Aircraft radar system with feedback of range signal to antenna elevation control anddisplay of equirange contours

Claim 1

APPARATUS FOR DISPLAYING TO THE PILOT OF AN AIRCRAFT A TWO-DIMENSIONAL REPRESENTATION OF THE TERRAIN TOWARD AND OVER WHICH SAID AIRCRAFT IS FLYING WHICH COMPRISES MEANS FOR PROJECTING AN ENERGY BEAM TOWARD A POINT OF SAID TERRAIN, MEANS FOR RECOVERING REFLECTED ENERGY RETURNED FROM SAID POINT, MEANS FOR DERIVING FROM SAID REFLECTED ENERGY A CONTROL SIGNAL REPRESENTATIVE OF THE PROPAGATION TIME OF SAID ENERGY OVER ITS PROJECTED AND REFLECTED PATHS, MEANS FOR ANGULARLY SWEEPING SAID BEAM ACROSS SAID TERRAIN IN AN AZIMUTH COORDINATE, MEANS RESPONSIVE TO SAID CONTROL SIGNAL FOR ANGULARLY DEFLECTING SAID BEAM IN AN ELEVATION COORDINATE TO HOLD CONSTANT SAID PROPAGATION TIME AT EACH OF A SET OF DISCRETELY DIFFERENT VALUES, ONE FOR EACH OF SAID AZIMUTHAL SWEEPS, A DISPLAY SCREEN, AN INDICATOR, AND MEANS CAUSING SAID INDICATOR TO MOVE ON SAID SCREEN IN HORIZONTAL AND VERTICAL DIRECTIONS