Method for measuring the speed of a vehicle
AssigneeValeo Schalter und Sensoren GmbH
InventorMartin Reiche
Life of this patent
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Abstract
The invention concerns a method and a device to measure the speed (v) of a vehicle relative to a road surface. To increase the accuracy of the speed measurement and in order to be able to determine the speed (v) of the vehicle independently of the diameter and the adhesion of a vehicle wheel on the road surface, the invention proposes that the speed (v) of the vehicle is measured directly on the road surface by utilizing the Doppler effect.
Claims22
A method of measuring the speed of a vehicle relative to a road surface, characterized in that the speed (v) of the vehicle is measured directly at the road surface by utilizing the Doppler effect, and an actual circumference of a wheel of the vehicle and a tire pressure of the wheel are determined from the comparison of an indirectly measured speed of the vehicle with the directly measured speed of the vehicle.
The method according to 6, characterized in that a distance between the vehicle and an object on the road toward a front of the vehicle comprising one of another vehicle, lane markings and the like is determined by means of the Doppler radar.
A method of measuring the speed of a vehicle relative to a road surface, characterized in that the speed (v) of the vehicle is measured directly at the road surface by utilizing one Doppler radar unit wherein electromagnetic waves are emitted at an angle (α) onto the road surface in front of the vehicle in the direction of travel, whereby the speed (v) of the vehicle is determined by:
- v=k(l−fS/fE) cos α, with a constant k,
- a transmit frequency fS of the electromagnetic waves emitted from the Doppler radar unit;
- and
- a receive frequency fE of the electromagnetic waves reflected from the road surface to the Doppler radar unit.
A method of measuring the speed of a vehicle relative to a road surface, characterized in that the speed (v) of the vehicle is measured directly at the road surface by utilizing the Doppler effect whereby pulse-modulated electromagnetic waves modulated in their amplitude are transmitted onto the road surface by a Doppler radar, the pulse-modulated electromagnetic waves are reflected from the road surface, the reflected pulse-modulated electromagnetic waves are received by the Doppler radar, the speed (v) of the vehicle is determined from the difference between the transmit frequency (fS) and the receive frequency (fE) and the propagation time of the pulse-modulated electromagnetic waves is determined from the time delay of the transmit pulses to the receive pulses.
A device to measure the speed (v) of a vehicle relative to a road surface, characterized in that the device possesses:
- primary means constructed as a Doppler radar to measure the speed (v) of the vehicle directly at the road surface by utilizing the Doppler effect, the Doppler radar located in the forward area of the vehicle in the direction of travel and located in such a way that the electromagnetic waves strike the road surface in the direction of travel in front of the vehicle at an angle of inclination (α);
- and
- means for determining a distance between the vehicle and an object on the road comprising one of another vehicle, lane markings and the like using the Doppler radar.
Dependencies are inferred from the claim text.