Train Dead Reckoning Correction Using Wayside Position Inputs
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Solution Overview
Problem
Existing train location determination systems, such as PTC and ACSES, face inaccuracies due to GPS outages and sensor tolerances, leading to large error ranges in dead reckoning that render them unusable for precise location tracking.
Innovation Solution
A system utilizing multiple input devices, including primary (GPS, transponders) and secondary (railroad infrastructure equipment like track circuits, cameras, and LiDAR sensors) to determine train location, with a calculation module to switch between inputs for accurate positioning when primary devices fail or are insufficient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If dead reckoning is used to determine train location when GPS is unavailable, then the system can continue to provide location information, but the error range increases over time making the system unusable
Solution Approach 1:
The system uses wayside equipment as feedback points to periodically correct the dead reckoning position. When the train passes a wayside equipment location, the system compares the dead reckoning position with the actual known position from the database, calculates the position error, and applies correction to reduce the accumulated error range.
Solution Approach 2:
The system dynamically adjusts the dead reckoning parameters by incorporating correction factors derived from wayside equipment observations. The error range parameters are modified based on the discrepancy between dead reckoning predictions and actual positions observed at wayside equipment locations.
2Measurement precision
If multiple input devices including secondary devices are used to extend dead reckoning, then location accuracy is improved, but device complexity increases
Solution Approach 1:
The system uses wayside equipment as intermediary reference points to improve location accuracy without requiring continuous complex sensor arrays on the train. The wayside equipment serves as a mediator that provides periodic position verification and correction, simplifying the onboard system while maintaining accuracy.
3Measurement precision
If primary input devices such as GPS and transponders are used, then location determination is accurate, but the system becomes unusable when these devices are unavailable or provide insufficient information
Solution Approach 1:
The system prepares for primary device failure by having dead reckoning and wayside equipment correction mechanisms ready in advance. This cushioning approach ensures that when GPS or transponders become unavailable, the system can seamlessly transition to alternative methods without loss of functionality.
Solution Approach 2:
The system implements a multi-functional location determination approach that can operate using different combinations of devices (GPS, transponders, dead reckoning with wayside equipment) depending on availability. This universal approach ensures the system remains functional across various operational scenarios and device availability conditions.
Data Source
AI summary
A system to extend dead reckoning includes multiple input devices including primary input devices and secondary input devices, a location system configured to receive position information from the multiple input devices and to determine a location of a train, vehicle or car, the location system including a calculation module that is configured to, through operation of a processor, receive position information from the primary input devices, receive identification information from the secondary input devices and obtain position information of the secondary input devices based on the received identification information, and determine the location of the train with the position information of the primary input devices or determine the location of the train including dead reckoning with the position information of the secondary input devices when the primary input devices are unavailable or provide insufficient position information.