Vehicle detection based on magnetic declination

Geomagnetic vehicle detector (GVD) is a kind of traffic monitoring equipment based on the effect that passing vehicles disturb the geomagnetic field. Having the advantages of small size, easy installation and slight damage on the road surface, GVD is to be an attractive alternative to inductive loops. Current study on GVD is usually based on the vertical component of geomagnetic field and state machine algorithm, and is able to count traffic flow, sort vehicle type and measure vehicle speed. But the precision of these algorithms is usually affected by baseline drift and vehicle speed. A novel GVD method is presented here based on the sophisticated and widely applied magnetic declination measurement technology. With a proof test in the lab and data collected from field test, this paper proposed a vehicle detecting technology on the state machine algorithm. The results of experiment and analysis indicate that the GVD based on magnetic declination measurement is a proving traffic monitoring technology.