Numerical computation of the probability density of the phase error of the FFT-based digital interferometer

Although the phase error probability density function (pdf) of the FFT-based digital interferometer has been successfully de rived, the reliable numerical computation of the pdf presents practical difficulties. This paper provides a practical frame work for computing the phase error pdf involving the appropriate truncation of the infinite series embedded in the mathematical formula for the phase error pdf. As a corollary, it is shown that the easily computable von Mises probability density can be used to closely approximate the phase error pdf in the high signal-to-noise ratio regime. These results are useful for analyzing the performance of interferometric direction finding systems.