Parametric sub-bottom profiler

TOPAS PS18 is designed for sub-bottom profiling with very high spatial resolution in water depths from less than 20 metres to full ocean depth. The +80% relative bandwidth, low frequency signal is generated in the water column by non-linear interaction between two high frequency signals (centred symmetrically around 18 kHz). Similarly, a sum frequency signal is also generated. However, only the low frequency signal is used for sub-bottom profiling.

System Components

The Kongsberg TOPAS PS 18 parametric sub-bottom profiler is a comprehensive system that includes several integral units. It features a Transducer with 8 x 16 channels, and a Transceiver Unit that comes with a linear, switched mode power amplifier, a built-in T/R-switch, a low noise receiver with a 24-bit ADC, and a high dynamic range surpassing 110 dB. The system's Operator Console is equipped with MMI, capable of real-time processing, and operates on a PC-based platform using Windows. Additionally, there is an optional component comprising a Multi-channel receiver (MCR) and beamformer, offering enhanced functionality.

Beam Technology and Transducer Deployment

This profiler utilizes parametric sources capable of generating a low-frequency signal beam without a distinct sidelobe structure. This unique design ensures a smooth tapering off of the beam, effectively reducing the risk of spurious signals from sidelobes in the received signal. The transducer of this system is hull-mounted, which offers significant advantages. This configuration eliminates the need for deploying or recovering tow-fishes during surveys, leading to more efficient survey operations and improved positioning accuracy. Additionally, the system's design enhances the vessel's maneuverability. When used on a “low noise” vessel, it can achieve excellent profiling results, even at survey speeds exceeding 14 knots.

Performance and Operational Versatility

The Kongsberg TOPAS PS 18 is designed for operational flexibility, able to work with various signal waveforms to ensure optimum performance. It typically employs Ricker pulses for high-resolution tasks, Chirp pulses for deep water and high penetration applications, and CW pulses for narrow band, frequency-sensitive operations. The system's transmitted beam is electronically stabilized in roll, pitch, and heave, requiring input from a vertical reference unit, which ensures accurate positioning of the insonified area on the sea floor. The transmitter's beam steering mode, which sequentially covers a larger sector, is crucial in object detection and location applications. The profiler's penetration performance varies depending on several factors such as sediment characteristics, water depth, transmitted signature, and noise level. Remarkably, it has achieved penetration of over 200 meters in water depths exceeding 3,800 meters, with a sediment layer resolution typically around 15 cm or better.

Key features

  • Narrow acoustic beam
  • High bandwidth
  • Chirp and short pulse modes
  • No sidelobes
  • Electronic beam steering
  • Single ping, multi ping and burst ping modes
  • Real-time processing
  • Heave, roll and pitch stabilised beam
  • Hull mounted transducer
  • High spatial resolution


Data sheet

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