A Time-of-Flight Estimation Method for Acoustic Ranging and Thermometry Based on Digital Lock-In Filtering.

Area of Science:

• Metrology and Measurement Science
• Acoustic Sensing Technologies
• Electrical Engineering

Background:

• Accurate ranging and real-time temperature monitoring are critical for metrology and safety in electrical conduit systems.
• Existing methods may lack robustness and precision under challenging environmental conditions.

Purpose of the Study:

• To propose and validate a novel acoustic time-of-flight (TOF) estimation method using digital lock-in filtering (DLF).
• To enhance accuracy and robustness for ranging and thermometry in electrical conduits.

Main Methods:

• Utilized a linear frequency modulated Chirp signal as the acoustic source.
• Applied digital lock-in filtering (DLF) to extract harmonic frequencies from transmitted and received signals.
• Calculated TOF by analyzing the time-frequency relationship and mathematical expectation of time differences.

Main Results:

• The DLF method established a robust linear time-frequency relationship, confirming TOF measurement accuracy.
• Experimental results demonstrated enhanced noise interference resilience across various conduit lengths and temperatures.
• Achieved lower absolute error and standard deviation compared to conventional methods.

Conclusions:

• The proposed DLF-based acoustic TOF estimation method offers superior accuracy and robustness for conduit ranging and thermometry.
• This technique provides a significant improvement over conventional methods, particularly in noisy environments.