Comparison of Methods for Computing Spherical Wave Coefficients from Truncated Measurements

Abstract

Different approaches capable of mitigating errors caused by using truncated near-field patterns exist. In this work, the iterative approach, the direct least squares matrix inversion method, and the mixed FFT/Matrix inversion technique are compared in terms of their computation time and resulting truncation errors. The methods are also tested for robustness against noise in the measurement data. Singular value truncation is identified as a possible solution to high noise sensitivity of matrix methods and a tolerance factor expression for this truncation, based on the signal-to-noise ratio of used test data, is proposed.