Laser measurement method, laser radar and vehicle comprising laser radar

Abstract

The invention provides a laser measurement method and a laser radar, and relates to the field of laser radar measurement. The method comprises the following steps: generating a frequency sweeping light beam; splitting the sweep-frequency light beam into a signal light beam and a local oscillator light beam; emitting the signal light beam; receiving a reflected light beam generated by reflection of the signal light beam encountering an object; carrying out time delay or frequency shift on at least one of the signal light beam, the reflected light beam and the local oscillation light beam, and / or carrying out in-phase orthogonal coherent demodulation on the local oscillation light beam and the reflected light beam so as to obtain scalar values of beat frequency of a frequency raising stage and beat frequency of a frequency lowering stage; and detecting a beat frequency of an up-conversion phase and a beat frequency of a down-conversion phase between the local oscillator beam and the reflected beam to determine the speed of the object and / or the distance between the object and the lidar. According to the scheme, a measurement blind area can be avoided, and the measurement precision is improved.

Description

Technical Field

[0001] The present invention relates to the field of laser radar measurement, and in particular to a laser measurement method applied to laser radar, a laser radar and a vehicle including the laser radar. Background Art

[0002] LiDAR can accurately measure the position (distance and angle), motion state (speed, vibration and posture) and shape of the target object, detect, identify, distinguish and track the target object. LiDAR can be divided into pulsed LiDAR and continuous wave LiDAR according to the working mode. A typical continuous wave LiDAR emits a laser beam and uses a detector to receive the reflected beam of the target object from the nearby environment, thereby calculating information such as the distance and speed of the target object. However, the reflected beam used to calculate the distance and speed includes the optical Doppler frequency shift introduced by the movement of the target object. When the speed of the target object is fast, the frequency shift caused by the Doppler effect is greater than the frequency offset caused by the flight time of the reflected beam, which will lead to errors in the calculation of close-range information, resulting in measurement blind spots. Summary of the invention

[0003] In view of this, the present invention provides a laser measurement method applied to a laser radar, a laser radar and a vehicle including the radar, so as to solve the problem that when the laser radar in the prior art measures the target object, when the frequency shift caused by the Doppler effect is greater than the frequency offset caused by the flight time of the reflected light beam, it leads to errors in the calculation of close-range information, thereby causing a measurement blind spot.

[0004] In a first aspect, the present invention provides a laser measurement method applied to a laser radar, the method comprising: generating a swept frequency beam; splitting the swept frequency beam into a signal beam and a local oscillator beam; emitting the signal beam; receiving a reflected beam generated by the signal beam being reflected from an object; time delaying or frequency shifting at least one of the signal beam, the reflected beam and the local oscillator beam, and / or performing in-phase orthogonal coherent demodulation on the local oscillator beam and the reflected beam to obtain scalar values ​​of the beat frequency in the frequency up-conversion stage and the beat frequency in the frequency down-conversion stage between the local oscillator beam and the reflected beam; and detecting the beat frequency in the frequency up-conversion stage and the beat frequency in the frequency down-conversion stage between the local oscillator beam and the reflected beam to determine the speed of the object and / or the distance between the object and the laser radar.

[0005] Optionally, the scalar value of the beat frequency in the frequency up-conversion phase includes a positive value or a negative value of the beat frequency of the frequency up-conversion node; and the scalar value of the beat frequency in the frequency down-conversion phase includes a positive value or a negative value of the beat frequency in the frequency down-conversion phase.

[0006] Optionally, time delaying or frequency shifting at least one of the signal beam, the reflected beam and the local oscillator beam includes: time delaying the signal beam and the reflected beam, or time delaying the local oscillator beam so that the beat frequency of the up-conversion phase and the beat frequency of the down-conversion phase between the local oscillator beam and the reflected beam move toward the first direction or the second direction of the ranging spectrum of the laser radar.

[0007] Optionally, time delaying or frequency shifting at least one of the signal beam, the reflected beam and the local oscillator beam includes: frequency shifting the frequency of the signal beam or the local oscillator beam so that the beat frequency of the up-conversion phase and the beat frequency of the down-conversion phase between the local oscillator beam and the reflected beam are shifted toward the first direction or the second direction of the measurement spectrum.

[0008] Optionally, performing in-phase orthogonal coherent demodulation on the local oscillator beam and the reflected beam to obtain scalar values ​​of the beat frequency in the up-conversion stage and the beat frequency in the down-conversion stage between the local oscillator beam and the reflected beam includes: inputting the reflected beam and the local oscillator beam into a 90-degree mixing unit to obtain scalar values ​​of the beat frequency in the up-conversion stage and the beat frequency in the down-conversion stage between the local oscillator beam and the reflected beam.

[0009] Optionally, the minimum value of the scalar value of the beat frequency in the frequency up-conversion stage and the beat frequency in the frequency down-conversion stage is equal to the maximum negative frequency shift amount caused by the Doppler effect.

[0010] In a second aspect, the present invention provides a laser radar, comprising: a laser light source configured to generate a swept frequency beam; a spectrometer configured to split the swept frequency beam into a signal beam and a local oscillator beam; an optical transceiver configured to transmit the signal beam and receive a reflected beam generated by the signal beam being reflected from an object; a beat frequency scalar value acquirer configured to time delay or frequency shift at least one of the signal beam, the reflected beam and the local oscillator beam, and / or to perform in-phase orthogonal coherent demodulation on the local oscillator beam and the reflected beam so as to obtain scalar values ​​of the beat frequency in the up-conversion stage and the beat frequency in the down-conversion stage between the local oscillator beam and the reflected beam; and a detector configured to detect the beat frequency in the up-conversion stage and the beat frequency in the down-conversion stage between the local oscillator beam and the reflected beam so as to determine the speed of the object and / or the distance between the object and the laser radar.

[0011] Optionally, the scalar value of the beat frequency in the frequency up-conversion phase includes a positive value or a negative value of the beat frequency of the frequency up-conversion node; and the scalar value of the beat frequency in the frequency down-conversion phase includes a positive value or a negative value of the beat frequency in the frequency down-conversion phase.

[0012] Optionally, the beat frequency scalar value acquirer specifically includes: a time delay unit, configured to time delay the signal light beam and the reflected light beam, or time delay the local oscillator light beam, so that the beat frequency of the up-conversion stage and the beat frequency of the down-conversion stage between the local oscillator light beam and the reflected light beam move in the first direction or the second direction of the ranging spectrum of the laser radar.

