Multi-line, high-definition LiDAR device and method with integrated direct spatial reference

Patent metadata

Field	Value
Publication number	US-11150349-B2
Application number	US-201816104129-A
Country	US
Kind code	B2
Filing date	Aug 16, 2018
Priority date	Aug 16, 2018
Publication date	Oct 19, 2021
Grant date	Oct 19, 2021

Abstract

The present disclosure relates to a FMCW Light Detection and Ranging system, a wave train of carrier frequency is modulated in narrow-band sequence, an delay interferometer with in-phase and quadrature outputs extracts the phase of this frequency modulation, and a coherent receiver with in-phase and quadrature outputs detects the phase of reflected light from a remote object, the ratio between two phases determines the distance of the remote object.

First claim

We claim:

1. A Light Detection and Ranging (LiDAR) system comprising,
a light source configured to emit light with a frequency modulated in narrow-band time sequence;
an optical transmitter waveguide configured to guide the emitted light toward a remote object;
an optical receiver waveguide configured to receive reflection light from the remote object;
a reference delay interferometer configured to interfere reference light with a delay of the reference light and produce a first in-phase output and a first quadrature output;
a coherent receiver configured to mix the emitted light with the reflection light and produce [an]a second in-phase output and a second quadrature output; and
a processor configured to calculate a first phase variance related to the modulated frequency based on the first in-phase output, the first quadrature output, and a second phase variance related to the modulated frequency based on second in-phase output and the second quadrature output,
wherein the reference light is derived from the emitted light.

2. The LiDAR system according to claim 1 , wherein the optical transmitter waveguide and the optical receiver waveguide are integrated in a duplex waveguide.

3. The LiDAR system according to claim 1 , further comprising optical lens arranged after the optical transmitter waveguide and the optical receiver waveguide.

4. The LiDAR system according to claim 1 , wherein the processor is further configured to derive a ratio between the first phase variance and the second phase variance and calculate the absolute distance of the remote object.

5. The LiDAR system according to claim 1 , wherein the second in-phase output and second quadrature output comprise a low frequency component representing the trending of phase change, the processor is configured to extract [a]the low frequency component of the second in-phase output and second quadrature output, and calculate a relative radial velocity of the remote object based on the low frequency component.

6. The LiDAR system according to claim 1 , further comprising a multiple line generation circuit configured to duplicate the output of the transmitter waveguide and/or the input of the receiver waveguide into multiple lines.

7. The LiDAR system according to claim 6 , further comprising multiple optical switches each corresponding to each of the multiple lines.

8. The LiDAR system according to claim 6 , further comprising a mechanical system configured to rotate and delivers the emitted light towards different orientations.

9. The LiDAR system according to claim 6 , further comprising an echo cancelling electrical circuit configured to mitigate unintended reflection from components within the system.

10. The LiDAR system according to claim 9 wherein the echo cancelling electrical circuit comprising, an echo detector coupled to the coherent receiver; and
a loopback control path configured to calculate an add-on current and apply the add-on current to a current received from the second in-phase output and the second quadrature output of the coherent receiver.

11. The LiDAR system according to claim 6 , further comprising an echo cancelling optical circuit, configured to mitigate unintended reflection from components within the system.

12. The LiDAR system according to claim 11 , wherein the echo cancelling optical circuit comprising:
an echo detector coupled to the coherent receiver;
a variable optical attenuator coupled to the optical transmitter waveguide and the optical receiver waveguide;
a phase adjustor coupled to the optical attenuator; and
a loopback control path configured to calculate an attenuation of the variable optical attenuator and a phase value of the phase adjustor so as to match the unintended reflection applied to the coherent receiver.

13. A light detection and ranging method comprising:
emiting light with a frequency modulated in narrow-band time sequence;
guiding the emitted light toward a remote object;
receiving reflection light from the remote object;
interfering reference light with a delay of the reference light and produce a first in-phase output and a first quadrature output;
mixing the emitted light with the reflection light and produce [an]a second in-phase output and a second quadrature output; and
calculating a first phase variance related to the modulated frequency based on the first in-phase output and the first quadrature output, and a second phase variance related to the modulated frequency based on second in-phase output and the second quadrature output;
wherein the reference light is derived from the emitted light.

14. The method according to claim 13 , further comprising deriving a ratio between the first phase variance and the second phase variance and calculate the distance of the remote object.

15. The method according to claim 14 , wherein the second in-phase output and second quadrature output comprise a low frequency component representing the trending of phase change, and the method further comprising extracting a low frequency component of the second in-phase output and second quadrature output, and calculating a relative radial velocity of the remote object based on the low frequency component.

Assignees

• Chen Wei
• Zhong Shan
• Zhang Jin
• Zhu Zhonghua
• Wu Lei

Inventors

• Chen Wei
• Zhong Shan
• Zhang Jin
• Zhu Zhonghua
• Wu Lei

Classifications

• G01S17/36 Primary

  with phase comparison between the received signal and the contemporaneously transmitted signal · CPC title

• G01S7/4911

  Transmitters · CPC title

• G01S17/34

  using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal · CPC title

• G01S7/497

  Means for monitoring or calibrating · CPC title

• G01S7/4917

  superposing optical signals in a photodetector, e.g. optical heterodyne detection · CPC title