Detection method of lidar and lidar

Abstract

The present application provides a detection method and a lidar for a lidar, which relates to the technical field of lidar. The method includes: controlling a light source module to generate a first combined wave detection signal and a second combined wave detection signal; controlling the light source module to generate at least two first local oscillator signals and at least two second local oscillator signals; controlling a first photoelectric detection module to receive the first local oscillator signal, the second local oscillator signal, and a first combined wave echo signal, where the first combined wave echo signal is a signal formed by the first combined wave detection signal reflected by a target object; controlling a second photoelectric detection module to receive the first local oscillator signal, a second delayed local oscillator signal, and a second combined wave echo signal, where the second delayed local oscillator signal is a signal obtained by delaying the second local oscillator signal, and the second combined wave echo signal is a signal formed by the second combined wave detection signal reflected by the target object. This method can reduce the hardware cost of the lidar for realizing real-time speed measurement and ranging.

Description

Technical Field

[0001] The present application relates to the technical field of lidar, and more specifically, to a detection method and a lidar in the technical field of lidar. Background Art

[0002] Frequency Modulated Continuous Wave (FMCW) lidar adopts coherent detection technology. By emitting a laser with continuously modulated frequency to a target object, the signal light reflected by the target object interferes with the reference light, and the frequency of the beat signal generated by the interference is demodulated, so as to achieve high-precision and large-dynamic-range distance measurement. At the same time, the speed can be measured according to the magnitude of the speed beat frequency. Summary of the Invention

[0003] The present application provides a detection method and a lidar for a lidar, which can reduce the hardware cost of the lidar for realizing real-time speed measurement and ranging.

[0004] In a first aspect, a detection method for a lidar is provided. The method includes:

[0005] Controlling a light source module to generate a first combined wave detection signal and a second combined wave detection signal, so that the first combined wave detection signal and the second combined wave detection signal respectively detect a target object. Wherein, both the first combined wave detection signal and the second combined wave detection signal include a first detection signal and a second detection signal with different wavelengths. The first detection signal includes multiple first frequency sweep signals sequentially connected in the time domain, each first frequency sweep signal corresponds to a frequency sweep time zone, and the frequency sweep waveforms of two adjacent first frequency sweep signals in the time domain are non-collinear. The second detection signal includes multiple second frequency sweep signals sequentially connected in the time domain, each second frequency sweep signal corresponds to a frequency sweep time zone, and the frequency sweep waveforms of two adjacent second frequency sweep signals in the time domain are non-collinear. Each first frequency sweep signal corresponds to a second frequency sweep signal, and the frequency sweep directions of the first frequency sweep signal and the second frequency sweep signal corresponding to the same frequency sweep time zone are opposite;

[0006] Controlling the light source module to generate at least two first local oscillator signals and at least two second local oscillator signals, wherein the first local oscillator signal corresponds to the first detection signal, and the second local oscillator signal corresponds to the second detection signal;

[0007] Controlling a first photoelectric detection module to receive the first local oscillator signal, the second local oscillator signal and a first combined wave echo signal, where the first combined wave echo signal is a signal formed by the first combined wave detection signal reflected by the target object;

[0008] Control the second photoelectric detection module to receive the first local oscillator signal, the second delayed local oscillator signal, and the second combined wave echo signal, where the second delayed local oscillator signal is a signal obtained by delaying the second local oscillator signal, and the second combined wave echo signal is a signal formed by reflecting the second combined wave detection signal via the target object.

[0009] In a second aspect, a lidar is provided, including:

[0010] A light source module for generating a first combined wave detection signal and a second combined wave detection signal, so that the first combined wave detection signal and the second combined wave detection signal respectively detect a target object, where both the first combined wave detection signal and the second combined wave detection signal include a first detection signal and a second detection signal with different wavelengths. The first detection signal includes multiple segments of first swept-frequency signals sequentially connected in the time domain, each segment of the first swept-frequency signal corresponding to a swept-frequency time zone. The swept-frequency waveforms of two adjacent segments of the first swept-frequency signals in the time domain are non-collinear. The second detection signal includes multiple segments of second swept-frequency signals sequentially connected in the time domain, each segment of the second swept-frequency signal corresponding to a swept-frequency time zone. The swept-frequency waveforms of two adjacent segments of the second swept-frequency signals in the time domain are non-collinear. Each first swept-frequency signal corresponds to a second swept-frequency signal, and the swept-frequency directions of the first swept-frequency signal and the second swept-frequency signal corresponding to the same swept-frequency time zone are opposite;

[0011] The light source module is further configured to generate at least two beams of first local oscillator signals and at least two beams of second local oscillator signals, where the first local oscillator signal corresponds to the first detection signal, and the second local oscillator signal corresponds to the second detection signal;

[0012] A first photoelectric detection module for receiving the first local oscillator signal, the second local oscillator signal, and the first combined wave echo signal, where the first combined wave echo signal is a signal formed by reflecting the first combined wave detection signal via the target object;

[0013] A second photoelectric detection module for receiving the first local oscillator signal, the second delayed local oscillator signal, and the second combined wave echo signal, where the second delayed local oscillator signal is a signal obtained by delaying the second local oscillator signal, and the second combined wave echo signal is a signal formed by reflecting the second combined wave detection signal via the target object.

[0014] The beneficial effects brought by the technical solution provided by the embodiments of the present application at least include:

[0015] The embodiment of the present application provides a dual laser light source ranging and speed measurement process: by delaying the second local oscillator signal received by the second photoelectric detection module, the frequencies of the beat signals corresponding to the two signals are not symmetrical about the distance beat frequency, so the four frequencies corresponding to the two photoelectric detection modules can be used to determine which frequency corresponds to which wavelength of the light source, so as to be used for subsequent judgment of the speed direction. Thus, the first local oscillator signal, the second local oscillator signal and the first combined wave echo signal are beat in one photoelectric detection module, and the first local oscillator signal, the second delayed local oscillator signal and the second combined wave echo signal are beat in one photoelectric detection module, that is, only one set of photoelectric detection modules is used in each channel, without the need to use multiple sets of photoelectric detection modules, thereby reducing the cost of the laser radar ranging system. Thus, the purpose of achieving real-time ranging and speed measurement while taking into account the reduction of ranging costs is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a dual laser light source ranging principle diagram provided in an embodiment of the present application;

[0017] Figure 2 is a schematic flow chart of a laser radar detection method provided in an embodiment of the present application;

[0018] Figure 3 is a schematic diagram of a first detection signal and a second detection signal provided in an embodiment of the present application;

[0019] Figure 4 is a schematic flow chart of another laser radar detection method provided in an embodiment of the present application;

[0020] Figure 5 is a schematic diagram of a first beat frequency signal and a second beat frequency signal;

[0021] Figure 6 is a spectrum diagram of a beat frequency signal during an up-chirp provided in an embodiment of the present application;

[0022] Figure 7 is a schematic diagram of a third beat frequency signal and a fourth beat frequency signal;

[0023] Figure 8 is a spectrum diagram of a beat frequency signal provided in an embodiment of the present application;

[0024] Figure 9 is a schematic diagram of the structure of a laser radar device provided in an embodiment of the present application;

[0025] Figure 10 It is a structural schematic diagram of a laser radar provided in an embodiment of the present application. DETAILED DESCRIPTION

[0026] The technical solutions in the present application will be clearly and elaborately described below in conjunction with the accompanying drawings. Among them, in the description of the embodiments of the present application, unless otherwise specified, " / " means "or". For example, A / B may represent A or B. The "and / or" in the text is merely a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of the present application, "a plurality" means two or more than two.

[0027] Hereinafter, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as implying or suggesting relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features.

[0028] Frequency Modulated Continuous Wave (FMCW) lidar uses coherent detection technology. By emitting a laser with continuously modulated frequency towards the target object, the signal light reflected by the target object interferes with the reference light, and the frequency of the beat signal generated by the interference is demodulated, then high-precision and large-dynamic-range distance measurement can be achieved, and at the same time, the speed can be measured in real time according to the magnitude of the speed beat frequency.

[0029] Conventional lidar ranging systems use a single laser light source (i.e., Method 1) for detection. In order to measure the speed of a moving target object in real time, the lidar ranging system usually modulates the frequency of the light source in the form of a triangular wave sweep. The continuous wave obtained in this way has a frequency that increases with time in the first half cycle of a single complete period (which can also be called up-chirp), and the frequency decreases with time in the second half cycle (which can also be called down-chirp). When the target object has relative motion with respect to the lidar, the frequency of the beat signal includes the speed beat frequency generated by the Doppler effect. This speed beat frequency can be used for speed measurement, and the speed beat frequency generated by the Doppler effect during up-chirp is opposite to that during down-chirp. Therefore, by summing the beat frequencies of the beat signals during up-chirp and down-chirp, the influence of the Doppler frequency shift effect can be eliminated, and the frequency component representing only the distance can be further obtained. Correspondingly, by taking the difference or the absolute value of the difference of the beat frequencies of the beat signals during up-chirp and down-chirp, the distance frequency component can be eliminated, and the speed beat frequency representing the speed can be further obtained.

[0030] However, adopting Method 1 requires FMCW to go through a complete modulation cycle (including up-chirp and down-chirp) to eliminate the coupling between distance and speed and obtain the distance and speed information of the target object. The frequency modulation period is usually dozens of microseconds, which has a great impact on the ranging and speed measurement accuracy and efficiency of the lidar ranging system.