[0013] Optionally, the beat frequency scalar value acquirer specifically includes: a frequency shifting unit, configured to shift the frequency of the signal light beam or the local oscillator light beam so that the beat frequency of the up-conversion stage and the beat frequency of the down-conversion stage between the local oscillator light beam and the reflected light beam are shifted toward the first direction or the second direction of the measurement spectrum.

[0014] Optionally, the beat frequency scalar value acquirer includes: a 90-degree mixing unit configured to receive the reflected light beam and the local oscillator light beam to obtain scalar values ​​of the beat frequency in the up-conversion stage and the beat frequency in the down-conversion stage between the local oscillator light beam and the reflected light beam.

[0015] Optionally, the minimum value of the scalar value of the beat frequency in the frequency up-conversion stage and the beat frequency in the frequency down-conversion stage is equal to the maximum negative frequency shift amount caused by the Doppler effect.

[0016] In a third aspect, the solution of the present application provides an autonomous vehicle, which includes the laser radar of the second aspect above.

[0017] The solution of the present application can obtain the beat frequencies of the frequency up-conversion stage and the frequency down-conversion stage, and can expand the measurement spectrum range of the laser radar, thereby avoiding the measurement blind spot caused by the beat frequency of the frequency up-conversion stage between the local oscillator beam and the reflected beam being outside the measurement spectrum range of the laser radar, thereby improving the measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of the structure of a continuous wave laser radar of the present application is shown;

[0019] Figure 2A The schematic diagram of measuring a stationary object using an existing triangular wave linear frequency modulation continuous wave laser radar is shown;

[0020] Figure 2B The schematic diagram of measuring a moving object using an existing triangular wave linear frequency modulation continuous wave laser radar is shown;

[0021] Figure 3 and Figure 4 A schematic diagram showing a measurement blind area caused by the Doppler effect when using existing laser radar measurement;

[0022] Figure 5A schematic diagram showing the principle of measuring a target object close to the laser radar using a triangular wave linear frequency modulation continuous wave laser radar using an IQ coherent demodulation method of the present application;

[0023] Figure 6 A schematic diagram showing the principle of measuring a target object far away from the laser radar by a triangular wave linear frequency modulation continuous wave laser radar using an IQ coherent demodulation method of the present application;

[0024] Figure 7 A schematic diagram of the process of the laser measurement method of the present application is shown;

[0025] Fig. 8A and Figure 8B A time-frequency domain schematic diagram of time delaying a signal light beam and a reflected light beam using the laser measurement method of the present application is shown;

[0026] Fig.9A and Fig. 9B A time-frequency domain schematic diagram of time delaying a local oscillator light beam using the laser measurement method of the present application is shown;

[0027] Fig.10 A schematic diagram showing the frequency shifting of a local oscillator light beam using the laser measurement method of the present application is shown;

[0028] Fig.11 A schematic diagram showing the frequency shifting of a signal light beam using the laser measurement method of the present application is shown;

[0029] Fig.12 A schematic diagram showing the expansion of the measurement spectrum of a laser radar using the laser measurement method of the present application is shown;

[0030] Fig.13 The structure of the laser radar of the present application is shown Figure 1 ;

[0031] Fig.14 A second structural diagram of the laser radar of the present application is shown;

[0032] Fig.15 The structure of the laser radar of the present application is shown Figure 3 ;.

[0033] Fig.16 The structure of the laser radar of the present application is shown Figure 4 ;as well as

[0034] Fig.17 and Fig.18 A schematic diagram of an autonomous vehicle including the lidar of the present application is shown. DETAILED DESCRIPTION

[0035] Below, the specific embodiments of the present application will be described in detail in conjunction with the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. In the following exemplary embodiments, the described embodiments are not all embodiments of the present application. On the contrary, they are only examples of devices and methods consistent with some aspects of the present application as detailed in the attached claims. In the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0036] refer to Figure 1 , Figure 1 It is a schematic diagram of the structure of the continuous wave laser radar of the present application. The continuous wave laser radar 1 of the present application adopts the working principle of coherent reception. By comparing the instantaneous frequency relationship between the reflected light beam reflected from the target object 2 and the local oscillator light beam of the laser radar 1, the distance between the target object 2 and the laser radar 1 and the speed of the target object can be given at the same time.

[0037] refer to Figure 2A , Figure 2A The schematic diagram of the principle of measuring a stationary object using an existing triangular wave linear frequency modulation continuous wave laser radar is shown. Figure 2A In the figure, the solid triangle wave is the instantaneous time-frequency relationship of the radar signal beam or the local oscillator beam, and the dotted triangle wave is the reflected beam of the stationary target object, where τ is the delay of the reflected beam of the stationary target object, f1 and f2 are the beat frequencies of the reflected beam of the stationary object in the up-sweep part and the down-sweep part (i.e., the beat frequency of the up-sweep stage and the beat frequency of the down-sweep stage between the reflected beam and the local oscillator beam), T is the period of the up-sweep and down-sweep, and f B is the sweep bandwidth of the linear frequency modulation. Figure 2A In the above example, the beat frequencies of the reflected light beam in the up-conversion stage and the down-conversion stage are:

[0038]

[0039]

[0040] Assume that the distance between the target object and the laser radar is R, then R = τ*c / 2, where c is the speed of light and λ is the wavelength of the laser. Figure 2A In the time-frequency diagram, the distance of the target object during the up-conversion phase of the reflected beam is shown below:

[0041]

[0042] Figure 2B The schematic diagram of measuring an object moving in the direction of the laser radar using an existing triangular wave linear frequency modulation continuous wave laser radar is shown. Figure 2BIn the figure, the solid triangle wave is the instantaneous time-frequency relationship of the radar signal beam or the local oscillator beam, and the dotted triangle wave is the reflected beam of the target object moving toward the direction of the lidar, where τ is the delay of the reflected beam of the target object, f1 and f2 are the beat frequencies of the reflected beam of the target object in the up-sweep part and the down-sweep part (i.e., the beat frequency of the up-sweep stage and the beat frequency of the down-sweep stage between the reflected beam and the local oscillator beam), T is the period of the up-sweep and down-sweep, and f B is the sweep bandwidth of the linear frequency modulation, f d =(f2-f1) / 2. Figure 2B In the above example, the beat frequencies of the reflected light beam in the up-conversion stage and the down-conversion stage are:

[0043]

[0044]

[0045] The distance R and speed ν of the target object are as follows:

[0046]

[0047] When f1 = 0, the relationship between the above distance and speed can be expressed as follows:

[0048]

[0049] In the above formula 4, in order to avoid measuring blind areas, the absolute values ​​of f1 and f2 are required, that is, both f1 and f2 are required to be greater than 0, and the actual distance between the laser radar and the target object needs to be greater than the value of R calculated by the above formula R m , that is, we need to ensure that the value of R>R m， Right now Less than the value R above m This will lead to errors in the calculation of speed and distance. In addition, it can be seen from Formula 5 that R is proportional to the speed ν of the target object. The larger the speed ν of the target object, the larger the R value above.

