The fault detection of transmitting current encoded by m-sequence using triple-correlation function in...

Area of Science:

• Geophysics
• Signal Processing

Background:

• Helicopter-borne electromagnetic (HEM) systems are crucial for resource exploration.
• Transmitting current waveform quality directly impacts the accuracy of HEM survey results.
• Detecting faults in the transmitting current waveform is essential for reliable data acquisition.

Purpose of the Study:

• To develop a method for detecting faults in m-sequence encoded transmitting current waveforms in HEM systems.
• To improve the reliability and accuracy of HEM data by ensuring transmitting current quality.

Main Methods:

• Application of the triple-correlation function (TCF) to analyze m-sequence encoded transmitting current.
• Extraction of three-dimensional information from normalized TCF plots using peak detection.
• Implementation of a dual-threshold method for fault detection clarification.
• Development of a transmitting current modeling method and conducting 1200 random experiments.

Main Results:

• The triple-correlation function (TCF) effectively reveals bit integrity characteristics of the transmitting current.
• The proposed fault detection method achieved over 83% accuracy for missing bits (1, 2, 4, and 8).
• Laboratory validation using Field Programmable Gate Array (FPGA) confirmed the method's feasibility.

Conclusions:

• The developed TCF-based method provides an effective means for transmitting current waveform fault detection in HEM systems.
• This technique enhances the quality of geophysical detection data.
• The method helps avoid economic losses associated with invalid detection flights.