Wireless roadway monitoring system
First Claim
1. A wireless roadway sensing apparatus comprising:
- a sensor configured for installation beneath a roadway surface, the sensor, when so installed, sensing at least one of (i) a vehicle on the roadway passing the sensor, (ii) an average speed of vehicles on the roadway passing the sensor, (iii) types of vehicles on the roadway passing the sensor, (iv) water on the roadway, and (v) ice on the roadway; and
a wireless transmitter, in communication with the sensor, for periodically broadcasting sensed information according to a receiverless protocol comprising a sparse time-division-multiple-access, randomized-time-of-transmission protocol.
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Accused Products
Abstract
A wireless, in-road traffic sensor system using sensors that are small, low-cost, and rugged. The sensors may be capable of measuring the speed of passing vehicles, identifying the type of passing vehicle and measuring information about roadway conditions, e.g., wet or icy. The sensor includes a wireless transmitter and may be configured for installation beneath a roadway surface. The sensors may be configured as a traffic sensor system including distributed sensors across a roadway system, concentrators for receiving the sensor broadcasts and a central computer for accumulating and organizing the sensed information. The sensed information may also be made available responsive to user requests via the Web through such reports as traffic delays, alternate route planning and travel time estimates. Alternatively, the sensed information may also be used to control traffic through a traffic control means, such as a traffic signal.
128 Citations
58 Claims
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1. A wireless roadway sensing apparatus comprising:
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a sensor configured for installation beneath a roadway surface, the sensor, when so installed, sensing at least one of (i) a vehicle on the roadway passing the sensor, (ii) an average speed of vehicles on the roadway passing the sensor, (iii) types of vehicles on the roadway passing the sensor, (iv) water on the roadway, and (v) ice on the roadway; and
a wireless transmitter, in communication with the sensor, for periodically broadcasting sensed information according to a receiverless protocol comprising a sparse time-division-multiple-access, randomized-time-of-transmission protocol. - View Dependent Claims (2, 3, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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4. The apparatus of 2 further comprising circuitry for adjusting the magnetic-field sensor.
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26. A method for sensing roadway information comprising the steps of:
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(a) installing a sensor beneath a roadway surface, the sensor, when so installed, sensing at least one of (i) vehicles on the roadway passing the sensor, (ii) an average speed of vehicles on the roadway passing the sensor, (iii) types of vehicles on the roadway passing the sensor, (iv) water on the roadway, and (v) ice on the roadway; and
(b) transmitting sensed information by means of periodic wireless broadcasts broadcasting sensed information according to a receiverless protocol that comprises a sparse time-division-multiple-access protocol. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39)
(a) measuring a time difference between a vehicle being sensed at one sensor and the same vehicle being sensed at the other sensor; and
(b) determining the vehicle speed by dividing the baseline separation distance by the measured time difference.
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32. The method of claim 26 further comprising the step of counting a number of vehicles on the roadway passing the sensor.
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33. The method of claim 26 wherein the step of transmitting sensed information comprises transmitting a narrowband signal.
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34. The method of claim 33 wherein the narrowband signal is a frequency-shift-keying signal.
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35. The method of claim 26 wherein the step of transmitting sensed information comprises transmitting a spread-spectrum signal.
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36. The method of claim 26 wherein the step of transmitting sensed information comprises transmitting a radio-frequency signal within a frequency band spanning 300 MHz to 3,000 MHz.
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37. The method of claim 36 wherein the step of transmitting sensed information comprises transmitting a radio-frequency signal within a frequency band spanning 902 MHz to 928 MHz.
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38. The method of claim 26 wherein the sensor senses water through measurement of at least one of capacitance, permittivity, and conductivity.
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39. The method of claim 26 wherein vehicles on the roadway passing the sensor are detected by means of an acoustic sensor sensing pressure variations.
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40. A wireless roadway sensing apparatus comprising:
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a sensor configured to sense at least one roadway condition; and
a wireless transmitter in communication with the sensor, the wireless transmitter being responsive to the sensor and periodically broadcasting sensed information on a communication channel by means of a randomized multiplexing scheme, the multiplexing scheme allowing the channel to be shared with other sensors broadcasting in accordance with the scheme. - View Dependent Claims (41, 42, 43, 44, 45)
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46. A method for sensing roadway information comprising the steps of:
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(a) sensing at least one roadway condition; and
(b) transmitting sensed information on a communication channel through periodic wireless broadcasts by means of a randomized multiplexing scheme, the multiplexing scheme allowing the channel to be shared with other sensors broadcasting in accordance with the scheme. - View Dependent Claims (47, 48, 49, 50, 51, 52, 53)
(c) receiving transmitted sensed information at a server computer connected to the Internet; and
(d) providing requested information in response to Internet-based requests relating to sensed information.
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53. The method of claim 52 wherein step (c) comprises:
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(c-1) receiving transmitted sensed information at a concentrator; and
(c-2) transmitting received information to a central computer comprising a server connected to the Internet.
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54. A method for controlling traffic comprising the steps of:
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(a) installing a sensor beneath a roadway surface, the sensor, when so installed, sensing a roadway condition;
(b) transmitting information relevant to the sensed condition through periodic wireless broadcasts on a communication channel according to a receiverless protocol by means of a randomized multiplexing scheme comprising a sparse time-division-multiple-access protocol; and
(c) actuating, in accordance with the broadcasts, a traffic-controlling device responsive thereto. - View Dependent Claims (55, 56, 57, 58)
(a) installing a plurality of additional sensors beneath the roadway surface at different locations, the sensors, when so installed, sensing the roadway condition and transmitting information relevant to the sensed condition through periodic wireless broadcasts; and
(b) receiving the broadcasts at a concentrator, the traffic controlling device being responsive to the concentrator.
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Specification