Marport has announced a patent-pending multi-function sounder - the CARUSO SF7.
The system is an innovative, high performance, multi-function sounder designed for commercial fishing, fisheries science and oceanographic research applications.
The CARUSO SF7 system consists of a phased array transducer, a software defined transceiver and a bridge computer with display.
To improve signal-to-noise ratio, the transceiver can be placed close to the transducer and linked to the bridge computer via Ethernet. The bridge computer is delivered with Marport’s CommandView software to enable processing, display and recording. The new solution provides seven advanced functions in one:
• Split beam sounder
• Doppler current profiler
• Speed velocity log
• Broadband chirp echosounder
• Sub bottom profiler
• Sea surface temperature
• Bottom classification
Stabilised split beam sounder
The Caruso SF7 split beam sounder utilises an advanced phased array transducer that can transmit on 81 individual 7° beams and receive in 16 quadrants. The sounder’s transmission pulse is applied to the whole transducer. Target detection is determined by comparing the echo signals received by each quadrant. The signals received in each quadrant are processed independently to determine the target strength directly from each echo.
Features of the split beam sounder include:
• Fish size assessment and distribution
• Superior detection zone coverage
• Complete beam stabilisation
• Multiple displays including 3D A-Scope
• Advanced signal modulation
Doppler current profiler
The Caruso SF7 system incorporates a Doppler Current Profiler (DCP) that measures water current velocities over a wide range of depths. The unit can easily interface the vessel’s DGPS input to provide integrated velocity readings with precise position information. The unit’s multiple beam phased array design improves data reliability by providing a redundant data source in the case of a blocked or damaged beam. This also improves data quality by delivering an independent measure known as error velocity and improves data accuracy. The transducer elements can be aimed in such a way that the multifrequency sound pulses travel through the water in different, but known directions. As the echo of the sound is returned by echo scatters in the water, it is shifted in frequency due to the doppler effect. The unit uses advanced digital signal processing (DSP) to deliver very low-noise data, resulting in unparalleled fine track resolution and very accurate velocity profiles.
Broadband chirp echosounder
The Caruso SF7 system incorporates a broadband echosounder that utilises advanced frequency modulation (CHIRP FM) and digital signal processing to provide significantly improved range resolution and superior target discrimination when compared to fixed-frequency echosounders. The system’s software defined architecture enables digital signal processing to be performed in software which can be programmed 'on-the-fly' to utilise any frequency, bandwidth, or pulse length.
Sub bottom profiler
The Caruso SF7 system includes a sub-bottom profiler that operates in water depths from to 3,000m. The sub bottom profiler function is 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 small side lobes. All these features results in very high spatial resolution in the sediment profiles. The narrow beam results in lower received reverberation and higher penetration.
Advanced phased array transducer
The transducer is built in a phased array configuration and can be aimed to transmit multi-frequency, broadband, sound pulses through the water. The transducer design provides a wide range of possibilities for electronic control of the beams around and below the vessel.
The Caruso SF7 sounder is currently undergoing sea trials and will be commercially available in November 2008.
