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Efficient processing power harmonic noise with fluctuation frequency in urban transient electromagnetic surveys
Sihe Huang1, Shengjie Wang1, Yishu Sun1
1Key Laboratory for Geophysical Instrument of Ministry of Education, Jilin University, Changchun 130061, China and College of Instrumentation and Electrical Engineering, Jilin University, Changchun 130061, China.
The Review of Scientific Instruments
|July 10, 2021
Summary
This study introduces a new method to remove fluctuating power harmonic noise in transient electromagnetic (TEM) surveys. The technique effectively suppresses noise without distorting the TEM signal, improving urban survey data quality.
Area of Science:
- Geophysics
- Electromagnetism
- Signal Processing
Background:
- Power harmonic noise is a significant interference in urban transient electromagnetic (TEM) surveys.
- Traditional methods struggle with fluctuating fundamental frequencies of power harmonic noise, reducing their effectiveness.
Purpose of the Study:
- To develop an effective method for suppressing power harmonic noise with fluctuating frequencies in TEM surveys.
- To improve the quality of TEM data collected in noisy urban environments.
Main Methods:
- Proposed a same-phase and adjacent power harmonic noise subtraction method using bipolar waves.
- Utilized the wavelet-Nyman, Gaiser, and Saucier estimator to accurately determine fluctuating harmonic frequencies.
- Adjusted TEM working frequency and duty cycle to align noise phases for subtraction.
Main Results:
- The proposed method efficiently removes power harmonic noise even with fundamental frequency fluctuations.
- TEM signals remain undistorted after noise suppression.
- The new method outperforms traditional techniques in suppressing power harmonic noise.
Conclusions:
- The developed method offers a robust solution for mitigating power harmonic noise in TEM surveys.
- This technique enhances the reliability and accuracy of geophysical data acquired in urban settings.
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