CN117406233A - Linear frequency modulation continuous wave laser radar parallel ranging method based on electro-optical comb - Google Patents

Linear frequency modulation continuous wave laser radar parallel ranging method based on electro-optical comb Download PDF

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CN117406233A
CN117406233A CN202210805236.7A CN202210805236A CN117406233A CN 117406233 A CN117406233 A CN 117406233A CN 202210805236 A CN202210805236 A CN 202210805236A CN 117406233 A CN117406233 A CN 117406233A
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何必博
陈章渊
解晓鹏
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Peking University
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Peking University
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • 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
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
    • G01S17/06—Systems determining position data of a target
    • G01S17/08—Systems determining position data of a target for measuring distance only
    • G01S17/32—Systems determining position data of a target for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
    • G01S17/34—Systems determining position data of a target for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated 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
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • 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
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/88—Lidar systems specially adapted for specific applications
    • G01S17/93—Lidar systems specially adapted for specific applications for anti-collision purposes
    • G01S17/931—Lidar systems specially adapted for specific applications for anti-collision purposes of land vehicles

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Electromagnetism (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Optical Radar Systems And Details Thereof (AREA)

Abstract

The invention discloses a linear frequency modulation continuous wave laser radar parallel ranging method based on an electro-optical comb, which comprises the following steps: 1) Inputting the seed light source into a modulator for modulation to generate a single sideband signal; 2) Inputting single sideband signal light into an electro-optical comb generator to generate multi-wavelength FMCW laser; 3) Dividing the multi-wavelength FMCW laser into two paths for output; one path is used as local oscillation light to be input into a multichannel intensive optical wave multiplexing device; the other path is used as detection light to be output through the circulator; 4) The multi-wavelength FMCW laser output by the circulator is collimated and then is incident to the space grating to carry out light splitting in the first dimension direction; each beam after the light splitting realizes scanning in the second dimension direction through a control unit; 5) The reflected light of the object returns to the original path and is input to the multiplexing device when scanning, and the light output by each channel of the multiplexing device is received by a photoelectric detector and then input to the data processing unit; 6) The data processing unit draws a three-dimensional image of the object according to the input signal and marks the speed.

Description

Linear frequency modulation continuous wave laser radar parallel ranging method based on electro-optical comb
Technical Field
The invention relates to the field of microwave photonics, in particular to a linear frequency modulation continuous wave laser radar parallel ranging method and system based on an electro-optical comb. The invention is suitable for scene detection in the fields of unmanned driving, robots and the like, can rapidly realize large-scale scanning, and can complete imaging at a receiving end.
Background
With the development of the information age, unmanned automatic driving technology becomes a great demand, and the performance of the vehicle radar is determined by the vehicle radar as a key technology of unmanned automatic driving. The millimeter wave radar or the laser radar is arranged on the automobile, the millimeter wave radar or the laser radar emits signals, the obstacle reflects the radar signals and then is received by the automobile, and the distance and the speed of the obstacle at the front end of the automobile are detected through analysis of the reflected signals. The direction of radar emission signals is changed by combining a scanning device, and three-dimensional imaging is realized through point-by-point scanning. Compared with millimeter wave radar, the laser radar has the advantages of high resolution, good concealment, strong active interference resistance, good low-altitude detection performance, small volume and light weight. Based on ranging, lidars can be divided into two broad categories, time-of-flight (ToF) and chirped continuous wave (FMCW). The ToF technique uses the time of flight of light pulses between an obstacle and a lidar to measure distance, subject to stray light. Whereas the FMCW technique calculates the target distance by detecting the frequency difference between the local light and the return light by the mixing technique.
