LIDAR with analog memory

• US 9,069,061 B1
• Filed: 07/19/2012
• Issued: 06/30/2015
• Est. Priority Date: 07/19/2011
• Status: Active Grant

• Current Assignee: BAE Systems Space & Mission Systems Incorporated (BAE Systems Plc)
• Original Assignee: Ball Aerospace & Technologies Corporation (Ball Corporation)
• Inventors: Harwit, Alex
• Primary Examiner(s): Ratcliffe, Luke
• Assistant Examiner(s): Abraham, Samantha K
• Application Number:
  US13/553,710
• Time in Patent Office: 1,076 Days
• Field of Search: 356/3.01, 356/3.09, 356/4.01, 356/4.07, 356/5.01, 356/5.09, 356/9, 356/625
• US Class Current: 1/1
• 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 7/4818 using optical fibres
• CPC Class Codes: G01S 7/4863 Detector arrays, e.g. charge-transfer gates

Abstract

LIDAR systems and methods are provided. More particularly, a distributed focal plane assembly is provided in which light collected by optical fibers is delivered to detectors on a separate substrate. Moreover, signals from detectors can be stored in analog memory on a different substrate from the detectors. Alternatively, light may be imaged onto detectors on one substrate and stored in analog memory on a different substrate. The detectors can be provided in a linear or one-dimensional array. A laser source can comprise a multiplexed laser source which provides a sequence of pulses separated in time and having different directions of propagation.

Claims

1. A LIDAR system, comprising:

a plurality of detectors;

a plurality of optical inputs, wherein each detector in the plurality of detectors is associated with an optical input, and wherein the optical inputs are arranged to form a focal plane array;

a plurality of analog memory units, wherein each analog memory unit is electrically interconnected to a detector, wherein each analog memory unit occupies an area that is larger than an area occupied by each detector, wherein an area of at least some of the analog memory units is not registered with an area of an electrically interconnected detector, wherein each analog memory has one analog input and one analog output, and wherein the detectors and the analog memory units are on separate substrates.

2. The system of claim 1, comprising:

a plurality of optical fibers interconnected to a first substrate, wherein each optical fiber in the plurality of optical fibers has a first end and a second end, wherein the first ends of the optical fibers are arranged to form the focal plane array, wherein the plurality of detectors are interconnected to a second substrate, wherein the second end of each of the optical fibers included in the plurality of optical fibers of the focal plane array is associated with a detector, and wherein each optical fiber included in the plurality of optical fibers is operative to carry photons collected at a first end of the optical fiber to the detector associated with the second end of the optical fiber.

3. The system of claim 1, wherein each analog memory unit is electrically interconnected to a detector by a wire bond.

4. The system of claim 1, wherein each analog memory unit is electrically interconnected to a detector through an amplifier.

5. The system of claim 1, wherein the analog memory units are disposed on a plurality of substrates.

6. The system of claim 1, wherein the analog memory units are composed of switched capacitor arrays.

7. The system of claim 1, wherein the detectors include a plurality of photon sensitive pixels arranged to form a one-dimensional focal plane array, wherein each photon sensitive pixel includes a plurality of Geiger mode photo-detectors electrically connected in parallel, wherein the photon sensitive pixels are substantially rectangular with the shorter side of the photon sensitive pixels parallel to a line along which the one-dimensional focal plane array extends.

8. A LIDAR system, comprising:

a plurality of photon sensitive pixels, wherein the photon sensitive pixels are arranged to form a one-dimensional focal plane array, wherein the photon sensitive pixels are substantially rectangular, and wherein a shorter side of each of the photon sensitive pixels is parallel to a line along which the one-dimensional focal plane array extends;

a plurality of Geiger mode photo-detectors, wherein each photon sensitive pixel includes a plurality of Geiger mode photo-detectors that are electrically connected in parallel.

9. The system of claim 8, wherein the Geiger mode photo-detectors are substantially uniformly distributed within the photon sensitive pixels.

10. The system of claim 8, wherein the Geiger mode photo-detectors include Geiger mode avalanche photodiodes.

11. The system of claim 8, further comprising:

a beam splitter, wherein the beam splitter passes a first proportion of received light to the photon sensitive pixels in the one-dimensional focal plane array, wherein the beam splitter passes a second proportion of received light to a second plurality of photon sensitive pixels in a second one-dimensional focal plane array, and wherein the first and second proportions are different from one another.

12. The system of claim 8, further comprising:

a plurality of analog memory units, wherein each analog memory unit is electrically interconnected to the output of a photon sensitive pixel, wherein each analog memory unit occupies an area that is larger than an area of a photon sensitive pixel, wherein each analog memory unit is not registered with an area of a photon sensitive pixel, and wherein each analog memory has one analog input and one analog output.

13. The system of claim 12, wherein the photon sensitive pixels and analog storage elements are on separate substrates.

14. A LIDAR system, comprising:

an outgoing optical pulse generation system, wherein the outgoing optical pulse generation system generates sets of optical pulses, wherein there is a precise timing for each of the optical pulses within a set, wherein each of the optical pulses in the set is propagated at a different predetermined angle and at a different time, wherein a time delay between each of the optical pulses within the set is arranged to be larger than the time for light to travel roundtrip across a largest feature of a target in a direction normal to the LIDAR system; and

a LIDAR receiver, comprising a plurality of analog memory units, wherein each analog memory unit is electrically interconnected to a detector, wherein each analog memory unit occupies an area that is larger than an area of a detector, wherein an area of at least some of the analog memory units is not registered with an area of an electrically interconnected detector, wherein each analog memory unit has one analog input and one analog output, and wherein the detectors and analog memory units are on separate substrates.

15. The system of claim 14, wherein the outgoing pulse generation system includes:

a light source;

a primary optical fiber;

a plurality of taps or intervals along the primary optical fiber;

a plurality of output optical fibers, wherein each tap is interconnected to a first end of an output fiber; and

a beam shaping element.

16. The system of claim 14, wherein a plurality of lasers are used to generate the optical pulses within a set.

17. The system of claim 14, further comprising:

a plurality of optical fibers interconnected to a first substrate, wherein each optical fiber in the plurality of optical fibers has a first end and a second end, wherein the first ends of the optical fibers are arranged to form a focal plane array;

a plurality of detectors interconnected to a second substrate, wherein each of the second ends of the optical fibers included in the plurality of optical fibers of the focal plane array is associated with a detector included in the plurality detectors, wherein each optical fiber included in the plurality of optical fibers is operative to carry photons collected at a first end of the optical fiber to the detector associated with the second end of the optical fiber;

a plurality of analog memory units, wherein each analog memory unit is electrically interconnected to a detector included in the plurality detectors.

18. The system of claim 14, wherein the detectors include a plurality of Geiger mode photo-detectors electrically connected in parallel, wherein the Geiger mode photo-detectors are arranged to form a photon sensitive pixel;

a plurality of photon sensitive pixels, wherein the pixel optical inputs are arranged to form a one-dimensional focal plane array, wherein the photon sensitive pixels are substantially rectangular with the shorter side of the photon sensitive pixels parallel to the one-dimensional focal plane array.