Vehicle Position Estimation Using Overhead Wire 3D Shape Matching
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Solution Overview
Problem
Existing methods for estimating the position of railway vehicles, such as those using overhead wires or transponders, require highly accurate sensors and are prone to errors due to factors like pantograph bounce and wire wear, or require frequent installation of ground equipment, leading to high costs and maintenance needs.
Innovation Solution
A vehicle control system equipped with a sensing unit that measures three-dimensional shapes of contact line equipment like trolley wires and catenaries, using LIDAR for high accuracy, and a matching unit that compares these measurements with pre-stored data to determine vehicle position, eliminating the need for ground equipment and reducing error accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If transponders are installed between rails for position correction, then position estimation accuracy is improved, but infrastructure construction cost and maintenance cost increase
Solution Approach 1:
The patent creates a virtual copy of the overhead wire structure in a database, storing its three-dimensional shape information at various positions. Instead of installing physical transponders, the system uses this digital replica to match against real-time sensor data from the vehicle, enabling position estimation without additional ground infrastructure.
Solution Approach 2:
The patent replaces the mechanical transponder system with an optical sensing system. A sensor on the vehicle measures the three-dimensional shape of overhead wires using light reflection, and this measurement data is compared with the database to determine position, eliminating the need for physical transponders and their associated infrastructure.
2Measurement precision
If transponders are installed at intervals to restrict position errors, then position estimation accuracy is improved, but maintenance requirements increase
Solution Approach 1:
The patent creates a virtual copy of the overhead wire structure in a database, storing its three-dimensional shape information at various positions. Instead of installing physical transponders, the system uses this digital replica to match against real-time sensor data from the vehicle, enabling position estimation without additional ground infrastructure.
Solution Approach 2:
The system uses the existing overhead wire infrastructure that already serves the dual purpose of power supply and position reference. The overhead wires themselves provide the measurement features, eliminating the need for separate transponder systems that would require maintenance.
3Measurement precision
If highly accurate sensors are used to detect overhead wire features, then position estimation accuracy is improved, but device complexity increases
Solution Approach 1:
The patent transitions from using simple one-dimensional features like wire height or position to utilizing three-dimensional shape information. By capturing the full 3D geometry of overhead wires including catenaries and hangers, the system achieves higher measurement precision with a standard sensor rather than requiring highly accurate specialized sensors.
Solution Approach 2:
The patent pre-stores the three-dimensional shape information of overhead wires in a database before the vehicle reaches them. This preliminary preparation allows the vehicle-mounted sensor to perform simple matching operations in real-time, reducing the computational and sensing complexity during actual operation while maintaining high position estimation accuracy.
4Measurement precision
If sensors with high scanning frequency are used to detect marks at high speed, then position estimation accuracy is improved, but device complexity increases
Solution Approach 1:
The patent transitions from using simple one-dimensional features like wire height or position to utilizing three-dimensional shape information. By capturing the full 3D geometry of overhead wires including catenaries and hangers, the system achieves higher measurement precision with a standard sensor rather than requiring highly accurate specialized sensors.
Solution Approach 2:
The patent combines multiple overhead wire features (trolley wire shape, catenary curves, hanger positions) into a unified three-dimensional model. This merging of features creates a more robust position reference that can be accurately detected even at high speeds with standard scanning frequencies, as the combined 3D pattern provides more distinctive matching characteristics.
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 system enables highly reliable and accurate vehicle position estimation without the need for transponders or ground equipment, reducing costs and maintenance while maintaining precise control, even under conditions like pantograph bounce and wire wear.
Implementation Method 1
using LIDAR for high accuracy
Data Source
AI summary
The present invention is provided with: a sensing unit which is provided in a vehicle and measures the three-dimensional shape of an object; a matching unit for performing matching between multiple sets of structure information, in which are associated a data group indicating the three-dimensional shapes of structures provided beforehand near a path the vehicle will travel along and positional information indicating the posit ions of the structures, and a data group indicating the three-dimensional shape of the object measured by the sensing unit, and for specifying the position of the object; and an estimated position determination unit for determining, with the position specified by the matching unit as a reference position, the estimated position of the vehicle on the basis of the reference position.