A frequency modulated continuous wave lidar system

Abstract

The application provides a frequency-modulated continuous wave laser radar system and relates to the technical field of laser radar.The frequency-modulated continuous wave laser radar system comprises a laser, an arbitrary waveform generator, an upper computer, a collection card, a lens, a first optical beam splitter, a linearity correction unit and a detection unit.The linearity correction unit comprises a second optical beam splitter, a delay line, a first coupler and a first balanced detector.The detection unit comprises a third optical beam splitter, a coaxial transceiving grating, a second coupler and a second balanced detector.The frequency-modulated continuous wave laser radar system improves the signal-to-noise ratio and the energy efficiency of the edge field of view, uses the coaxial transceiving grating to replace the circulator, eliminates the near-distance detection blind area of the radar system caused by the internal reflection of the circulator, integrates the linearity correction unit, performs real-time correction or monitoring on the frequency modulation of the laser, enhances the stability of the radar system, and does not need to build any additional optical circuit.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of laser radar, more particularly, to a frequency-modulated continuous wave laser radar system. BACKGROUND

[0002] Laser radar is the core technology for automatic driving vehicles and unmanned vehicles to obtain three-dimensional spatial information and realize spatial remote sensing. In order to meet the needs of automatic driving, laser radar needs to have precise beam control capability and high reliability. The current common mechanical and micro-electromechanical system laser radars are prone to mechanical structure wear and aging due to the presence of movable mechanical parts, so they cannot meet the needs of application scenarios such as automatic driving. Therefore, the all-solid-state laser radar without any mechanical structure is a solution for automatic driving applications. At present, silicon-based optical phased array laser radars have been studied internationally, but the optical phased array needs to expand the antenna scale to improve the efficiency of the radar, but the complexity of the control system brought by the large-scale antenna is unacceptable. In addition, the solid-state laser radar scheme combined with a vertical cavity surface emitting laser array and a single photon detector array has a large complexity of optical alignment because the two arrays are independent chips and the whole radar system works in an off-axis state. Moreover, the single photon detector and the vertical cavity surface emitting laser can only be used for direct time-of-flight laser radar, and cannot be used for frequency-modulated continuous wave laser radar.

[0003] The frequency-modulated continuous wave laser radar system is widely used in high-precision ranging and three-dimensional imaging, and has high anti-interference performance and long detection distance. However, due to the linearity of the light source sweep and the complexity of the optical detection link, the integration of the system faces great challenges. The traditional frequency-modulated continuous wave laser radar usually pre-corrects the linear sweep of the laser before use, but in a complex working environment, the linearity of the linear sweep of the laser may decrease after a long time of work, resulting in a decrease in system reliability, and the linearity correction loop further increases the complexity of the system. On the other hand, the frequency-modulated continuous wave laser radar system usually uses a circulator to build a coaxial optical link, but the circulator has low integration and high cost, and the crosstalk in the circulator often introduces undesirable noise to the system.

[0004] Currently, lens-assisted focal plane optical switch array lidar also attracts the research of some teams, by switching the optical antenna at different positions on the focal plane of the lens, the beam steering is realized by the mapping relationship from the focal plane of the lens to the far field. However, due to the optical reflection in the integrated device, the crosstalk between the transmission link and the receiving link is large, and the signal noise of the focal plane optical switch array is large. The discrete switch array works in the off-axis state, and the transmission array and the receiving array are placed on the focal planes of two lenses. Since two lenses are used, the antennas opened by the transmission array and the antennas opened by the receiving array will be located at different positions, and their corresponding relationship depends on the relative positions of the two optical arrays and the position of the measured object, so a complex optical alignment is needed and it is not easy to operate. In addition, the transmission and reception efficiency of the antennas located at the edge of the field of view is low, which affects the detection ability of the edge field of view. The existing on-chip optical antenna is usually realized by waveguide grating, but the beam of the waveguide grating is usually vertically upward. In this arrangement, the light emitted by the antenna at the center passes through the center of the lens and is directed to the center of the field of view, with the highest energy efficiency. The antennas at the edge of the array correspond to the edge of the radar field of view. Since the beam of the antenna is vertically upward and far away from the center of the lens, the energy efficiency at the edge of the field of view is low.

