Highway vehicle identification system with high gain antenna

• US 5,164,732 A
• Filed: 12/05/1989
• Issued: 11/17/1992
• Est. Priority Date: 02/13/1980
• Status: Expired due to Term

• Current Assignee: Mark IV Industries Corporation
• Original Assignee: EID Electronic Identification Systems Ltd.
• Inventors: Hryciuk, Michael L., Walker, Conrad M. B., Brockelsby, William K., Gillis, Donald P.
• Primary Examiner(s): Gregory, Bernarr E.
• Application Number:
  US07/446,234
• Time in Patent Office: 1,078 Days
• Field of Search: 343/719, 343/711, 343/717, 343/770, 343/771, 343/789, 343/826, 343/827, 343/834, 343/837, 343/841, 343/847, 343/873, 342/42-45, 342/50, 342/51, 235/384, 340/505, 340/825.54, 340/933, 340/935, 340/941, 340/988
• US Class Current: 342/44
• CPC Class Codes: B61L 25/04 Indicating or recording train identities
• CPC Class Codes: B61L 25/048 using programmable tags
• CPC Class Codes: G06K 19/07 with integrated circuit chips
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G07B 15/063 using wireless information transmission between the vehicle and a fixed station identification of vehicles G08G
• CPC Class Codes: G07C 9/28 the pass enabling tracking or indicating presence
• CPC Class Codes: G08G 1/017 identifying vehicles G08G1/015, G08G1/054 take precedence

Abstract

An antenna system for mounting in a roadway comprised of an electrically lossy material. The antenna system has a reflector trough shield filled with a solid dielectric. An antenna, preferably comprised of coaxial cable, is positioned in the reflector trough, which prevents electromagnetic waves radiated by the antenna from being lost into the roadway.

Claims

1. An apparatus for communicating with a transponder carried by a vehicle moving along a multi-lane roadway, comprising:

transmitter means for producing a triggering signal;

an antenna system coupled to said transmitter means and having a portion driven by said triggering signal to produce a triggering electromagnetic field, said antenna system being embedded in said multi-lane roadway, said triggering electromagnetic field defining a localized transponder capture zone along said multi-lane roadway and substantially confined to one lane of said multi-lane roadway, said triggering electromagnetic field being radiated by said portion of said antenna system for a trigger time interval for exciting a transponder within said localized transponder capture zone;

a transponder carried by a vehicle in said one lane, said transponder being responsive to said triggering electromagnetic field for transmitting transponder response signals incorporating data related to the identity of the vehicle;

a receiver coupled to said antenna system for monitoring transponder response electrical signals from said antenna system during a transponder response time interval following said trigger time interval, said trigger time interval and said transponder response time interval defining a transponder read interval; and

means responsive to said transponder response signals for associating said received transponder response signals with said one lane of said multi-lane roadway.

2. An apparatus as defined in claim 1, wherein said transponder response time interval is of sufficient duration to allow transponder response signals incorporating the vehicle identity data to be transmitted three times.

3. An apparatus as defined in claim 1, further comprising means for modulating said triggering signal to carry coded information to be received by the transponder.

4. An apparatus as defined in claim 1, wherein said antenna system comprises a collinear antenna array having a lengthwise substantially uniform signal distribution, said collinear antenna array being aligned essentially perpendicular to a direction of travel of the vehicle along said roadway.

5. An apparatus as defined in claim 4, wherein said collinear antenna array comprises a leaky coax antenna.

6. An apparatus as defined in claim 4, further comprising a microwave circulator connected intermediate said transmitter and said collinear antenna array, said microwave circulator cyclically controlling said transponder response cycles by conducting triggering pulses from said transmitter to said collinear antenna array for radiation of said triggering signals to said transponder and by receiving transponder signals from said collinear antenna array.

7. An apparatus as defined in claim 4, wherein said antenna system further comprises a triggering loop embedded in the roadway for radiating said trigger signals.

8. An apparatus as defined in claim 1, wherein said antenna system further comprises:

a first collinear antenna array driven by said transmitting means, said first collinear antenna array radiating said trigger pulses which are to be received by an information and identify storage device carried on the vehicle; and

a second collinear antenna array for receiving signals from the information and identity storage device.

