Method and device for determining the distance between a radio beacon and an onboard unit
First Claim
1. A method for determining a distance between a radio beacon and an onboard unit passing the radio beacon in a road toll system, wherein at least one of the radio beacon and the onboard unit emits a signal with a known curve of its frequency over time, the method comprising:
- receiving the signal by the other of the radio beacon and the onboard unit during the passing and recording the curve of the frequency of the received signal over time;
detecting a change in the recorded frequency curve exceeding a first threshold value;
determining two far regions in the recorded frequency curve lying before and after the detected change in time that show a frequency change below a second threshold value;
scaling the recorded frequency curve in such a manner that the far regions assume predetermined values; and
determining said distance from the scaled frequency curve.
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Accused Products
Abstract
The invention relates to a method for determining the distance between a radio beacon and a vehicle device passing in front of said radio beacon, in a road toll system. A signal of a frequency having a known temporal profile is emitted. Said method consists of the following steps: the signal is captured in the other component when passing and the temporal profile of the frequency is recorded in relation to the known temporal profile; a modification in the recorded frequency profile exceeding a first threshold value is detected; two distant wave zones in the frequency profile, lying temporally in front of and behind the detected modification, which displays a frequency modification below a second threshold value, are searched for; the recorded frequency profile is scaled in such a manner that the distance wave zones take the predetermined values; and said distance “a” from the scaled frequency path is determined. The invention also relates to radio beacons, installations and vehicle devices for implementing the method.
8 Citations
40 Claims
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1. A method for determining a distance between a radio beacon and an onboard unit passing the radio beacon in a road toll system, wherein at least one of the radio beacon and the onboard unit emits a signal with a known curve of its frequency over time, the method comprising:
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receiving the signal by the other of the radio beacon and the onboard unit during the passing and recording the curve of the frequency of the received signal over time; detecting a change in the recorded frequency curve exceeding a first threshold value; determining two far regions in the recorded frequency curve lying before and after the detected change in time that show a frequency change below a second threshold value; scaling the recorded frequency curve in such a manner that the far regions assume predetermined values; and determining said distance from the scaled frequency curve. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A radio beacon for a road toll system for determining a distance of a vehicle passing the radio beacon, wherein the vehicle is equipped with an onboard unit, which emits a signal with a known curve of its frequency over time comprising:
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a receiver configured to receive the signal from the passing vehicle; a memory connected to the receiver, which is configured to record a curve of the frequency of the received signal over time; a detector electrically coupled to the memory and configured to detect a change in the recorded frequency curve; a first evaluation device electrically coupled to the detector and the memory and configured to determine two far regions in the recorded frequency curve lying before and after the detected change in time that show a frequency change below a threshold value; a scaling device electrically coupled to the memory and the first evaluation device and configured to scale the recorded frequency curve in such a manner that the far regions assume predetermined values; and a second evaluation device electrically coupled to the scaling device and configured to determine the distance from the scaled frequency curve. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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33. An onboard unit for a road toll system for determining the distance from a radio beacon of the road toll system, wherein the radio beacon emits a signal with a known curve of its frequency over time comprising:
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a receiver configured to receive the signal from the radio beacon; a memory electrically coupled to the receiver configured to record the curve of the frequency of the received signal over time; a detector electrically coupled to the memory and configured to detect a change in the recorded frequency curve; a first evaluation device electrically coupled to the detector and the memory and configured to determine two far regions in the recorded frequency curve lying before and after the detected change in time that show a frequency change below a threshold value; a scaling device electrically coupled to the memory and the first evaluation device and configured to scale the recorded frequency curve in such a manner that the far regions assume predetermined values; and a second evaluation device electrically coupled to the scaling device, configured to determine the distance from the scaled frequency curve. - View Dependent Claims (34, 35, 36, 37, 38, 39, 40)
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Specification