Detection of vehicle tracks by a three-axis magnetometer

A novel approach for target tracking enabled by a magnetic anomaly detection (MAD) system with a single three-axis magnetic sensor is demonstrated. Twelve types of three-dimensional target MAD signals at a cross road were calculated using a magnetic dipole model. Characteristic features derived from Bxy curves were used to identify the type of tracks. A nonlinear non-diagonal three-axis giant magnetoimpedance sensor (GMI) was used to validate the model, which operated in range of ± 500 mGs with a noise level below RMS 200 pT at the frequency ranging from 0.1 to10 Hz. Experimental results showed that the identification by the model was in good agreement with real tracks.