Communication system for vehicles

• US 5,751,227 A
• Filed: 06/24/1997
• Issued: 05/12/1998
• Est. Priority Date: 12/22/1994
• Status: Expired due to Term

• Current Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Original Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Inventors: Kato, Taisei, Yamashita, Mutsushi, Matsumoto, Manabu, Yoshida, Ichiro, Kago, Yoshiyuki, Ando, Toshihide
• Primary Examiner(s): Hofsass, Jeffery
• Assistant Examiner(s): Edwards, Jr., Timothy
• Application Number:
  US08/881,121
• Time in Patent Office: 322 Days
• Field of Search: 340/917, 340/928, 340/933, 340/943, 340/907, 343/700 MS, 343/711, 701/117, 701/118, 701/119, 455/107, 455/121, 455/193.1
• US Class Current: 340/928
• CPC Class Codes: G07B 15/063 using wireless information transmission between the vehicle and a fixed station identification of vehicles G08G

Abstract

A communication system for vehicles, which obtains exact communication processing with responders mounted on vehicles running on a road having a plurality of traffic lanes, is disclosed. An expressway has three traffic lanes. A gantry is disposed in a specified position on the expressway. On the gantry are disposed antenna units to counter the traffic lanes respectively. The antenna units are provided with communication areas by means of a pair of antenna elements respectively. The antenna element is composed of a microstrip array antenna disposed with eight pieces of patches laid out in two rows with four pieces in each row. The antenna units controls communication processing to communicate with vehicles adjoining each other. When response signals are sent from a vehicle mounted responder, the vehicle mounted responder is fixed and communication processing for toll collection is performed. As a result, communication processing with responders mounted on vehicles respectively which are running in the respective traffic lanes can exactly be performed.

Claims

1. A communication system for vehicles, said system comprising:

an antenna unit disposed over a road for setting a communication area by operating at a specified oscillation frequency;

an antenna element provided within the antenna unit, said antenna element including a center patch and an end patch, a transmission line connecting the center patch and the end patch and a power supply terminal connected to the transmission line, an impedance of said end patch as seen from said power supply terminal being higher than an impedance of said center patch as seen from said power supply terminal, for sending an interrogatory signal to a vehicle; and

a communication controlling means provided within the antenna unit for controlling transmission and receipt of signals at the antenna unit.

2. A communication system for vehicles according to claim 1, wherein the number and layout of the patches are determined according to a range of the communication area.

3. A communication system for vehicles according to claim 1, wherein the antenna unit comprises a first antenna element setting a communicable area beneath a part where the antenna unit is disposed, and a second antenna element setting a communicable area on a side farther than the communicable area of the first antenna element.

4. A communication system for vehicles according to claim 1, wherein the antenna elements comprises a direction adjusting means for adjusting a setting direction of the communication area.

5. A communication system for vehicles according to claim 1, wherein the antenna unit is provided for plurality over the road, and transmission frequency and transmission timing thereof differ from each other between adjoining antenna units.

6. A communication system for vehicles according to claim 1, wherein the antenna element is composed of a microstrip antenna.

7. A communication system for vehicles according to claim 1, wherein the antenna unit is disposed on a toll road and the communication system is so constructed as to exchange toll collection data necessary for traffic therethrough.

8. A communication system for vehicles according to claim 1, wherein the communication area has a length dimension approximately as much as or less than a length dimension of a vehicle.

9. A communication system for vehicles according to claim 1, further comprising:

a gantry disposed over said road, said antenna unit being disposed on said gantry;

wherein a communication area covered by said antenna unit includes a main lobe having a portion disposed in a path of a communicable portion of said vehicle and a side lobe disposed apart from said path of said communicable portion of said vehicle.

10. A communication system for vehicles according to claim 1, wherein said end part includes at least one patch.

11. A communication system for vehicles according to claim 1, wherein said end part has a communication area having a portion disposed in a path of said vehicle.

12. A communication system for vehicles according to claim 1, wherein said end part is connected to said power supply route independently of said central part.

13. A communication system for vehicles according to claim 1, wherein said communication controlling means is further for controlling transmission and receipt of signals at the antenna unit at least partially via said end part.

14. A communication system for vehicles according to claim 1, further comprising:

at least one additional center patch, said center patch and said at least one center patch being electrically connected to one another by a first portion of said transmission line; and

at least one additional end patch, said end patch and said at least one additional end patch each being connected to a respective one of said center patch and said at least one additional center patch by a second portion of said transmission line.

15. A communication system for vehicles according to claim 14, wherein an impedance of said second portion of said transmission line is higher than an impedance of said first portion of said transmission line.

16. A communication system for vehicles according to claim 1, further comprising a vehicle mounted responder mounted on the vehicle for transmitting a response signal by modulating and reflecting unmodulated carrier waves received following the receipt of the interrogatory signal.

17. A communication system for vehicles according to claim 16, wherein:

the communication controlling means is so constructed that the plurality of antenna units repetitively output pilot interrogatory signals with a specified time interval, and that the antenna unit received a pilot response signal from a certain vehicle mounted responder of all the plurality of antenna units subsequently transmits the interrogatory signal to communicate with the certain vehicle mounted responder; and

the vehicle mounted responder comprises a vehicle mounted response controlling means for outputting the pilot response signal to counter the pilot interrogatory signal upon receipt thereof and transmits the response signal in response to the interrogatory signal subsequently received.

18. A communication system for vehicles according to claim 17, wherein the vehicle mounted response controlling means transmits the response signal with a timing of a time slot selected at random from among a plurality of time slots when the vehicle mounted responder receives the pilot interrogatory signal.

19. A communication system for vehicles, said system comprising:

an antenna unit disposed over a road for setting a communication area by operating at a specified oscillation frequency;

an antenna element provided within the antenna unit, said antenna element including a center patch and an end patch, a transmission line connecting the center patch and the end patch and a power supply terminal connected to the transmission line, an impedance of said end patch as seen from said power supply terminal being different from an impedance of said center patch as seen from said power supply terminal, for sending an interrogatory signal to a vehicle, a portion of said interrogatory signal sent from said center patch being greater than a portion of said interrogatory signal sent from said end patch;

a communication controlling means provided within the antenna unit for controlling transmission and receipt of signals at the antenna unit;

wherein a communication area covered by said antenna unit includes a main lobe disposed at a position to be communicable with said vehicle and a side lobe disposed at a position where it is not communicable with said vehicle.

20. A communication system for vehicles according to claim 19, further comprising:

at least one additional center patch, said center patch and said at least one center patch being electrically connected to one another by a first portion of said transmission line; and

at least one additional end patch, said end patch and said at least one additional end patch each being connected to a respective one of said center patch and said at least one additional center patch by a second portion of said transmission line.

21. A communication system for vehicles according to claim 20, wherein an impedance of said second portion of said transmission line is higher than an impedance of said first portion of said transmission line.