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oai:www.ideals.illinois.edu:2142/69288 2023-07-11 col_2142_5131 col_2142_8888 com_2142_5130 com_2142_8887 com_2142_234

Franke, Steven John 2014-12-15T19:04:48Z 2014-12-15T19:04:48Z 10000-01-01 1984 1984 Experimental measurements of signal level fluctuations (scintillation) on VHF and microwave signals from two geostationary communications satellites are studied in detail. The signals were recorded at an equatorial location which is almost directly beneath the satellites. The scintillation is caused by refraction and diffraction of the signals by variations of the refractive index in the F layer of the ionosphere. This study is directed toward using the observed multifrequency scintillation to remotely sense the characteristics of the ionospheric irregularities. This is done by considering both statistical and deterministic models for the scintillation producing irregularities. The models are combined with existing propagation theory using analytical and numerical simulation techniques in order to predict the spatial and temporal characteristics of the multifrequency scintillation. Comparison with the observations is used to verify the models. Extensive use is made of numerical simulation. This makes it possible to study both "weak" and "strong" scintillations which occur simultaneously on the microwave and VHF frequencies, respectively. In all cases, the models are chosen to be consistent with results from other remote sensing techniques and in situ measurements. Geophysical implications of the results are discussed in light of what is known about equatorial irregularities from previous experimental and theoretical studies. Made available in DSpace on 2014-12-15T19:04:48Z (GMT). No. of bitstreams: 1 8502144.pdf: 7559157 bytes, checksum: 4c9845d5daa2facd1b8fe3588b7079eb (MD5) Previous issue date: 1984 Embargo set by: Seth Robbins for item 69454 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs U of I Only 275 p. Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1984. http://hdl.handle.net/2142/69288 (UMI)AAI8502144 Engineering, Electronics and Electrical Remote Sensing Remote Sensing of Irregularities in the Equatorial Ionosphere Using the Radio Scintillation Technique text Dissertation Ph.D. Electrical Engineering Electrical Engineering University of Illinois at Urbana-Champaign