A method for detecting target motion direction based on frequency modulated continuous wave laser radar

Abstract

A method for detecting the direction of target movement based on a frequency modulated continuous wave laser radar, the method comprising: obtaining a first difference frequency signal generated by mixing a transmitting signal and an echo signal within a single frequency sweep period T, the transmitting signal being a signal transmitted by a frequency modulated continuous wave laser radar based on triangular wave modulation, and the echo signal being an echo signal after the transmitting signal is reflected by a moving target; setting the difference frequency signal data of a certain duration t within half a frequency sweep period of the first difference frequency signal to zero to obtain a second difference frequency signal; and determining the speed information of the moving target relative to the laser radar based on the frequency values ​​of the two spectral peaks in the spectrum data corresponding to the second difference frequency signal, the speed information including the speed magnitude and direction. This application establishes a corresponding relationship between the spectrum amplitude and the spectrum of the difference frequency signal in the upper and lower frequency sweep bands, and the speed information between the target and the radar can be obtained by measuring the frequency difference between the upper and lower frequency sweep bands.

Description

Technical Field

[0001] The present application belongs to the field of laser radar detection technology, and in particular relates to a method for detecting the direction of target motion based on a frequency modulated continuous wave laser radar. Background Art

[0002] Frequency-modulated continuous-wave (FMCW) lidars based on triangular wave modulation transmit a continuous wave with varying frequency within a sweep cycle. The echo reflected by an object has a certain frequency difference from the transmitted signal. If there is no Doppler shift, the frequency difference during the rising edge is equal to the frequency difference during the falling edge. For moving targets, the frequency difference during the rising and falling edges is different. These two frequency differences are used to calculate the distance and velocity between the target and the radar.

[0003] For triangular wave modulated FMCW lidar, when a single sweep cycle is used as the unit for calculating velocity information, after Fourier transforming the difference frequency signal generated by mixing the echo signal of the moving target with the transmitted signal, the correspondence between the spectrum of the difference frequency signal and the upper and lower sweep frequency bands cannot be clearly determined. Therefore, in the process of calculating velocity information, it is difficult to determine the positive or negative sign of the velocity information, and thus it is impossible to determine the direction of motion of the target. Summary of the Invention

[0004] The purpose of this application is to provide a method and device for detecting the target motion direction based on a frequency modulated continuous wave laser radar, aiming to solve the problem that the frequency modulated continuous wave laser radar has difficulty in distinguishing the target motion direction.

[0005] A first aspect of an embodiment of the present application provides a method for detecting a target's motion direction based on a frequency modulated continuous wave laser radar, the method comprising the following steps:

[0006] Acquire a first difference frequency signal generated by mixing a transmission signal and an echo signal within a single frequency sweep period T, wherein the transmission signal is a signal transmitted by a frequency modulated continuous wave lidar based on triangular wave modulation, and the echo signal is an echo signal after the transmission signal is reflected by a moving target;

[0007] The difference frequency signal data of a certain time length t within half the frequency sweep period of the first difference frequency signal is set to zero to obtain a second difference frequency signal, wherein, 0 <t<T / 2;

[0008] The speed information of the moving target relative to the laser radar is determined according to the frequency values ​​of the two spectrum peaks in the spectrum data corresponding to the second difference frequency signal, where the speed information includes the speed magnitude and direction.

[0009] Furthermore, the difference frequency signal data with a duration of t within half a frequency sweep period of the difference frequency signal is set to zero to obtain a second difference frequency signal, including:

[0010] Setting the difference frequency signal data of a certain duration t within the first half of the frequency sweep period of the difference frequency signal to zero to obtain the second difference frequency signal; or

[0011] The difference frequency signal data of a certain duration t within the second half of the frequency sweep period of the difference frequency signal is set to zero to obtain the second difference frequency signal.

[0012] Furthermore, after obtaining the second difference frequency signal, the method further includes:

[0013] Performing Fourier transform on the second difference frequency signal to obtain frequency spectrum data corresponding to the second difference frequency signal.

