Correlation analysis of the fading of radio waves reflected vertically from the ionosphere

Abstract

The correlation analysis of Briggs et al. (1950) and phillips and Spencer (1955) has been applied to the fading of radio waves reflected from the E and F-regions of the ionosphere, observed at three closely spaced receivers. Histograms are presented showing the size of the characteristic ellipse of the radio diffraction pattern formed on the ground, and also the axial ratio and the direction of the major axis of this ellipse. Results are presented which show the importance of random changes in the pattern relative to pure drift in producing fading. Corresponding results from other parts of the world are reviewed briefly. Drift velocities found by correlation analysis are compared with those found by the simple time-delay method, and it is shown that the errors in the time-delay method are considerable. A comparison is made between the method of calculation used by Briggs et al. and the six-point method of Yerg (1955); the former is to be preferred.