Viasat, Inc.

The Aerospace Corporation

Peter S Wyckoff

Joseph J Luna

Philip A Dafesh

David Hancharik

Parker A Robinson

Methods, systems, and devices for satellite operations are described. A satellite communications system may include a transmitter that applies multiple spreading codes to a data signal to obtain multiple spread data signals. The transmitter may transmit the multiple spread data signals from multiple antenna elements in a composite signal. The satellite communications system may also include a receiver that receives the composite signal and applies multiple despreading codes to the composite signal to obtain multiple despread data signals. The receiver may combine the multiple despread data signals to obtain a combined data signal that corresponds to the data signal processed by the transmitter. To combine the multiple despread data signals, the receiver may estimate coefficients for each of the despread data signals.

Satellite communications using spread signals

A system for communications may include an antenna array, where an inter-element spacing of antennas of the antenna array may be different across the antenna array; antenna managers that are coupled with respective antennas and configured to transmit and receive ranging signals used to measure parameters representative of distances between a respective antenna and the other antennas; a calibration unit that determines positions of the antennas based on the measured parameters and positions of reference antennas; and a communications manager that communicates with a terminal according to beam coefficients determined for the antenna array based on the determined positions of the antennas.

Sparse antenna array calibration

Disclosed is an antenna array system including an antenna array of N≥2 antenna elements that output N antenna signals; an interferer-nulling beam forming network (IN-BFN) coupled to the antenna array, N non-linear filters coupled to the IN-BFN, and a desired signal BFN. The IN-BFN may include N 'null BFNs' to generate N null signals, each null BFN applying a respective nulling beam weight set to the N antenna signals to generate a respective one of the N null signals. Each respective nulling beam weight set corresponds to a different respective set of (N−1) independent nulls. Each of the N non-linear filters may filter a respective one of the N null signals to provide a respective one of N filtered signals. The desired signal BFN may apply a desired signal beam weight set to the N filtered signals to generate an output signal.

Antenna array system with disparate beam forming networks and non-linear filtering to mitigate interference

One example includes a phased-array antenna system (). The system includes antenna elements () each including an element adjustment circuit () and a radiating element (). A beamforming network () receives a carrier signal and generates element carrier signals. A baseband DSP () generates a plurality of composite beamforming data signals associated with a respective one of the antenna elements () and is generated based on combining individual beamforming data signals. Each of the individual beamforming data signals is associated with a respective beam and is based on combining a data signal associated with the respective beam with an antenna weight associated with the respective beam and the respective one of the antenna elements (). The element adjustment circuit () modulates the associated composite beamforming data signal onto the respective element carrier signal to generate a respective element signal that is provided to the respective radiating element (), such that the beams are generated from the antenna elements ().

Multi-beam antenna system with a baseband digital signal processor

Systems and methods are provided for processing a time-domain signal in rectangular coordinates. The signal can include a low power desired signal and a high power, approximately constant envelope interference signal that spectrally overlaps the desired signal. A rectangular to polar converter can obtain magnitude and phase of the time-domain signal in polar coordinates. An interference estimator can estimate a magnitude of the interference signal based on the magnitude of the time-domain signal in polar coordinates. A subtractor can obtain a difference magnitude in polar coordinates based on the magnitude of the time-domain signal and the estimated magnitude of the interference signal in polar coordinates. A polar to rectangular converter can obtain the desired signal with reduced power of the interference signal based on the difference magnitude and phase of the time-domain signal in polar coordinates.

Systems and methods for reducing a relatively high power, approximately constant envelope interference signal that spectrally overlaps a relatively low power desired signal

Systems and methods are provided for processing time-domain samples of a digitized signal in rectangular coordinates. The digitized signal can include a low power desired signal and a high power, approximately constant envelope interference signal that spectrally overlaps the desired signal. A rectangular to polar converter can obtain magnitude and phase of each time-domain sample in polar coordinates. An interference estimator can estimate a magnitude of the interference signal based on magnitudes of a predetermined number of time-domain samples in polar coordinates. A subtractor can obtain a difference magnitude for each time-domain sample in polar coordinates based on the magnitude of that sample and the estimated magnitude of the interference signal in polar coordinates. A polar to rectangular converter can obtain time-domain samples in rectangular coordinates of the desired signal with reduced power of the interference signal based on the difference magnitude and phase of time-domain samples in polar coordinates.

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Scottsdale, AZ, United States of America

Peter S Wyckoff