Safe emergency landing of a UAV

A powered unmanned aerial vehicle (UAV) operable to perform an autonomous safe emergency landing in the event of an engine failure, said UAV comprising:

• a flight control system for controlling the flight of said UAV, said flight control system comprising a processing unit;
• a safe emergency landing system coupled with said flight control system, said safe emergency landing system comprising a storage device readable by said processing unit of said flight control system, tangibly embodying a program of instructions executable by said processing unit to perform method procedures for safe emergency landing of said unmanned aerial vehicle in the event of an engine failure, the method procedures comprising:
• generating a landing approach trajectory, comprising:
• a downwind leg, initiating at an initiation point of said trajectory, said downwind leg directed toward a first direction of a runway;
• an upwind leg, extending along said runway and terminating at a selected touchdown point located on said runway, said upwind leg being substantially parallel to said downwind leg and directed toward a second direction of said runway opposite to said first direction;
• and
• a U-turn leg, joining between said downwind leg and said upwind leg;
• providing said landing approach trajectory to said flight control system, for directing said UAV to said initiation point to follow said downwind leg;
• repeatedly determining a glide ratio of said UAV, based on current flight conditions of said UAV;
• repeatedly determining a current turning point along said downwind leg for landing said UAV at said selected touchdown point, said U-turn leg initiating at said current turning point, wherein the determination of said current turning point is based on the determined glide ratio and is performed each time with respect to a precedingly determined turning point;
• repeatedly determining a touchdown point corresponding to said current turning point, based on said determined glide ratio, wherein said procedure of determining a current turning point is performed with respect to the discrepancy between:
• (i) the touchdown point that was precedingly determined in correspondence with the precedingly determined turning point, and (ii) said selected touchdown point;
• repeatedly providing said current turning point to said flight control system, for directing said UAV to glide towards said current turning point;
• and
• when said UAV arrives at said current turning point, indicating to said flight control system to direct said UAV to follow said U-turn leg and said upwind leg of said landing approach trajectory, for landing said UAV safely along said runway at said selected touchdown point.

A system for mounting on a powered unmanned aerial vehicle (UAV) to allow safe emergency landing of said UAV in the event of an engine failure, said system coupled with a flight control system of said UAV, said system comprising:

• a storage device readable by a processing unit of said flight control system, tangibly embodying a program of instructions executable by said processing unit to perform method procedures comprising:
• generating a landing approach trajectory, comprising:
• a downwind leg, initiating at an initiation point of said trajectory, said downwind leg directed toward a first direction of a runway;
• an upwind leg, extending along said runway and terminating at a selected touchdown point located on said runway, said upwind leg being substantially parallel to said downwind leg and directed toward a second direction of said runway opposite to said first direction;
• and
• a U-turn leg, joining between said downwind leg and said upwind leg;
• providing said landing approach trajectory to said flight control system, for directing said UAV to said initiation point to follow said downwind leg;
• repeatedly determining a glide ratio of said UAV, based on current flight conditions of said UAV;
• repeatedly determining a current turning point along said downwind leg for landing said UAV at said selected touchdown point, said U-turn leg initiating at said current turning point, wherein the determination of said current turning point is based on said determined glide ratio and is performed each time with respect to a precedingly determined turning point;
• repeatedly determining a touchdown point corresponding to said current turning point, based on said determined glide ratio, wherein said procedure of determining a current turning point is performed with respect to the discrepancy between:
• (i) the touchdown point that was precedingly determined in correspondence with the precedingly determined turning point, and (ii) said selected touchdown point;
• repeatedly providing said current turning point to said flight control system, for directing said UAV to glide towards said current turning point;
• and
• when said UAV arrives at said current turning point, indicating to said flight control system to direct said UAV to follow said U-turn leg and said upwind leg of said landing approach trajectory, for landing said UAV safely along said runway at said selected touchdown point.