# US 2021/0278538 A1 · Lidar sensing arrangements > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0278538 A1 - Document ID: US20210278538A1 - Status: Published application - Kind: A1 - Application number: 16/810,269 - Filed: 2020-03-05 - Published: 2021-09-09 - Earliest claimed: 2020-03-05 - Assignees: Santec Corporation - Applicants: Santec Corporation - Inventors: Changho CHONG; Masayuki OKANO - Web page: https://patentgrep.com/patent/US20210278538A1 ## CPC - G01S 17/58: Velocity or trajectory determination systems; Sense-of-movement determination systems - G01B 9/02003: using beat frequencies - G01B 9/02004: using frequency scans - G01B 9/02045: {using the Doppler effect} - G01B 9/0207: {Error reduction by correction of the measurement signal based on independently determined error sources, e.g. using a reference interferometer} - G01S 7/4815: {using multiple transmitters} - G01S 7/4817: {relating to scanning} - G01S 7/4911: Transmitters - 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 17/42: Simultaneous measurement of distance and other co-ordinates (indirect measurement G01S17/46) - G06F 17/142: {Fast Fourier transforms, e.g. using a Cooley-Tukey type algorithm} - G01B 2290/60: Reference interferometer, i.e. additional interferometer not interacting with object - 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 - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract System and methods for Light Detecting and Ranging (LIDAR) are disclosed. The LIDAR system includes a light source that is configured project a beam at various wavelengths toward a wavelength dispersive element. The wavelength dispersive element is configured to receive the beam and direct at least a portion of the beam into a field of view (FOV) at an angle dependent on frequency. The system also includes a detector that is positioned to receive portions of the beam reflected from an object within the FOV and a processor that is configured to control the light source and determine a velocity of the object. ## Claims ### Claim 1 A light detecting and ranging (LIDAR) system, the system comprising: a light source configured to generate a beam having discrete frequencies at different times; a wavelength dispersive element positioned to receive at least a portion of the beam and configured to sweep the beam over a range of angles in a field of view (FOV), wherein each discrete frequency of the beam corresponds to a different angle in the FOV; a detector positioned to receive portions of the beam that are reflected from an object within the FOV and configured to generate an object signal based on the received portions of the beam; and a processor communicably coupled to the detector, the processor configured to: cause the beam to sweep from a first frequency at a first time to a second frequency over a ramp up time period; cause the beam to sweep from the second frequency back to the first frequency over a ramp down time period; and determine a velocity of the object based on characteristics of the beam. ### Claim 2 (depends on 1) The system of claim 1, wherein to determine the velocity of the object, the processor is further configured to: identify a first portion of the object signal that corresponds to the object detected during the ramp up time period; and identify a second portion of the object signal that corresponds to the object detected during the ramp down time period. ### Claim 3 (depends on 2) The system of claim 2, wherein to determine the velocity of the object, the processor is further configured to: calculate a first beat frequency for the first portion of the object signal; and calculate a second beat frequency for the second portion of the object signal. ### Claim 4 (depends on 3) The system of claim 3, wherein the first beat frequency is calculated using the first portion of the object signal and a first portion of the generated beam that corresponds to the first object signal, and the second beat frequency is calculated using the second portion of the object signal and a second portion of the generated beam corresponding to the second object signal. ### Claim 5 (depends on 3) The system of claim 3, wherein the processor is further configured to determine a distance of the object from the LIDAR system using the first beat frequency and the second beat frequency. ### Claim 6 (depends on 1) The system of claim 1, further comprising: an interferometer; and a beam splitting device positioned between the light source and the wavelength dispersive element, the beam splitting device configured to receive the beam generated by the light source and split the beam into an object beam that is directed toward the wavelength dispersive element and a reference beam that is directed toward the interferometer; wherein the interferometer is configured to detect frequencies of the reference beam. ### Claim 7 (depends on 1) The system of claim 1, wherein the ramp up time period and the ramp down time period correspond to a first frame, wherein the processor is further configured to cause the beam to sweep from the first frequency at a second time to the second frequency over a second ramp up time period and cause the beam to sweep from the second frequency back to the first frequency over a second ramp down time period, and wherein the second time, the second ramp up time period, and the second ramp down time period correspond to a second frame. ### Claim 8 (depends on 7) The system of claim 7, the processor further configured to: determine a first distance and a first angle of the object relative to LIDAR system during the first frame; determine a second distance and a second angle of the object relative to the LIDAR system during the second frame; and determine a velocity vector of the object