Device and method for detection of aircraft wire hazard

• US 6,208,270 B1
• Filed: 11/16/1998
• Issued: 03/27/2001
• Est. Priority Date: 11/17/1997
• Status: Expired due to Fees

• Current Assignee: Thermotrex Corporation (Thermo Fisher Scientific Incorporated)
• Original Assignee: Thermotrex Corporation (Thermo Fisher Scientific Incorporated)
• Inventors: Dunn, Murray
• Primary Examiner(s): SWARTHOUT, BRENT
• Application Number:
  US09/192,963
• Time in Patent Office: 862 Days
• Field of Search: 340/961, 340/968, 340/435, 340/903, 701/301, 342/29
• US Class Current: 340/961
• CPC Class Codes: B82Y 15/00 Nanotechnology for interacting, sensing or actuating, e.g. quantum dots as markers in protein assays or molecular motors
• CPC Class Codes: G01S 17/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S17/46
• CPC Class Codes: G01S 17/933 of aircraft or spacecraft
• CPC Class Codes: G01S 7/4812 transmitted and received beams following a coaxial path
• CPC Class Codes: G01S 7/4817 relating to scanning

Abstract

An optical hazard detection system for aircraft based on a dynamic parallax mechanism to alert the pilot of an object in the flight path by a selected amount of time in advance.

Claims

1. An optical detection system mounted on a moving vehicle, comprising:

(a) a light source operable to produce an optical probe beam;

(b) a beam scanning element, disposed relative to the light source to receive the probe beam and configured to rotate about a rotation axis to project the probe beam to trace a scanning pattern for detecting a reflecting object in the path of the probe beam, wherein the beam scanning element receives and directs the reflected probe beam from the object in a direction that correlates to a rotation angle of the scanning element and thereby a distance from the object to the vehicle, and wherein the beam scanning element is operable to adjust the size of a cone angle of the scanning pattern according to a traveling speed of the moving vehicle;

(c) a light detector located relative to the beam scanning element to receive at least a portion of the reflected probe beam at a location on the detector and to produce an electrical signal, wherein the location on the detector has information indicating the distance from the object to the vehicle; and

(d) an electronic unit connected to receive the electrical signal and configured to determine the distance from the object to the vehicle according to a time duration for the probe beam traveling to and from the object that is inferred from the reflected probe beam location on the detector.

2. A system as in claim 1, wherein the scanning element includes an image-inverting prism.

3. A system as in claim 2, wherein the image-inverting prism is a Dove prism.

4. A system as in claim 2, wherein the scanning element further includes a beam steering unit disposed in the optical path between the light source and the image-inverting prism and operable to adjust the direction of the probe incident to the image-inverting prism to control a cone angle of the output probe beam from the prism with respect to the moving direction of the vehicle according to the speed of the vehicle.

5. A system as in claim 1, wherein the beam scanning element is configured to maintain the scanning pattern not less than a profile of the vehicle at a detection distance along the moving direction of the vehicle.

6. A system as in claim 1, wherein the detector is configured to receive the reflected probe beam only when the object is spaced from the vehicle within a detection distance for the probe beam to travel within a predetermined time.

7. A system as in claim 6, wherein the scanning element is configured to maintain the size of the scanning pattern at the detection distance which varies with the speed of the vehicle.

8. A system as in claim 1, further comprising a spatial filtering element at the light detector to select only the reflected probe beam for detection when the reflecting object is within a certain distance from the vehicle at a given vehicle speed.

9. A system as in claim 8, wherein said spatial filtering element is further configured to select the reflected probe beam for detection when the reflecting object is within another distance from the vehicle at the given vehicle speed.

15. A system as in claim 1, wherein the cone angle of the probe beam is adjusted to increase with a decrease in the speed of the vehicle and to decrease with an increase in the speed of the vehicle.

16. A system as in claim 1, wherein the light detector has different detector areas associated with different distances between the vehicle and the object to produce different signals.

10. A method for detecting presence of an object that reflects light in the moving direction of a vehicle, comprising:

(a) projecting a probe beam to trace a scanning pattern ahead of the vehicle along the moving direction by using a beam scanning device;

(b) changing the size of a cone angle of the scanning pattern with a traveling speed of the moving vehicle so as to maintain the scanning pattern not less than a profile of the vehicle at a location ahead of the vehicle;

(c) receiving the reflected probe beam from the object by passing the reflected probe beam through the beam scanning device and directing the reflected probe beam to a light detector; and

(d) determining the distance of the object from the vehicle according to a location of the reflected probe beam on the light detector for a given speed of the vehicle and a scanning speed of the beam scanning device.

17. A method as in claim 10, further comprising generating a first warning signal when the distance between the object and vehicle is at a value greater than a minimum distance and a second warning signal when the distance is substantially equal to the minimum distance.

18. A method as in claim 10, further comprising:

spatially filtering the reflected probe beam to allow the reflected probe beam to reach the light detector only when the object is within a predetermined distance from the vehicle.

19. A method as in claim 10, wherein the cone angle of the probe beam is adjusted according to the speed of the vehicle to maintain a projected profile of the scanning pattern not less than a profile of the vehicle at a detection distance along the moving direction of the vehicle.

11. An optical detection system mounted on a moving vehicle, comprising:

(a) a light source operable to produce an optical probe beam;

(b) a beam scanning element, disposed relative to the light source to receive the probe beam and configured to rotate about a rotation axis to project the probe beam to trace a scanning pattern for detecting a reflecting object in the path of the probe beam, wherein the beam scanning element receives and directs the reflected probe beam from the object in a direction that correlates to a rotation angle of the scanning element and thereby a distance from the object to the vehicle, and wherein the beam scanning element is operable to adjust the size of a cone angle of the scanning pattern according to a traveling speed of the moving vehicle;

(c) a light detector located relative to the beam scanning element to receive at least a portion of the reflected probe beam at a location on the detector;

(d) a spatial filter disposed in front of the light detector to allow reflected light beams from certain angles to reach the light detector so as to select reflected light beams from the object only when the vehicle can reach the object at a current traveling speed within a predetermined time; and

(e) an electronic unit connected to receive electrical signals from the light detector and configured to produce a warning signal to alert the presence of the object.

12. A system as in claim 11, wherein the scanning element includes an image-inverting prism.

13. A system as in claim 12, wherein the image-inverting prism is a Dove prism.

14. A system as in claim 12, wherein the scanning element includes a beam steering unit disposed in the optical path between the light source and the image-inverting prism and operable to adjust the direction of the probe incident to the image-inverting prism to control a cone angle of the output probe beam from the prism with respect to the moving direction of the vehicle according to the speed of the vehicle.