The FMCW laser radar utilizes the coherent detection technology to detect the frequency difference so as to realize the distance measurement, is not interfered by stray light, is more suitable for the vehicle-mounted laser radar, and becomes a research hot spot. The ranging resolution of the FMCW lidar depends on the sweep range, the greater the sweep range the higher the ranging resolution. Several efforts have been made in recent years to achieve three-dimensional imaging using FMCW lidar. For example, e.baumann et al utilized FMCW lidar to detect obstacle distances, combined with mode-locked optical frequency comb for frequency correction, to achieve three-dimensional physical imaging [ reference: baumann, et al, "Comb calibrated laser ranging for three-dimensional surface profiling with micrometer-level precision at a distance," Opt.express 22,24914-24928 (2014) ]. Along with the development of the optical frequency comb, a laser radar for realizing parallel ranging by combining the high-repetition-frequency optical frequency comb also becomes a research hot spot. The repetition frequency of the Kerr optical frequency comb depends on the micro-ring radius, and multi-wavelength FMCW laser with equal frequency interval distribution can be realized by using FMCW laser as seed light of the Kerr optical frequency comb. By combining the space grating to separate the light beams with various frequencies, multichannel parallel ranging can be realized [ reference: riemensberger, j., et al, "Massively parallel coherent laser ranging using a soliton microcomb," Nature 581,164-170 (2020) "]. However, the limited Yu Keer optical frequency comb is a harsh generation condition, the scheme can only realize the FMCW laser radar with a narrow frequency sweeping range, the ranging resolution is low, and the space for improving the frequency sweeping range and the ranging resolution exists.
Disclosure of Invention
In order to ensure parallel ranging and improve the sweep frequency range of the FMCW laser radar and improve the ranging resolution to meet the requirement of scanning imaging, the invention provides a linear frequency modulation continuous wave laser radar parallel ranging method and a system based on an electro-optical comb. The invention uses a continuous wave laser as a light source, and realizes single-sideband modulation by driving an electro-optic modulator through an Arbitrary Waveform Generator (AWG) to obtain single-wavelength FMCW laser. And then the single-wavelength FMCW laser is sent into an electro-optical comb generator consisting of a single intensity modulator and a plurality of phase modulators to obtain M (such as M=31) multi-wavelength FMCW lasers with equal frequency intervals, so that the distance between M points can be measured simultaneously, and the efficiency is M times that of the traditional single-wavelength FMCW laser radar.
The technical scheme adopted for solving the technical problems is as follows:
a linear frequency modulation continuous wave laser radar parallel ranging method based on an electro-optical comb comprises the following steps:
1) Inputting a seed light source into a modulator; driving the modulator to modulate the seed light source by using a waveform generator to generate a single sideband signal; the frequency range of the linear sweep frequency output by the waveform generator is B;
2) Inputting the single sideband signal light into an electro-optical comb generator to generate multi-wavelength FMCW laser with equal frequency intervals; wherein the FMCW laser is a chirped continuous wave laser;
3) Dividing the multi-wavelength FMCW laser into two paths for output; one path of the local oscillation light is input into the multichannel intensive optical wave multiplexing device; the other path is used as detection light to be output through the circulator;
4) The multi-wavelength FMCW laser output by the circulator is collimated by a collimator and converted into space light, and then the space light is incident to a space grating to split light in a first dimension direction; each beam after the space grating beam splitting realizes scanning in the second dimension direction through a beam scanning control unit; wherein the first dimension direction is perpendicular to the second dimension direction;
5) The reflected light of the object returns to the original path during scanning and then is input into the multi-channel dense light wave multiplexing device through the circulator; the multi-channel dense optical wave multiplexing device mixes the reflected light and the local oscillation light in the same frequency band in the same channel and outputs the mixed light, and the light output by each channel is respectively received by a corresponding photoelectric detector and then is input to the data processing unit;
6) And the data processing unit draws a three-dimensional image of the object according to the signals input by the photoelectric detector and marks speed information.
Further, the data processing unit comprises an spectrometer and a host; the spectrometer measures beat frequency signals according to signals input by the photoelectric detector and transmits the beat frequency signals to the host; and the host calculates distance information according to the beat frequency signals to realize imaging.
Further, the data processing unit processes according to the signals input by the photoelectric detector to obtain the distance of the objectSpeed->Wherein f u And f d Respectively representing a beat frequency value with higher frequency and a beat frequency value with lower frequency in the beat frequency signal, wherein T is the sweep frequency signal period of the waveform generator, and f c For detecting the optical frequency.
