US5444449A
Expired / Lapsed
US
⏱️ 0.0 years remaining
System and method for reducing interference between satellites
Assignee: Inmarsat Global Ltd
•
Filing: 1993-12-15
•
Granted: 1995-08-22
•
Expires: 2013-12-15
Abstract
Abstract A satellite system facilitates communications between earth stations and both geostationary satellites and non-geostationary satellites in an orbit at a lower altitude than that of said the geostationary satellites by preventing the non-geostationary satellite from transmitting signals that might possibly interfere with signals transmitted by the geostationary satellites. The non-geostationary satellite includes position acquisition subsystem for determining the position, and in particular the latitude, of the non-geostationary satellite relative to the surface of the earth. A data processor determines a forbidden band of locations on the surface of the earth all possible geostationary satellites and the non-geostationary satellite, at its determined position, are separated by less than a specified minimum discrimination angle. An antenna control subsystem in the non-geostationary satellite controls transmission of signal energy from the non-geostationary satellite in accordance with the satellites position so as to prevent transmission of signal energy from the non-geostationary satellite to said locations within the forbidden band.
Inventors
- 👤 Peter Poskett
- 👤 Dennis Mullins
- 👤 Shimichi Nomoto
- 👤 Stephane Gosselin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 23:04
CPC Classifications
H; H04; H04B; H04B7/00; H04B7/14; H04B7/15; H04B7/185; H04B7/1851; H04B7/18513; H04B7/204; H04B7/2041
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
181 words
A method of operation of a satellite system having a geostationary orbital band occupied by at least one geostationary satellite and a non-geostationary satellite in an orbit at a lower altitude than that of said at least one geostationary satellite, comprising the steps of: determining position of said non-geostationary satellite relative to the surface of the earth; calculating a minimum discrimination angle between said geostationary band and non-geostationary satellite at its determined position relative to a ground station on earth, wherein said minimum discrimination angle corresponds to a predefined threshold of interference between signals received by said ground station from said non-geostationary satellite and geostationary satellites in said geostationary orbital band; defining a forbidden band of locations on the surface of the earth from which said geostationary orbital band and said non-geostationary satellite, at its determined position, are separated by less than said minimum discrimination angle; and controlling transmission of signal energy from said non-geostationary satellite in accordance with said position thereof so as to prevent transmission of signal energy from said non-geostationary satellite to said locations within said forbidden band.
Claim 2
Independent Claim
181 words
A method of operation of a satellite system having a geostationary orbital band occupied by at least one geostationary satellite and a non-geostationary satellite in an orbit at a lower altitude than that of said at least one geostationary satellite, comprising the steps of: determining position of said non-geostationary satellite relative to the surface of the earth; calculating a minimum discrimination angle between said geostationary band and non-geostationary satellite at its determined position relative to a ground station on earth, wherein said minimum discrimination angle corresponds to a predefined threshold of interference between signals received by said ground station from said non-geostationary satellite and geostationary satellites in said geostationary orbital band; defining a forbidden band of locations on the surface of the earth from which said geostationary orbital band and said non-geostationary satellite, at its determined position, are separated by less than said minimum discrimination angle; and controlling transmission of signal energy from said non-geostationary satellite in accordance with said position thereof so as to prevent transmission of signal energy from said non-geostationary satellite to said locations within said forbidden band.
Claim 3
Dependent Claim
42 words
The method of operation of claim 1 wherein said step of controlling transmission further includes the step of adjusting an antenna beam pattern projected by said non-geostationary satellite such that energy therefrom is not incident upon said locations within said forbidden band.
Claim 4
Dependent Claim
40 words
The method of operation of claim 2 wherein said step of adjusting said antenna beam pattern further includes the step of projecting spot beams only to regions on the surface of the earth outside of said forbidden band of locations.
Claim 5
Dependent Claim
63 words
The method of operation of claim 1 wherein said step of defining a forbidden band of locations on the surface of the earth includes the step of specifying a forbidden band of latitude range on the surface of the earth from within which selected orbital positions proximate said geostationary orbit are separated from said non-geostationary satellite by less than said minimum discrimination angle.
Claim 6
Dependent Claim
35 words
The method of operation of claim 1 wherein said step of controlling transmission includes the step of preventing transmission of signals from said non-geostationary satellite within a field of view thereof encompassing said forbidden band.
Claim 7
Dependent Claim
47 words
The method of operation of claim 1 wherein said step of defining a forbidden band of locations on the surface of the earth includes the step of storing forbidden bands of locations corresponding to selected positions of said non-geostationary satellite in a memory on said non-geostationary satellite.
Claim 8
Dependent Claim
53 words
The method of operation of claim 6 wherein said step of controlling transmission of signal energy from said non-geostationary satellite includes the step of preventing transmission of signal energy from said non-geostationary satellite to said forbidden bands of locations stored in said memory in accordance with said determined position of said non-geostationary satellite.
Claim 9
Dependent Claim
149 words
A satellite system having a geostationary orbital band occupied by at least one geostationary satellite and a non-geostationary satellite in an orbit at a lower altitude than that of said at least one geostationary satellite, said non-geostationary satellite including an antenna control subsystem comprising: position acquisition means for determining position of said non-geostationary satellite relative to the surface of the earth; a data processor, coupled to said position acquisition means, that defines a forbidden band of locations on the surface of the earth from which said geostationary orbital band and said non-geostationary satellite, at its determined position, are separated by less than a specified minimum discrimination angle; and means, coupled to said data processor, for controlling transmission of signal energy from said non-geostationary satellite in accordance with said position thereof so as to prevent transmission of signal energy from said non-geostationary satellite to said locations within said forbidden band.