[0005] Therefore, there is an urgent need for a new frequency-modulated continuous wave lidar system to effectively solve the problems of crosstalk between the transmission link and the receiving link, low energy efficiency at the edge of the field of view, and eliminate the near-range detection blind area of the radar system caused by the internal reflection of the circulator, so as to improve the signal-to-noise ratio and integration and improve the energy efficiency. SUMMARY

[0006] In view of the problems in the background art, the present application provides a frequency-modulated continuous wave lidar system to solve the defects of the prior art frequency-modulated continuous wave lidar system.

[0007] The technical scheme for solving the above technical problems is as follows:

[0008] A frequency-modulated continuous wave lidar system, comprising:

[0009] A laser, an arbitrary waveform generator, an upper computer, a collection card, a lens, a first optical beam splitter, a linearity correction unit and a detection unit;

[0010] The linearity correction unit comprises a second optical beam splitter, a delay line, a first coupler and a first balanced detector;

[0011] The detection unit comprises a third optical beam splitter, a coaxial transceiver grating, a second coupler and a second balanced detector;

[0012] The coaxial transceiving grating comprises a plurality of groups of transceiving grating antennas, each group of transceiving grating antennas comprising a transmitting grating antenna and a receiving grating antenna, the transmitting grating antenna and the receiving grating antenna being closely arranged coaxially, the transmitting grating antenna and the receiving grating antenna being located on a focal plane of a same lens, there being an integrated isolator between the transmitting grating antenna and the receiving grating antenna, the transmitting grating antenna and the receiving grating antenna adopting a special-shaped grating structure, so that the diffraction directions of the transmitting grating antenna and the receiving grating antenna at different positions on the focal plane are all directed to the center of the same lens, and in the special-shaped grating structure, the grating teeth of the transmitting grating antenna and the receiving grating antenna at different positions on the focal plane form an inclined angle α with a horizontal direction, 0°<α<90°, the horizontal direction being a direction perpendicular to the input light.

[0013] Preferably, the relationship between the inclined angle α and the transverse deflection angle θ is as follows:

[0014] wherein n eff is the effective refractive index of the waveguide, λ is the wavelength of the transmitted light, and Λ is the grating period.

[0015] Preferably, the first optical beam splitter divides the light beam output by the laser into two parts, one part being transmitted to the third optical beam splitter in the detection unit as probe light, and the other part being transmitted to the second optical beam splitter in the linearity correction unit as correction light.

[0016] The second optical beam splitter outputs one part of light as light with a light power of 90% to the delay line, and outputs another part of light as light with a light power of 10% to the first coupler. The two parts of light output by the second optical beam splitter are mixed in the first coupler. The two output ends of the first coupler are connected to the two input ends of the first balanced detector. The photoelectric conversion is completed in the first balanced detector to output a correction beat frequency signal.

[0017] The third optical beam splitter outputs 95% of light as probe light to the coaxial transceiving grating, and outputs 5% of light as local oscillator light directly to the second coupler. The probe light becomes signal light after carrying detection information through reflection by an external object. The signal light is transmitted to the second coupler by the receiving grating antenna. The signal light and the local oscillator light are mixed in the second coupler. The two output ends of the second coupler are connected to the two input ends of the second balanced detector. The photoelectric conversion is completed in the second balanced detector to output a detection beat frequency signal.

[0018] Preferably, the frequency-modulated continuous wave laser radar system realizes real-time correction by the following steps:

[0019] Step 1, the host computer controls the arbitrary waveform generator to generate a synchronization signal and a sweep signal with a period of T, and the synchronization signal and the sweep signal are the same period and the same phase;

[0020] Step 2, the arbitrary waveform generator applies the sweep signal to the laser, and transmits the synchronization signal to the acquisition card;

[0021] Step 3, the laser generates modulated light, the modulation bandwidth is B, the modulation period is T, and the modulation slope is The modulated light is divided into correction light and probe light in the first optical beam splitter;

[0022] Step 4, the correction light is divided into two parts by the second optical beam splitter and transmitted to the delay line and the first coupler respectively, and the light output by the delay line generates a delay After entering the first coupler, wherein L is the physical length of the delay line, n is the refractive index of the delay line, and c is the speed of light, the first coupler realizes mixing and generates a correction beat signal in the first balanced detector, and the generated beat frequency is f1=γτ1; the probe light is divided into two parts by the third optical beam splitter, one part enters the coaxial transceiver grating and emits into the external space to obtain the signal light entering the second coupler, and the other part directly enters the second coupler as the local oscillator light, and the delay between the signal light and the local oscillator light is Wherein R is the detection distance, the signal light and the local oscillator light complete mixing in the second coupler, and generate a probe beat signal in the second balanced detector, and the generated beat frequency is f2=γτ2;

[0023] Step 5, the correction beat signal and the probe beat signal are collected by the acquisition card to the host computer;

[0024] Step 6, the host computer cuts the correction beat signal and the probe beat signal according to the synchronization signal, to ensure that the correction beat signal and the probe beat signal of a single period are processed;

[0025] Step 7, the host computer processes the correction beat signal according to the linearity correction algorithm, and updates the sweep voltage waveform.

