Flash LADAR system

• US 7,961,301 B2
• Filed: 05/11/2009
• Issued: 06/14/2011
• Est. Priority Date: 05/09/2008
• Status: Active Grant

• Current Assignee: BAE Systems Space & Mission Systems Incorporated (BAE Systems Plc)
• Original Assignee: Ball Aerospace & Technologies Corporation (Ball Corporation)
• Inventors: Huang, Xiaopei, Craig, Rex M., Gravseth, Ian J., Weimer, Carl S., Earhart, Ronald P., Grund, Christian J.
• Primary Examiner(s): ALSOMIRI, ISAM A
• Application Number:
  US12/464,009
• Publication Number:
  US 20100208244A1
• Time in Patent Office: 764 Days
• Field of Search: 356/4.01, 356/5.01
• US Class Current: 356/4.01
• CPC Class Codes: G01S 17/58 Velocity or trajectory determination systems; Sense-of-movement determination systems
• 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 17/88 Lidar systems specially adapted for specific applications
• 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 3/7867 Star trackers navigation using star trackers G01C21/025
• CPC Class Codes: G01S 7/4813 Housing arrangements
• CPC Class Codes: G01S 7/4814 of transmitters alone
• CPC Class Codes: G01S 7/4816 of receivers alone

Abstract

The present invention pertains in general to a single, integrated flash LADAR system and method. The system includes data processing hardware and software, a passive two-dimensional camera, a three-dimensional camera, a light source, and a common optical path. One or more star trackers can also be included. In addition, auxiliary components, such as an inertial measurement unit and a global positioning system receiver can be included. The system can be closely integrated with a critical algorithm suite that operates in multiple modes, in real-time to enable landing, docking, and navigation functions, such as Guidance, Navigation, and Control (GNC), Altimetry, Velocimetry, Terrain Relative Navigation (TRN), Hazard Detection and Avoidance (HDA), and dust penetration.

Claims

1. A LADAR system, comprising:

a common receive aperture;

a first optical sensor, wherein the first optical sensor is a three-dimensional focal plane array that receives a signal from the common receive aperture;

a second optical sensor, wherein the second optical sensor is a two-dimensional focal plane array that receives a signal from the common receive aperture;

shared electronics, wherein the first optical sensor and the second optical sensor are interconnected to the shared electronics.

2. The system of claim 1, further comprising:

a first beam splitter, wherein a received signal collected by the common receive aperture is divided into a first signal component and a second signal component by the first beam splitter, wherein the first signal component is provided to the first optical sensor, and wherein at least a portion of the second signal component is provided to the second optical sensor.

3. The system of claim 2, wherein the first beam splitter is a dichroic element, and wherein the first and second signal components include different signal wavelengths.

4. The system of claim 1, further comprising:

a third optical sensor, wherein the third optical sensor is a two-dimensional focal plane array.

5. The system of claim 4, wherein the third optical sensor operates in conjunction with a star tracker function.

6. The system of claim 4, wherein the third optical sensor receives a signal from a second receive aperture that is not aligned with the first and generally orthogonal.

7. The system of claim 4, further comprising:

a star tracker optic, wherein the third optical sensor is provided with a signal from the star tracker optic.

8. The system of claim 1, further comprising:

a light source;

transmit optics, wherein the transmit optics are operable to transmit a beam received from the light source.

9. The system of claim 8, further comprising:

a beam steering element, wherein the beam steering element is operable to selectively steer the beam transmitted by the transmit optics.

10. The system of claim 8, wherein the light source comprises a pulsed laser, pulsed for pulsed-mode operation and continuous-wave for continuous-mode operation.

11. The system of claim 1, further comprising:

an enclosure, wherein the first optical sensor, the second optical sensor, and the shared electronics are housed within the first enclosure.

12. The system of claim 1, wherein the shared electronics comprise a field programmable gate array.

13. The system of claim 1, wherein the common receiver aperture includes a zoom optic.

14. The system of claim 1, wherein for a frame of data for the three dimensional focal plane and for a corresponding frame of two-dimensional data a geolocation and pointing direction is associated.

15. The system of claim 1, further comprising:

A common processor, wherein the common processor provides at least one of dark count subtraction, background light subtraction, noise filtering, temporal centroiding, orthorectification, interpolation, and averaging.

16. A sensor system, comprising:

a shared receive aperture, including;

receive optics;

intensity control elements;

filters;

a primary dichroic mirror, wherein the dichroic mirror is in the optical path of the shared receive aperture and receives received signal light from the shared receive aperture;

a three-dimensional focal plane array, wherein a first component of the received signal light within a first range of wavelengths is a first one of passed by or reflected to the three-dimensional focal plane array by the dichroic mirror;

an imaging two-dimensional focal plane array, wherein at least a portion of a second component of the received signal light within a second range of wavelengths is a second one of passed by or reflected to the imaging two-dimensional array by the dichroic mirror;

a laser light source;

transmit optics, wherein the transmit optics receive light produced by the laser light source;

shared electronics, wherein the shared electronics are interconnected to and control operation of at least the intensity control elements, the three-dimensional focal plane array, the imaging two-dimensional focal plane array, and the laser light source;

a shared enclosure, wherein the primary dichroic mirror, the three-dimensional focal plane array, the imaging two-dimensional focal plane array, laser light source, and the shared electronics are housed in the shared enclosure, and wherein the shared receive aperture and the transmit optics are mounted to the shared enclosure.

17. The system of claim 16, further comprising:

a two-dimensional star tracker array.

18. The system of claim 17, further comprising:

a star tracker optic, wherein a signal from the star tracker optic is received by the two-dimensional star tracker array.

19. The system of claim 16, wherein the system provides sensory data for TRN, HRD, and velocimetry.

20. A method for operating a flash LADAR system, comprising:

first transmitting a laser beam;

receiving a reflected return signal from a target at a shared receive aperture;

directing the reflected return signal to a three-dimensional focal plane array;

receiving a passive signal at the shared receive aperture, wherein at least some of the passive return signal is received at the same time as the reflected return signal;

directing the passive return signal to a two-dimensional focal plane array;

obtaining a frame of three-dimensional image information;

obtaining a frame of two-dimensional image information within a time at which the frame of three-dimensional image information is obtained;

obtaining absolute position information;

combining the frame of three-dimensional image information with the frame of two-dimensional image information to obtain a combined frame;

associating the absolute position information with the combined frame;

after associating the absolute position information with the combined frame, second transmitting a laser beam, wherein the first transmitting a laser beam and the second transmitting a laser beam is separated in time by no more than 1/30 th of a second.