1993 Fiscal Year Final Research Report Summary
A STUDY ON AN EXPERT SYSTEM FOR PREDICTION OF RADIOWAVE PROPAGATION REQUIRED FOR BROADCAST AND RADIO COMMUNICATION SYSTEMS
| Project/Area Number |
04650292
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
電子通信系統工学
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| Research Institution | KAGOSHIMA UNIVERSITY |
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Principal Investigator |
ITO Shiro KAGOSHIMA UNIVERSITY, FACULTY OF ENGINEERING, PROFESSOR, 工学部, 教授 (80232445)
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| Project Period (FY) |
1992 – 1993
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| Keywords | Ghost-image disturbance / Flutterring disturbance / Disturbance due to buildings / Disturbance due to a helicopter / Mobil communication / Field-strength in built-up areas / Delay spread / Expert system |
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| Research Abstract |
Three kinds of fundamental prediction methods of radiowave propagation are studied, which are to be incorporated into an expert system required for design and maintenance of broadcasting and communication systems. Those prediction methods are as follows ;
(1)The first method is for prediction of the disturbance to television reception due to buildings. Reflection and shadowing effects due to buildings are calculated by the use of the aperture-field method and the Fresnel approximation for analysis of modelled buildings, which are consisted of rectangular metal plates. A computer program is prepared to predict the grade of the disturbance and disturbed areas due to the interesting buildings.
(2)The second method is for predicting the field-strength fluttering at television reception caused by an aircraft such as a helicopter. A helicopter is converted to an equivalent model for caluculation of radiowave scattering, which is consisted of rectangular metal plates and a rotating thin cylinder. The applied methods for analysis are almost the same as in the above method except using the Fraunhofer approximation in this case. A computer program is provided for predicting the gradeof the fluttering disturbance.
(3)The third method is for prediction of propagation in built-up urban areas for mobil communication systems. Buildings are modelled as a combination of rectangular plates as in the first method. Shadowing and single and double reflections are taken into account. The prepared computer program provides predicted propagation factors pertinent to mobil communications, such as field-strength, frequency shify by the Doppler effect and delay spread.
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