Laser detection method and laser radar

Abstract

The invention discloses a laser detection method and a laser radar. The laser radar comprises a transmitting module, a transmission module, a receiving module and a processing module. After receiving the echo pulse, the transmission module forms a ranging pulse according to at least part of the echo pulse; dividing at least part of the echo pulse into a frequency discrimination pulse and a pulse to be measured, and forming a speed measurement comparison pulse according to the frequency discrimination pulse; the processing module obtains the distance of the obstacle according to the collected distance measurement pulse; the processing module further obtains echo frequency according to the collected speed measurement comparison pulse and the pulse to be measured, so that speed frequency shift is obtained, and then the radial speed of the obstacle is obtained. The laser radar can detect the distance of an obstacle and the radial speed of the obstacle, the requirement for a light source can be effectively lowered, the control complexity of the transmitting module is lowered, and the detection reliability is improved.

Description

Technical Field

[0001] The invention relates to laser detection, and in particular to a laser detection method and a laser radar. Background Art

[0002] LiDAR is a commonly used distance measurement sensor with the characteristics of long detection distance, high resolution, and low environmental interference. It is widely used in intelligent robots, drones, unmanned driving and other fields. In recent years, autonomous driving technology has developed rapidly, and LiDAR, as its core sensor for distance perception, has become indispensable.

[0003] Among the existing laser radars that can measure the speed of obstacles, one is the frequency modulated continuous wave coherent laser radar, which uses the coherent beat frequency of the echo light and the local oscillator light to analyze the distance and speed information of the target based on the spectrum of the beat frequency signal. However, due to the time delay of the echo light relative to the local oscillator light, the triangular wave frequency modulation method commonly used in the frequency modulated continuous wave coherent laser radar cannot handle the measurement of close-range high-speed moving obstacles.

[0004] Moreover, the frequency modulated continuous wave coherent lidar uses linear frequency modulated continuous light, which makes it difficult to control the light source. The linearity of the linear frequency modulated light generated by the light source is prone to deviations, which will directly affect the detection effect and even make it impossible to measure. Summary of the invention

[0005] The problem solved by the present invention is to realize the detection of the distance and speed of obstacles by using relatively simple light sources and detection lights.

[0006] In order to solve the above problems, the present invention provides a laser radar, comprising:

[0007] A transmitting module, wherein the transmitting module is suitable for generating a detection pulse, wherein the detection pulse has an operating frequency and forms an echo pulse after being reflected by an obstacle; a transmitting module, wherein the transmitting module is suitable for receiving the echo pulse and forming a ranging pulse based on at least part of the echo pulse; the transmitting module is also suitable for dividing at least part of the echo pulse into a frequency discrimination pulse and a pulse to be measured, and forming a speed comparison pulse based on the frequency discrimination pulse; a receiving module, wherein the receiving module is suitable for collecting the ranging pulse; the receiving module is also suitable for collecting the speed comparison pulse and the pulse to be measured; a processing module, wherein the processing module is suitable for obtaining the distance of the obstacle based on the collected ranging pulse; the processing module is also suitable for obtaining the echo frequency based on the collected speed comparison pulse and the pulse to be measured, and obtaining the speed frequency shift based on the operating frequency and the echo frequency; the processing module is also suitable for obtaining the radial speed of the obstacle based on the speed frequency shift, wherein the echo frequency is the frequency of the echo pulse.

[0008] Optionally, the detection pulse includes a distance measurement pulse and a speed measurement pulse, the distance measurement pulse forms a speed measurement echo pulse after being reflected by an obstacle, and the speed measurement pulse forms a speed measurement echo pulse after being reflected by an obstacle.

[0009] Optionally, the peak power of the ranging pulse is greater than the peak power of the speed measuring pulse.

[0010] Optionally, the pulse width of the distance measurement pulse is smaller than the pulse width of the speed measurement pulse.

[0011] Optionally, the transmission module outputs a speed measurement comparison pulse of corresponding light intensity based on the demodulation pulse and the echo frequency; the receiving module is suitable for collecting the speed measurement comparison pulse to obtain the light intensity of the speed measurement comparison pulse, and the receiving module is also suitable for collecting the pulse to be measured to obtain the light intensity of the pulse to be measured; the processing module obtains the speed measurement echo signal power of the speed measurement echo pulse based on the light intensity of the speed measurement comparison pulse and the light intensity of the pulse to be measured; the processing module obtains the echo frequency based on the speed measurement echo signal power of the speed measurement echo pulse combined with the frequency intensity curve.

[0012] Optionally, the transmission module includes: a first spectrometer unit, which is suitable for dividing the at least part of the echo pulse into a discrimination pulse and a pulse to be measured; a discrimination unit, which is located in the optical path of the discrimination pulse downstream of the first spectrometer unit, and transmits the discrimination pulse to form the speed measurement comparison pulse.

[0013] Optionally, the splitting ratio of the first splitting unit is 1:N; the ratio of the intensity of the demodulation pulse separated by the first splitting unit to the intensity of the pulse to be measured separated by the first splitting unit is N:1, where N is greater than 1.

[0014] Optionally, the receiving module includes: a first detection unit, the first detection unit is located in the optical path of the speed measurement comparison pulse, and the first detection unit is suitable for collecting the speed measurement comparison pulse; a second detection unit, the second detection unit is located in the optical path of the pulse to be measured, and the second detection unit is suitable for collecting the pulse to be measured; a third detection unit, the third detection unit is located in the optical path of the ranging pulse, and the third detection unit is suitable for collecting the ranging pulse.

[0015] Optionally, at least one of the first detection unit, the second detection unit and the third detection unit is a photoelectric detection unit; the photoelectric detection unit includes: a photosensitive element, which is suitable for collecting light signals and generating electrical signals corresponding to light intensity; a sampling element, which is connected to the photosensitive element and is suitable for sampling the electrical signals generated by the photosensitive element.

[0016] Optionally, at least one of the first detection unit and the second detection unit further includes a variable capacitance energy storage element; the variable capacitance energy storage element further includes: a storage capacitor group, the storage capacitor group is suitable for storing the electrical signal generated by the photosensitive element; a controller, when the receiving module collects the speed comparison pulse and the pulse to be measured, the controller is suitable for changing the capacitance of the storage capacitor group according to the ranging pulse collected by the receiving module.

[0017] Optionally, the storage capacitor group includes: a plurality of integral capacitors and a control switch connected in series with the integral capacitors; according to the ranging pulses collected by the receiving module, the controller controls the opening and closing of the control switch to change the capacitance of the storage capacitor group.

[0018] Optionally, the third detection unit further includes: an amplifying element, wherein the amplifying element is connected in series between the photosensitive element and the sampling element.

[0019] Optionally, the transmission module also includes: a second spectroscopic unit, the second spectroscopic unit is suitable for forming a ranging pulse based on at least part of the echo pulse and transmitting the ranging pulse to the third detection unit, and the second spectroscopic unit is also suitable for transmitting part of the echo pulse to the first spectroscopic unit of the transmission module.

[0020] Optionally, the intensity of the ranging pulse accounts for more than 50% of the intensity of the echo pulse received by the second light splitting unit.

[0021] Optionally, the processing module includes: a distance processing unit, which is suitable for obtaining the distance of the obstacle based on the collected distance measurement pulse; a speed processing unit, which is suitable for obtaining the echo frequency based on the collected speed measurement comparison pulse and the pulse to be measured, and obtaining the speed frequency shift based on the working frequency and the echo frequency; the speed processing unit is also suitable for obtaining the radial speed of the obstacle based on the speed frequency shift, wherein the echo frequency is the frequency of the speed measurement echo pulse.

[0022] Optionally, the transmitting module includes: a light generating unit, the light generating unit is suitable for generating initial light, the initial light is suitable for forming the detection pulse, and the initial light has a preset light intensity; the transmission module is also suitable for separating feedback light from the initial light; the transmission module is also suitable for transmitting the feedback light to form locking contrast light; the receiving module is also suitable for collecting the locking contrast light; the processing module is also suitable for obtaining an initial frequency based on the collected locking contrast light, the initial frequency being the frequency of the initial light; the laser radar also includes: a feedback module, the feedback module is suitable for controlling the transmitting module according to the initial frequency so that the operating frequency is locked at a preset value.

[0023] Optionally, the transmission module further includes: a third light splitting unit, the third light splitting unit is located in the optical path of the initial light downstream of the light generating unit, and the third light splitting unit is suitable for separating feedback light from the initial light.

[0024] Optionally, the transmission module further includes: a selection unit, the selection unit is located in the optical path upstream of the discrimination unit of the transmission module, and the selection unit is suitable for selecting one of the discrimination pulse and the feedback light for transmission.

[0025] Optionally, the selection unit includes an optical switch; when the optical switch conducts the optical path between the first optical splitting unit and the discrimination unit, it disconnects the optical path between the third optical splitting unit and the discrimination unit; when the optical switch conducts the optical path between the third optical splitting unit and the discrimination unit, it disconnects the optical path between the first optical splitting unit and the discrimination unit.

[0026] Optionally, the initial light generated by the light generating unit is direct current light; the light emitting module also includes: a pulse generating unit, the pulse generating unit is located in the optical path downstream of the light generating unit, the pulse generating unit is suitable for converting the initial light into pulse light, and the pulse light is suitable for forming the detection pulse.