[0050] In addition, both Formula 3 and Formula 4 above assume that f2 and f1 are greater than 0, and the absolute values ​​of f1 and f2 above, i.e., positive values, are required to obtain the calculated distance R between the target object and the laser radar and the speed ν of the target object. However, when the actual speed ν of the target object is fast, the frequency shift caused by the Doppler effect may be greater than the frequency shift caused by the flight time of the reflected light beam, resulting in the actual value of the beat frequency f1 in the frequency-up phase between the received local oscillator light beam and the reflected light beam being a negative value, such as Figure 3 and Figure 4As shown. Although the beat frequency f1 in the frequency-up phase between the received local oscillator beam and the reflected beam is actually a negative value (less than 0), the laser radar judges the frequency f1 as a positive value (greater than 0). Therefore, when the above formula is used to calculate the distance and speed of the target object, errors will occur in the calculation of the distance and speed, resulting in a measurement blind spot. In addition, when the laser radar's rotating mirror device rotates at high speed, a large Doppler frequency shift will also be generated. The Doppler frequency shift introduced by the rotation of the rotating mirror and the Doppler frequency shift of the target object are superimposed on each other, which will also cause the frequency shift caused by the Doppler effect to exceed the frequency offset caused by the flight time of the reflected beam, resulting in errors in the calculation of the distance and speed of the target object, causing a measurement blind spot.

[0051] In view of the above problems, the scheme of the present application adopts the method of in-phase quadrature (IQ) coherent demodulation. The scheme of the present application obtains the real value of the beat frequency in the up-conversion stage and the beat frequency in the down-conversion stage between the reflected light beam and the local oscillator light beam, that is, the scheme of the present application obtains the scalar value (positive or negative value, i.e., value greater than 0 or less than 0) of the beat frequency of the upper sweep part and the beat frequency of the lower sweep part, instead of the absolute value of the beat frequency of the upper sweep part and the absolute value of the beat frequency of the lower sweep part (value only greater than 0), which can effectively avoid the ranging blind area.

[0052] refer to Figure 5 , Figure 5 This is a schematic diagram of the principle of using the IQ coherent demodulation method of the present application to measure a target object moving toward the laser radar. When the target object moves toward the laser radar, the frequency of the reflected light beam increases relative to the frequency of the local oscillator light beam. At this time, the beat frequencies of the reflected light beam in the up-conversion stage and the down-conversion stage are respectively:

[0053]

[0054]

[0055] The distance and speed of the target object are as follows:

[0056]

[0057] refer to Figure 6 , Figure 6 This is a schematic diagram of the principle of using the IQ coherent demodulation method of the present application to measure a target object moving away from the laser radar. When the target object moves away from the laser radar, the frequency of the reflected light beam decreases relative to the frequency of the local oscillator light beam. At this time, the beat frequencies of the reflected light beam in the up-conversion stage and the down-conversion stage are respectively:

[0058]

[0059]

[0060] The distance and speed of the target object are as follows:

[0061]

[0062] By adopting the above formulas 6-9, the solution of the present application can accurately obtain the scalar value of the beat frequency in the frequency up-conversion stage and the beat frequency in the frequency down-conversion stage, rather than just the absolute value, thereby expanding the measurement spectrum of the laser radar. In addition, when using the existing laser measurement method to measure the distance and speed of the target object, if the speed of the target object is too fast or the distance between it and the laser radar is too close, it may cause the beat frequency in the frequency up-conversion stage and the beat frequency in the frequency down-conversion stage to be outside the frequency range of the measurement spectrum of the existing laser radar, resulting in a blind spot in ranging, such as Figure 4 The solution of the present application accurately obtains the scalar value of the beat frequency in the frequency up-conversion stage and can avoid the ranging blind area.

[0063] In some embodiments, the present disclosure provides a laser measurement method. The laser measurement method can be applied to frequency modulated continuous wave (FMCW) laser radar, such as Figure 7 As shown, the laser measurement method includes the following steps S701-S705.

[0064] Step S701: Generate a frequency-sweeping light beam.

[0065] Specifically, the swept frequency beam can be generated by a laser light source. The laser light source can be directly modulated by a chirp signal drive of an optical signal. For example, a driving signal for controlling the laser light source can be input to the laser light source with an intensity that varies with time, so that the laser light source generates and outputs a swept frequency beam, i.e., a beam whose frequency varies within a predetermined range.

[0066] In some embodiments, the laser light source may further include a modulator that receives a modulation signal. The modulator may be configured to modulate the light beam based on the modulation signal to generate and output a swept frequency light beam, the frequency of which varies within a predetermined range. The principle of generating a swept frequency light beam by FMCW laser radar is well known to those skilled in the art. In order to save space, this article will not be further described here.

[0067] Step S702: Split the frequency-sweeping beam into a signal beam and a local oscillator beam.

[0068] In some examples, a beam splitter may be used to split the swept frequency beam into a signal beam and a local oscillator beam. The signal beam and the local oscillator beam have the same frequency at any point in time, that is, the frequency modulation waveforms of the signal beam and the local oscillator beam are exactly the same. In some examples, the beam splitter may be a specific wavelength coupler (splitter) for wavelengths of 445 to 2100 nm, such as a 1X2 beam splitter on an optical chip and a beam splitter of the SMC series. In other examples, other beam splitters known to those skilled in the art that can split the swept frequency beam into a signal beam and a local oscillator beam may also be used.

