| Antenna quivering is a physical phenomenon caused by unstable attitude of satellite. The phenomenon occurs periodically and affects the stability of communication seriously.Physical layer of satellite communication is affected most seriously by antenna quivering.In this paper, we studied the power control technology and synchronization algorithm in geostationary earth orbit (GEO) satellite system when antenna quivers.The communication system we studied is based on GMR-1 standard. The system offers the solid support for users when satellite properly functions. However, when facing the tremor of antenna, the scheme can't respond immediately and fail to make sure the system is under control. The paper discussed the power control and synchronization technology with antenna tremor in GEO satellite mobile telecommunication system. The main contents are as follows:1. Modeling of physical layer of GEO satellite mobile communication system under GMR-1 standard; introduced the basic norms and technical standards in communication.2. We established the satellite communication channel in antenna tremor condition. Then,we evaluated the channel according to traditional transmission theory and link design standard.The influence on the transmission and distribution characteristics of signal has been analyzed at last.3. We applied the GEO communication system combined with channel as simulation platform. Then we analyzed the influence of antenna tremor on transmission power, power control process and carrier synchronization.4. We put forward several improvement measures for each module to respond the emergency. A novel frequency synchronization algorithm based on Chirp detection has been proposed. The algorithm has properties of wide detection range and adaptability. We also presented a power detection algorithm based on ARMA model. The algorithm can detect the time point of tremor and control system transmitting power normally. |
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