relative to the LIDAR system using the first distance, the second distance, the first angle, and the second angle. ### Claim 9 (depends on 7) The system of claim 7, wherein to determine the second distance of the object, the processor is further configured to: predict the second distance of the object relative to the LIDAR system using the first distance and the velocity of the object; generate a filter based on the predicted second distance; and filter received signals from the object in the second frame using the filter. ### Claim 10 (depends on 7) The system of claim 7, the processor further configured to determine a velocity vector of the object relative to an environment external to the LIDAR system using the velocity vector of the object relative to the LIDAR system and a velocity vector of the LIDAR system relative to the environment external to the LIDAR system. ### Claim 11 A system, comprising: a light source configured to generate a beam having discrete frequencies at different times; a wavelength dispersive element positioned to receive at least a portion of the beam and configured to sweep the beam over a range of angles in a field of view (FOV), wherein each discrete frequency of the beam corresponds to a different angle in the FOV; a detector positioned to receive portions of the beam that are reflected from an object within the FOV and configured to generate an object signal based on the received portions of the beam; and a processor communicably coupled to the detector configured to: cause the beam to sweep from a first frequency at a first time to a second frequency over a time period; and determine a velocity of the object based on the portions of the beam received by the detector. ### Claim 12 (depends on 11) The system of claim 11, wherein to determine the velocity, the processor is further configured to: determine a phase of a first portion of an object signal, the object signal based on the portions of the beam received by the detector; and determine a phase of a second portion of the object signal. ### Claim 13 (depends on 12) The system of claim 12, wherein the phase of the first portion is determined by performing a fast Fourier transform (FFT) on the first portion of the object signal and the phase of the second portion is determined by performing a FFT on the second portion of the object signal. ### Claim 14 (depends on 13) The system of claim 13, the processor further configured to determine a distance of the object from system, wherein the distance is determined based on the amplitude of the FFT of the first portion of the object signal and the amplitude of the FFT of the second portion of the object signal. ### Claim 15 (depends on 12) The system of claim 12, wherein to determine the velocity, the processor is further configured to: determine a time difference between the first portion and the second portion; estimate a wavelength of the beam; and determine the velocity using the phase of the first portion, the phase of the second portion, the time difference, and the wavelength. ### Claim 16 (depends on 11) The system of claim 11, wherein the time period corresponds to a first frame, and wherein the processor is further configured to cause the beam to sweep from the first frequency at a second time to the second frequency continuously over a second time period, wherein the second time period corresponds to a second frame, and wherein to determine the velocity, the processor is further configured to: determine a phase of a first object signal that corresponds to the object in the first frame; determine a phase of a second object signal that corresponds to the object in the second frame; and determine the velocity using the phase of the first portion, the phase of the second portion, and a wavelength corresponding to the first object signal. ### Claim 17 A method of determining a velocity of an object within a field of view (FOV) of a sensing system, the method comprising: controlling, via a processor, a light source to project a beam that is swept from a first frequency to a last frequency starting at a first time over a first time period; projecting the beam toward a wavelength dispersive element; directing the beam into a FOV at angles depending on frequency; directing portions of the beam reflected from an object in the FOV to a detector; generating an object signal based on received portions of the beam from the object in the FOV; and determining, via the processor, a velocity of the object based on the object signal. ### Claim 18 (depends on 17) The method of claim 17, wherein the velocity of the object is determined using a phase of a first portion of the object signal and a phase of a second phase of the object signal. ### Claim 19 (depends on 17) The method of claim 17, further comprising: controlling, via the processor, the light source to sweep continuously the beam from the last frequency back to the first frequency after the first time period over a second time period; and wherein determining the velocity of the object is based on an object signal corresponding to the object detected during the first time period and an object signal corresponding to the object detected during the second time period. ### Claim 20 (depends on 18) The method of claim 18, further comprising: controlling, via the processor, the light source to project a beam that is swept continuously from the first frequency to the last frequency at a second time during a second time period, wherein the second time is after the first time period; wherein determining the velocity of the object is based on an object signal corresponding to the object detected during the first time period and an object signal corresponding to the object detected during the second time period.