Method and System for Optical Data Communication via Scanning Ladar

• US 20180239005A1
• Filed: 02/14/2018
• Published: 08/23/2018
• Est. Priority Date: 02/17/2017
• Status: Active Grant

• Current Assignee: AEye, Inc.
• Original Assignee: AEye, Inc.
• Inventors: Dussan, Luis Carlos, Steinhardt, Allan, Cook, David, Lacorte, Blair B.
• Granted Patent: US 11,092,676 B2
• Time in Patent Office: Days
• CPC Class Codes: G01S 17/06 Systems determining position data of a target
• 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 17/66 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 17/931 of land vehicles
• CPC Class Codes: G01S 2013/9316 combined with communication equipment with other vehicles or with base stations
• CPC Class Codes: G01S 7/006 using shared front-end circuitry, e.g. antennas G01S13/765, G01S13/825 take precedence
• CPC Class Codes: G01S 7/4816 of receivers alone
• CPC Class Codes: G01S 7/484 Transmitters
• CPC Class Codes: G01S 7/4861 Circuits for detection, sampling, integration or read-out
• CPC Class Codes: G01S 7/4865 Time delay measurement, e.g. time-of-flight measurement, time of arrival measurement or determining the exact position of a peak peak detection in noise, signal conditioning G01S7/487
• CPC Class Codes: G01S 7/487 Extracting wanted echo signals , e.g. pulse detection
• CPC Class Codes: G01S 7/4873 by deriving and controlling a threshold value
• CPC Class Codes: G01S 7/4876 by removing unwanted signals G01S7/495 takes precedence

Abstract

Disclosed herein are a number of example embodiments that employ controllable delays between successive ladar pulses in order to discriminate between “own” ladar pulse reflections and “interfering” ladar pulses reflections by a receiver. Example embodiments include designs where a sparse delay sum circuit is used at the receiver and where a funnel filter is used at the receiver. Also, disclosed are techniques for selecting codes to use for the controllable delays as well as techniques for identifying and tracking interfering ladar pulses and their corresponding delay codes. The use of a ladar system with pulse deconfliction is also disclosed as part of an optical data communication system.

Claims

1. A ladar system comprising:

a ladar transmitter comprising a plurality of scanable mirrors, the ladar transmitter configured to transmit a plurality of ladar pulses toward a plurality of range points via the scanable mirrors; and

a receiver configured to receive and process reflected ladar pulses to perform range point measurements; and

wherein the ladar transmitter is further configured to optically communicate message data to a destination via (i) a plurality of the ladar pulses that encode the message data and (ii) the scanable mirrors.

2. The system of claim 1 wherein the message data is encoded in the ladar pulses via a plurality of delays between ladar pulses.

3. The system of claim 2 wherein a first delay between ladar pulses encodes a “

0”

bit, and wherein a second delay between ladar pulses encodes a “

1”

bit.

4. The system of claim 3 further comprising a processor configured to (1) schedule a sequence of shots for ladar pulses that encode the message data via the first and second delays, and (2) control the ladar transmitter to optically communicate the message data to the destination via (i) the scheduled sequence of ladar pulses that encode the message data via the first and second delays and (ii) the scanable mirrors.

5. The system of claim 1 further comprising:

a sensor positioned to sense incoming light; and

a processor configured to (1) process data representative of the sensed incoming light, (2) identify the destination based on the processed data, and (3) instruct the ladar transmitter to transmit the message data to the identified destination via the encoded ladar pulses and the scanable mirrors.

6. The system of claim 5 further comprising:

a beam splitter positioned to receive incident light, re-direct a first portion of the incident light to the sensor, and re-direct a second portion of the incident light to the receiver, wherein the first portion corresponds to the sensed incoming light, and wherein the second portion corresponds to the reflected ladar pulses.

7. The system of claim 1 further comprising:

a processor and memory configured to (1) track laser dosages delivered by the ladar transmitter to a plurality of different locations, and (2) control the ladar transmitter based on the tracked laser dosages.

8. The system of claim 7 wherein the processor and memory are further configured to (1) maintain a dosage threshold, and (2) control the ladar transmitter based on the tracked laser dosages as compared to the dosage threshold.

9. The system of claim 8 wherein the processor and memory are further configured to (1) determine whether a scheduled shot for a ladar pulse targeted to a particular location would cause the tracked dosage for the particular location to exceed the dosage threshold, and (2) in response to a determination that the scheduled shot for the ladar pulse targeted to the particular location would cause the tracked dosage for the particular location to exceed the dosage threshold, control the ladar transmitter to not fire the scheduled ladar pulse shot.

10. The system of claim 8 wherein the processor and memory are further configured to (1) determine whether a scheduled shot for a ladar pulse targeted to a particular location would cause the tracked dosage for the particular location to exceed the dosage threshold, and (2) in response to a determination that the scheduled shot for the ladar pulse targeted to the particular location would cause the tracked dosage for the particular location to exceed the dosage threshold, control the ladar transmitter to decrease energy for the scheduled ladar pulse shot so as to cause the tracked dosage for the particular location to not exceed the dosage threshold

11. The system of claim 7 wherein the memory is configured to store a heat map data structure that tracks the laser dosages for the locations over a defined time window, the heat map data structure comprising a plurality of data values indexed by azimuth and elevation locations, wherein the data values represent the tracked laser dosage for the indexed azimuth and elevation locations.

