Parametric Sub-bottom Profiler Systems
The TOPAS parametric sub-bottom profiler family are based on low frequency sound generation due to non-linear interaction in the water column from two high intensity sound beams at higher frequencies. The resulting signal has a high relative bandwidth (~80%), narrow beam profile (close to the transmitted high frequency signals) and no sidelobes. All these features results in very high spatial resolution in the sediment profiles. The narrow beam also results in lower received reverberation levels and thus higher penetration.
Reduced transducer size
By generating low frequency signals in this way, the transducer size is reduced by a factor from 15 to 300, depending on frequencies) relative to conventional sub-bottom profiler generating the same beam width. This advantage makes it possible to install low frequency, narrow beam systems on small vessels.
Three parametric sub-bottom profiler systems are available
The TOPAS family currently include the PS 18, PS 40 and PS 120 stand-alone parametric sub-bottom profilers:
- TOPAS PS 18 sub-bottom profiler – designed for use in water depths from <10 meters to full ocean depth operation
- TOPAS PS 40 sub-bottom profiler – designed for high resolution, medium depth – between <5 and >1000 meter operation.
- TOPAS PS 120 sub-bottom profiler – designed for very high resolution, shallow depth – between <3 and >400 meter operation. Portable system.
Simple system integration
All TOPAS systems can be integrated with standard navigation systems, vertical reference systems (EM3000-format output, etc.), synchronizing unit (Ksync) etc. The systems can also distribute the received data blocks on the Ethernet so operators using a slave PC connected to the network, can look at, process and store data locally in real-time. However, he is not allowed to modify critical operational system settings.
The PS 18 system can, as an option, use the low frequency channels of the EM 122 receiver array, as input. In this case an additional multi channel receiver unit including beamformer is installed. The narrow receiver beam for the EM 122 system improves signal-to-noise ratio and increases performance of the TOPAS system.
All TOPAS systems can receive slope information from the EM MBES to steer the beam perpendicular to the seabed for better performance. External depth information can also be received for improved operational reliability.