[0014] Furthermore, after obtaining the spectrum data corresponding to the second difference frequency signal, the method further includes:

[0015] In the spectrum data corresponding to the second difference frequency signal, two spectrum peaks with the largest amplitude values ​​are determined as a first spectrum peak and a second spectrum peak, and the amplitude value of the first spectrum peak is greater than the amplitude value of the second spectrum peak.

[0016] Furthermore, after determining the two spectrum peaks with the largest amplitude values ​​as the first spectrum peak and the second spectrum peak, the method further includes:

[0017] The frequency value of the first spectrum peak and the frequency value of the second spectrum peak are determined.

[0018] Furthermore, after determining the frequency value of the first spectrum peak and the frequency value of the second spectrum peak, the method further includes:

[0019] When the difference frequency signal data of a certain duration t within the first half of the frequency sweep period of the difference frequency signal is set to 0, the frequency value f2 of the second spectrum peak is determined as the frequency difference value fb+ of the first half of the frequency sweep period, and the frequency value f1 of the first spectrum peak is determined as the frequency difference value fb- of the second half of the frequency sweep period; or

[0020] When the difference frequency signal data of a certain duration t within the second half of the frequency sweep cycle of the difference frequency signal is set to 0, the frequency value f1 corresponding to the first spectrum peak is determined as the frequency difference fb+ of the first half of the frequency sweep cycle, and the frequency value f2 corresponding to the second spectrum peak is determined as the frequency difference fb- of the second half of the frequency sweep cycle.

[0021] Furthermore, determining the speed information of the moving target relative to the laser radar based on the frequency values ​​of the two spectrum peaks in the spectrum data corresponding to the second difference frequency signal includes:

[0022] Calculate the speed information of the moving target by formula (1);

[0023]

[0024] Wherein, v represents the relative radial motion speed between the moving target and the laser radar, f is the center frequency of the transmitted signal, c is the speed of light, fb+ ​​represents the frequency difference of the first half of the sweep cycle, and fb- represents the frequency difference of the second half of the sweep cycle.

[0025] Further, determining the speed information of the moving target relative to the laser radar according to the frequency values ​​of the two spectrum peaks in the spectrum data corresponding to the second difference frequency signal includes:

[0026] When fb+ is less than fb-, v is a positive value, and determining the velocity information of the moving target relative to the laser radar includes: the moving target moves toward the laser radar; or

[0027] When the fb+ is greater than the fb-, v is a negative value, and determining the speed information of the moving target relative to the laser radar includes: the moving target moves away from the laser radar.

[0028] Further, determining the speed information of the moving target relative to the laser radar according to the frequency values ​​of the two spectrum peaks in the spectrum data corresponding to the second difference frequency signal includes:

[0029] When the fb+ is equal to the fb-, v is zero, and determining the speed information of the moving target relative to the laser radar includes: the moving target is stationary relative to the laser radar.

[0030] A second aspect of the embodiments of the present application provides a target motion direction detection device based on a frequency modulated continuous wave laser radar, characterized in that it includes an acquisition module and a processing module:

[0031] The acquisition module is used to acquire a first difference frequency signal generated by mixing a transmission signal and an echo signal within a single frequency sweep period T, wherein the transmission signal is a signal transmitted by a frequency modulated continuous wave laser radar based on triangular wave modulation, and the echo signal is an echo signal after the transmission signal is reflected by a moving target;

[0032] The processing module is used to set the difference frequency signal data of a certain duration t within half a frequency sweep period of the first difference frequency signal to zero to obtain a second difference frequency signal, wherein 0 <t<T / 2;

[0033] The processing module is further used to determine the speed information of the moving target relative to the laser radar based on the frequency values ​​of two spectrum peaks in the spectrum data corresponding to the second difference frequency signal, where the speed information includes the speed magnitude and direction.

[0034] Furthermore, the processing module is further configured to:

[0035] The two spectrum peaks with the largest amplitude values ​​in the spectrum data corresponding to the second difference frequency signal are determined as the first spectrum peak and the second spectrum peak, the amplitude value of the first spectrum peak is greater than the amplitude value of the second spectrum peak, and the frequency values ​​of the two spectrum peaks are determined.

