Hyper temporal lidar with dynamic control of variable energy laser source

Patent metadata

Field	Value
Publication number	US-11460552-B1
Application number	US-202117482882-A
Country	US
Kind code	B1
Filing date	Sep 23, 2021
Priority date	Mar 26, 2021
Publication date	Oct 4, 2022
Grant date	Oct 4, 2022

Abstract

A lidar system that includes a variable energy laser source and transmits laser pulses produced by the variable energy laser source toward range points in a field of view can use a laser energy model to model the available energy in the variable energy laser source over time. The timing schedule for laser pulses fired by the lidar system can then be determined using energies that are predicted for the different scheduled laser pulse shots based on the laser energy model. This permits the lidar system to reliably ensure at a highly granular level that each laser pulse shot has sufficient energy to meet operational needs, including when operating during periods of high density/high resolution laser pulse firing. The laser energy model is capable of modeling a variable rate of energy buildup in the variable energy laser source per unit time.

First claim

What is claimed is:

1. A lidar apparatus comprising:
a variable energy laser source that exhibits a variable rate of energy buildup per unit time;
a mirror subsystem that defines where the lidar apparatus is aimed within a field of view, wherein the mirror subsystem is optically downstream from the variable energy laser source; and
a control circuit that dynamically schedules a variable rate firing of laser pulse shots by the variable energy laser source using a laser energy model as compared to a plurality of energy requirements relating to the laser pulse shots, wherein the laser pulse shots are transmitted from the variable energy laser source into the field of view via the mirror subsystem in accordance with the scheduled variable rate firing; and
wherein the laser energy model predictively (1) models a depletion of energy in the variable energy laser source in response to each scheduled laser pulse shot, (2) models a retention of energy in the variable energy laser source after scheduled laser pulse shots, and (3) models a buildup of energy in the variable energy laser source between scheduled laser pulse shots to support the dynamic scheduling of laser pulse shots in view of their energy requirements, wherein the modeled energy buildup reflects the variable rate of energy buildup per unit time for the variable energy laser source.

2. The apparatus of claim 1 wherein the variable energy laser source comprises an optical amplification laser source that exhibits the variable rate of energy buildup per unit time.

3. The apparatus of claim 2 wherein the optical amplification laser source comprises a pulsed fiber laser source.

4. The apparatus of claim 3 wherein the pulsed fiber laser source comprises a seed laser, a pump laser, and a fiber amplifier, wherein the pump laser deposits an amount of energy in the fiber amplifier that varies per unit time, and wherein the laser energy model models (1) seed energy for the pulsed fiber laser source over time and (2) energy stored in the fiber amplifier over time, wherein the modeled seed energy reflects the varying amount of energy deposited by the pump laser in the fiber amplifier per unit time.

5. The apparatus of claim 2 wherein the laser energy model (1) models depletion of energy in an optical amplifier of the optical amplification laser source in response to each scheduled laser pulse shot, (2) models retention of energy in the optical amplifier after scheduled laser pulse shots, and (3) models buildup of energy in the optical amplifier between scheduled laser pulse shots, wherein the modeled energy buildup reflects the variable rate of energy buildup per unit time for the optical amplifier.

6. The apparatus of claim 1 wherein the laser energy model includes a model for laser seed energy that reflects nonlinearities in laser seed energy over time.

7. The apparatus of claim 1 wherein the laser energy model models available laser energy for laser pulse shots at time intervals in a range between 10 nanoseconds to 100 nanoseconds.

8. The apparatus of claim 1 wherein the energy requirements include a minimum laser pulse energy.

9. The apparatus of claim 8 wherein the minimum laser pulse energy is non-uniform for the laser pulse shots.

10. The apparatus of claim 1 wherein the energy requirements include a maximum energy threshold relating to the laser source.

11. The apparatus of claim 1 wherein the control circuit updates the laser energy model based on feedback data indicative of actual energy amounts in the fired laser pulse shots.

12. The apparatus of claim 1 wherein the control circuit uses lookup tables based on the laser energy model to simulate energy characteristics for different time sequences of laser pulse shots.

13. The apparatus of claim 1 wherein the mirror subsystem comprises a first mirror and a second mirror, and wherein the control circuit (1) controls a scanning of the first and second mirrors to define where the lidar apparatus is aimed within the field view and (2) dynamically schedules a plurality of laser pulse shots that target selected range points in the field of view using the laser energy model as compared to energy requirements for the laser pulse shots targeting the selected range points in combination with a mirror motion model that models motion of the first mirror to define a sequence of time slots for firing the laser pulse shots which target the selected range points.

14. The apparatus of claim 13 wherein the control circuit (1) drives the first mirror to scan in a resonant mode and (2) drives the second mirror to scan in a point-to-point mode based on a plurality of range points to be targeted with the scheduled fired laser pulse shots.

15. The apparatus of claim 1 wherein the control circuit (1) dynamically schedules the variable rate firing of laser pulse shots by translating a plurality of range points in the field of view that are to be targeted with laser pulse shots into a shot list using the laser energy model as compared to the energy requirements and (2) provides firing commands to the variable energy laser source based on the shot list, wherein the shot list defines a timed sequence of the range points to be targeted with the scheduled laser pulse shots.

16. The apparatus of claim 15 wherein the laser energy model quantitatively predicts available laser energy amounts for laser pulse shots based on a history of prior laser pulse shots.

17. The apparatus of claim 1 wherein the control circuit comprises (1) a system controller and (2) a beam scanner controller;
wherein the system controller (1) generates a shot list using the laser energy model as compared to the energy requirements and (2) provides the shot list to the beam scanner controller, wherein the shot list defines a timed sequence of range points in the field of view to be targeted with the scheduled laser pulse shots; and
wherein the beam scanner controller (1) provides firing commands to the variable energy laser source based on the provided shot list and (2) dynamically controls a scanning of a mirror within the mirror subsystem based on the shot list.

18. A lidar apparatus comprising:
a first mirror that is scannable to define where the lidar apparatus is aimed along a first axis in a field of view;
a second mirror that is scannable to define where the lidar apparatus is aimed along a second axis in the field of view;
a control circuit; and
a variable energy laser source that is optically upstream from the first and second mirrors;
wherein the variable energy laser source exhibits a variable rate of energy buildup per unit time;
wherein the variable energy laser source generates laser pulses for transmission into the field of view via the first and second mirrors in response to firing commands from the control circuit;
wherein the control circuit (1) controls scanning of the first and second mirrors, (2) maintains a laser energy model that dynamically models available energy for laser pulses from the variable energy laser source over time, (3) determines, based on the laser energy model and energy levels for a plurality of laser pulses to be transmitted, a timing schedule that schedules the laser pulses for transmission, and (4) provides firing commands to the variable energy laser source based on the determined timing schedule to trigger generation of the laser pulses for transmission from the variable energy laser source into the field of view via the first and second mirrors; and
wherein the maintained laser energy model predictively (1) models a depletion of energy in the variable energ

Assignees

• Aeye Inc

Inventors

• Feru Philippe
• Dussan Luis
• Benscoter Joel
• Liang Alex
• Polishchuk Igor
• Steinhardt Allan

Classifications

• G01S17/10

  using transmission of interrupted, pulse-modulated waves (determination of distance by phase measurements G01S17/32) · CPC title

• G01S7/484 Primary

  Transmitters · CPC title

• G01S7/4816

  of receivers alone · CPC title

• G01S7/4817 Primary

  relating to scanning · CPC title

• G01S17/931

  of land vehicles · CPC title