Dynamic mapping apparatus for mobile unit acquisition and method therefor
First Claim
1. In a communication system having a gateway and non-geostationary satellite nodes, each providing a plurality of antenna beams that move with respect to earth'"'"'s surface, a method of identifying one of said antenna beams in which a subscriber unit is located comprising the steps of:
- (a) determining a geographic location of said subscriber unit by said gateway, said geographic location being in earth-based coordinates;
(b) identifying a satellite node having a footprint region presently servicing said geographic location, said footprint region being defined by ground projections of said plurality of antenna beams provided by said satellite node;
(b1) sending said earth-based coordinates to said satellite node;
(b2) converting, at said satellite node, said earth-based coordinates to satellite-based coordinates, said satellite-based coordinates being relative to said identified satellite node;
(c) mapping said satellite-based coordinates to a first antenna beam provided by said satellite node; and
(d) transmitting an acquisition signal to said subscriber unit in said first antenna beam.
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Accused Products
Abstract
A called subscriber unit'"'"'s geographic location is provided by a gateway and translated to location coordinates of a global coordinate system. The gateway identifies an orbiting satellite communication station servicing the subscriber unit'"'"'s location, and sends the subscriber unit'"'"'s ID and location data to the satellite. The subscriber unit'"'"'s location data is translated to an angle and range relative to the satellite'"'"'s nadir using the satellite'"'"'s ground track data. The angle and range are mapped to an antenna beam where the subscriber unit is located using a look-up table onboard the satellite. An acquisition or ring-alert signal is transmitted within the antenna beam where the subscriber unit is located. When the range is outside the satellite'"'"'s footprint, the subscriber unit'"'"'s ID and location data are routed directly to another satellite currently servicing that location.
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Citations
22 Claims
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1. In a communication system having a gateway and non-geostationary satellite nodes, each providing a plurality of antenna beams that move with respect to earth'"'"'s surface, a method of identifying one of said antenna beams in which a subscriber unit is located comprising the steps of:
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(a) determining a geographic location of said subscriber unit by said gateway, said geographic location being in earth-based coordinates; (b) identifying a satellite node having a footprint region presently servicing said geographic location, said footprint region being defined by ground projections of said plurality of antenna beams provided by said satellite node; (b1) sending said earth-based coordinates to said satellite node; (b2) converting, at said satellite node, said earth-based coordinates to satellite-based coordinates, said satellite-based coordinates being relative to said identified satellite node; (c) mapping said satellite-based coordinates to a first antenna beam provided by said satellite node; and (d) transmitting an acquisition signal to said subscriber unit in said first antenna beam. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A communication system comprising:
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a communication node that provides a plurality of antenna beams, said communication being in non-geostationary orbit, said communication node having a footprint region defined by ground projections of said antenna beams; and a gateway that comprises; means for determining a geographic location of a subscriber unit, said geographic location being in earth-based coordinates; and means for sending said earth-based coordinates to said communication node, said communication node having been identified as having said footprint region servicing said geographic location, and said communication node includes means for converting said earth-based coordinates to satellite-based coordinates, said satellite-based coordinates being relevant to said communication node means for mapping said earth-based coordinates to a first antenna beam of said plurality of antenna beams provided by said satellite node; and means for transmitting an acquisition signal to said subscriber unit in said first antenna beam. - View Dependent Claims (16, 17, 18, 19, 20)
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21. A method of dynamically mapping location information between coordinate systems comprising the steps of:
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determining a geographic location of a subscriber unit in a first coordinate system, said geographic location defined by a first and second angle relative to a vector through earth'"'"'s center; translating said first and second angle to a second coordinate system to arrive at a third angle and a range, said third angle and said range being relative to a nadir vector of an orbiting communication station, wherein said orbiting communication station has a footprint region servicing said geographic location; identifying an antenna beam within said footprint region based on said third angle and range; and transmitting a signal within said antenna beam from said orbiting communication station to said subscriber unit. - View Dependent Claims (22)
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Specification