IONOSPHERIC REFRACTION EFFECTS ON THE DOPPLER SHIFT OF RADIO TRANSMISSIONS FROM ARTIFICIAL EARTH SATELLITES.
TEXAS UNIV AUSTIN DEFENSE RESEARCH LAB
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It is shown that ionospheric contributions to the received Doppler shift may be expressed in terms of powers of the inverse of the transmission frequency, where the first, second, and third order terms are of significance. The origin of each of these refraction errors is discussed. Faraday rotation is shown to be closely related to the second order ionospheric refraction error. A theoretical ionospheric refraction error computation program was instrumented on an IBM 1620 digital computer. For a spherically symmetrical ionosphere, results of the theoretical error computation are presented and these results indicate that the magnitude of the third order ionospheric refraction error may be considerably greater than that of the second order errors. Four-frequency Doppler data received from TRANSIT satellites at TRANSIT Station 002 in Austin, Texas, were analyzed in order to determine the frequency dependence of the measured ionospheric refraction error. Some interesting results of ionospheric refraction error measurements from TRANSIT IV-A data are presented and discussed. A theoretical distribution function which may be used to extrapolate ionosphere vertical radio sounding data to heights above h sub max, the height of maximum electron density of the F2 region, is presented. Models of electron density distribution for the upper ionosphere are presented and compared. Author
- Atmospheric Physics
- Radiofrequency Wave Propagation