| 摘要 |
A device for measuring the speed of movement of a wheeled terrestrial vehicle is characterised in that it comprises a magnetometer intended to take measurements of a magnetic field and positioned so as to be sensitive to the magnetic field variations caused by the rotation of at least one partially metallic wheel, as it is, of the vehicle and capable of delivering a corresponding signal, and means for processing said signal that are capable of establishing a frequency spectrum thereof, of determining, from said frequency spectrum, a frequency of rotation of said wheel, and of deducing therefrom, on the basis of information representative of the radius of the wheel, the speed of movement of the vehicle. Application in particular to tachometers for motor vehicles. |
