Analysis and improvement for measurement error of Ka-band communication satellite payload in-orbit test due to atmospheric fluctuation

This paper studies a method to improve the measurement accuracy of in-orbit test (IOT) for the Ka-band communication satellite payload. Since ground telemetry and command station of this satellite operates at low elevation, Ka-band atmospheric attenuation and fluctuation are much large. Due to lack of effective way to separate the influence of atmospheric attenuation, IOT processing has to employ the conventional method for many years, that is to say, tests need to choose sunny days and atmospheric attenuation is supposed to be fixed in this situation. However, this assumption degrades significantly measurement performance of the conventional IOT processing. To overcome this shortcoming, the paper proposes an improved IOT method, in which IOT test data is corrected more accurately after introducing two-channel-microwave-radiometer into IOT procedure to measure atmospheric attenuation of uplink and downlink along signal propagation path. Theoretical analysis for the measurement accuracy of the conventional method and the improved method are investigated in the paper, and comparisons for actual test data of these two methods are also provided, then IOT experiment result proves that the proposed scheme outperforms the conventional scheme remarkably.