[0027] Optionally, the pulse generating unit is located in the optical path between the light generating unit and the third spectroscopic unit; the third spectroscopic unit is suitable for dividing the pulse light into a feedback pulse and the detection pulse; the laser radar also includes: a delay module, which is located in the optical path of the detection pulse downstream of the third spectroscopic unit, and the delay module is suitable for delaying the emission of the detection pulse.

[0028] Optionally, the delay module delays the emission of the detection pulse so that a time when the discrimination unit of the transmission module receives the feedback pulse is different from a time when the discrimination unit of the transmission module receives the discrimination pulse.

[0029] Optionally, the preset value locked by the operating frequency is the Q point of the discriminator of the frequency discrimination unit in the transmission module.

[0030] Accordingly, the present invention also provides a laser detection method, comprising:

[0031] Generate a detection pulse, the detection pulse having an operating frequency; the obstacle reflects the detection pulse to form an echo pulse; receive the echo pulse; form a ranging pulse based on at least part of the echo pulse, and divide at least part of the echo pulse into a frequency discrimination pulse and a pulse to be measured; form a speed comparison pulse based on the frequency discrimination pulse; collect the ranging pulse, the speed comparison pulse and the pulse to be measured; obtain the distance of the obstacle based on the collected ranging pulse; obtain the echo frequency based on the collected speed comparison pulse and the pulse to be measured, wherein the echo frequency is the frequency of the echo pulse; obtain a velocity frequency shift based on the operating frequency and the echo frequency; obtain the radial velocity of the obstacle based on the velocity frequency shift.

[0032] Optionally, in the step of generating a detection pulse, the detection pulse includes a ranging pulse and a speed measuring pulse, the ranging pulse forms a speed measuring echo pulse after being reflected by an obstacle, and the speed measuring pulse forms a speed measuring echo pulse after being reflected by an obstacle.

[0033] Optionally, the peak power of the ranging pulse is greater than the peak power of the speed measuring pulse.

[0034] Optionally, the pulse width of the distance measurement pulse is smaller than the pulse width of the speed measurement pulse.

[0035] Optionally, the step of generating a detection pulse includes: generating the ranging pulse at a first moment; generating the speed measurement pulse at a second moment, the second moment being later than the first moment; the steps of the laser detection method also include: changing the capacitance of a storage capacitor group according to the collected ranging echo pulse, the storage capacitor group being suitable for storing the electrical signal generated by a photosensitive element, and the photosensitive element being suitable for collecting light pulses and generating electrical signals corresponding to the light intensity of the light pulses.

[0036] Optionally, in the step of forming a speed comparison pulse according to the demodulation pulse, the demodulation pulse is received based on the echo frequency, and a speed comparison pulse of corresponding light intensity is output; the step of collecting the ranging pulse, the speed comparison pulse and the pulse to be measured includes: collecting the speed comparison pulse to obtain the light intensity of the speed comparison pulse; collecting the pulse to be measured to obtain the light intensity of the pulse to be measured; the step of obtaining the echo frequency according to the received speed comparison pulse and the pulse to be measured includes: obtaining the speed echo signal power of the speed echo pulse according to the light intensity of the speed comparison pulse and the light intensity of the pulse to be measured; obtaining the echo frequency according to the speed echo signal power of the speed echo pulse in combination with the frequency intensity curve.

[0037] Optionally, the step of generating a detection pulse includes: generating initial light, the initial light is suitable for forming the detection pulse, and the initial light has a preset light intensity; the laser detection method also includes: separating feedback light from the initial light; forming locking contrast light based on the feedback light; collecting the locking contrast light; obtaining an initial frequency based on the collected locking contrast light, the initial frequency being the frequency of the initial light; and controlling the transmitting module to lock the operating frequency at a preset value based on the initial frequency.

[0038] Optionally, it also includes: selecting one of the frequency discrimination pulse and the feedback light for transmission.

[0039] Optionally, the step of selecting one of the discrimination pulse and the feedback light for transmission includes: while opening the optical path of the discrimination pulse, disconnecting the optical path of the feedback light; while opening the optical path of the feedback light, disconnecting the optical path of the discrimination pulse.

[0040] Optionally, in the step of generating initial light, the initial light is direct current light; and the step of generating a detection pulse further includes: converting the initial light into pulse light, wherein the pulse light is suitable for forming the detection pulse.

[0041] Optionally, the method further includes: dividing the pulse light into a feedback pulse and the detection pulse; and delaying the emission of the detection pulse.

[0042] Optionally, in the step of delaying the emission of the detection pulse, the emission of the detection pulse is delayed so that the timing of executing the step of forming a locking contrast light according to the feedback light is different from the timing of executing the step of forming a speed measurement contrast pulse according to the frequency discrimination pulse.

[0043] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0044] In the technical solution disclosed in the present invention, a part of the echo pulse is separated to form a ranging pulse; a part of the echo pulse is divided into a frequency discrimination pulse and a pulse to be measured, and a speed comparison pulse is formed according to the frequency discrimination pulse; the distance of the obstacle is obtained according to the collected ranging pulse; the echo frequency is obtained according to the collected speed comparison pulse and the pulse to be measured, thereby obtaining the speed frequency shift, and then obtaining the radial speed of the obstacle. The laser radar disclosed in the present invention can detect both the distance of the obstacle and the radial speed of the obstacle through the transmission and reception of light once, and can effectively reduce the requirements for the light source, reduce the control complexity of the transmitting module, and improve the detection reliability.

[0045] In the optional solution disclosed in the present invention, feedback light is further separated from the initial light; the feedback light is transmitted to form locking contrast light; an initial frequency is obtained according to the collected locking contrast light, and the initial frequency is the frequency of the initial light; the transmitting module is controlled according to the initial frequency so that the operating frequency is locked at a preset value. The technical solution disclosed in the present invention can lock the operating frequency at a preset value, can effectively ensure the stability of the frequency of the generated detection light, and can effectively ensure the accuracy of the detection result.

[0046] In the optional scheme disclosed in the present invention, at least one of the first detection unit and the second detection unit in the receiving module further includes: a variable capacitance energy storage element; a controller in the variable capacitance energy storage element changes the capacitance of the storage capacitor group according to the collected ranging pulse to improve the dynamic range of detection. Specifically, when the ranging pulse intensity is large, the capacitance of the storage capacitor group in the energy storage element is increased to avoid excessive voltage; when the ranging pulse intensity is small, the capacitance of the storage capacitor group in the energy storage element is reduced to ensure that the integral value can be measured; according to the ranging pulse intensity, the capacitance of the storage capacitor is adjusted to improve the detection sensitivity and accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without creative work. The drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation to the present invention. In the drawings:

[0048] Figure 1 is a functional block diagram of the first embodiment of the laser radar disclosed herein;

[0049] Figure 2 yes Figure 1The frequency intensity curve of the discriminator of the frequency discrimination unit in the transmission module in the laser radar embodiment shown;

[0050] Figure 3 yes Figure 1 A schematic diagram of the structure of a photoelectric detection unit including an energy storage element with a variable capacity in a receiving module in the laser radar embodiment shown;

[0051] Figure 4 yes Figure 1 A schematic diagram of the structure of a photoelectric detection unit including a variable capacitance amplifying element in a receiving module of the laser radar embodiment shown;

[0052] Figure 5 is a functional block diagram of the second embodiment of the laser radar disclosed herein;

[0053] Figure 6 is a functional block diagram of the third embodiment of the laser radar disclosed herein;

[0054] Figure 7 It is a flow chart of an embodiment of the laser detection method disclosed in the present invention. DETAILED DESCRIPTION

[0055] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0056] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0057] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0058] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0059] The disclosure below provides many different embodiments or examples to realize different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplicity and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides various specific examples of processes and materials, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0060] As can be seen from the background technology, the laser radar in the prior art has the problem of being unable to measure the target speed.

[0061] In order to solve the technical problem, the present invention provides a laser radar, comprising:

[0062] A transmitting module, wherein the transmitting module is suitable for generating a detection pulse, wherein the detection pulse has an operating frequency and forms an echo pulse after being reflected by an obstacle; a transmitting module, wherein the transmitting module is suitable for receiving the echo pulse and forming a ranging pulse based on at least part of the echo pulse; the transmitting module is also suitable for dividing at least part of the echo pulse into a frequency discrimination pulse and a pulse to be measured, and forming a speed comparison pulse based on the frequency discrimination pulse; a receiving module, wherein the receiving module is suitable for collecting the ranging pulse; the receiving module is also suitable for collecting the speed comparison pulse and the pulse to be measured; a processing module, wherein the processing module is suitable for obtaining the distance of the obstacle based on the collected ranging pulse; the processing module is also suitable for obtaining the echo frequency based on the collected speed comparison pulse and the pulse to be measured, and obtaining the speed frequency shift based on the operating frequency and the echo frequency; the processing module is also suitable for obtaining the radial speed of the obstacle based on the speed frequency shift, wherein the echo frequency is the frequency of the echo pulse.

