Continuous wave radar with ppi type display

Claim 1

A PLAN POSITION INDICATING SYSTEM TO INDICATE THE RELATIVE POSITIONS OF OBJECTS BELOW A MOVING CRAFT COMPRISING AZIMUTH SWEEPING RADAR MEANS TRANSMITTING A CONTINUOUS WAVE SIGNAL AND RECEIVING ITS REFLECTION FROM SAID OBJECTS, SWEEP POSITION DETECTION MEANS COUPLED TO THE ANTENNA SWEEP DRIVE OF SAID RADAR MEANS, PLAN POSITION INDICATING MEANS COUPLED TO THE OUTPUT OF SAID SWEEP POSITION DETECTION MEANS, A PLURALITY OF FILTER MEANS TO SEPARATE EACH OF A PLURALITY OF DOPPLER SHIFTED FREQUENCY SIGNALS IN THE RECEIVED SIGNAL FROM SAID RADAR MEANS, PULSE GENERATING MEANS, MEANS COUPLING THE OUTPUT OF SAID PULSE GENERATING MEANS WITH SAID SWEEP POSITION DETECTION MEANS TO TRIGGER THE SWEEP OF A GIVEN SECTOR IN ADVANCE OF AND BELOW SAID MOVING CRAFT, A PLURALITY OF DELAY MEANS COUPLING THE OUTPUT OF SAID PULSE GENERATING MEANS TO SAID FILTER MEANS TO SEPARATE DOPPLER SHIFTED FREQUENCY SIGNALS EACH OF SAID DELAY MEANS REPRESENTING A GIVEN RADIAL DISTANCE ON SAID PLAN POSITION INDICATING MEANS, SO THAT A COINCIDENCE OF SIGNALS PASSED BY SAID FILTER MEANS AND PULSES FROM SAID PULSE GENERATING MEANS CAUSES PULSES TO BE FED TO SAID PLAN POSITION INDICATING MEANS TO INDICATE THE RELATIVE POSITIONS OF SAID OBJECTS.