[0026] The beneficial effects of the present application are:

[0027] (1) The transmitting grating antenna and the receiving grating antenna are closely arranged to form a coaxial, the transmitting grating antenna and the receiving grating antenna are located on the focal plane of the same lens, the light beam emitted by the transmitting grating antenna reaches the target object, and the reflected light basically returns to the adjacent receiving grating antenna for receiving, thereby avoiding complex beam alignment and simple operation;

[0028] (2) By adopting the special-shaped grating structure, the diffraction directions of the transmitting grating antenna and the receiving grating antenna at each part of the focal plane are all directed to the center of the same lens, so that the energy efficiency of the edge of the field of view is improved, which is caused by the vertical upward emission of the antenna beam;

[0029] (3) The transverse scanning angle control is easily realized through the relationship between the inclination angle alpha and the transverse deflection angle theta;

[0030] (4) The linearity correction unit is integrated on the chip, so that the frequency modulation linearity of the laser can be corrected and monitored in real time, and the chip-level real-time linearity correction improves the stability of the long-time work of the laser radar system;

[0031] (5) The waveguide grating is used to complete the transmitting and receiving process of the probe beam, so that the reflection signal peak of the device will not be generated at the low frequency of the beat signal, and the near-detection blind area of the laser radar system is eliminated. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to make the present application easier to understand, the present application will be described in more detail by referring to the specific embodiments shown in the accompanying drawings. These drawings only depict typical embodiments of the present application and should not be considered as limiting the scope of protection of the present application.

[0033] Figure 1 is a structure schematic diagram of a frequency-modulated continuous wave laser radar system provided by an embodiment of the present application;

[0034] Figure 2 is a structure schematic diagram of a set of transmitting and receiving grating antennas of a coaxial transmitting and receiving grating provided by an embodiment of the present application;

[0035] Figure 3 is a coaxial working mode schematic diagram provided by an embodiment of the present application;

[0036] Figure 4 is a special-shaped grating schematic diagram provided by an embodiment of the present application;

[0037] Figure 5 is a relationship diagram of the inclination angle alpha and the transverse deflection angle theta of the special-shaped grating provided by an embodiment of the present application.

[0038] Reference signs:

[0039] 301-transmitting grating antenna, 302-isolator, 303-receiving grating antenna. DETAILED DESCRIPTION

[0040] Embodiments of the present application will be described below with reference to the accompanying drawings so as to be more clearly understood by those skilled in the art, and to enable the present application to be carried out into practice. The following embodiments are presented by way of illustration and are not intended to be limiting of the present application. The following embodiments and features of the embodiments described below can be combined with each other unless otherwise contradicted, wherein the same components are denoted by the same reference numerals. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative efforts are within the scope of the present application.

[0041] The present application provides a frequency-modulated continuous wave laser radar system. Please refer to Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 , Figure 1 is a structural schematic diagram of a frequency-modulated continuous wave laser radar system provided by an embodiment of the present application; Figure 2 is a structural schematic diagram of a group of transceiving grating antennas of a coaxial transceiving grating provided by an embodiment of the present application; Figure 3 is a coaxial working mode schematic diagram provided by an embodiment of the present application; Figure 4 is a special-shaped grating schematic diagram provided by an embodiment of the present application; Figure 5 is a graph of the relationship between the tilt angle a and the lateral deflection angle θ of the special-shaped grating provided by an embodiment of the present application.

[0042] Please refer to Figure 1 , in an embodiment of the present application, the frequency-modulated continuous wave laser radar system comprises a laser, an arbitrary waveform generator, an upper computer, a collection card, a lens, an optical beam splitter 1, a linearity correction unit and a detection unit; the linearity correction unit comprises an optical beam splitter 2, a delay line, a coupler and a balanced detector; the detection unit comprises an optical beam splitter 3, a coaxial transceiving grating, a coupler and a balanced detector. The optical beam splitter 1, the detection unit and the linearity correction unit are integrated on the same laser radar chip.

