Northrop Grumman Systems Corporation

Trw Limited

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Stephen Deane Stearns

A method and apparatus for processing cochannel signals received at a sensor array in a cumulant-based signal processing and separation engine to obtain a desired set of output signals or parameters. For use in a signal recovery system, the output signals are recovered and separated versions of the originally transmitted cochannel signals. An important feature that distinguishes the cumulant-based system from other signal separation and recovery systems is that it generates an estimated generalized steering vector associated with each signal source, and representative of all received coherent signal components attributable to the source. This feature enables the invention to perform well in multipath conditions, by combining all coherent multipath components from the same source. In a receiver/transmitter system, the estimated generalized steering vectors associated with each source are used to generate transmit beamformer weight vectors that permit cochannel transmission to multiple user stations. The basic cumulant-based processing and separation engine can also be used in a variety of applications, such as high density recording, complex phase angle equalization, receiving systems with enhanced effective dynamic range, and signal separation in the presence of strong interference. Various embodiments and extensions of the basic cumulant-based system are disclosed.

Method for extending the effective dynamic range of a radio receiver system

A method for processing received radio signals that are subject to unwanted change during propagation through the atmosphere, from a transmitter to a receiver array. The multiple signals are received as cochannel signals at the antenna array, and are processed to eliminate the effects of modification of the signals during propagation, wherein the processing step includes cumulant-based signal recovery without regard for the geometrical properties of the antenna array. In the invention as disclosed, two different information signals having two different polarization states are transmitted, and at least one of the transmitted signals is subjected to an unwanted change of its polarization state. The received signals are processed to separate and recover the two information signals without regard to their polarization states.

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Sunnyvale, CA, United States of America

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