12. The system of claim 1 further comprising:

a processor and memory configured to (1) process data representative of an environmental scene for the ladar transmitter to identify a keep away location for ladar pulses, and (2) control the ladar transmitter based on the identified keep away locations.

13. The system of claim 1 wherein the destination comprises another ladar system.

14. The system of claim 1 wherein the receiver is further configured to (1) receive ladar pulses from a remote system, wherein the received ladar pulses encode message data from the remote system, and (2) process the received encoded ladar pulses to extract the message data.

15. The system of claim 14 wherein the received ladar pulses encode the message data from the remote system via a plurality of delays between received ladar pulses, and wherein the receiver comprises a pulse deconfliction circuit configured to extract the delays between the received ladar pulses to determine the message data.

16. A method comprising:

scanning a plurality of mirrors;

transmitting a first plurality of ladar pulses toward a plurality of targeted range points via the scanning mirrors;

receiving and processing reflections of the first plurality of ladar pulses to perform range point measurements; and

transmitting a second plurality of ladar pulses toward a destination via the scanning mirrors, wherein the second plurality of ladar pulses encode message data.

17. The method of claim 16 further comprising:

encoding the message data in the second plurality of ladar pulses via a plurality of delays between ladar pulses.

18. The method of claim 17 wherein a first delay between ladar pulses encodes a “

0”

bit, and wherein a second delay between ladar pulses encodes a “

1”

bit.

19. The method of claim 18 further comprising:

scheduling a sequence of shots for the second plurality of ladar pulses via the first and second delays; and

wherein the step of transmitting the second plurality of ladar pulses comprises transmitting the scheduled sequence of ladar pulse shots via the scanning mirrors.

20. The method of claim 16 further comprising:

a beam splitter receiving incident light;

the beam splitter re-directing a first portion of the incident light to a sensor;

the beam splitter re-directing a second portion of the incident light to a receiver, wherein the second portion comprises reflections of the first plurality of ladar pulses;

the sensor sensing light corresponding to the re-directed incident light first portion;

a processor (1) processing data representative of the sensed light, (2) identifying the destination based on the processed data, and (3) controlling the step of transmitting the second plurality of ladar pulses to transmit the message data to the identified destination via the encoded ladar pulses and the scanning mirrors.

21. The method of claim 16 further comprising:

tracking laser dosages delivered by the transmitting steps to a plurality of different locations;

controlling the transmitting steps based on the tracked laser dosages.

22. The method of claim 21 wherein the controlling step comprises controlling the transmitting steps based on the tracked laser dosages as compared to a dosage threshold.

23. The method of claim 22 wherein the controlling step comprises performing, for a scheduled ladar pulse shot targeted to a particular location, at least one of (1) a cancellation of the scheduled ladar pulse shot, (2) a re-scheduling of the scheduled ladar pulse shot, and (3) an energy reduction for the scheduled ladar pulse shot in response to a determination that the scheduled ladar pulse shot would cause the tracked laser dosage for the particular location to exceed the dosage threshold.

24. The method of claim 21 wherein tracking step comprises building a heat map data structure that tracks the laser dosages for the locations over a time window, the heat map data structure comprising a plurality of data values indexed by azimuth and elevation locations, wherein the data values represent the tracked laser dosage for the indexed azimuth and elevation locations.

25. The method of claim 16 wherein the method steps are performed by a ladar system, and wherein the destination comprises another ladar system.

26. The method of claim 16 wherein the method steps are performed by a ladar system, and wherein the message data comprises at least one of (1) a delay code used by the ladar system to encode own ladar pulses, (2) a ladar point cloud for the ladar system, and (3) traffic data.

27. The method of claim 16 further comprising:

receiving ladar pulses from a remote system, wherein the received ladar pulses encode message data from the remote system;

processing the received encoded ladar pulses to extract the message data.

28. A method comprising:

scanning a plurality of mirrors;

transmitting a plurality of ladar pulses toward a plurality of targeted locations via the scanning mirrors;

receiving and processing reflections of the a plurality of the ladar pulses to perform a plurality of range point measurements;

tracking laser dosages delivered by the transmitting step to a plurality of different locations; and

controlling the transmitting step based on the tracked laser dosages.

29. The method of claim 28 wherein the controlling step comprises, for a scheduled ladar pulse shot targeted to a particular location, (1) determining whether the scheduled ladar pulse shot would cause the tracked laser dosage for the particular location to exceed a dosage threshold, and (2) in response to a determination that the scheduled ladar pulse shot would cause the tracked laser dosage for the particular location to exceed the dosage threshold, performing at least one of (1) a cancellation of the scheduled ladar pulse shot, (2) a re-scheduling of the scheduled ladar pulse shot, and (3) an energy reduction for the scheduled ladar pulse shot.

30. The method of claim 28 further comprising:

processing data representative of an environmental scene to identify a keep away location for ladar pulses; and

wherein the controlling step further comprises controlling the transmitting step based on the tracked laser dosages and the identified keep away location.