[0069] Step S703: emitting the signal light beam, and receiving a reflected light beam generated when the signal light beam is reflected from an object.

[0070] In some examples, an optical transmitter and receiver or an optical transceiver is used to emit the signal light beam at a predetermined angle, and a light receiver or the optical transceiver is used to receive reflected light reflected by the target object.

[0071] Step S704: time delay or frequency shift at least one of the signal beam, the reflected beam and the local oscillator beam, and / or perform in-phase orthogonal coherent demodulation on the local oscillator beam and the reflected beam, so as to obtain scalar values ​​of the beat frequency in the up-conversion stage and the beat frequency in the down-conversion stage between the local oscillator beam and the reflected beam.

[0072] In an embodiment of the present application, an IQ coherent demodulation method is used to measure a moving target object, and a scalar value (i.e., a value with a positive or negative sign) of the beat frequency f1 (i.e., the frequency difference) in the frequency up phase between the rising edge of the local oscillator beam and the rising edge of the reflected beam and the beat frequency f2 (i.e., the frequency difference) in the frequency down phase between the falling edge of the local oscillator beam and the falling edge of the reflected beam can be obtained, thereby making full use of the frequency range of the negative frequency band and expanding the measurement spectrum of the laser radar. The measurement spectrum of the laser radar refers to the frequency range of the beat frequency f1 in the frequency up phase and the beat frequency f2 in the frequency down phase that can be measured by the laser radar. In existing FMCW laser radars, the range of the measurement spectrum can be [0, +f max ], f maxIt is the maximum value of the beat frequency in the frequency-down phase between the local oscillator beam of the laser radar and the reflected beam. Therefore, the existing FMCW laser radar can only obtain the absolute value (positive value) of the beat frequency in the frequency-up phase and the beat frequency in the frequency-down phase. Due to the influence of the Doppler effect, when the distance between the target object and the laser radar is close enough or the relative speed is fast enough, the true value of the beat frequency f1 between the rising edge of the local oscillator beam and the rising edge of the reflected beam or the true value of the beat frequency f1 between the falling edge of the local oscillator beam and the falling edge of the reflected beam may be negative. Therefore, if the measurement spectrum of the existing laser radar is used, the true value of the beat frequency f1 in the frequency-up phase may be outside the range of the measurement spectrum, resulting in errors in the speed and distance calculation of the target object, resulting in a measurement blind spot, such as Figure 3 and 4 The present application adopts an IQ coherent demodulation scheme, which can obtain the scalar value (i.e., positive or negative value) of the beat frequency in the up-conversion stage and the beat frequency in the down-conversion stage, and can shift at least one of the beat frequency in the up-conversion stage and the beat frequency in the down-conversion stage between the local oscillator light beam and the reflected light beam according to the measurement needs, so that the beat frequency in the up-conversion stage and the beat frequency in the down-conversion stage are within the measurement spectrum range of the laser radar, thereby expanding the measurement spectrum of the laser radar, avoiding calculation errors of the speed and distance of the target object, and avoiding measurement blind spots.

[0073] Specifically, a 90-degree mixing unit can be used to obtain the measured values ​​of the beat frequency of the up-conversion stage and the beat frequency of the down-conversion stage of the laser radar. In some embodiments, the local oscillator beam and the reflected beam are coherently demodulated in phase orthogonal manner to obtain the scalar value of the beat frequency of the up-conversion stage and the beat frequency of the down-conversion stage between the local oscillator beam and the reflected beam, including: inputting the reflected beam and the local oscillator beam into the 90-degree mixing unit to obtain the scalar value of the beat frequency of the up-conversion stage and the beat frequency of the down-conversion stage between the local oscillator beam and the reflected beam. The 90-degree mixing unit can perform 90-degree mixing on the local oscillator beam and the reflected beam, and input the mixed signal into the first balanced detector and the second balanced detector for detection. The 90-degree mixing unit is configured to coherently mix the local oscillator light and the reflected light so that the relative phase differences of the four output ports are 0°, 90°, 180°, and 270°, respectively. The 90-degree mixing unit can be a 90-degree mixing unit known to those skilled in the art. This application is not described in detail here.

[0074] In some embodiments, time delaying or frequency shifting at least one of the signal beam, the reflected beam, and the local oscillator beam includes: time delaying the signal beam and the reflected beam, or time delaying the local oscillator beam, so that the beat frequency of the up-conversion phase and the beat frequency of the down-conversion phase between the local oscillator beam and the reflected beam move toward the first direction or the second direction of the ranging spectrum of the lidar.

[0075] like Fig. 8A As shown, in this embodiment, when both the signal beam and the reflected beam are delayed by Δt, when the target object moves away from the laser radar, the beat frequencies of the reflected beam in the frequency-increasing stage and the frequency-decreasing stage are respectively:

[0076]

[0077]

[0078] The distance and speed of the target object are as follows:

[0079]

[0080] When the target object moves toward the lidar, the frequency of the reflected beam increases relative to the frequency of the local oscillator beam. At this time, the beat frequencies of the reflected beam in the up-conversion stage and the down-conversion stage are:

[0081]

[0082]

[0083] The distance and speed of the target object are as follows:

[0084]

[0085] like Figure 8B As shown in the figure, when Δt increases, the beat frequency f1 in the frequency-up phase and the beat frequency f2 in the frequency-down phase between the local oscillator light beam and the reflected light beam move in opposite directions, thereby increasing the spacing. Vice versa, when Δt decreases, the beat frequency f1 in the frequency-up phase and the beat frequency f2 in the frequency-down phase between the local oscillator light beam and the reflected light beam move in opposite directions, thereby decreasing the spacing. When Δt continues to decrease, the beat frequency f1 in the frequency-up phase and the beat frequency f2 in the frequency-down phase may pass each other and move in opposite directions, thereby increasing the spacing.

