TOPAS PS18

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.

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.

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.