Method of operating a navigation system to provide road curvature

• US 8,204,680 B1
• Filed: 07/05/2007
• Issued: 06/19/2012
• Est. Priority Date: 07/05/2007
• Status: Active Grant

• Current Assignee: HERE Global B.V. (HERE Holding Corporation)
• Original Assignee: Navteq B.V. (HERE Holding Corporation)
• Inventors: Dorum, Ole Henry
• Primary Examiner(s): Elchanti, Hussein
• Assistant Examiner(s): Khatib, Rami
• Application Number:
  US11/825,208
• Time in Patent Office: 1,811 Days
• Field of Search: 701/25, 701/26, 701200-226, 703/2, 345441-443, 340/995.1, 340/995.22, 340/995.24, 340/995.25
• US Class Current: 701/411
• CPC Class Codes: G01C 21/3697 Output of additional, non-guidance related information, e.g. low fuel level G01C21/3679 takes precedence

Abstract

A computer implemented method of operating a navigation system to provide road curvature is provided. The method comprises obtaining a plurality of spline control points representing a two-dimensional geometry of a portion a road segment and obtaining data indicating a road grade of the portion of the road segment. The spline control points and data indicating road grade are obtained from a geographic database associated with the navigation system. The method further comprises projecting the spline control points onto a slope provided by the road grade to obtain a representation of a restored true road curvature of the portion of the road segment.

Claims

1. A computer implemented method of operating a navigation system to provide road curvature comprising:

obtaining, using a processor, a plurality of spline control points representing a two-dimensional geometry of a portion of a road segment from a geographic database associated with said navigation system, wherein each of the spline control points lies on or close to a point along the represented road segment, wherein each of the spline control points comprises a latitude and longitude coordinate pair;

obtaining, using the processor, data indicating a road grade of said portion of said road segment from said geographic database; and

projecting, using the processor, said spline control points onto a slope plane having a slope provided by said road grade to obtain a plurality of projected spline control points, wherein the projected spline control points provide a representation of a restored true road curvature of said portion of said road segment that restores altitude components to the road curvature, wherein each of the projected spline control points comprise a latitude, longitude and altitude coordinate triple.

2. The method of claim 1 further comprising providing said plurality of projected spline control points to an ADAS safety system.

3. The method of claim 2 wherein said ADAS safety system is a curve warning system.

4. The method of claim 1 further comprising evaluating said road grade to determine whether a magnitude of the road grade of said road segment is larger than a predetermined amount, if so performing said projecting step.

5. The method of claim 1 further comprising identifying a road on which a vehicle associated with said navigation system is traveling.

6. A computer implemented method of operating a navigation system to provide road curvature comprising:

obtaining, using a processor, data indicating a degree of curvature of a portion of a road segment from a geographic database associated with said navigation system;

if the degree of curvature is greater than a predetermined amount, obtaining, using the processor, data indicating a road grade of said portion of said road segment and projecting, using a processor, a plurality of spline control points representing a two-dimensional geometry of a portion of a road segment onto a slope plane having a slope provided by said road grade to obtain a plurality of projected spline control points, wherein the projected spline control points provide three-dimensional geometry of the portion of the road segment and providing the projected spline control points to an ADAS safety system; and

if the degree of curvature is less than a predetermined amount, do not project the plurality of spline control points representing the two-dimensional geometry of the portion of the road segment onto the slope plane.

7. A computer implemented method of operating a navigation system to provide road curvature comprising:

obtaining, using a processor, data indicating a road grade of a portion of a road segment from a geographic database associated with said navigation system;

if the road grade is greater than a predetermined amount, projecting, using the processor, a plurality of spline control points representing a two-dimensional geometry of a portion of a road segment onto a slope plane having a slope provided by said road grade to obtain a plurality of projected spline control points, wherein the projected spline control points provide three-dimensional geometry of the portion of the road segment and providing the projected spline control points to an ADAS safety system; and

if the road grade is less than a predetermined amount, do not project the plurality of spline control points representing the two-dimensional geometry of the portion of the road segment onto the slope plane.