[0086] like Fig.9A As shown, in this embodiment, the local oscillator signal is delayed by Δt. When the target object moves away from the laser radar, the beat frequencies of the reflected light beam in the frequency-increasing stage and the frequency-decreasing stage are respectively:

[0087]

[0088]

[0089] The distance and speed of the target object are as follows:

[0090]

[0091] When the target object moves toward the lidar, the frequency of the reflected beam increases relative to the frequency of the local oscillator beam. At this time, the beat frequencies of the reflected beam in the up-conversion stage and the down-conversion stage are:

[0092]

[0093]

[0094] The distance and speed of the target object are as follows:

[0095]

[0096] like Fig. 9B As shown in the figure, when Δt increases, the beat frequency f1 in the frequency-up phase and the beat frequency f2 in the frequency-down phase between the local oscillator light beam and the reflected light beam move in opposite directions, thereby reducing the spacing. When Δt continues to increase, the beat frequency f1 in the frequency-up phase and the beat frequency f2 in the frequency-down phase can cross each other and move in opposite directions, thereby increasing the spacing. Vice versa, when Δt decreases, the beat frequency f1 in the frequency-up phase and the beat frequency f2 in the frequency-down phase between the local oscillator light beam and the reflected light beam move in opposite directions, thereby increasing the spacing.

[0097] In the above embodiment, both the signal beam and the reflected beam can be time delayed, and the local oscillator beam can also be time delayed. By time delaying one or more of the signal beam, the reflected beam and the local oscillator beam, the position of the beat frequency f1 in the frequency up-conversion phase and the beat frequency f2 in the frequency down-conversion phase between the local oscillator beam and the reflected beam on the measurement spectrum of the laser radar can be changed, and the speed of the target object and the distance and speed between the laser radar and the target object can be correctly calculated according to the above formula, thereby avoiding the measurement blind area and improving the measurement accuracy. In addition, since time delay is used, the time delay system can be used as a measurement scale of the laser radar measurement system to accurately obtain the position of the measurement zero point.

[0098] In some embodiments, a time delayer may be used to shift the frequency of the signal beam and the reflected beam. The number of time delayers may be one or more (e.g., multiple time delayers in series, such as delay optical fibers), so that one or more of the signal beam, the reflected beam, and the local oscillator beam are all time delayed. The parameters of the time delayer may be defined according to the performance of the laser radar system and the maximum moving speed of the target object, and will not be described in detail in this application.

[0099] In some embodiments, time delaying or frequency shifting at least one of the signal beam, the reflected beam, and the local oscillator beam includes: frequency shifting the frequency of the signal beam or the local oscillator beam so that the beat frequency of the up-conversion phase and the beat frequency of the down-conversion phase between the local oscillator beam and the reflected beam are shifted toward the first direction or the second direction of the measurement spectrum.

[0100] In some embodiments, the first direction of the measured spectrum is the direction of increasing frequency, that is, the positive frequency direction. Figure 4 The second direction of measuring the spectrum is the direction of decreasing frequency, that is, the negative frequency direction.

[0101] In some embodiments, when the frequency of the local oscillator light beam is shifted, the frequency of the local oscillator light beam may be increased or decreased as a whole. Fig.10 As shown, the frequency of the local oscillator beam is increased by Δf as a whole. When the target object moves away from the laser radar, the beat frequencies in the frequency up-conversion stage and the frequency down-conversion stage are:

[0102]

[0103]

[0104] The distance and speed of the target object are as follows:

[0105]

[0106] When the target object moves toward the lidar, the beat frequencies in the up-conversion phase and the down-conversion phase are:

[0107]

[0108]

[0109] The distance and speed of the target object are as follows:

[0110]

[0111] In some embodiments, when the frequency of the signal beam is shifted, the frequency of the signal may be increased or decreased as a whole. Fig.11 As shown, the frequency of the signal beam is increased by Δf as a whole. When the target object moves away from the laser radar, the beat frequency in the up-conversion stage and the beat frequency in the down-conversion stage are:

[0112]

[0113]

[0114] The distance and speed of the target object are as follows:

[0115]

[0116] When the target object moves toward the lidar, the beat frequencies in the up-conversion phase and the down-conversion phase are:

[0117]

[0118]

[0119] The distance and speed of the target object are as follows:

[0120]

[0121] In some embodiments, a minimum value of the scalar value of the beat frequency in the up-conversion phase and the beat frequency in the down-conversion phase is equal to a maximum negative frequency shift amount caused by the Doppler effect.

[0122] In the embodiments of the present disclosure, Fig.12 As shown, by shifting the frequency of the local oscillator beam and / or the signal beam, the position of the beat frequency in the frequency up-conversion stage and the beat frequency in the frequency down-conversion stage on the measurement spectrum of the laser radar system can be changed. In combination with the in-phase orthogonal coherent demodulation method of the present application, the measurement spectrum of the laser radar system can be changed from [0, f max ] expands to [-f max ,f max ], thus avoiding the measurement blind area.

[0123] Step S705: Detect the beat frequency of the up-conversion phase and the beat frequency of the down-conversion phase between the local oscillator light beam and the reflected light beam to determine the speed of the object and / or the distance between the object and the laser radar.

[0124] Specifically, a balanced detector can be used to measure the beat frequency of the local oscillator light beam and the reflected light beam. The balanced detector can be a photoelectric detector.

[0125] In some embodiments, step S705 specifically includes: mixing the received reflected light beam with the local oscillator light beam to obtain a mixed signal.

[0126] The local oscillator light beam is mixed with the received reflected light beam by a mixer to obtain a mixed signal. The mixing device may be a coupler, such as a 2×2 coupler, and the mixed signal may be a coherent signal generated by interference between the local oscillator light beam and the corresponding reflected light beam. The mixer or coupler may be a mixer and a coupler well known to those skilled in the art. In order to save space, this application will not be described in detail.

[0127] The above-mentioned scheme of the present application obtains the true value of the beat frequency in the frequency-upgrading stage between the local oscillator beam and the reflected beam, so that the measurement spectrum of the laser radar is expanded, the measurement blind area is avoided, and the measurement accuracy is improved.

[0128] Fig.13 The structure of the laser radar of the present application is shown as follows Figure 1 In this embodiment, the laser radar includes a laser light source 1301, configured to generate a swept frequency beam; a beam splitter 1302, configured to split the swept frequency beam into a signal beam and a local oscillator beam; an optical transceiver 1303, configured to transmit the signal beam and receive a reflected beam generated by the signal beam reflecting from an object; a beat frequency scalar value acquirer 1304, configured to time delay or frequency shift at least one of the signal beam, the reflected beam and the local oscillator beam, and / or to perform in-phase orthogonal coherent demodulation on the local oscillator beam and the reflected beam, so as to obtain the scalar value of the beat frequency in the up-conversion stage and the beat frequency in the down-conversion stage between the local oscillator beam and the reflected beam; and a detector 1305, configured to detect the beat frequency in the up-conversion stage and the beat frequency in the down-conversion stage between the local oscillator beam and the reflected beam, so as to determine the speed of the object and / or the distance between the object and the laser radar.

