The MOD and QinetiQ working together to provide Defence Test & Evaluation and Training Support Services

Underwater Radiated Noise

By measuring underwater radiated noise and analysing it in combination with onboard noise and vibration specialists, QinetiQ identifies the specific characteristics that contribute to a platform’s vulnerability to being detected by sonar.

Using fixed or transportable ranges, and on-board equipment, in-water noise can be assessed to determine the sources and characteristics of the far-field signature in representative operational states. Facilities can measure ships, submarines and other vehicles under all dynamic conditions to maximum speed – on the surface and submerged. Action is then recommended to reduce the platform’s vulnerability by maintaining or improving the signature. Comparing the results with the signature database will establish the significance of noise components and identify where remedial action is required.

Guidance can be provided on the optimum machinery configuration through the speed range, propeller performance – especially cavitation speed – and the effectiveness of noise reduction measures. This includes identifying the speed regions where system noise may peak in level.

  • Target Echo strength (TES): measurement, analysis and prediction of TES signatures to assess platforms for acceptance. In addition, a platform’s detectability is evaluated by active sonar, and advice and guidance on improving stealth performance is provided.
  • Noise and Vibration (N&V): deployment of an Onboard Ranging Officer enables interaction between the platform command and the Range, assisting acquisition of quality acoustic data for subsequent analysis and reporting. The onboard Hull Vibration and Monitoring Equipment (HVME) system aids identification of acoustic artefacts and assess high frequency noise if the Range is ambient limited. The team advises on effective use of signature monitoring systems, giving Ship’s Staff greater confidence of remaining undetected during operations.

The team has developed a set of proprietary calibration computation procedures and a bespoke suite of software to calculate calibration factors. The N&V team acts as the MOD’s acceptance expert on system harbour and sea acceptance trials.

Underwater Radiated Noise Services are available at: