Rail Vehicle Positioning via Digital Map Trajectory Matching
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Solution Overview
Problem
Existing sensors, such as satellite positioning systems and inertial units, lack precision for determining the position and heading of autonomous rail vehicles, especially in environments like tunnels and hilly areas where GPS signals are disrupted.
Innovation Solution
A method that combines data from satellite positioning systems and inertial units with digital maps of railway infrastructure, using reference nodes to determine the trajectory of railway tracks and project measured positions onto this trajectory, accounting for constraints like speed and curvature to calculate the real position of the vehicle, and control its speed based on observed objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If satellite positioning systems and inertial units are used for position determination, then the system can operate in various environments, but the measurement precision is insufficient for autonomous rail vehicle applications
Solution Approach 1:
The patent combines multiple positioning systems (satellite positioning system, inertial measurement unit) with digital map data and railway infrastructure constraints to create an integrated positioning solution. The controller fuses data from GPS/ Galileo satellites, IMU sensors, and pre-stored digital map information about track geometry to achieve precise position determination that overcomes the limitations of individual systems.
Solution Approach 2:
The patent introduces digital maps and railway infrastructure constraints as intermediary elements that mediate between the imprecise sensor data and the required precise position information. The digital maps containing track geometry, reference nodes, and infrastructure constraints serve as a reference framework that enables accurate position calculation by comparing measured positions against known track characteristics.
2Productivity
If GPS signals are used for position determination, then the system can provide position data, but the reliability is disrupted in tunnels, hilly areas, or canyons
Solution Approach 1:
The patent performs preliminary actions by pre-storing digital maps containing detailed railway infrastructure data, including track geometry, reference nodes, and constraints, before the vehicle enters challenging environments. This advance preparation enables the system to switch to map-matching and inertial navigation when satellite signals are unavailable, ensuring continuous reliable positioning through tunnels, hilly areas, or canyons.
Solution Approach 2:
The system cushions against GPS signal disruption by having redundant positioning capabilities pre-configured. When satellite signals are blocked in tunnels or difficult terrain, the system seamlessly transitions to using inertial measurement unit data combined with digital map matching, preventing position determination failures and maintaining operational reliability.
3Device complexity
If standard positioning sensors are used, then the device complexity is low, but the measurement precision is insufficient for determining front end position and heading
Solution Approach 1:
The patent adds the dimension of digital map data and infrastructure constraints to the traditional sensor-based positioning approach. Instead of relying solely on sensor measurements, the system incorporates a fourth dimension of information (pre-stored railway infrastructure data) that enables precise position and heading determination by matching sensor data against known track geometry and reference nodes.
Data Source
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AI summary
The invention relates to a method for determining the position of a railway vehicle (6), the method comprising the following steps: acquiring the data of a measured position (11) from a satellite positioning system (12a) and/or an inertial measurement unit (12b); obtaining a digital map comprising a plurality of reference nodes; determining, from the plurality of reference nodes and the constraints of the railway infrastructure, a trajectory (9) of a segment of a railway track; determining from the determined trajectory (9) and the data of the measured position (11) an actual position (13) of the railway vehicle (6).