[0129] In some embodiments, the scalar value of the beat frequency in the up-conversion phase includes a positive value or a negative value of the beat frequency of the up-conversion node; the scalar value of the beat frequency in the down-conversion phase includes a positive value or a negative value of the beat frequency in the down-conversion phase.

[0130] In some embodiments, the beat frequency scalar value acquirer 1304 specifically includes: a time delay unit, configured to time delay the signal beam and the reflected beam, or time delay the local oscillator beam, so that the beat frequency of the up-conversion stage and the beat frequency of the down-conversion stage between the local oscillator beam and the reflected beam move toward the first direction or the second direction of the ranging spectrum of the laser radar.

[0131] In some embodiments, the beat frequency scalar value acquirer 1304 specifically includes: a frequency shifting unit, configured to shift the frequency of the signal light beam or the local oscillator light beam so that the beat frequency of the up-conversion stage and the beat frequency of the down-conversion stage between the local oscillator light beam and the reflected light beam are shifted toward the first direction or the second direction of the measurement spectrum.

[0132] In some embodiments, the beat frequency scalar value acquirer 1304 specifically includes: a 90-degree mixing unit configured to receive the reflected light beam and the local oscillator light beam to obtain the scalar values ​​of the beat frequency in the up-conversion stage and the beat frequency in the down-conversion stage between the local oscillator light beam and the reflected light beam.

[0133] Optionally, the minimum value of the scalar value of the beat frequency in the frequency up-conversion stage and the beat frequency in the frequency down-conversion stage is equal to the maximum negative frequency shift amount caused by the Doppler effect.

[0134] The device of the present application can implement the relevant steps of the above method embodiment. The same description can be found in the relevant description of the above method. In order to save space, the present application will not repeat the description here.

[0135] The detailed structure of the laser radar of the present application is described below. Fig.14 , Fig.14 FIG2 is a detailed structural diagram of the laser radar of the present application. The laser radar 1400 of the present application includes a laser light source 1401, a beam splitter 1402, an optical transceiver 1303, a first delay device 1304, a 2×2 optical coupler 1305, a balanced detector 1306, a target object 1307, and a second delay device or a first frequency shifter 1308.

[0136] The laser source 1401 is configured to generate a swept frequency beam. The laser light source 1401 can be driven by direct modulation of a chirp signal of an optical signal. For example, a driving signal for controlling the laser source 1401 can be input to the laser source 1401 with an intensity that varies with time, so that the laser source 1401 generates and outputs a swept frequency beam, i.e., a beam whose frequency varies within a predetermined range. The laser source 1401 may also include a modulator that receives a modulation signal. The modulator may be configured to modulate the light beam based on the modulation signal to generate and output a swept frequency beam, the frequency of which varies within a predetermined range. The laser light source 1401 may be a laser source commonly used in FMCW laser radars, and in order to save space, this application will not be described in detail.

[0137] The optical splitter 1402 is configured to split the frequency-sweeping beam into a signal beam and a local oscillator beam. The signal beam and the local oscillator beam have the same frequency at any point in time, that is, the frequency modulation waveforms of the signal beam and the local oscillator beam are exactly the same. In some examples, the optical splitter 1402 can be specifically a specific wavelength coupler (optical splitter) for wavelengths of 445 to 2100 nm, such as an SMC series optical splitter. In other examples, other optical splitters known to those skilled in the art that can split the frequency-sweeping beam into a signal beam and a local oscillator beam can also be used.

[0138] The signal light beam is incident on the light incident port of the optical transceiver 1403. The optical transceiver 1403 is configured to emit the signal light to the first delay device 1404. The first delay device 1404 can be specifically a time delay device or other device that can delay the light. The first delay device 1404 is configured to delay the signal light from the optical transceiver 1303.

[0139] The first delay device 1404 directs the time-delayed signal light beam toward the target object 1407. The reflected light of the time-delayed signal light beam after being reflected on the target object 1407 is delayed by the first delay device 1404, and the time-delayed reflected light beam reaches the optical transceiver 1403. The optical transceiver 1403 inputs the time-delayed reflected light beam to the input end of the 2×2 coupler 1405. The second delay device or the first frequency shifter 1408 is configured to delay or frequency-shift the local oscillator light beam. The principle of delaying the signal light beam and the reflected light beam and the specific principle of delaying and frequency-shifting the local oscillator light beam can be found in the above related description. This application will not be described in detail here.

[0140] The 2×2 optical coupler 1405 is configured to mix the local oscillator light and the reflected light. The mixed signal is, for example, a coherent signal generated by the interference between the local oscillator light beam and the corresponding reflected light beam. The mixed signals are respectively sent to the photodetector 1406 for detection.

[0141] The device of the present application can implement the relevant steps of the above method embodiment. The same description can be found in the relevant description of the above method. In order to save space, the present application will not repeat the description here.

[0142] The laser radar 1400 of this embodiment of the present application can time delay both the signal beam and the reflected beam, and can also delay or frequency shift the local oscillator beam, and can change the position of the beat frequency in the up-conversion stage and the beat frequency in the down-conversion stage between the local oscillator beam and the reflected beam on the measurement spectrum, thereby expanding the measurement spectrum and avoiding the measurement blind spot generated when calculating the distance and speed of the target object.

[0143] Fig.15 The detailed structure of the laser radar of this application is shown Figure 3 The laser radar 1500 of the present application includes a laser light source 1501 , a first beam splitter 1502 , an optical transceiver 1503 , a target object 1504 , a 90-degree mixer 1505 , a first balanced detector 1506 , and a second balanced detector 1507 .

[0144] The laser source 1501 is configured to generate a swept frequency beam. The laser light source 1501 can be directly modulated by a chirp signal drive of an optical signal. The laser source 1501 can also include a modulator that receives a modulation signal. The modulator can be configured to modulate the light beam based on the modulation signal to generate and output a swept frequency beam, the frequency of which varies within a predetermined range.