Claim 10
Dependent Claim
149 words
A satellite system having a geostationary orbital band occupied by at least one geostationary satellite and a non-geostationary satellite in an orbit at a lower altitude than that of said at least one geostationary satellite, said non-geostationary satellite including an antenna control subsystem comprising: position acquisition means for determining position of said non-geostationary satellite relative to the surface of the earth; a data processor, coupled to said position acquisition means, that defines a forbidden band of locations on the surface of the earth from which said geostationary orbital band and said non-geostationary satellite, at its determined position, are separated by less than a specified minimum discrimination angle; and means, coupled to said data processor, for controlling transmission of signal energy from said non-geostationary satellite in accordance with said position thereof so as to prevent transmission of signal energy from said non-geostationary satellite to said locations within said forbidden band.
Claim 11
Dependent Claim
39 words
The system of claim 8 wherein said means for controlling transmission further includes means for adjusting an antenna beam pattern projected by said second satellite such that energy therefrom is not incident upon said locations within said forbidden band.
Claim 12
Dependent Claim
37 words
The system of claim 9 wherein said means for adjusting said antenna beam pattern further includes means for projecting spot beams only to regions on the surface of the earth outside of said forbidden band of locations.
Claim 13
Dependent Claim
48 words
The system of claim 8 wherein said data processor includes means for specifying a forbidden band of latitude range on the surface of the earth from within which selected orbital positions proximate said geostationary orbit are separated from said second satellite by less than said minimum discrimination angle.
Claim 14
Dependent Claim
32 words
The system of claim 8 wherein said means for controlling transmission includes means for preventing transmission of signals from said second satellite within a field of view thereof encompassing said forbidden band.
Claim 15
Dependent Claim
34 words
The system of claim 8 wherein said data processor further includes a memory that stores forbidden bands of locations corresponding to selected positions of said non-geostationary satellite in a memory on said non-geostationary satellite.
Claim 16
Dependent Claim
50 words
The system of claim 13 wherein said means for controlling transmission of signal energy from said non-geostationary satellite includes means for preventing transmission of signal energy from said non-geostationary satellite to said forbidden bands of locations stored in said memory in accordance with said determined position of said non-geostationary satellite.
Claim 17
Independent Claim
156 words
A method of operation of a satellite system having a geostationary orbital band occupied by at least one geostationary satellite and a non-geostationary satellite in an orbit at a lower altitude than that of said at least one geostationary satellite, comprising the steps of: determining position of said non-geostationary satellite relative to the surface of the earth; defining a forbidden band of locations on the surface of the earth from which said geostationary orbital band and said non-geostationary satellite, at its determined position, are separated by less than a specified minimum discrimination angle corresponding to a predefined threshold of interference at the surface of the earth between signals from said non-geostationary satellite and said geostationary satellites in said geostationary orbital band; and controlling transmission of signal energy from said non-geostationary satellite in accordance with said position thereof so as to prevent transmission of signal energy from said non-geostationary satellite to said locations within said forbidden band.
Claim 18
Independent Claim
156 words
A method of operation of a satellite system having a geostationary orbital band occupied by at least one geostationary satellite and a non-geostationary satellite in an orbit at a lower altitude than that of said at least one geostationary satellite, comprising the steps of: determining position of said non-geostationary satellite relative to the surface of the earth; defining a forbidden band of locations on the surface of the earth from which said geostationary orbital band and said non-geostationary satellite, at its determined position, are separated by less than a specified minimum discrimination angle corresponding to a predefined threshold of interference at the surface of the earth between signals from said non-geostationary satellite and said geostationary satellites in said geostationary orbital band; and controlling transmission of signal energy from said non-geostationary satellite in accordance with said position thereof so as to prevent transmission of signal energy from said non-geostationary satellite to said locations within said forbidden band.
Claim 19
Dependent Claim
42 words
The method of operation of claim 15 wherein said step of controlling transmission further includes the step of adjusting an antenna beam pattern projected by said non-geostationary satellite such that energy therefrom is not incident upon said locations within said forbidden band.
Claim 20
Dependent Claim
40 words
The method of operation of claim 16 wherein said step of adjusting said antenna beam pattern further includes the step of projecting spot beams only to regions on the surface of the earth outside of said forbidden band of locations.
Claim 21
Dependent Claim
47 words
The method of operation of claim 15 wherein said step of defining a forbidden band of locations on the surface of the earth includes the step of storing forbidden bands of locations corresponding to selected positions of said non-geostationary satellite in a memory on said non-geostationary satellite.
Claim 22
Dependent Claim
53 words
The method of operation of claim 18 wherein said step of controlling transmission of signal energy from said non-geostationary satellite includes the step of preventing transmission of signal energy from said non-geostationary satellite to said forbidden bands of locations stored in said memory in accordance with said determined position of said non-geostationary satellite.
References Cited (Backward Citations)
US4315262A
Cited
US5227802A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-08-21 | 1999-02-20 | 1999-08-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-08-21 | 2003-02-20 | 2003-08-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-08-21 | 2007-02-20 | 2007-08-22 | $7700.00 | Window Closed / Lapsed |