Patent ID: 7548187

Claim:
In an aircraft-mounted active radar for detecting incoming threats, a method for adaptively setting the clutter line of a filter used to reject clutter to correspond to the Doppler shift associated with sensed aircraft ground speed, comprising the steps of: analog-to-digitally converting radar pulses received at the aircraft from a surveilled area; range gating the returned pulses; multiplying a predetermined number of pulses from a range gate with weights; applying the pulse weights to a fast Fourier transform to generate side-by-side Doppler cells; and, selecting those Doppler cells for activation having Doppler shift frequencies above a clutter line Doppler shift frequency associated with the sensed aircraft ground speed, thereby to reject clutter having Doppler shifts below the aircraft ground speed and for passing returns having Doppler shift frequencies above the aircraft ground speed, whereby the clutter rejection line is set in accordance with the sensed aircraft ground speed.