Adaptive clutter cancellation for synthetic aperture AMTI radar

In combination with a multichannel AMTI synthetic aperture radar system in which each channel includes a receive antenna, a coherent receiver connected thereto and a synthetic aperture processing circuit connected to process the output of the coherent receiver, means for maintaining optimum clutter cancellation between two adjacent channels comprising

• a delay means connected between the forward channel coherent receiver and synthetic aperture processing circuit,
• a first complex multiplier having two inputs and an output, a first input thereof being connected to the aft channel coherent receiver and the output being connected to the aft channel synthetic aperture processing circuit,
• a first signal averaging means connected to the output of the forward channel synthetic aperture processing circuit,
• a second signal averaging means connected to the output of the aft channel synthetic aperture processing circuit,
• a signal complex conjugate transform means,
• a scalor constant means,
• second and third complex multipliers each having two inputs and an output,
• first, second and third summing means, each having two inputs and an output,
• a unit delay means, and an initial clutter cancellation signal source, the output of said first signal averaging means being connected to a first input of said third summing means, the output of said second signal averaging means being connected to said signal complex conjugate transform means and to a first input of said third complex multiplier, said second complex multiplier having its first input connected to the output of said signal complex conjugate transform means and its second input connected to the output of said third summing means, the output of said third complex multiplier being connected to the second input of said third summing means, said scalor constant means being connected between the output of said second complex multiplier and a first input of said first summing means, said unit delay means being connected between the output of said first summing means and a first input of said second summing means, said first input of said second summing means being connected to the second input of said first summing means, said second summing means having its second input connected to said initial clutter cancellation signal source and its output connected to the second input of said third complex multiplier and to the second input of said first complex multiplier.