[0063] The technical solution of the present invention is to separate part of the echo pulse to form a ranging pulse; to divide part of the echo pulse into a frequency discrimination pulse and a pulse to be measured, and to form a speed comparison pulse according to the frequency discrimination pulse; to obtain the distance of the obstacle according to the collected ranging pulse; to obtain the echo frequency according to the collected speed comparison pulse and the pulse to be measured, thereby obtaining the speed frequency shift, and then obtaining the radial speed of the obstacle. The laser radar disclosed in the present invention can detect both the distance of the obstacle and the radial speed of the obstacle through the transmission and reception of light once, and can effectively reduce the requirements for the light source, reduce the control complexity of the transmitting module, and improve the detection reliability.

[0064] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0065] refer to Figure 1 , showing a functional block diagram of an embodiment of the laser radar disclosed herein.

[0066] The laser radar comprises:

[0067] A transmitting module 110, wherein the transmitting module 110 is suitable for generating a detection pulse, wherein the detection pulse has an operating frequency, and wherein the detection pulse forms an echo pulse after being reflected by an obstacle; a transmitting module 120, wherein the transmitting module 120 is suitable for receiving the echo pulse, and forming a ranging pulse according to at least part of the echo pulse; the transmitting module 120 is also suitable for dividing at least part of the echo pulse into a frequency discrimination pulse and a pulse to be measured, and forming a speed comparison pulse according to the frequency discrimination pulse; a receiving module 130, wherein the receiving module 130 is suitable for collecting the ranging pulse ; The receiving module 130 is also suitable for collecting the speed comparison pulse and the pulse to be measured; the processing module 140, the processing module 140 is suitable for obtaining the distance of the obstacle according to the collected distance measurement pulse; the processing module 140 is also suitable for obtaining the echo frequency according to the collected speed comparison pulse and the pulse to be measured, and obtaining the speed frequency shift according to the working frequency and the echo frequency; the processing module 140 is also suitable for obtaining the radial speed of the obstacle according to the speed frequency shift, wherein the echo frequency is the frequency of the echo pulse.

[0068] The transmission module 120 separates part of the echo pulse to form a ranging pulse; the transmission module 120 also divides part of the echo pulse into a demodulation pulse and a pulse to be measured, and forms a speed comparison pulse according to the demodulation pulse; the processing module 140 obtains the distance of the obstacle according to the collected ranging pulse; the processing module 140 obtains the echo frequency according to the collected speed comparison pulse and the pulse to be measured, thereby obtaining the speed frequency shift, and then obtaining the radial speed of the obstacle. The laser radar disclosed in the present invention can detect both the distance of the obstacle and the radial speed of the obstacle through the transmission and reception of light once, and can effectively reduce the requirements for the light source, reduce the control complexity of the transmitting module, and improve the detection reliability.

[0069] The technical solution of the laser radar embodiment is described in detail below with reference to the accompanying drawings.

[0070] The transmitting module 110 as a light source is suitable for generating light to form a detection pulse.

[0071] In some embodiments of the present disclosure, the transmitting module 110 includes: a light generating unit 111, wherein the light generating unit 111 is suitable for generating initial light, wherein the initial light is suitable for forming the detection pulse, and wherein the initial light has a preset light intensity.

[0072] Specifically, the detection pulse has the same frequency as the initial light generated by the light generating unit 111 , and the frequencies of the initial light and the detection pulse are both the operating frequency f0; the light intensity of the initial light is I0.

[0073] The light generating unit 111 is a light source for generating light. Specifically, the light generating unit 111 may include a laser, wherein the light generating unit 111 may include a distributed feedback laser (DFB), a vertical cavity surface emitting laser (VCSEL), or an edge emitting laser (EEL), or other light-emitting components capable of generating laser light.

[0074] In some specific embodiments, the initial light generated by the light generating unit 111 is direct current light, and the initial light is continuous light; the light emitting module 110 also includes: a pulse generating unit 112, and the pulse generating unit 112 is located in the optical path downstream of the light generating unit 111, and the pulse generating unit 112 is suitable for converting the initial light into pulse light, and the pulse light is suitable for forming the detection pulse.

[0075] Specifically, the pulse generating unit 112 includes a semiconductor optical amplifier (Semi-conductor Optical Amplifier, SOA). The pulse generating unit 112 is formed by using a semiconductor optical amplifier, which can convert continuous initial light into pulsed initial light and amplify the optical signal at the same time.

[0076] In some embodiments of the present invention, the detection pulse includes a distance measurement pulse and a speed measurement pulse. The distance measurement pulse forms a speed measurement echo pulse after being reflected by an obstacle, and the speed measurement pulse forms a speed measurement echo pulse after being reflected by an obstacle.

[0077] The detection pulse is a double pulse, wherein the ranging pulse is used to measure the distance of the obstacle, and the speed pulse is used to measure the radial speed of the obstacle. In some embodiments, the peak power of the ranging pulse is greater than the peak power of the speed pulse; in some embodiments, the pulse width of the ranging pulse is less than the pulse width of the speed pulse.

[0078] Specifically, in the pulse generating unit 112, a dual pulse is used to drive the semiconductor optical amplifier. When the driving pulse is at a high level, the pulse generating unit 112 amplifies the optical signal. When the driving pulse is at a low level, the pulse generating unit 112 reduces the optical loss to zero, thereby converting the input continuous initial light into a pulsed initial light, and the initial light has a greater light intensity.

[0079] Through the control of the driving pulse, the semiconductor optical amplifier in the pulse generating unit 112 forms different detection pulses, wherein one pulse signal amplifies the initial light into a ranging pulse with higher power and narrower pulse width, the ranging pulse is a nanosecond pulse, and the pulse width is generally a few nanoseconds; one pulse signal amplifies the initial light into a speed measuring pulse with lower power and wider pulse width, the speed measuring pulse is a microsecond pulse or a sub-microsecond pulse, and the pulse width is generally a few microseconds or tens of microseconds.

[0080] In some embodiments of the present invention, the transmitting module 110 generates the distance measurement pulse and the speed measurement pulse in a time-sharing manner. Specifically, the transmitting module 110 generates the distance measurement pulse at a first moment and generates the speed measurement pulse at a second moment, and the second moment is later than the first moment.

[0081] The transmission module 120 transmits the detection pulse to realize the emission of the detection pulse; the transmission module 120 also receives and transmits the echo light formed by the detection pulse being reflected by an obstacle.

[0082] Specifically, the transmission module 120 receives and transmits the detection pulse generated by the transmission module 110 to realize the emission of the detection pulse to the external space.

[0083] like Figure 1 In some specific embodiments shown, the laser radar has an optical path arranged in a coaxial structure, and in the laser radar, the optical path of the emitted detection pulse and the optical path of the received echo light partially overlap; the transmission module 120 also includes: a three-terminal transmission unit 126, and the three-terminal transmission unit 126 is suitable for transmitting the detection pulse to achieve the emission of the detection pulse, and the three-terminal transmission device is also suitable for receiving the echo light to separate the echo light from the optical path of the detection pulse.

[0084] The three-terminal transmission unit 126 is used to separate the optical path of the detection pulse and the optical path of the echo light. Specifically, the three-terminal transmission unit 126 includes a circulator. Figure 1 As shown, the three-terminal transmission unit 126 has a first end, a second end and a third end; the first end of the three-terminal transmission unit 126 is connected to the transmitting module 110, and the three-terminal transmission unit 126 transmits the detection pulse input from the first end to the second end for emission; the three-terminal transmission unit 126 is also suitable for transmitting the echo light input from the second end to the third end.

[0085] In other embodiments, the three-terminal transmission unit 126 includes a polarizing beam splitter (PBS) or a semi-transparent and semi-reflective mirror, etc., which can separate the optical paths of the detection light and the echo light.

[0086] It should be noted that, in some embodiments, the transmission module 120 further includes: an amplification unit 128, the amplification unit 128 is located in the optical path of the detection pulse, and the amplification unit 128 is suitable for increasing the light intensity of the detection pulse. The amplification unit 128 includes: an optical fiber amplifier (Erbium-doped Optical Fiber Amplifier, EDFA).

[0087] Specifically, the amplification unit 128 is located in the optical path upstream of the three-port transmission unit 126. Figure 1 In some of the illustrated embodiments, the amplification unit 128 is located in the optical path between the transmission module 110 and the three-port transmission unit 126 .

[0088] In addition, in some embodiments, the transmission module 120 also includes: a lens unit 127, which is located in the optical path downstream of the three-port transmission unit 126, and the lens unit 127 receives the detection pulse transmitted by the three-port transmission unit 126 to emit it, and the lens unit 127 also receives echo light and transmits it to the three-port transmission unit 126.

[0089] Specifically, the lens unit 127 includes at least one lens. Among them, the lens unit 126 includes a collimating lens. Figure 1 As shown, the lens unit 127 corresponds to the second end of the three-terminal transmission unit 126. The lens unit 127 receives the detection pulse output from the second end of the three-terminal transmission unit 126, and shapes or collimates it to emit it to the external space; the lens unit 127 receives the echo light formed by reflection in the external space, and focuses it to input it to the second end of the three-terminal transmission unit 126.

[0090] The initial light generated by the light generating unit 111 is amplified by the pulse generating unit 112 to form a detection pulse, and then amplified by the amplifying unit 128 , and then transmitted through the three-terminal transmission unit 126 and the lens unit 127 before being emitted.

