Network Delay Measurement With GNSS Time Correction
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Solution Overview
Problem
Existing network measurement devices suffer from insufficient time accuracy in delay measurements due to large maximum frequency deviations of internal clocks, necessitating hardware changes that are time-consuming and costly.
Innovation Solution
A network measurement device utilizing a GNSS reception unit, main body clock, frame generation unit, delay measurement unit, and capture unit to correct delay times by calculating offset and slope values from GNSS and main body clock time information, and applying these corrections to measured delay times using captured data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the internal clock of the transmission device is used for delay measurement, then the measurement can be performed, but the time accuracy is insufficient when the maximum frequency deviation is large
Solution Approach 1:
The patent introduces a GNSS reception unit as an intermediary time source that provides highly accurate time information from external satellites. This mediator bypasses the unreliable internal clock frequency deviations, enabling precise delay measurement without being affected by the transmission device's internal clock instability.
Solution Approach 2:
The patent changes the time reference parameter from the internal clock to GNSS time. By obtaining time information from GNSS reception rather than using the device's own oscillator, the system transforms the measurement basis to eliminate frequency deviation errors while maintaining measurement functionality.
2Measurement precision
If hardware changes are made to improve time accuracy, then the measurement precision improves, but the device complexity and cost increase
Solution Approach 1:
Instead of changing the internal clock hardware, the patent uses GNSS reception as an external intermediary time source. This approach improves measurement precision without modifying the device's core hardware architecture, avoiding increased complexity while achieving accurate timing.
Solution Approach 2:
The patent creates a virtual copy of accurate time information from GNSS satellites and uses this copied time data for measurements. Rather than physically changing hardware to achieve better timing, the system replicates accurate time references through software processing of GNSS signals.
3Adaptability or versatility
If the internal clock is used for time synchronization, then the device can operate independently, but the time accuracy deteriorates when frequency deviation is large
Solution Approach 1:
The GNSS reception unit serves as an external time intermediary that enables the device to maintain independent operation while achieving high time accuracy. The device remains self-contained but references external GNSS time signals to correct its internal clock's frequency deviations.
Solution Approach 2:
The system uses GNSS time information as feedback to correct the internal clock's timing errors. By continuously comparing GNSS time with internal clock time and applying offset corrections, the device maintains both independence and accuracy without requiring hardware changes.
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
Improves time accuracy of delay measurements for each frame without requiring hardware changes, ensuring high-accuracy delay time calculations.
Implementation Method 1
a global navigation satellite system (GNSS) reception unit (5) that acquires time information from radio waves from a GNSS satellite
Data Source
AI summary
A control unit 10 that obtains an offset value and a slope of time information from a global navigation satellite system (GNSS) time reception unit 5 and information from a main body clock 7, from captured data acquired by connecting an output port 11 and an input port 12 in a shortest manner, that corrects the delay time obtained from the captured data by the offset value and the slope of the time information from the GNSS reception unit 5 and the time information from the main body clock 7 by measuring a delay time by a delay measurement unit 3 and acquiring the captured data by a capture unit 4, and that corrects the corrected delay time by a maximum value and a minimum value of the delay time measured by the delay measurement unit 3, is included.