Sensitivity of the wave-number domain field separation methods for scattering

Abstract

The two-surface field separation technique for obtaining the sound field scattered from an object has been shown to be feasible for both the Cartesian and cylindrical coordinate systems [Cheng et al., J. Acout. Soc. Am. 97, 2293–2303 (1995)]. Investigations of the sensitivity of implementing these separation techniques to the measurement parameters and their errors will be reported. The results of this sensitivity investigation are helpful in deciding the accuracy of the far-field target strength results and designing experimental procedures and equipment that ensure accurate results. The separation and the spatial processing parameters that are considered include the distance between measurement points in each measurement surface, the aperture size of each measurement surface, and the distance between measurement surfaces. Recommendations for these parameters are made. Next the sensitivity to errors in the experimental geometry is explored. For the Cartesian coordinate system skew and curvature of the measurement surfaces caused the most significant errors. For the cylindrical coordinate system errors in the measurement cylinder radii and skew caused the most significant errors. In both coordinate systems the errors could not be effectively corrected with signal processing except for the skew in the case of the cylindrical coordinate system.