A method and system facilitate communication between a constellation of satellites and a mobile platform-mounted mobile communicator. The method and system may include the use of a first antenna suited for operation using a first frequency band in a first geographic region and a second antenna suited for operation using either the first or a second frequency band in a second geographic region. The method and system may use a controller to determine which antenna to activate based on one or more of a geographic indicator or a signal indicator. The system used by the method to facilitate the communication may have one or more enclosures over the antennas and controller for mounting to a mobile platform.

A method and system facilitate communication between a constellation of satellites and a mobile platform-mounted mobile communicator. The method and system may include the use of a first antenna suited for operation using a first frequency band in a first geographic region and a second antenna suited for operation using either the first or a second frequency band in a second geographic region. The method and system may use a controller to determine which antenna to activate based on one or more of a geographic indicator or a signal indicator. The system used by the method to facilitate the communication may have one or more enclosures over the antennas and controller for mounting to a mobile platform.

A phased array antenna system has at least one trough reflector, each trough reflector having at least one phased array located at a feed point of the reflector, and an array of elements located near to a point equal to one half of a center transmission wavelength. A method of decoding a receive signal includes propagating a transmit signal through a transmit and a receive path of a phased array to generate a coupled signal, digitizing the coupled signal, storing the digitized coupled signal, receiving a signal from a target, and using the digitized coupled signal to decode the signal from the target. A method of modeling the ionosphere includes transmitting measuring pulses from an incoherent scattering radar transmitter, receiving incoherent scatter from the transmitting, and analyzing the incoherent scatter to determine pulse and amplitude of the incoherent scatter to profile electron number density of the ionosphere.

A phased array antenna system has at least one trough reflector, each trough reflector having at least one phased array located at a feed point of the reflector, and an array of elements located near to a point equal to one half of a center transmission wavelength. A method of decoding a receive signal includes propagating a transmit signal through a transmit and a receive path of a phased array to generate a coupled signal, digitizing the coupled signal, storing the digitized coupled signal, receiving a signal from a target, and using the digitized coupled signal to decode the signal from the target. A method of modeling the ionosphere includes transmitting measuring pulses from an incoherent scattering radar transmitter, receiving incoherent scatter from the transmitting, and analyzing the incoherent scatter to determine pulse and amplitude of the incoherent scatter to profile electron number density of the ionosphere.

A method of setting phases of a multitude of transmit elements of a phased array includes, in part, setting a phase of a first transmit element to N different values during each of N different time intervals, transmitting an electromagnetic signal from the first transmit element at each of the N time intervals, measuring a power of the electromagnetic signal at a receiving unit during each of the N time intervals, and selecting coefficients of a basis function such that a difference between a power value computed by the basis function and the measured power value associated with each of the N phases is smaller than a threshold value. The threshold value is optionally defined by a minimum of the sum of squares of the difference between a power value computed by the basis function and the power value for each of the N phases.

A method of setting phases of a multitude of transmit elements of a phased array includes, in part, setting a phase of a first transmit element to N different values during each of N different time intervals, transmitting an electromagnetic signal from the first transmit element at each of the N time intervals, measuring a power of the electromagnetic signal at a receiving unit during each of the N time intervals, and selecting coefficients of a basis function such that a difference between a power value computed by the basis function and the measured power value associated with each of the N phases is smaller than a threshold value. The threshold value is optionally defined by a minimum of the sum of squares of the difference between a power value computed by the basis function and the power value for each of the N phases.

Techniques are disclosed implementing two alternative approaches for adaptive beamforming for MIMO radar. The first of these includes a “reduced complexity” iterative adaptive approach (RC-IAA) algorithm, which uses two steps including a delay-and-sum beamforming step (DAS-BF) and an IAA step that is applied to the output generated by the DAS-BF step. A second technique is described that includes a “beam space” iterative adaptive approach (BS-IAA) algorithm, which uses three steps including a delay-and-sum beamforming step (DAS-BF), a region of interest (ROI) detection step that is applied to the output generated by the DAS-BF, and an IAA step that is applied to detected ROIs.

Techniques are disclosed implementing two alternative approaches for adaptive beamforming for MIMO radar. The first of these includes a “reduced complexity” iterative adaptive approach (RC-IAA) algorithm, which uses two steps including a delay-and-sum beamforming step (DAS-BF) and an IAA step that is applied to the output generated by the DAS-BF step. A second technique is described that includes a “beam space” iterative adaptive approach (BS-IAA) algorithm, which uses three steps including a delay-and-sum beamforming step (DAS-BF), a region of interest (ROI) detection step that is applied to the output generated by the DAS-BF, and an IAA step that is applied to detected ROIs.

Systems, methods, and computer-readable media are described for combining digital and analog beamsteering in a channelized antenna array. In some examples, a method can include receiving one or more signals at each of a plurality of groups of antenna elements, each group of antenna elements defining a respective channel from a plurality of channels, and steering, by each respective channel and using analog steering, the one or more signals in a respective direction to yield a steered analog signal pattern. The method can further include converting the steered analog signal pattern associated with each respective channel into a respective digital signal and, based on the respective digital signal, generating, using digital steering, digital signal patterns steered within the steered analog signal pattern associated with the respective digital signal.

Systems, methods, and computer-readable media are described for combining digital and analog beamsteering in a channelized antenna array. In some examples, a method can include receiving one or more signals at each of a plurality of groups of antenna elements, each group of antenna elements defining a respective channel from a plurality of channels, and steering, by each respective channel and using analog steering, the one or more signals in a respective direction to yield a steered analog signal pattern. The method can further include converting the steered analog signal pattern associated with each respective channel into a respective digital signal and, based on the respective digital signal, generating, using digital steering, digital signal patterns steered within the steered analog signal pattern associated with the respective digital signal.