Granted Patent B2

US 7,426,450 · App. 10/754,217 · Granted Sep 16, 2008

Abstract

Claims (92)

1. A method for measuring a speed of a vehicle approaching an intersection as the vehicle passes through a field of view of a dual transducer sensor configuration, the method comprising:

receiving one or more signals at a first transducer of the dual sensor configuration, the one or more signals received at the first transducer being reflected off of or emanating from a vehicle as the vehicle passes through a first field of view of the first transducer;

receiving one or more signals at a second transducer of the dual transducer sensor configuration, each of the one or more signals received at the second transducer having a time delay relative to a corresponding signal received at the first transducer resulting in a series of time delays between signals received at the first transducer and signals received at the second transducer, the one or more signals received at the second transducer being reflected off of or emanating from the vehicle as the vehicle passes through a second field of view of the second transducer, wherein the second field of view at least partially overlaps with the first field of view;

performing a plurality of correlations between the one or more signals received at the first transducer and the one or more signals received at the second transducer, wherein the result is a correlation function indicating the correlation between signals received at the first transducer and signals received at the second transducer for the series of time delays;

identifying a time delay, from among the series of time delays, corresponding to a peak correlation in the correlation function;

determining the speed of the vehicle using the identified time delay and a distance between the first transducer and the second transducer;

using the determined speed to monitor the safety of the intersection;

the first transducer transmitting one or more transmitted signals into the field of view of the first transducer; and

the second transducer transmitting one or more transmitted signals into the field of view of the second transducer such that the one or more transmitted signals transmitted into the field of view of the second transducer at least partially overlap with the one or more transmitted signals transmitted into the field of view of the first transducer.

2. A method as defined in claim 1 , wherein said one or more signals received at the first transducer comprises one or more of:

a radio frequency signal;

an infrared signal;

a laser signal; and

an acoustic signal.

3. A method as defined in claim 1 , wherein receiving one or more signals at the first transceiver comprises receiving one or more signals from the vehicle or from within the vehicle.

4. A method as defined in claim 1 , wherein determining the speed of a vehicle using the identified time delay and a distance between the first transducer and the second transducer further comprises:

calculating the speed of the vehicle using a magnitude of the identified time delay;

calculating a direction of travel of the vehicle using a sign of the identified time delay.

5. A method as defined in claim 1 , wherein more than two transducers are used to provide multiple time delay measurement that can be combined to reduce measurement error.

6. The method as recited in claim 1 , wherein the dual transducer sensor configuration comprises a side fire sensor.

7. The method as recited in claim 1 , wherein

receiving one or more signals at the first transducer comprises receiving one or more reflected electromagnetic radio frequency signals; and

receiving one or more signals at the second transducer comprises receiving one or more reflected electromagnetic radio frequency signals.

8. A method for measuring a speed of a vehicle approaching an intersection as the vehicle passes through a field of view of a dual transducer sensor configuration, the method comprising:

receiving one or more signals at a first transducer of the dual transducer sensor configuration, the one or more signals received at the first transducer being reflected off of or emanating from a vehicle as the vehicle passes through the field of view of the first transducer;

receiving one or more signals at a second transducer of the dual transducer sensor configuration, each of the one or more signals received at the second transducer having a time delay relative to a corresponding signals received at the first transducer resulting in a series of time delays between signals received at the first transducer and signals received at the second transducer, the one or more signals received at the second transducer being reflected off of or emanating from the vehicle as the vehicle passes through the field of view of the second transducer;

performing a plurality of correlations between the one or more signals received at the first transducer and the one or more signals received at the second transducer, wherein the result is a correlation function indicating the correlation between signals received at the first transducer and signals received at the second transducer for the series of time delays;

identifying a time delay, from among the series of time delays, corresponding to a peak correlation in the correlation function;

determining the speed of the vehicle using the identified time delay and a distance between the first transducer and the second transducer;

using the determined speed to monitor the safety of the intersection

the first transducer transmitting one or more transmitted signals into the field of view of the first transducer; and

the second transducer transmitting one or more transmitted signals into the field of view of the second transducer such that the one or more transmitted signals transmitted into the field of view of the second transducer at least partially overlap with the one or more transmitted signals transmitted into the field of view of the first transducer.

9. A method as defined in claim 8 , wherein said one or more signals received at the first transducer comprises one or more of:

a radio frequency signal;

an infrared signal;

a laser signal; and

an acoustic signal.

10. A method as defined in claim 8 , wherein receiving one or more signals at the first transceiver comprises receiving one or more signals from the vehicle or from within the vehicle.

11. A method as defined in claim 8 , wherein determining the speed of a vehicle using the identified time delay and a distance between the first transducer and the second transducer further comprises:

calculating the speed of the vehicle using a magnitude of the identified time delay; and

calculating a direction of travel of the vehicle using a sign of the identified time delay.

12. A method as defined in claim 8 , wherein more than two transducers are used to provide multiple time delay measurements that can be combined to reduce measurement error.

13. The method as recited in claim 8 , wherein the dual transducer sensor configuration comprises a side fire sensor.

14. The method as recited in claim 8 , wherein receiving one or more signals at the first transducer comprises:

receiving one or more reflected electromagnetic radio frequency signals; and

receiving one or more signals at the second transducer comprises receiving one or more reflected electromagnetic radio frequency signals.

