Cumulant-Based Coherent Signal Subspace Method for Bearing and Range Estimation
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Research Article Cumulant-Based Coherent Signal Subspace Method for Bearing and Range Estimation Zineb Saidi1 and Salah Bourennane2 ´ ´ 3634, Institut de Recherche de Ecole Navale (IRENav), Ecole Navale, Lanv´eoc Poulmic, BP 600, 29240 Brest-Arm´ees, France Fresnel, UMR CNRS 6133, Universit´e Paul C´ezanne Aix-Marseille III, EGIM, DU de Saint J´erˆome, 13397 Marseille Cedex 20, France
1 EA
2 Institut
Received 27 July 2005; Revised 30 May 2006; Accepted 11 June 2006 Recommended by C. Y. Chi A new method for simultaneous range and bearing estimation for buried objects in the presence of an unknown Gaussian noise is proposed. This method uses the MUSIC algorithm with noise subspace estimated by using the slice fourth-order cumulant matrix of the received data. The higher-order statistics aim at the removal of the additive unknown Gaussian noise. The bilinear focusing operator is used to decorrelate the received signals and to estimate the coherent signal subspace. A new source steering vector is proposed including the acoustic scattering model at each sensor. Range and bearing of the objects at each sensor are expressed as a function of those at the first sensor. This leads to the improvement of object localization anywhere, in the near-field or in the far-field zone of the sensor array. Finally, the performances of the proposed method are validated on data recorded during experiments in a water tank. Copyright © 2007 Hindawi Publishing Corporation. All rights reserved.
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INTRODUCTION
Noninvasive range and bearing estimation of buried objects, in the underwater acoustic environment, has received considerable attention. Many studies have been recently developed. Some of them use acoustic scattering to localize objects by analyzing acoustic resonance in the time-frequency domain, but these processes are usually limited to simple shaped objects [1]. In the same way, Guillermin et al. [2] use the inversion of measured scattered acoustical waves to image buried object, but the applicability in a real environment is not proven. Another method which uses a low-frequency synthetic aperture sonar (SAS) has been recently applied on partially and shallowly buried cylinders in a sandy seabed [3]. Other techniques based on signal processing, such as time-reversal method [4], have been also developed for object detection and localization but their applicability in real life has been proven only on cylinders oriented in certain ways and point scatterers [5]. Furthermore, having techniques that operate well for simultaneous range and bearing estimation using wideband and fully correlated signals scattered from near-field and far-field objects, in a noisy environment, remains a challenging problem.
Array processing techniques, such as the MUSIC method, have been widely used for source localization. Typically, these techniques assume that the underwater acoustic sources are on the seabed and are in the far field of the sensor array. The goal then is to determine the directions of the arrival of the sources. These techniques hav
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