[0031] Aiming at the defects of the single laser light source (Method 1), the dual-laser light source ranging technology (Method 2) is proposed. Both light sources are modulated in the form of triangular wave frequency sweep to obtain the first modulated light and the second modulated light respectively. The up-chirp of the first modulated light corresponds to the down-chirp of the second modulated light, and the down-chirp of the first modulated light corresponds to the up-chirp of the second modulated light. The two light sources independently emit laser light to the target object and obtain independent beat frequency signals, so that the beat frequencies of the beat frequency signals during the up-chirp period of the first modulated light and the down-chirp period of the second modulated light, or the beat frequencies of the beat frequency signals during the down-chirp period of the first modulated light and the up-chirp period of the second modulated light can be obtained simultaneously. Therefore, at each moment, the coupling between distance and speed can be eliminated by the positive and negative frequency modulation slopes of the two light sources, and then the distance and speed of the target object can be obtained in real time.

[0032] However, in the lidar ranging system with dual laser light sources adopted in Method 2, usually 2 balanced photodetectors (BPD) are required for the echo signal reception of a single channel. Each BPD is used to receive the detection light and the local oscillator light corresponding to one light source; subsequent hardware circuits such as a trans-impedance amplifier (TIA) and an analog-to-digital converter (ADC) are required for each BPD. Therefore, the price for being able to decouple the speed and distance of the target object in real time in Method 2 is the doubling of the hardware circuit resources, resulting in an increase in the cost of the lidar ranging system.

[0033] To solve the problem of the increase in the overall cost in Method 2, this application provides an improved dual-laser light source ranging method, as Figure 1 shown, which is the ranging principle diagram of a lidar based on dual laser light sources provided by an embodiment of this application. In Figure 1 , taking 2 transceiver channels as an example here. The first light source and the second light source both obtain the first modulated light and the second modulated light respectively through triangular wave modulation. The up-chirp of the first modulated light corresponds to the down-chirp of the second modulated light, and the down-chirp of the first modulated light corresponds to the up-chirp of the second modulated light. The magnitude of the frequency modulation slope of the two signal lights is K fAfter the first light source passes through the first optical splitter, a part of it serves as the local oscillator light and a part serves as the detection light. After the second light source passes through the second optical splitter, a part of it serves as the local oscillator light and a part serves as the detection light. Among them, the local oscillator lights flowing from the first light source and the second light source to the illustrated channel 1 are combined by the first optical combiner, and then flow to the photoelectric detection module of channel 1 to perform coherent beat frequency with the corresponding return light; the local oscillator light flowing from the second light source to channel 2 passes through an additional delay line with a delay amount of τ, and then is combined with the local oscillator light flowing from the first light source to channel 2 by the second optical combiner, and then flows to the photoelectric detection module of channel 2 to perform coherent beat frequency with the corresponding return light. The detection lights of the first light source and the second light source respectively pass through their corresponding first optical amplifier and second optical amplifier to increase the emission power to enhance the ranging ability, and then pass through the third optical combiner and propagate in the same optical path to detect the target object. By splitting the combined detection light with a beam splitter, the signal transmission of multiple channels can be realized; for example, a 1×2 beam splitter can be used to realize the transceiver function of 2 channels.

[0034] Due to the polarization selection characteristics of the polarization beam splitter, the detection light beam with a specific polarization state 1 (such as the transverse electric mode polarization state) will exit from the Port2 port after entering from the Port1 port of the polarization beam splitter, and will become a collimated beam after passing through a quarter-wave plate and a lens system in sequence, and then be emitted to the target object in the area to be measured after passing through the scanning system; the target object reflects the detection light beam to form a return light beam, and the return light beam passes through the scanning system, the lens system and the quarter-wave plate in sequence. Since the light beam passes through the quarter-wave plate twice, the polarization state of the return light beam will rotate to polarization state 2 (such as the transverse magnetic mode polarization state), so it will exit from the Port3 port after entering from the Port2 port of the polarization beam splitter. The photoelectric detection module receives the combined local oscillator light and the corresponding return light beam above. The combined local oscillator light and the return light beam are mixed in the mixer, and the mixed signal flows to the BPD for photoelectric conversion to obtain the corresponding electrical signal, and further through the subsequent transimpedance amplifier (TIA), analog-to-digital converter (ADC) and Fourier transform (FFT), information such as the beat frequency of the signal can be obtained, so as to obtain the distance and speed of the target object.

[0035] Adopt Figure 1 The ranging principle of the double laser light source shown enables the return lights of the 2-way light sources to perform coherent beat frequency with their respective corresponding local oscillator lights on the same BPD, and at the same time applies an additional delay amount to the local oscillator signal of one of the light sources, so that when performing coherent beat frequency on the same BPD, the laser light sources corresponding to the 2 beat frequency signals can be distinguished, which is used to determine the direction of the target object's movement speed. Through the improvement of the ranging principle, only 1 BPD needs to be adopted for a single channel, which can save subsequent hardware circuits such as TIA and ADC while reducing the BPD, thereby reducing the cost of the lidar ranging system.

[0036] In applications, the detection method of the lidar provided by the embodiments of the present application can not only be applicable to quickly, efficiently, and accurately measure the distance and speed of a nearby target object, but also be applicable to quickly, efficiently, and accurately measure the distance and speed of a distant target object. It can be applied to any field that requires distance and speed measurement, such as intelligent transportation, aerospace, resource exploration, urban planning, agricultural development, water conservancy projects, land use, environmental monitoring, metallurgical manufacturing, textile manufacturing, etc. Specifically, it can be applied to driverless vehicles, unmanned aerial vehicles, robots, positioning systems, navigation systems, loading and unloading and handling equipment, metallurgical process control equipment, non-contact measurement equipment, etc.

[0037] In applications, the execution subject of the detection method of the lidar provided by the embodiments of the present application can be a lidar, specifically, the control and processing unit inside the lidar, or the SOC chip inside the lidar; it can also be a computer device communicatively connected to the lidar, and the above computer device can be a device such as a tablet, a radar-assisted computer, a vehicle-mounted terminal, or a mobile terminal. The following takes the lidar as the execution subject for illustration:

[0038] Figure 2 is a schematic flowchart of a detection method of a lidar provided by the embodiments of the present application. Exemplarily, as Figure 2 shown, the method 200 includes:

[0039] Step 201, control the light source module to generate a first combined wave detection signal and a second combined wave detection signal, so that the first combined wave detection signal and the second combined wave detection signal respectively detect the target object.

[0040] Among them, the light source module is a device in the lidar that can generate a laser detection signal. For a lidar with a dual-laser light source ranging principle, the light source module at least includes two light sources for generating signals with different wavelengths, such as the first light source and the second light source mentioned above; by configuring a combiner, a combined wave detection signal that combines the detection signals generated by the two light sources can be realized, and the number of combined wave detection signals finally output by the light source can include two beams, namely the first combined wave detection signal and the second combined wave detection signal.

[0041] Specifically, the process of generating the first multiplexed detection signal and the second multiplexed detection signal can be as follows: The first detection signal is generated by the first light source, and the second detection signal is generated by the second light source. The wavelengths of the first detection signal and the second detection signal are different. The first detection signal and the second detection signal are multiplexed by a multiplexer to obtain an initial multiplexed detection signal, and then the initial multiplexed detection signal is split by a beam splitter to obtain the first multiplexed detection signal and the second multiplexed detection signal. It should be noted that by multiplexing and then splitting, both the first multiplexed detection signal and the second multiplexed detection signal can include the first detection signal and the second detection signal with different wavelengths.

[0042] In other possible implementation manners, the light source module may include two first light sources and two second light sources. The first light source is used to generate the first detection signal, and the second light source is used to generate the second detection signal. The first detection signal generated by one of the first light sources and the second detection signal generated by one of the second light sources are multiplexed to obtain the first multiplexed detection signal, and the first detection signal generated by the other first light source and the second detection signal generated by the other second light source are multiplexed to obtain the second multiplexed detection signal. It can be understood that the present application does not specifically limit the specific composition of the light source module, as long as it can finally output the first multiplexed detection signal and the second multiplexed detection signal that both include the first detection signal and the second detection signal with different wavelengths.

[0043] When applying the dual-laser light source ranging principle for ranging and speed measurement, at each moment, the positive and negative frequency modulation slopes of the two light sources need to be used to eliminate the coupling of distance and speed. Correspondingly, when generating the first detection signal and the second detection signal, the frequency sweep directions of the first detection signal and the second detection signal are limited. That is, the first detection signal includes multiple first frequency sweep signals sequentially connected in the time domain. Each first frequency sweep signal corresponds to a frequency sweep time zone, and the frequency sweep waveforms of two adjacent first frequency sweep signals in the time domain are not collinear. The second detection signal includes multiple second frequency sweep signals sequentially connected in the time domain. Each second frequency sweep signal corresponds to a frequency sweep time zone, and the frequency sweep waveforms of two adjacent second frequency sweep signals in the time domain are not collinear. Each first frequency sweep signal corresponds to a second frequency sweep signal, and the frequency sweep directions of the first frequency sweep signal and the second frequency sweep signal corresponding to the same frequency sweep time zone are opposite. It should be noted that the "frequency sweep waveform" described in this application document means the frequency modulation waveform of the signal, that is, the graph of the signal's frequency changing with time, that is, the time-frequency diagram. The "frequency sweep waveforms of two frequency sweep signals are not collinear" described in this application document means that the time-frequency diagrams of the two frequency sweep signals are not on the same straight line. For example, the frequency sweep waveforms of two first frequency sweep signals can be parallel, that is, a sawtooth wave frequency sweep signal is formed; or for another example, the frequency sweep waveforms of two first frequency sweep signals can be mirror images, that is, a triangular wave frequency sweep signal is formed.

