{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/69288"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/69288","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Remote Sensing of Irregularities in the Equatorial Ionosphere Using the Radio Scintillation Technique","abstract":"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.","abstract_html":"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.","abstract_has_math":false,"creators":["Franke, Steven John"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Electrical Engineering","degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2014,"date_issued":"2014-12-15T19:04:48Z","date_published":"2014-12-15T19:04:48Z","updated_at":"2026-07-22T22:26:00Z","subjects":["Engineering, Electronics and Electrical","Remote Sensing"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["(UMI)AAI8502144"],"render_values":[{"text":"(UMI)AAI8502144","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/69288","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Franke, Steven John"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2014-12-15T19:04:48Z","10000-01-01","1984"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Electrical Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Engineering, Electronics and Electrical","Remote Sensing"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/69288","(UMI)AAI8502144"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["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). 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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). 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