Method and system for inflight refueling of unmanned aerial vehicles

• US 8,056,860 B2
• Filed: 08/10/2010
• Issued: 11/15/2011
• Est. Priority Date: 08/13/2007
• Status: Active Grant

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Garcia, Carlos, Davidson, Frederick, Small, James
• Primary Examiner(s): Dinh; Tien
• Assistant Examiner(s): BENEDIK, JUSTIN M
• Application Number:
  US12/806,377
• Publication Number:
  US 20100321011A1
• Time in Patent Office: 462 Days
• Field of Search: 244/135.A, 244/135.R, 244/1.TD
• US Class Current: 244/135.A
• CPC Class Codes: B64C 39/024 of the remote controlled vehicle type, i.e. RPV
• CPC Class Codes: B64D 39/00 Refuelling during flight filling or emptying fuel tanks B64D37/14
• CPC Class Codes: B64D 39/04 Adaptations of hose construction pipes in general F16L
• CPC Class Codes: B64U 10/25 Fixed-wing aircraft VTOL aircraft B64U10/20
• CPC Class Codes: B64U 50/11 using internal combustion piston engines
• CPC Class Codes: B64U 80/40 for two or more UAVs
• CPC Class Codes: G05D 1/104 involving a plurality of aircrafts, e.g. formation flying traffic control systems for aircraft G08G5/00

Abstract

A system and method for refueling unmanned aerial vehicles. The system is adapted to refuel a first unmanned aerial vehicle from a second unmanned aerial vehicle and includes an arrangement for flying the first and second vehicles to proximity within a predetermined range and for connecting an umbilical from the second vehicle to the first vehicle in flight. In the illustrative embodiment, the arrangement for connecting includes a targeting system for electromagnetically detecting a refueling receptacle on the first vehicle. The targeting system includes a first coil around a refueling receptacle on the first vehicle. A seeker is disposed at a first end of said umbilical on the second vehicle. The seeker includes three detector coils adapted to detect a magnetic signal from the first coil around the receptacle on the first vehicle. The coils are mounted such that the detector coils point in different directions. The outputs of the coils are processed to determine the direction and range to the UAV from the tanker UAV.

Claims

1. A tanker comprising:

an umbilical;

a seeker disposed at an end of the umbilical, the seeker including detector coils positioned to point in different directions and configured to detect magnetic signals from target coils of a fueling receptacle of a mission unmanned aerial vehicle (UAV) during flight; and

circuitry to determine a direction and a range to the fueling receptacle based on a signal output from different directional positions of the detector coils,

the fueling receptacle for refueling the mission UAV from the tanker during flight.

2. A tanker comprising:

an umbilical;

a seeker disposed at an end of the umbilical, the seeker including detector coils to detect magnetic signals from target coils of a fueling receptacle of a mission unmanned aerial vehicle (UAV) during flight; and

circuitry to determine a direction and a range to the fueling receptacle based on a signal output from the detector coils,

the fueling receptacle for refueling the mission UAV from the tanker during flight,

wherein the detector coils are positioned to point in different directions, and

wherein the circuitry to determine a direction and a range to the fueling receptacle of a mission UAV is configured to detect the magnetic signals of two or more separate and distinct frequencies emanating from the target coils, each frequency being associated with a different directional position of the target coils.

3. The tanker of claim 2 wherein the detector coils comprise a first detector coil pointing in a first direction, a second detector coil pointing in a second direction and a third detector coil pointing in a third direction.

4. The tanker of claim 3 further comprising an autopilot,

wherein the seeker includes maneuvering fins, and

wherein the autopilot is to provide short-range guidance commands for maneuvering the fins of the seeker to dock with the fueling receptacle of the mission UAV.

5. The tanker of claim 4 wherein the tanker is an unmanned aerial vehicle configured to refuel the mission UAV during flight.

6. The tanker of claim 5 further comprising:

an airframe, the umbilical being coupled to the airframe; and

a fuel tank for retaining fuel for transferring through the umbilical when docked with the fueling receptacle of the mission UAV.

7. A mission unmanned aerial vehicle (UAV) comprising:

a fueling receptacle;

two or more target coils disposed around the refueling receptacle; and

circuitry to excite the each target coil at separate and distinct frequencies to allow a seeker on an umbilical of a mission UAV to detect distinct magnetic signals emanating from each of the target coils for in-flight refueling,

wherein the circuitry to excite is configured to hold the signal strength of the target coils constant to allow the seeker to accurately estimate a direction and range to the refueling receptacle.

8. The mission UAV of claim 7 wherein the target coils comprise a first target coil and a second target coil, the second target coil being disposed between the first target coil and the fueling receptacle.

9. The mission UAV of claim 8 further comprising an umbilical, wherein the fueling receptacle is located at an end of the umbilical.

10. A method for refueling a first unmanned aerial vehicle from a second unmanned aerial vehicle, the method comprising:

flying the first and second vehicles to proximity within a predetermined range; and

connecting an umbilical from one vehicle to the other vehicle in flight, wherein connecting includes;

magnetically detecting a refueling receptacle of the first vehicle by;

exciting first and second target coils disposed around the fueling receptacle with first and second respective signals at first and second separate and distinct frequencies; and

detecting magnetic signals from the first and the second coils with first and second detector coils to determine a direction and a range to the fueling receptacle based on a signal output from the detector coils.

11. The method of claim 10 wherein connecting further includes holding signal strength of the target coils constant to allow the direction and range to be accurately estimated.