A Magnetic Distance Sensor with High Precision

Abstract

A magnetic distance sensor working at very low frequency has been developed to measure distances up to 1 m. The principle is similar to that of the 3-D magnetic tracker, but the system is optimized to minimize the error in distance for static measurements. The system is not affected by conductive objects. The uncertainty caused by noise and interference is below 2 mm, even in a noisy environment. The measurement time of 3 min can be decreased to 1 min, depending on the amplitude of the interferences and the required accuracy. After applying corrections, systematic error of 5 mm was achieved by using a calibration model. The system is scalable up to 20 m range.