Timing synchronization of LIDAR system to reduce interference

• US 10,338,201 B2
• Filed: 09/13/2016
• Issued: 07/02/2019
• Est. Priority Date: 09/17/2015
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Slobodyanyuk, Volodimir, Butterfield, Daniel
• Primary Examiner(s): Ratcliffe, Luke D
• Application Number:
  US15/263,613
• Publication Number:
  US 20170082737A1
• Time in Patent Office: 1,022 Days
• CPC Class Codes: G01S 17/08 for measuring distance only indirect measurement G01S17/46; active triangulation systems G01S17/48
• 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 7/484 Transmitters
• CPC Class Codes: G01S 7/497 Means for monitoring or calibrating

Abstract

An example method for use with a LIDAR system includes assigning a firing time of a laser included in the LIDAR system. The assignment of the firing time includes: (i) receiving a universal clock signal at the LIDAR system, where the universal clock signal common to one or more other LIDAR systems; (ii) synchronizing a system clock of the LIDAR system to the universal clock signal to generate a synchronized clock signal; and determining the firing time based on the synchronized clock signal to reduce interference with the one or more other LIDAR systems. The method also includes firing the laser at the firing time.

Claims

1. A method for use with a LIght Detection And Ranging (LIDAR) system, the method comprising:

assigning a firing time of a laser included in the LIDAR system, wherein assigning the firing time includes;

receiving a universal clock signal at the LIDAR system, the universal clock signal common to one or more other LIDAR systems;

synchronizing a system clock of the LIDAR system to the universal clock signal to generate a synchronized clock signal; and

determining the firing time based on the synchronized clock signal to reduce interference with the one or more other LIDAR systems, including

establishing a frame divided into a plurality of timeslots,

assigning one or more of the plurality of timeslots as the firing time for the LIDAR system,

obtaining a unique identifier number that is unique to the LIDAR system, and

applying a HASH algorithm to the unique identifier number to select which of the plurality of timeslots to assign as the firing time for the LIDAR system; and

firing the laser at the firing time.

2. The method of claim 1, wherein the universal clock signal is a coordinated universal time (UTC) signal.

3. The method of claim 2, wherein the UTC signal is obtained via GPS.

4. The method of claim 1, wherein the universal clock signal is a GPS time signal.

5. The method of claim 1, further comprising incrementing the firing time for the LIDAR system based on a number of elapsed frames multiplied by a duration of the frame.

6. The method of claim 1, wherein the plurality of timeslots includes guard timeslots interleaved with active timeslots, and wherein assigning one of the plurality of timeslots as the firing time for the LIDAR system comprises selecting only one or more of the active timeslots as the firing time.

7. The method of claim 1, wherein assigning the firing time of the laser further comprises:

determining a range of operation of the LIDAR system; and

adjusting a period of each of the plurality of timeslots based on the range of operation.

8. The method of claim 7, wherein determining the range of operation of the LIDAR system comprises:

obtaining location data specific to a current location of the LIDAR system, wherein determining the range of operation of the LIDAR system is based on the location data.

9. The method of claim 8, wherein the location data consists of at least one data selected from the group consisting of:

a physical location of the LIDAR system, a terrain profile proximate to the physical location of the LIDAR system, a traffic pattern for an area proximate to the physical location of the LIDAR system, a type of the physical location of the LIDAR system being an urban environment, the type of the physical location of the LIDAR system being a rural environment.

10. A LIght Detection And Ranging (LIDAR) system, comprising:

a laser;

memory adapted to store program code; and

a processing unit coupled to the memory to access and execute instructions included in the program code to direct the LIDAR system to;

assign a firing time of the laser, wherein the instructions to assign the firing time includes instructions to;

receive a universal clock signal at the LIDAR system, the universal clock signal common to one or more other LIDAR systems;

synchronize a system clock of the LIDAR system to the universal clock signal to generate a synchronized clock signal; and

determine the firing time based on the synchronized clock signal to reduce interference with the one or more other LIDAR systems, wherein the determining includes

establishing a frame divided into a plurality of timeslots,

assigning one or more of the plurality of timeslots as the firing time for the LIDAR system,

obtaining a unique identifier number that is unique to the LIDAR system, and

applying a HASH algorithm to the unique identifier number to select which of the plurality of timeslots to assign as the firing time for the LIDAR system; and

fire the laser at the firing time.

11. The LIDAR system of claim 10, wherein the universal clock signal is a coordinated universal time (UTC) signal.

12. The LIDAR system of claim 11, wherein the UTC signal is obtained via GPS.

13. The LIDAR system of claim 10, wherein the plurality of timeslots includes guard timeslots interleaved with active timeslots, and wherein the instructions to assign one of the plurality of timeslots as the firing time for the LIDAR system comprises instructions to select only one or more of the active timeslots as the firing time.

14. A LIght Detection And Ranging (LIDAR) system, comprising:

a laser;

means for assigning a firing time of a laser included in the LIDAR system, wherein the means for assigning the firing time includes;

means for receiving a universal clock signal at the LIDAR system, the universal clock signal common to one or more other LIDAR systems;

means for synchronizing a system clock of the LIDAR system to the universal clock signal to generate a synchronized clock signal; and

means for determining the firing time based on the synchronized clock signal to reduce interference with the one or more other LIDAR systems, the means for determining including

means for establishing a frame divided into a plurality of timeslots,

means for assigning one or more of the plurality of timeslots as the firing time for the LIDAR system,

means for obtaining a unique identifier number that is unique to the LIDAR system, and

means for applying a HASH algorithm to the unique identifier number to select which of the plurality of timeslots to assign as the firing time for the LIDAR system; and

means for firing the laser at the firing time.

15. The LIDAR system of claim 14, wherein the plurality of timeslots includes guard timeslots interleaved with active timeslots, and wherein the means for determining the firing time of the laser of the LIDAR system comprises means for selecting only one or more of the active timeslots as the firing time.