Apparatus, method and system for fluid-motion-powered modulation of a retroreflector for remote position sensing

• US 6,669,145 B1
• Filed: 12/30/2002
• Issued: 12/30/2003
• Est. Priority Date: 12/30/2002
• Status: Expired due to Fees

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Green, Samuel I.
• Primary Examiner(s): Barefoot, Galen L.
• Application Number:
  US10/331,810
• Time in Patent Office: 365 Days
• Field of Search: 244/135.R, 244/135.A, 244/161, 244/115, 244/116, 356/5, 356/152, 356/139.03, 356/141.5, 250/206.1, 250/206.2, 348/117, 359/291, 359/223, 359/292, 359/298, 359/846
• US Class Current: 244/135.00A
• CPC Class Codes: B64D 39/00 Refuelling during flight filling or emptying fuel tanks B64D37/14
• CPC Class Codes: G01S 17/74 Systems using reradiation of electromagnetic waves other than radio waves, e.g. IFF, i.e. identification of friend or foe
• CPC Class Codes: G01S 5/16 using electromagnetic waves other than radio waves
• CPC Class Codes: G02B 5/122 cube corner, trihedral or triple reflector type

Abstract

A fluid-motion-powered modulated reflector apparatus is provided that modulates the frequency of a reflected radiation signal. Passing the apparatus through a fluid such as air causes rotational velocity of a chopping wheel or, in some instances, a polarizing filter rotatably connected to propeller blades. The radiation signal is modulated by the blocking effect of a chopping wheel or a fixed polarizing filter and a rotating polarizing filter. The apparatus also can include a frequency selector to control the rotational velocity of the chopping wheel or rotatable polarizing filter. A fluid-motion-powered modulated reflector system may include an array of fluid-motion-powered modulated reflectors, each differently modulated by a frequency selector to allow a position sensor, such as a duo-lateral photodiode position sensing detector, and position determining system, to locate and determine the position of each individual retroreflector simultaneously. This system can be used for aerial refueling of unmanned combat air vehicles.

Claims

1. A fluid-motion-powered modulated reflector apparatus comprising:

a reflector for reflecting at least a portion of a radiation signal incident thereon;

a chopping wheel disposed between a source of the radiation signal and said reflector; and

a propeller that rotates in response to the passage of fluid thereover, connected to said chopping wheel to facilitate rotation thereof.

2. The apparatus of claim 1, wherein said reflector comprises a retroreflector.

3. The apparatus of claim 1, wherein said reflector comprises a corner-cube retroreflector.

4. The apparatus of claim 1, wherein said reflector is an array of retroreflectors, a reflective tape, or a reflective coating.

5. The apparatus of claim 1, further comprising a shaft to which said chopping wheel is mounted.

6. The apparatus of claim 1, wherein said fluid is air.

7. The apparatus of claim 1, further comprising a frequency selector to control the speed of rotation of said chopping wheel such that the radiation signal is modulated by said chopping wheel in accordance with the speed of rotation of said chopping wheel.

8. The apparatus of claim 7, wherein said frequency selector comprises a governor.

9. A method of modulating a radiation signal with a chopping wheel having a propeller connected thereto, comprising the steps of:

passing said propeller through a fluid to cause rotation of said chopping wheel;

controlling an angular velocity of said chopping wheel;

propagating at least a portion of an incident radiation signal through said chopping wheel; and

reflecting at least a portion of the incident radiation signal to produce a reflected radiation signal; and

propagating the reflected radiation signal through said chopping wheel.

10. The method of claim 9, wherein controlling the angular velocity of said chopping wheel comprises limiting a maximum rotational velocity of said chopping wheel.

11. A system for determining relative positions of first and second in-flight objects, comprising:

a source of radiation carried by said first object;

at least one fluid-motion-powered modulated reflector, mounted on said second object for reflecting a radiation signal, wherein said fluid-motion-powered modulated reflector comprises;

a reflector for reflecting at least a portion of a radiation signal incident thereon;

a chopping wheel disposed between a source of the radiation signal and said reflector; and

a propeller that rotates in response to the passage of fluid thereover, connected to said chopping wheel to facilitate rotation thereof; and

a detector, mounted on said first object, to receive the reflected radiation signal.

12. The system of claim 11, wherein said detector is a radiation detector.

13. The system of claim 11, further comprising a position determining system coupled to said detector.

14. The system of claim 11, wherein said fluid-motion-powered modulated reflector further comprises a frequency selector to control the speed of rotation of said chopping wheel such that the radiation signal is modulated by said chopping wheel in accordance with the speed of rotation of said chopping wheel.

