Road Stacking Determination via Probe Error Statistics
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Solution Overview
Problem
The error associated with altitude data from probe points makes it difficult to determine if one road passes over or under another during map creation, as the large tolerance in altitude data can exceed the vertical spacing between roads, leading to unreliable association of probe points with either road.
Innovation Solution
A method that determines error statistics, such as root mean square error, associated with probe points to identify when one road passes beneath another by analyzing changes in error statistics proximate the second road, using road centerline representations and local orientation lines to accurately determine the stacking order of vertically aligned roads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If altitude data from probe points is used to determine road stacking, then map creation can identify overpasses and underpasses, but the large error tolerance in altitude data (10-50+ meters) exceeds the vertical spacing between roads, making reliable association difficult
Solution Approach 1:
The patent introduces error statistics as an intermediary metric to indirectly determine road stacking. Instead of directly comparing unreliable altitude values, the system calculates error statistics from multiple probe points and uses these statistics to infer stacking relationships, thereby resolving the contradiction between unreliable measurements and the need for reliable determination
Solution Approach 2:
The patent transforms the problem from direct altitude comparison to error statistic analysis. By changing the parameter from raw altitude values to error statistics (such as standard deviation or confidence intervals), the system can reliably determine stacking relationships even when individual altitude measurements have large errors
2Productivity
If probe points with large altitude errors are used for map creation, then more data can be collected, but the vertical spacing between roads cannot be reliably distinguished from measurement noise
Solution Approach 1:
The system uses the collected probe data itself to determine its own reliability. By calculating error statistics from the probe points, the system self-evaluates whether the data can reliably indicate road stacking, allowing continued use of abundant probe data while filtering for reliability through statistical analysis
Data Source
AI summary
A method, apparatus and computer program product are provided to determine the stacking order of two or more roads that are vertically aligned with one another. In the context of a method, error statistics associated with probe points representative of travel along a first road are determined. In an instance in which the first road is vertically aligned with a second road, the method also includes determining whether one of the first or second roads passes beneath the other of the first or second roads based at least in part upon the error statistics associated with the probe points representative of travel along the first road. A corresponding apparatus and computer program product are also provided.