A new algorithm which associates (Multiple Signal Classification) MUSIC with acoustic scattering model for bearing and range estimation is proposed. This algorithm takes into account the reflection and the refraction of wave in the interface of water-sediment in underwater acoustics. A new directional vector, which contains the Direction-Of-Arrival (DOA) of objects and objects-sensors distances, is used in MUSIC algorithm instead of classical model. The influence of the depth of buried objects is discussed. Finally, the numerical results are given in the case of buried cylindrical shells.

The main target of Array processing is to estimate the bearing and range of sources or objects radiating in a medium of propagation [

In this letter, we propose a new algorithm for bearing and range estimation of buried objects in underwater acoustics. The approach is based on MUSIC combined with the acoustic scattering model [

The remainder of the letter is organized as follows. Section

Throughout the paper, lowercase boldface letters represent vectors, uppercase boldface letters represent matrices, and lower and uppercase letters represent scalars. The symbol “

Consider a linear array of

The wavefront is assumed to be plane when the objects are far from the array. We use MUSIC algorithm to estimate the angle

We assume an object is buried in the sediment

Geometry configuration of the buried object.

the incident plane wave,

the reflecting plane wave,

the transmitted plane wave diffused by the object.

The pressures in the water and the sediment are given by five unknown parameters

We consider the case of infinitely long elastic cylinder shell. The first sensor of the array

Find an initial estimation of

Fill the matrice

Estimate the spectral matrix

Calculate sources spectral matrices by

Compute the average of the spectral matrices

Caltulate

Use the eigenvectors

Calculate the focused spectral matrix:

Estimate the number of objects by AIC or MDL [

Calculate the spatial spectrum of MUSIC method for estimating bearing and range of buried objects:

In sandy sediment, the attenuating effect of suspended material is negligible. Conversely, the attenuating effect of the sediment is significant. It can be reported in dB/cm/kHz since the examination of attenuation yielded a linear dependency with frequency. The attenuation coefficient of common sand [

The parameters of the simulations are defined as follows:

The array is placed in the water with the hight

Localization of cylindrical shells.

When the cylindrical shell is deeply buried (20°, 0.3 m), we vary the interface of water-sediment for each

The results obtained (see Figures

Std between expected and estimated bearings.

Std between expected and estimated ranges.

In this paper, we propose a new algorithm based on MUSIC associated with acoustic scattering model for bearing and range estimation of buried objects. There is an analogy of the water-sediment interface by combining with the reflection and the refraction of wave in the model. A new directional vector, including the information for bearing and range estimation, is employed instead of the plane wave model in the MUSIC algorithm. The results of buried cylindrical shells are significantly accurate. Then we study the influence of the depth. The results show that beyond a certain depth, the attenuation becomes too large and therefore the objects cannot be detected or located neither.