title: Local propagation speed constrained estimation of the slowness vector from non-planar array observations.
abstract: The estimation of the slowness vector of infrasound waves propagating across an array is a critical process leading to the determination of parameters of interest such as the direction of arrival. The sensors of an array are often considered to be located in a horizontal plane. However, due to topography, the altitudes of the sensors are not identical and introduce a bias on the estimate if neglected. However, the unbiased 3D estimation procedure, while suppressing the bias, leads to an increase of the variance. Accounting for an a priori constraint on the slowness vector significantly reduces the variance and could therefore improve the performance of the estimation if the introduced bias by incorrect a priori information remains negligible. This study focuses on measuring the benefits of this approach with a thorough investigation of the bias and variance of the constrained 3D estimator, which is not available in the existing literature. This contribution provides such computations based on an asymptotic Gaussian approximation. Simulations are carried out to assess the theoretical results both with synthetic and real data. Thus, a constrained 3D estimator is proposed yielding the best bias/variance compromise if good knowledge of the propagation wave speed is accessible.
authors.affiliation: CEA, DAM, DIF, F-91297 Arpajon, France.
authors.forename: Adrien
authors.initials: A
authors.lastname: Nouvellet
authors.affiliation: Telecom ParisTech, Institut Telecom, Centre National de la Recherche Scientifique, Laboratoire Traitement et Communication de l'Information, 46 rue Barrault, 75634 Paris Cedex 13, France.
authors.forename: François
authors.initials: F
authors.lastname: Roueff
authors.affiliation: CEA, DAM, DIF, F-91297 Arpajon, France.
authors.forename: Alexis
authors.initials: A
authors.lastname: Le Pichon
authors.affiliation: Telecom ParisTech, Institut Telecom, Centre National de la Recherche Scientifique, Laboratoire Traitement et Communication de l'Information, 46 rue Barrault, 75634 Paris Cedex 13, France.
authors.forename: Maurice
authors.initials: M
authors.lastname: Charbit
authors.affiliation: CEA, DAM, DIF, F-91297 Arpajon, France.
authors.forename: Julien
authors.initials: J
authors.lastname: Vergoz
authors.affiliation: Centre National de la Cartographie et de la Télédétection, NDC-TN, BP 200, 1080 Tunis Cedex, Tunis.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Kallel
authors.affiliation: Centre National de la Cartographie et de la Télédétection, NDC-TN, BP 200, 1080 Tunis Cedex, Tunis.
authors.forename: Chourouq
authors.initials: C
authors.lastname: Mejri