15. A method for measuring a speed of a vehicle on a roadway as the vehicle passes through a field of view of a dual transducer sensor configuration, the method comprising:

receiving one or more signals at a first transducer of the dual transducer sensor configuration, the one or more signals received at the first transducer being reflected off of or emanating from a vehicle as the vehicle passes through the field of view of the first transducer;

receiving one or more signals at a second transducer of the dual transducer sensor configuration, each of the one or more signals received at the second transducer having a time delay relative to a corresponding signal received at the first transducer resulting in a series of time delays between signals received at the first transducer and signals received at the second transducer, the one or more signals received at the second transducer being reflected off of or emanating from the vehicle as the vehicle passes through the field of view of the second transducer, wherein the field of view of the second transducer at least partially overlaps with the field of view of the first transducer;

performing a plurality of correlations between the one or more signals received at the first transducer and the one or more signals received at the second transducer, wherein the result is a correlation function indicating the correlation between signals received at the first transducer and signals received at the second transducer for the series of time delays;

identifying a time delay, from among the series of time delays, corresponding to a peak correlation in the correlation function;

determining the speed of the vehicle using the identified time delay and a distance between the first transducer and the second transducer;

using the determined speed to monitor traffic on the roadway

the first transducer transmitting one or more transmitted signals into the field of view of the first transducer; and

the second transducer transmitting one or more transmitted signals into the field of view of the second transducer such that the one or more transmitted signals transmitted into the field of view of the second transducer at least partially overlap with the one or more transmitted signals transmitted into the a field of view of the first transducer.

16. A method as defined in claim 15 , wherein said one or more signals received at the first transducer comprises one or more of:

a radio frequency signal;

an infrared signal;

a laser signal; and

an acoustic signal.

17. A method as defined in claim 15 , wherein receiving one or more signals at the first transceiver comprises receiving one or more signals from the vehicle or from within the vehicle.

18. A method as defined in claim 15 , wherein determining the speed of a vehicle using the identified time delay and a distance between the first transducer and the second transducer further comprises:

calculating the speed of the vehicle using a magnitude of the identified time delay;

calculating a direction of travel of the vehicle using a sign of the identified time delay.

19. A method as defined in claim 15 , wherein more than two transducers are used to provide multiple time delay measurements that can be combined to reduce measurement error.

20. The method as recited in claim 15 , wherein the dual transducer sensor configuration comprises a side fire sensor.

21. The method as recited in claim 15 , wherein

receiving one or more signals at the first transducer comprises receiving one or more reflected electromagnetic radio frequency signals; and

receiving one or more signals at the second transducer comprises receiving one or more reflected electromagnetic radio frequency signals.

22. A method for measuring a speed of a vehicle on a roadway as the vehicle passes through a field of view of a dual transducer sensor configuration, the method comprising:

receiving one or more signals at a first transducer of the dual transducer sensor configuration, the one or more signals received at the first transducer being reflected off of or emanating from a vehicle as the vehicle passes through the field of view of the first transducer;

receiving one or more signals at a second transducer of the dual transducer sensor configuration, each of the one or more signals received at the second transducer having a time delay relative to a corresponding signal received at the first transducer resulting in a series of time delays between signals received at the first transducer and signals received at the second transducer, the one or more signals received at the second transducer being reflected off of or emanating from the vehicle as the vehicle passes through the field of view of the second transducer;

performing a plurality of correlations between the one or more signals received at the first transducer and the one or more signals received at the second transducer, wherein the result is a correlation function indicating the correlation between signals received at the first transducer and signals received at the second transducer for the series of time delays;

identifying a time delay, from among the series of time delays, corresponding to a peak correlation in the correlation function;

determining the speed of the vehicle using the identified time delay and a distance between the first transducer and the second transducer;

using the determined speed to monitor traffic on the roadway;

the first transducer transmitting one or more transmitted signals into the field of view of the first transducer; and

the second transducer transmitting one or more transmitted signals into the field of view of the second transducer such that the one or more transmitted signals transmitted into the field of view of the second transducer at least partially overlap with the one or more transmitted signals transmitted into the field of view of the first transducer.

23. A method as defined in claim 22 , wherein said one or more signals received at the first transducer comprises one or more of:

a radio frequency signal;

an infrared signal;

a laser signal; and

an acoustic signal.

24. A method as defined in claim 22 , wherein receiving one or more signals at the first transceiver comprises receiving one or more signals from the vehicle or from within the vehicle.

25. A method as defined in claim 22 , wherein determining the speed of a vehicle using the identified time delay and a distance between the first transducer and the second transducer further comprises:

calculating the speed of the vehicle using a magnitude of the identified time delay; and

calculating a direction of travel of the vehicle using a sign of the identified time delay.

26. A method as defined in claim 22 , wherein more than two transducers are used to provide multiple delay measurements that can be combined to reduce measurement error.

27. The method as recited in claim 22 , wherein the dual transducer sensor configuration comprises a side fire sensor.

28. The method as recited in claim 22 , wherein receiving one or more signals at the first transducer comprises:

receiving one or more reflected electromagnetic radio frequency signals; and

receiving one or more signals at the second transducer receiving one or more reflected electromagnetic radio frequency signals.

Assignments (10)