Sub-bottom profiler, Universal
Traditional sub bottom profilers utilise single frequency fixed length "pinger" type pulses, which reflect from sub sea layers to map the morphology. With the advent of chirp technology and advances in digital processing techniques in the 1990s the science took a step forward with frequency modulated pulses - waveforms that encompass a range of frequencies.
The new GeoPulse Plus system combines the best features of both these technologies and adds higher transmit power combined with digitisation of the return signals at source. Massive over-sampling of the received signals provides high resolution 24 bit data.
GeoPulse Plus is the industry’s only all-digital Sub Bottom Profiler. The appropriate waveform for the intended application is stored in the subsea electronics memory and preselected from a drop-down. New custom waveforms can be added. The transmit transducers are located close to the electronics to minimise transmission loss and the return signal is detected either by these same transducers or by a trailing hydrophone, depending upon the system configuration. The received signal is routed to the Universal Transceiver where the deconvoluted data can be output via Ethernet to any standard acquisition software package.
The Universal Deck Unit is PC based with a monitor and keyboard/ mouse to allow easy operation of system set up. Once up and running the system can be controlled using standard industry software.
The waterproof electronics module is manufactured in aluminium (stainless steel optional) and is rated to 2000 metres (6,562’) water depth. Its internal memory stores the required waveforms, and it utilises a super efficient HV transmitter to deliver high power to the transducers. The return signals received either from the trailing hydrophone or from the transducers are instantly digitised prior to being routed to the Universal Transceiver via a local Ethernet connection or on longer cables via an ADSL link.
Transducers and Hydrophone
The T135 transducers are each rated to an output of 2.5kW and operate efficiently over a wide frequency band of 1.5 - 13 kHz. The trailing single channel hydrophone utilises 8 high-spec elements to capture the return signal and route it via an inline pre-amp to the subsea electronics where it is digitised.
Transducer Deployment Options
Over-The-Side-Mount Ideal for small vessel operations the OTS version utilises an easy to deploy pole and associated universal mounting kit. The transducers are housed in a hydrodynamic pod.
Towed Transducer Vehicle
The Towfish is a proven design and is suitable for towing in deep or shallow waters. The rugged galvanised body and strong fibreglass carapace provide added protection for the transducers and electronics housing while the receive hydrophone is trailed behind. Towfish deployment requires a steel armoured tow cable
The transducers can be mounted in a sea chest either inside the ship’s hull or in a purpose made gondola. The array is usually configured with a total of 4, 9 or 16 transducers. The larger arrays give a narrower beamwidth and are therefore more suitable to deep water applications.