9. An apparatus as defined in claim 8, wherein said first and second collinear arrays comprise a leaky coax antenna.

10. An apparatus in accordance with claim 1 wherein said associated means responds to the receipt by said antenna system of said transponder response signals within said transponder response time following said triggering electromagnetic field signal for associating said one lane to which the triggering electromagnetic field is confined with the identity of the vehicle incorporated by said transponder response signal.

11. A fixed roadway communication station for communication with a transponder associated with a moving vehicle, comprising:

a transmitting means for transmitting interrogation signals;

a mobile transponder associated with a moving vehicle and responsive to said interrogation signals for transmitting electromagnetic radiation;

a reflector shield for positioning in a roadway for receiving said electromagnetic radiation from said mobile transponder;

a collinear antenna array positioned within said reflector shield to receive said electromagnetic radiation received by said reflector shield; and

a receiver coupled to said collinear antenna array to receive electrical energy induced in said collinear antenna array by said electromagnetic radiation.

12. A fixed roadway communication station for communication with a transponder associated with a moving vehicle as defined in claim 11, further comprising means coupling said transmitting means to said collinear antenna array.

13. An antenna system for flush and recessed mounting in a roadway for radiating electromagnetic waves to and receiving electromagnetic waves from vehicles traveling on said roadway, comprising:

an electromagnetic wave reflector having a terminal portion defining a radiation emitting aperture, said electromagnetic wave reflector being buried in a roadway with said terminal portion being positioned substantially flush with a vehicle carrying surface of said roadway; and

a radio antenna positioned within and substantially surrounded by said reflector so that said radio antenna is electrically isolated from said roadway and experiences substantially no loss of electromagnetic waves to said roadway, substantially all of said electromagnetic waves radiated from said radio antenna being radiated from said radiation emitting aperture.

14. An antenna system for flush and recessed mounting in a roadway for radiating electromagnetic waves to and receiving electromagnetic waves from vehicles traveling on said roadway as defined in claim 13, further comprising a solid dielectric positioned within said reflector between said antenna and reflector.

15. An antenna system for flush and recessed mounting in a roadway for radiating electromagnetic waves to and receiving electromagnetic waves from vehicles traveling on said roadway as defined in claim 13, wherein said radio antenna comprises a coaxial cable.

16. An antenna system for flush and recessed mounting in a roadway for radiating electromagnetic waves to and receiving electromagnetic waves from vehicles traveling on said roadway as defined in claim 13, wherein said radio antenna comprises a collinear array antenna.

17. An antenna system for flush and recessed mounting in a roadway for radiating electromagnetic waves to and receiving electromagnetic waves from vehicles traveling on said roadway as defined in claim 13, wherein said reflector comprises a substantially rectangular cross section trough.

18. An antenna system for flush and recessed mounting in a roadway for radiating electromagnetic waves to and receiving electromagnetic waves from vehicles traveling on said roadway as defined in claim 13, wherein said reflector is filled with a solid dielectric.

19. An antenna system for flush and recessed mounting in a roadway for radiating electromagnetic waves to and receiving electromagnetic waves from vehicles traveling on said roadway as defined in claim 18, wherein said radio antenna comprises a collinear array antenna.

20. An antenna system for flush and recessed mounting in a roadway for radiating electromagnetic waves to and receiving electromagnetic waves from vehicles traveling on said roadway as defined in claim 18, wherein said radio antenna comprises a coaxial cable.

21. An antenna system for flush and recessed mounting in a roadway for radiating electromagnetic waves to and receiving electromagnetic waves from vehicles traveling on said roadway as defined in claim 13, wherein said radio antenna further comprises a loop antenna.

22. A method for communicating with a moving vehicle travelling in one lane of a multi-lane roadway, comprising the steps of:

producing a first triggering electromagnetic field having a field strength defining a first transponder capture region limited to a first lane of the multi-lane roadway;

producing a first return signal by said vehicle in response to said first triggering electromagnetic field;

first monitoring a frequency of a first return information signal during a first information interval;

producing a second triggering electromagnetic field having a field strength defining a second transponder capture region limited to a second lane of multi-line roadway;

second monitoring a frequency of a second return information signal during a second information interval, different from said first information; and

determining that said one lane travelled by said vehicle is said first lane, when said first monitoring step receives said first return signal during said first information interval.