Narrowband beamformer using nonlinear oscillators

A narrowband beamformer for operation on the output of a sensor array having a plurality of sensors, the sensor array being beamsteered in the direction of a mainbeam signal, each sensor for receiving the mainbeam signal of approximate frequency, Ω, and sidelobe signals of approximate frequency, Ω, said narrowband beamformer comprising:

• a plurality of nonlinear oscillators, one said nonlinear oscillator connected to each sensor, each said nonlinear oscillator coupled to at least one other said nonlinear oscillator to allow each said nonlinear oscillator to create an output having a frequency of approximately, Ω, in response to receipt of the mainbeam signal by the sensor array and to simultaneously allow each said nonlinear oscillator to create an output in a frequency spectrum that is centered on a frequency of approximately, {overscore (ω)}, in response to receipt of a sidelobe signal by the sensor array;
• a summer connected to each said nonlinear oscillator for receiving and summing said nonlinear oscillator outputs and creating a summer output;
• and
• a matched filter connected to said summer for receiving said summer output and separating said summer output by frequency to distinguish the mainbeam signal from the sidelobe signals.

A method for beamforming the output of a plurality of beamsteered sensors comprising the steps of:

• setting a critical phase lag, ΔφC;
• providing a plurality of nonlinear oscillators;
• connecting a separate said nonlinear oscillator to each beamsteered sensor;
• coupling each said nonlinear oscillator to at least one other said nonlinear oscillator;
• connecting each said nonlinear oscillator to a summer;
• and
• adjusting the coupling strength between said coupled oscillators to cause said summer to output a signal having an approximate frequency, Ω, in response to receipt of a signal having an approximate frequency, Ω, by said beamsteered sensors when the phase lag, Δφ, between any two beamsteered sensors is less than said critical phase lag, Δφc, and to output a spectrum of signals centered on an approximate frequency, {overscore (ω)}, in response to receipt of a signal of frequency, Ω, by said beamsteered sensors when the phase lag, Δφ, between any two beamsteered sensors is greater than said critical phase lag, Δφc.