Phase coherent interference signal suppression system and method

DETAILED DESCRIPTION The present invention is an interference signal suppression system which comprises a first and second receiving antenna positioned to receive a communication signal and which are physically spaced one from the other.
Phase and amplitude altering means are coupled to one of the antennas for altering the phase and amplitude of the signal received at that antenna by an amount corresponding to the phase and amplitude difference between the signals at the two antennas resulting from the physical spacing thereof.
Means are provided for inverting the signal received at one of the antennas.
The signal from the phase and amplitude altering means and the signal received at the other antenna are summed.
This results in the coherent signals being nulled one by the other.
The non-coherent signals do not null and can therefore be captured by known methods for demodulating non-coherent radio frequency signals.
In a specific embodiment of the invention, the first and second receiving antennas will be spaced between forty and fifty wavelengths from each other to ensure that the tropospheric reflected scattered signal exhibits the required noncoherence at the two antenna locations.
It is therefore an object of the invention to provide a system for suppressing phase coherent interference signals in a reflected scattered signal communication system.
It is another object of the invention to provide such a system which is capable of distinguishing between a reflected scattered wave signal and a coherent jamming signal.
Still another object of the invention is to provide such a system which utilizes a pair of physically displaced antennas and which includes means for nullinq the coherent jamming signals received at the antennas.
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