[0036] Furthermore, the processing module is further configured to:

[0037] When the difference frequency signal data of a certain duration t within the first half of the frequency sweep period of the difference frequency signal is set to 0, the frequency value f2 of the second spectrum peak is determined as the frequency difference value fb+ of the first half of the frequency sweep period, and the frequency value f1 of the first spectrum peak is determined as the frequency difference value fb- of the second half of the frequency sweep period; or

[0038] When the difference frequency signal data of a certain duration t within the second half of the frequency sweep cycle of the difference frequency signal is set to 0, the frequency value f1 corresponding to the first spectrum peak is determined as the frequency difference fb+ of the first half of the frequency sweep cycle, and the frequency value f2 corresponding to the second spectrum peak is determined as the frequency difference fb- of the second half of the frequency sweep cycle.

[0039] Furthermore, the processing module is specifically configured to:

[0040] Calculate the speed information of the moving target by formula (1);

[0041]

[0042] Wherein, v represents the relative radial motion speed between the moving target and the laser radar, f is the center frequency of the transmitted signal, c is the speed of light, fb+ ​​represents the frequency difference of the first half of the sweep cycle, and fb- represents the frequency difference of the second half of the sweep cycle.

[0043] Furthermore, the processing module is specifically configured to:

[0044] When fb+ is less than fb-, v is a positive value, and determining the velocity information of the moving target relative to the laser radar includes: the moving target moves toward the laser radar; or

[0045] When the fb+ is greater than the fb-, v is a negative value, and determining the speed information of the moving target relative to the laser radar includes: the moving target moves away from the laser radar.

[0046] Furthermore, the processing module is further configured to:

[0047] The distance of the moving target relative to the laser radar is determined based on the frequency values ​​of the two spectrum peaks in the spectrum data corresponding to the second difference frequency signal.

[0048] A third aspect of the embodiments of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the above method are implemented.

[0049] Compared with the prior art, the embodiments of the present application have the following advantages: by making the duration ratios of the difference frequency signals corresponding to the upper and lower sweep frequency bands used for Fourier transform in a single sweep frequency cycle inconsistent, a corresponding relationship between the spectrum amplitude and the spectrum of the difference frequency signals of the upper and lower sweep frequency bands is established, and the speed information between the target and the radar can be obtained by measuring the frequency difference between the upper and lower sweep frequency bands. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 A flowchart of a method for detecting target motion direction based on a frequency modulated continuous wave laser radar provided in one embodiment of the present application;

[0051] Figure 2 This is a time-frequency curve diagram of a radar signal modulated by a triangle wave when the target moves in one embodiment of the present application;

[0052] Figure 3 This is a spectrum diagram of the upper and lower frequency bands when the target moves away from the radar in one embodiment of the present application;

[0053] Figure 4 This is a spectrum diagram of the upper and lower frequency bands when the target moves towards the radar in one embodiment of the present application;

[0054] Figure 5 In another embodiment of the present application, a spectrum diagram of the upper and lower frequency bands when a target moves toward the radar;

[0055] Figure 6 In another embodiment of the present application, the spectrum diagram of the upper and lower frequency bands when the target moves away from the radar;

[0056] Figure 7 An embodiment of the present application provides a target motion direction detection device based on a frequency modulated continuous wave laser radar. DETAILED DESCRIPTION

[0057] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, this application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0058] The present application provides a flow chart of a method for detecting the target motion direction based on a frequency modulated continuous wave laser radar, see Figure 1 , the detection method comprises the following steps:

[0059] S1. Obtain a first difference frequency signal generated by mixing a transmitting signal and an echo signal within a single frequency sweep period T, wherein the transmitting signal is a signal transmitted by a frequency modulated continuous wave lidar based on triangular wave modulation, and the echo signal is an echo signal after the transmitting signal is reflected by a moving target.

[0060] Among them, no matter whether the moving target moves away from the radar or towards the radar, there will inevitably be a frequency difference between the transmitted signal and the echo signal. Therefore, the difference frequency signal obtained after mixing can reflect the Doppler frequency shift of the moving target echo signal.

