Satellite Communication Overview of the Technology & the Antenna System Part IV

Key Issues

Looking ahead of 1990’s, one could observe a very rapid expansion of global market in satellite communication into personal communication and new mobile satellite services, such as Personal Communication System (PCS) and Mobile satellite Services (MSS) respectively, Low Earth Orbit (LEO) satellite systems, Global Positioning System (GPS) navigation, and new direct broadcast satellite services. LEO satellite services were introduced towards the end of 1990’s, and the growth depended on the competitive factors. The conventional Fixed Satellite services (FSS) and Maritime Mobile Satellite Services (MMSS) grew steadily but not as before.

Optical fiber cables, now forming a greater part of this communication revolution through out the world, severely challenged the fixed satellite services. Very high data rates, similar to High Dynamic Range (HDR) graphics, which requires greater than 155Mb per second of data transfer, which required excellent signal conditioning, were being carried by the fiber optics cables. Fiber optic cables have a better performance than satellites, having much less time delay in transmission. It was a time when satellite services needed to prove its advantage on HDR applications and networking, having a more modest data rates, for example T1=1.5Mb per second. A T-1 line actually consists of 24 individual channels, each of which supports up-to 64Kbits per second data rate. The advantages include, wide area coverage, distance insensitivity, flexibility, multiple access and destination capabilities and economy. Although much of the HDR traffic, such as multi-channel telephone trunks, from satellites to cables, will be transmitted through fiber optics cables, new opportunities opened up for HDR satellites to carry HDTV picture signal distribution, and also support the emerging field of Distributed High Performance Computing (DHPC). To gain access to this application market, HDR satellites needed to be developed and deployed commercially.

It was clear by now that the world of satellite communication was changing fast and threats existed for fixed satellite services, while new opportunities opened up in mobile, broadcast and personal services. Presently, the US leadership in satellite communication is being challenged, while it was undoubtedly the leader of such technology and was an agent of the changes in the past.

There are reasons as to why there has been a bleak assessment of the future of US in satellite communication technology. The important reasons include, the governments reduced role, lagging R&D effort, lack of systems conceptualisation, non-focusing of effort in new applications, and lack of effective industrial liaison and co-operation. On record, the assessment shows that during 1970’s and 1980’s there was extremely limited activity in US in the area of satellite communications projects, while there were frequent diverse research programs that were going on in Europe and Japan. Although these projects are of a different technology and much less budgeted than the US ones, the overall impression of US losing ground in the area of satellite communication is essentially correct.

The setting up of policy, planning, and supporting industrial development in different countries varies widely, with the governments of each country playing a key role in such activities. The policies and planning of the governments in Europe and Japan are far more aggressive than that of US, with the resources for such development being far more deployed. In-fact, in the last ten years, NASA has spent much less in satellite communication than its counterparts, the Japanese National Space Development Agency (NASDA) or the European Space Agency (ESA), although NASA’s total budget is many times greater.

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