[0145] The first optical splitter 1502 is configured to split the frequency-sweeping beam into a signal beam and a local oscillator beam. The signal beam and the local oscillator beam have the same frequency at any time point, that is, the frequency modulation waveforms of the signal beam and the local oscillator beam are exactly the same. The first optical splitter 1502 can be specifically a specific wavelength coupler (optical splitter) for wavelengths of 445 to 2100 nm, such as an SMC series optical splitter.

[0146] The signal light beam is incident on the light incident port of the optical transceiver 1503. The optical transceiver 1503 is configured to emit the signal light to the target object 1504. The reflected light after the signal light is reflected on the target object 1504 is captured by the optical transceiver 1503. The optical transceiver 1503 inputs the reflected light to the first port of the 90-degree mixer 1505.

[0147] The 90-degree mixer 1505 is configured to perform 90-degree mixing on the local oscillator light beam and the reflected light beam, and input the mixed signals to the first balanced detector 1506 and the second balanced detector 1507 for detection.

[0148] The 90-degree mixer includes a first input port, a second input port, a first output port, a second output port, a third output port, and a fourth output port. The 90-degree mixer is configured to coherently mix the local oscillator light and the reflected light so that the relative phase differences of the four output ports are 0°, 90°, 180°, and 270°, respectively.

[0149] The 90 degree mixer may be any 90 degree mixer known to those skilled in the art. Fig.15 An example of a 90-degree mixer is shown. The 90-degree mixer 1505 includes a third optical beam splitter 15051, a fourth optical beam splitter 15052, a first 2×2 coupler 15053, and a second 2×2 coupler 15054. The third optical beam splitter 15051 is configured to receive a local oscillator beam from the first optical splitter 1502. The local oscillator beam is split into two beams, which are respectively input to the first 2×2 coupler 15053 and the second 2×2 coupler 15054. The fourth optical beam splitter 15052 is configured to receive a reflected beam from the optical transceiver 1503. The reflected beam is split into two beams, which are respectively input to the first 2×2 coupler 15053 and the second 2×2 coupler 15054.

[0150] The first 2×2 coupler 15053 is configured to couple the two light beams from the third optical beam splitter 15051 and the fourth optical beam splitter 15052 into two light beams with phases of 0° and 180°, respectively, and input the two light beams through the first output port and the second output port to the first balanced detector 1506. The first balanced detector 1506 includes a photodetector 1 and a photodetector 2, which are connected in series.

[0151] The second 2×2 coupler 15054 is configured to couple the two light beams from the third optical beam splitter 15051 and the fourth optical beam splitter 15052 into two light beams with phases of 90° and 270°, respectively. And the two light beams are input to the second balanced detector 1507 through the third output port and the fourth output port. The second balanced detector 1507 includes a photodetector 3 and a photodetector 4. The photodetector 3 and the photodetector 4 are connected in series. The photodetector 3 is configured to receive the output light at 90°, and the photodetector 4 is configured to receive the output light at 270°.

[0152] The DC components of the photocurrents obtained by the balanced detectors for the light beams at 0° and 180° and 90° and 270° are equal.

[0153] This application Fig.15 The laser measuring device shown uses an IQ coherent demodulation method to obtain the scalar value of the beat frequency in the frequency up-conversion phase and the beat frequency in the frequency down-conversion phase, which can avoid the measurement blind area. The laser measuring device can implement the method steps described above. The relevant content of the laser measuring device 1500 can be found in the above Figure 7 This article will not repeat the description here.

[0154] By using a 90-degree mixer 1505, a first balanced detector 1506 and a second balanced detector 1507, the true values ​​of the beat frequency in the up-conversion stage and the beat frequency in the down-conversion stage between the local oscillator beam and the reflected beam can be obtained, and the beat frequency in the up-conversion stage and the beat frequency in the down-conversion stage can be shifted, thereby expanding the measurement spectrum of the laser radar and avoiding the measurement blind area.

[0155] Fig.16 The detailed structure of the laser radar of this application is shown Figure 4 . Fig.16 The lidar shown is Fig.15 The laser radar shown in the figure is similar, except that the local oscillator light output by the first beam splitter 1602 passes through the third delayer / third frequency shifter 1608 before reaching the 90-degree mixer 1605. The third delayer / third frequency shifter 1608 can time delay or frequency shift the local oscillator beam. The third delayer 1608 is configured to time delay the local oscillator beam. The third frequency shifter 1608 is configured to frequency shift the local oscillator beam. By delaying or frequency shifting the local oscillator beam, the beat frequency of the up-conversion phase and the beat frequency of the down-conversion phase between the local oscillator beam obtained by the laser radar and the reflected beam can be moved to the negative direction of the measurement spectrum, thereby expanding the range of the measurement spectrum, avoiding the measurement blind area caused by the beat frequency of the up-conversion phase and the beat frequency of the down-conversion phase between the local oscillator beam and the reflected beam being outside the measurement spectrum range of the laser radar, and improving the measurement accuracy.

[0156] Fig.16 The working principles of other components and devices shown are similar to Fig.15 The working principles of the corresponding elements shown are similar. The specific contents will not be described again to save space. The laser radar 1600 of the present application can make full use of the negative frequency range, expand the measurement spectrum of the laser radar, realize the full utilization of the spectrum, and improve the measurement accuracy.

[0157] Fig.17 and Fig.18 An example autonomous vehicle 1700 according to an embodiment of the present application is illustrated, which may include the present application Figure 13-15 Any component of the LIDAR device shown. The autonomous vehicle 1700 shown includes a sensor array configured to capture one or more objects of the external environment of the autonomous vehicle and generate sensor data related to the captured one or more objects for controlling the operation of the autonomous vehicle 1700. Fig.17 Sensors 1701 , 1702 , 1703 , 1704 , and 1705 are shown. Fig.18 Sensors 1701 , 1702 , 1703 , 1704 , 1705 , 1706 , 1707 , 1708 , and 1709 are illustrated. Fig.18 Shown is a top view of autonomous vehicle 1700. Any of sensors 1701, 1702, 1703, 1704, 1705, 1706, 1707, 1708, and 1709 may include the Figure 13-15 The laser radar device shown includes Figure 1 -Any LIDAR components of FIG. 9. The autonomous vehicle may include a powertrain including a prime mover powered by an energy source and capable of powering a drivetrain. The autonomous vehicle may also include a control system including directional control, powertrain control, and braking control. The autonomous vehicle may be implemented as any number of different vehicles, including vehicles capable of transporting people and / or cargo and capable of traveling in a variety of different environments. It should be understood that the above-described components can vary widely based on the type of vehicle utilizing the components.

