Angle-of-arrival Fluctuation at Large Zenith Angles
大天顶角的到达角起伏

Based on the modified Kolmogorov spectrum and quadratic structure function approximation,the expressions are derived for the variance and power spectrum of the angle-of-arrival fluctuation at large zenith angles.The validity of the derived expression extending into the any zeniths is evidenced by the simulations.When the receiving aperture is much larger than the scattering disk scale,the aperture-smooth effect is remarkable and the derived variance approximates the result given by weak-fluctuation theory for any zenith;when the receiving aperture is much smaller than the scattering disk scale,the low-pass filter effect of the scattering disk scale is dominating and weak-fluctuation theory is valid only for small zeniths.In the cases that D<25 cm,the derived result is in good agreement with conventional weak-fluctuation theory for zenith angles less than 50 to 70 deg,but departure from weak-fluctuation theory is predicted by the new models for larger zenith angles.