The Minimum Number of Sensors - Interpolation of Spatial Temperature Profiles in Chilled Transports

Wireless sensor networks are an important tool for the supervision of cool chains. Previous research with a high number of measurement points revealed spatial temperature deviations of more than 5 °C in chilled transport, but the number of sensors has to be reduced to an economically useful value for use in regular transport. This paper presents a method to estimate the minimum number of sensors and to compare different sensor positioning strategies. Different methods of interpolating the temperature data of intermediate positions were applied to the experimental data from a delivery truck. The average prediction error for intermediate points was estimated as a function of the number of sensors. The Kriging method, originally developed for the interpolation of geostatistical data, produced the best results.