Elevation Angle of Quasi-Zenith Satellite to Exceed Limit of Satellite Visibility of Space Diversity which consisted of Two Geostationary Satellites

The paramedic in the moving ambulance sends the moving picture data to the doctor in the hospital via the communications satellite. However, when an ambulance runs inside a city, a radio wave to the communication satellite is blocked and as a result the moving picture data sometimes freeze. A value of the satellite visibility by the space diversity which consists of two geostationary satellites was acquired by simulation based on the hemispherical urban space data measured by a fish-eye camera in each city of Japan. From these simulation results, it was found that there was a limit in the satellite visibility by the space diversity. It is known that the satellite visibility is more improved by the quasi-zenith satellite. The elevation angle condition of the quasi-zenith satellite which exceeds the limit of the satellite visibility of two geostationary satellites was acquired. This elevation angle was compared between each city of Japan. It became clear that more than 68 deg of an elevation angle of the quasi- zenith satellite is necessary to exceed the limit of satellite visibility of two geostationary satellites.