Method and system for electronically determining dynamic traffic information

• US 7,269,507 B2
• Filed: 05/17/2002
• Issued: 09/11/2007
• Est. Priority Date: 05/25/2001
• Status: Expired due to Term

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Cayford, Randall
• Primary Examiner(s): Chin; Gary
• Assistant Examiner(s): WEISKOPF, MARIE
• Application Number:
  US10/478,548
• Publication Number:
  US 20040220728A1
• Time in Patent Office: 1,943 Days
• Field of Search: None
• US Class Current: 701/208
• CPC Class Codes: G01C 21/30 Map- or contour-matching
• CPC Class Codes: G08G 1/096811 where the route is computed offboard
• CPC Class Codes: G08G 1/096844 where the complete route is dynamically recomputed based on new data
• CPC Class Codes: G08G 1/096883 where input information is obtained using a mobile device, e.g. a mobile phone, a PDA

Abstract

A method of and system for determining a path traveled by a vehicle in a road network having a plurality of road segments connected into a plurality of paths that includes obtaining a current location measurement having an accuracy range, determining the road segments located within this accuracy range of the current location measurement to form a set of current possible positions for the vehicle, retrieving a set of stored possible paths for the vehicle, generating a new set of possible paths based on the set of current possible positions and the set of stored possible paths, and storing the new set of possible paths as the set of stored possible paths.

Claims

1. A method of determining a path traveled by a vehicle in a road network having a plurality of road segments connected into a plurality of paths, the method comprising:

obtaining a current location measurement for the vehicle,

wherein said current location measurement has an accuracy range;

determining to road segments located within maid accuracy range of said current location measurement to form a set of current possible positions for the vehicle;

retrieving a set of stored possible paths for the vehicle;

generating a new set of possible paths based on said set of current possible positions and said set of stored possible paths; and

storing said new set of possible paths as said set of stored possible paths.

2. The method of claim 1, further comprising filtering said current location measurement.

3. The method of claim 2,

wherein said set of stored possible paths includes a stored possible path having a previous current location measurement,

wherein said previous current location measurement includes a first timestamp;

wherein said current location measurement includes a second timestamp; and

wherein said filtering includes;

eliminating said current location measurement if the difference between said first timestamp and said second timestamp is less than a minimum travel time,

storing said current location measurement if the difference between said first timestamp and said second timestamp is greater than said minimum travel time.

4. The method of claim 2, wherein said filtering includes eliminating said current location measurement if it is obtained from a non-vehicle source.

5. The method of claim 1, further comprising:

storing a sub-path that is common to all paths in said new set of possible pate,

wherein said sub-path includes a common road segment

removing road segments from each path in said new set of possible paths that precede said common road segment to Loran a set of shortened paths;

storing said set of shortened paths as said new set of possible paths; and

storing said sub-path in broad segment database.

6. The method of claim 1, wherein said generating a new set of possible paths includes:

extending each stored possible path to each current possible position to form a set of extended paths;

storing each extended path having an available travel time that is greater than a minimum travel time; and

removing each extended path having an available travel time that is less than said minimum travel time.

7. The method of claim 6,

wherein said set of stored possible paths includes a stored possible path having a previous current location measurement,

wherein said previous current location measurement includes a first timestamp;

wherein said current location measurement includes a second timestamp; and

wherein said available travel time is the difference between said first timestamp and said second timestamp.

8. The method of claim 1, wherein said obtaining includes obtaining a location measurement from a probe.

9. The method of claim 8, wherein said probe is a GPS receiver.

10. The method of claim 8, wherein said probe is a cellular phone.

11. A system for determining a path traveled by a vehicle along road segments in a road network, the system comprising:

a processor configured to;

receive a current location measurement for the vehicle,

determine the road segments located within an accuracy range of said current location measurement to form a set of current possible positions for said vehicle, and

generate a new set of possible paths based on said set of current possible positions and a set of stored possible paths for the vehicle; and

a database configured to;

store said set of stored possible paths forte vehicle, and

store said new set of possible paths as said set of stored possible paths.

12. The system of claim 11, wherein said processor is further configured to filter said current locution measurement.

13. A computer-readable medium containing computer executable instructions for causing a computer to determine a path traveled by a vehicle in a road network having a plurality of road segments connected into a plurality of paths, comprising instructions for:

obtaining a current location measurement for the vehicle,

wherein said current location measurement has an accuracy range;

determining the road segments located within said accuracy range of said current location measurement to form a set of current possible positions for the vehicle;

retrieving a set of stored possible paths for the vehicle;

generating a new set of possible paths based on said set of current possible positions and said set of stored possible paths; and

storing said new set of possible paths as said set of stored possible paths.

14. The computer-readable medium of claim 13, further comprising filtering said current location measurement.

15. The computer-readable medium of claim 14,

wherein said set of stored possible paths includes a stored possible path having a previous current location measurement,

wherein said previous current location measurement includes a first timestamp;

wherein said current location measurement includes a second timestamp, and

wherein said filtering includes instructions for;

eliminating said current location measurement if the difference between said first timestamp and said second timestamp is less than a minimum travel time,

storing said current location measurement if the difference between said first timestamp and said second timestamp is greater than said minimum travel time.

16. The computer-readable medium of claim 14, wherein said filtering includes eliminating said current location measurement if it is obtained from a non-vehicle source.

17. The computer-readable medium of claim 13, further comprising instructions for:

storing a sub-path that is common to all path, in said new set of possible pat.,

wherein said sub-path includes a common road segment;

removing road segments from each path in said new set of possible paths that precede said common road segment to form a set of shortened paths;

storing said set of shortened paths as said new set of possible paths; and

storing said sub-path in a road segment database.

18. The computer-readable medium of claim 13, wherein said generating a new set of possible paths includes instructions for:

extending each stored possible path to each current possible position to form a set of extended paths;

storing each extended path having an available travel time that is greater than a minimum travel time;

end

removing each extended path having an available travel time that is less than said minimum travel time.

19. The computer-readable medium of claim 18,

wherein said set of stored possible paths includes a stored possible path having a previous current location measurement;

wherein said previous current location measurement includes a first timestamp;

wherein said current location measurement includes a second timestamp; and

wherein said available travel time is the difference between said first timestamp and said second timestamp.

20. The computer-readable of claim 13, wherein said obtaining includes obtaining a location measurement from a probe, a GPS receiver, or a cellular phone.