Train Positioning via Passive Structure Recognition and Satellite Fusion
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Solution Overview
Problem
Existing train positioning methods require the installation of active trackside structures like balises, which are costly and cumbersome to maintain, especially in extensive railway networks.
Innovation Solution
A method using satellite navigation combined with imaging techniques for train positioning, eliminating the need for active trackside structures by utilizing passive infrastructure such as rail elements and buildings, and integrating data fusion from multiple independent localization stages for enhanced accuracy and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If active trackside structures like balises are installed along the track for train positioning, then positioning reliability is improved, but device complexity and installation cost increase
Solution Approach 1:
The patent extracts the active balise components from the trackside environment and replaces them with passive infrastructure elements. The positioning system uses existing passive structures (signals, signs, buildings, bridges) that are already present in the railway environment, eliminating the need to install additional active balises along the track while maintaining positioning capability through image recognition and feature matching algorithms
Solution Approach 2:
The patent replaces the mechanical/electrical balise system with an optical sensing system. Instead of using active radio transponders that require electrical circuits and signal generation, the system uses optical cameras and image processing to identify and track passive trackside structures, substituting the mechanical positioning infrastructure with an information-processing-based approach
2Measurement precision
If active balises are installed all along the track for continuous position determination, then positioning precision is improved, but loss of substance and installation cost increase
Solution Approach 1:
The patent makes the existing passive trackside infrastructure serve multiple functions: they continue to fulfill their original signaling and safety functions while simultaneously serving as positioning references. This multi-functionality eliminates the need for dedicated positioning hardware, reducing material consumption and installation resources while maintaining positioning precision through the use of these universal infrastructure elements
3Device complexity
If passive trackside structures are used for positioning without active equipment, then device complexity is reduced, but measurement precision may deteriorate
Solution Approach 1:
The system employs continuous feedback through image capture and processing to maintain positioning accuracy. The on-board system captures images of passive trackside structures, processes them to identify features and calculate position, and continuously updates the train's position information. This feedback loop ensures that positioning precision is maintained despite using passive structures, as the system adapts to varying conditions in real-time
4Reliability
If satellite navigation and imaging methods are combined for positioning, then reliability is improved through redundancy, but device complexity increases
Solution Approach 1:
The patent segments the positioning system into distinct functional modules: a first localization stage using passive trackside structure recognition and a second localization stage using satellite navigation. Each stage operates independently with its own sensors and processing algorithms, allowing the system to achieve high reliability through redundancy while managing complexity through modular architecture. The segments can be activated based on availability and reliability of individual systems
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 provides a safer and more cost-effective method for determining train position, achieving a superior safety level comparable to state-of-the-art systems without the need for extensive active infrastructure, and ensuring reliable operation even in case of systematic failures.
Implementation Method 1
By identifying passive trackside structures in the environment, which are registered in a map data base stored in the on-board unit, a first position information about the train is derived
Implementation Method 2
By means of a second localization stage, satellite navigation is applied in order to derive a second position information about the train
Implementation Method 3
By a data fusion of the first and second position information, a consolidated position information about the train is obtained
Data Source
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Figure 2b
AI summary
A method for safely determining a position information of a train (58) on a track, wherein an on-board system (1) of the train (58) identifies trackside structures, is characterized in that the trackside structures comprise passive trackside structures (56, 56a-56e) which are passive in their identification by the on-board system (1), wherein the on-board system (1) determines appearance characteristics, current distances (93) relative to the train (58) and current angular positions (94, 95) relative to the train (58) of the passive trackside structures (56, 56a-56e) by means of a first sensor arrangement (60) of a first localization stage (50) of the on-board system (1), wherein the on-board system (1) stores a map data base (10) in which georeferenced locations (100) and appearance characteristics of the passive trackside structures (56, 56a-56e) are registered, wherein the first localization stage (50) allocates (14; 29, 28) passive trackside structures (56, 56a-56e) measured by the first sensor arrangement (60) to passive trackside structures (56, 56a-56e) registered in the map data base (10) using the determined appearance characteristics and the registered appearance characteristics, that a first position information (52) about the train (58) is derived (14; 30) from a comparison of determined current distances (93) and current angular positions (94, 95) and the registered locations (100) of allocated passive trackside structures (56, 56a-56e) by the first localization stage (50), that a second position information (54) about the train (58) is derived from satellite signals determined by a second sensor arrangement (61) of a second localization stage (51) of the on-board system (1), and that the first position information (52) and the second position information (54) undergo a data fusion (19), resulting in a consolidated position information (55) about the train (58). The inventive method allows determining a position information of a train, which is less cumbersome and less expensive in installation and operation, however provides and equivalent level of safety compared to state of the art train positioning methods.