Satellite system using optical gateways and ground based beamforming
First Claim
1. A ground based subsystem for use in transmitting an optical feeder uplink beam to a satellite that includes a multiple element antenna feed array and that is configured to receive the optical feeder uplink beam and in dependence thereon use the multiple element antenna feed array to produce and transmit a plurality of RF service downlink beams to service terminals, the ground based subsystem comprising:
- a ground based beamformer (GBBF) configured to accept a plurality of spot beam signals, produce or otherwise obtain phase and amplitude beamforming coefficients, and output a plurality of feed element signals in dependence on the plurality of spot beam signals and the phase and amplitude beamforming coefficients;
a plurality of lasers, each of the lasers operable to emit an optical signal having a different peak wavelength within a specified optical wavelength range;
a plurality of electro-optical modulators (EOMs), each EOM of the plurality of EOMs configured to accept an optical carrier signal from a respective one of the plurality of lasers, accept a different one of the plurality of feed element signals from the GBBF, and output a respective optical feed element signal in dependence on the optical carrier signal and the feed element signal accepted by the EOM;
a wavelength-division multiplexing (WDM) multiplexer configured to accept the optical feed element signals output by the plurality of EOMs, and combine the plurality of optical feed element signals into a wavelength division multiplexed optical signal;
an optical amplifier configured to amplify the wavelength division multiplexed optical signal to thereby produce an optically amplified wavelength division multiplexed optical signal; and
transmitter optics configured to accept the optically amplified wavelength division multiplexed optical signal and transmit an optical feeder uplink beam to the satellite in dependence thereon.
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Accused Products
Abstract
Described herein are ground based subsystems, and related methods, for use in transmitting an optical feeder uplink beam to a satellite that includes a multiple element antenna feed array and that is configured to accept the optical feeder uplink beam and in dependence thereon use the multiple element antenna feed array to produce and transmit a plurality of radio frequency (RF) service downlink beams to service terminals. Certain embodiments are related to a ground based beamformer (GBBF) for inclusion in a ground based subsystem, and methods for use therewith. Beneficially, embodiments described herein allow for flexible antenna beam forming for large signal bandwidth without the limitation associated with the available gateway uplink and downlink spectrum at RF frequencies. Also described herein are space based subsystems for use with such ground based subsystems.
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Citations
23 Claims
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1. A ground based subsystem for use in transmitting an optical feeder uplink beam to a satellite that includes a multiple element antenna feed array and that is configured to receive the optical feeder uplink beam and in dependence thereon use the multiple element antenna feed array to produce and transmit a plurality of RF service downlink beams to service terminals, the ground based subsystem comprising:
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a ground based beamformer (GBBF) configured to accept a plurality of spot beam signals, produce or otherwise obtain phase and amplitude beamforming coefficients, and output a plurality of feed element signals in dependence on the plurality of spot beam signals and the phase and amplitude beamforming coefficients; a plurality of lasers, each of the lasers operable to emit an optical signal having a different peak wavelength within a specified optical wavelength range; a plurality of electro-optical modulators (EOMs), each EOM of the plurality of EOMs configured to accept an optical carrier signal from a respective one of the plurality of lasers, accept a different one of the plurality of feed element signals from the GBBF, and output a respective optical feed element signal in dependence on the optical carrier signal and the feed element signal accepted by the EOM; a wavelength-division multiplexing (WDM) multiplexer configured to accept the optical feed element signals output by the plurality of EOMs, and combine the plurality of optical feed element signals into a wavelength division multiplexed optical signal; an optical amplifier configured to amplify the wavelength division multiplexed optical signal to thereby produce an optically amplified wavelength division multiplexed optical signal; and transmitter optics configured to accept the optically amplified wavelength division multiplexed optical signal and transmit an optical feeder uplink beam to the satellite in dependence thereon. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for enabling a ground based subsystem to produce and transmit an optical feeder uplink beam to a satellite that includes a multiple element antenna feed array and that is configured to receive the optical feeder uplink beam and in dependence thereon use the multiple element antenna feed array to produce and transmit a plurality of RF service downlink beams to service terminals, the method for use by the ground based subsystem comprising:
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performing ground based beamforming by accepting a plurality of spot beam signals, producing or otherwise obtaining phase and amplitude beamforming coefficients, and producing a plurality of feed element signals in dependence on the plurality of spot beam signals and the phase and amplitude beamforming coefficients; emitting a plurality of optical carrier signals each having a different peak wavelength that is within a specified optical wavelength range; electro-optically modulating each of the optical carrier signals with one of feed element signals produced by the ground based beamforming to thereby produce a plurality of optical feed element signals; multiplexing the plurality of optical feed element signals to thereby produce a wavelength division multiplexed optical signal that includes data for the plurality of RF service downlink beams; producing an optical feeder uplink beam, in dependence on the wavelength division multiplexed optical signal; and transmitting the optical feeder uplink beam through free-space to the satellite. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A ground based subsystem for use in transmitting an optical feeder uplink beam to a satellite that includes a multiple element antenna feed array and that is configured to receive the optical feeder uplink beam and in dependence thereon use the multiple element antenna feed array to produce and transmit a plurality of RF service downlink beams to service terminals, the ground based subsystem comprising:
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a ground based beamformer (GBBF) including a GBBF controller, a signal replication and forward beamforming weighting unit that is controlled by the GBBF controller, and a plurality of summers; the GBBF controller configured to produce phase and amplitude beamforming coefficients in dependence on calibration information accepted from a calibration subsystem; the signal replication and forward beamforming weighting unit configured to replicate each of a plurality of spot beam signals, weight each of the replicated spot beam signals in dependence on phase and amplitude beamforming coefficients produced by the GBBF controller, and output a set of phase and amplitude weighted signals; the plurality of summers configured to sum respective subsets of the phase and amplitude weighted signals to thereby produce a plurality of feed element signals; a plurality of lasers, each of the lasers operable to emit an optical signal having a different peak wavelength within a specified optical wavelength range; a plurality of electro-optical modulators (EOMs), each EOM of the plurality of EOMs configured to accept an optical carrier signal from a respective one of the plurality of lasers, accept a different one of the plurality of feed element signals from the GBBF, and output a respective optical feed element signal in dependence on the optical carrier signal and the feed element signal accepted by the EOM; a wavelength-division multiplexing (WDM) multiplexer configured to accept the optical feed element signals output by the plurality of EOMs, and combine the plurality of optical feed element signals into a wavelength division multiplexed optical signal; an optical amplifier configured to amplify the wavelength division multiplexed optical signal to thereby produce an optically amplified wavelength division multiplexed optical signal; and transmitter optics configured to accept the optically amplified wavelength division multiplexed optical signal and transmit an optical feeder uplink beam to the satellite in dependence thereon. - View Dependent Claims (19, 20, 21, 22, 23)
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Specification