Borehole-Surface Micro-Seismic Timing Alignment
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Solution Overview
Problem
The existing borehole-surface micro-seismic monitoring systems face challenges in accurately aligning seismic wave data from surface wireless and underground wired monitoring units due to unstable sampling frequencies, limiting the precision of rock-burst detection and location accuracy.
Innovation Solution
A timing alignment method that involves extracting rock-burst waveform data segments with GPS timestamps, calculating time differences and sampling points, adding sampling times on an equal-interval basis, resampling to a uniform frequency, and using linear interpolation to align the data segments, ensuring synchronized sampling times across both units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If surface wireless monitoring unit and underground wired monitoring unit independently carry out discontinuous timing of sampling data by GPS, then the movement of ground monitoring points is facilitated and underground data quality is ensured, but the sampling frequencies are unstable and the timed data cannot be aligned
Solution Approach 1:
The patent introduces a reference waveform (first waveform) as an intermediary to synchronize the sampling times of surface and underground monitoring units. By aligning both units to this common reference, the unstable GPS timing is corrected without affecting the operational flexibility of ground monitoring point movement.
Solution Approach 2:
The patent changes the timing parameter from unstable GPS-based discontinuous timing to stable reference waveform-based continuous timing. By resampling the waveforms at uniform intervals based on the reference waveform's sampling frequency, the timing alignment precision is improved while maintaining the independent operation capability of each monitoring unit.
2Adaptability or versatility
If surface wireless monitoring unit and underground wired monitoring unit use independent GPS timing, then each unit can operate independently, but the sampling frequencies are unstable and data alignment is limited
Solution Approach 1:
The patent merges the timing reference of surface and underground monitoring units by aligning them to a common reference waveform. This combination approach maintains the independent operation capability of each unit while ensuring their timing synchronization through the shared reference, thus improving reliability without sacrificing adaptability.
Solution Approach 2:
The patent segments the timing synchronization process into two independent steps: first, each unit independently processes its own waveform data; second, both units are aligned to the reference waveform. This segmentation allows independent operation while achieving reliable timing synchronization through the alignment process.
3Productivity
If waveform data segments of different lengths from surface and underground units are directly processed, then the independent sampling process is maintained, but the data cannot be aligned for accurate rock-burst location
Solution Approach 1:
The patent applies dynamic resampling to adapt the sampling frequencies of surface and underground waveform data to match the reference waveform's frequency. This dynamic adjustment allows the system to maintain independent data acquisition while achieving precise alignment for accurate rock-burst location by continuously adapting the sampling rates.
Solution Approach 2:
The patent changes the sampling frequency parameter of the waveform data segments to match the reference waveform's frequency through resampling. This parameter adjustment enables data alignment without compromising the independent acquisition process, as each unit continues to operate independently but with synchronized timing parameters.
Data Source
AI summary
A timing alignment method for data acquired by monitoring units of a borehole-surface micro-seismic monitoring system includes acquiring two rock-burst waveform data segments with GPS timestamps; calculating a time difference and a number of sampling points between each pair of adjacent GPS timestamps; adding, on an equal-interval basis, a sampling time to a sampling point missing a timestamp between each pair of adjacent GPS timestamps; calculating average sampling frequencies of the two rock-burst waveform data segments, adding, on an equal-interval basis, a sampling time to a sampling point missing a timestamp except first and last GPS timestamps in each of the two data segments; obtaining sampling times of all sampling points, resampling the sampling times according to a uniform sampling frequency; calculating a rock-burst waveform data segment at a new sampling time with a linear interpolation formula, and aligning the sampling times of the two rock-burst waveform data segments.