Time Offset Window Calculation for Railway Communication
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Solution Overview
Problem
Existing methods for determining time offsets between communication devices in railway technology lack simplicity and reliability, often resulting in significant deterministic errors.
Innovation Solution
A method involving sequential measurement steps where messages are exchanged between communication devices based on different time bases, with auxiliary windows calculated through extrapolation and intersection to determine a precise time offset window, ensuring high certainty and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing methods for determining time offsets are used, then time offset determination can be performed, but the reliability is insufficient and deterministic errors are significant
Solution Approach 1:
The patent divides the time offset determination into multiple sequential measurement steps (first, second, third, fourth time points) rather than a single measurement. This segmentation allows for multiple auxiliary window calculations and intersections, reducing deterministic errors and improving reliability through repeated measurements and statistical analysis.
Solution Approach 2:
The patent performs more measurements than the minimum single measurement would provide. By conducting multiple measurement steps and calculating multiple auxiliary windows (first auxiliary window from previous time offset window, second auxiliary window from current measurement), the system exceeds basic requirements to achieve higher reliability and reduced deterministic error.
2Measurement precision
If simple time offset determination methods are used, then the procedure is easy to implement, but accuracy and reliability are insufficient for railway technology
Solution Approach 1:
The patent uses feedback from previous measurement results to inform current measurements. The first auxiliary window is calculated by extrapolation from the time offset window determined in previous measurement steps, and subsequent time offset windows are formed by intersecting auxiliary windows from current and previous measurements. This feedback mechanism improves accuracy while maintaining a systematic procedure suitable for railway technology.
3Reliability
If multiple measurement steps with window intersections are performed, then deterministic error is minimized and reliability is improved, but the measurement procedure becomes more complex
Solution Approach 1:
The patent performs preliminary calculations of auxiliary windows before final time offset determination. The first auxiliary window is calculated by extrapolation from previous time offset windows, and the second auxiliary window is calculated from current measurement data before the intersection operation. This preliminary action organizes the complex procedure into manageable stages, improving reliability while maintaining operational clarity.
Data Source
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AI summary
The invention relates inter alia to a method for ascertaining a time offset between a first time base (ZB1) of a first communication device (1) and a second time base (ZB2) of a second communication device (2). According to the invention, there is provision for measurement steps to be performed in succession, wherein each measurement step respectively involves a message (N1) being sent from the first communication device (1) to the second communication device (2) at a first time (T1), which is referenced to the first time base (ZB1), the message (NI) sent by the first communication device (1) being received by the second communication device (2) at a second time (T2), which is referenced to the second time base (ZB2), a message (N2) being sent from the second communication device (2) to the first communication device (1) at a third time (T3), which is referenced to the second time base (ZB2), and the message (N2) sent by the second communication device (2) being received by the first communication device (1) at a fourth time (T4), which is referenced to the first time base (ZB1), for a first auxiliary window (HF1) to be calculated by extrapolation from a time offset window (ZVF) ascertained in a preceding measurement step, for the first, second, third and fourth times of the respective measurement step to be used to calculate a second auxiliary window (HF2), and for set formation between the first and second auxiliary windows (HF1, HF2) to be used to form a time offset window (ZVF) for the current measurement step, said time offset window describing the time offset between the first and second time bases (ZB1) by specifying a range that the time offset is in.