[0043] The laser radar chip can complete two functions of real-time linearity correction and frequency-modulated beam transceiving in the frequency-modulated continuous wave laser radar system. The functions of each module of the chip are as follows:

[0044] The optical beam splitter 1: divides the beam output by the laser into two parts, one part with an optical power of 80% and the other part with an optical power of 20%, wherein the part with an optical power of 80% is transmitted to the detection unit, and the part with an optical power of 20% is transmitted to the linearity correction unit.

[0045] The linear correction unit: the optical beam transmitted to the linear correction unit is divided into two parts by the optical beam splitter 2: a part with 90% of the optical power and a part with 10% of the optical power, wherein the part with 90% of the optical power is transmitted to an optical waveguide delay line with a certain length, and the part with 10% of the optical power is directly transmitted to the coupler; the light output by the delay line also enters the coupler and is mixed with the light directly transmitted to the coupler in the coupler to generate a correction beat signal; the output of the coupler is connected to the balanced detector; the light is optoelectronically converted in the balanced detector, and the correction beat signal is output.

[0046] The detection unit: the light is divided into two parts by the optical beam splitter 3, wherein 95% of the light is transmitted to the coaxial transceiver grating as the detection light, and 5% of the light is directly transmitted to the coupler as the local oscillator light; the detection light becomes signal light after carrying the detection information after being reflected by the external object; the signal light and the local oscillator light are mixed in the coupler to generate a detection beat signal; the detection beat signal is optoelectronically converted in the balanced detector and output; the two input ends of the coupler in the detection unit are respectively connected to the coaxial transceiver grating and the output end of the optical beam splitter 3; and the two output ends of the coupler are connected to the two input ends of the balanced detector.

[0047] In the embodiment of the application, the method of iterative learning is used to correct the nonlinearity; after the correction beat signal and the synchronization signal are collected by the acquisition card, the process is carried out in the host computer. First, the single period of the correction beat signal is extracted according to the synchronization signal; the nonlinearity of the sweep frequency is restored using Hilbert transform; the ideal sweep frequency waveform is fitted according to the restored actual sweep frequency waveform; the difference between the ideal sweep frequency waveform and the actual sweep frequency waveform at each sampling point is calculated, which is called residual error; and finally, the sweep frequency waveform is updated using the linearity correction algorithm.

[0048] The real-time correction process specifically adopts the following steps:

[0049] Step 1: the host computer controls the arbitrary waveform generator to generate a synchronization signal and a sweep signal with a period of T, and the synchronization signal and the sweep signal are the same period and phase;

[0050] Step 2: the arbitrary waveform generator applies the sweep signal to the laser and transmits the synchronization signal to the acquisition card;

[0051] Step 3: the laser generates modulated light, the modulation bandwidth is B, the modulation period is T, and the modulation slope γ is The modulated light is divided into correction light and detection light in the optical beam splitter 1, the correction light is transmitted to the optical beam splitter 2, and the detection light is transmitted to the optical beam splitter 3;

[0052] Step 4: the correction light is divided into two parts by the optical beam splitter 2, one part of the light passes through the delay line to generate a delay Wherein L is the physical length of the delay line, n is the refractive index of the delay line, c is the speed of light, the other part of the light directly enters the coupler, and the two parts of the light produce a correction beat frequency signal in the balanced detector after passing through the coupler, and the generated beat frequency f1 is f1=gamma tau1; the probe light is divided into two parts by the optical beam splitter 3, one part enters the coaxial transceiver grating to emit into the external space to obtain signal light, and the other part directly enters the coupler as the local oscillation light, and the signal light and the local oscillation light produce a delay Wherein R is the detection distance, the signal light and the local oscillation light are mixed in the coupler, the detection beat frequency signal is generated in the balanced detector, and the generated beat frequency f2 is f2=gamma tau2.

[0053] Step 5, the correction beat frequency signal and the detection beat frequency signal are collected by the acquisition card to the upper computer;

[0054] Step 6, the upper computer cuts the correction beat frequency signal and the detection beat frequency signal according to the synchronization signal, so that the correction beat frequency signal and the detection beat frequency signal of a single period are processed;

[0055] Step 7, the upper computer processes the correction beat frequency signal according to the linearity correction algorithm, and updates the sweep voltage waveform.

[0056] The linear correction unit is integrated on the chip, so that the frequency modulation linearity of the laser can be corrected and monitored in real time, and the chip-level real-time linearity correction improves the stability of the long-time working of the laser radar system.

