Obtaining range measurements from ambient noise cross-correlations for the self-calibration of nodes

Abstract

The calibration of nodes in a sensor network or in a positioning system is a time-consuming process. This is especially relevant in indoor environments, where GPS signals are not available. Usually, it involves a user making transmissions either at known points, or by transmitting while moving under the area of interest. Some self-calibration methods have already been proposed for acoustic sensor network systems, that require range calculation between the nodes, to later apply a positioning algorithm. In this work, we evaluated a range mechanism based on the cross-correlation of the ambient noise naturally available indoors, so no active transmissions were required. Results from experimental tests show a minimum Mean Absolute Error (MAE) of 0.93 cm and a maximum MAE of 1.37 cm, when calculating the range between two microphones separated 18.8 cm.