[0061] S2, set the difference frequency signal data of a certain length t within half the frequency sweep period of the first difference frequency signal to zero to obtain a second difference frequency signal, where 0 <t<T / 2。

[0062] In step S2, the selected difference frequency signal of a certain duration t must be set to zero in the first half of the frequency sweep cycle, that is, the upper frequency sweep band, or the second half of the frequency sweep cycle, that is, the lower frequency sweep band. The difference frequency signal data cannot be set to zero in any half of the frequency sweep cycle. After obtaining the second difference frequency signal, it is necessary to perform a Fourier transform on the second difference frequency signal to obtain the spectrum data of the second difference frequency signal.

[0063] For the spectrum data of the second difference frequency signal, the two spectrum peaks with the largest amplitude values ​​are respectively determined as the first spectrum peak and the second spectrum peak, the spectrum peak with the larger amplitude value is defined as the first spectrum peak, and the spectrum peak with the smaller amplitude value is defined as the second spectrum peak, and the frequency value f1 of the first spectrum peak and the frequency value f2 of the second spectrum peak are respectively obtained.

[0064] In step S2, if the difference frequency signal of a certain duration t within the up-scanning frequency band is selected to be set to zero, the second spectrum peak frequency value f2 is regarded as the frequency difference fb+ of the up-scanning frequency band, and the first spectrum peak frequency f1 is regarded as the frequency difference fb- of the down-scanning frequency band; if the difference frequency signal of a certain duration t within the down-scanning frequency band is selected to be set to zero, the first spectrum peak frequency value f1 is regarded as the frequency difference fb+ of the up-scanning frequency band, and the second spectrum peak frequency f2 is regarded as the frequency difference fb- of the down-scanning frequency band.

[0065] S3. Determine the speed information of the moving target relative to the laser radar based on the frequency values ​​of the two spectrum peaks in the spectrum data corresponding to the second difference frequency signal, where the speed information includes the speed magnitude and direction.

[0066] In step S3, since the frequency difference fb+ of the up-sweep frequency band and the frequency difference fb- of the down-sweep frequency band are obtained from step S2, and there is relative motion between the moving target and the radar, as shown in FIG. Figure 2 As shown, taking the target moving toward the radar (approaching) as an example, the time-frequency curve of the transmitted signal of the FMCW lidar system using triangular wave modulation is as follows: Figure 2As shown in curve (a), the time-frequency curve of the echo signal when the moving target approaches is as follows Figure 2 As shown in curve (b), the time-frequency curve of the echo signal when the moving target is stationary is as follows Figure 2 As shown in curve (c), the corresponding time-frequency curve of the difference frequency signal is as follows Figure 2 As shown in the curve (d), T is the sweep period, ΔF is the sweep bandwidth, and τ is the time from signal transmission to reception. According to the Doppler shift principle, the Doppler shift f is the center frequency of the transmitted signal, and the frequency difference of the up-sweep frequency band is f b+ =f0-f d , the frequency difference of the down-sweep frequency band f b- =f0+f d , where f0 is the frequency of the difference signal when the target is stationary relative to the radar. From the above, we can get the speed information of the moving target Wherein v represents the relative radial motion speed between the moving target and the laser radar, and c is the speed of light.

[0067] Due to the Doppler effect, when the target moves toward the radar, the transmitted electromagnetic waves are compressed, the frequency increases, the echo signal frequency is greater than the transmitted signal frequency, and the Doppler shift is positive; when the target moves away from the radar, the transmitted electromagnetic waves are stretched, the frequency decreases, the echo signal frequency is less than the transmitted signal frequency, and the Doppler shift is negative.

[0068] If the target and radar are relatively stationary, the frequency difference between the upsweep band and the downsweep band is equal. If the target and radar are in relative motion, the received echo signal contains a Doppler shift, fd. The frequency difference between the upsweep band and the downsweep band differs, and velocity information (including velocity direction) can be calculated from these two frequency differences. Therefore, when fb+ is less than fb-, v is positive, indicating the target is moving toward the lidar. When fb+ is greater than fb-, v is negative, indicating the target is moving away from the lidar. When fb+ equals fb-, v is zero, indicating the target is stationary relative to the lidar.