[0057] The embodiment of the application also provides a coaxial transceiving grating, which comprises a plurality of groups of transceiving grating antennas, each group of transceiving grating antennas comprising a transmitting grating antenna and a receiving grating antenna.

[0058] Figure 2 is a structural schematic view of a group of transceiving grating antennas of the coaxial transceiving grating provided by the embodiment of the application, Figure 2 In the figure, the transmitting grating antenna 301 and the receiving grating antenna 303 are closely arranged, and an integrated isolator 302 is arranged between the transmitting grating antenna 301 and the receiving grating antenna 303, which is used for isolating the transceiving optical link and avoiding crosstalk.

[0059] Figure 3The application provides a coaxial working mode schematic diagram; the laser radar chip of the application works under a focal plane of a lens; a transmitting grating antenna 301 and a receiving grating antenna 303 in a group of transmitting and receiving grating antennas are closely arranged, and the interval is within several microns; the light beam emitted by the transmitting grating antenna 301 reaches a target object, and the reflected light basically returns to the adjacent receiving grating antenna 303 to be received. A column lens with a proper aperture is arranged at the upper focal length position of the group of transmitting and receiving grating antennas; the corresponding transmitting and receiving grating antennas are switched to realize the emission of the light beam and the reception of the reflected light. The closely arranged transmitting grating antenna 301 and the receiving grating antenna 303 are basically located at the same position of the focal plane, and form a coaxial laser radar system, so that the complex beam alignment is avoided; the group of transmitting and receiving grating antennas work on the focal plane of the same lens; due to the interval of the integrated transmitting grating antenna 301 and the receiving grating antenna 303, the interval is within several microns, so that the interval of the transmitting grating antenna 301 and the receiving grating antenna 303 is smaller than the light spot converged on the focal plane, and the transmitting grating antenna 301 and the receiving grating antenna 303 can be regarded as being located at the same position.

[0060] The existing grating is 90° between the input light direction and the grating tooth direction, different input wavelengths are used to realize different longitudinal deflection, and the grating tooth does not have an inclination angle with the horizontal direction, so that the grating tooth does not have a transverse component and cannot set a transverse deflection angle; the light beam of the waveguide grating is usually vertically emitted upward. In this arrangement mode, the light emitted by the antenna at the center passes through the center of the lens and points to the center of the field of view, and the energy efficiency is the highest, but the antennas at the edges of the array correspond to the edges of the radar field of view, and the light beams of the antennas are vertically emitted upward, far away from the center of the lens, so that the energy efficiency at the edges of the field of view is low. The application adopts a special-shaped grating structure, Figure 4 is a special-shaped grating schematic diagram provided by the application; Figure 5 is a relationship diagram of the inclination angle α and the transverse deflection angle θ of the special-shaped grating provided by the application.

[0061] Referring to Figure 4 , the waveguide grating is arranged along the y-axis, and the input light is transmitted along the vertical direction of the y-axis. is the transmission vector of the input light, α is the included angle between the grating tooth and the x-axis horizontal direction, that is, the inclination angle, and Λ is the grating period, is the grating vector, is the transmission vector of the m-order diffracted light (herein, m=1), is the longitudinal deflection angle, and θ is the transverse deflection angle.

[0062] According to the grating equation:

[0063]

[0064] wherein The projection of the transmission vector of the mth order diffracted light in the xy plane can be orthogonally decomposed into an x-axis direction component and a y-axis direction component;Wherein, n eff is the effective refractive index of the waveguide, lambda is the wavelength of the transmitted light, and Lambda is the grating period:

[0065]

[0066] The transverse deflection angle theta of the diffracted light beam satisfies

[0067]

[0068] Let m=1, and the relationship between the tilt angle alpha and the transverse deflection angle theta is obtained by simultaneously solving equations (1)-(3):

[0069]

[0070] Referring to Figure 5 , a graph of the relationship between the tilt angle alpha and the transverse deflection angle theta of the special-shaped grating is shown, the transverse deflection angle is adjusted by changing the size of the tilt angle, and according to the relationship between the tilt angle alpha and the transverse deflection angle theta, the transverse scanning angle control can be easily realized.

[0071] In order to improve the integration of the laser radar system, the coaxial transceiver grating is used instead of the circulator, which can not only complete the integration on the chip, but also eliminate the near detection blind area of the radar system caused by internal reflection of the circulator, and the linearity correction system is integrated to improve the ability of the radar system to cope with complex working environment, and is used for additional optical circuit.

