Method and system for automatic centerline adjustment of shape point data for a geographic database

• US 6,366,851 B1
• Filed: 10/25/1999
• Issued: 04/02/2002
• Est. Priority Date: 10/25/1999
• Status: Expired due to Term

• Current Assignee: HERE Global B.V. (Nokia Corporation)
• Original Assignee: Navigation Technologies Corp. (Nokia Corporation)
• Inventors: Chojnacki, Robert, Feigen, Jerry, Boylan, A. Merri
• Primary Examiner(s): Camby, Richard M.
• Application Number:
  US09/426,341
• Time in Patent Office: 890 Days
• Field of Search: 701/201, 701/208, 701/209, 701/210, 701/211, 701/213, 340/995
• US Class Current: 701/208
• CPC Class Codes: G01C 21/3811 Point data, e.g. Point of Interest [POI]
• CPC Class Codes: G01C 21/3819 Road shape data, e.g. outline of a route
• CPC Class Codes: G01C 21/3844 Data obtained from position sensors only, e.g. from inertial navigation

Abstract

A process and system for collecting data about roads located in a geographic area and using the collected data to develop representations of the roads for a geographic database. Data representing positions along roads are acquired using equipment installed in a vehicle which is driven on the roads. The data acquired while driving may be smoothed and fused. The data acquired while driving are processed by a program that automatically determines new coordinates to adjust the represented positions to align with the centerlines of the represented roads. Data including the new coordinates are stored in the geographic database.

Claims

1. A method of storing data in a geographic database to represent roads, the method comprising the steps of:

from a collection of source data that represent points along said roads, determining new positions for those points represented by said source data, wherein said new positions have coordinates that are adjusted to align with centerlines of the roads represented thereby; and

storing data that represent said new positions in a geographic database.

2. The method of claim 1 wherein said collection of source data is acquired while driving a vehicle along said roads.

3. The method of claim 1 wherein said collection of source data comprises raw sensor data.

4. The method of claim 1 wherein said collection of source data comprises raw sensor data formed as a result of a fusing step in which each raw sensor reading is modified to take into account sensor readings from a plurality of different types of sensors.

5. The method of claim 1 wherein said source data are acquired using an inertial sensor system and a GPS system.

6. The method of claim 1 further comprising the step of:

determining which of said points are necessary to represent the roads with a desired level of accuracy,

and wherein the data stored in the geographic database excludes those points that were not determined to be necessary to represent the roads with the desired level of accuracy.

7. The method of claim 6 wherein said step of determining which of said points are necessary to represent the roads with a desired level of accuracy is performed prior to the step of determining new positions.

8. The method of claim 7 wherein said step of determining which of said points are necessary to represent the roads with a desired level of accuracy is based upon an evaluation of said points such that a straight line connecting any two adjacent necessary points is not farther from any unnecessary points located between said two adjacent necessary points than a distance associated with said level of accuracy.

9. The method of claim 7 wherein said step of determining which of said points are necessary to represent the roads with a desired level of accuracy is based upon an evaluation of said points such that each point not determined to be necessary is located less than a distance associated with said level of accuracy away from a straight line that connects the closest necessary points on either side of said point determined not be necessary.

10. The method of claim 6 wherein said level of accuracy is specified to be less than approximately 1 meter.

11. The method of claim 6 wherein said level of accuracy is specified to be a value between approximately 3 and 5 meters.

12. The method of claim 6 wherein said level of accuracy is specified to be a value between approximately 1 and 3 meters.

13. The method of claim 1 wherein at least some of said centerlines correspond to a line extending along a center of all the lanes that form a represented road.

14. The method of claim 1 wherein at least some of said centerlines correspond to a line extending along a center of all the lanes of a represented road that have an identical legal direction of travel.

15. The method of claim 1 wherein, for those roads whose shape is represented by a single grouping of points, said centerlines correspond to lines extending along centers of all the lanes that form the respective represented roads and, for those roads represented by separate groupings of points for each direction of travel, said centerlines correspond to lines extending along centers of each of said grouping of lanes that form the respective represented roads.

16. The method of claim 1 wherein each new position, for those roads each of whose shape is represented by a single grouping of points, corresponds to a displacement equal to a lane width times a total number of lanes divided by two plus one-half the lane width from the respective point along the road from which the new position was derived.

17. The method of claim 1 wherein each new position, for those roads each of whose shape is represented by a single grouping of points, corresponds to a displacement equal to a sum of the widths of all the lanes divided by two plus one-half the lane width of the rightmost lane from the respective point along the road from which the new position was derived.

21. The geographic database stored on a computer readable medium formed using the process of claim 1, 18, or 20.

18. A method of forming a geographic database comprising:

driving in a rightmost lane of roads with a vehicle equipped with a positioning system that acquires data representative of positions of said vehicle over time as said vehicle travels along said roads;

using an automatic centerlining program to determine, for at least some of said positions represented by said acquired data, new positions along centerlines of said roads, wherein said new positions are determined by a displacement relative to said positions represented by said acquired data; and

storing data that represent the new positions in a geographic database.

19. The method of claim 18 further comprising the step of:

after the step of driving in a rightmost lane, determining which of said positions represented by said acquired data are necessary to represent the roads with a desired level of accuracy.

20. A method of forming a geographic database comprising:

providing as an input to an automatic centerlining program a collection of source data that represent points along said roads acquired by a data collection system located in a vehicle that traveled along said roads;

with said automatic centerlining program, determining new positions, wherein said new positions are displaced relative to said positions represented by said acquired data by an distance corresponding to a distance between a lane in which said vehicle traveled and a centerline of the corresponding road; and

storing data that represent the new positions in a geographic database.