Method and apparatus for mitigating interference from terrestrial broadcasts sharing the same channel with satellite broadcasts using an antenna with posterior sidelobes

• US 20040235418A1
• Filed: 06/21/2004
• Published: 11/25/2004
• Est. Priority Date: 12/03/1999
• Status: Active Grant

• Current Assignee: The DIRECTV Group, Inc. (AT&T, Inc.)
• Original Assignee: The DIRECTV Group, Inc. (AT&T, Inc.)
• Inventors: Anderson, Paul R.
• Granted Patent: US 7,257,370 B2
• Time in Patent Office: Days
• US Class Current: 455/11.1
• CPC Class Codes: H01Q 1/52 Means for reducing coupling between antennas; Means for reducing coupling between an antenna and another structure absorbing means H01Q17/00
• CPC Class Codes: H01Q 3/2605 Array of radiating elements provided with a feedback control over the element weights, e.g. adaptive arrays
• CPC Class Codes: H04B 7/18513 Transmission in a satellite or space-based system

Abstract

An apparatus for simultaneously receiving a first signal from a non-terrestrial source and a second signal from a terrestrial source on the same or overlapping channels using a receive antenna with posteriorly-directed sidelobes is disclosed. The apparatus comprises at least one terrestrial transmitter transmitting information on at least one frequency simultaneously usable by at least one satellite transmitting to a satellite receive antenna having a sensitivity characterizable by a primary sensitive axis directed substantially at satellite. The terrestrial transmitter includes a azimuthal gain characteristic directed substantially away from the Earth'"'"'s Equator. In an alternative embodiment, the terrestrial transmitter is disposed at a location defining a vector angularly displaced from the primary sensitive axis by an angle of less than 90 degrees. A method of transmitting information is also disclosed. In this method the information is transmitted on at least one frequency simultaneously usable by at least one satellite transmitting to a satellite receive antenna having a sensitivity characterizable by a primary sensitive axis directed substantially at the satellite and a posterior secondary sensitive axis. The method is performed by transmitting the information from a terrestrially-based transmitter to a terrestrial receive antenna in a direction substantially away from the Equator.

Claims

1. A terrestrially-based transmission system, comprising:

at least one terrestrial transmitter transmitting information on at least one frequency simultaneously usable by at least one geosynchronous satellite transmitting to a satellite receive antenna having a sensitivity characterizable by a primary sensitive axis directed substantially at the satellite; and

wherein the terrestrial transmitter has an azimuthal gain characteristic directed substantially away from the Equator.

2. The system of claim 1, wherein the transmitter is characterizable by an azimuthal gain characteristic substantially limited to an angle φ

defined by AZ_TW and AZ_TE, the angle φ

determined according to a latitude of the satellite receive antenna and a minimum elevation angle of the primary sensitive axis ε

_min.

3. The system of claim 1, wherein the terrestrial transmitter has an azimuthal gain characteristic substantially limited to between AZ_TW and AZ_TE, wherein AZ_TW is about 295°

Northwest and AZ_TE is about 65°

Northeast.

4. The system of claim 1, wherein the terrestrial transmitter has an azimuthal gain characteristic substantially limited to between AZ_TW and AZ_TE, wherein AZ_TW is about 245°

Southwest and AZ_TE is about 115°

Southeast.

5. The system of claim 1, wherein the satellite receive antenna is further characterizable by at least one posterior secondary sensitive axis.

11. The system of claim 1, wherein the transmitter is characterizable by an azimuthal gain characteristic substantially limited to an angle φ

defined by AZ_TW and AZ_TE, the angle φ

determined according to a latitude of the satellite receive antenna and a minimum elevation angle of the primary sensitive axis ε

_min.

6. A method of transmitting information on at least one frequency simultaneously usable by at least one geosynchronous satellite transmitting to a satellite receive antenna having a sensitivity characterizable by a primary sensitive axis directed substantially at the satellite and a posterior secondary sensitive axis, comprising the step of:

transmitting the information from a terrestrially-based transmitter to a terrestrial receive antenna in a direction substantially away from the Equator.

7. The method of claim 6, wherein the transmitter is characterizable by an azimuthal gain characteristic substantially limited to an angle φ

defined by AZ_TW and AZ_TE, the angle φ

determined according to a lattitude of the satellite receive antenna and a minimum elevation angle of the primary sensitive axis ε

_min.

8. The method of claim 6, wherein the information is transmitted in a direction between AZ_TW and AZ_TE wherein AZ_TW is about 295°

Northwest and AZ_TE is about 65°

Northeast.

9. The method of claim 8, wherein the information is transmitted in a direction between AZ_TW and AZ_TE wherein AZ_TW is about 245°

Southwest and AZ_TE is about 115°

Southeast.

10. A method of receiving information transmitted on at least one frequency simultaneously usable by at least one geosynchronous satellite transmitting to a satellite receive antenna having a sensitivity characterizable by a primary sensitive axis directed substantially at the satellite and a posterior secondary sensitive axis, comprising the step of:

receiving the information with a terrestrial receive antenna from a terrestrially-based transmitter transmitting the information in a direction substantially away from the Equator.

12. The method of claim 10 wherein the information is transmitted in a direction between AZ_TW and AZ_TE wherein AZ_TW is about 295°

Northwest and AZ_TE is about 65°

Northeast.

13. The method of claim 10, wherein the information is transmitted in a direction between AZ_TW and AZ_TE wherein AZ_TW is about 245°

Southwest and AZ_TE is about 115°

Southeast.