# US 11,994,630 B2 · LIDAR waveform calibration system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,994,630 B2 - Document ID: US11994630B2 - Status: Granted - Kind: B2 - Application number: 17/827,679 - Filed: 2022-05-28 - Published: 2022-09-08 - Granted: 2024-05-28 - Earliest claimed: 2020-09-04 - Assignees: Aurora Operations, Inc. - Applicants: Aurora Operations, Inc. - Inventors: Andrew Steil Michaels; Sen Lin - Web page: https://patentgrep.com/patent/US11994630B2 ## CPC - G01S 7/497: Means for monitoring or calibrating - B60W 60/001: {Planning or execution of driving tasks} - G01S 7/4814: {of transmitters alone} - G01S 7/4915: Time delay measurement, e.g. operational details for pixel components (signal extraction and conditioning G01S7/493); Phase measurement - G01S 7/4917: {superposing optical signals in a photodetector, e.g. optical heterodyne detection} - G01S 7/493: Extracting wanted echo signals - G01S 17/06: Systems determining position data of a target - G01S 17/32: using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated - G01S 17/34: 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 - G01S 17/58: Velocity or trajectory determination systems; Sense-of-movement determination systems - G01S 17/931: of land vehicles - G05D 1/024: {in combination with a laser (lasers per se H01S)} - H01S 3/0057: {Temporal shaping, e.g. pulse compression, frequency chirping (soliton generation and propagation G02F1/3513, H01S3/063 and H01S3/108)} - B60W 2420/408: Radar; Laser, e.g. lidar - G01B 9/02003: using beat frequencies - G01B 9/0207: {Error reduction by correction of the measurement signal based on independently determined error sources, e.g. using a reference interferometer} - G01B 2290/60: Reference interferometer, i.e. additional interferometer not interacting with object - G01S 7/4911: Transmitters - H01S 3/0085: {Modulating the output, i.e. the laser beam is modulated outside the laser cavity} - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES - B60W: CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT - G05D: SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES - H01S: DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS ## Abstract A light detection and ranging (LIDAR) system includes a laser and a calibration unit. The laser is configured to generate a laser beam based on a particular laser waveform that is associated with at least one parameter of a plurality of parameters. The calibration unit is configured to determine a particular value for the at least one parameter of the plurality of parameters to compensate for distortion characteristics of the laser. The calibration unit is configured to determine the particular value based on an output frequency of the laser beam. The calibration unit is configured to update the particular laser waveform with the particular value of the at least one parameter of the plurality of parameters. ## Claims ### Claim 1 A light detection and ranging (LIDAR) system comprising: a laser configured to generate a laser beam based on a particular laser waveform that is associated with at least one parameter of a plurality of parameters, the at least one parameter defining at least one of shape or linearity of the particular laser waveform; and a calibration unit configured to, based on an output frequency of the laser beam, determine a particular value for the at least one parameter of the plurality of parameters to compensate for distortion characteristics of the laser, wherein determining the particular value for the at least one parameter comprises minimizing a value of a merit function, the merit function depending on the at least one parameter and quantifying at least one of linearity or shape of the particular laser waveform, wherein the calibration unit is further configured to update the particular laser waveform with the particular value of the at least one parameter of the plurality of parameters. ### Claim 2 (depends on 1) The LIDAR system of claim 1, further comprising: a digital to analog converter that is configured to drive the laser with the particular laser waveform to determine the output frequency of the laser beam. ### Claim 3 (depends on 1) The LIDAR system of claim 1, further comprising: an interferometer that is configured to output a reference signal, wherein the reference signal represents a fixed-distance propagation of the laser beam, wherein the calibration unit is configured to calculate the output frequency of the laser beam based on the reference signal from the interferometer. ### Claim 4 (depends on 1) The LIDAR system of claim 1, wherein compensation for the distortion characteristics includes reduction of the distortion characteristics of the laser, wherein the distortion characteristics of the laser are based on a difference between the particular laser waveform and the output frequency of the laser. ### Claim 5 (depends on 1) The LIDAR system of claim 1, wherein the plurality of parameters have initial values, wherein the calibration unit is configured to replace one or more of the initial values with one or more updated values. ### Claim 6 (depends on 1) The LIDAR system of claim 1, further comprising: an interferometer configured to provide an in-phase signal and a quadrature signal that are representative of a fixed-distance propagation of the laser beam, wherein the calibration unit is configured to receive the in-phase signal and the quadrature signal from the interferometer, wherein the calibration unit is configured to determine the output frequency of the laser beam based on the in-phase signal and the quadrature signal. ### Claim 7 