Automatic vehicle identification system capable of vehicle lane discrimination

• US 6,064,320 A
• Filed: 04/03/1998
• Issued: 05/16/2000
• Est. Priority Date: 04/04/1997
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: d'Hont, Loek, Tip, Anne
• Primary Examiner(s): Wu, Daniel J.
• Application Number:
  US09/054,952
• Time in Patent Office: 774 Days
• Field of Search: 340/928, 340/933, 340/825.54, 340/825.34, 342/42, 342/44, 342/51, 455/46, 455/47
• US Class Current: 340/933
• CPC Class Codes: G01S 13/765 with exchange of information between interrogator and responder
• CPC Class Codes: G07B 15/063 using wireless information transmission between the vehicle and a fixed station identification of vehicles G08G
• CPC Class Codes: G08G 1/017 identifying vehicles G08G1/015, G08G1/054 take precedence

Abstract

A system of vehicle identification with a first interrogator that uses a Lower SideBand (LSB) receiver to receive a modulated signal from a vehicle transponder and a second interrogator that uses an Upper SideBand (USB) receiver to receive another modulated signal. The two interrogators are adjacent to each other at a toll plaza, and operate at different carrier frequencies to force a signal frequency bandgap between communication signals in adjacent vehicle lanes.

Claims

1. A system of vehicle identification comprising:

a) a first interrogator, said first interrogator having a Lower SideBand (LSB) receiver for receiving a first modulated signal from a first vehicle transponder, said first interrogator further having a first demodulator operable to extract a first demodulated signal from the LSB of said first modulated signal; and

b) a second interrogator, said second interrogator having an Upper SideBand (USB) receiver for receiving a second modulated signal from a second vehicle transponder, said second interrogator having a second demodulator operable to extract a second demodulated signal from the USB of said second modulated signal.

2. The system of claim 1 wherein said first modulated signal has a carrier of a first frequency and said second modulated signal has a carrier of a second frequency.

3. The system of claim 2 wherein said first frequency is less than said second frequency.

4. The system of claim 1 and further comprising a third interrogator, which has a LSB receiver, said third interrogator being positioned adjacent to said second interrogator such that said second interrogator is horizontally adjacent to said first and third interrogators and positioned therebetween.

5. A system of vehicle identification comprising:

a) a first interrogator, said first interrogator having a Lower SideBand (LSB) receiver for receiving a first modulated signal from a first vehicle transponder, said first interrogator having a first demodulator operable to extract a first demodulated signal from the LSB of said first modulated signal, said first interrogator further comprising a first sideband transmitter; and

b) a second interrogator, said second interrogator having an Upper SideBand (USB) receiver for receiving a second modulated signal from a second vehicle transponder, said second interrogator having a second demodulator operable to extract a second demodulated signal from the USB of said second modulated signal, said second interrogator further comprising a second sideband transmitter, said second sideband transmitter employing the opposite sideband as was employed by the first sideband transmitter.

6. The system of claim 5 wherein said first transmitter is an LSB transmitter, and said second transmitter is a USB transmitter.