High Data Rate Satellite Communications Research Articles

An Activity Report on Electromagnetic Wave Sensing in Random Media and High Data Rate Satellite Communications, Pursued in a Research Laboratory

The following two kinds of researches are conducted in my laboratory: (A) electromagnetic (EM) wave theory with application to sensing, imaging and material estimate, and (B) high data rate satellite communications systems. Each research has five subjects and this paper addresses four subjects, which are (A-1) Effective parameters of a medium containing many particles, (A-2) Radar characteristics of a body surrounded by a random medium, (A-3) Statistical methods for measuring ocean waves in satellite altimetry, and (B-4) Atmospheric turbulence effects on high data rate satellite communications. Here A and B in parentheses indicate above two researches, respectively. To solve these subjects the author has proposed fundamental and original methods and thereby obtained many interesting results to scientists and engineers. General remarks are made on the results in this paper.

Ka-band multibeam active phased array antenna

The high data rate and global satellite communication systems are expected to be an important technology to the social and economic activities in this century. The experimental high data rate satel...

Trans-Pacific Demonstrations (TPD): remote astronomy demonstration and results

In 1993, a proposal at the Japan-US Science, Technology, and Space Applications Program (JUSTSAP) workshop led to a subsequent series of satellite communications experiments and demonstrations, under the title of Trans-Pacific High Data Rate Satellite Communications Experiments. The first phase of this was a joint collaboration between government and industry teams in the United States and Japan that successfully demonstrated distributed high definition video (HDV) post-production on a global scale using a combination of high data rate satellites and terrestrial fiber optic asynchronous transfer mode (ATM) networks [1-3]. This was followed by the Phase-2 Internet Protocol (IP) based experiments and demonstrations [4-7] in tele-medicine and astronomical distance education, using another combination of two high data rate satellites and terrestrial fiber optic networks. This paper describes the Phase-2 remote astronomy experiment in detail. This experiment established a heterogeneous ground- and space-based network between Japan and several sites in the US, which was used by students, scientists, and educators to provide real-time interaction and collaboration with the 14-inch Telescopes in Education (TIE) telescope and associated data archive. The remote astronomy activity demonstrated collaborative observation and distance education at multiple locations around the globe and the transparent operations of distributed systems technologies over a combination of broadband satellites and terrestrial networks. The use of Internet Protocol related technologies allowed the general public to be an integral part of the exciting activities, helped to examine issues in constructing a global information infrastructure with broadband satellites, and afforded an opportunity to tap the research results from the (reliable) multicast and distributed systems communities. In this paper, we describe the network infrastructure at both the technical and user levels, review the operation of the experiment, and summarize our lessons learned. We find that such networking, while still somewhat complex to construct on highly distributed scales, can provide educators and students with a unique collaborative environment which greatly enhances the educational experience.

Precision waveform shaping and precompensation for high data rate space communications systems

This paper studies a memory-based pulse shaping and traveling wave tube precompensation technique applied to high data rate satellite communications. Baseband I and Q waveforms are synthesized from data stored in a distributed arithmetic architecture. The waveforms are adjusted to minimize intersymbol interference spectral bandwidth and traveling wave tube distortion. We evaluate its performance in a simulated bi-phase shift keying (BPSK) link. The results show that memory-based precompensation has great potential to improve link performance.