Abstract: Acquisition and interpretation of reflections from a target in response to a Doppler radar probe signal from a seeker are inhibited by providing at the target a receiver, preferably a high-speed sweeping transceiver, which is operative to injection lock quickly to the probe signal and thereafter to repeat a low-power replica of the probe signal with frequency modulation of the carrier from the repeater with a deviation greater than the locking bandwidth of the local oscillator to generate a random aperiodic signal. The vehicle operator is notified of the presence of seeker signals to prompt the operator to verify compliance with vehicle operating regulations. The carrier frequency modulation is selected to be of a frequency and deviation sufficient to confuse phase locking and limiting circuitry in a seeker receiver and thereby to inhibit acquisition of an echo from the target.