Adaptive Antenna Systems for Satellite Communications and Navigation

Abstract

The performance of satellite communication and navigation systems can significantly be improved by the deployment of adaptive antennas on the satellite and in the user terminals. The adaptation of the antenna characteristics to the requirements of the transmission channel is carried out mainly through the use of arrays in conjunction with digital beamforming. In satellite navigation, adaptive antennas are considered as key technology in developing robust GNSS receivers for the detection and suppression of intended and unintended interference (spoofers, repeaters) and multipath signals. For precise positioning, multibeam antennas with individual beamforming and steering, side-lobe suppression, and nulling are of special importance. In combination with appropriate algorithms and methods for direction-of-arrival estimation (DOA), attitude determination, array and signal processing they are particularly suitable for safety-critical areas of navigation, such as safety-of-life applications (SoL). In satellite communications, high gain and precise tracking of the antennas are the decisive factors for the transmission of high data rates and a corresponding quality of services. Especially at high frequencies like Ka-band, digital beamforming reaches its limits due to the large number of antenna elements that must be individually equipped with transmission and/or receiver modules. The dense packaging often leads to nearly unsolvable thermal problems. To realize the high gain with a manageable number of antenna elements, a combination of reflector and feed array with MEMS switches and digital beamforming has been developed. After a short presentation of DLR, the talk will give an overview of the activities and projects in the Antenna Group of the Institute of Communications and Navigation. Future challenges and plans for the development of new concepts and demonstrators will be presented.