Railway Height Profile Determination Using GNSS Carrier Phase and RTK
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Solution Overview
Problem
Existing driver assistance systems for rail vehicles face challenges in obtaining accurate and up-to-date height profile data, which is crucial for energy-efficient operation, due to unreliable and outdated information of unknown origin, requiring manual entry and processing, leading to inefficiencies and inaccuracies in driving recommendations.
Innovation Solution
A method utilizing a GNSS receiver on the rail vehicle to record position and height data, enhanced by carrier phase measurements and RTK differential correction, allowing for precise and quick determination of the height profile, independent of route operators or countries, with additional considerations for geoid undulation, multiple directions of travel, and adaptive measurement intervals to optimize data accuracy and system performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If height profile data is requested from route operators, then data can be obtained, but the data is mostly outdated, of unknown origin and quality, requiring manual entry and processing
Solution Approach 1:
The rail vehicle autonomously records its own position and height data using onboard GNSS receivers during normal operation, eliminating the need for manual data entry by operators. The system self-collects, processes, and stores height profile data automatically
Solution Approach 2:
Manual data entry and processing is replaced by automated electronic data acquisition using GNSS technology. The mechanical/manual process of collecting and entering data is substituted with satellite-based positioning and automatic digital recording systems
2Ease of manufacture
If conventional GNSS measurements are used, then data acquisition is simple, but the accuracy of height data is insufficient for reliable gradient calculations
Solution Approach 1:
The system performs preliminary actions by continuously recording and storing position and height data during normal vehicle operation. Data is collected in advance and processed later to determine accurate height profiles, preparing the information needed for gradient calculations before it is actually required
Solution Approach 2:
The system creates a digital copy of the physical route profile by recording GNSS position and height data along the entire route. This digital representation is then processed to generate accurate gradient information, replacing the need for physical surveying methods
3Measurement precision
If the rail vehicle travels the route to record height data, then accurate and up-to-date information is obtained, but time is required for data collection
Solution Approach 1:
The GNSS receiver continuously records position and height data during the entire journey along the route, without interruption or special measurement phases. This continuous data collection ensures complete coverage and maintains accuracy while utilizing normal operational time
Solution Approach 2:
Data collection occurs during normal vehicle operation rather than requiring separate survey trips. The useful action of transporting the vehicle simultaneously performs the measurement function, eliminating dedicated data collection time
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 method provides a highly accurate and reliable recording of the height profile, significantly improving the accuracy and efficiency of driver assistance systems by enabling fast and precise data acquisition, reducing manual effort, and enhancing the calculation of driving recommendations.
Implementation Method 1
position and height data are recorded by a receiver of a global navigation satellite system (GNSS) installed in the rail vehicle
Implementation Method 2
the carrier phase being used to increase the accuracy of the height data contained via the GNSS of the signals of the navigation satellite or satellites
Implementation Method 3
the height data is subjected to a differential correction with the aid of an RTK network
Data Source
Figure 1
AI summary
A method for determining the altitude profile of a section of track for a rail vehicle has the following method steps: acquiring position data and altitude data by means of a receiver, installed in the rail vehicle, of a global navigation satellite system (GNSS) when the section of track is travelled along at least once; increasing the accuracy of the altitude data obtained by means of the GNSS by determination of the carrier phase of the signals of the navigation satellite or satellites; increasing the accuracy of the altitude data which are obtained by means of the GNSS by differential correction of the altitude data with the aid of an RTK network; and calculating the variation in the altitude profile of the section of track by processing of the position data and altitude data acquired in the preceding steps.