[0069] Based on the above data, the distance R of the moving target relative to the laser radar can also be calculated. The calculation formula is as follows: Where T is the sweep period and ΔF is the sweep bandwidth.

[0070] The following examples further illustrate the target motion direction detection method based on frequency modulated continuous wave laser radar provided by this application.

[0071] Example 1

[0072] In Embodiment 1, for the method for detecting the moving direction of a target based on a frequency-modulated continuous-wave lidar provided above, in step S2, the difference frequency signal in a period t in the upward scanning frequency band is selected to be set to zero, and the obtained second difference frequency signal is as Figure 3 or Figure 4 shown. Combining Figure 3 and Figure 4 it can be seen that the amplitude values of the two spectral peaks are P1 and P2 respectively, where P1 > P2. Therefore, the spectral peak corresponding to P1 is the first spectral peak, the spectral peak corresponding to P2 is the second spectral peak, the frequency value of the first spectral peak is f1, and the frequency value of the second spectral peak is f2. Since the difference frequency signal in a period t in the upward scanning frequency band is selected to be set to zero, f2 is the frequency difference fb+ in the first half of the scanning period, and f1 is the frequency difference fb- in the second half of the scanning period.

[0073] For Figure 3 the difference frequency signal spectrum data in, f1 < f2. Therefore, according to the formula for the speed information of the moving target the value of v is negative, and the moving target moves away from the radar.

[0074] For Figure 4 the difference frequency signal spectrum data in, f1 > f2. Therefore, according to the formula for the speed information of the moving target the value of v is positive, and the moving target moves towards the radar.

[0075] Embodiment 2

[0076] In Embodiment 2, for the method for detecting the moving direction of a target based on a frequency-modulated continuous-wave lidar provided above, in step S2, the difference frequency signal in a period t in the downward scanning frequency band is selected to be set to zero, and the obtained second difference frequency signal is as Figure 5 or Figure 6 shown. Combining Figure 5 and Figure 6 it can be seen that the amplitude values of the two spectral peaks are P1 and P2 respectively, where P1 > P2. Therefore, the spectral peak corresponding to P is the first spectral peak, the spectral peak corresponding to P2 is the second spectral peak, the frequency value of the first spectral peak is f1, and the frequency value of the second spectral peak is f2. Since the difference frequency signal in a period t in the downward scanning frequency band is selected to be set to zero, f1 is the frequency difference fb+ in the first half of the scanning period, and f2 is the frequency difference fb- in the second half of the scanning period.

[0077] For Figure 5 the difference frequency signal spectrum data in, f1 < f2. Therefore, according to the formula for the speed information of the moving target the value of v is positive, and the moving target moves towards the radar.

[0078] For Figure 6For the difference frequency signal spectrum data, f1>f2, so according to the moving target speed information formula If the value of v is negative, the moving target moves away from the radar.

[0079] It should be noted that in Figures 3 to 6 In the process, invalid spectrum peaks caused by interference factors such as noise are removed, and the amplitude values ​​of invalid spectrum peaks caused by interference factors such as noise are also much smaller than the first spectrum peak and the second spectrum peak.

[0080] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0081] Example 3

[0082] like Figure 7 As shown, this embodiment provides a target motion direction detection device based on a frequency modulated continuous wave laser radar, including an acquisition module and a processing module. The acquisition module is connected to the frequency modulated continuous wave laser radar and is used to obtain a first difference frequency signal generated by mixing a transmitting signal and an echo signal of the laser radar within a single sweep period T. The transmitting signal is a signal transmitted by the frequency modulated continuous wave laser radar based on triangular wave modulation, and the echo signal is an echo signal after the transmitting signal is reflected by a moving target.

[0083] The processing module includes the following modules: a zero setting module, a spectrum peak acquisition module, and a velocity information calculation module.

