Abstract: An apparatus comprises a plurality of antenna elements, a plurality of digital signal processing devices for supplying phase-and-amplitude-weighted digital baseband signals, a beamforming processor for processing the weighted digital baseband signals to adaptively form a plurality of beam patterns for the antenna elements, a plurality of digital modulators for converting the digital baseband signals into intermediate frequency digital signals, and a modulator for modulating in-phase and quadrature components of the intermediate frequency digital signals to produce composite radio frequency output signals for the antenna elements. Receiving apparatus, and methods of transmitting and receiving a plurality of signals on a plurality of antenna elements are also provided.

Abstract: An apparatus comprises a distributed array of antenna elements for receiving a radio frequency signal on a satellite communications link, wherein the radio frequency signal includes a known preamble; a plurality of mixers for translating the radio frequency signal to a plurality of baseband signals having in-phase and quadrature components; a processor for applying weights to the baseband signals, wherein the weights are found adaptively in response to the preamble in combination with decision-directed feedback when the preamble is not present; and a receiver for processing the weighted baseband signals. A pre-processor can be used to create sub-arrays of the antenna elements using maximal-ratio weighting. A method performed by the apparatus is also provided.

Abstract: An apparatus comprises a first sensor mounted on a first platform for sampling a first portion of a continuous waveform occurring in a time window and for producing a first signal sample, a second sensor mounted on a second platform for sampling a second portion of the continuous waveform occurring in the time window for producing a second signal sample, and a processor for determining time difference of arrival measurements and for applying a maximum likelihood estimation process to combine multiple time difference of arrival measurements between multiple pairs of platforms, to estimate the location of an emitter of the continuous waveform. A method performed by the apparatus is also provided.

Abstract: An apparatus comprises a first sensor mounted on a first platform for sampling a first portion of a continuous waveform occurring in a time window and for producing a first signal sample, a second sensor mounted on a second platform for sampling a second portion of the continuous waveform occurring in the time window for producing a second signal sample, and a processor for determining time difference of arrival measurements and for applying a maximum likelihood estimation process to combine multiple time difference of arrival measurements between multiple pairs of platforms, to estimate the location of an emitter of the continuous waveform. A method performed by the apparatus is also provided.

Abstract: An apparatus comprises a distributed array of antenna elements for receiving a radio frequency signal on a satellite communications link, wherein the radio frequency signal includes a known preamble; a plurality of mixers for translating the radio frequency signal to a plurality of baseband signals having in-phase and quadrature components; a processor for applying weights to the baseband signals, wherein the weights are found adaptively in response to the preamble in combination with decision-directed feedback when the preamble is not present; and a receiver for processing the weighted baseband signals. A pre-processor can be used to create sub-arrays of the antenna elements using maximal-ratio weighting. A method performed by the apparatus is also provided.