Vehicle speed estimation using inductive vehicle detection systems

• US 6,999,886 B2
• Filed: 09/17/2003
• Issued: 02/14/2006
• Est. Priority Date: 09/17/2002
• Status: Expired due to Fees

• Current Assignee: Inductive Signature Technologies Incorporated
• Original Assignee: Inductive Signature Technologies Incorporated
• Inventors: Hilliard, Steven R.
• Primary Examiner(s): Bui, Bryan
• Assistant Examiner(s): VO, HIEN XUAN
• Application Number:
  US10/664,319
• Publication Number:
  US 20040056778A1
• Time in Patent Office: 881 Days
• Field of Search: 702/82, 702/57, 702/96, 702/97, 702/104, 702/142, 701/119, 701/117, 340/936, 340/938, 340/939, 340/941, 340/933
• US Class Current: 702/82
• CPC Class Codes: G08G 1/042 using inductive or magnetic detectors

Abstract

A method and apparatus for communicating estimated vehicular speed and length using data obtained from a single wire-loop. The detector card connected to a single wire-loop produces a first bivalent output based on the actual measurement of a vehicle at the wire-loop sensor and synthesizes a second bivalent output to mimic the output of a two wire-loop speed trap. By simulating a second bivalent output at the detector card level, a conventional field controller is capable of estimating the vehicular speed from a single wire-loop sensor.

Claims

1. A method for communicating at least one of vehicle speed and vehicle length information gathered from a vehicle detector, said method comprising the steps of:

a) measuring at least one of a vehicle speed and a vehicle length using a vehicle detector during a first vehicle detection event;

b) constructing a first output pulse corresponding to said first vehicle detection event;

c) outputting said first output pulse on a first output channel associated with said vehicle detector;

d) inferring a second vehicle detection event from at least one of vehicle speed and a vehicle length obtained from said first vehicle detection event;

e) constructing a second output pulse corresponding to said second vehicle detection event; and

f) outputting said second output pulse on a second output channel.

2. The method of claim 1 wherein said first output pulse comprises a first pulse-width, and wherein said second output pulse comprises a second pulse-width;

and wherein said second pulse-width is substantially equal to said first pulse-width.

3. The method of claim 1 wherein said first output pulse comprises a first start-time, and wherein said second output pulse comprises a second start-time;

and wherein the difference between said second start-time and said first start-time is chosen to substantially correspond to the quotient of a hypothetical offset distance divided by said vehicle speed, said hypothetical offset distance measured from said vehicle detector.

4. An apparatus for communicating at least one of vehicle speed and vehicle length information gathered from a vehicle detector, said apparatus comprising:

a) a means for measuring at least one of vehicle speed and a vehicle length during a first vehicle detection event;

b) a means for constructing a first output pulse corresponding to said first vehicle detection event;

c) a means for outputting said first output pulse on a first output channel corresponding to said means for measuring;

d) a means for inferring a second vehicle detection event using at least one of said speed and said vehicle length obtained from said first vehicle detection event;

e) a means for constructing a second output pulse corresponding to said second vehicle detection event; and

f) a means for outputting said second output pulse on a second output channel.

5. The apparatus of claim 4 wherein said first output pulse comprises a first pulse-width, and wherein said second output pulse comprises a second pulse-width;

and wherein said second pulse-width is substantially equal to said first pulse-width.

6. The apparatus of claim 4 wherein said first output pulse comprises a first start-time, and wherein said second output pulse comprises a second start-time;

and wherein the difference between said second start-time and said first start-time is chosen to substantially correspond to the quotient of a hypothetical offset distance divided by said vehicle speed, said hypothetical offset distance measured from said vehicle detector.

7. A method for communicating at least one of vehicle speed and vehicle length information gathered from a vehicle detector, said method comprising the steps of:

a) measuring at least one of vehicle speed and a vehicle length using a first vehicle detector during a first vehicle detection event;

b) constructing a first output pulse corresponding to said first vehicle detection event;

c) outputting said first output pulse on a first output channel corresponding to said first vehicle detector, said first output pulse comprising a first pulse-width;

d) inferring from at least one of said speed and said vehicle length information a second vehicle detection event for a second vehicle detector;

e) constructing a second output pulse corresponding to said second vehicle detection event, said second output pulse comprising a second pulse-width, said second pulse-width being substantially equal to said first pulse-width; and

f) outputting said second output pulse on a second output channel corresponding to said second vehicle detector.

8. A method for communicating at least one of vehicle speed and vehicle length information gathered from a vehicle detector, said method comprising the steps of:

a) measuring at least one of vehicle speed and a vehicle length using a first vehicle detector during a first vehicle detection event;

b) constructing a first output pulse corresponding to said first vehicle detection event, said first output pulse comprising a first start-time;

c) outputting said first output pulse on a first output channel corresponding to said first vehicle detector;

d) inferring from at least one of said speed and said vehicle length information a second vehicle detection event for a second vehicle detector;

e) constructing a second output pulse corresponding to said second vehicle detection event, said second output pulse comprising a second start-time, a difference between said second start-time and said first start-time being chosen to substantially correspond to the quotient of a hypothetical offset distance between said first vehicle detector and the second vehicle detector divided by said vehicle speed; and

f) outputting said second output pulse on a second output channel corresponding to said second vehicle detector.

9. An apparatus for communicating at least one of vehicle speed and vehicle length information gathered from a vehicle detector, said apparatus comprising:

a) a means for measuring at least one of vehicle speed and a vehicle length during a first vehicle detection event;

b) a means for constructing a first output pulse corresponding to said first vehicle detection event, said first output pulse comprising a first pulse-width;

c) a means for outputting said first output pulse on a first output channel corresponding to said first vehicle detector;

d) a means for inferring from at least one of said speed and said vehicle length information a second vehicle detection event for a second vehicle detector, said second output pulse comprising a second pulse-width, said second pulse-width being substantially equal to said first pulse-width;

e) a means for constructing a second output pulse corresponding to said second vehicle detection event;

f) a means for outputting said second output pulse on a second output channel corresponding to said second vehicle detector.

10. An apparatus for communicating at least one of vehicle speed and vehicle length information gathered from a vehicle detector, said apparatus comprising:

a) a means for measuring at least one of vehicle speed and a vehicle length during a first vehicle detection event;

b) a means for constructing a first output pulse corresponding to said first vehicle detection event, said first output pulse comprising a first start-time;

c) a means for outputting said first output pulse on a first output channel corresponding to said first vehicle detector;

d) a means for inferring from at least one of said speed and said vehicle length information a second vehicle detection event for a second vehicle detector, said second output pulse comprising a second start time, a difference between said second start-time and said first start-time being chosen to substantially correspond to the quotient of a hypothetical offset distance between said first vehicle detector and the second vehicle detector divided by said vehicle speed;

e) a means for constructing a second output pulse corresponding to said second vehicle detection event; and

f) a means for outputting said second output pulse on a second output channel corresponding to said second vehicle detector.