Sensor/Actuator Calibration



Research Publications Misc
Overview Instead of using a single, highly-engineered sensor, sensor networks monitor the world through hundreds of cheap, assembly-line components. Many such devices have poor factory calibration and drift over time during use. Because sensor networks can contain thousands of such sensors and can be influenced by the environment, they should be self-calibrated after deployment. Unfortunately, pairing each sensor with an actuator to provide a known stimulus does not solve this problem because the actuators must also be calibrated. We developed a technique in which, instead, each node calibrates its sensor using the actuators of all of its neighbors. This creates an over-constrained system from which calibration coefficients can be inferred even in the face of some noise from both the sensors and actuators. We demonstrated the calibration technique on a 36 node testbed with microphones and acoustic actuators.
Publications

Kamin Whitehouse, David Culler.  "Macro-calibration in Sensor/Actuator Networks."  Mobile Networks and Applications Journal (MONET), Special Issue on Wireless Sensor Networks.  June, 2003.  ACM Press.  

Kamin Whitehouse, David Culler.  "Calibration as Parameter Estimation in Sensor Networks."  In Proceedings of ACM International Workshop on Wireless Sensor Networks and Applications (WSNA'02).  Atlanta, Georgia, September 28, 2002.  ACM Press.   (ppt)

Software The code for this calibration technique is provided as Matlab script that takes readings collected from multiple sensor/actuator pairs and derives calibration coefficients for them. The scripts implement the uniform, pairwise, and joint calibration schemes described in the paper.


Kamin Whitehouse
Computer Science Department
The University of Virginia
217 Olsson Hall
Charlottesville, Virginia 94720