Laser range finding system using variable field of illumination flash lidar

• US 8,072,581 B1
• Filed: 01/19/2007
• Issued: 12/06/2011
• Est. Priority Date: 01/19/2007
• Status: Active Grant

• Current Assignee: Rockwell Collins, Inc. (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Rockwell Collins, Inc. (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Breiholz, Arlen E.
• Primary Examiner(s): ALSOMIRI, ISAM A
• Application Number:
  US11/655,437
• Time in Patent Office: 1,782 Days
• Field of Search: 356/4.01, 356/5.01, 356/5.15, 356/28, 356/29, 356/139.01, 359/399, 701/223
• US Class Current: 356/5.01
• 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 17/89 for mapping or imaging
• CPC Class Codes: G01S 7/51 Display arrangements

Abstract

The laser range finding system includes a light detection and ranging (LIDAR) sensor unit (SU) and a LIDAR processor unit (PU). The LIDAR SU is for transmitting light pulses and receiving resulting input light signals reflected from objects within the field of view of the SU. The LIDAR SU includes a flash LIDAR illuminating laser source for transmitting light pulses. The LIDAR illuminating laser source includes an illuminating laser and zoom optics operatively associated with the laser. A LIDAR receiver receives resulting input light signals reflected from the objects. The LIDAR receiver includes a sensor; and, a flash readout integrated circuit (IC). The flash readout IC measures the transit time of the light pulses. The LIDAR processor unit (PU) is operatively associated with the LIDAR SU and it utilizes flash LIDAR ranging. A power source is operatively coupled to the LIDAR PU. Zooming of the transmitted light pulses results in the received resulting input light signals illuminating a relatively reduced area of the frame. Thus, a flash LIDAR image of relatively reduced resolution but enhanced range is provided by utilization of the transit time measurements.

Claims

1. A laser range finding system, comprising:

a) a light detection and ranging (LIDAR) sensor unit (SU) for transmitting light pulses and receiving resulting input light signals reflected from objects within the field of view of the SU, said LIDAR SU comprising;

i) a flash LIDAR illuminating laser source for transmitting light pulses, said LIDAR illuminating laser source including an illuminating laser and zoom optics operatively associated with said laser; and

,

ii) a LIDAR receiver for receiving resulting input light signals reflected from the objects, said LIDAR receiver including;

a sensor;

a flash readout integrated circuit (IC); and

, receiver optics, said flash readout IC for measuring the transit time of said light pulses, said receiver optics not including zoom optics;

b) a LIDAR processor unit (PU) operatively associated with said LIDAR SU, said LIDAR PU utilizing flash LIDAR ranging; and

,

c) a power source operatively coupled to said LIDAR PU, wherein, zooming only the transmitted light pulses results in the received resulting input light signals illuminating a relatively reduced area of the frame, thus providing a flash LIDAR image of relatively reduced resolution but enhanced range by utilization of said transit time measurements.

2. The laser range finding system of claim 1, wherein said LIDAR receiver operates as a passive imager part of the time to allow an operator to point said sensor, allowing an area of interest to be centered in a frame.

3. The laser range finding system of claim 1, wherein said LIDAR illuminating laser source comprises an optical view finder coupled with said zoom optics.

4. The laser range finding system of claim 1, further comprising a computer system coupled to said LIDAR PU for receiving processed navigation and mapping information from said LIDAR PU and providing an optimized geo-referenced map of the path traversed, the laser range finding system operating as a navigation and mapping system, wherein said LIDAR PU comprises a LIDAR navigation processor unit (NPU) and said LIDAR SU comprises a LIDAR navigation sensor unit (NSU).

5. The laser range finding system of claim 4, wherein said LIDAR NSU comprises at least one imaging sensor selected from the group consisting of:

Electro-Optic (EO)/Infrared (IR);

Low Light Television (LLTV);

Synthetic Aperture Radar (SAR); and

, Ultra Wide Band (UWB).

