Target time smearing with short transmissions and multipath propagation

Area of Science:

• Acoustics
• Oceanography
• Signal Processing

Background:

• Active sonar systems estimate target echo levels using propagation models.
• Multipath arrivals in sonar can lead to signal loss, especially with short transmitted pulses.

Purpose of the Study:

• To analyze the impact of time-smearing loss in active sonar for short pulses.
• To self-consistently estimate target response and signal-to-reverberation-ratio.

Main Methods:

• Modeling multipath arrivals in active sonar.
• Incorporating time-smearing loss into reverberation calculations.
• Assuming isovelocity water, Lambert's law, and angle-dependent reflection loss.

Main Results:

• Target response becomes independent of boundary reflection properties in the short pulse regime.
• Target response is proportional to transmitted pulse length.
• Signal-to-reverberation-ratio becomes independent of pulse length.

Conclusions:

• Time-smearing loss is a critical factor in short-pulse active sonar performance.
• The findings simplify target response and signal-to-reverberation-ratio calculations in specific acoustic conditions.