[0091] The transmission module 120 also receives and transmits the echo pulse, and divides the echo pulse into a frequency discrimination pulse and a pulse to be measured, and forms a speed measurement comparison pulse according to the frequency discrimination pulse.

[0092] In some specific embodiments, the laser radar includes a coaxial optical path, and the transmission module 120 includes: a second splitting unit 123, wherein the second splitting unit is suitable for transmitting the echo pulse and separating the ranging pulse from the echo pulse.

[0093] The second light splitting unit 123 is used to split a part from the echo pulse to form a ranging pulse. Specifically, the second light splitting unit 123 includes: a beam splitter. The second light splitting unit 123 has an input end and two output ends; the input end of the second light splitting unit 123 is suitable for inputting the echo light, such as Figure 1 As shown, the input end of the second splitter unit 123 is connected to the third end of the three-end transmission unit 126 to receive the echo pulse transmitted to the third end; one output end of the second splitter unit 123 outputs the ranging pulse, and the other output end outputs the remaining echo pulse.

[0094] In some specific embodiments, the second light splitting unit 123 includes a coupler.

[0095] In some specific embodiments, the intensity of the ranging pulse accounts for more than 50% of the intensity of the echo pulse received by the second light splitting unit 123, and the intensity of the remaining echo pulse output from another output end of the second light splitting unit 123 is less than the intensity of the ranging pulse. Most of the echo pulses are separated to form the ranging pulse, effectively ensuring the distance measurement capability of the laser radar.

[0096] In some embodiments of the present invention, the transmission module 120 further outputs a speed comparison pulse corresponding to the light intensity based on the frequency discrimination pulse and according to the echo frequency.

[0097] In some specific embodiments, the transmission module 120 includes: a first spectrometer unit 121, the first spectrometer unit 121 is suitable for dividing the at least part of the echo pulse into a discrimination pulse and a pulse to be measured; a discrimination unit 122, the discrimination unit 122 is located in the optical path of the discrimination pulse downstream of the first spectrometer unit 121, and the discrimination unit 122 transmits the discrimination pulse to form the speed measurement comparison pulse.

[0098] The first light splitting unit 121 is used to split light according to its light splitting ratio. Specifically, the first light splitting unit 121 is a beam splitter. The first light splitting unit 121 has an input end and two output ends; the input end of the first light splitting unit 121 is suitable for inputting at least part of the echo pulse.

[0099] In some specific embodiments, the first light splitting unit 121 includes a coupler.

[0100] like Figure 1As shown, the second optical splitter unit 123 transmits part of the echo pulse to the first optical splitter unit 121 of the transmission module 120, the input end of the first optical splitter unit 121 is connected to the output end of the second optical splitter unit 123 outputting the remaining echo pulse, and receives the remaining echo pulse separated by the second optical splitter unit 123; the two output ends of the first optical splitter unit 121 output the demodulation pulse and the pulse to be measured respectively.

[0101] In some embodiments of the present disclosure, the splitting ratio of the first splitting unit 121 is 1:N; the ratio of the light intensity of the demodulation pulse separated by the first splitting unit 121 to the light intensity of the pulse to be measured separated by the first splitting unit 121 is N:1, and N is greater than 1; the light intensity of the demodulation pulse separated by the first splitting unit 121 is greater than the light intensity of the pulse to be measured separated by the first splitting unit 121.

[0102] If the obstacle has radial velocity, the movement of the obstacle will cause the echo pulse to produce a Doppler frequency shift relative to the emitted detection pulse, and the echo pulse formed by the obstacle reflection is different from the operating frequency f0 of the emitted detection pulse, and the frequency of the demodulation pulse and the pulse to be measured is different from the operating frequency f0 of the emitted detection pulse. Specifically, the radial velocity of the obstacle can be the relative velocity of the obstacle to the laser radar in the direction of the line connecting the obstacle and the laser radar.

[0103] The demodulation unit 122 is used to form the speed measurement comparison pulse, and the light intensity of the speed measurement comparison pulse formed by the demodulation unit 122 is related to the frequency of the demodulation pulse. The demodulation unit 122 changes the light intensity of the transmitted light signal based on the frequency of the transmitted light signal, thereby outputting a light signal whose light intensity is related to the frequency of the transmitted light signal. The light intensity of the speed measurement comparison pulse is related to the frequency of the demodulation pulse, so when the obstacle has a radial velocity, the light intensity of the speed measurement comparison pulse is not equal to the light intensity of the demodulation pulse, the light intensity of the speed measurement comparison pulse is greater than the light intensity of the demodulation pulse, or the light intensity of the speed measurement comparison pulse is less than the light intensity of the demodulation pulse.

[0104] Specifically, the frequency discriminator 122 includes: a frequency discriminator, which includes at least one of a fiber Bragg grating frequency discriminator and a Mach-Zehnder interferometer frequency discriminator. The frequency discriminator is an optical frequency discriminator, which refers to an optical component whose light intensity of an output light signal corresponds to the frequency of an input light signal, wherein a relationship curve between the light intensity of an output light signal of the optical frequency discriminator and the frequency of an input light signal is a frequency intensity curve f(p) of the frequency discriminator.

[0105] Figure 1In some specific embodiments shown, the frequency discriminator is a frequency discriminator based on the fiber Bragg Grating (FBG) principle; Figure 2 Shows Figure 1 The frequency intensity curve f(p) of the discriminator of the discriminator unit 122 in the transmission module 120 in the laser radar embodiment is shown.

[0106] like Figure 2 As shown, the discriminator has a Q point. When the frequency of the input optical signal is at the Q point, the intensity of the output optical signal of the discriminator is equal to the intensity of the input optical signal. In some embodiments of the present disclosure, the Q point of the discriminator of the discriminator unit 122 matches the operating frequency of the light generated by the transmitting module 110, and the operating frequency of the light generated by the transmitting module 110 is close to the Q point of the discriminator of the discriminator unit 122.

[0107] Continue to refer Figure 1 The laser radar also has a receiving module 130, which collects optical signals and performs photoelectric conversion to generate corresponding electrical signals according to the collected optical signals.

[0108] The receiving module 130 is connected to the transmission module 120 to receive the pulse to be measured and the speed comparison pulse separated by the transmission module 120. The light intensity of the speed comparison pulse formed by the discrimination unit 122 is related to the frequency of the discrimination pulse; and the discrimination pulse and the pulse to be measured are obtained by splitting the echo pulse by the second splitting unit 123 and the first splitting unit 121, so the relationship between the light intensity of the discrimination pulse and the light intensity of the pulse to be measured is related to the splitting ratio of the second splitting unit 123 and the first splitting unit 121.

[0109] In some embodiments of the present disclosure, the receiving module 130 is suitable for collecting the ranging pulse to obtain the light intensity I of the ranging pulse. D The receiving module 130 is suitable for collecting the speed measurement comparison pulse to obtain the light intensity I1 of the speed measurement comparison pulse, and the receiving module 130 is also suitable for collecting the pulse to be measured to obtain the light intensity I2 of the pulse to be measured.

[0110] Specifically, the receiving module 130 includes: a first detection unit 131, the first detection unit 131 is located in the optical path of the speed measurement comparison pulse, and the first detection unit 131 is suitable for collecting the speed measurement comparison pulse; a second detection unit 132, the second detection unit 132 is located in the optical path of the pulse to be measured, and the second detection unit 132 is suitable for collecting the pulse to be measured; a third detection unit 133, the third detection unit 133 is located in the optical path of the ranging pulse, and the third detection unit 133 is suitable for collecting the ranging pulse.

[0111] like Figure 1 As shown, the first detection unit 131 is located in the optical path downstream of the frequency discrimination unit 122 of the transmission module 120, and the first detection unit 131 collects the speed comparison pulse to obtain the light intensity I1 of the speed comparison pulse; the second detection unit 132 is located in the optical path of the pulse to be measured downstream of the first light splitting unit 121, and the second detection unit 132 collects the pulse to be measured to obtain the light intensity I2 of the pulse to be measured; the third detection unit 133 is located in the optical path of the distance measurement pulse downstream of the second light splitting unit 123, and the third detection unit 132 collects the distance measurement pulse to obtain the light intensity I D .

[0112] It should be noted that the third detection unit 133 receives the ranging pulse separated by the second splitting unit 123, the second splitting unit 123 separates the ranging pulse from the echo pulse, the ranging pulse is transmitted to the third detection unit 133, and the third detection unit 133 is connected to the output end of the second splitting unit 123 that outputs the ranging pulse.

[0113] In some embodiments of the present disclosure, at least one of the first detection unit 131, the second detection unit 132 and the third detection unit 133 comprises a photoelectric detection unit; Figure 3 and Figure 4 As shown, the photoelectric detection unit includes: a photosensitive element 130pd, which is suitable for collecting light signals and generating electrical signals corresponding to light intensity; a sampling element 130dc, which is connected to the photosensitive element 130pd, and is suitable for sampling the electrical signals generated by the photosensitive element 130pd.

