Evaluation of target angular position algorithms for multi-beam fishery sonars

Area of Science:

• Acoustics
• Fisheries Science
• Signal Processing

Background:

• Accurate target localization is crucial for effective fisheries acoustic surveys.
• Existing multi-beam sonar systems require precise angular position measurement methods.
• Evaluating different algorithms for target tracking enhances sonar system performance.

Purpose of the Study:

• To describe and compare two algorithms: Split-Beam (SB) and Interpolated Neighbouring Beam (INB).
• To assess the precision and accuracy of these algorithms for measuring target angular position using fishery sonar.
• To determine the suitability of the algorithms for real-time applications in fisheries acoustics.

Main Methods:

• Development of theoretical models for SB and INB algorithms applied to a cylindrical transducer array.
• Implementation and testing of algorithms using simulated and real-world sonar data.
• Field calibration of sonar systems to evaluate algorithm performance.

Main Results:

• Both SB and INB algorithms achieved high precision (±0.2-0.25°) for targets near the acoustic axis.
• SB algorithm demonstrated accurate target localization throughout the main acoustic beam.
• INB algorithm accuracy was limited to a narrow sector (±1.5°-±2.5°) near the acoustic axis, varying with frequency.

Conclusions:

• The Split-Beam algorithm provides reliable, real-time target position tracking suitable for fisheries acoustic surveys.
• The INB algorithm's accuracy is constrained, limiting its application compared to SB.
• Algorithm choice significantly impacts the precision and spatial coverage of target localization in fisheries acoustics.