Further, the modulator is an electro-optic modulator; and the single sideband signal output by the electro-optic modulator is amplified by the EDFA and then input into the electro-optic comb generator to generate multi-wavelength laser with equal frequency intervals.
Further, the electro-optical comb generator comprises an intensity modulator and a plurality of cascaded phase modulators; the intensity modulator and the phase modulator are all of the same radio frequencyThe rate is f r Is driven by a radio frequency signal source; the intensity modulator is used for controlling the comb tooth flatness of the electro-optic optical frequency comb, and the phase modulator is used for spreading spectrum to obtain the multi-comb-tooth electro-optic optical frequency comb.
Furthermore, the electro-optical comb generator is a cascade modulator type electro-optical frequency comb generator, a cavity enhanced type electro-optical frequency comb generator of a Fabry-Perot cavity built-in phase modulator or an electro-optical comb generator based on integration on a thin film lithium niobate sheet.
Further, the multi-wavelength FMCW laser is amplified by the erbium-doped fiber amplifier and then split into two paths of outputs, wherein one path of the output serves as local oscillation light and the other path of the output serves as detection light.
Further, the wavelength of the seed light source is 1550nm; the line density of the space grating is greater than or equal to 1000 lines per mm, and the working wavelength is 1550nm.
Furthermore, the light beam scanning control unit is a micro-electromechanical system galvanometer or a fast steering mirror.
The linear frequency modulation continuous wave laser radar parallel ranging system based on the electro-optical comb is characterized by comprising a laser, a modulator, a waveform generator, an electro-optical comb generator, a multi-channel intensive optical wave multiplexing device, a circulator, a collimator, a space grating, a light beam scanning control unit and a data processing unit; wherein,
the laser is used for generating a seed light source;
the modulator is connected with the waveform generator and is used for modulating the input seed light source by using a driving signal of the waveform generator to generate a single sideband signal; the frequency range of the linear sweep frequency output by the waveform generator is B;
the electro-optical comb generator is used for generating multi-wavelength FMCW laser with equal frequency intervals according to the input single sideband signal light and dividing the multi-wavelength FMCW laser into two paths for output; one path of the local oscillation light is input into the multichannel intensive optical wave multiplexing device; the other path is used as detection light to be output through the circulator; wherein the FMCW laser is a chirped continuous wave laser;
the multi-wavelength FMCW laser output by the circulator is collimated by a collimator and converted into space light, and then the space light is incident to a space grating to split light in a first dimension direction; each beam after the space grating beam splitting realizes scanning in a second dimension direction through the beam scanning control unit; wherein the first dimension direction is perpendicular to the second dimension direction;
the reflected light of the object returns to the original path during scanning and then is input into the multi-channel dense light wave multiplexing device through the circulator; the multi-channel dense optical wave multiplexing device is used for mixing the reflected light and the local oscillation light in the same frequency band in the same channel and outputting the mixed light, and the light output by each channel is respectively received by a corresponding photoelectric detector and then is input to the data processing unit;
and the data processing unit draws a three-dimensional image of the object according to the signals input by the photoelectric detector and marks speed information.
The invention uses a continuous wave laser as a light source, and realizes single-sideband modulation to obtain single-wavelength FMCW laser by driving an electro-optic modulator through an Arbitrary Waveform Generator (AWG); compensating power loss by using an erbium-doped fiber amplifier (EDFA), and obtaining M multi-wavelength FMCW lasers with equal frequency intervals through an electro-optical comb generator consisting of a single intensity modulator and a plurality of phase modulators; the EDFA is used for compensating power loss, then the collimator is used for converting optical fiber light into space light, and the multi-wavelength light beam passes through the space grating with high dividing number to form M light beams which are irradiated on M points simultaneously; the returned light of M points is mixed with local M signal lights, and the distances of M points are obtained through intensive light wave multiplexing (DWDM) respectively. Scanning in another dimension may be achieved in combination with a microelectromechanical system (MEMS) galvanometer or a Fast Steering Mirror (FSM).
