Impulse source localization in an urban environment: Time reversal versus time matching

Area of Science:

• Acoustics
• Signal Processing
• Urban Environmental Monitoring

Background:

• Accurate localization of impulse sound sources in urban environments is crucial for various applications.
• Existing methods face challenges with signal propagation complexities and real-time processing constraints.
• Distributed sensor networks offer potential for improved sound source localization.

Purpose of the Study:

• To investigate and compare two distinct sound source localization techniques using a finite-difference time-domain (FDTD) model.
• To evaluate the performance of these techniques under controlled processing times in an urban setting.
• To determine the accuracy and practical feasibility of each localization approach.

Main Methods:

• Utilized a finite-difference time-domain (FDTD) numerical model for sound propagation simulation.
• Implemented two localization techniques: time reversal and time matching using a pre-defined simulation database.
• Accelerated simulations by focusing on lower frequencies of impulse signals.
• Validated methods against in situ measurements with varying numbers of sensors (5-15) and source positions.

Main Results:

• The time matching localization technique achieved the targeted 10-meter accuracy in most configurations.
• Time reversal localization performance was hindered by signal masking and distance effects from sensors.
• The study analyzed localization performance based on physical measurements and sensor network configurations.

Conclusions:

• Time matching localization demonstrates superior accuracy and robustness compared to time reversal for urban impulse sound source localization.
• The FDTD model, when optimized for lower frequencies, provides an efficient simulation tool.
• Practical considerations such as real-time processing and hardware requirements are critical for deployment.