Combined PAT algorithms for mobile multimedia satellite services

Next generation satellite services will offer high capacity links for multimedia applications. Mobile receivers for these future applications will use high gain antennas with a beamwidth of 5 degrees and smaller. These antennas require a precise pointing, acquisition and tracking (PAT) process to steer the antenna exactly towards the satellite direction. The channel characteristics at high frequencies, like fading and shadowing, seriously affect the steering algorithms. In the framework of SECOMS (Satellite EHF Communications for Mobile Multimedia Services) and ABATE (ACTS Broadband Aeronautical Terminal Experiment, both European ACTS projects) several field trials and service demonstrations have been performed for future wideband multimedia satellite services at higher frequency bands (20/30 GHz and 40/50 GHz). These experiments were performed using high gain antennas with various beamwidth in different scenarios and environments. This paper gives an overview of these experiments and describes the used antenna PAT algorithms. The measured propagation data allows the implementation of the effects of the land mobile satellite (LMS) channel in a detailed antenna pointing simulator