HELICOPTER EMULATION OF ARCHIMEDES/MEDIASTAR SATELLITE DAB TRANSMISSION TO MOBILE RECEIVERS

Abstract

In the framework of the Archimedes programme, the European Space Agency (ESA) has been studying the application of satellites in multi-regional highly inclined elliptical orbits (M-HEO) for digital radio and related multimedia services and for mobile communications. More recently, these studies led to a proposal for an operational satellite-based EUREKA-147 Digital Audio Broadcasting (DAB) system. ESA studies have shown that an optimized satellite constellation of six HEO satellites in 8-h orbits could provide uninterrupted broadcast services in Europe, North America and East Asia with elevation angles significantly higher than those obtained with geostationary (GEO) satellites. The high elevation angles result in considerably less signal shadowing and multipath effects particularly in the case of mobile reception. Detailed channel characterization studies and performance analyses have demonstrated the feasibility of a digital audio broadcasting satellite system based on the European EUREKA-147 DAB standard. However, a number of uncertainties remained concerning the characteristics of the transmission channel and the EUREKA-147 DAB performance under operational conditions. ESA therefore awarded a contract to the German Aerospace Research Establishment (DLR) supported by the Institut fur Rundfunktechnik (IRT), to perform a so-called Archimedes DAB Measurement and Verification Campaign. The main objective of this campaign was the assessment of the EUREKA-147 DAB performance using a commercial receiver under a wide range of representative, ‘quasi-operational’ conditions by appropriately selected objective and subjective measures. Because no HEO satellite was available for these measurements, a helicopter emulating as closely as possible the characteristics of a HEO satellite was employed. The main results of the Archimedes DAB Measurement and Verification Campaign are reported in this study. These results are not specific only to the Archimedes system. © 1997 by John Wiley & Sons, Ltd.