10039632In House Testing Capability for Towed Hydrophone ArraysClosedCollaborative R&DInnovate UKMSeis provide towed hydrophone arrays for use in noisy offshore environments to help mitigate against the harmful effects of industrial noise on cetacean species in compliance with guidelines from bodies such as JNCC, IBAMA, BOEM etc; whales, dolphins and porpoise. In order to do this effectively we require hydrophone elements that will respond to marine mammal vocalisations across the full frequency range, this is generally accepted as 1Hz-150 kHz. To prove this frequency response we test both newly manufactured and arrays returning from the field in a pool using a speaker with a controlled sweep through the entire frequency range. This can be seen as quite a subjective process as no figures are obtained from the test, we do, however, see it as the basis for an improved testing method. With our partner NPL we would like to quantify this response more accurately. The proposal is to provide better low frequency sound generation through amplifiers and specialist speakers. To create a methodology for elements situated along 10m of cable that can placed accurately and repeatedly for consistency of integrity and calibration against a known reference. This will involve the development of specific procedures and rigging designed around our array configuration. The rigging will take the form of measurable XYZ gantry to deploy reference and test hydrophones into the pool with ability to perform more accurate alignment for improved underwater measurement. Computational methods to understand how to implement and understand the results. This will hopefully lead to some basic computerised automation. In simple terms we will use a calibrated hydrophone to determine it's response to our various sound sources; this will then act as a reference so that we can then gain calibration readings for the array by comparison to the calibrated hydrophone device. This in turns provides the absolute sensitivity of the hydrophone which provide much reliable information of our arrays performance. In addition MSeis plan to use knowledge and instruction from NPL to create a variable frequency pistonphone type arrangement to test hydrophone element response at lower frequencies ideally 0-350 Hz which is hard to do in a relatively small pool. At the end of the project we will be able to test the integrity of all 4 hydrophone elements in an array. This will give our clients the confidence to prove detection capability of endangered species such as Northern Right Whale and Pygmy and Dwarf Sperm whales.