[0084] The zeroing module is used to set the difference frequency signal data of a certain time length t within half the frequency sweep period of the first difference frequency signal to zero to obtain a second difference frequency signal, wherein 0 <t<T / 2;

[0085] The spectrum peak acquisition module is used to obtain two valid spectrum peaks in the spectrum data corresponding to the second difference frequency signal, determine the two spectrum peaks with the largest amplitude values ​​in the spectrum data corresponding to the second difference frequency signal as valid spectrum peaks, namely the first spectrum peak and the second spectrum peak, the amplitude value of the first spectrum peak is greater than the amplitude value of the second spectrum peak, and calculate the frequency values ​​of the two valid spectrum peaks.

[0086] The speed information calculation module is used to calculate the speed of the moving target relative to the laser radar according to the following method:

[0087] When the difference frequency signal data of a certain duration t within the first half of the frequency sweep period of the difference frequency signal is set to 0, the frequency value f2 of the second spectrum peak is determined as the frequency difference value fb+ of the first half of the frequency sweep period, and the frequency value f1 of the first spectrum peak is determined as the frequency difference value fb- of the second half of the frequency sweep period; or

[0088] When the difference frequency signal data of a certain duration t in the second half of the frequency sweep cycle of the difference frequency signal is set to 0, the frequency value f1 corresponding to the first spectrum peak is determined as the frequency difference fb+ of the first half of the frequency sweep cycle, and the frequency value f2 corresponding to the second spectrum peak is determined as the frequency difference fb- of the second half of the frequency sweep cycle; then according to the formula Calculate the speed of the moving target relative to the laser radar. And use the formula Calculate the distance of the moving target relative to the laser radar, where R represents the distance of the moving target relative to the laser radar, T is the sweep period, and ΔF is the sweep bandwidth.

[0089] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. A method for detecting target motion direction based on frequency modulated continuous wave laser radar, characterized in that: The method comprises: Acquire a first difference frequency signal generated by mixing a transmission signal and an echo signal within a single frequency sweep period T, wherein the transmission signal is a signal transmitted by a frequency modulated continuous wave lidar based on triangular wave modulation, and the echo signal is an echo signal after the transmission signal is reflected by a moving target; The difference frequency signal data of a certain time length t within half the frequency sweep period of the first difference frequency signal is set to zero to obtain a second difference frequency signal, wherein, 0 <t<T / 2; In the spectrum data corresponding to the second difference frequency signal, two spectrum peaks with the largest amplitude values ​​are determined as a first spectrum peak and a second spectrum peak, and the amplitude value of the first spectrum peak is greater than the amplitude value of the second spectrum peak; determining a frequency value of the first spectrum peak and a frequency value of the second spectrum peak; When the difference frequency signal data of a certain duration t within the first half of the frequency sweep cycle of the difference frequency signal is set to 0, the frequency value f2 of the second spectrum peak is determined as the frequency difference value fb+ of the first half of the frequency sweep cycle, and the frequency value f1 of the first spectrum peak is determined as the frequency difference value fb- of the second half of the frequency sweep cycle; or, when the difference frequency signal data of a certain duration t within the second half of the frequency sweep cycle of the difference frequency signal is set to 0, the frequency value f1 corresponding to the first spectrum peak is determined as the frequency difference value fb+ of the first half of the frequency sweep cycle, and the frequency value f2 corresponding to the second spectrum peak is determined as the frequency difference value fb- of the second half of the frequency sweep cycle; The speed information of the moving target relative to the laser radar is determined according to the frequency values ​​of the two spectrum peaks in the spectrum data corresponding to the second difference frequency signal, where the speed information includes the speed magnitude and direction.

2. The method according to claim 1, wherein The step of setting the difference frequency signal data of a duration of t within half a frequency sweep period of the first difference frequency signal to zero to obtain a second difference frequency signal includes: Setting the difference frequency signal data of a certain duration t within the first half of the frequency sweep period of the difference frequency signal to zero to obtain the second difference frequency signal; or The difference frequency signal data of a certain duration t within the second half of the frequency sweep period of the difference frequency signal is set to zero to obtain the second difference frequency signal.

3. The method according to claim 1 or 2, wherein: After obtaining the second difference frequency signal, the method further includes: Performing Fourier transform on the second difference frequency signal to obtain frequency spectrum data corresponding to the second difference frequency signal.