[0044] Exemplarily, the first detection signal and the second detection signal may be triangular wave swept-frequency signals after being modulated by a triangular wave. Alternatively, the first detection signal and the second detection signal may also be sawtooth wave swept-frequency signals. Figure 3 is a schematic diagram of the first detection signal and the second detection signal provided by an embodiment of the present application. As Figure 3 shown in (a) therein, the first detection signal 301 and the second detection signal 302 are triangular wave swept-frequency signals. In the same swept-frequency time zone, the swept-frequency direction of the first swept-frequency signal in the first detection signal 301 is opposite to the swept-frequency direction of the second swept-frequency signal in the second detection signal 302. For example, in the swept-frequency time zone 1, the swept-frequency direction of the first swept-frequency signal in the first detection signal 301 is upward swept-frequency, and the swept-frequency direction of the second swept-frequency signal in the second detection signal 302 is downward swept-frequency; in the swept-frequency time zone 2, the swept-frequency direction of the first swept-frequency signal in the first detection signal 301 is downward swept-frequency, and the swept-frequency direction of the second swept-frequency signal in the second detection signal 302 is upward swept-frequency. Moreover, the swept-frequency waveforms of two adjacent segments of the first swept-frequency signal (or two adjacent segments of the second swept-frequency signal) in the time domain are not collinear.

[0045] As Figure 3 shown in (b) therein, the first detection signal 303 and the second detection signal 304 are sawtooth wave swept-frequency signals. In the swept-frequency time zone 3, the swept-frequency direction of the first swept-frequency signal in the first detection signal 303 is upward swept-frequency, and the swept-frequency direction of the second swept-frequency signal in the second detection signal 304 is downward swept-frequency. Moreover, the swept-frequency waveforms of two adjacent segments of the first swept-frequency signal (or two adjacent segments of the second swept-frequency signal) in the time domain are not collinear.

[0046] In the actual ranging and speed measurement processes of the lidar, the lidar controls the light source module to generate a first combined wave detection signal and a second combined wave detection signal, and the first combined wave detection signal and the second combined wave detection signal are transmitted to the target object for detecting the target object.

[0047] Step 202, control the light source module to generate at least two first local oscillator signals and at least two second local oscillator signals, where the first local oscillator signal corresponds to the first detection signal, and the second local oscillator signal corresponds to the second detection signal.

[0048] When applying the dual-laser-source ranging principle for ranging and velocity measurement, in addition to generating a first combined-wave detection signal and a second combined-wave detection signal for detecting a target object, a local oscillator signal also needs to be generated for beating with the echo signals of the combined-wave detection signals to obtain a beat signal ultimately used for distance and velocity calculation. Considering that a first combined-wave detection signal and a second combined-wave detection signal are generated, and both the first combined-wave detection signal and the second combined-wave detection signal include a first detection signal and a second detection signal with different wavelengths, the lidar needs to control the light source module to generate at least two first local oscillator signals and at least two second local oscillator signals. The first local oscillator signal corresponds to the first detection signal, and the second local oscillator signal corresponds to the second detection signal.

[0049] When generating the first local oscillator signal and the second local oscillator signal, Method 1: The first local oscillator signal and the first detection signal are from the modulation signal output by the same first light source, and the second local oscillator signal and the second detection signal are from the modulation signal output by the same second light source. That is, the lidar controls the light source module to generate a first modulation signal, and the first modulation signal generated by the light source module is split by a beam splitter to obtain a first detection signal and a first local oscillator signal. Similarly, the lidar controls the light source module to generate a second modulation signal, and the second modulation signal generated by the light source module is split by a beam splitter to obtain a second detection signal and a second local oscillator signal. Method 2: The first local oscillator signal and the first detection signal are respectively output by different light sources, but the time-frequency characteristics of these two signals are the same; the second local oscillator signal and the second detection signal are respectively output by different light sources, but the time-frequency characteristics of these two signals are the same.

[0050] Combined with the generation process of the first combined-wave detection signal and the second combined-wave detection signal, if Method 1 is used to generate at least two first local oscillator signals and at least two second local oscillator signals, specifically, the process of generating the first combined-wave detection signal, the second combined-wave detection signal, the first local oscillator signal, and the second local oscillator signal can be as follows: Refer to Figure 1 , the first light source in the light source module generates a first modulation signal, and the first modulation signal is split by a first beam splitter to obtain a first detection signal and a first local oscillator signal. The first local oscillator signal is input into a first beam splitter to obtain at least two first local oscillator signals; the second light source in the light source module generates a second modulation signal, and the second modulation signal is split by a second beam splitter to obtain a second detection signal and a second local oscillator signal. The second local oscillator signal is input into a second beam splitter to obtain at least two second local oscillator signals; then, the first detection signal and the second detection signal are input into a third combiner, and the first detection signal and the second detection signal are combined by the third combiner to obtain a combined-wave detection signal, which is then input into a third beam splitter for splitting to obtain a first combined-wave detection signal and a second combined-wave detection signal.

[0051] Optionally, for the case where the light source module includes two first light sources and two second light sources, the process of generating the first combined wave detection signal, the second combined wave detection signal, the first local oscillator signal, and the second local oscillator signal can also be as follows: One of the first light sources and one of the second light sources in the light source module respectively generate a first modulation signal and a second modulation signal. The first splitter splits the first modulation signal to obtain a first detection signal and a first local oscillator signal. The second splitter splits the second modulation signal to obtain a second detection signal and a second local oscillator signal. The first combiner in the light source module combines the first detection signal and the second detection signal to generate a first combined wave detection signal. The other first light source and the second light source in the light source module respectively generate a first modulation signal and a second modulation signal. The third splitter splits the first modulation signal to obtain a first detection signal and a first local oscillator signal. The fourth splitter splits the second modulation signal to obtain a second detection signal and a second local oscillator signal. The second combiner in the light source module combines the first detection signal and the second detection signal to generate a second combined wave detection signal. Finally, a first combined wave detection signal, a second combined wave detection signal, two beams of first local oscillator signals, and two beams of second local oscillator signals are obtained.

[0052] Step 203: Control the first photoelectric detection module to receive the first local oscillator signal, the second local oscillator signal, and the first combined wave echo signal, where the first combined wave echo signal is a signal formed by the reflection of the first combined wave detection signal by the target object.

[0053] The photoelectric detection module is any device that can receive the local oscillator signal, as well as the echo signal formed by the reflection of the detection signal by the target object, and output the electrical signal corresponding to the beat signal of the local oscillator signal and the echo signal. For example, the photoelectric detection module may include a photodetector. During the process of receiving the above local oscillator signal and echo signal, the local oscillator signal and the echo signal are beat by means of free-space optical signal beating, and the photodetector performs photoelectric conversion on the beat signal to obtain an electrical signal related to the beat signal. For example, the photoelectric detection module may also include a mixer and a balanced photodetector. The mixer is used to receive the above local oscillator signal and echo signal to cause the local oscillator signal and the echo signal to beat inside it, and the balanced photodetector is used to perform balanced detection on the beat signal to obtain an electrical signal related to the beat signal.

[0054] When applying the principle of double laser source ranging for ranging and speed measurement, a lidar is equipped with a first photoelectric detection module and a second photoelectric detection module. The first photoelectric detection module is used to receive a first local oscillator signal, a second local oscillator signal, and a first combined wave echo signal formed by the reflection of a first combined wave detection signal by a target object. In the first photoelectric detection module, the first local oscillator signal, the second local oscillator signal, and the first combined wave echo signal are subjected to beat frequency to obtain two beat frequency signals. Specifically, the first combined wave echo signal includes a first echo signal formed by the reflection of a first detection signal by the target object and a second echo signal formed by the reflection of a second detection signal by the target object. The above-mentioned first local oscillator signal and the first echo signal are coherently beat, and the second local oscillator signal and the second echo signal are coherently beat.

[0055] Step 204, control the second photoelectric detection module to receive the first local oscillator signal, the second delayed local oscillator signal, and the second combined wave echo signal, where the second delayed local oscillator signal is a signal obtained by delaying the second local oscillator signal, and the second combined wave echo signal is a signal formed by the reflection of the second combined wave detection signal by the target object.

[0056] In order to be able to distinguish which wavelength of light source each of the two beat frequency signals corresponds to and to determine the movement direction of the target object, the second local oscillator signal received by the second photoelectric detection module is delayed so that the frequencies of the two beat frequency signals are not symmetric about the distance beat frequency, for distinguishing the light source corresponding to the beat frequency signal. Then, the delay module in the lidar delays at least one of the second local oscillator signals to obtain the second delayed local oscillator signal, so that the second photoelectric detection module receives the first local oscillator signal, the second delayed local oscillator signal, and the second combined wave echo signal formed by the reflection of the second combined wave detection signal by the target object, and performs beat frequency in the second photoelectric detection module to obtain two beat frequency signals. Specifically, the second combined wave echo signal includes a first echo signal formed by the reflection of a first detection signal by the target object and a second echo signal formed by the reflection of a second detection signal by the target object. The above-mentioned first local oscillator signal and the first echo signal are coherently beat, and the second delayed local oscillator signal and the second echo signal are coherently beat.