[0114] The photosensitive element 130pd collects the light signal and generates an electrical signal corresponding to the light intensity of the light signal. The photosensitive element 130pd may include a photodiode (PD), a silicon photomultiplier (SiPM), an avalanche photodiode (APD), or a single photon avalanche diode (SPAD) and other components capable of photoelectric conversion.

[0115] The sampling element 130dc samples the electrical signal generated by the photosensitive element 130pd to achieve analog-to-digital conversion. Specifically, the sampling element 130dc includes an analog-to-digital converter (ADC).

[0116] In some embodiments, the sampling element 130dc serving as the photoelectric detection unit of at least one of the first detection unit 131 and the second detection unit 132 includes a low-speed precision analog-to-digital converter to obtain higher resolution and improve speed measurement sensitivity.

[0117] In some embodiments, the photoelectric detection unit of at least one of the first detection unit 131 and the second detection unit 132 also includes a variable capacitance energy storage element; the variable capacitance energy storage element also includes: a storage capacitor group 130cp, the storage capacitor group 130cp is suitable for integrating the electrical signal generated by the photosensitive element 130pd; a controller 130co, before the receiving module 130 collects the speed comparison pulse and the pulse to be measured, the controller 130co is suitable for changing the capacitance of the storage capacitor group 130cp according to the ranging pulse collected by the receiving module 130.

[0118] The photoelectric detection unit measures the intensity of the collected light signal by means of capacitance integration, and achieves a larger dynamic range by setting a variable capacitance energy storage element, thereby realizing the detection of obstacles at different distances and with different reflectivity.

[0119] In some embodiments of the present invention, the transmitting module 110 generates the distance measurement pulse and the speed measurement pulse in a time-sharing manner. Specifically, the transmitting module 110 generates the distance measurement pulse at a first moment and generates the speed measurement pulse at a second moment, and the second moment is later than the first moment.

[0120] The transmitting module 110 first transmits the ranging pulse and then transmits the speed measuring pulse, and the strength of the ranging pulse and the speed measuring pulse have a preset ratio. According to the strength of the ranging pulse collected by the receiving module 130, the echo strength of the speed measuring pulse can be predicted, and the capacitance of the storage capacitor group 130cp can be changed. Specifically, when the ranging pulse intensity is large, the capacitance of the storage capacitor group 130cp in the energy storage element is increased to avoid excessive voltage; when the ranging pulse intensity is small, the capacitance of the storage capacitor group 130cp in the energy storage element is reduced to ensure that the integral value can be measured; according to the ranging pulse intensity, the capacitance of the storage capacitor group 130cp is adjusted to improve the detection sensitivity and accuracy.

[0121] like Figure 3In some of the embodiments shown, the storage capacitor group 130cp includes: multiple integral capacitors and control switches connected in series with the integral capacitors; according to the ranging pulses collected by the receiving module 130, the controller 130co controls the opening and closing of the control switches to change the capacitance of the storage capacitor group 130cp.

[0122] The storage capacitor group 130cp includes: a plurality of integral capacitors. Specifically, the integral capacitors in the storage capacitor group 130cp have different capacitances, and according to the intensity of the ranging pulse, the integral capacitor with a suitable capacitance is switched by controlling the switch.

[0123] In some specific embodiments, the number of integrating capacitors included in the storage capacitor group 130cp is greater than 2. The storage capacitor group includes an integrating capacitor with a minimum capacitance, an integrating capacitor with a maximum capacitance, and at least one integrating capacitor with a capacitance between the two. The storage capacitor group is switched according to the intensity of the ranging pulse, which can effectively ensure the detection sensitivity and accuracy of the laser radar.

[0124] like Figure 4 In some of the embodiments shown, the third detection unit 133 further includes: an amplifying element 133am, wherein the amplifying element 133am is connected in series between the photosensitive element 130pd and the sampling element 130dc.

[0125] Specific as Figure 4 As shown, after the photosensitive element 130pd in the third detection unit 133 collects the light signal to generate an electrical signal, it is amplified by the amplifier element 133am and then digital-to-analog conversion is achieved through the sampling element 130dc.

[0126] It should be noted that, in some embodiments, the sampling element 130dc serving as the photoelectric detection unit of the third detection unit 131 may also include a time to digital converter (TDC).

[0127] Continue to refer Figure 1 The laser radar also has a processing module 140, which processes the electrical signal generated by the receiving module 130 to obtain the distance and radial velocity of the obstacle.

[0128] The processing module 140 is connected to the receiving module 130 and receives the electrical signal generated after the receiving module 130 collects the distance measurement pulse, the speed measurement comparison pulse and the pulse to be measured.

[0129] like Figure 1In some of the embodiments shown, the processing module 140 includes: a distance processing unit 140d, wherein the distance processing unit 140d is suitable for obtaining the distance of the obstacle based on the collected distance measurement pulse; a speed processing unit 140v, wherein the speed processing unit 140v is suitable for obtaining the echo frequency based on the collected speed measurement comparison pulse and the pulse to be measured, and obtaining the speed frequency shift based on the working frequency and the echo frequency; the speed processing unit 140v is also suitable for obtaining the radial speed of the obstacle based on the speed frequency shift, wherein the echo frequency is the frequency of the speed measurement echo pulse.

[0130] In some embodiments, the laser radar uses the time-of-flight principle for ranging. Specifically, the distance processing unit 140 obtains the echo time according to the ranging pulse collected by the third detection unit 133, and the echo time is the time when the third detection unit 133 receives the ranging pulse; the distance processing unit 140 obtains the time of flight (TOF) of the light signal corresponding to the obstacle according to the echo time and the emission time, wherein the emission time is the time when the detection pulse is emitted, and the flight time of the light signal is the time difference between the echo time and the emission time; the distance processing unit 140 obtains the distance of the obstacle according to the flight time.

[0131] It should be noted that, in some embodiments of the present invention, the distance processing unit 140 in the processing module 140 adopts the leading edge method to obtain the echo moment, that is, the moment when the leading edge of the echo waveform of the received ranging pulse exceeds a preset threshold intensity is used as the echo moment.

[0132] In some other embodiments, the distance processing unit 140 in the processing module 140 may obtain the echo time by using the centroid method, that is, taking the time corresponding to the centroid of the echo waveform of the ranging pulse as the echo time. The present disclosure does not limit the method for determining the echo time.

[0133] In some embodiments of the present disclosure, the sampling element 130dc as the photoelectric detection unit of the third detection unit 131 includes: a high-speed analog-to-digital converter. Specifically, the high-speed analog-to-digital converter is connected to the third detection unit 133, collects the electrical signal output by the third detection unit 133 and performs analog-to-digital conversion. The sampling element 130dc includes a high-speed analog-to-digital converter, which can improve the sampling accuracy of the electrical signal of the ranging echo pulse, thereby improving the ranging accuracy.

[0134] In some embodiments of the present disclosure, the processing module 140 obtains the speed measurement echo signal power P of the speed measurement echo pulse based on the light intensity I1 of the speed measurement comparison pulse and the light intensity I2 of the pulse to be measured; the processing module 140 obtains the echo frequency f' based on the speed measurement echo signal power P of the speed measurement echo pulse combined with the frequency intensity curve f(p).

[0135] Specifically, the speed processing unit 140v includes: a first processing element, the first processing element is suitable for obtaining the echo signal power P of the speed measurement echo pulse according to the light intensity I1 of the speed measurement comparison pulse and the light intensity I2 of the pulse to be measured, combined with the splitting ratio of the first splitting unit 121 of the transmission module 120; a second processing element, the second processing element is suitable for obtaining the echo frequency f' according to the speed measurement echo signal power P of the speed measurement echo pulse, combined with the frequency intensity curve f(p); a third processing element, the third processing element is suitable for obtaining the speed frequency shift f according to the working frequency f0 and the echo frequency f'. v ; a fourth processing element, wherein the fourth processing element is suitable for obtaining the radial velocity v of the obstacle based on the velocity frequency shift.

[0136] The demodulation pulse that forms the speed measurement comparison pulse and the pulse to be measured are parts of the echo pulse formed by splitting according to the splitting ratio of 1:N of the first splitter unit 121. In some specific embodiments, the processing module 140 is suitable for obtaining the normalized echo signal power P of the echo pulse based on the light intensity I1 of the speed measurement comparison pulse and the light intensity I2 of the pulse to be measured, combined with the splitting ratio of 1:N of the first splitter unit 121 of the transmission module 120; the processing module 140 is also suitable for obtaining the echo frequency f' based on the echo signal power, combined with the frequency intensity curve f(p) of the demodulation unit 122 of the transmission module 120.

[0137] In some embodiments, the first processing element pre-stores the splitting ratio 1:N of the first splitting unit 121, and the first processing element obtains the echo signal power P of the echo pulse according to the light intensity I1 of the speed measurement comparison pulse and the light intensity I2 of the pulse to be measured, combined with the splitting ratio 1:N of the first splitting unit 121 of the transmission module 120. Specifically, the echo signal power of the echo pulse obtained by the first processing element of the processing module 140 is the normalized echo signal power P,

[0138] A frequency intensity curve f(p) is pre-stored in the second processing element, and the pre-stored frequency intensity curve f(p) is a normalized frequency intensity curve f(p). Therefore, the second processing element obtains the echo frequency f' based on the normalized echo signal power P obtained by the first processing element and the pre-stored normalized frequency intensity curve f(p).

