Sonar technology company Marport Deep Sea Technologies introduced its latest software defined sonar products at the Nor-Fishing 2010 exhibition in Trondheim, Norway.
The company’s new Broadband Acoustic Transceiver utilises multiple software defined digital signal processors for real-time display and processing of passive and active acoustic signals from 1 kHz to 1.8 MHz.
It has support for up to 60 sensor channels including 10 simultaneous operational net sounders. The rack-mount unit is interfaced with PC-based display and control workstations over a high speed network.
The scalable, open architecture supports expansion to accommodate additional signal processing hardware, new operator tools and emerging customer requirements. The unit employs adaptive narrowband interference rejection techniques to provide enhanced system performance and acoustic signal reception when compared to conventional systems.
The frequency-agile transceiver decodes multiple underwater communications protocols from a wide variety of third party manufacturers of sensors, net sounders, sonars and related acoustic hardware.
One Broadband Acoustic Transceiver can replace multiple older bridge cabinets which can significantly reduce the need for expensive bridge equipment and associated maintenance costs, said Marport.
Key attributes of the Broadband Acoustic Transceiver include: dynamically-tunable broadband operation, noise rejection, high linearity, flat frequency response and a rugged 19” rack-mount package with complete opto-isolation.
The unit includes an embedded PC running a Linux server for system configuration/diagnostics and is completely controlled via a web browser. It supports Ethernet and NMEA 0183 and can be interfaced to any commercially available PC.
The transceiver has automatic hydrophone selection and supports passive and active hydrophones from a wide variety of manufacturers.
Doppler Trawl Velocity Sensor
Marport’s new Doppler Trawl Velocity Sensor is the world’s first multi-function Doppler speed sensor designed specifically for deepsea commercial fishing applications, the company said.
The sensor utilises a Marport-developed micro-size Doppler Velocity Log to continuously measure the dual axis velocity of trawl (ie fore-aft, port-starboard) and transmit this information to the vessel via a wireless acoustic data link.
Operators can use the trawl velocity information to adjust warp length and vessel speed to compensate for underwater currents affecting proper trawl geometry.
Precise bottom tracking shows movement of the trawl in two directions along the bottom, a feature that can be very useful when trawling in steep slopes and in heavy side current. Comparing real-time trawl velocity and direction with vessel speed and direction over ground provides the operator with valuable information to make necessary corrections.
The unit uses broadband transducers and software defined electronics to reduce interference problems that plague other speed sensors. It generates, radiates and detects acoustic energy backscattered from water particles to provide a self-contained velocity measuring capability using advanced digital signal processing algorithms.
Other key features of the sensor include: integrated multi-function sensing elements for altimetry, depth, temperature, pitch and roll, low power consumption and attractive price.
Multi-Parameter Sensor
Marport’s new Multi-Parameter Sensor incorporates high performance conductivity, temperature and depth sensing elements designed to meet the demands of deepsea environmental monitoring.
The sensor measures the three parameters necessary to determine salinity, density and speed of sound. Data may be stored on the internal SD memory card (for standalone mode) or transmitted in real-time to the surface vessel via a wireless acoustic telemetry link. A Bluetooth short range wireless connectivity application enables programming of the sensing elements, internal logger and data extraction.
A depth rated pressure housing contains all on-board sensors, processing boards, data logger, acoustic telemetry and internal battery pack.
The compact instrument uses a Marport-developed inductive conductivity element. Digital sampling techniques ensure high accuracy and the robust construction ensures reliable performance. Temperature and pressure are measured using industry standard sensing elements including quartz pressure sensors.
Applications include speed of sound measurement to correct bathymetric measurements and accurate measurement of sound speed in the water column to improve data accuracy of acoustic net sensors.
In addition to being deployed on a trawl, it may be used as a discrete profiling instrument, installed on an underwater vehicle, or integrated into ocean observatories for remote sensing applications.
Oskar Axelsson, Marport executive vice president said: “Professional fishing companies are being faced with new challenges as well as new opportunities to positively impact their operations. We are proud to maintain a leadership position by offering advanced products to our customers.
“Our Software Defined Sonar product platform is a truly innovative approach to improving underwater acoustics, and it highlights Marport’s unique ability to differentiate our products over competitive offerings. We remain totally committed to providing the global commercial fishing industry with the most comprehensive product platform that enables operators to make better operational decisions, lower costs and increase their revenues.”
