Title :
Spatial smoothing and minimum variance beamforming on data from large aperture vertical line arrays
Author :
Tran, Jean-Marie Q D ; Hodgkiss, William S.
Author_Institution :
Dassault Electron., Saint-Cloud, France
fDate :
1/1/1993 12:00:00 AM
Abstract :
Various approaches to the beamforming of data from large aperture vertical line arrays are investigated. Attention is focused on the conventional beamforming problem where the angular power spectrum is estimated, in this case by the adaptive minimum variance processor. The data to be processed are 200 Hz CW transmissions collected at sea by a 900 m vertical line array with 120 equally spaced sensors. Correlated multipath arrivals result in signal cancellation for the adaptive processor, and spatial smoothing techniques must be used prior to beamforming. The processing of subapertures is proposed. Full aperture and subaperture processing techniques are used on the 200 Hz data. Multipath arrivals are found to illuminate only parts of the array, thus indicating that the wavefield can be highly inhomogeneous with depth
Keywords :
acoustic arrays; acoustic signal processing; oceanographic techniques; underwater sound; 200 Hz; CW transmissions; adaptive minimum variance processor; adaptive processor; angular power spectrum; correlated multipath arrivals; minimum variance beamforming; sea; signal cancellation; spatial smoothing; subapertures; vertical line arrays; Apertures; Array signal processing; Covariance matrix; Laboratories; Narrowband; Sensor arrays; Signal processing; Smoothing methods; Spatial filters; Time factors;
Journal_Title :
Oceanic Engineering, IEEE Journal of