Optimization of Satellite Communication Link by Digital Beamforming in Ground Stations

摘要

Satellite ground stations for LEO and GEO satellites are installed with antennas of size of several meters' parabolic dishes. Due to advances in the field of space communication, certain deficiencies of these antennas are becoming significant which are not important previously regarding their mechanical complexity, network efficiency, flexibility and high setup and maintenance cost. In the context of these, it is the need of hour to research alternative technologies to cope with these challenges. This paper explores the concept of intelligent ground stations, various adaptive array processing algorithms for antennas and discusses the feasibility of utilizing digital beam-forming techniques to improve the performance of ground stations for satellite communication link. Digital beam-forming utilizes the Adaptive Array Signal Processing (AASP) algorithms at the base band level. The adaptive ability of these signal processing algorithms makes the antenna smart. Because these antennas have the ability to track the interference and automatically adjust the antenna patterns i.e. null in the interference direction and provide gain in the desired signal direction. This activity improves the SINR (Signal to Interference Ratio). Moreover; antenna mechanical steering is replaced with the electronic steering which is a huge advantage in terms of cost and maintenance. AASP techniques provide the system flexibility due to its implementation at the base band level. This paper discusses feasibility of various algorithms used in the domain of AASP by targeting the application of smart ground stations in satellite communications. LEO satellites ground stations make use of huge parabolic antennas e.g. 10m diameter for telemetry and data downloading. Such type of setup raises the issues of mechanical wear and tear, low network efficiency, no flexibility for future missions, high maintenance and setup cost. These issues are mitigated by evaluating the AASP techniques in antennas of earth