Method and system for providing broadband mobile access from geostationary satellites to platforms using small, low profile antennas
First Claim
1. A satellite-based communications network, comprising a plurality of mobile user terminals with integrated tracking antennas;
- a communications satellite comprising at least a pair of transponders having overlapping frequency ranges and operative to transmit a downlink signal having certain polarization components and comprising video and audio content for reception by the mobile user terminals operating within a coverage area of the communications satellite;
a plurality of remote monitoring terminals positioned at locations within the coverage area of the communications satellite, each monitoring terminal operative to monitor the polarization components of the downlink signal as received by the monitoring terminal and to output measured polarization data in response to monitoring of the downlink signal; and
an uplink transmitting facility for transmitting an uplink signal for reception by the transponders of the communications satellite, the uplink transmitting facility responsive to the measured polarization data output by the monitoring terminals to control the relative phase and amplitude of the uplink signal, whereby the transponders are responsive to the relative phase and amplitude of the uplink signal to maintain at least a predetermined threshold of quality in the polarization components for the downlink signal received by the mobile user terminals operating in at least a portion of the coverage area for the communications satellite.
2 Assignments
0 Petitions
Accused Products
Abstract
A satellite-based communications system operating at high data rates in a broadcasting (multicasting) mode enables the use of mobile ground terminals with low profile antennas whose areas are significantly smaller than previous embodiments not using this invention. The invention can be applied to existing (in-orbit) or new satellites (including those in non-geostationary orbits) operating with linearly polarized downlink transponders. Important embodiments include the use of Ku FSS satellites providing service within the continental U.S. (“CONUS”), and the use of Ku BSS satellites operating within Europe. Transponder pairs on board the satellite with opposite linear polarization, but overlapping frequency bands, receive a specially processed uplink waveform from an uplink facility. Service may be optimized for (1) a particular geographical area by using receiving sensors located in that area, monitoring the polarization of the broadcast signal; or (2) a particular location with the satellite operating in a unicasting mode (delivery of Internet data or “local” video/audio broadcasts). A spread-spectrum waveform can also be used on the downlink, with the resultant processing gain applying directly to antenna area reduction and improved interference. Redundancy or increased capacity can be achieved by locating a second satellite in the same orbital location broadcasting the orthogonal circular (as received on the ground) polarization.
-
Citations
15 Claims
-
1. A satellite-based communications network, comprising
a plurality of mobile user terminals with integrated tracking antennas; -
a communications satellite comprising at least a pair of transponders having overlapping frequency ranges and operative to transmit a downlink signal having certain polarization components and comprising video and audio content for reception by the mobile user terminals operating within a coverage area of the communications satellite;
a plurality of remote monitoring terminals positioned at locations within the coverage area of the communications satellite, each monitoring terminal operative to monitor the polarization components of the downlink signal as received by the monitoring terminal and to output measured polarization data in response to monitoring of the downlink signal; and
an uplink transmitting facility for transmitting an uplink signal for reception by the transponders of the communications satellite, the uplink transmitting facility responsive to the measured polarization data output by the monitoring terminals to control the relative phase and amplitude of the uplink signal, whereby the transponders are responsive to the relative phase and amplitude of the uplink signal to maintain at least a predetermined threshold of quality in the polarization components for the downlink signal received by the mobile user terminals operating in at least a portion of the coverage area for the communications satellite. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. A satellite-based communications network, comprising
a plurality of mobile user terminals with integrated tracking antennas; -
a communications satellite comprising at least a pair of transponders having overlapping frequency ranges and operative to communicate a downlink signal having certain polarization components and comprising Internet data for reception by the mobile user terminals operating within a coverage area of the communications satellite;
a plurality of remote monitoring terminals positioned within the coverage area of the communications satellite, each monitoring terminal operative to monitor the polarization components of the downlink signal and to output measured polarization data in response to monitoring of the downlink signal;
a plurality of remote monitoring terminals positioned at locations within the coverage area of the communications satellite, each monitoring terminal operative to monitor the polarization components of the downlink signal as received by the monitoring terminal and to output measured polarization data in response to monitoring of the downlink signal; and
an uplink transmitting facility for transmitting an uplink signal for reception by the transponders of the communications satellite, the uplink transmitting facility responsive to the measured polarization data output by the monitoring terminals to adjust at least one correction factor for the uplink signal, whereby the transponders are responsive each correction factor of the uplink signal to maintain at least a predetermined threshold of quality in the polarization components of the downlink signal received by the mobile user terminals operating in at least a portion of the coverage area for the communications satellite. - View Dependent Claims (9, 10, 11, 12, 13)
-
-
14. A method for communicating a downlink signal via a communications satellite to a plurality of mobile user terminals operating within at least a portion of the coverage area for the communications satellite, the downlink signal having certain polarization parameters and comprising broadcast content, comprising the steps:
-
generating measured polarization data by measuring the polarization parameters of the downlink signal in response to monitoring the downlink signal at one or more ground locations within the coverage area of the communications satellite;
outputting the measured polarization data;
transmitting uplink signals for reception by the communications satellite, the uplink signals comprising adjustment factors for adjusting at least one of the polarization parameters of the downlink signal; and
varying at least one of the adjustment factors for the uplink signals in response to receipt of the measured polarization data to maintain at least a predetermined threshold of quality for the polarization parameters of the downlink signal as received at ground level by the mobile user terminals.
-
-
15. A method for communicating a downlink signal output via a communications satellite to a plurality of mobile user terminals operating within at least a portion of the coverage area for the communications satellite, the downlink signal having certain polarization parameters and comprising broadcast content, comprising the steps:
-
transmitting uplink signals for reception by the communications satellite, the uplink signals comprising adjustment factors for adjusting the polarization parameters of the downlink signal; and
varying at least one of the adjustment factors for the uplink signals based on measured polarization data to maintain at least a predetermined threshold of quality for the polarization parameters of the downlink signal as received at ground level by the mobile user terminals, the measured polarization data comprising measurements of the polarization parameters of the downlink signal, the measurements collected at one or more ground locations within the coverage area of the communications satellite.
-
Specification