Traffic preemption system signal validation method

• US 7,307,547 B2
• Filed: 06/01/2005
• Issued: 12/11/2007
• Est. Priority Date: 06/01/2005
• Status: Active Grant

• Current Assignee: Global Traffic Technologies LLC (Vontier Corp.)
• Original Assignee: Global Traffic Technologies LLC (Vontier Corp.)
• Inventors: Schwartz, Mark A.
• Primary Examiner(s): La; Anh V.
• Application Number:
  US11/142,013
• Publication Number:
  US 20060273924A1
• Time in Patent Office: 923 Days
• Field of Search: 340/907, 340/906, 340/908, 340/436, 340/909, 340/910, 340/911, 340/924, 340/902, 340/991, 340/992, 340/993, 701/201, 701/213, 701/202, 701/207, 701/208, 701/117
• US Class Current: 340/907
• CPC Class Codes: G08G 1/087 Override of traffic control, e.g. by signal transmitted by an emergency vehicle

Abstract

A secure optical-communication traffic-preemption system and method is provided that securely communicates an identification code from an optical emitter to a traffic location. The optical emitter transmits light pulses that represent an encrypted code that is an encryption using a time-varying encryption key of at least an identification code. An optical detector situated at a traffic location receives the transmitted light pulses. Validation, including decryption using a time-varying decryption key, is attempted for the encrypted identification code represented within the received light pulses. In response to validating the included identification code, a traffic-preemption command is generated for a traffic light at the traffic location.

Claims

1. A secure optical-communication traffic-preemption system, comprising;

an optical emmitter adapted to transmit light pulses that represent an encrypted code that is an encryption using a time-varying encryption key of at least an identification code; and

a traffic light circuit having

an optical detector located at a traffic location and adapted to receive the transmitted light pulses, and

a decoding circuit adapted to respond to the received light pulses by attempting to validate the included identification code and, in response to validating the included identification code, generate a traffic-preemption command for a traffic light at the traffic location.

2. The traffic-preemption system of claim 1, wherein the decoding circuit is further adapted to use a decryption key to recover the identification code.

3. The traffic-preemption system of claim 1, wherein the encrypted code is a function of a pseudo-random sequence generated from the time-varying encryption key.

4. The traffic-preemption system of claim 3, wherein the light pules further represent a position in a repeating cycle of the pseudo-random sequence.

5. The traffic-preemption system of claim 3, wherein the time-varying encryption key changes as a function of a natural parameter.

6. The traffic-preemption system of claim 5, wherein the natural parameter is time-based.

7. The traffic-preemption system of claim 5, wherein the natural parameter is algorithmically-based.

8. The traffic-preemption system of claim 1, wherein the light pulses further represent the identification code.

9. The traffic-preemption system of claim 1, wherein the decoding circuit is adapted to use a look-up table to validate the identification code.

10. The traffic-preemption system of claim 1, wherein the decoding circuit is adapted to log the success and failure of the attempt to validate the included identification code.

11. The traffic-preemption system of claim 1, wherein a key is manually implemented based on a recently-issued administration function, and the decoding circuit is adapted to use decryption based on the key to recover the identification code.

12. The traffic-preemption system of claim 1, wherein a key is automatically implemented by at least the decoding circuit.

13. The traffic-preemption system of claim 1, further including an encoding circuit, communicatively coupled to and providing the encrypted code to the optical emitter, wherein the time-varying encryption key is a time-varying symmetric key that is

manually implemented by the encoding circuit based on a recently-issued administration function, and

automatically implemented by and used by the decoding circuit to recover the identification code.

14. The traffic-preemption system of claim 13, wherein the time-varying symmetric key is automatically implemented by and used by the decoding circuit both to recover the identification code and to alter a manner in which the decoding circuit recovers the identification code.

15. The traffic-preemption system of claim 1, wherein the decoding circuit is further adapted to recover the identification code using two values for a decryption key that correspond to two successive values of the time-varying encryption key.

16. The traffic-preemption system of claim 1, wherein the optical emitter is mounted to a vehicle and the identification code is a vehicle identification code associated with the vehicle.

17. A detection arrangement of an optical-communication traffic-preemption system, comprising:

an optical detector located at a traffic location and adapted to receive transmitted light pulses from an optical emitter, the transmitted light pulses including an operation identification code that is encrypted using a time-varying encryption key; and

a validation circuit coupled to the optical detector, the validation circuit adapted to store a time-varying decryption key, decrypt using the time-varying decryption key the operation identification code that is encrypted, and attempt to validate the operation identification code.

18. The detection arrangement of claim 17, wherein the operation identification code is a vehicle identification code and the validation circuit is further adapted to generate a phase request for traffic preemption at the traffic location in response to validating the vehicle identification code.

19. The detection arrangement of claim 17, wherein the operation identification code is a key download command and the validation circuit is further adapted to update the time-varying decryption key stored in the validation circuit in response to validating the key download command.

20. The detection arrangement of claim 17, wherein the validation circuit is further adapted to update the time-varying decryption key by one of wired telephone connection, wireless telephone connection, wired internet access, and wireless internet access.

21. A method for securely communicating an operation identification code to a traffic location in an optical-communication traffic-preemption system, comprising:

encrypting the operation identification code using a time-varying encryption key;

transmitting light pulses from an optical emitter, wherein the light pulses represent the operation identification code that is encrypted;

receiving the light pulses at an optical detector situated at the traffic location;

decrypting using a time-varying decryption key the received operation identification code that is encrypted; and

validating the operation identification code that is decrypted.

22. The method of claim 21, further comprising issuing a preemption command for a traffic light at the traffic location in response to the validation of the operation identification code that is decrypted.

23. The method of claim 22, wherein the operation identification code includes a vehicle identification code associated with a vehicle to which the optical emitter is mounted.

24. The method of claim 21, wherein the operation identification code is key download command and the time-varying decryption key is updated in response to the validation of the operation identification code that is decrypted.

25. The method of claim 21, further comprising logging the success and failure of the validation of the operation identification code that is decrypted.

26. A secure optical-communication traffic-preemption system, comprising:

means for encrypting an operation identification code using a time-varying encryption key;

means for transmitting light pulses from an optical emitter, wherein the light pulses represent the operation identification code that is encrypted;

means for receiving the light pulses at an optical detector situated at the traffic location;

means for decrypting using a time-varying decryption key the received operation identification code that is encrypted; and

means for validating the operation identification code that is decrypted.