Sub-bottom profiler of the Haliotis

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


  • 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