Making security sweeping faster and more accurate

rotv FOCUS instrumentation sas sonar engineering defence

Applied Signal Technology has chosen the MacArtney A/S Focus-2 ROTV as platform for the fastest, most accurate towed SAS (synthetic aperture sonar) system yet - the Prosas Surveyor. This new towed sonar system combines the superior flight characteristics and data output capacities of the Focus 2 ROTV with the high resolution wide sweep qualities and output processing of AST's SAS sonar system.

Knowing what is underwater can be a matter of national security

Navies have always required information on the underwater environment, from knowing how deep the water is to knowing where mines are located on the sea floor. Increasing global and national security issues now mean that knowing exactly what is under the water can be a matter of national security, particularly in sensitive areas or on special occasions.

Many sectors are dependent on detailed sea bed information

Other industries are also reliant upon accurate up-to-date information on underwater conditions. Cable and pipe-laying industries and the oil and gas sector need high quality data.

As the information demand increases, and the scope of required data expands, the focus is on combining accuracy with optimal ship and scan time.

A new towed real time sonar system is created

Traditionally, SAS sonar systems have been mounted on AUV's, but these vehicles have their limitations. Current and tide can render AUV positioning inaccurate, require high levels of power from AUV motors, and cannot be accessed real time.

Sweep paths on AUV's are pre-programmed, and the positioning accuracy of any finds they make have a margin of error depending upon the effect water movement has had on their position.

To meet the growing demand for rapid, accurate data, MacArtney A/S and AST (Applied Signal Technology) created the Prosas Surveyor, a new system that provides accurate real time data from the sea bed. Real time data allows operators to make on the spot decisions about further investigation or possible threat, saving time and ensuring optimal safety. This is particularly relevant in situations where an area is being swept for mines or other underwater threats to security.



Unmatched accuracy and stability for precise data

Accurate positioning and stability are critical when gathering detailed underwater information. Where other systems can be affected by currents and water movement, the Focus 2 has a unique stabilising platform that eliminates the effects of water movement, eliminating inaccurate or defocussed output.

The SAS system allows for any items of interest to be geographically referenced in their exact position and further investigated or mapped for later inspection. Combined with AST's CAD/CAC software that automatically records important information, it is possible to compare real time data with previous sweep information. Any changes or new objects can be immediately spotted and acted upon, or monitored over several sweeps. Pre-existing objects can be ruled out, allowing operators to concentrate on potential threats.

Faster sweep saves time and money

Towed vehicles can operate at twice the speed possible with AUV's. The Prosas Surveyor can be operated at speeds of up to 10 knots, dramatically reducing the ship time necessary to complete a mission. The SAS sonar by AST processes clear, high definition across the entire broad sweep, reducing the number of sweeps required.

The Focus-2 ROTV can carry a wide range of sonars and sensors and handle information from the entire array of sensors in one sweep, eliminating the need to re-sweep the same area for additional information. The integrated system, the Focus 2 multiplexer, handles information from the range of sensors installed on the vehicle and transmits the data to the surface via a fibre optic telemetry system.

A wide range of potential uses

The first Prosas Surveyor system has been specially designed for shallow water surveys, ideal for port security. The system can also be used in deeper waters for a wide range of applications, including pipe-laying, oil and gas, mapping and surveying.

The Prosas Surveyor consists of:

  • Focus 2 Remotely Operated Towed Vehicle (ROTV)
  • Focus 2 top side control panel
  • Sonar arrays and electronics
  • Prosas Software
  • Inertial navigation
  • Winch
  • Power pack
  • Minescout CAD/CAC database


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