A Study for an Adaptive Anti-Jamming Antenna for the User Receiver of the GEO Satellite Communication System

The separation angle between geostationary earth orbit (GEO) satellites tends to be smaller owing to the increasing demand of high-speed fixed satellite services. This will increase the interferences from adjacent satellites at the user receivers of the GEO satellite communication systems. The commonly very small aperture terminal (VSAT) used by user receivers of these systems has no capability to cancel jammers. The objective of this document is to present the study of an adaptive anti-jamming antenna to replace the traditional VSAT at the user receiver and improve the anti-jamming performance of a real GEO satellite communication system. In this study, we considered the characteristics of a fixed satellite service (FSS) and a GEO satellite communication system to design a square array (SA) of antennas that could replace the VSAT and meet the requirements of the system. The SA was divided into square sub-arrays (SSAs) and the linear constraint minimum variance (LCMV) algorithm was used to control the outputs of these SSAs to introduce a small gain in the directions of arrival (DOAs) of the jammers and guarantee the required gain in the direction of arrival (DOA) of the useful signal. We designed a simulation system to verify the performance of the adaptive anti-jamming antenna. In the simulations, we introduced two jammers at the user receiver from different DOAs. We simulated the performance of the uncontrolled antenna, and the degradation of the signal-to-jammer-plus-noise ratio (SJNR) due to the jammers was verified. After the antenna was controlled (by LCMV), the SINIR was improved and met the requirement. The results demonstrate that the adaptive anti-jamming antenna can replace the VSAT to fulfill the system requirements and cancel possible interferences.