Space Systems/loral, LLC

David Grybos

Farid Elwailly

James Knecht

William Hreha

Beamforming channels of a satellite are calibrated using a low power, spread spectrum calibration signal. The power of the calibration signal is below the noise level of a user signal in an active channel, allowing channels to be calibrated while active. When calibrating the transmit side circuitry, a two-stage calibration can be used, first calibrating the output hybrid matrix, then calibrating the whole of the transmit side. To improve performance, the dwell time spend calibrating a channel can be based on the power of the user signal in the channel. A transmit probe can be used to inject a calibration signal into the receive antennae and a receive probe can be used to extract the calibration signal from the transmit antennae. To reduce frequency of calibrations, the calibrations can be based on path-to-path differences. These techniques are also applied to multiport amplifiers (MPAs).

Multiport amplifier input network with compensation for output network gain and phase frequency response imbalance

Beamforming channels of a satellite are calibrated using a low power, spread spectrum calibration signal. The power of the calibration signal is below the noise level of a user signal in an active channel, allowing channels to be calibrated while active. When calibrating the transmit side circuitry, a two-stage calibration can be used, first calibrating the output hybrid matrix, then calibrating the whole of the transmit side. To improve performance, the dwell time spend calibrating a channel can be based on the power of the user signal in the channel. A transmit probe can be used to inject a calibration signal into the receive antennae and a receive probe can be used to extract the calibration signal from the transmit antennae. To reduce frequency of calibrations, the calibrations can be based on path-to-path differences.

Calibration of satellite beamforming channels

A communication platform such as a spacecraft, airborne platform, or terrestrial line of site wireless platform is provided with adaptive digital beamforming. The satellite digitizes a full spectrum allocation for digital channelization. A channelization engine can determine a particular user or user group associated with an uplink signal. In this manner, the communication platform can apply different processing based on the user or group associated with a signal. For example, the communication platform receives uplink signals associated with a first user group and a second user group in one embodiment. The platform dynamically generates one or more spot beams for the first user group and the second group. The platform discriminates the uplink signals to apply frequency hopping for the downlink frequency channel assignments to the second user group while the downlink frequency channel assignments for the first user group remain fixed.

Protected overlay of assigned frequency channels

Disclosed herein is a system including analog receive paths and analog transmit paths and signal processing equipment onboard a satellite, and methods for use therewith. For each of a plurality of the analog receive paths, a calibration signal is injected therein below a noise floor thereof, while the path is actively used to receive and condition an RF signal, and the calibration signal is extracted from the analog receive path after the signal has traveled through at least a portion of the path. The extracted calibration signal is compared to the injected calibration signal to determine gain and phase deviations caused by the path. Gain and phase characteristics of the analog receive paths are adjusted to compensate for different gain and phase deviations being caused by different paths. Similar techniques are used to compensate for different gain and phase deviations being caused by different analog transmit paths.

Satellite system calibration in active operational channels

Communications apparatus, such as a multibeam satellite communications system on-board a satellite, or terrestrial communications system, and methods that use a data routing technique that is based on the assignment of one or more codes corresponding to a destination beam. In particular, data routing is performed based on a CDMA code. The communications apparatus and methods allow simplified processing of the data address and routing of the data.

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San Jose, CA, United States of America

David Grybos