Vehicle Position Specification Using Dynamic Trajectory Deviation
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Solution Overview
Problem
Existing host-vehicle-travel-position specification apparatuses face challenges in accurately determining whether a vehicle is changing lanes on a main road or branching to a fork road when the angular difference between the vehicle direction and road linearity is less than 15 degrees, and they often require external information acquisition equipment, increasing complexity and cost.
Innovation Solution
A host-vehicle-travel-position specification apparatus that includes a position calculation section, map matching section, first and second range specification sections, and a correction section to calculate and correct the vehicle's travel position on a map without external information, using GNSS, gyro sensors, and map data to specify the travel position accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an angular difference threshold of 15 degrees is used to distinguish lane changes from road branching, then the determination is simple and quick, but accuracy deteriorates when the actual angular difference is smaller than 15 degrees
Solution Approach 1:
The invention changes the parameter used for determination from a fixed angular difference threshold to a dynamic criterion based on whether the vehicle position deviates from the map-matching reference trajectory by more than a predetermined distance. This allows the system to accurately distinguish lane changes from road branching regardless of the actual angular difference, resolving the contradiction between quick determination and high accuracy.
2Measurement precision
If external information acquisition equipment such as image capture apparatus is used to improve positioning accuracy, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The invention makes the existing map matching system self-correcting by using the map-matching reference trajectory as a reference. The system automatically detects deviations from the expected trajectory and determines lane changes or road branching based on these deviations, without requiring external information acquisition equipment. This resolves the contradiction by achieving high accuracy through intelligent processing of existing data rather than adding complex hardware.
3Measurement precision
If map matching is continued to one road longer than or equal to a specified distance, then the estimation error range of map matching reference positions is improved, but the response time to detect lane changes or branching increases
Solution Approach 1:
The invention applies partial action by using only the necessary portion of the map-matching reference trajectory (the part where deviation exceeds the predetermined distance) for determination, rather than requiring the vehicle to travel a fixed specified distance. This allows the system to detect lane changes or road branching as soon as sufficient information is available, resolving the contradiction between improving estimation accuracy and reducing detection delay.
Data Source
AI summary
The host-vehicle-travel-position specification apparatus specifies an estimation error range of map matching reference positions based on relation between a map-matching reference trajectory and an estimation error range of estimated absolute positions. The map-matching reference trajectory is corrected to accord with the estimation error range of map matching reference positions. A vehicle travel position is specified based on the corrected map-matching reference trajectory.