An autonomous vehicle control system comprising: a light detection and ranging (LIDAR) system including: a laser configured to generate a laser beam based on a particular laser waveform that is associated with at least one parameter of a plurality of parameters, the at least one parameter defining at least one of shape or linearity of the particular laser waveform; and a calibration unit configured to, based on an output frequency of the laser beam, determine a particular value for the at least one parameter of the plurality of parameters to compensate for distortion characteristics of the laser, wherein determining the particular value for the at least one parameter comprises minimizing a value of a merit function, the merit function depending on the at least one parameter and quantifying at least one of linearity or shape of the particular laser waveform, wherein the calibration unit is further configured to update the particular laser waveform with the particular value of the at least one parameter of the plurality of parameters; and one or more processors to control the autonomous vehicle control system in response to the particular laser waveform at least partially updated by the calibration unit. ### Claim 8 (depends on 7) The autonomous vehicle control system of claim 7, further comprising: a digital to analog converter that is configured to drive the laser with the particular laser waveform to determine the output frequency of the laser beam. ### Claim 9 (depends on 7) The autonomous vehicle control system of claim 7, further comprising: an interferometer that is configured to output a reference signal, wherein the reference signal represents a fixed-distance propagation of the laser beam, wherein the calibration unit is configured to calculate the output frequency of the laser beam based on the reference signal from the interferometer. ### Claim 10 (depends on 7) The autonomous vehicle control system of claim 7, wherein compensation for the distortion characteristics includes reduction of the distortion characteristics of the laser, wherein the distortion characteristics of the laser are based on a difference between the particular laser waveform and the output frequency of the laser. ### Claim 11 (depends on 7) The autonomous vehicle control system of claim 7, wherein the plurality of parameters have initial values, wherein the calibration unit is configured to replace one or more of the initial values with one or more updated values. ### Claim 12 (depends on 11) The autonomous vehicle control system of claim 11, further comprising: memory, wherein the one or more processors are configured to store the one or more updated values to the memory to support retrieval of updates to the particular laser waveform. ### Claim 13 (depends on 7) The autonomous vehicle control system of claim 7, further comprising: an interferometer configured to provide an in-phase signal and a quadrature signal that are representative of a fixed-distance propagation of the laser beam, wherein the calibration unit is configured to receive the in-phase signal and the quadrature signal from the interferometer, wherein the calibration unit is configured to determine the output frequency of the laser beam based on the in-phase signal and the quadrature signal. ### Claim 14 An autonomous vehicle comprising: a light detection and ranging (LIDAR) system including: a laser configured to generate a laser beam based on a particular laser waveform that is associated with at least one parameter of a plurality of parameters, the at least one parameter defining at least one of shape or linearity of the particular laser waveform; and a calibration unit configured to, based on an output frequency of the laser beam, determine a particular value for the at least one parameter of the plurality of parameters to compensate for distortion characteristics of the laser, wherein determining the particular value for the at least one parameter comprises minimizing a value of a merit function, the merit function depending on the at least one parameter and quantifying at least one of linearity or shape of the particular laser waveform, wherein the calibration unit is further configured to update the particular laser waveform with the particular value of the at least one parameter of the plurality of parameters; and one or more processors to control the autonomous vehicle in response to the particular laser waveform at least partially updated by the calibration unit. ### Claim 15 (depends on 14) The autonomous vehicle of claim 14, wherein the calibration unit is configured to calibrate the laser while integrated in the autonomous vehicle. ### Claim 16 (depends on 14) The autonomous vehicle of claim 14, wherein compensation for the distortion characteristics includes reduction of the distortion characteristics of the laser, wherein the distortion characteristics of the laser are based on a difference between the particular laser waveform and the output frequency of the laser. ### Claim 17 (depends on 14) The autonomous vehicle of claim 14, further comprising: a digital to analog converter that is configured to drive the laser with the particular laser waveform to determine the output frequency of the laser beam. ### Claim 18 (depends on 14) The autonomous vehicle of claim 14, further comprising: an interferometer that is configured to output a reference signal, wherein the reference signal represents a fixed-distance propagation of the laser beam, wherein the calibration unit is configured to calculate the output frequency of the laser beam based on the reference signal from the interferometer.