[0139] The third processing element obtains the velocity translation f according to the echo frequency f' obtained by the second processing element and the operating frequency f0. v , f v =f'-f0; the fourth processing element translates the echo frequency velocity f obtained by the third processing element v , obtain the radial velocity v of the obstacle,

[0140] refer to Figure 5 , showing a functional block diagram of another embodiment of the laser radar disclosed in the present invention.

[0141] The same as the above embodiment, the present disclosure will not repeat it here. The difference from the above embodiment is that: Figure 5 In some of the embodiments shown, the laser radar can also lock the operating frequency of the detection pulse generated by the transmitting module 110.

[0142] Figure 5 In some of the embodiments shown, the transmitting module 210 includes: a light generating unit 211, wherein the light generating unit 211 is suitable for generating initial light, wherein the initial light is suitable for forming a detection pulse, and wherein the initial light has a preset light intensity I0; the transmission module 220 is also suitable for separating feedback light from the initial light; the transmission module 220 is also suitable for transmitting the feedback light to form locking contrast light; the receiving module 230 is also suitable for collecting the locking contrast light; the processing module 240 is also suitable for obtaining an initial frequency based on the collected locking contrast light, wherein the initial frequency is the frequency of the initial light; the laser radar also includes: a feedback module 250, wherein the feedback module 250 is suitable for controlling the transmitting module 210 based on the initial frequency so that the operating frequency is locked at a preset value.

[0143] The feedback module 250 can lock the initial frequency of the initial light at a preset value to prevent the operating frequency of the detection pulse generated by the transmitting module 210 from drifting, and can effectively ensure the stability of the frequency of the generated detection light and the accuracy of the detection result.

[0144] In order to separate the feedback light from the initial light, in some embodiments, the transmission module 220 further includes: a third splitting unit 225, wherein the third splitting unit 225 is located in the optical path of the initial light downstream of the light generating unit 211, and the third splitting unit 225 is suitable for separating the feedback light from the initial light.

[0145] The third light splitting unit 225 includes a beam splitter. The third light splitting unit 225 includes an input end and two output ends. The input end of the third light splitting unit 225 is suitable for inputting the initial light. The two input ends of the third light splitting unit 225 output the detection pulse and the feedback light respectively.

[0146] In some specific embodiments, the third light splitting unit 225 includes a coupler.

[0147] Specifically, the intensity of the feedback light can be determined according to the preset light intensity I0 of the initial light and the splitting ratio of the third light splitting unit 225 .

[0148] It should be noted that the light generating unit 211 generates continuous initial light, and the initial light is direct current light; the light transmitting module 210 further includes a pulse generating unit 212 for converting the continuous initial light into a pulsed initial light; Figure 5 In some of the embodiments shown, the third light splitting unit 225 is located in the optical path between the light generating unit 211 and the pulse generating unit 212, and the third light splitting unit 225 separates continuous feedback light from the continuous initial light, and the feedback light is also direct current light.

[0149] The input end of the third spectroscopic unit 225 is connected to the light generating unit 211 to input the initial light generated by the light generating unit 211; an output end of the third spectroscopic unit 225 is connected to the pulse generating unit 212 to transmit part of the initial light to the pulse generating unit 212 as a detection pulse, which is output after being transmitted through the three-terminal transmission unit 225 and the lens unit 226; the other output end of the third spectroscopic unit 225 transmits the remaining part of the initial light to the demodulation unit 222 of the transmission module 220.

[0150] In order to achieve multiplexing of the discrimination unit 222, in some embodiments, the transmission module 220 also includes: a selection unit 224, which is located in the optical path upstream of the discrimination unit 222 of the transmission module 220, and the selection unit 224 is suitable for selecting one of the discrimination pulse and the feedback light for transmission.

[0151] The selection unit 224 selects the optical signal input to the discrimination unit 222 to switch the laser radar between the speed measurement mode and the frequency lock mode. In some specific embodiments, the selection unit 224 includes an optical switch; when the optical switch conducts the optical path between the first optical splitter unit 221 and the discrimination unit 222, the optical switch disconnects the optical path between the third optical splitter unit 225 and the discrimination unit 222; when the optical switch conducts the optical path between the third optical splitter unit 225 and the discrimination unit 222, the optical switch disconnects the optical path between the first optical splitter unit 221 and the discrimination unit 222.

[0152] like Figure 5 As shown, the optical switch has a first input terminal, a second input terminal and an output terminal. The first input terminal of the optical switch is suitable for inputting the feedback light, the second input terminal of the optical switch is suitable for inputting the discrimination pulse, and the output terminal of the optical switch is connected to the discrimination unit 222.

[0153] The first input end of the optical switch is connected to an output end of the third optical splitting unit 225 to receive the feedback light split by the third optical splitting unit 225, and the second input end of the optical switch is connected to the first optical splitting unit 221 to receive the discrimination pulse split by the first optical splitting unit 221; the optical switch selectively connects one of the optical path between the first input end and the output end and the optical path between the second input end and the output end to realize the selective transmission of the discrimination pulse and the feedback light.

[0154] The optical switch conducts the optical path between the second input end and the output end, and disconnects the optical path between the first input end and the output end. The optical path between the first spectrometer 221 and the discrimination unit 222 is conducted, and the optical path between the third spectrometer 225 and the discrimination unit 222 is disconnected. The selection unit 222 transmits the discrimination pulse to the discrimination unit 222. The laser radar is in the speed measurement mode. The discrimination unit 222 inputs the discrimination pulse separated from the echo pulse; the first detection unit 231 collects the speed measurement comparison pulse formed according to the discrimination pulse; the processing module 240 obtains the echo frequency, that is, the frequency of the echo pulse, and then the radial velocity v of the obstacle can be obtained.

[0155] The optical switch conducts the optical path between the first input end and the output end, and disconnects the optical path between the second input end and the output end. The optical path between the third optical splitter 225 and the frequency discrimination unit 222 is conducted, and the optical path between the first optical splitter 221 and the frequency discrimination unit 222 is disconnected. The selection unit 222 transmits the feedback light to the frequency discrimination unit 222. The laser radar is in a frequency locking mode. The frequency discrimination unit 222 inputs the feedback light separated from the initial light. The first detection unit 231 collects the locking contrast light formed according to the feedback light. The processing module 240 obtains the initial frequency, that is, the frequency of the initial light generated by the light generating unit 211.

[0156] The feedback module 250 is connected to the processing module 240 to obtain the initial frequency; the feedback module 250 is also connected to the light generating unit 211 to control the light generating unit 211 to lock the operating frequency according to the initial frequency.

[0157] Specifically, the processing module 240 obtains the normalized optical power of the locking contrast light according to the intensity of the feedback light, the splitting ratio of the second splitting unit 223, and the intensity of the locking contrast light, and then obtains the initial frequency according to the frequency intensity curve f(p).

[0158] Specifically, the feedback module 250 changes the current of the light generating unit 211 according to the difference between the initial frequency and the operating frequency, so that the frequency of the light generated by the light generating unit 2111 is locked at a preset value.

[0159] In some embodiments of the present disclosure, the preset value to which the working frequency is locked is the Q point of the frequency discriminator of the frequency discrimination unit 222 in the transmission module 220 . Figure 5 In the laser radar shown, the discriminator of the discriminator unit 222 in the transmission module 220 is a Mach-Zehnder Interferometer (MZI); the intensity of the optical signal output by the Mach-Zehnder Interferometer varies periodically with the frequency of the input light.

[0160] Specifically, the discriminator of the discriminator unit 222 in the transmission module 220 has a Q point, and the preset value locked by the working frequency is the frequency corresponding to the Q point of the discriminator. When the frequency of the light input to the discriminator unit 222 is the preset value, the light intensity of the light output by the discriminator unit 222 is equal to the light intensity of the light input to the discriminator unit 222. When the laser radar is in the frequency locking mode, when the frequency of the initial light generated by the light generating unit 211 is the preset value, the light intensity of the feedback light is equal to the light intensity of the locking contrast light; when the frequency of the initial light generated by the light generating unit 211 deviates from the preset value, the light intensity of the locking contrast light will deviate from the light intensity of the feedback light, and the feedback module 250 adjusts the current of the light generating unit 211 based on the deviation of the light intensity of the locking contrast light relative to the feedback light to change the frequency of the initial light generated by the light generating unit 211 so as to return it to the preset value.

[0161] In the above-mentioned embodiment, the output light intensity of the Mach-Zehnder interferometer discriminator changes periodically with the frequency of the input light, that is, the Mach-Zehnder interferometer discriminator has multiple Q points, and the multiple Q points correspond to different operating frequencies. During the feedback process, the working point of the Mach-Zehnder interferometer discriminator can be locked at any Q point. Specifically, when the frequency of the initial light shifts, the working point of the Mach-Zehnder interferometer discriminator can be locked at the Q point closest to the initial light frequency after the shift through feedback, so as to reduce the feedback adjustment cycle and improve the feedback efficiency and effectiveness.

