Terrain avoidance radar system

Claim 1

A TERRAIN AVOIDANCE RADAR SYSTEM FOR AN AIRBORNE VEHICLE COMPRISING MEANS FOR SENDING RADAR SIGNALS INTO A PREDETERMINED REGION IN FRONT OF SAID AIRBORNE VEHICLE TO DETECT THE PRESENCE OF AN OBSTACLE IN SAID PREDETERMINED REGION, AT LEAST A PORTION OF SAID PREDETERMINED REGION COMPRISING A SCAN PROFILE, A PORTION OF THE BOUNDARY OF SAID SCAN PROFILE LYING AT A DISTANCE FROM SAID AIRBORNE VEHICLE WHICH VARIES IN ACCORDANCE WITH ITS ANGULAR POSITION WITH RESPECT TO SAID AIRBORNE VEHICLE, RECEIVER MEANS FOR RECEIVING THE RETURN RADAR SIGNALS, FLIGHT CONTROL LOGIC MEANS CONNECTED TO SAID RECEIVER MEANS AND EFFECTIVE RESPONSIVE TO THE RECEIPT OF REFLECTED RADAR SIGNALS FOR PRODUCING FLIGHT CONTROL COMMAND SIGNALS TO CONTROL THE FLIGHT PATH OF SAID AIRBORNE VEHICLE TO AVOID DETECTED OBSTACLES, A BISTABLE DEVICE FOR CONTROLLING THE GENERATION OF SAID FLIGHT CONTROL COMMAND SIGNALS IN SAID FLIGHT CONTROL LOGIC MEANS, MEANS FOR APPLYING A TRIGGER PULSE TO SAID BISTABLE DEVICE TO PLACE SAID BISTABLE DEVICE IN A FIRST STABLE STATE WHEN A RADAR PULSE IS EMITTED INTO SAID PREDETERMINED REGION, VARIABLE TIME DELAY MEANS FOR APLYING TIMING SIGNALS TO SAID BISTABLE DEVICE, SAID TIMING SIGNALS BEING CHANGED IN ACCORDANCE WITH SAID VARIATION OF SAID PORTION OF THE BOUNDARY FOR SAID SCAN PROFILE TO MAINTAIN SAID BISTABLE DEVICE IN SAID FIRST STABLE STATE AS LONG AS THE AREA WITHIN SAID SCAN PROFILE IS BEING INVESTIGATED, THE DURATION OF THE TIME SAID BISTABLE DEVICE IS MAINTAINED IN SAID FIRST STABLE STATE BEING CHANGED AT A FIRST RATE DURING A FIRST INTERVAL OF TIME, SAID DURATION BEING CHANGED AT A SECOND RATE DURING A SECOND INTERVAL OF TIME, AND SAID DURATION REMAINING CONSTANT DURING A THIRD INTERVAL OF TIME, SAID VARIABLE TIME DELAY MEANS INCLUDING MEANS FOR PRODUCING A FIRST PULSE AT A PREDETERMINED TIME AFTER SAID TRIGGER PULSE, SAID PREDETERMINED TIME VARYING AT SAID FIRST RATE, MEANS FOR PRODUCING A SECOND PULSE AT A PRESELECTED TIME AFTER SAID TRIGGER PULSE, SAID PRESELECTED TIME VARYING AT SAID SECOND RATE, MEANS FOR PRODUCING A THIRD PULSE AT A CONSTANT TIME AFTER SAID TRIGGER PULSE, SAID FIRST PULSE OCCURRING FIRST IN TIME DURING SAID FIRST TIME INTERVAL, SAID SECOND PULSE OCCURRING FIRST IN TIME DURING SAID SECOND TIME INTERVAL, SAID THIRD PULSE OCCURRING FIRST IN TIME DURING SAID THIRD TIME INTERVAL, AND MEANS FOR APPLYING SAID FIRST, SECOND AND THIRD PULSES TO SAID BISTABLE DEVICE TO PLACE SAID BISTABLE DEVICE IN SAID SECOND STABLE STATE.