Efficient high latitude service area satellite mobile broadcasting systems

• US 6,223,019 B1
• Filed: 05/20/1998
• Issued: 04/24/2001
• Est. Priority Date: 03/14/1996
• Status: Expired due to Term

• Current Assignee: Sirius XM Radio Inc. (Liberty Media Corporation)
• Original Assignee: Sirius Satellite Radio (Liberty Media Corporation)
• Inventors: Nelson, Robert A., Briskman, Robert D.
• Primary Examiner(s): Urban, Edward F.
• Application Number:
  US09/082,489
• Time in Patent Office: 1,070 Days
• Field of Search: 455/12.1, 455/13.1, 455/13.2, 455/507, 370/314, 370/317, 370/319, 244/158.R, 244/164
• US Class Current: 455/12.1
• CPC Class Codes: H04B 7/18523 Satellite systems for providing broadcast service to terrestrial stations, i.e. broadcast satellite service arrangements specially adapted for satellite broadcast receiving H04H40/90; picture transmission via satellite H04N1/00103; television transmission via satellite H04N7/20
• CPC Class Codes: H04B 7/195 Non-synchronous stations
• CPC Class Codes: H04H 40/90 specially adapted for satellite broadcast receiving

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.

Claims

1. A method of providing audio satellite broadcast transmissions to fixed and mobile receivers in a defined geographical service area that is, at least in part, in a latitude above about 30°

N or in a latitude below about 30°

S comprising providing a constellation of satellites, with each satellite in its own orbital plane, each orbital plane having orbital parameters that provide elevation angles of more than 35°

in said defined geographical service area, each satellite with a period of revolution around the earth substantially the same as the period of rotation of the earth on its axis;

transmitting, from two or more of said satellites, audio broadcast signals that are substantially identical in content;

transmitting at least two radio broadcast signals having frequencies in the range of about 1 to about 4 GHz from at least two satellites in said constellation substantially simultaneously, said radio broadcast signals having substantially the same content, to a plurality of mobile receivers for said signals in said area and at or near the earth'"'"'s surface, including the steps of;

broadcasting a first radio broadcast signal to said plurality of mobile receivers;

after a time delay of sufficient length to substantially eliminate outages in said area, said delay being at least about 0.5 seconds, following the broadcast of said first radio broadcast signal, broadcasting a second radio broadcast signal containing substantially the same program content as said first radio broadcast to said plurality of mobile receivers;

storing, in each of said mobile receivers, said first radio broadcast signal for a time period substantially the same as the time of said time delay; and

outputting from each of said plurality of mobile receivers, the program contents of first and said second radio broadcast signals by combining said first and said second radio broadcast signals for output or by selecting for output, in correct time-order progression, portions of said first radio broadcast signal and portions of said second radio broadcast signal.

2. The satellite audio broadcasting system of claim 1 wherein the satellites in said constellation are in orbital planes separated from one another by a number of degrees equal to 360°

divided by the number of satellites in said constellation.

3. The satellite broadcasting system of claim 1 wherein said orbital parameters for at least one satellite in said constellation minimize passage of said satellites through the Van Allen radiation belts around the earth.

4. The satellite audio broadcasting system of claim 1 wherein said orbital parameters minimize onboard satellite propulsion required to maintain each satellite in said constellation in its desired orbit.

5. The satellite audio broadcasting system of claim 1 wherein said orbital parameters are selected from the group consisting of satellite antenna pointing angles, satellite pattern rotation angles and satellite antenna beam shapes.

6. The satellite audio broadcasting system of claim 1 wherein said orbital parameters are selected from the group consisting of the inclination of each satellite, the eccentricity of the orbit for each satellite, the argument of perigee for each satellite in said constellation, the longitude of the ascending node of each orbit for each satellite in said constellation, and the ground trace for each satellite in said constellation.