Mobile satellite systems: A review

Abstract

The advantages of a mobile satellite system have been recognized worldwide, and after the 1979 World Administrative Radio Conference (WARC) identified spectrum in the 806 to 890 MHz band for region 2, the Canadian Government quickly took steps to provide mobile satellite services for all of Canada including the 200 mile offshore ocean territorial limits. A comprehensive set of technical, economic, and policy studies have been completed in Canada to determine the viability of a mobile service to satisfy Canada's requirements. This paper will present an overall review of these studies, give a rationale as to why narrowband technologies are necessary for the commercial viability of this service, and the approach taken in the development of these technologies. A brief review of activities and proposed mobile satellite systems in other areas besides North America is also given. The effect of an early entry by commercial interests (Telesat in Canada) will be examined including system parameters which require careful coordination within Canada and the U.S. operations in order to assure commercial viability in both countries. A review of some common requirements in the Canadian and U.S. systems will be discussed in order to standardize the system and equipment approaches for each country and provide mutual back-up in the event of a spacecraft anomaly. The trade-offs between the use of UHF (800 MHz) and L-Band (1.5 GHz) when used for true mobile applications are discussed. A hybrid system design is explored which would make the most appropriate use of both bands.