Path curve confidence factors

摘要

In one embodiment, navigational features of a navigation device are activated or deactivated according to the accuracy of the geographic data. The navigation features may be predictive features related to upcoming portions of a path curve. The path curve is compared to measured data. For example, a first curve is accessed from a map database and a second curve is based on measured position data collected while traversing the path. The first curve and the second curve correspond to the same geographic area. A difference of an attribute between a section of the first curve and a section of the second curve is used to assign a confidence factor to the section of the first polycurve based on the difference. The attribute may be heading, position, curvature, or another aspect of the path curves.

主权项

1. A method comprising:
obtaining a first spline representing a path from a map database; generating a second spline based on measured position data collected while traversing the path; performing, with a processor, an alignment between a section of the first spline spanning a geographic distance and a section of the second spline corresponding the geographic distance, wherein the section of the first spline corresponds geographically to the section of the second spline; calculating, with a processor, a relative error (RE) between a first attribute (A1) for the section of the first spline spanning a geographic distance and a second attribute (A2) for the section of the second spline corresponding the geographic distance according to:
RE=(A1−A2)/A2, wherein the section of the first spline corresponds geographically to the section of the second spline; assigning a confidence factor for a navigation feature to the section of the first spline based on the relative error; identifying a section of the second spline corresponding the geographic distance; comparing the section of the second spline based on measured position data to a minimum curve threshold, wherein when the section of the second spline exceeds the minimum curve threshold, the alignment is performed, and when the section of the second spline is less than the minimum curve threshold, the section of the second spline is excluded from alignment; and reporting the confidence factor to a map developer.