Acoustic

Pipe Noise Maker

	Pipe Noise Maker

The baseline acoustic generator supplied with the Dyad Influence Sweep is a four tube Pipe Noise Maker (PNM) able to produce a shiplike acoustic coverage from low frequency through the audio frequency to ultrasonic. The PNM is a water driven, inexpensive, consumable item with an operational life of approximately 60 hours.

Programmable Acoustic Generators

Against modern mines, the two programmable Acoustic Generators (AAGs) are available, the AAG and the IAAG. Both these state-of-the-art acoustic generators provide multiple stable line structures, an increased speed range, and programable output spectrum. They are water driven turbine powered acoustic generators and can be integrated with any sweep system. Optimum spectral structure and spatial relationship is provided by employing two generators in a sweep, one midships, and one aft to emulate propeller blade rate and hull resonances. A single acoustic generator can be identified as a point source by a mine conducting passive ranging.

Australian Acoustic Generator (AAG)

Infrasonic Australian Acoustic Generator (IAAG)

AAG

The AAG produces a shiplike, broadband acoustic output from the infrasonic to the ultrasonic, with multiple stable line structure. Algorithms loaded to an onboard processor enable the programming of multiple tonals and the AAG is independent of external sources for either power or control. The system can be readily deployed by a wide range of vessels, including remote control drones.

IAAG

While the AAG produces very good warship emulation up to destroyer size and is able to emulate smaller merchant ships below 30 thousand tonnes, there is a capability requirement for sweeping in Mine Setting Mode (MSM) against the large number of existing obsolescent acoustic mines and for sweeping in Target Setting Mode (emulation) for modern mines targeted against large warships and large merchant ships.

The IAAG has two hydraulic vibrator sources (AAG technology) of back to back configuration, driving two acoustic pistons each of 750mm diameter. The IAAG fundamental frequency range is 5Hz to 40Hz producing 180dB and above (re 1uPA @ 1m).

Output Manipulation

The output control algorithm for a particular mission can be selected and downloaded to the onboard electronics module immediately prior to deployment. Alternatively, algorithms can be downloaded remotely during the mission through the AAG/IAAG Sweep Tracker Monitor System (STMS). The algorithm determines the energy distribution and resulting spectral shape.

Alternative programs can be loaded during deployment from a RIB via the programming box and a remote download cable at the surface.

Go to Australian Minesweeping News for further information on the IAAG.

Contact Details

For further information relating to mine countermeasures, please contact the General Manager Mine Countermeasures,
Jack Byrnes
ADI Limited
Building 314, Level 1
Garden Island NSW 2011

Tel: +61 2 9562 2991
Fax: +61 2 9562 2988
Email: jack.byrnes@adi-limited.com