The beneficial effects of the invention are as follows:
the invention provides a parallel ranging FMCW laser radar realization method with high sweep frequency range and high measurement accuracy, which is suitable for application of vehicle-mounted laser radar and the like, realizes quick scanning and accurate ranging, and greatly improves the performance of the vehicle-mounted laser radar.
Drawings
FIG. 1 is a schematic diagram of a parallel ranging linear frequency modulation continuous wave laser radar system based on an electro-optic optical frequency comb;
FIG. 2 shows a single-sideband modulated single-wavelength FMCW laser, here exemplified by a sideband modulation frequency of 10 GHz;
FIG. 3 is a spectrum of a multi-wavelength laser generated after passing through an electro-optic optical frequency comb generator, here exemplified by a sideband modulation frequency of 10 GHz;
fig. 4 is an image of the method, here exemplified by a complete obstacle and a perforated obstacle at a distance of 20 cm.
Wherein, 1, a continuous wave laser, 2, an electro-optical modulator, 3, an arbitrary waveform generator, 4, an erbium-doped fiber amplifier, 5.M comb-tooth electro-optical frequency comb generator, 6, an erbium-doped fiber amplifier, the system comprises a light circulator, a collimator, a space grating, a light beam scanning control unit, an obstacle, a 12M channel dense light wave multiplexing device, an electric spectrometer and a host.
Detailed Description
The scheme of the invention is described in further detail below with reference to the accompanying drawings.
The scheme principle of the invention is shown in figure 1. The laser 1 with the wavelength of 1550nm is used as a seed light source, a single sideband signal is generated by an electro-optical modulator 2 driven by an Arbitrary Waveform Generator (AWG) 3, and the arbitrary waveform generator is connected with the electro-optical modulator through a K-head radio frequency cable and used for modulating and generating the single sideband signal. The frequency range of the linear sweep frequency outputted by the AWG is f 0 To (f) 0 +B), the sweep frequency range is B, and the sweep frequency range is 9.728GHz from 5GHz to 14.728 GHz. The output of the electro-optic modulator 2 is amplified by the EDFA to compensate for the loss, and the spectrum is shown in FIG. 2 when the frequency is swept to 10 GHz. The single sideband signal light then passes through an electro-optical comb generator 5 to generate multi-wavelength FMCW laser with equal frequency interval, the electro-optical comb generator is formed by connecting an intensity modulator and two phase modulators in series, and the three modulators are formed by connecting the same radio frequency with the frequency f r The signal output by the radio frequency signal source is divided into three paths after passing through the power divider, and the modulator is driven by the phase shifter and the radio frequency amplifier respectively. Wherein, the intensity modulator is used for controlling the comb tooth flatness of the electro-optic optical frequency comb, and the phase modulator is used for expanding spectrum to obtain multiple frequency bandsComb teeth electro-optic optical frequency comb. Thus the generation frequency is separated by f by the electro-optic comb generator 5 r 31-wavelength FMCW laser at=25 GHz. The multi-wavelength spectrum is shown in FIG. 3 when swept to 10 GHz. Note that the setting of the sweep range is not limited to the above-described parameter setting, and it is possible to ensure that no overlap occurs between the scanning beams, and thus the maximum sweep range is close to the electrooptic comb drive frequency of 25GHz. In addition, the above-mentioned electro-optical comb generator 5 belongs to a cascade modulator, the number of phase modulators is not limited to two, the main function of the phase modulators is to widen the spectrum, and more phase modulators can obtain a wider spectrum, so that more scanning points can be realized. The same effect can be achieved by using the cavity enhanced electro-optic optical frequency comb generator with the Fabry-Perot cavity built-in phase modulator. And both types of electro-optical comb generators may also use electro-optical comb generators based on integration on thin film lithium niobate sheets. In order to compensate the power loss of the electro-optical comb generator 5 and ensure that each comb tooth has enough power for detection, an erbium-doped optical fiber amplifier 6 is used for amplifying optical power, one path of amplified optical signals is used as local oscillation light, and the other path of amplified optical signals is connected with a collimator 8 through a circulator 7 for detection.