[0057] In summary, the embodiment of the present application provides a ranging and velocity measuring process for a dual-laser light source: by delaying the second local oscillator signal received by the second photoelectric detection module, the frequencies of the beat signals corresponding to the two signals are not symmetric about the distance beat frequency. Therefore, it is possible to determine which frequency corresponds to the light source of which wavelength through the four frequencies corresponding to the two photoelectric detection modules, for subsequent determination of the velocity direction. Thus, the first local oscillator signal, the second local oscillator signal, and the first combined wave echo signal are beat in one photoelectric detection module, and the first local oscillator signal, the second delayed local oscillator signal, and the second combined wave echo signal are beat in one photoelectric detection module, that is, only one set of photoelectric detection modules is used in each channel, without the need to use multiple sets of photoelectric detection modules, reducing the cost of the lidar ranging system.

[0058] Based on the above detection process of the lidar, the first photoelectric detection module can output the beat electrical signals corresponding to the two beat signals, and the second photoelectric detection module can output the beat electrical signals corresponding to the two beat signals. Photoelectric conversion does not change the frequency of the signal. Therefore, by calculating the frequency in the above beat electrical signals, the distance and velocity of the target object can be obtained. The following embodiments will mainly elaborate on the calculation process of the beat signal in detail.

[0059] Figure 4 It is a schematic flowchart of another detection method of the lidar provided by the embodiment of the present application. Exemplarily, as Figure 4 shown, the method 400 includes:

[0060] Step 401, obtain a first frequency and a second frequency corresponding to a first swept frequency time zone, where the first swept frequency time zone is one of the swept frequency time zones, and the first local oscillator signal, the second local oscillator signal, and the first combined wave echo signal are beat to obtain a first beat signal and a second beat signal. The first frequency and the second frequency are, in sequence, the higher one and the lower one of the frequencies of the first beat signal and the second beat signal.

[0061] At the first photoelectric detection module, the first local oscillator signal, the second local oscillator signal, and the first combined wave echo signal are beat to obtain a first beat signal and a second beat signal; specifically, the first local oscillator signal and the first echo signal in the first combined wave echo signal are beat to obtain the first beat signal, and the first echo signal is the echo signal formed by the first detection signal reflected by the target object. The second local oscillator signal and the second echo signal in the first combined wave echo signal are beat to obtain the second beat signal, and the second echo signal is the echo signal formed by the second detection signal reflected by the target object.

[0062] Exemplarily, Figure 5 are the schematic diagrams of the first beat signal and the second beat signal, shown here with the target object moving relatively away from the lidar as an example. AsFigure 5 As shown, the first local oscillation light and the first retroreflected light are beat-frequency mixed to obtain a first beat-frequency signal, and the second local oscillation light and the second retroreflected light are beat-frequency mixed to obtain a second beat-frequency signal. And the frequencies of the first beat-frequency signal and the second beat-frequency signal have the following corresponding relationship:

[0063] Δ f 1up = f R + f d

[0064] Δ f 2dn = f R - f d

[0065] Δ f 1dn = f R - f d

[0066] Δ f 2up = f R + f d

[0067] K f = B s / T s

[0068] Where, Δ f 1up is the beat frequency of the first beat-frequency signal when the first local oscillation signal is in the up-chirp period, Δ f 2dn is the beat frequency of the second beat-frequency signal when the first local oscillation signal is in the up-chirp period, Δ f 1dn is the beat frequency of the first beat-frequency signal when the first local oscillation signal is in the down-chirp period, Δ f 2up is the beat frequency of the second beat-frequency signal when the first local oscillation signal is in the down-chirp period; where, the up-chirp and down-chirp mentioned here respectively correspond to a sweep frequency time zone, and the first sweep frequency time zone can be any one of them. f R is the distance beat frequency, f d is the velocity beat frequency, K fis the sweep slope, B s is the signal bandwidth, T s is a sweep time zone. It should be noted that the above beat frequency is the frequency determined for the beat signal in the time interval with a constant frequency.

[0069] If the larger value of the frequency in the beat signal is defined as f L , and the smaller value is f S , for the beat signal obtained by the first photoelectric detection module, during the up-chirp period (up-sweep period), if the velocity beat frequency brought by the target object is negative, f L corresponds to Figure 5 the Δ shown in f 1up , f S corresponds to Figure 5 the Δ shown in f 2dn ; if the velocity beat frequency brought by the target object is positive, f L then it corresponds to Δ f 2dn , f S corresponds to Δ f 1up , exactly the opposite. Similarly, during the down-chirp period (down-sweep period), if the velocity beat frequency brought by the target object is negative, f L corresponds to Δ f 2up , f S corresponds to Δ f 1dn ; if the velocity beat frequency brought by the target object is positive, f L corresponds to Δ f 1dn , f S corresponds to Δ f 2up , exactly the opposite.

[0070] Figure 6 is the spectrogram of the beat signal during the up-chirp period provided by the embodiment of the present application. Figure 6 In (a) of Figure 6In (b), a spectrogram of the beat frequency signal in the scenario where the target object is close to the lidar during up-chirping is shown. In this scenario, the velocity beat frequency is positive, and the dashed line in the figure represents f R .

[0071] As can be seen from Figure 6 , in the beat frequency spectrum obtained based on the first beat frequency signal and the second beat frequency signal, the beat frequencies are symmetric about the distance beat frequency ( f R ). This makes it impossible to distinguish which wavelength of the detection signal (light source) each of the two beat frequency signals corresponds to when performing signal resolution based on the first beat frequency signal and the second beat frequency signal. Furthermore, it is impossible to know whether the larger value f L (or the smaller value f S ) corresponds to the first light source or the second light source in the light source module, and thus it is impossible to finally determine the velocity direction of the target object's movement. That is to say, the frequency values resolved based on the first beat frequency signal and the second beat frequency signal can only be used to determine the distance of the target object relative to the lidar and the magnitude of the radial velocity, but the velocity direction of the target object's movement cannot be obtained.

[0072] Correspondingly, when resolving the first beat frequency signal and the second beat frequency signal, by obtaining the first frequency and the second frequency of the first sweep time zone, which is one of the sweep time zones, the first frequency is the higher one of the beat frequencies of the first beat frequency signal and the second beat frequency signal, and the second frequency is the lower one of the frequencies of the first beat frequency signal and the second beat frequency signal.

[0073] Step 402, obtain a third frequency and a fourth frequency corresponding to the first sweep time zone. Among them, the first local oscillator signal, the second delayed local oscillator signal, and the second combined wave echo signal are beat to obtain a third beat frequency signal and a fourth beat frequency signal. The third frequency and the fourth frequency are successively the higher one and the lower one of the frequencies of the third beat frequency signal and the fourth beat frequency signal.

[0074] At the second photoelectric detection module, the first local oscillator signal, the second delayed local oscillator signal, and the second combined wave echo signal are beat to obtain a third beat frequency signal and a fourth beat frequency signal. Specifically, the first local oscillator signal and the first echo signal in the second combined wave echo signal are beat to obtain a third beat frequency signal. The first echo signal is the echo signal formed by the first detection signal reflected by the target object. The second delayed local oscillator signal and the second echo signal in the second combined wave echo signal are beat to obtain a fourth beat frequency signal. The second echo signal is the echo signal formed by the second detection signal reflected by the target object.

[0075] Exemplarily, Figure 7It is a schematic diagram of the third beat frequency signal and the fourth beat frequency signal, still taking the example where the target object is relatively far away from the lidar. As Figure 7 shown, the third beat frequency signal is obtained after the first local oscillator light and the first backscattered light are beat, and the fourth beat frequency signal is obtained after the second delayed local oscillator light and the second backscattered light are beat. Since the second local oscillator light introduces an additional delay amount, a f τ frequency shift is generated. Therefore, the frequencies of the two beat frequency signals finally obtained in the second photoelectric detection module are no longer symmetric about f R and have the following corresponding relationship:

[0076] Δ f 1up = f R + f d

[0077] Δ f 2dn = f R - f d - f τ

[0078] Δ f 1dn = f R - f d

[0079] Δ f 2up = f R + f d - f τ

[0080] K f = B s / T s

[0081] Among them, Δ f 1up is the beat frequency of the third beat frequency signal when the first local oscillator signal is in the up-chirp period, Δ f 2dn is the beat frequency of the fourth beat frequency signal when the first local oscillator signal is in the up-chirp period, Δ f 1dn is the beat frequency of the third beat frequency signal when the first local oscillator signal is in the down-chirp period, Δf 2up The beat frequency of the fourth beat frequency signal during the downward chirp of the first local oscillator signal. f R Is the distance beat frequency, f d Is the velocity beat frequency, f τ Is the delay frequency corresponding to the delay of the second local oscillator signal, K f Is the frequency sweep slope, B s Is the signal bandwidth, T s Is a frequency sweep time zone.

[0082] Figure 8 Is the spectrogram of the beat frequency signal provided by the embodiment of the present application. Exemplarily, as Figure 8 Shown in (a) of, it shows the frequency schematic diagram of the beat frequency signal in the scenario where the target object is far from the lidar during the upward chirp. In this scenario, the velocity beat frequency is negative. At this time, f L Corresponds to Figure 8 The Δ shown in f 1up , f S Corresponds to Figure 8 The Δ shown in f 2dn In the figure, the middle dashed line represents f R In the figure, the left dashed line represents Δ in the scenario where the second local oscillator signal is not delayed f 2dn Should be the frequency at which it is located. The frequency at this dashed line is mirrored with respect to Δ f 1up About f R Mirror image. The above Δ f 2dn Is then offset downward from this frequency by f τ .

