| 摘要 |
PURPOSE:To eliminate the effect of attenuation due to rainfall and to simplify equipment for an earth station and a satellite, by using a signal from the earth station not effected by the rainfall, and detecting an error at the orientation of a satellite antenna beam. CONSTITUTION:The signals from the earth stations 21-24 are received at a satellite 30. First, the signal levels of two frequencies f1, f2 from the same earth station are compared to discriminate the presence/absence of attenuation due to the rainfall. The amount of change from a normal value is detected as to the signal levels from plural earth stations not effected by the rainfall. The error at the antenna beam orientation of satellite antennas is detected from this value, and the position of each earth station and the cubic directivity or cross polarized wave characteristics of the satellite antennas. |
