Abstract: An off-line processor arrangement for a broadband accelerated convergence adaptive antenna array wherein signals from a plurality of antenna elements are applied to respective identical tapped delay lines (T) the outputs of which are fed through individual signal weighting means to a beamforming network (BFN), the arrangement including one or more lattice filter means (LF) to which the auxiliary antenna element signals are applied together with the output response of the beamforming network to compute sets of weight correction vectors (* W) with which to update weight coefficients and means for storing said updated coefficients, said stored coefficients being applied to the individual signal weighting means to weight the outputs of the tapped delay lines.

Abstract: A data processing system for a phased array antenna consisting of an array of transmit/receive elements which result in a significant reduction in the data processing requirements for the received signals. In operation, the RF transmitted and received beams are formed and steered in a conventional manner with a phase shifter and amplitude weighting for each element. However, a simplifying approximation is made in the signal processing of the received signals for interference suppression, which results in minimal degradation of the system performance. In such a system, interference suppression is obtained by generating nulls in the receive antenna pattern in the direction of the interference. The nulls are produced by adjusting the phase and amplitude (weight) of the received signal from each array element just enough to null the interference with minimal impact on the rest of the antenna pattern.

Abstract: An adaptive array processor is disclosed for processing the signals from a main antenna and one or more auxiliary antennas to provide suppression of wideband interference. The outputs from the respective antennas are transformed into the frequency domain by synchronized chirp transformers conducted over a transform block length. The transformed auxiliary antenna signal is weighted by time varying, frequency dependent weights which are adaptively determined. The transformed main antenna and weighted auxiliary antenna signals are then combined. The combined signal is then transformed back to the frequency domain by an inverse chirp transformation.

Abstract: The effects of multipath and other interference signals in communication receivers are reduced by implementing an adaptive array. The invention addresses a signal environment in which the directions of arrival and the time of arrival of the signal of interest and the unwanted multipath or interference signals are unknown. The feedback equation of the LMS adaptive array is changed so that a reference signal is not needed. The system uses the strongest received signal as the signal of interest and rejects the other received signals.

Abstract: A null processing receiver apparatus that receives and combines together a number of modulated information signals in such a fashion that an interference or jamming signal superimposed on each received signal is substantially eliminated from the combined signal. The apparatus first demodulates each received signal to baseband, to produce a primary demodulated signal and one or more auxiliary demodulated signals. The apparatus then appropriately weights the one or more auxiliary signals and sums together the weighted signals with the primary signal to produce a sum signal in which the interference is substantially nulled out. The weighting is based on a cross-correlation of the sum signal with the baseband signals themselves.

Abstract: An adaptive antenna comprising at least two sensors for receiving electromagnetic signals and for producing first signals; the antenna further including divider means for dividing each first signal into respective second and third signals; weighting means for modifying each respective second signal according to a quantized weighting function; summing means for summing the respective second signals to provide a fourth signal; means for producing a system feedback signal in response to the fourth signal; limiter means for limiting the dynamic range of the system feedback signal; correlator means for correlating the respective third signals with the limited system feedback signal to produce respective correlator output signals; means for determining the signal environment power level of the far field sensed by the at least two sensors and for providing a fifth signal substantially corresponding to 1/.sqroot.

Abstract: An adaptive power equalizer circuit for use in a spread spectrum receiver system which includes an antenna system 12, 13 and a receiver 11, the circuit comprising adaptive power inversion circuitry 15 for producing a first signal having a minimized power level and a second signal having a substantially higher power level than that of the first signal. Such signals are supplied to a power equalizer circuitry 16 which equalizes the power levels thereof, such equalized power level signals then being combined in a suitable combiner circuit 30 for producing an output receiver output signal for the receiver 11.

Abstract: Disclosed is an antenna system having a first antenna directed to receive a desired signal wave and a second antenna directed to receive only an interference signal wave superposed on the desired signal wave. Both signals received by the first and second antennas are combined and the amplitude and phase shift necessary for the second antenna signal to cancel the interference signal component existing in the first antenna signal is calculated from the combined signal. By combining the controlled second antenna signal with the first antenna signal, the desired reception signal having an improved S/N ratio can be obtained.

Abstract: An adaptive antenna 10 embodying the present invention includes an array of sensors 12. Each sensor 12 has associated therewith a main channel 14, a feedthrough path 16 and a feedback path 18. Correlators 20 coprocess signals in the feedthrough path 16 and the feedback path 18; the result is transformed according to an algorithm by a computer 22 which controls a weighting circuit 24. The weighting circuit 24 thus progressively modifies the signal in the main channel 14 to minimize interference with a desired signal. Placement of a limiter 26 along the feedback path 18 simplifies correlator design relative to adaptive antennas without such limiters and improves performance relative to adaptive antennas with limiters in the feedthrough path.