[0083] Such as Figure 8 Shown in (b) of, it shows the spectrogram of the beat frequency signal in the scenario where the target object is close to the lidar during the upward chirp. In this scenario, the velocity beat frequency is positive. At this time, f L Then corresponds to Δ f 2dn , f S Corresponds to Δ f 1up In the figure, the middle dashed line representsf R , the dashed line on the right side in the figure represents Δ in the scenario where the second local oscillator signal is not delayed. f 2dn should be the frequency, and this frequency is related to Δ f 1up Regarding f R the mirror image, the above-mentioned Δ f 2dn is offset downward relative to this frequency f τ .

[0084] As Figure 8 shown in (c) of [], it shows the spectrogram of the beat frequency signal in the scenario where the target object is moving away from the lidar during the down-chirp. In this scenario, the velocity beat frequency is negative. At this time, f L corresponding to Δ f 2up , f S corresponding to Δ f 1dn , the dashed line in the middle of the figure represents f R , the dashed line on the right side in the figure represents Δ in the scenario where the second local oscillator signal is not delayed. f 2up should be the frequency, and this frequency is related to Δ f 1dn Regarding f R the mirror image, the above-mentioned Δ f 2up is offset downward relative to this frequency f τ .

[0085] As Figure 8 shown in (d) of [], it shows the spectrogram of the beat frequency signal in the scenario where the target object is approaching the lidar during the down-chirp. In this scenario, the velocity beat frequency is positive. At this time, f L corresponding to Δ f 1dn , f S corresponding to Δ f 2up , the dashed line in the middle of the figure represents f R , the dashed line on the left side in the figure represents Δ in the scenario where the second local oscillator signal is not delayed. f 2up should be the frequency, and this frequency is related to Δ f 1dn Regarding fR Mirror image, the above Δ f 2up Then it is offset downward relative to this frequency f τ 。

[0086] From Figure 7 and Figure 8 it can be known that for the speed of the target object, the frequency shift f τ brings the spectrum about f R of asymmetry to judge the positive and negative of the speed beat frequency, that is, the direction of the movement speed of the target object. Specifically, for the up-chirp frequency sweep time zone, the spectrograms corresponding to the target object approaching or moving away are different. Figure 8 In (a), the difference between the third frequency and the fourth frequency will be greater than twice the speed beat frequency. Figure 8 In (b), the difference between the third frequency and the fourth frequency will be less than twice the speed beat frequency. Then, based on this feature, it can be judged whether the target object is approaching or moving away from the lidar, that is, the speed direction of the lidar can be determined. The principle of down-chirp is basically the same and will not be elaborated here.

[0087] Correspondingly, when resolving the third beat signal and the fourth beat signal, by obtaining the third frequency and the fourth frequency of the first frequency sweep time zone, the first frequency sweep time zone is one of the frequency sweep time zones, the third frequency is the higher one of the frequency of the third beat signal and the frequency of the fourth beat signal, and the fourth frequency is the lower one of the frequency of the third beat signal and the frequency of the fourth beat signal.

[0088] Step 403, determine the distance and speed of the target object relative to the lidar according to the first frequency, the second frequency, the third frequency and the fourth frequency. After resolving the first frequency and the second frequency from the two beat signals output by the first photoelectric detection module, and resolving the third frequency and the fourth frequency from the two beat signals output by the second photoelectric detection module, the distance and speed of the target object relative to the lidar can be determined based on the first frequency, the second frequency, the third frequency and the fourth frequency.

[0089] Considering that the frequencies of the two beat signals output by the first optoelectronic detection module are symmetric about the distance beat frequency and it alone cannot distinguish which wavelength of detection signal (light source) each of the two beat signals corresponds to, the two frequency values calculated from the beat signals output by the first optoelectronic detection module can only be used to calculate the distance and speed magnitude of the target object relative to the lidar, but cannot calculate the speed direction. Since there is a time delay in the second local oscillator signal received by the second optoelectronic detection module, the asymmetry can be used to determine the speed direction. Therefore, by combining multiple frequencies of the beat signals output by the first optoelectronic detection module and the second optoelectronic detection module, the distance, speed magnitude, and speed direction of the lidar can be calculated.

[0090] In an exemplary example, step 403 may further include step 403A and step 403B.

[0091] Step 403A, determining the first distance and the magnitude of the first speed of the target object relative to the lidar according to the first frequency and the second frequency.

[0092] In a possible implementation, after the lidar obtains the first beat signal and the second beat signal, for each same sweep time zone, the higher value of the frequencies - the first frequency, and the lower value of the frequencies - the second frequency in the first beat signal and the second beat signal are obtained, and a preset calculation formula is used to calculate in real time the first distance and the magnitude of the first speed of the target object relative to the lidar based on the first frequency and the second frequency.

[0093] Exemplarily, the calculation formulas for calculating the distance and speed based on the first frequency and the second frequency may be as shown in formulas (1) to (4).

[0094] f R = ( f L + f S ) / 2 (1)

[0095] f d = | f L - f S | / 2 (2)

[0096] R = c ·Δ t / 2 = c ·( f R / K f ) / 2 (3)

[0097] | ν | = λ · f d / 2(4)

[0098] Among them, f R represents the distance beat frequency, f d represents the velocity beat frequency, f L represents the larger value of the beat frequencies of two beat signals, f S represents the smaller value of the beat frequencies of two beat signals, c represents the speed of light, Δ t is the time, K f represents the sweep slope, R represents the distance of the target object, | ν | represents the magnitude of the velocity of the target object.

[0099] Then, based on the above formulas (1) to (4), the process of calculating the distance and velocity magnitude of the target object relative to the lidar according to the first frequency and the second frequency may further include steps 403A1 to 403A3.

[0100] Step 403A1: Determine the first distance beat frequency and the first velocity beat frequency corresponding to the first beat signal or the second beat signal according to the first frequency and the second frequency.

[0101] Step 403A2: Determine the first distance according to the first distance beat frequency.

[0102] Step 403A3: Determine the magnitude of the first velocity according to the first velocity beat frequency.

[0103] It can be seen from formulas (3) and (4) that if it is necessary to calculate the distance of the target object, it is necessary to first calculate the distance beat frequency, and if it is necessary to calculate the velocity of the target object, it is necessary to first calculate the velocity beat frequency of the target object. Correspondingly, according to the first frequency and the second frequency, substitute them into the calculation formulas (1) and (2) respectively to determine the first distance beat frequency and the first velocity beat frequency corresponding to the first beat signal or the second beat signal, and then substitute the calculated first distance beat frequency into the calculation formula (3) to determine the first distance of the target object relative to the lidar, and substitute the calculated first velocity beat frequency into the calculation formula (4) to determine the magnitude of the first velocity of the target object relative to the lidar.

[0104] Specifically, half of the sum value of the first frequency and the second frequency is determined as the first distance beat frequency, and half of the difference value of the first frequency and the second frequency is determined as the first velocity beat frequency; such that based on the first distance beat frequency, the sweep slope, and the speed of light, the distance of the target object relative to the lidar is determined, and based on the first velocity beat frequency and the wavelength, the magnitude of the first velocity of the target object relative to the lidar is determined.

[0105] Step 403B: Determine the velocity direction of the target object relative to the lidar according to the first frequency, the second frequency, the third frequency, and the fourth frequency.

[0106] It can be known from Figure 8 that if it is during the up-chirp period and the difference between the larger frequency value and the smaller frequency value is greater than twice the velocity beat frequency, it can be determined that the target object is moving away from the lidar; if it is during the up-chirp period and the difference between the larger frequency value and the smaller frequency value is less than twice the velocity beat frequency, then it can be determined that the target object is approaching the lidar. If it is during the down-chirp period and the difference between the larger frequency value and the smaller frequency value is greater than twice the velocity beat frequency, it can be determined that the target object is approaching the lidar; if it is during the down-chirp period and the difference between the larger frequency value and the smaller frequency value is less than twice the velocity beat frequency, it can be determined that the target object is moving away from the lidar. Then based on this correlation, when determining the velocity direction of the target object relative to the lidar, for each sweep time zone, the magnitude relationship between the difference between the larger frequency value and the smaller frequency value and the velocity beat frequency can be verified to determine the velocity direction of the target object relative to the lidar.

[0107] However, the velocity beat frequency cannot be calculated from only the beat frequencies of the two beat signals output by the second photodetection module. The velocity beat frequency needs to be calculated from the beat frequencies of the two beat signals output by the first photodetection module. Then in a possible implementation manner, after the lidar obtains the first beat signal, the second beat signal, the third beat signal, and the fourth beat signal, for each same sweep time zone, the higher value of the frequencies in the first beat signal and the second beat signal - the first frequency, and the lower value of the frequencies - the second frequency are obtained, the higher value of the frequencies in the third beat signal and the fourth beat signal - the third frequency, and the lower value of the frequencies - the fourth frequency are obtained, and a preset calculation formula is used to calculate in real time the velocity direction of the target object relative to the lidar based on the first frequency, the second frequency, the third frequency, and the fourth frequency.

[0108] Exemplarily, the process of determining the velocity direction of the target object relative to the lidar according to the first frequency, the second frequency, the third frequency, and the fourth frequency may further include step 403B1 and step 403B2.

[0109] Step 403B1: Determine the first velocity beat frequency corresponding to the first beat signal or the second beat signal according to the first frequency and the second frequency.

[0110] Step 403B2: Determine the velocity direction of the target object relative to the lidar according to the first velocity beat frequency, the third frequency, and the fourth frequency.

[0111] First, after obtaining the first frequency and the second frequency calculated from the first beat signal and the second beat signal, half of the difference between the first frequency and the second frequency is determined as the first velocity beat frequency of the first beat signal or the second beat signal, so as to subsequently calculate the velocity direction of the target object relative to the lidar in real time according to the first velocity beat frequency, in combination with the third frequency and the fourth frequency.

