from long-term trends. We evaluate the algorithm on a real-world dataset, and the results show that the proposed method can successfully calibrate a number of drifting sensors more than 20% greater than previous methods while achieving a higher drift estimation accuracy.