[0158] The details of this embodiment of the present invention can be referred to the description of the aforementioned method embodiment. To avoid repetition, the present invention will not be described again here.

[0159] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0160] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0161] In the several embodiments provided by the present invention, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0162] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the embodiments of the present invention.

[0163] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0164] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the relevant technology or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk, etc., various media that can store program codes.

[0165] The computer-readable storage medium mentioned in the present invention may be volatile or non-volatile.

[0166] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A laser measurement method applied to laser radar, characterized in that: The method comprises: generating a swept beam; Splitting the frequency-sweeping beam into a signal beam and a local oscillator beam; emitting the signal light beam; receiving a reflected light beam generated when the signal light beam is reflected by an object; Performing time delay or frequency shift on at least one of the signal beam, the reflected beam and the local oscillator beam, and / or performing in-phase orthogonal coherent demodulation on the local oscillator beam and the reflected beam, so as to obtain scalar values ​​of the beat frequency in the frequency up-conversion phase and the beat frequency in the frequency down-conversion phase between the local oscillator beam and the reflected beam; and The beat frequency of the up-conversion phase and the beat frequency of the down-conversion phase between the local oscillator light beam and the reflected light beam are detected to determine the speed of the object and / or the distance between the object and the laser radar.

2. The laser measurement method according to claim 1, characterized in that: The scalar value of the beat frequency in the up-conversion phase includes a positive value or a negative value of the beat frequency of the up-conversion node; The scalar value of the beat frequency in the frequency reduction phase includes a positive value or a negative value of the beat frequency in the frequency reduction phase.

3. The laser measurement method according to claim 1 or 2, characterized in that: Performing time delay or frequency shift on at least one of the signal light beam, the reflected light beam, and the local oscillator light beam comprises: The signal light beam and the reflected light beam are time delayed, or the local oscillator light beam is time delayed, so that the beat frequency of the up-conversion phase and the beat frequency of the down-conversion phase between the local oscillator light beam and the reflected light beam move toward the first direction or the second direction of the ranging spectrum of the laser radar.

4. The laser measurement method according to claim 1 or 2, characterized in that: Performing time delay or frequency shift on at least one of the signal light beam, the reflected light beam, and the local oscillator light beam comprises: The frequency of the signal light beam or the local oscillator light beam is shifted so that the beat frequency of the frequency increase phase and the beat frequency of the frequency decrease phase between the local oscillator light beam and the reflected light beam are shifted toward the first direction or the second direction of the measurement spectrum.

5. The laser measurement method according to claim 1 or 2, characterized in that: Performing in-phase orthogonal coherent demodulation on the local oscillator light beam and the reflected light beam to obtain a scalar value of a beat frequency in a frequency-increasing phase and a beat frequency in a frequency-decreasing phase between the local oscillator light beam and the reflected light beam comprises: The reflected light beam and the local oscillator light beam are input into a 90-degree frequency mixing unit to obtain scalar values ​​of the beat frequency in the up-conversion phase and the beat frequency in the down-conversion phase between the local oscillator light beam and the reflected light beam.

6. The laser measurement method according to claim 5, characterized in that: The minimum value of the scalar value of the beat frequency in the frequency increasing stage and the beat frequency in the frequency decreasing stage is equal to the maximum negative frequency shift amount caused by the Doppler effect.

7. A laser radar, characterized in that: The laser radar comprises: a laser light source configured to generate a swept beam; A beam splitter configured to split the frequency-sweeping beam into a signal beam and a local oscillator beam; an optical transceiver configured to transmit the signal light beam and receive a reflected light beam generated when the signal light beam is reflected by an object; a beat frequency scalar value acquirer, configured to time delay or frequency shift at least one of the signal light beam, the reflected light beam and the local oscillator light beam, and / or perform in-phase orthogonal coherent demodulation on the local oscillator light beam and the reflected light beam, so as to obtain scalar values ​​of the beat frequency in the frequency up-conversion stage and the beat frequency in the frequency down-conversion stage between the local oscillator light beam and the reflected light beam; and The detector is configured to detect the beat frequency of the up-conversion phase and the beat frequency of the down-conversion phase between the local oscillator beam and the reflected beam to determine the speed of the object and / or the distance between the object and the laser radar.

8. The laser radar according to claim 7, characterized in that: The scalar value of the beat frequency in the up-conversion phase includes a positive value or a negative value of the beat frequency of the up-conversion node; The scalar value of the beat frequency in the frequency reduction phase includes a positive value or a negative value of the beat frequency in the frequency reduction phase.

9. The laser radar according to claim 7 or 8, characterized in that: The beat frequency scalar value acquirer specifically includes: The time delay unit is configured to time delay the signal light beam and the reflected light beam, or time delay the local oscillator light beam, so that the beat frequency of the up-conversion phase and the beat frequency of the down-conversion phase between the local oscillator light beam and the reflected light beam move toward the first direction or the second direction of the ranging spectrum of the laser radar.

10. The laser radar according to claim 7 or 8, characterized in that: The beat frequency scalar value acquirer specifically includes: The frequency shifting unit is configured to shift the frequency of the signal beam or the local oscillator beam so that the beat frequency of the up-conversion phase and the beat frequency of the down-conversion phase between the local oscillator beam and the reflected beam are moved to the first direction or the second direction of the measurement spectrum.

11. The laser radar according to claim 7 or 8, characterized in that: The beat frequency scalar value getter includes: The 90-degree frequency mixing unit is configured to receive the reflected light beam and the local oscillator light beam to obtain the scalar value of the beat frequency in the up-conversion phase and the beat frequency in the down-conversion phase between the local oscillator light beam and the reflected light beam.

12. The laser radar according to claim 11, characterized in that: The minimum value of the scalar value of the beat frequency in the frequency up-conversion stage and the beat frequency in the frequency down-conversion stage is equal to the maximum negative frequency shift amount caused by the Doppler effect.

13. An autonomous vehicle comprising: A laser radar according to any one of claims 7 to 12.

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