Phase effects of ionospheric irregularities. Results of the Air Force Wright Aeronautical data processing effort

Data processing of Air Force Wright Aeronautical Laboratory flight test satellite signal measurements has been performed to illustrate the phase effects associated with ionospheric irregularities. Measurements are available at 250 MHz satellite signals traversing ionospheric heating induced irregularities, barium ion cloud irregularities, and polar and equatorial irregularities. For each of these environments displays of amplitude, phase difference standard deviation, phase difference histograms and phase power spectral density are given. The results of ionospheric heating measurements imply that underdense heating produces large scale irregularities with fluctuation levels that are conceivably larger than overdense heating fluctuations. The barium measurements from the CASTOR releases by Max Planck Institute in March 1979 near Peru show no barium associated phase effects. Because of the 275 km release altitude it is expected that the associated phase effects should be difficult to resolve. The phase difference histograms from the strong fading observed in the solar and equatorial measurements illustrate the importance of the non-Gaussian nature of the phase to communications. Binary phase-shift keyed (BPSK) irreducible error rates greater then minus ten to the 3rd power are predicted for these environments based upon their similarity with band-limited Gaussian noise.