LIDARS

• US 20110040482A1
• Filed: 04/17/2009
• Published: 02/17/2011
• Est. Priority Date: 04/18/2008
• Status: Active Grant

• Current Assignee: BAE Systems Plc
• Original Assignee: BAE Systems Plc
• Inventors: Claxton, Christopher David, Brimble, Richard Arthur
• Granted Patent: US 8,744,741 B2
• Time in Patent Office: Days
• US Class Current: 701/301
• CPC Class Codes: G01C 3/08 Use of electric radiation detectors
• CPC Class Codes: G01S 17/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S17/46
• CPC Class Codes: G01S 2013/93271 in the front of the vehicles
• CPC Class Codes: G01S 7/4814 of transmitters alone
• CPC Class Codes: G08G 1/16 Anti-collision systems road vehicle drive control systems for predicting or avoiding probable or impending collision otherwise than by control of a particular sub-unit B60W30/08

Abstract

A Light Detection and Ranging (LIDAR) apparatus and method are disclosed having a rotatable light source enabled to emit a light ray, the light ray being emitted at a plurality of angular intervals; a reflection device, which can be parabolic in shape, and an analysis device for calculating a position at which one or more features are present based on the angle that the light ray was emitted and the time delay associated with the received reflected light, from a feature, wherein the analysis device takes into account the reflection of the light ray from the reflection device. In this manner, light rays may be reflected from heading in one direction to improve the resolution of the LIDAR in a second direction. Furthermore, where a parabolic reflector is used, positions of features can be calculated directly in a Cartesian coordinate system. Autonomous vehicles can use a LIDAR such as described herein to improve forward looking resolution in collision avoidance systems or terrain selection systems.

Claims

1. A Light Detection and Ranging (LIDAR) apparatus comprising:

a light source means for emitting a light ray at plural angular intervals, and arranged such that the light ray is at least partially rotatable about a rotational centre;

reflection means having a focal point, the reflection means positioned such that the rotational centre of the light ray is substantially located at the focal point and between a first angle and a second angle;

reception means for receiving reflected light from one or more features in a path of the light ray; and

analysis means for calculating a position at which one or more features are present based on an angle that the light ray was emitted and a time delay associated with received reflected light, wherein, when the light ray is emitted between the first and second angles, the analysis means takes into account reflection of the light ray from the reflection means.

2. A LIDAR as claimed in claim 1, wherein the reflection means is a single mirror.

3. A LIDAR as claimed in claim 1, wherein the reflection means is an array of mirrors.

4. A LIDAR as claimed in claim 1, wherein the reflection means characteristics and position are such that successive emitted light rays once reflected from the reflection means follow a non-diverging path.

5. A LIDAR as claimed in claim 1, wherein the reflection means is parabolic in shape for successively emitted light rays, once reflected from the reflection means, to follow a substantially parallel path.

6. A LIDAR as claimed in claim 1, wherein a position of each feature is calculated using a Cartesian coordinate system having a reference point at the focal point.

7. A LIDAR as claimed in claim 6, wherein the analysis means calculates an intercept point as a point at which the light ray is reflected from the reflection means.

8. A LIDAR as claimed in claim 1, wherein the light source means is rotatable through 360°

.

9. A LIDAR as claimed in claim 1, wherein the light source means is rotatable between a first and second position in an arc.

10. A LIDAR as claimed in claim 1, wherein the light source means is fixed with respect to the reflection means and the light ray is rotated between a first and second position in an arc through reflection from a rotatable light source mirror.

11. A LIDAR as claimed in claim 1, wherein the light source means and reception means are co-located at the focal point.

12. A LIDAR as claimed in claim 1, wherein the light source means is located at the focal point and the reception means is spaced apart from the focal point.

13. A LIDAR as claimed in claim 1, wherein the light source is at least one laser and the light ray is a laser beam.

14. A LIDAR as claimed in claim 1, wherein the light source is a single laser and the light ray is a laser beam.

15. A LIDAR as claimed in claim 1, comprising:

a refractive means for refracting light rays to reduce divergence from the light source means.

16. A LIDAR as claimed in claim 1, comprising:

directional movement means arranged to pan or tilt the apparatus, and for allowing light rays reflected from the reflection means to be aimed in a particular direction.

30. A vehicle collision avoidance system comprising:

a LIDAR according to claim 1.

31. A preferred terrain selection system comprising:

a LIDAR according to claim 1.

32. An autonomous vehicle comprising:

a vehicle collision avoidance system according to claim 30.

33. A driver assistance system for a vehicle comprising:

a vehicle collision avoidance system according to claim 30.

17. A method of operating a LIDAR having a light source means comprising:

(i) emitting a light ray from the light source means at regular intervals;

(ii) rotating the light ray about a rotational centre at a plurality of angular intervals;

(iii) reflecting the light ray from reflection means having a focal point, the reflection means being positioned such that the rotational centre of the light ray is substantially located at the focal point and between a first angle and a second angle;

(iv) receiving reflected light from one or more features in the path of the light ray; and

(v) calculating a position at which one or more features are present based on an angle that the light ray was emitted and a time delay associated with received reflected light, wherein, when the light ray is emitted between the first and second angles, the analysis means takes into account the reflection of the light ray from the reflection means.

18. A method as claimed in claim 17, wherein the reflection means is a single mirror.

19. A method as claimed in claim 17, wherein the reflection means is an array of mirrors.

20. A method as claimed in claim 17, wherein the at least one mirror is parabolic in shape for enabling laser beams reflected from the mirror to be substantially parallel.

21. A method as claimed in claim 17, wherein the position is calculated using a Cartesian coordinate system having a reference point at the focal point.

22. A method as claimed in claim 17, comprising:

calculating an intercept point as a point at which the light ray is reflected from the reflection means.

23. A method as claimed in claim 17, comprising:

rotating the light source means through 360°

.

24. A method as claimed in claim 17, comprising:

rotating the light source means between a first and second position in an arc.

25. A method as claimed in claim 17, wherein the light source means is fixed with respect to the reflection means, the method comprising:

rotating the light ray between a first and second position in an arc through reflection from a rotatable light source mirror.

26. A method as claimed in claim 17, wherein the light source means and reception means are co-located at the focal point.

27. A method as claimed in claim 17, wherein the light source means is located at the focal point and the reception means is spaced apart from the focal point.

28. A method as claimed in claim 17, wherein the light source is at least one laser and the light ray is a laser beam.

29. A method as claimed in claim 17, wherein the light source is a single laser and the light ray is a laser beam.