The multi-wavelength FMCW laser is converted into space light by a collimator 8 and then passes through a space grating 9 with a reticle density of 1000 lines per mm, and the working wavelength is 1550nm. When the laser is used, the incidence angle of the laser is controlled to be Littrow angle, and the transmittance of the light beam passing through the grating is highest. The multi-wavelength laser beam is split in the horizontal direction after passing through the space grating, and the beams are not overlapped after being transmitted for a certain distance, so that the distance information of different parts can be independently measured. Note that the denser the number of the grooves of the spatial grating, the stronger the spectroscopic effect, and the less likely the light beam overlap occurs, and a larger frequency sweep range can be allowed in accordance with the foregoing. The beam is scanned in the vertical direction by a beam scanning control unit 10, such as a mems galvanometer or a fast steering mirror. And combining the scanning of two dimensions to realize three-dimensional detection.
The single sideband signal light passes through the electro-optical comb generator 5 to generate light of M frequency bands; after the reflected light returns to the original path, the reflected light is mixed with local oscillation light through a circulator 7, and intensive light wave multiplexing is performed through M channels (channel interval 25 GHz)After the device 12, 31 different-frequency lights in the local oscillation light and the reflected light enter different channels, and the same-frequency light is in the same channel. The light of each channel is received by different photoelectric detectors to obtain beat frequency signals reflecting distance information, the beat frequency signals are measured by using an electric spectrometer and transmitted to a host computer, the host computer calculates the obstacle distance and speed information of corresponding points through a set FMCW ranging formula and records the obstacle distance and speed information in an array, and after the measurement is completed, three-dimensional images of the obstacle are drawn and the speed information is marked. The spectrometer and the host 13 process the beat frequency signals of the photoelectric detector to realize 31-channel parallel ranging. Distance D, velocity v and beat signal f u ，f d Relationship (where f u And f d Respectively representing higher and lower frequency beat values in the beat signal) is given by the following formula, where T is the period of the swept frequency signal of the AWG, f c For detecting the optical frequency.
Fig. 4 is an image of the method, here exemplified by a complete obstacle and a perforated obstacle at a distance of 20 cm.
The longitudinal resolution of the FMCW laser radar is c
There is Δr=1.54 cm in the above parameter settings.
The above embodiments are only for illustrating the technical solution of the present invention and not for limiting the same, and those skilled in the art may modify or substitute the technical solution of the present invention without departing from the spirit and scope of the present invention, and the protection scope of the present invention shall be defined by the claims.

Claims (10)

1. A linear frequency modulation continuous wave laser radar parallel ranging method based on an electro-optical comb comprises the following steps:
1) Inputting a seed light source into a modulator; driving the modulator to modulate the seed light source by using a waveform generator to generate a single sideband signal; the frequency range of the linear sweep frequency output by the waveform generator is B;
2) Inputting the single sideband signal light into an electro-optical comb generator to generate multi-wavelength FMCW laser with equal frequency intervals; wherein the FMCW laser is a chirped continuous wave laser;
3) Dividing the multi-wavelength FMCW laser into two paths for output; one path of the local oscillation light is input into the multichannel intensive optical wave multiplexing device; the other path is used as detection light to be output through the circulator;
4) The multi-wavelength FMCW laser output by the circulator is collimated by a collimator and converted into space light, and then the space light is incident to a space grating to split light in a first dimension direction; each beam after the space grating beam splitting realizes scanning in the second dimension direction through a beam scanning control unit; wherein the first dimension direction is perpendicular to the second dimension direction;
5) The reflected light of the object returns to the original path during scanning and then is input into the multi-channel dense light wave multiplexing device through the circulator; the multi-channel dense optical wave multiplexing device mixes the reflected light and the local oscillation light in the same frequency band in the same channel and outputs the mixed light, and the light output by each channel is respectively received by a corresponding photoelectric detector and then is input to the data processing unit;
6) And the data processing unit draws a three-dimensional image of the object according to the signals input by the photoelectric detector and marks speed information.
