Generation of LIDAR data

Patent metadata

Field	Value
Publication number	US-11536837-B2
Application number	US-201916419989-A
Country	US
Kind code	B2
Filing date	May 22, 2019
Priority date	Sep 5, 2018
Publication date	Dec 27, 2022
Grant date	Dec 27, 2022

Abstract

A LIDAR system includes a LIDAR chip configured to combine a LIDAR input signal and a reference signal so as to generate a composite light signal. The LIDAR input signal includes light reflected by an object located off of the LIDAR chip. The reference signal does not include light reflected by the object. The system also includes electronics configured to use the composite light signal to approximate a radial velocity between the LIDAR chip and the object. The radial velocity is approximated from a difference between a first distance and a second distance. The first distance is the distance between the object and the LIDAR chip at a first time. The second distance is the distance between the object and the LIDAR chip at a second time.

First claim

The invention claimed is:

1. A LIDAR system, comprising:
a LIDAR chip configured to combine light from a LIDAR input signal and a reference signal so as to generate a composite light signal,
the LIDAR input signal including light from a LIDAR output signal reflected by an object located off of the LIDAR chip, the LIDAR output signal having a carrier signal with an amplitude that is a function of a sinusoid with a chirped frequency, and
the reference signal not including light reflected by the object; and
electronics configured to use the composite light signal to approximate a radial velocity between the LIDAR chip and the object, the radial velocity being approximated from a difference between a first distance and a second distance,
the first distance being a distance between the object and the LIDAR chip at a first time, and
the second distance being a distance between the object and the LIDAR chip at a second time.

2. The system of claim 1 , wherein the LIDAR chip includes a waveguide that carries an outgoing LIDAR signal, the LIDAR input signal including light from the outgoing LIDAR signal and the reference signal including light from the outgoing LIDAR signal.

3. The system of claim 2 , wherein the LIDAR output signal includes light from the outgoing LIDAR signal.

4. The system of claim 3 , wherein the electronics are configured to direct the LIDAR output signal to different regions on a field of view.

5. The system of claim 4 , wherein the electronics direct the LIDAR output signal to a first region of the field of view while generating the generating the composite signal from which the first distance is approximated and while generating the composite signal from which the second distance is approximated; and
the electronics direct the LIDAR output signal to one or more second regions on the field of view between generating the composite signal from which the first distance is approximated and generating the composite signal from which the second distance is approximated.

6. The system of claim 4 , wherein the electronics direct the LIDAR output signal to a first region of the field of view while generating the generating the composite signal from which the first distance is approximated and while generating the composite signal from which the second distance is approximated; and
the electronics do not direct the LIDAR output signal to one or more second regions on the field of view between generating the composite signal from which the first distance is approximated and generating the composite signal from which the second distance is approximated.

7. The system of claim 1 , wherein the sinusoid has a frequency represented by f=f o +t*α or f=f o +α*DP*−t*α where α represents the rate of frequency change during a data period, f o represents a base frequency, and t represents time, and DP represents the duration of the data period.

8. The system of claim 7 , wherein the amplitude of the sinusoid is represented by: (M+N*cos(E+f*t)) 1/2 where M, N, and E are constants, M>0, N>0 and is a constant, M≥N.

9. The system of claim 1 , wherein the LIDAR output signal is configured such that when there is radial velocity between the LIDAR chip and the reflecting object, the LIDAR input signal has a frequency shift relative to a frequency of the LIDAR output signal but the frequency shift is not a function of the radial velocity between the LIDAR chip and the reflecting object.

10. The system of claim 1 , wherein the electronics are configured to generate the LIDAR output signal such that a contribution of a radial velocity between the LIDAR chip and the object to a frequency shift between the LIDAR input signal and the LIDAR output signal is less than 10% of what the contribution to the frequency shift would be with LIDAR output signal replaced by a continuous wave with the same frequency as the LIDAR output signal.

11. The system of claim 1 , wherein the electronics perform a real transform on the composite signal.

12. The system of claim 11 , wherein the electronics and use the result of the real transform to determine the first distance between the LIDAR chip and the reflecting object.

13. The system of claim 1 , wherein the LIDAR output signal has an electrical field represented by: (M+N*cos(E+f*t)) 1/2 cos(F*t) where M, N, and E are constants, M>0, N>0 and is a constant, M≥N, t represents time, f represents a frequency and cos(F*t) represents a base carrier signal.

14. The system of claim 13 , wherein the frequency is represented by f=f o +t*α or f=f o +α*DP*−t*α where α represents the rate of frequency change during a data period, f o represents a base frequency, and DP represents the duration of the data period.

15. The system of claim 1 , wherein the amplitude is a square root of the sinusoid.

16. A LIDAR system, comprising:
a LIDAR chip configured to combine light from a LIDAR input signal and a reference signal so as to generate a composite light signal,
the LIDAR input signal including light from a LIDAR output signal reflected by an object located off of the LIDAR chip, the LIDAR output signal having a carrier signal with an amplitude that is a function of a sinusoid,
the sinusoid having a frequency represented by f=f o +t*α or f=f o +α*DP*−t*α where α represents the rate of frequency change during a data period, f o represents a base frequency, and t represents time, and DP represents the duration of the data period, and
the reference signal not including light reflected by the object; and
electronics configured to use the composite light signal to approximate a radial velocity between the LIDAR chip and the object, the radial velocity being approximated from a difference between a first distance and a second distance,
the first distance being a distance between the object and the LIDAR chip at a first time, and
the second distance being a distance between the object and the LIDAR chip at a second time.

17. The system of claim 16 , wherein the LIDAR chip includes a waveguide that carries an outgoing LIDAR signal, the LIDAR input signal including light from the outgoing LIDAR signal and the reference signal including light from the outgoing LIDAR signal.

18. The system of claim 17 , wherein the LIDAR output signal includes light from the outgoing LIDAR signal.

19. The system of claim 18 , wherein the electronics are configured to direct the LIDAR output signal to different regions on a field of view.

20. The system of claim 19 , wherein the electronics direct the LIDAR output signal to a first region of the field of view while generating the generating the composite signal from which the first distance is approximated and while generating the composite signal from which the second distance is approximated; and
the electronics direct the LIDAR output signal to one or more second regions on the field of view between generating the composite signal from which the first distance is approximated and generating the composite signal from which the second distance is approximated.

21. The system of claim 19 , wherein the electronics direct the LIDAR output signal to a first region of the field of view while generating the generating the composite signal from which the first distance is approximated and while generating the composite signal from which the second distance is approximated; and
the electronics do not direct the LIDAR output signal to one or more second regions on the field of view between generating the composite signal from which the first distance is approximated a

Assignees

• Silc Tech Inc

Inventors

• Boloorian Majid
• Feng Dazeng
• Asghari Mehdi

Classifications

• G01S17/34 Primary

  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

• G01S7/4818

  using optical fibres · CPC title

• G01S17/58

  Velocity or trajectory determination systems; Sense-of-movement determination systems · CPC title

• G01S7/4917

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

• G01S7/4817

  relating to scanning · CPC title