[0112] Specifically, when determining the velocity direction, it is necessary to first determine twice the first velocity beat frequency, as well as the difference between the third frequency and the fourth frequency, and then verify the magnitude relationship between the two to determine the velocity direction. Correspondingly, according to the difference between the third frequency and the fourth frequency, it is defined as the first verification value, and twice the first velocity beat frequency is defined as the second verification value. Then, according to the magnitude relationship between the first verification value and the second verification value in a specific beat direction, the velocity direction of the target object relative to the lidar is determined.

[0113] Since there are two sweep directions, namely the up-sweep and the down-sweep, and the mapping relationship between the magnitude relationship between the first verification value and the second verification value and the velocity direction is different for each sweep direction, the situation of determining the velocity direction of the target object relative to the lidar according to the magnitude relationship between the first verification value and the second verification value can include the following four situations:

[0114] Among them, the sweep direction of the first detection signal corresponding to the first sweep time zone is the up-sweep corresponding to situation (a) and situation (b).

[0115] Situation (a): If the first verification value is greater than the second verification value, it is determined that the target object is moving away from the lidar.

[0116] During the chirp of the first detection signal, that is, during the up-sweep, if | f L - f S | > 2 f d , then according to Figure 8 shown in (a) of f d = f L - f RThat is, the target object is far from the ranging system. Correspondingly, if the sweep direction is upward sweep and the first verification value (the difference between the third frequency and the fourth frequency) is greater than the second verification value (twice the first velocity beat frequency), it can be determined that the target object is far from the lidar.

[0117] Case (b): If the first verification value is less than the second verification value, it is determined that the target object is approaching the lidar.

[0118] During the chirping of the first detection signal, that is, during the upward sweep of the sweep direction, if | f L - f S |<2 f d , then according to Figure 8 shown in (b) of f d = f R - f S That is, the target object is approaching the ranging system. Correspondingly, if the sweep direction is upward sweep and the first verification value (the difference between the third frequency and the fourth frequency) is less than the second verification value (twice the first velocity beat frequency), it can be determined that the target object is approaching the lidar.

[0119] If the sweep direction of the first detection signal corresponding to the first sweep time zone is downward sweep, corresponding to case (c) and case (d).

[0120] Case (c): If the first verification value is less than the second verification value, it is determined that the target object is far from the lidar.

[0121] During the downward chirping of the first detection signal, that is, during the downward sweep of the sweep direction, if | f L - f R |<2 f d , then according to Figure 8 shown in (c) of f d = f R - f S That is, the target object is far from the ranging system. Correspondingly, if the sweep direction is downward sweep and the first verification value (the difference between the third frequency and the fourth frequency) is less than the second verification value (twice the first velocity beat frequency), it can be determined that the target object is far from the lidar.

[0122] Case (d): If the first verification value is greater than the second verification value, it is determined that the target object is approaching the lidar.

[0123] During the chirping under the first detection signal, that is, during the downward frequency sweep direction, if | f L - f R |>2 f d , then as shown in (d) of Figure 8 , at this time the velocity beat frequency is positive, f d = f L - f R , that is, the target object is approaching the ranging system. Correspondingly, if the frequency sweep direction is downward and the first verification value (the difference between the third frequency and the fourth frequency) is greater than the second verification value (twice the first velocity beat frequency), it can be determined that the target object is approaching the lidar.

[0124] In addition to being able to calculate the movement direction of the target object based on the third beat signal and the fourth beat signal, it is also possible to calculate the distance of the target object based on the third beat signal and the fourth beat signal. Exemplarily, the calculation formula for calculating the distance based on the third frequency and the fourth frequency can be as shown in Formula (5) to Formula (6).

[0125] f R =( f L + f S + f τ ) / 2 (5)

[0126] R = c ·Δ t / 2 = c ·( f R / K f ) / 2 (6)

[0127] Wherein, f R represents the distance beat frequency, f d represents the velocity beat frequency, f L represents the larger value of the 2 beat signals, f S represents the smaller value of the 2 beat signals, f τ represents the delay frequency, c represents the speed of light, Δ t is the time, Kf represents the sweep slope, R represents the distance of the target object.

[0128] Then, based on Formula (5) and Formula (6), it can be known that when calculating the distance of the target object relative to the lidar based on the third beat frequency signal and the fourth beat frequency signal, by obtaining the delay frequency of the second local oscillator signal, the delay frequency is the product of the delay duration of the second local oscillator signal and the magnitude of the sweep slope of the second local oscillator signal, and according to the third frequency, the fourth frequency, and the delay frequency, the second distance of the target object relative to the lidar can be calculated.

[0129] Specifically, first substitute the third frequency, the fourth frequency, and the delay frequency into Formula (5) to obtain the second distance beat frequency corresponding to the third beat frequency signal or the fourth beat frequency signal, and then substitute the second distance beat frequency into Formula (6) to obtain the second distance of the target object relative to the lidar. It can be known from Formula (5) that the second distance beat is half of the sum of the third frequency, the fourth frequency, and the delay frequency.

[0130] In addition, after calculating the velocity direction of the target object relative to the lidar, based on Figure 8 different situations, the velocity beat frequencies in different situations can be calculated respectively, and then the magnitude of the velocity of the target object relative to the lidar can be calculated. Considering that Figure 8 the determination methods of the velocity beat frequencies in different situations in are different, which may be related to the larger value (the third frequency) of the frequencies of the third beat frequency signal and the fourth beat frequency signal, or may be related to the smaller value (the fourth frequency) of the frequencies of the third beat frequency signal and the fourth beat frequency signal. Corresponding step 403 may further include step 403C.

[0131] Step 403C, determine the magnitude of the second velocity of the target object relative to the lidar according to one of the third frequency and the fourth frequency and the second distance beat frequency. Specifically, step 403C may further include step 403C1 and step 403C2.

[0132] Step 403C1, determine the second velocity beat frequency corresponding to the third beat frequency signal or the fourth beat frequency signal according to one of the third frequency and the fourth frequency and the second distance beat frequency.

[0133] Step 403C2, determine the magnitude of the second velocity of the target object relative to the lidar according to the second velocity beat frequency.

[0134] Exemplarily, the calculation formula of the velocity can be as shown in Formula (7).

[0135] ν = λ · f d / 2 (7)

[0136] wherein, f d is the speed beat frequency, and v is the speed. Then, based on formula (7), first, according to one of the third frequency and the fourth frequency and the second distance beat frequency, the second speed beat frequency corresponding to the third beat signal or the fourth beat signal is determined. Furthermore, substituting the second speed beat frequency into formula (7), the magnitude of the second speed of the target object relative to the lidar can be obtained.

[0137] However, the determination methods of the second speed beat frequency ( f d ) are different in different cases. For example, as can be seen from (a) in Figure 8 , during the up-chirp period, and when | f L - f S | > 2 f d , at this time the speed beat frequency is negative, f d = f L - f R . And as can be seen from (b) in Figure 8 , during the up-chirp period, and when | f L - f S | < 2 f d , at this time the speed beat frequency is positive, f d = f R -f S . Correspondingly, when determining the second speed beat frequency, similar to when determining the moving direction, it also includes four cases:

[0138] In case (a), if the sweep direction is up-sweep, and the first check value (the difference between the third frequency and the fourth frequency) is greater than the second check value (twice the first speed beat frequency), it can be determined that the target object is moving away from the lidar. At this time, the second speed beat frequency can be determined by the difference between the larger frequency value (the third frequency) and the second distance beat frequency, that is, f d = f L - f R [corresponding to (a) in Figure 8 . In addition, the second speed beat frequency can also be determined by the smaller frequency value (the fourth frequency), the delay frequency, and the second distance beat frequency; specifically,f d = f R - f L - f τ [Corresponding to Figure 8 in (a) of

[0139] In case (b), if the frequency sweep direction is upward frequency sweep, and the first verification value (the difference between the third frequency and the fourth frequency) is less than the second verification value (twice the first speed beat frequency), it can be determined that the target object is approaching the lidar. At this time, the second speed beat frequency can be determined by the difference between the second distance beat frequency and the smaller value of the frequencies (the fourth frequency), that is, f d = f R - f S [Corresponding to Figure 8 in (b) of f d = f L - f R + f τ [Corresponding to Figure 8 in (b) of

[0140] In case (c), if the frequency sweep direction is downward frequency sweep, and the first verification value (the difference between the third frequency and the fourth frequency) is less than the second verification value (twice the first speed beat frequency), it can be determined that the target object is moving away from the lidar. At this time, the second speed beat frequency can be determined by the difference between the second distance beat frequency and the smaller value of the frequencies (the fourth frequency), that is, f d = f R - f S [Corresponding to Figure 8 in (c) of f d = f L - f R + f τ [Corresponding to Figure 8 in (c) of

[0141] In case (d), if the frequency sweep direction is downward and the first verification value (the difference between the third frequency and the fourth frequency) is greater than the second verification value (twice the first speed beat frequency), it can be determined that the target object is approaching the lidar. At this time, the second speed beat frequency can be determined by the difference between the larger value of the frequencies (the third frequency) and the second distance beat frequency, that is f d = f L - f R [corresponding to Figure 8 in (d)]. In addition, the second speed beat frequency can also be determined by the smaller value of the frequencies (the fourth frequency), the delay frequency, and the second distance beat frequency; specifically, f d = f R - f S - f τ [corresponding to Figure 8 in (d)].