2. The method of claim 1, wherein the data processing unit comprises an spectrometer, a host; the spectrometer measures beat frequency signals according to signals input by the photoelectric detector and transmits the beat frequency signals to the host; and the host calculates distance information according to the beat frequency signals to realize imaging.
3. The method according to claim 2, wherein the data processing unit processes the distance of the object based on the signal input from the photodetectorSpeed->Wherein f u And f d Respectively representing a beat frequency value with higher frequency and a beat frequency value with lower frequency in the beat frequency signal, wherein T is the sweep frequency signal period of the waveform generator, and f c For detecting the optical frequency.
4. A method according to claim 1 or 2 or 3, wherein the modulator is an electro-optic modulator; and the single sideband signal output by the electro-optic modulator is amplified by the EDFA and then input into the electro-optic comb generator to generate multi-wavelength laser with equal frequency intervals.
5. A method according to claim 1 or 2 or 3, wherein the electro-optical comb generator comprises an intensity modulator and a plurality of cascaded phase modulators; the intensity modulator and the phase modulator are all of the same radio frequency f r Is driven by a radio frequency signal source; the intensity modulator is used for controlling the comb tooth flatness of the electro-optic optical frequency comb, and the phase modulator is used for spreading spectrum to obtain the multi-comb-tooth electro-optic optical frequency comb.
6. A method according to claim 1, 2 or 3, wherein the electro-optical comb generator is a cascade modulator type electro-optical comb generator, a fabry perot cavity-internal phase modulator type cavity-enhanced electro-optical comb generator or an electro-optical comb generator based on integration on a thin film lithium niobate sheet.
7. A method according to claim 1, 2 or 3, wherein the multi-wavelength FMCW laser is amplified by an erbium-doped fiber amplifier and split into two outputs, one of which is used as local oscillator light and the other as probe light.
8. The method of claim 1, wherein the seed light source has a wavelength of 1550nm; the line density of the space grating is greater than or equal to 1000 lines per mm, and the working wavelength is 1550nm.
9. The method of claim 1, wherein the beam scanning control unit is a mems galvanometer or a fast steering mirror.
10. The linear frequency modulation continuous wave laser radar parallel ranging system based on the electro-optical comb is characterized by comprising a laser, a modulator, a waveform generator, an electro-optical comb generator, a multi-channel intensive optical wave multiplexing device, a circulator, a collimator, a space grating, a light beam scanning control unit and a data processing unit; wherein,
the laser is used for generating a seed light source;
the modulator is connected with the waveform generator and is used for modulating the input seed light source by using a driving signal of the waveform generator to generate a single sideband signal; the frequency range of the linear sweep frequency output by the waveform generator is B;
the electro-optical comb generator is used for generating multi-wavelength FMCW laser with equal frequency intervals according to the input single sideband signal light and dividing the multi-wavelength FMCW laser into two paths for output; one path of the local oscillation light is input into the multichannel intensive optical wave multiplexing device; the other path is used as detection light to be output through the circulator; wherein the FMCW laser is a chirped continuous wave laser;
the multi-wavelength FMCW laser output by the circulator is collimated by a collimator and converted into space light, and then the space light is incident to a space grating to split light in a first dimension direction; each beam after the space grating beam splitting realizes scanning in a second dimension direction through the beam scanning control unit; wherein the first dimension direction is perpendicular to the second dimension direction;
the reflected light of the object returns to the original path during scanning and then is input into the multi-channel dense light wave multiplexing device through the circulator; the multi-channel dense optical wave multiplexing device is used for mixing the reflected light and the local oscillation light in the same frequency band in the same channel and outputting the mixed light, and the light output by each channel is respectively received by a corresponding photoelectric detector and then is input to the data processing unit;
and the data processing unit draws a three-dimensional image of the object according to the signals input by the photoelectric detector and marks speed information.
CN202210805236.7A 2022-07-08 2022-07-08 Linear frequency modulation continuous wave laser radar parallel ranging method based on electro-optical comb Pending CN117406233A (en)

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