Vehicle Path Length Determination Using Position Quality Indices
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for determining the length of a vehicle's path using onboard units are limited by measuring inaccuracies and segment resolution of digital road maps, particularly in curved or intersection areas, leading to inaccuracies in path length calculation.
Innovation Solution
A method that generates a sequence of position readings with associated quality indices, filtering out low-quality readings and using a two-stage quality evaluation to determine path length either directly from high-quality readings or through map matching, depending on set quality indices, to achieve higher accuracy and robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If map matching is used to determine path length, then robustness against position reading inaccuracies is improved, but measurement precision deteriorates due to segment resolution limits
Solution Approach 1:
The patent changes the parameter of position reading quality assessment by introducing quality indices and using dynamic thresholding. Instead of always using map matching or always using raw position readings, the system adaptively changes its approach based on the quality parameter of the position readings, selecting the most appropriate method for each specific reading set.
2Measurement precision
If direct calculation from position readings is used, then measurement precision is improved, but reliability deteriorates due to frequent position reading inaccuracies
Solution Approach 1:
The patent implements feedback by continuously assessing the quality of position readings through quality indices and using this feedback to dynamically select the appropriate calculation method. The system monitors the quality parameter and adjusts its behavior accordingly, switching between direct calculation and map matching based on the assessed quality level.
3Productivity
If all position readings are processed, then productivity is improved, but measurement precision deteriorates due to inclusion of low-quality readings
Solution Approach 1:
The patent extracts and removes low-quality position readings from the processing sequence by filtering them out based on quality index thresholds. This selective extraction ensures that only high-quality readings are used for direct calculation, maintaining measurement precision while still processing the maximum useful number of readings.
Data Source
AI summary
Methods are provided for determining the length of a path traveled by a vehicle using an onboard unit that generates a sequence of position readings and a related position quality index for each position reading. A set of consecutive position readings is extracted from the sequence. Position readings are discarded having position quality indices falling below a threshold. A set quality index is determined based on the number of position readings of the set or on the position quality indices. If the set quality index exceeds a threshold, the path length is determined based on mutual distances of consecutive position readings of the set. Otherwise, the path length is determined using a digital road map composed of road segments by associating the position readings of the set with at least one road segment, and determining the path length based on the segment length of the at least one road segment.