[0162] It should be noted that, in some embodiments, the pulse generating unit 212 includes a semiconductor optical amplifier, and the pulse generating unit 212 is driven by a pulse signal. When the laser radar is in the speed measurement mode, the driving pulse of the pulse generating unit 212 is at a high level, and the light generated by the light generating unit is amplified to form a pulsed detection pulse; when the laser radar is in the frequency locking mode, the pulse generating unit 212 consumes the light generated by the light generating unit to avoid light emission.

[0163] It should also be noted that, in the aforementioned embodiment, the third optical splitter unit 225 is located in the optical path between the light generating unit 211 and the pulse generating unit 212, and the selection unit 224 is provided to realize the selection of the optical signal input to the frequency discrimination unit 222. In other embodiments of the present disclosure, the third optical splitter unit may also be provided in the optical path downstream of the pulse generating unit, and the feedback light and the detection pulse may be prevented from being coherent in the frequency discrimination unit by delaying the emission of the detection pulse.

[0164] refer to Figure 6 , shows a functional block diagram of another embodiment of the laser radar disclosed in the present invention.

[0165] The same as the above embodiment, the present disclosure will not repeat it here. Figure 6 As shown, the pulse generating unit 312 is located in the optical path between the light generating unit 311 and the third spectroscopic unit 325; the third spectroscopic unit 325 is suitable for dividing the pulsed initial light into a feedback pulse and a detection pulse; the laser radar also includes: a delay module 328, the delay module 328 is located in the optical path of the detection pulse downstream of the third spectroscopic unit 325, and the delay module 328 is suitable for delaying the emission of the detection pulse.

[0166] The continuous initial light generated by the light generating unit 311 is converted into a pulsed initial light by the pulse generating unit 312; the third optical splitting unit 325 divides the pulsed initial light output by the pulse generating unit 312 into a feedback pulse transmitted to the discrimination unit 322 and a detection pulse transmitted to the three-terminal transmission unit 325; wherein part of the feedback pulse is transmitted to the discrimination unit 322 by the first optical splitting unit 321 for feedback control of the light source.

[0167] On the other hand, after the detection pulse is delayed by the delay module 328, it is transmitted through the three-terminal transmission unit 325 and the lens unit 326 to achieve emission; the formed echo pulse is transmitted to the first spectrometer unit 321 by the lens unit 326 and the three-terminal transmission unit 325, and the first spectrometer unit 321 divides the echo pulse into a demodulation pulse transmitted to the demodulation unit 322 and a pulse to be measured transmitted to the second detection unit 332 for speed measurement.

[0168] In some embodiments of the present disclosure, the delay module 328 delays the emission of the detection pulse so that the time when the discrimination unit 322 of the transmission module 320 receives the feedback pulse is different from the time when the discrimination unit 322 of the transmission module 320 receives the discrimination pulse.

[0169] The delay module 328 makes the emission of the detection pulse and the reception of the echo pulse staggered in time. The feedback module 350 locks the light feedback generated by the light generating unit 311 at a preset value, and the detection pulse emitted to the external space is delayed by the delay module 328, so that the time when the discrimination pulse formed by the echo pulse is transmitted to the discrimination unit 322 is staggered with the time when the feedback pulse formed by the initial light is transmitted to the discrimination unit 322, for example, the time when the discrimination pulse is transmitted to the discrimination unit 322 is later than the time when the feedback pulse is transmitted to the discrimination unit 322, so as to avoid interference between the discrimination pulse and the feedback pulse, realize time division multiplexing of the frequency locking mode and the speed measurement mode, and can effectively reduce costs and improve reliability.

[0170] Correspondingly, the present disclosure also provides a laser detection method.

[0171] The laser detection method includes: executing step S110 to generate a detection pulse, wherein the detection pulse has an operating frequency; the obstacle reflects the detection pulse to form an echo pulse; executing step S120 to receive the echo pulse; executing step S130 to form a ranging pulse according to at least part of the echo pulse, and divide at least part of the echo pulse into a frequency discrimination pulse and a pulse to be measured; executing step S140 to form a speed comparison pulse according to the frequency discrimination pulse; executing step S150 to collect the ranging pulse, the speed comparison pulse and the pulse to be measured; executing step S160 to obtain the distance of the obstacle according to the collected ranging pulse; executing step S170 to obtain the echo frequency according to the collected speed comparison pulse and the pulse to be measured, wherein the echo frequency is the frequency of the echo pulse; executing step S180 to obtain a velocity frequency shift according to the operating frequency and the echo frequency; and executing step S190 to obtain the radial velocity of the obstacle according to the velocity frequency shift.

[0172] In some embodiments of the present disclosure, the laser detection method is the laser detection method used by the laser radar of the present disclosure. The specific technical solution of the laser detection method can refer to the above-mentioned embodiments of the laser radar.

[0173] like Figure 7 As shown, step S110 is first performed to generate a detection pulse.

[0174] In some embodiments of the present disclosure, executing step S110, the step of generating a detection pulse includes: generating initial light, wherein the initial light is suitable for forming the detection pulse, and the initial light has a preset light intensity.

[0175] Specifically, the initial light and the detection pulse have the same frequency, and the frequencies of the initial light and the detection pulse are both operating frequency f0; the light intensity of the initial light is I0.

[0176] In some embodiments, the initial light can be generated by a laser, and the laser can be a distributed feedback laser (DFB), such as a vertical cavity surface emitting laser (Vertical-CavitySurface-Emitting Laser, referred to as VCSEL), an edge emitting laser (Edge-emitting Laser, referred to as EEL), or other light-emitting components that can generate lasers.

[0177] In some specific embodiments, in the step of generating initial light, the generated initial light is direct current light, and the initial light is continuous light; executing step S110, the step of generating a detection pulse also includes: converting the initial light into pulse light, and the pulse light is suitable for forming the detection pulse.

[0178] Specifically, the initial light may be converted into pulse light by a semiconductor optical amplifier (Semi-conductor Optical Amplifier, SOA), which can achieve amplification of optical signals while converting the continuous initial light into pulse light.

[0179] In some embodiments of the present invention, step S110 is executed to generate a detection pulse, wherein the detection pulse includes a ranging pulse and a speed measurement pulse, wherein the ranging pulse forms a speed measurement echo pulse after being reflected by an obstacle, and the speed measurement pulse forms a speed measurement echo pulse after being reflected by an obstacle.

[0180] The detection pulse is a double pulse, wherein the ranging pulse is used to measure the distance of the obstacle, and the speed pulse is used to measure the radial speed of the obstacle. In some embodiments, in the step of generating the detection pulse in step S110, the peak power of the ranging pulse is greater than the peak power of the speed pulse; in some embodiments, in the step of generating the detection pulse in step S110, the pulse width of the ranging pulse is less than the pulse width of the speed pulse.

[0181] Specifically, the semiconductor optical amplifier is driven by double pulses. When the driving pulse is at a high level, the optical signal is amplified, and when the driving pulse is at a low level, the optical loss is zero, thereby converting the input continuous initial light into pulsed light with greater light intensity.

[0182] By controlling the driving pulse, the semiconductor optical amplifier forms different detection pulses, wherein one pulse signal amplifies the initial light into a ranging pulse with a higher power and a narrower pulse. The ranging pulse is a nanosecond pulse, and the pulse width is generally a few nanoseconds; and one pulse signal amplifies the initial light into a speed measurement pulse with a lower power and a wider pulse. The speed measurement pulse is a microsecond pulse or a sub-microsecond pulse, and the pulse width is generally a few microseconds or tens of microseconds.

[0183] In some embodiments of the present invention, in the step of generating a detection pulse in step S110, the step of generating the detection pulse includes: generating the ranging pulse and the speed measuring pulse in time sharing. Specifically, in the step of generating a detection pulse in step S110, the step of generating the detection pulse includes: generating the ranging pulse at a first moment, generating the speed measuring pulse at a second moment, and the second moment is later than the first moment.

[0184] The detection pulse is transmitted to the external space, and is reflected by obstacles in the external space to form an echo pulse (such as Figure 7 (shown in the dashed box).

[0185] Then, step S120 is executed to receive the echo pulse; and step S130 is executed to form a ranging pulse according to at least part of the echo pulse, and to divide at least part of the echo pulse into a frequency discrimination pulse and a pulse to be measured.

[0186] Specifically, executing step S130, the step of forming a ranging pulse according to at least part of the echo pulse, and dividing at least part of the echo pulse into a frequency discrimination pulse and a pulse to be measured includes: transmitting the echo pulse; separating the ranging pulse from the echo pulse; and dividing the remaining echo pulse after separating the ranging pulse into a frequency discrimination pulse and a pulse to be measured.

[0187] In some embodiments, in the step of separating the ranging pulse from the echo pulse, the intensity of the ranging pulse accounts for more than 50% of the intensity of the received echo pulse, and the intensity of the remaining echo pulse after the ranging pulse is separated is less than the intensity of the ranging pulse. Most of the echo pulses are separated to form the ranging pulse, effectively ensuring the distance measurement capability of the laser radar.

[0188] In some embodiments, in the step of dividing the echo pulse remaining after the ranging pulse is divided into the frequency discrimination pulse and the pulse to be measured, the echo pulse remaining after the ranging pulse is divided into the frequency discrimination pulse and the pulse to be measured at a preset splitting ratio.

