Low frequency magnetic flux density measurements based on navigation agents

The measurement of the low-frequency magnetic and electric fields for verifying the levels for human exposure is certainly an activity that is arousing a strong interest for its implications on the human health. On the other hand, this matter lifts interesting aspects and technical problems from a measurements point of view as well. It is not always possible to perform these measurements using a human operator, because there are situations where the environmental monitoring asks for a too large number of measurements, or the area to be monitored can be dangerous. For this reason, a research activity has been undertaken in order to carry out a measurement system based on the employment of a fleet of robot that, endowed with proper sensors, can cooperate among them and with a central unit, with the purpose to autonomously perform the environmental monitoring of structured or not structured environment. In particular, this paper describes the part of the project that deals with the development of the magnetic sensors, that will be installed on navigation robots. A low-cost smart sensor has been developed for magnetic field measurement in the frequency range 10 Hz-10 kHz, able to perform both the isotropic flux density measurement and its harmonics analysis. The logic embedded in the sensor is also able to compare the measured quantities with the reference levels for human exposure in the frequency domain, as pointed out by International Commission on Non-Ionizing Radiation Protection (ICNIRP).