Rail Vehicle Positioning via Wireless Signal Phase and Time
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Solution Overview
Problem
Current methods for determining the position of rail-bound vehicles, such as trains, are either costly due to infrastructure requirements or unreliable, especially in underground environments where satellite-based GPS systems fail.
Innovation Solution
A control system and method using radio signal measurements in the time and phase domains between rail-bound vehicles and fixed base stations to determine precise positions, leveraging existing communication infrastructure and enhancing reliability and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If track circuits, axle counters or balises are installed throughout the rail network, then positioning reliability is improved, but infrastructure cost and maintenance cost increase significantly
Solution Approach 1:
The patent repurposes existing wireless communication infrastructure (base stations and vehicle radios) originally designed for communication purposes to also perform positioning functions. By measuring time of arrival and phase of wireless signals, the system derives position information without requiring dedicated positioning hardware, thus achieving multi-functionality from existing infrastructure.
Solution Approach 2:
The system uses the vehicle's own wireless communication radio to both transmit/receive communication signals and measure positioning signals. The vehicle's radio serves dual purposes: maintaining communication with control centers and simultaneously performing self-positioning through signal measurement, eliminating the need for separate positioning receivers.
2Measurement precision
If satellite-based GNSS positioning is used, then positioning accuracy is improved, but reliability deteriorates due to signal weakness and susceptibility to jamming
Solution Approach 1:
The patent introduces base stations as intermediary elements between satellites and vehicles. Instead of relying directly on weak satellite signals that penetrate poorly and are easily jammed, the system uses locally positioned base stations that transmit stronger signals through dedicated wireless communication channels, providing an intermediate positioning reference that is more reliable in underground and urban environments.
Solution Approach 2:
The system replaces satellite-based electromagnetic positioning with a ground-based wireless communication signal measurement system. By substituting the satellite signal mechanism with local base station signals and using time-of-arrival and phase measurements of communication signals, the system achieves positioning without relying on vulnerable satellite infrastructure.
3Ease of manufacture
If satellite-based GNSS positioning is used, then no additional rail network infrastructure is required, but positioning availability deteriorates in tunnels and underground networks
Solution Approach 1:
The patent transitions from space-based satellite positioning to ground-based wireless communication positioning. By changing the dimensional approach from three-dimensional satellite geometry to two-dimensional ground-based base station geometry with wireless signal propagation, the system achieves positioning capability in environments where satellite signals cannot physically reach, such as tunnels and underground networks.
4Measurement precision
If track circuits, axle counters or balises are installed at close intervals, then positioning resolution is improved, but investment cost and maintenance cost increase
Solution Approach 1:
The patent enables existing wireless communication base stations to serve dual purposes: communication and positioning. By measuring time of arrival and phase of wireless signals from these multi-functional base stations, the system achieves fine positioning resolution without installing additional dedicated positioning devices at close intervals, thereby reducing infrastructure quantity while maintaining precision.
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 highly accurate and reliable positioning with reduced maintenance and infrastructure costs, capable of functioning in tunnels and underground systems, offering precision down to a few millimeters and improved safety and reliability compared to existing methods.
Implementation Method 1
measuring a distance to the at least one base station based on measurements of radio signals in a time of flight in the time domain
Implementation Method 2
measuring a distance to the at least one base station based on measurements of radio signals in a phase domain
Data Source
AI summary
A method and system for determining a position of a rail-bound vehicle on a railway is disclosed. The apparatus comprises: a transmitter and receiver for wireless communication with at least one base station arranged at a predetermined position in the vicinity of the railway; a measurement device to determine a distance to the at least one base station based on measurements of the radio signals of the wireless communication in the phase domain; and a controller arranged to determine a present position of the vehicle on the railway based on the distance. A control system/method for controlling rail-bound vehicles in a railway system, and/or an internal or external system related to such rail-bound vehicles, using such position determination is also disclosed.