[0189] Specifically, in the step of separating the remaining echo pulses after separating the ranging pulses into frequency discrimination pulses and pulses to be measured, the ratio of the light intensity of the separated frequency discrimination pulses to the light intensity of the separated pulses to be measured is N:1, where N is greater than 1; the light intensity of the separated frequency discrimination pulses is greater than the light intensity of the separated pulses to be measured.

[0190] Afterwards, step S140 is executed to form a speed measurement comparison pulse according to the frequency discrimination pulse.

[0191] Specifically, step S140 is executed, in the step of forming a ranging comparison pulse according to the frequency discrimination pulse, the frequency discrimination pulse is transmitted to form the ranging comparison pulse.

[0192] In some embodiments, step S140 is executed, in the step of forming a speed measurement comparison pulse according to the frequency discrimination pulse, a speed measurement comparison pulse of corresponding light intensity is output based on the frequency discrimination pulse and according to the echo frequency.

[0193] If the obstacle has radial velocity, the movement of the obstacle will cause the echo pulse to produce a Doppler frequency shift relative to the emitted detection pulse, the echo pulse formed by the obstacle reflection is different from the operating frequency f0 of the emitted detection pulse, and the frequency of the demodulation pulse and the pulse to be measured is different from the operating frequency f0 of the emitted detection pulse. Specifically, the radial velocity of the obstacle can be the relative velocity of the obstacle to the laser speed measuring device in the direction of the line connecting the obstacle and the laser speed measuring device.

[0194] Execute step S140, in the step of forming a distance measurement comparison pulse according to the frequency discrimination pulse, the speed measurement comparison pulse is formed, and the light intensity of the formed speed measurement comparison pulse is related to the frequency of the frequency discrimination pulse. Execute step S140, in the step of forming a distance measurement comparison pulse according to the frequency discrimination pulse, based on the frequency of the transmitted light signal, the light intensity of the transmitted light signal is changed, so as to form an optical signal with a light intensity related to the frequency of the transmitted light signal. The light intensity of the speed measurement comparison pulse is related to the frequency of the frequency discrimination pulse, so when the obstacle has a radial velocity, the light intensity of the speed measurement comparison pulse is not equal to the light intensity of the frequency discrimination pulse, the light intensity of the speed measurement comparison pulse is greater than the light intensity of the frequency discrimination pulse, or the light intensity of the speed measurement comparison pulse is less than the light intensity of the frequency discrimination pulse.

[0195] Specifically, a frequency discriminator can be used to form a distance measurement comparison pulse according to the frequency discriminator pulse. The frequency discriminator includes at least one of a fiber Bragg grating frequency discriminator and a Mach-Zehnder interferometer frequency discriminator. The frequency discriminator is an optical frequency discriminator, which refers to an optical component whose light intensity of an output light signal corresponds to the frequency of an input light signal, wherein a relationship curve between the light intensity of an output light signal of the optical frequency discriminator and the frequency of an input light signal is a frequency intensity curve f(p) of the frequency discriminator.

[0196] Figure 1 In some specific embodiments shown, the frequency discriminator is a frequency discriminator based on the fiber Bragg Grating (FBG) principle; Figure 2 Shows Figure 7 The frequency intensity curve f(p) of the discriminator used in the laser detection method shown.

[0197] like Figure 2 As shown, the discriminator has a Q point. When the frequency of the input optical signal is at the Q point, the intensity of the output optical signal of the discriminator is equal to the intensity of the input optical signal. In some embodiments of the present disclosure, the Q point of the discriminator matches the operating frequency of the light, and the operating frequency is close to the Q point of the discriminator.

[0198] Continue to refer Figure 7Then, step S150 is performed to collect the distance measurement pulse, the speed measurement comparison pulse and the pulse to be measured. Specifically, the distance measurement pulse, the speed measurement comparison pulse and the pulse to be measured are subjected to photoelectric conversion, and optical signals are collected and corresponding electrical signals are generated according to the collected optical signals.

[0199] The light intensity of the speed measurement comparison pulse is related to the frequency of the demodulation pulse; and the demodulation pulse and the pulse to be measured are obtained by splitting the echo pulse twice, so the relationship between the light intensity of the demodulation pulse and the light intensity of the pulse to be measured is related to the splitting ratio of the two splittings.

[0200] In some embodiments of the present disclosure, step S150 is performed to collect the ranging pulse, the speed comparison pulse and the pulse to be measured, and the ranging pulse is collected to obtain the light intensity I of the ranging pulse. D ; Collect the speed measurement comparison pulse to obtain the light intensity I1 of the speed measurement comparison pulse, and collect the pulse to be measured to obtain the light intensity I2 of the pulse to be measured.

[0201] In some embodiments, step S150 is executed to collect the distance measurement pulse, the speed measurement comparison pulse and the pulse to be measured, and a photosensitive element is used to collect light signals and generate electrical signals corresponding to the light intensity; and the electrical signals generated by the photosensitive element are sampled by a sampling element.

[0202] Among them, the photosensitive element 130pd can be a photodiode (Photo Diode, PD), a silicon photomultiplier (Silicon photomultiplier, SiPM), an avalanche photodiode (Avalanche Photo Diode, APD), or even a single photon avalanche photodiode (Single Photon Avalanche Diode, SPAD) and other components that can realize photoelectric conversion; the sampling element 130dc includes: an analog to digital converter (Analog to Digital Converter, ADC).

[0203] In some embodiments, the speed measurement comparison pulse and the pulse to be measured can be collected by a low-speed precision digital-to-analog converter to obtain higher resolution and improve speed measurement sensitivity; the distance measurement pulse can be collected by a high-speed digital-to-analog converter.

[0204] In some embodiments of the present invention, in the step of executing step S110 and generating a detection pulse, the step of generating a detection pulse includes: first generating a ranging pulse and then generating a speed measurement pulse; the steps of the laser detection method also include: changing the capacitance of a storage capacitor group according to the collected ranging echo pulse, wherein the storage capacitor group is suitable for storing the electrical signal generated by the photosensitive element. The intensity of the collected light signal is measured by capacitance integration, and the capacitance of the storage capacitor group is variable, which can achieve a larger dynamic range, thereby realizing the detection of obstacles at different distances and different reflectivity.

[0205] The ranging pulse is emitted first, and then the speed measuring pulse is emitted. According to the intensity of the collected ranging pulse, the capacitance of the storage capacitor group is changed: when the ranging pulse intensity is relatively large, the capacitance of the storage capacitor group in the energy storage element is increased to avoid excessive voltage; when the ranging pulse intensity is relatively small, the capacitance of the storage capacitor group in the energy storage element is reduced to ensure that the integral value can be measured; according to the ranging pulse intensity, the capacitance of the storage capacitor group is adjusted to improve the detection sensitivity and accuracy.

[0206] Then, step S160 to step S190 are executed to obtain the distance and radial velocity of the obstacle.

[0207] Wherein, after executing step S150 to collect the distance measurement pulse, the speed measurement comparison pulse and the pulse to be measured, executing step S160 to obtain the distance of the obstacle according to the collected distance measurement pulse.

[0208] In some embodiments, the laser radar uses the time-of-flight principle for ranging. Specifically, in the step of obtaining the distance of the obstacle according to the collected ranging pulses, executing step S160, the echo time is obtained according to the collected ranging pulses, and the echo time is the time when the ranging pulses are collected; the time of flight (TOF) of the light signal corresponding to the obstacle is obtained according to the echo time and the emission time, wherein the emission time is the time when the detection pulses are emitted; and the distance of the obstacle is obtained according to the flight time.

[0209] Wherein, after executing step S150 to collect the distance measurement pulse, the speed measurement comparison pulse and the pulse to be measured, executing step S170 to obtain the echo frequency according to the received speed measurement comparison pulse and the pulse to be measured.

[0210] In some specific embodiments, step S170 is executed, and the step of obtaining the echo frequency f' according to the received speed measurement comparison pulse and the pulse to be measured includes: obtaining the normalized speed measurement echo signal power P of the speed measurement echo pulse according to the light intensity I1 of the speed measurement comparison pulse and the light intensity I2 of the pulse to be measured; and obtaining the echo frequency f' according to the speed measurement echo signal power P of the speed measurement echo pulse in combination with the frequency intensity curve f(p).

[0211] The demodulation pulse that forms the speed comparison pulse and the pulse to be measured are parts of the echo pulse formed by splitting according to a preset splitting ratio of 1:N. In some specific embodiments, step S170 is executed, and in the step of obtaining the echo frequency f' according to the received speed comparison pulse and the pulse to be measured, the echo signal power P of the echo pulse is obtained according to the light intensity I1 of the speed comparison pulse and the light intensity I2 of the pulse to be measured, combined with the preset splitting ratio of 1:N; the echo frequency f' is obtained according to the echo signal power P, combined with the frequency intensity curve f(p).

[0212] In some embodiments, the preset splitting ratio is 1:N, and the echo signal power P of the echo pulse is obtained according to the light intensity I1 of the speed measurement comparison pulse and the light intensity I2 of the pulse to be measured, combined with the splitting ratio 1:N.

[0213] A frequency intensity curve f(p) is pre-stored, and the pre-stored frequency intensity curve f(p) is a normalized frequency intensity curve f(p). