An adaptive beam control technique for diversity gain maximization in LEO satellite to ground transmissions

Abstract

The earth observation missions have improved its sensor performance, it results in a huge amount of data to be stored and transmitted to a ground station. Although, satellite to ground transmitter had been usually used X band, migration to Ka band has been studied in recent years for broadband transmission. Relative to X band, higher frequency has severe atmospheric effects, site diversity is one of the popular technique to mitigate rain attenuation. However, if Signal to Noise power Ratio (SNR) is different between receivers because of receiving antenna gain and rain attenuation, diversity gain decreases. This paper proposes novel beam controlling method to improve SNR performance for satellite to ground transmission. The proposed method estimates SNR in each of candidate transmitting antenna boresight, and update boresight in order to be equal SNR between receivers. Simulation results show that, proposed method improves SNR especially at a low elevation angle.