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Milestones

Research and Development

1964: The Concept

Butement and d'Assumpcao (Australian Defence Scientific Services Report RD/64 June 1965) entitled Long Range Submarine Detection) outlined the original directional sonobuoy concept. Butement originally envisaged a cruciform array; d'Assumpcao later modified the configuration to 5 radial arms.

The original proposal included both passive (listening) and active detection (explosive echo-ranging, using an underwater charge to create a loud noise whose echo from the submarine is picked up by the sonobuoy). Signals are sent to the aircraft where they are processed to infer the bearing and identity of their source.

1964-1972: Feasibility study

Background research:

Submarine noise levels
Background noise levels in Australian waters
Sound propagation in the sea

Theoretical studies on system specifications:

Detection range required
Array geometry
Compass accuracy required
Acoustic bandwidth

Sea tests in South Australia to confirm design and performance

Studies reveal that, for the potential enemy submarines then in service, the Barra Sonobuoy would be more effective in passive detection (listening for submarine noises) than active detection (explosive echo-ranging). The decision was taken to set aside active detection unless submarine emitted noise dropped substantially.

Engineering studies on:

Array deployment
Hydrophone design
Data transmission
Compass

Testing at Kilsby’s Hole in South Australia
Sea trials off Jervis Bay in New South Wales of an experimental buoy

Sea trials off Jervis Bay of a prototype buoy

Engineering Development and Production

1972: Project Definition

The project definition was contracted to five companies:

Amalgamated Wireless Australasia (AWA) prime contractor - electronics and compass
Electronic Systems and Management Services (ESAMS) - system design and project control
Commonwealth Aircraft Corporation (CAC) – mechanical structures and air deployment
Plessey – hydrophones and battery
Cable Makers Australia (CMA) - suspension cable

1973: Full Scale Engineering Development

The engineering development involved the same five companies who worked on the project definition and established a feasible hardware design.

1974-1981: Production Development

Individual contracts were let to the five companies and, under Department of Defence project management, culminated in the manufacture of production prototypes which were extensively tested for design approval of the Barra Sonobuoy.

1975: Australia and UK agree to joint development and manufacture

Under this agreement, Australia designed and manufactured the Barra sonobuoy and the UK designed and manufactured the Barra airborne receiver and processor. The acoustic processor, designated the AN/AQS-901, was manufactured by Elliot Bros (later GEC-Avionics), in Rochester, UK . This processor has flown in both the UK Nimrod and RAAF AP-3C aircraft.

Newer generation acoustic processors are currently flying in both the RAAF AP-3C and RAN Sikorsky SH-70-B ASW Helicopters.

1977-1982: Initial Production and Reliability Growth

This period saw the establishment of a production facility capable of manufacturing high reliability sonobuoys. This project was led by AWA along with the other four companies. The Barra Sonobuoy entered operational service with the RAF in mid 1980 and the RAAF in early 1981.

This led to many more production contracts.

1997: DSTO-Thales-RAN Alliance

DSTO, RAN and Thales enter into an agreement to exchange information, to conduct collaborative research and development on sonar systems technology and trends and to undertake collaborative R&D in sonar system technology . Examples of useful collaborative programs, some supported by the Australian Defence Organisation "Capability Technology Demonstrator" (CTD) program include: