Vehicle Position Detection Using Linear Safety Lines
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Solution Overview
Problem
Existing systems for determining vehicle positions in road networks, particularly in inner-city areas, face inaccuracies due to the use of circular tolerance ranges, leading to overlapping capture circles and potential missed detections at intersections, where the diameter of capture circles must be large to account for GPS inaccuracy, risking false negatives.
Innovation Solution
A system using a snap line defined by spatial coordinates with a reference travel direction and adjustable catch line length, allowing for precise detection of vehicle passage at reference positions by comparing vehicle positions and travel directions, eliminating the need for digital maps and reducing overlapping issues with linear tolerance ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If circular capture circles are used with large diameter to account for GPS inaccuracy, then detection reliability is improved, but measurement precision deteriorates due to overlapping circles at intersections
Solution Approach 1:
The circular capture zone is segmented into a linear capture line extending in the direction of travel. This linear segmentation eliminates the overlapping problem of circular zones at intersections while maintaining the tolerance needed for GPS inaccuracy. The capture line is defined by start and end points along the road direction, providing precise spatial delimitation without the ambiguity of overlapping circles.
Solution Approach 2:
The detection geometry is transformed from two-dimensional circular zones to one-dimensional linear lines extending along the road direction. This dimensional change allows for precise differentiation between adjacent reference points at intersections while still providing sufficient tolerance for positioning errors. The linear extension in the travel direction maintains detection reliability without the overlapping issues of circular approaches.
2Measurement precision
If continuous position updates are performed to ensure accurate detection, then measurement precision is improved, but loss of time increases due to frequent updates
Solution Approach 1:
Instead of continuous position updates, the system performs position determination periodically at specific reference points along the road network. The vehicle position is determined at discrete locations where reference objects are defined, rather than continuously throughout the entire journey. This periodic approach reduces computational overhead and time consumption while maintaining sufficient precision for accurate detection at the reference points.
Solution Approach 2:
Reference positions and capture lines are pre-defined along the road network before the vehicle arrives. The processing unit is pre-configured with the locations and geometries of reference objects, allowing for rapid comparison against stored reference data without requiring complex real-time calculations. This preliminary preparation enables fast position determination at each reference point without continuous processing.
3Measurement precision
If digital maps are carried and updated to correlate vehicle position, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The essential functionality of digital maps is extracted and reduced to minimal reference point data. Instead of carrying and processing complete digital map datasets, the system stores only the necessary reference object locations and capture line geometries along the road network. This extraction eliminates the complexity of full map data management while retaining the ability to precisely correlate vehicle positions with road references at the needed locations.
Solution Approach 2:
Rather than using complex digital map representations, the system creates simplified copies of reference positions as discrete geometric objects (points and lines) stored in the processing unit. These simplified reference representations capture the essential spatial information needed for position correlation without the overhead of full map data structures, achieving precision where needed while minimizing overall system complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances detection reliability and precision in inner-city road networks by clearly distinguishing adjacent reference points, ensuring accurate vehicle passage detection without continuous position updates, and enabling dynamic management of reference positions.
Implementation Method 1
A common solution is a receiver module for satellite signals from a global satellite-based navigation system, such as the American NAVSTAR GPS, the Russian GLONASS, or the European GALILEO system. Using the satellite signals, the device's position, and consequently the vehicle's position, can be determined cyclically
Data Source
AI summary
The invention relates to a system for determining traffic information. Said system comprises a terminal (1) which is carried along in a vehicle (V), said terminal having a position determination device for determining the position (P) of the vehicle (V) in a road network, a storage device for storing reference positions (R) defined by the location coordinates, and a processing device which works together with the position determining device and the storage device. Said processing device is designed to compare a specific position of the vehicle (P) with stored reference positions (R) in order to determine whether the vehicle (V) has passed a reference position (R). According to the invention, a reference position (R) is defined by a safety line (L) extending through the location coordinates thereof, said processing device is designed to determine whether the vehicle (V) has traversed a safety line (L) and to evaluate the traversing of a determined safety line as the vehicle passes the reference position (R) defined by the safety line (L). As a result, a system which can determine a position in a simple and reliable manner, also in an inner-city road network, is provided.