[0142] It should be understood that in the process of calculating the speed and distance based on the third beat signal and the fourth beat signal, the magnitude of the second speed can also directly adopt the value calculated based on the first beat signal and the second beat signal, and the second distance can also directly adopt the value calculated based on the first beat signal and the second beat signal. That is, the magnitude of the first speed calculated based on the first beat signal and the second beat signal can be determined as the magnitude of the second speed corresponding to the third beat signal or the fourth beat signal; the first distance calculated based on the first beat signal and the second beat signal can be determined as the second distance corresponding to the third beat signal or the fourth beat signal.

[0143] It is worth mentioning that the first multiplexed detection signal and the second multiplexed detection signal need to be incident on the same target object, and the above method of determining the velocity direction by comparing the first check value and the second check value is meaningful and reasonable. Therefore, the two channels used for joint demodulation to determine the velocity direction, that is, the above-mentioned first multiplexed detection signal and the second multiplexed detection signal, should be two adjacent beams among the multiple beams emitted by the lidar, so as to ensure that the two beams of light can fall on the same target object. For example, in some embodiments, the lidar can emit four multiplexed detection signals, that is, the lidar has four channels; the above-mentioned first multiplexed detection signal and the second multiplexed detection signal need to be two adjacent beams among the four multiplexed detection signals, such as the two middle beams or the two edge beams. When the lidar emits more than two multiplexed detection signals, two multiplexed detection signals can correspond to the above-mentioned first detection signal and the second detection signal respectively, that is, it includes multiple first multiplexed detection signals and multiple second multiplexed detection signals, and the corresponding first multiplexed detection signal and the second multiplexed detection signal are adjacent; or only two of the multiple multiplexed detection signals can correspond to the above-mentioned first multiplexed detection signal and the second multiplexed detection signal.

[0144] In this embodiment, by introducing an additional delay amount to the local oscillator light of one of the channels in the dual-laser ranging system, when calculating the beat signal of the channel with the introduced delay amount, the moving direction of the target object relative to the lidar can be calculated through a preset verification method. This enables each channel to achieve real-time speed measurement and ranging with only one balanced photodetector. Compared with the method 2 in the related art, it can save half of the hardware resources and greatly reduce the cost of realizing real-time speed measurement and ranging.

[0145] Figure 9 It is a schematic structural diagram of a lidar provided by an embodiment of the present application. Exemplarily, as Figure 9 shown, the lidar 900 includes:

[0146] A light source module 901, configured to generate a first multiplexed detection signal and a second multiplexed detection signal, so that the first multiplexed detection signal and the second multiplexed detection signal respectively detect a target object. Among them, both the first multiplexed detection signal and the second multiplexed detection signal include a first detection signal and a second detection signal with different wavelengths. The first detection signal includes multiple segments of first swept-frequency signals sequentially connected in the time domain, and each segment of the first swept-frequency signal corresponds to a swept-frequency time zone. The swept-frequency waveforms of two adjacent segments of the first swept-frequency signals in the time domain are not collinear. The second detection signal includes multiple segments of second swept-frequency signals sequentially connected in the time domain, and each segment of the second swept-frequency signal corresponds to a swept-frequency time zone. The swept-frequency waveforms of two adjacent segments of the second swept-frequency signals in the time domain are not collinear. Each first swept-frequency signal corresponds to a second swept-frequency signal, and the swept-frequency directions of the first swept-frequency signal and the second swept-frequency signal corresponding to the same swept-frequency time zone are opposite;

[0147] The light source module 901 is further configured to generate at least two first local oscillator signals and at least two second local oscillator signals, where the first local oscillator signal corresponds to the first detection signal, and the second local oscillator signal corresponds to the second detection signal;

[0148] The first photoelectric detection module 902 is configured to receive the first local oscillator signal, the second local oscillator signal, and the first combined wave echo signal, where the first combined wave echo signal is a signal formed by the reflection of the first combined wave detection signal by the target object;

[0149] The delay module 903 is configured to perform a delay process on at least one second local oscillator signal to obtain a second delayed local oscillator signal; and

[0150] The second photoelectric detection module 904 is configured to receive the first local oscillator signal, the second delayed local oscillator signal, and the second combined wave echo signal, where the second combined wave echo signal is a signal formed by the reflection of the second combined wave detection signal by the target object.

[0151] Optionally, the apparatus further includes:

[0152] The first acquisition module is configured to acquire a first frequency and a second frequency corresponding to the first frequency sweep time zone, where the first frequency sweep time zone is one of the frequency sweep time zones, the first local oscillator signal, the second local oscillator signal, and the first combined wave echo signal are beat to obtain a first beat signal and a second beat signal, and the first frequency and the second frequency are respectively the higher one and the lower one of the frequencies of the first beat signal and the second beat signal;

[0153] The second acquisition module is configured to acquire a third frequency and a fourth frequency corresponding to the first frequency sweep time zone, where the first local oscillator signal, the second delayed local oscillator signal, and the second combined wave echo signal are beat to obtain a third beat signal and a fourth beat signal, and the third frequency and the fourth frequency are respectively the higher one and the lower one of the frequencies of the third beat signal and the fourth beat signal;

[0154] The determination module is configured to determine the distance and speed of the target object relative to the lidar according to the first frequency, the second frequency, the third frequency, and the fourth frequency.

[0155] Optionally, the determination module is further configured to:

[0156] Determine the magnitude of the first distance and the first speed of the target object relative to the lidar according to the first frequency and the second frequency;

[0157] Determine the speed direction of the target object relative to the lidar according to the first frequency, the second frequency, the third frequency, and the fourth frequency.

[0158] Optionally, the determination module is further configured to:

[0159] Determine the first distance beat frequency and the first velocity beat frequency corresponding to the first beat signal or the second beat signal according to the first frequency and the second frequency;

[0160] Determine the first distance according to the first distance beat frequency;

[0161] Determine the magnitude of the first velocity according to the first velocity beat frequency.

[0162] Optionally, the determination module is configured to:

[0163] Determine the first velocity beat frequency corresponding to the first beat signal or the second beat signal according to the first frequency and the second frequency;

[0164] Determine the velocity direction of the target object relative to the lidar according to the first velocity beat frequency, the third frequency, and the fourth frequency.

[0165] Optionally, the determination module is further configured to:

[0166] Determine the velocity direction of the target object relative to the lidar according to the magnitude relationship between the first verification value and the second verification value, where the first verification value is the difference between the third frequency and the fourth frequency, and the second verification value is twice the first velocity beat frequency.

[0167] Optionally, if the sweep direction of the first detection signal corresponding to the first sweep time zone is upward sweep, the determination module is further configured to:

[0168] a) If the first verification value is greater than the second verification value, determine that the target object is away from the lidar;

[0169] b) If the first verification value is less than the second verification value, determine that the target object is approaching the lidar;

[0170] If the sweep direction of the first detection signal corresponding to the first sweep time zone is downward sweep, the determination module is further configured to:

[0171] c) If the first verification value is less than the second verification value, determine that the target object is away from the lidar;

[0172] d) If the first verification value is greater than the second verification value, determine that the target object is approaching the lidar.

[0173] Optionally, the determination module is further configured to:

[0174] Determine the second distance of the target object relative to the lidar according to the third frequency, the fourth frequency, and the delay frequency, where the delay frequency is the product of the delay duration of the second local oscillator signal and the magnitude of the sweep slope of the second local oscillator signal.

[0175] Optionally, the determination module is further configured to:

[0176] Determine the second range beat frequency corresponding to the third beat frequency signal or the fourth beat frequency signal according to the third frequency, the fourth frequency, and the delay frequency;

[0177] Determine the second range of the target object relative to the lidar according to the second range beat frequency.

[0178] Optionally, the determining module is further configured to:

[0179] Determine the magnitude of the second velocity of the target object relative to the lidar according to one of the third frequency and the fourth frequency and the second range beat frequency.

[0180] Optionally, the determining module is further configured to:

[0181] Determine the magnitude of the first velocity as the magnitude of the second velocity corresponding to the third beat frequency signal or the fourth beat frequency signal.

[0182] Optionally, the first detection signal is a triangular wave frequency sweep signal or a sawtooth wave frequency sweep signal; the second detection signal is a triangular wave frequency sweep signal or a sawtooth wave frequency sweep signal.

[0183] The above-mentioned first acquisition module, second acquisition module, and determination module may be a processor. The processor may include one or more processing cores, such as a 4-core processor, an 8-core processor, etc. The processor may be implemented in at least one hardware form of DSP (Digital Signal Processing), FPGA (Field-Programmable Gate Array), and PLA (Programmable Logic Array). The processor may also include a main processor and a coprocessor. The main processor is a processor used to process data in the wake state, also known as the CPU (Central Processing Unit); the coprocessor is a low-power processor used to process data in the standby state.

[0184] Figure 10 It is a schematic structural diagram of a lidar provided by an embodiment of the present application.

[0185] Exemplarily, as Figure 10 shown, the lidar 1000 includes: a controller 1001, a light source module 1002, a first photoelectric detection module 1003, a delay module 1004, and a second photoelectric detection module 1005. The controller 1001 is respectively connected to the light source module 1002, the first photoelectric detection module 1003, the delay module 1004, and the second photoelectric detection module 1005; when the controller 1004 runs, it is used to execute the detection method of the lidar in the above-mentioned embodiment.

[0186] The embodiments of the present application further provide a computer-readable storage medium, in which computer program code is stored. When the computer program code runs on a lidar, it causes a computer device to execute the above-related method steps to implement the detection method of the lidar in the above embodiments.