15. The system of claim 11, comprising a plurality of fluid-motion-powered modulated reflectors.

16. The system of claim 15, wherein said frequency selector of each fluid-motion-powered modulated reflector controls the speed of rotation of said chopping wheel such that the radiation signal is modulated by said chopping wheel in accordance with the speed of rotation of said chopping wheel.

17. The system of claim 15, wherein said reflectors are positioned in a predetermined array and predisposed in a direction to reflect the radiation signals.

18. The system of claim 17, wherein each frequency selector controls the speed of rotation of said chopping wheel such that the radiation signal is modulated by said chopping wheel in accordance with the speed of rotation of said chopping wheel to be predetermined and different from any other reflected radiation signal modulated in said array.

19. The system of claim 11, wherein said first object is a refueling aircraft and said second object is a tanker aircraft.

20. The system of claim 11, wherein said first object is an unmanned combat air vehicle.

21. A fluid-motion-powered modulated reflector apparatus comprising:

a reflector for reflecting at least a portion of a radiation signal incident thereon;

a rotatable polarizing filter disposed between a source of the radiation signal and said reflector;

a propeller that rotates in response to the passage of fluid thereover connected to said rotatable polarizing filter to facilitate rotation therewith; and

a fixed polarizing filter covering the reflective face of said reflector and disposed between said rotatable polarizing filter and said reflector or disposed in front of said rotatable polarizing filter and said reflector.

22. The apparatus of claim 21, further comprising a frequency selector to control the speed of rotation of said propeller such that the radiation signal is modulated by said rotatable polarizing filter in accordance with the speed of rotation of said propeller.

23. The apparatus of claim 21, wherein said reflector is a retroreflector.

24. The apparatus of claim 21, wherein said reflector is a corner-cube retroreflector.

25. The apparatus of claim 21, wherein said reflector is an array of retroreflectors, a reflective tape, or a reflective coating.

26. The apparatus of claim 21, further comprising a shaft to which said rotatable polarizing filter and said frequency selector are mounted.

27. The apparatus of claim 21, wherein said frequency selector is a governor.

28. A method of modulating a radiation signal with a rotatable polarizing filter having a propeller connected thereto, comprising the steps of:

passing said propeller through a fluid to cause rotation of said rotatable polarizing filter;

controlling an angular velocity of said polarizing filter;

propagating an incident radiation signal through said rotatable polarizing filter and a fixed polarizing filter such that the radiation signal is polarized;

reflecting at least a portion of the radiation signal to produce a reflected radiation signal; and

propagating the reflected radiation signal through said rotatable polarizing filter and said fixed polarizing filter.

29. The method of claim 28, wherein controlling the angular velocity of said rotatable polarizing filter comprises limiting a maximum angular velocity of said rotatable polarizing filter.

30. A system for determining relative positions of first and second in-flight objects, comprising:

a source of radiation carried by said first object;

at least one fluid-motion-powered modulated reflector, mounted on said second object for reflecting a radiation signal, wherein said fluid-motion-powered modulated reflector comprises;

a reflector for reflecting at least a portion of the radiation signal incident thereon;

a rotatable polarizing filter disposed between a source of the radiation signal and said reflector;

a fixed polarizing filter covering the reflective face of said reflector and disposed between said rotatable polarizing filter and said reflector or disposed in front of said rotatable polarizing filter and said reflector; and

a propeller that rotates in response to the passage of fluid thereover connected to said rotatable polarizing filter to facilitate rotation therewith; and

a detector, mounted on said first object, to receive the reflected radiation signal.

31. The system of claim 30, wherein said detector is a radiation detector.

32. The system of claim 30, further comprising a position determining system coupled to said detector.

33. The system of claim 30, wherein said fluid-motion-powered modulated reflector further comprises a frequency selector to control the speed of rotation of said polarizing filter such that the radiation signal is modulated by said rotatable polarizing filter in accordance with the speed of rotation of said rotatable polarizing filter.

34. The system of claim 30, comprising a plurality of fluid-motion-powered modulated reflectors.

35. The system of claim 34, wherein said frequency selector of each fluid-motion-powered modulated reflector controls the speed of rotation of said rotatable polarizing filter such that the radiation signal is modulated by said rotatable polarizing filter in accordance with the speed of rotation of said rotatable polarizing filter.

36. The system of claim 34, wherein said reflectors are positioned in a predetermined array and predisposed to reflect the radiation signal.

37. The system of claim 36, wherein said frequency selector of each fluid-motion-powered modulated reflector controls the speed of rotation of said rotatable polarizing filter such that the radiation signal is modulated by said rotatable polarizing filter in accordance with the speed of rotation of said rotatable polarizing filter to be different from any other reflected radiation signal modulated in said array.

38. The system of claim 30, wherein said first object is a refueling aircraft and said second object is a tanker aircraft.

39. The system of claim 30, wherein said first object is an unmanned combat air vehicle.