Train Position Estimation by Railway Track Shape Collation
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Solution Overview
Problem
Existing methods struggle to accurately estimate the position of a train when the railway track shape varies, leading to difficulties in matching railway track shapes and precise position estimation.
Innovation Solution
A position estimation system that includes a railway track information storage unit, a railway track shape measurement unit, a position measurement unit, a section determination unit, and a railway track shape collation unit, which measure and collate railway track shapes at multiple spots to estimate the train's position accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If railway track shape matching is performed using conventional methods, then position estimation can be achieved when track shapes vary significantly, but accurate position estimation becomes difficult when track shapes are similar or do not vary much
Solution Approach 1:
The railway track shape matching process is divided into multiple segments: determining a collation section based on approximate position, measuring track shape at multiple discrete points within that section, and comparing measured shapes at each point. This segmentation allows the system to handle both highly variable and similar track shapes by focusing comparison on localized segments rather than requiring global shape variation.
Solution Approach 2:
The invention transitions from comparing overall track shape patterns to comparing specific geometric parameters (curvature radius, gradient angle) at multiple discrete points along the track. This dimensional change from pattern matching to parameter-based comparison at multiple locations enables accurate position estimation even when overall track shapes are similar, as long as local geometric characteristics differ.
2Measurement precision
If ground coils are installed on railway tracks for position correction, then accurate position estimation can be achieved, but large burden is imposed in cost including installation cost and maintenance cost
Solution Approach 1:
The system uses the train's own measurement capabilities to estimate its position by comparing measured track shape parameters against a pre-stored database. The train essentially measures and compares itself against known track characteristics, eliminating the need for external ground coils or other infrastructure-based positioning systems.
Solution Approach 2:
The invention replaces the mechanical/physical ground coil system with an information-processing-based approach using sensors to measure track geometry and compare against database records. This substitution eliminates the need for physical ground coils while achieving position estimation through computational comparison of geometric parameters.
3Measurement precision
If railway track shape is measured at multiple spots and collated with database, then accurate position estimation can be achieved even when track shapes are similar, but processing load increases
Solution Approach 1:
The system pre-determines a collation section based on approximate position information before performing detailed shape comparison. This preliminary action narrows down the search area to a specific section of the track database, reducing the amount of data that needs to be processed while maintaining accurate position estimation capability.
Solution Approach 2:
The track shape comparison is segmented into discrete measurement points within the collation section. By dividing the continuous track shape into specific measurement locations and comparing parameters at each point, the system reduces processing complexity while maintaining accuracy, as opposed to comparing entire continuous shape profiles.
Data Source
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AI summary
It is an object of the present disclosure to provide a technology with which a position of a car can be accurately estimated. A typical one of position estimation systems of the present disclosure includes: a railway track information storage unit that stores a railway track information database containing a railway track shape at each spot in a railway track; a railway track shape measurement unit that, in a train running on the railway track, measures a railway track shape at least twice; a position measurement unit that measures a position of the train on a railway track; a section determination unit that determines a collation section in the railway track information database based on a position measured by the position measurement unit; and a railway track information collation unit that, in the collation section, collates a DB railway track shape, which is a railway track shape contained in the railway track information data base, with a measured railway track shape, which is a railway track shape measured by the railway track shape measurement unit and estimates a spot on the railway track corresponding to the collated railway track shape as a position of the train on a railway track.