Method and Devices 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 frequency curve 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 its frequency over time in relation to the known frequency curve over time, wherein the recording of the frequency curve is started when the strength of the received signal exceeds a minimum threshold and is ended when the strength of the received signal falls below the minimum threshold;
detecting a change in the recorded frequency curve exceeding a first threshold value;
determining two far regions in the 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.
1 Assignment
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Accused Products
Abstract
System and method for determining the distance between a radio beacon and a vehicle device passing in the radio beacon, in a road toll system. A signal having a known temporal profile is emitted by one of the radio beacon and vehicle device. The signal is captured in the other component during the passing of the device and the temporal profile of the frequency is recorded in relation to the known temporal profile; a modification in the recoded 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 are determined, the zones displaying a frequency modification below a second threshold value are searched for; the recorded frequency profile is scaled in such a way that the distant wave zones take the predetermined values; and the distance is determined from the scaled frequency profile.
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Citations
24 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 frequency curve 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 its frequency over time in relation to the known frequency curve over time, wherein the recording of the frequency curve is started when the strength of the received signal exceeds a minimum threshold and is ended when the strength of the received signal falls below the minimum threshold; detecting a change in the recorded frequency curve exceeding a first threshold value; determining two far regions in the 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)
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12. 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 frequency curve over time comprising:
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a receiver configured to receive the signal of said passing vehicle; a sensor for detecting an approach of said vehicle towards the radio beacon; a memory electrically coupled to the receiver and the sensor and configured to record the known frequency curve of the received signal over time, when said sensor detects the approach of the vehicle; a detector electrically coupled to the memory and configured to detect a change in the recorded frequency curve exceeding a first threshold value; a first evaluation device electrically coupled to the detector and the memory and configured to determine two far regions in the frequency curve lying before and after the detected change that show a frequency change below a second 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 (13, 14, 15, 16, 18)
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17. (canceled)
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19. An onboard unit for a road toll system for determining a distance from a radio beacon of the road toll system, wherein the radio beacon emits a signal with a known frequency curve over time comprising:
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a receiver configured to receive the signal from the radio beacon; a sensor for detecting an approach of the onboard unit towards said radio beacon; a memory electrically coupled to the receiver and the sensor and configured to record the frequency curve of the received signal over time, when said sensor detects said approach; a detector electrically coupled to the memory and configured to detect a change in the recorded frequency curve exceeding a first threshold value; a first evaluation device electrically coupled to the detector and the memory and configured to determine two far regions in the 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 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, 24)
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23. (canceled)
Specification