RANGE MEASUREMENT DEVICE

• US 20090046270A1
• Filed: 08/13/2007
• Published: 02/19/2009
• Est. Priority Date: 08/13/2007
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Hartman, Randolph G., Elgersma, Michael R.
• Granted Patent: US 7,852,463 B2
• Time in Patent Office: Days
• US Class Current: 356/5.10
• CPC Class Codes: G01S 17/10 using transmission of interrupted, pulse-modulated waves determination of distance by phase measurements G01S17/32
• CPC Class Codes: G01S 17/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S17/46
• CPC Class Codes: G01S 17/66 Tracking systems using electromagnetic waves other than radio waves
• CPC Class Codes: G01S 17/86 Combinations of lidar systems with systems other than lidar, radar or sonar, e.g. with direction finders
• CPC Class Codes: G01S 17/87 Combinations of systems using electromagnetic waves other than radio waves
• CPC Class Codes: G01S 17/894 3D imaging with simultaneous measurement of time-of-flight at a 2D array of receiver pixels, e.g. time-of-flight cameras or flash lidar
• CPC Class Codes: G01S 7/4808 Evaluating distance, position or velocity data
• CPC Class Codes: G01S 7/4814 of transmitters alone
• CPC Class Codes: G01S 7/4816 of receivers alone

Abstract

A range measurement device is disclosed. The device comprises a flash laser radar configured to produce a first laser pulse at a first time. The device receives, at a second time, reflections of the first laser pulse from at least one object within a 360 degree field of view. The device further comprises a timing electronics module, an image sensor in communication with the timing electronics module, a mirror element coupled between the image sensor and the laser radar, and a lens. The mirror element includes a first reflector configured to disperse the reflections of the first laser pulse within at least a portion of the 360 degree field of view and a second reflector configured to collect returning reflections of the first laser pulse from the at least one object into the image sensor. The lens is configured to focus the returning reflections onto the image sensor.

Claims

1. A range measurement device, comprising:

a flash laser radar configured to;

produce a first laser pulse at a first time, and

receive, at a second time, reflections of the first laser pulse from at least one object within a 360 degree field of view of the range measurement device;

a timing electronics module including one or more timers;

an image sensor in communication with the timing electronics module;

a mirror element coupled between the image sensor and the flash laser radar, the mirror element including;

a first reflector configured to disperse the reflections of the first laser pulse within at least a portion of the 360 degree field of view, and

a second reflector configured to collect returning reflections of the first laser pulse from the at least one object into the image sensor; and

a lens configured to focus the returning reflections of the first laser pulse onto the image sensor.

2. The device of claim 1, further comprising a processor coupled to an output of the image sensor, the processor operable to provide range, azimuth, and location measurements with three-dimensional images produced by the image sensor, and determine at least one of a relative location and an absolute location of a host vehicle having the range measurement device based on the range, azimuth, and location measurements provided.

3. The device of claim 1, wherein the timing electronics module is operable to:

monitor a sensitivity of the image sensor; and

control initiation of the first laser pulse to illuminate the target.

4. The device of claim 1, wherein the timing electronics module is further operable to measure signal transit timing of the first laser pulse as a propagation time between the initiation of the first laser pulse and the returning reflections.

5. The device of claim 1, wherein the image sensor is a charge-coupled device operable to measure a light intensity of the returning reflections.

6. The device of claim 1, where the first and second reflectors of the mirror element comprise a single reflector.

7. The device of claim 1, wherein the second reflector of the mirror element returns at least one three-dimensional image of a targeted object.

8. A navigation system, comprising:

a range measurement device operable to provide at least one of angles, ranges, and attitude data of at least one object, the range measurement device including;

a flash laser radar operable to produce a first laser pulse at a first time, wherein the range measurement device is configured to receive, at a second time, reflections of the first laser pulse from the at least one object within a 360 degree field of view of the range measurement device; and

a processor in communication with the range measurement device, the processor configured to;

track a range and an attitude based on an output of the range measurement device to the at least one object within a localized time period between the first and second times based on the reflections received from the at least one object, and

as additional reflections are received from the at least one object, record additional time periods to determine at least one of a current position and a current attitude of the range measurement device relative to the at least one object.

9. The system of claim 8, and further comprising at least one of an inertial sensor, a heading sensor, a speed sensor, a global positioning sensor, and an altimeter sensor in communication with the processor.

10. The system of claim 8, wherein the processor further comprises program instructions to determine at least one of an absolute position and an absolute attitude of the system based on the measurements to the at least one object with prior information including at least one known attitude and position.

11. The system of claim 8, wherein the processor further comprises program instructions to determine at least one of a range measurement to the at least one object, an azimuth measurement to the at least one object, and a location measurement of the at least one object.

12. A method for measuring range to determine position, the method comprising:

producing a first laser pulse with a laser radar at a first time dispersed over a 360 degree field of view;

receiving reflections of the first laser pulse from at least one object within the 360 degree field of view at a second time;

based on the returning reflections received at the second time, tracking at least one of a range and an attitude from a host vehicle having the laser radar to the at least one object within a localized time period between the first and second times; and

as additional laser pulse reflections are received, recording additional localized time periods to determine at least one of a current position and a current attitude of the host vehicle relative to the at least one object.

13. The method of claim 12, further comprising determining at least one of an absolute position and an absolute attitude of the host vehicle based on the reflections received and a known location of the at least one object.

14. The method of claim 12, further comprising:

synchronizing a range image of the at least one reflection of the flash laser pulse with the laser radar at the second time; and

determining a relative velocity between the range measurement device and the at least one object based on a localized time period between the first and second times.

15. The method of claim 14, wherein synchronizing the range image of the reflected tracking signal with the laser radar comprises determining at least one of a range measurement to the at least one object, an azimuth measurement to the at least one object, and a location measurement of the at least one object.

16. The method of claim 12, further comprising determining a relative range between the range measurement device and the at least one object.

17. The method of claim 12, wherein receiving the reflections further comprises determining a relative angle between the at least one object and the host vehicle based on relative transit times.

18. The method of claim 12, wherein tracking further comprises:

determining at least one of a relative position and relative attitude of the at least one object within the 360 degree field of view; and

determining at least one of an absolute position and absolute attitude of the at least one object when the absolute position of the at least one object is known.

19. The method of claim 12, wherein tracking further comprises:

determining a relative position angle between the at least one object and the host vehicle, wherein the at least one object is a targeted object;

determining at least a relative position and relative attitude to the targeted object; and

determining at least one of the absolute position and absolute attitude of the targeted object when the absolute position of the laser radar is known.

20. The method of claim 12, wherein recording the additional localized time periods comprises at least one of:

measuring the additional signal reflections to determine a current heading, pitch, and roll of the host vehicle; and

measuring the signal reflections to determine a location of the target relative to the host vehicle.