The general architecture of a sub-bottom profiler suitable for very shallow waters (<20 m) was defined for use on the coastal launch Haliotis.

The receiver array is separate from the transmitter array to ensure operation in very shallow waters while using frequency-modulated signals of sufficient duration. It uses low frequency, provides excellent vertical resolution, and can acquire data at speeds of up to 7 knots.

Transmitter levels are compatible with a penetration of approximately 20 m.

Example for a water height of 10 m

Characteristics

• Water height: 1–30 m
• Penetration: ~25 m in loose sediment
• Vertical resolution: ~25 cm
• Transmission level: 193 dB ref. 1 µPa at 1 m
• Electronics: Enertest linear 500 VA
• Signal: Chirp 1700-5500 Hz from 10 to 50 ms
• Acquisition speed: up to 7 knots