6. The laser range finding system of claim 4, wherein said LIDAR NSU comprises at least one communications link allowing exchange of situational awareness data between multiple systems.

7. The laser range finding system of claim 4, wherein said LIDAR NPU solves a simultaneous localization and mapping (SLAM) problem using a thin junction tree filter, thereby correcting real time dead reckoning/inertial measurement unit (IMU) error drift.

8. The laser range finding system of claim 4, wherein said LIDAR NPU comprises at least one radio navigation unit selected from the group consisting of:

Very High Frequency Omni-directional Radio-range (VOR);

Automatic Direction Finder (ADF);

Tactical Air Navigation (TACAN); and

, Instrument Landing System (ILS).

9. The laser range finding system of claim 4, wherein said LIDAR NPU comprises a GPS navigation system.

10. The laser range finding system of claim 4, further comprising a foot sensor unit operatively connected to said LIDAR NSU and said LIDAR NPU for improving accuracy Dead Reckoning (DR).

11. The laser range finding system of claim 4, wherein said LIDAR NPU receives output signals from said LIDAR NSU and provides multiple frame averaging thereof for thermal noise reduction.

12. The laser range finding system of claim 11, wherein said providing of multiple frame averaging comprises utilizing a minimal frame rate that allows frame averaging noise reduction minimizing the need for sensor cooling.

13. The laser range finding system of claim 4, wherein said LIDAR NSU and said LIDAR NPU are integrated as a single system.

14. The laser range finding system of claim 1, wherein said LIDAR NSU and said LIDAR NPU are integrated as a single system, comprising:

a) an inertial measurement unit (IMU) for providing IMU sensor data;

b) a LIDAR light source for providing reflection data;

c) a reflection point manager for receiving i) said reflection data from said LIDAR light source, and ii) reflection point location error estimates, and using said reflection data and said error estimates for computing range and range rate measurements;

d) a Kalman filter for receiving said range and range rate measurements and current estimates of position, velocity and attitude, said Kalman filter providing said reflection point location error estimates to said reflection point manager; and

,

e) a strapdown navigator for receiving i) said IMU sensor data and ii) position, velocity, and attitude error estimates from said Kalman filter;

said strapdown navigator integrating said IMU sensor data and said position, velocity, and attitude error estimates to provide said current estimates of position, velocity and attitude,

wherein, said LIDAR light source is fixed to said IMU so that the measurements from said LIDAR light source may be easily represented in a known reference frame.

15. A method for laser range finding, comprising the steps of:

a) transmitting light pulses to objects within the field of view of a sensor unit (SU) of a light detection and ranging (LIDAR) sensor unit (SU), utilizing a flash LIDAR illuminating laser source including an illuminating laser and zoom optics operatively associated with said laser;

b) receiving resulting input light signals reflected from the objects utilizing a LIDAR receiver including;

a sensor;

a flash readout integrated circuit (IC) for measuring the transit time of said light signals; and

, receiver optics, said receiver optics not including zoom optics; and

,

c) utilizing flash LIDAR ranging via a LIDAR processor unit (PU) operatively associated with said LIDAR SU;

wherein, zooming only the transmitted light pulses results in the received resulting input light signals illuminating a relatively reduced area of the frame, thus providing a flash LIDAR image of relatively reduced resolution but enhanced range by utilization of said transit time measurements.

16. The method of claim 15, wherein said LIDAR receiver operates as a passive imager part of the time to allow an operator to point said sensor, allowing an area of interest to be centered in a frame.

17. The method of claim 15, wherein said step of transmitting light pulses comprises utilizing an optical view finder coupled with said zoom optics.

18. The method of claim 15, further comprising a step of utilizing a computer system coupled to said LIDAR PU for receiving processed navigation and mapping information from said LIDAR PU and providing an optimized geo-referenced map of the path traversed, the laser range finding system operating as a navigation and mapping system, wherein said LIDAR PU comprises a LIDAR navigation processor unit (NPU) and said LIDAR SU comprises a LIDAR navigation sensor unit (NSU).