4. The method according to claim 1, wherein Determining the speed information of the moving target relative to the laser radar based on the frequency values ​​of two spectrum peaks in the spectrum data corresponding to the second difference frequency signal includes: Calculate the speed information of the moving target by formula (1); Wherein, v represents the relative radial motion speed between the moving target and the laser radar, f is the center frequency of the transmitted signal, c is the speed of light, fb+ ​​represents the frequency difference of the first half of the sweep cycle, and fb- represents the frequency difference of the second half of the sweep cycle.

5. The method according to claim 4, wherein Determining the speed information of the moving target relative to the laser radar according to the frequency values ​​of two spectrum peaks in the spectrum data corresponding to the second difference frequency signal includes: When fb+ is less than fb-, v is a positive value, and determining the velocity information of the moving target relative to the laser radar includes: the moving target moves toward the laser radar; or When the fb+ is greater than the fb-, v is a negative value, and determining the velocity information of the moving target relative to the laser radar includes: the moving target moves away from the laser radar; or When the fb+ is equal to the fb-, v is zero, and determining the speed information of the moving target relative to the laser radar includes: the moving target is stationary relative to the laser radar.

6. A target motion direction detection device based on frequency modulated continuous wave laser radar, characterized in that: Including acquisition module and processing module: The acquisition module is used to acquire a first difference frequency signal generated by mixing a transmission signal and an echo signal within a single frequency sweep period T, wherein the transmission signal is a signal transmitted by a frequency modulated continuous wave laser radar based on triangular wave modulation, and the echo signal is an echo signal after the transmission signal is reflected by a moving target; The processing module is used to set the difference frequency signal data of a certain duration t within half a frequency sweep period of the first difference frequency signal to zero to obtain a second difference frequency signal, wherein 0 <t<T / 2; The processing module is further configured to determine two spectrum peaks with the largest amplitude values ​​in the spectrum data corresponding to the second difference frequency signal as a first spectrum peak and a second spectrum peak, where the amplitude value of the first spectrum peak is greater than the amplitude value of the second spectrum peak, and determine frequency values ​​of the two spectrum peaks; When the difference frequency signal data of a certain duration t within the first half of the frequency sweep cycle of the difference frequency signal is set to 0, the frequency value f2 of the second spectrum peak is determined as the frequency difference value fb+ of the first half of the frequency sweep cycle, and the frequency value f1 of the first spectrum peak is determined as the frequency difference value fb- of the second half of the frequency sweep cycle; or, when the difference frequency signal data of a certain duration t within the second half of the frequency sweep cycle of the difference frequency signal is set to 0, the frequency value f1 corresponding to the first spectrum peak is determined as the frequency difference value fb+ of the first half of the frequency sweep cycle, and the frequency value f2 corresponding to the second spectrum peak is determined as the frequency difference value fb- of the second half of the frequency sweep cycle; The processing module is further used to determine the speed information of the moving target relative to the laser radar based on the frequency values ​​of two spectrum peaks in the spectrum data corresponding to the second difference frequency signal, where the speed information includes the speed magnitude and direction.

7. The device according to claim 6, characterized in that The processing module is specifically used to: Calculate the speed information of the moving target by formula (1); Wherein, v represents the relative radial motion speed between the moving target and the laser radar, f is the center frequency of the transmitted signal, c is the speed of light, fb+ ​​represents the frequency difference of the first half of the sweep cycle, and fb- represents the frequency difference of the second half of the sweep cycle.

8. The device according to claim 7, characterized in that The processing module is specifically used to: When fb+ is less than fb-, v is a positive value, and determining the velocity information of the moving target relative to the laser radar includes: the moving target moves toward the laser radar; or When the fb+ is greater than the fb-, v is a negative value, and determining the velocity information of the moving target relative to the laser radar includes: the moving target moves away from the laser radar; or When the fb+ is equal to the fb-, v is zero, and determining the speed information of the moving target relative to the laser radar includes: the moving target is stationary relative to the laser radar.

9. A computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the steps of the method according to any one of claims 1 to 5.

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