A Semi-Analytical Target Strength Model for Active Sonar Performance in Realistic Propagation Conditions
conference paper
Propagation and sonar performance are modelled by TNO’s ALMOST program, already being developed since the Eighties. It models propagation between sonar and target based on ray theory, including effects of sediment bottoms, reverberation and ambient noise. Moreover, antenna directivity (beam forming) and signal processing are modelled, resulting in operational detection probabilities, and time signals (including envelopes). For realistic target echo modelling, ALMOST has recently been extended with an efficient semi-analytical model for Target Strength (TS). This model is based on a summation of the responses of the triangular grid elements that represent the outer and inner surfaces of the target structure, including the effects of their material properties and thicknesses on the reflection and transmission coefficients. The acoustic response of each triangle is modelled analytically by a Fraunhofer approximation. The calculated response is fed into ALMOST, which calculates the multi-path reflection. Examples are given for the TS of a rigid sphere and a generic submarine in realistic propagation conditions. The submarine geometry from the 2003 BeTTSi TS model benchmark study has been used. The calculations are performed for a wide band LFM pulse. Matched filter output from ALMOST, with high range resolution, demonstrates the effects of the propagation conditions on the effective Target echo Strength.
TNO Identifier
223791
Source title
Proceedings of the Eight European Conference on Underwater Acoustics - 8th ECUA, 12-15 June 2006, Carvoeiro, Portugal
Editor(s)
Jesus, S.M.
Rodriguez, O.C.
Rodriguez, O.C.
Files
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