Sensor systems for estimating field

In a sensor array for detecting and estimating the progression of an item of interest, the sensor array comprising a plurality of sensors and means for determining sensor reading at predetermined intervals, a method for estimating a distribution function for an item of interest, the method comprising the steps of:

• determining at each interval a plurality of functions representing possible distributions of the item of interest by means of a Gaussian process,
• predicting the progression of each such function at a subsequent sampling instant, using a system model for the item of interest,
• determining a likelihood value for each function at the subsequent sampling instant, and determining a revised plurality of functions with associated likelihood values, and
• repeating said predicting and determining steps.