Abstract: Satellite audio broadcasting systems include orbital constellations for providing high elevation angle coverage of audio broadcast signals from the constellation's satellites to fixed and mobile receivers within service areas located at geographical latitudes well removed from the equator.

Abstract: A satellite audio broadcasting system for mobile and fixed receivers at or near the earth's surface in geographic service areas at latitudes above about 30 degrees N or below about 30 degrees S include a satellite constellation of two or more satellites, each in its own geosynchronous orbit, with each orbit having orbital parameters that provide elevation angles of more than 35 degrees throughout the service area.

Abstract: A broadcast receiving system for use with an FM radio transmitter in a vehicle includes an adapter unit and an antenna unit. The adapter unit includes a connector to a vehicle's existing power system, e.g., cigarette lighter receptacle. The adapter unit receives audio program signals from the antenna unit, and retransmits them to a vacant FM channel or to an intermediate frequency channel of the vehicle's FM radio receiver. The antenna unit receives radio broadcast signals having frequencies in the range of about 300 MHZ to about 4000 MHz from satellites and terrestrial repeaters.

Abstract: A digital radio broadcasting system using spread spectrum modulation transmitted from both geosynchronous satellites and terrestrial repeater stations provides multi-program audio services to mobile and fixed user receivers over a large geographical area in an ubiquitous manner.

Abstract: A radio receiver augmentation system for insertion in a cassette player or compact disc player includes a receiver unit and an antenna unit. The receiver unit includes an insertable element having a size and shape suitable for insertion in a tape cassette receiving slot of a cassette player/radio combination or in a compact disc receiving slot of a compact disc player/radio combination and delivers audio program signals to the magnetic head of the tape cassette player or the optical coupler of the compact disc player. The audio program signals come by retransmission from an antenna unit that receives radio broadcast signals from satellites and their terrestrial repeaters having frequencies in the range of about 300 MHZ to about 4000 MHZ. The system's circuitry conditions the signal for aural presentation through the tape cassette player/radio combination or compact disc player/radio combination.

Abstract: Mobile radio receivers in a broadcasting system having more than one transmission channel sending the same programs use time diversity to prevent service outages during periods when none of the channels can be received.

Abstract: The methods and systems for reducing multipath fading and outage from blockage in a radio broadcasting system that is adapted to simultaneously broadcast signals having frequencies in the range of about 300 MHz to about 3,000 MHz from two or more satellite sources traveling on a substantially geosynchronous orbit with the satellite sources separated from one another by a sufficient distance to minimize outage from physical blockages and multipath fading of signals from these satellites and received by a plurality of fixed and mobile platforms using substantially flat, hemispherical coverage antennas, each antenna having an outer diameter no greater than about 10 inches and each adapted to receive frequencies in the range of about 300 MHz to about 3,000 MHz.

Abstract: High quality audio broadcasts at radio frequencies to mobile receivers at or near the earth's surface are provided by substantially simultaneous transmission of the same signal from two geosynchronous, spatially-separated satellites on the geosynchronous orbit which virtually eliminates multipath fading and foliage attenuation and thereby permits the use of a low-cost space segment.

Abstract: High quality audio broadcasts at radio frequencies to mobile receivers at or near the earth's surface are provided by substantially simultaneous transmission of the same signal from two geosynchronous, spatially-separated satellites on the geosynchronous orbit which virtually eliminates multipath fading and foliage attenuation and thereby permits the use of a low-cost space segment.

Abstract: Automatic frequency control is provided in a satellite-based spread spectrum radio communication system by employing a pilot signal as a frequency reference. A transmitter inserts the pilot signal at a null point in the power versus frequency spectrum of the transmitted spread spectrum signal in order to minimize bandwidth requirements and to avoid interference between the pilot signal and the transmitted data.