Continuous Mutual Correction from Multiple Sensors
The broad area that studies these kinds of topics is called estimation theory.  This is more a matter of statistics than of computer science, so you might want to take a look in some statistics textbooks and check out the Statistics.SE.

For instance, you might be interested in the Kalman filter.

That said, before one can devise a solution to your specific solution, we'd need a lot more information about what you know.  Do you know anything about the joint distribution of their sensing?  Do you know anything about the accuracy of each sensor (e.g., its variance)?  Are all sensors calibrated and unbiased?  Do you know anything about how the underlying physical value changes over time or the distribution it comes from?  Do some self-study of the literature, and make sure you know the answers to those before asking on Stats.SE.