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

• US 20090004967A1
• Filed: 07/11/2007
• Published: 01/01/2009
• 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 7,917,080 B2
• Time in Patent Office: Days
• US Class Current: 455/13.100
• 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

1-20. -20. (canceled)

21. A reception apparatus, comprising:

a terrestrial receive antenna for receiving a first signal from a terrestrial transmitter on a frequency usable by at least one satellite transmitting to a satellite receive antenna having a sensitivity characterizable by a satellite receive antenna primary sensitive axis directed substantially at the satellite, the terrestrial receive antenna having a terrestrial receive antenna primary sensitive axis directed substantially toward the Equator.

22. The apparatus of claim 21, 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.

23. The apparatus of claim 21, 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.

24. The apparatus of claim 21, wherein the satellite receive antenna is further characterizable by at least one posterior secondary sensitive axis.

25. The apparatus of claim 21, wherein the satellite is disposed in a substantially geosynchronous orbit.

26. The apparatus of claim 21, wherein the satellite is disposed in a substantially geostationary orbit.

27-72. -72. (canceled)

73. An apparatus capable of substantially simultaneous reception of a first signal from a non-terrestrial source and a second signal from a terrestrial source, comprising:

a first antenna, having a primary sensitive axis directed substantially at the non-terrestrial source and at least one secondary sensitive axis directed away from the primary sensitive axis by a first angle greater than 90 degrees; and

a second antenna having a sensitive axis directed away from the primary sensitive axis by a second angle less than 90 degrees.

74. The apparatus of claim 73, wherein second angle is between approximately 10 degrees and 90 degrees.

75. The apparatus of claim 73, wherein the second angle is approximately 10 degrees.

76. The apparatus of claim 73, wherein the second angle comprises a second angle azimuth component and a second angle elevation angle component, and wherein the second angle azimuth component is between approximately −

90 and 90 degrees and the second angle elevation component is between approximately 10 and 90-δ

degrees, wherein δ

describes and angle from due South to a vector from the satellite receive antenna to the satellite.

77. The apparatus of claim 73, wherein the first angle is between approximately 96 and 132 degrees.

78. An apparatus for substantially simultaneously receiving a first signal from a non-terrestrial source and a second signal from a terrestrial source, comprising:

a first antenna having polar sensitivity characteristic having a plurality of lobes and nulls disposed therebetween, wherein one of the lobes is a main lobe disposed substantially along a primary sensitive axis and at least one of the remaining lobes is a side lobe disposed substantially along a secondary sensitive axis wherein a first angle defined by the primary sensitive axis and the secondary sensitive axis is greater than 90 degrees; and

a second antenna having a sensitive axis directed away from the secondary node and away from the primary node.

79. The apparatus of claim 78, wherein the second antenna sensitive axis is directed away from the primary sensitive axis by an angle less than 90 degrees.

80. An apparatus for simultaneously receiving a first signal transmitted from a non-terrestrial source and a second signal from a terrestrial source, comprising:

a first antenna having a sensitivity characteristic having a plurality of lobes and nulls disposed therebetween;

a second antenna having a sensitivity characteristic having at least one lobe; and

wherein at least one of the first antenna nodes is directed substantially at the non-terrestrial source and at least one of the first antenna nulls is directed substantially at the terrestrial source and at least one of the second antenna nodes is directed substantially at the terrestrial source.

81. The apparatus of claim 80, wherein the second antenna comprises a plurality of lobes having nulls therebetween and wherein at least one of the nulls is directed substantially at the non-terrestrial source.

82. The apparatus of claim 80, wherein the plurality of first antenna lobes includes main lobe directed substantially at the non-terrestrial source and a secondary lobe disposed at a polar angle greater than 90 degrees from the main lobe.

83. An apparatus for simultaneously receiving a first signal transmitted from a non-terrestrial source and a second signal from a terrestrial source, comprising:

a first antenna having a sensitivity characteristic including

a main lobe defining a primary sensitive axis directed substantially at the non-terrestrial source;

at least one side lobe defining a secondary sensitive axis;

at least one null between the main lobe and the side lobe defining an insensitive axis directed substantially at the terrestrial source; and

a second antenna having a sensitive axis directed substantially at the terrestrial source.

84. The apparatus of claim 83, wherein the secondary sensitive axis is disposed at an angle greater than 90 degrees from the primary sensitive axis.

85. The apparatus of claim 83, wherein the first antenna comprises two sensitive secondary axes disposed at an angle greater than 90 degrees from the primary sensitive axis.

86. The apparatus of claim 85, wherein the secondary sensitive axes are disposed at an angle approximately 114 degrees from the primary sensitive axis.

87. A transmission network for transmitting a first signal and a second signal simultaneously to a location, comprising:

a first antenna, having a sensitivity characterizable by a plurality of lobes and nulls disposed therebetween, wherein the plurality of nodes comprises a main lobe and at least one side lobe;

a second antenna, having a sensitivity characterizable by a main lobe;

a non-terrestrial transmitter, disposed at a location relative to the first antenna to transmit the first signal along a first axis substantially aligned with the main lobe; and

a terrestrial transmitter, disposed at a location relative to the first antenna to transmit the second signal along a second axis substantially aligned with a null and at an angle less then 90 degrees from the main lobe.

88. The transmission network of claim 87, wherein the side lobe is disposed at an angle greater than 90 degrees from the main lobe.

89. A method of aligning a receiver system comprising two antennas to receive a first signal from a non-terrestrial source and a second signal from a terrestrial source at a location on a single channel, comprising the steps of:

aligning an azimuth and elevation angle of a first antenna to direct a first antenna main lobe substantially at the non-terrestrial source; and

adjusting the azimuth and elevation angle of the first antenna to direct a first antenna null substantially at the terrestrial source and to direct a first antenna side lobe substantially away from the terrestrial source; and

wherein the first antenna main lobe and the first antenna null are separated by a polar angle less than 90 degrees; and

the first antenna main lobe and the first antenna side lobe are separated by a polar angle of greater than 90 degrees.

90. The method of claim 89, further comprising the step of:

aligning a second antenna to direct a second antenna main lobe at the terrestrial source.

91. A method of simultaneously receiving a first signal from a non-terrestrial source and a second signal from a terrestrial source at a location on a single channel, comprising the steps of:

receiving the first signal with the first antenna via a first antenna main lobe;

substantially rejecting the second signal with the first antenna via a first antenna null angularly displaced from the main lobe by less than 90 degrees; and

receiving a second signal with a second antenna.

92. The method of claim 91, further comprising the step of:

rejecting the first signal with the second antenna via a second antenna null.

93. The method of claim 91, wherein the first antenna further comprises at least one posterior first antenna side lobe.

94. An apparatus for simultaneously receiving a first signal from a non-terrestrial source and a second signal from a terrestrial source, comprising:

a first antenna having an anterior primary sensitive axis directed substantially at the non-terrestrial source and at least one posterior secondary sensitive axis; and

a second antenna having a sensitive axis directed to the terrestrial source and substantially aligned with an insensitive axis of the first antenna.

95. The apparatus of claim 94, wherein the second antenna is disposed proximate the first antenna.