[0187] This embodiment further provides a computer program product. When the computer program product runs on a lidar, it causes a computer device to execute the above-related steps to implement the detection method of the lidar in the above embodiments.

[0188] Through the description of the above embodiments, those skilled in the art can understand that for the convenience and conciseness of description, only the above division of each functional module is used as an example. In actual applications, the above functions can be allocated to different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules to complete all or part of the functions described above.

[0189] In the embodiments provided in the present application, it should be understood that the disclosed device and method can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of modules or units is only a logical functional division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling or direct coupling or communication connection between each other can be through some interfaces. The indirect coupling or communication connection of the device or unit can be in an electrical, mechanical or other form.

[0190] The above content is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present application, and all should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A laser radar detection method, characterized in that: The method comprises: Control the light source module to generate a first combined wave detection signal and a second combined wave detection signal, so that the first combined wave detection signal and the second combined wave detection signal respectively detect the target object, wherein the first combined wave detection signal and the second combined wave detection signal both include a first detection signal and a second detection signal with different wavelengths, the first detection signal includes a plurality of first sweep frequency signals sequentially connected in the time domain, each of the first sweep frequency signals corresponds to a sweep frequency time zone, and the sweep frequency waveforms of two adjacent first sweep frequency signals in the time domain are not collinear, the second detection signal includes a plurality of second sweep frequency signals sequentially connected in the time domain, each of the second sweep frequency signals corresponds to a sweep frequency time zone, and the sweep frequency waveforms of two adjacent second sweep frequency signals in the time domain are not collinear, each of the first sweep frequency signals corresponds to a second sweep frequency signal, and the sweep directions of the first sweep frequency signal and the second sweep frequency signal corresponding to the same sweep frequency time zone are opposite; Controlling the light source module to generate at least two first local oscillation signals and at least two second local oscillation signals, wherein the first local oscillation signal corresponds to the first detection signal, and the second local oscillation signal corresponds to the second detection signal; Controlling the first photoelectric detection module to receive a first local oscillator signal, a second local oscillator signal and a first combined wave echo signal, wherein the first combined wave echo signal is a signal formed by the first combined wave detection signal being reflected by a target object; and Control the second photoelectric detection module to receive the first local oscillator signal, the second delayed local oscillator signal and the second combined wave echo signal, wherein the second delayed local oscillator signal is a signal for delaying the second local oscillator signal, and the second combined wave echo signal is a signal formed by the second combined wave detection signal being reflected by the target object; The laser radar can emit multiple beams of combined detection signals, and the first combined detection signal and the second combined detection signal are two adjacent beams in each of the combined detection signals.

2. The method according to claim 1, characterized in that: The method further comprises: Acquire a first frequency and a second frequency corresponding to a first frequency sweep time zone, wherein the first frequency sweep time zone is one of the frequency sweep time zones, the first local oscillator signal, the second local oscillator signal and the first combined echo signal beat to obtain a first beat frequency signal and a second beat frequency signal, and the first frequency and the second frequency are respectively the higher one and the lower one of the beat frequency of the first beat frequency signal and the beat frequency of the second beat frequency signal; Acquire a third frequency and a fourth frequency corresponding to the first frequency sweep time zone, wherein the first local oscillator signal, the second delayed local oscillator signal and the second combined echo signal beat each other to obtain a third beat frequency signal and a fourth beat frequency signal, and the third frequency and the fourth frequency are respectively the higher one and the lower one of the beat frequency of the third beat frequency signal and the beat frequency of the fourth beat frequency signal; The distance and speed of the target object relative to the laser radar are determined according to the first frequency, the second frequency, the third frequency and the fourth frequency.

3. The method according to claim 2, characterized in that The determining the distance and speed of the target object relative to the laser radar according to the first frequency, the second frequency, the third frequency and the fourth frequency includes: Determine a first distance and a first speed of the target object relative to the laser radar according to the first frequency and the second frequency; The speed direction of the target object relative to the laser radar is determined according to the first frequency, the second frequency, the third frequency and the fourth frequency.

4. The method according to claim 3, characterized in that: The determining, according to the first frequency and the second frequency, a first distance and a first speed of the target object relative to the laser radar includes: Determine a first distance beat frequency and a first speed beat frequency corresponding to the first beat signal or the second beat signal according to the first frequency and the second frequency; determining the first distance according to the first distance beat frequency; The magnitude of the first speed is determined according to the first speed beat frequency.

5. The method according to claim 3, characterized in that: The determining the speed direction of the target object relative to the laser radar according to the first frequency, the second frequency, the third frequency and the fourth frequency includes: Determine a first speed beat frequency corresponding to the first beat signal or the second beat signal according to the first frequency and the second frequency; The speed direction of the target object relative to the laser radar is determined according to the first speed beat frequency, the third frequency and the fourth frequency.

6. The method according to claim 5, characterized in that The determining the speed direction of the target object relative to the laser radar according to the first speed beat frequency, the third frequency and the fourth frequency includes: The speed direction of the target object relative to the laser radar is determined based on the size relationship between the first verification value and the second verification value, wherein the first verification value is the difference between the third frequency and the fourth frequency, and the second verification value is twice the first speed beat frequency.

7. The method according to claim 6, characterized in that: If the sweep direction of the first detection signal corresponding to the first sweep time zone is an upward sweep, determining the speed direction of the target object relative to the laser radar according to the magnitude relationship between the first check value and the second check value includes at least one of the following steps: a) if the first verification value is greater than the second verification value, it is determined that the target object is far away from the laser radar; b) if the first verification value is less than the second verification value, determining that the target object is close to the laser radar; If the sweep direction of the first detection signal corresponding to the first sweep time zone is downward sweep, determining the speed direction of the target object relative to the laser radar according to the magnitude relationship between the first check value and the second check value includes at least one of the following steps: c) if the first verification value is less than the second verification value, determining that the target object is far away from the laser radar; d) If the first verification value is greater than the second verification value, it is determined that the target object is close to the laser radar.

8. The method according to claim 3, characterized in that The determining the distance and speed of the target object relative to the laser radar according to the first frequency, the second frequency, the third frequency and the fourth frequency further includes: The second distance of the target object relative to the laser radar is determined according to the third frequency, the fourth frequency and the delay frequency, wherein the delay frequency is the product of the delay length of the second local oscillator signal and the sweep slope of the second local oscillator signal.

9. The method according to claim 8, characterized in that The determining, according to the third frequency, the fourth frequency and the delay frequency, a second distance of the target object relative to the laser radar comprises: Determine a second distance beat frequency corresponding to the third beat frequency signal or the fourth beat frequency signal according to the third frequency, the fourth frequency and the delay frequency; According to the second distance beat frequency, a second distance of the target object relative to the laser radar is determined.

10. The method according to claim 9, characterized in that The determining the distance and speed of the target object relative to the laser radar according to the first frequency, the second frequency, the third frequency and the fourth frequency further includes: The magnitude of a second speed of the target object relative to the laser radar is determined based on one of the third frequency and the fourth frequency and the second range beat frequency.

11. The method according to claim 3, characterized in that The determining the distance and speed of the target object relative to the laser radar according to the first frequency, the second frequency, the third frequency and the fourth frequency includes: The magnitude of the first speed is determined to be the magnitude of the second speed corresponding to the third beat frequency signal or the fourth beat frequency signal.

12. The method according to claim 1, characterized in that The first detection signal is a triangular wave sweep signal or a sawtooth wave sweep signal; The second detection signal is a triangular wave frequency sweep signal or a sawtooth wave frequency sweep signal.

13. A laser radar, characterized in that: include: A light source module, used for generating a first combined wave detection signal and a second combined wave detection signal, so that the first combined wave detection signal and the second combined wave detection signal respectively detect a target object, wherein the first combined wave detection signal and the second combined wave detection signal both include a first detection signal and a second detection signal with different wavelengths, the first detection signal includes a plurality of first sweep frequency signals sequentially connected in the time domain, each of the first sweep frequency signals corresponds to a sweep frequency time zone, and the sweep frequency waveforms of two adjacent first sweep frequency signals in the time domain are not collinear, the second detection signal includes a plurality of second sweep frequency signals sequentially connected in the time domain, each of the second sweep frequency signals corresponds to a sweep frequency time zone, and the sweep frequency waveforms of two adjacent second sweep frequency signals in the time domain are not collinear, each of the first sweep frequency signals corresponds to a second sweep frequency signal, and the sweep directions of the first sweep frequency signal and the second sweep frequency signal corresponding to the same sweep frequency time zone are opposite, the light source module is also used for generating at least two first local oscillator signals and at least two second local oscillator signals, wherein the first local oscillator signal corresponds to the first detection signal, and the second local oscillator signal corresponds to the second detection signal; A first photoelectric detection module is used to receive a first local oscillator signal, a second local oscillator signal and a first combined wave echo signal, wherein the first combined wave echo signal is a signal formed by the first combined wave detection signal being reflected by a target object; A delay module, used for performing delay processing on at least one beam of the second local oscillator signal to obtain a second delayed local oscillator signal; and A second photoelectric detection module is used to receive the first local oscillator signal, the second delayed local oscillator signal and the second combined wave echo signal, wherein the second combined wave echo signal is a signal formed by the second combined wave detection signal being reflected by the target object; The laser radar can emit multiple beams of combined detection signals, and the first combined detection signal and the second combined detection signal are two adjacent beams in each of the combined detection signals.

14. The laser radar according to claim 13, characterized in that: It also includes a controller, which is connected to the light source module, the first photoelectric detection module and the second photoelectric detection module respectively; The controller is used to execute the laser radar detection method as described in any one of claims 1 to 12.

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