Acoustic remote sensing research on marine sediments is carried out with very low frequency seismic sensors in order to determine the main characteristics of these sediments over very large ranges of penetration depths, and with high frequency sonars to image the sea bed and detect objects lying there. But there is still no technique for exploring the first few metres of depth in sediments, yet there are a number of underwater exploration applications where this range is important:
- study of the sediment processes and dynamics, and their geotechnical properties
- safety of pipelines burial
- archaeological research
- retrieval of lost cargo or toxic waste
The proposed exploration method should be able to yield a precise description of sediments down to about 20 metres, and to detect and classify embedded rocks and man-made objects within this depth range. It should lead to the definition of a quasi-monostatic system.
The principle of this method is to combine several modern techniques: - the use of parametric arrays to obtain simultaneously low frequency, large bandwidth, and fine spatial resolution,
- application of theories of scattering by objects and by the bottom to predict the features of echoes and reverberation,
- signal processing and near-field linear array processing to increase the echo-to-noise and echo-to-reverberation ratio,
- the detection and classification of buried objects.
The consortium comprises partners that have considerable experience in these activities. LUT has many years of expertise in designing and operating parametric arrays. TNO-FEL has expertise in tank and sea experiments, and in array signal processing. DIBE has concentrated on various new signal processing methods. AESN, TS.ASM and SACLANT, are well-known for their experience in every aspect of sonar.
The main area of the MAST III programme covered by this proposal is C.1. But it also has an impact on areas A.1, A.3, B.1, B.2.
Funding SchemeCSC - Cost-sharing contracts
LE11 3TU Loughborough
2509 JG Den Haag ('S-gravenhage)
19138 La Spezia