[0072] In the present application, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between each embodiment can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the related parts can be referred to the method part.

[0073] The above-described embodiments are only the preferred specific embodiments of the present application, and the phrases "in an embodiment", "in another embodiment", "in still another embodiment" or "in other embodiments" in the specification all refer to one or more of the same or different embodiments according to the present disclosure. The usual changes and replacements made by those skilled in the art within the scope of the technical scheme of the present application should be included in the protection scope of the present application.

Claims

1. A frequency modulated continuous wave lidar system, characterized by, The application relates to a frequency-modulated continuous wave laser radar system. The application relates to a frequency-modulated continuous wave laser radar system. The application relates to a frequency-modulated continuous wave laser radar system. The application relates to a frequency-modulated continuous wave laser radar system. The application relates to a frequency-modulated continuous wave laser radar system.

2. The frequency modulated continuous wave lidar system of claim 1, wherein, The application relates to a frequency-modulated continuous wave laser radar system. where n eff is the effective refractive index of the waveguide, λ is the wavelength of the light being transmitted, and Λ is the grating period.

3. The frequency modulated continuous wave lidar system of claim 2, wherein, The application relates to a frequency-modulated continuous wave laser radar system. The application relates to a frequency-modulated continuous wave laser radar system. The application relates to a frequency-modulated continuous wave laser radar system.

4. The frequency-modulated continuous wave lidar system of claim 3, wherein, The application relates to a frequency-modulated continuous wave laser radar system. The application relates to a frequency-modulated continuous wave laser radar system. The application relates to a frequency-modulated continuous wave laser radar system. The application relates to a frequency-modulated continuous wave laser radar system. The application relates to a frequency-modulated continuous wave laser radar system. The application relates to a frequency-modulated continuous wave laser radar system. The application relates to a frequency-modulated continuous wave laser radar system. The application relates to a frequency-modulated continuous wave laser radar system. The application relates to a frequency-modulated continuous wave laser radar system. The application relates to a frequency-modulated continuous wave laser radar system. 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The application relates to a frequency-modulated continuous wave laser radar system. The application relates to a frequency-modulated continuous wave laser radar system. The application relates to a frequency-modulated continuous wave laser radar system. The application relates to a frequency-modulated continuous wave laser radar system. The application relates to a frequency-modulated continuous wave laser radar system. The application relates to a frequency-modulated continuous wave laser radar system. The application relates to a frequency-modulated continuous wave laser radar system. The application relates to a frequency-modulated continuous wave laser radar system. The application relates to a frequency-modulated continuous wave laser radar system. The application relates to a frequency-modulated continuous wave laser radar system. The application relates to a frequency-modulated continuous wave laser radar system. The application relates to a frequency-modulated continuous wave laser radar system. The application relates to a frequency-modulated continuous wave laser radar system. The application relates to a frequency-modulated continuous wave laser radar system. The application relates to a frequency-modulated continuous wave laser radar system. The application relates to a frequency-modulated continuous wave laser radar system. The application relates to a frequency-modulated continuous wave laser radar system. The application relates to Step 3, the laser generates modulated light, the modulation bandwidth is B, the modulation period is T, and the modulation slope is The modulated light is divided into correction light and detection light in the first optical beam splitter. Step 4, the correction light is transmitted to the delay line and the first coupler by the second optical beam splitter, and the light output by the delay line generates a delay The first coupler realizes mixing to generate a correction beat signal in the first balanced detector, and the generated beat frequency is f1=γτ1; the probe light is divided into two parts by the third optical beam splitter, one part enters the coaxial transceiver grating to emit into the external space to obtain the signal light entering the second coupler, and the other part directly enters the second coupler as the local oscillator light, and the delay generated by the signal light and the local oscillator light is Wherein R is the detection distance, the signal light and the local oscillator light complete mixing in the second coupler, a detection beat signal is generated in the second balanced detector, and the generated beat frequency is f2=γτ2; Step 5, the correction beat signal and the detection beat signal are collected by the acquisition card to the host computer; Step 6, the host computer cuts the correction beat signal and the detection beat signal according to the synchronization signal, ensuring that the correction beat signal and the detection beat signal of a single cycle are processed; Step 7, the host computer processes the correction beat signal according to the linearity correction algorithm, and updates the sweep voltage waveform.

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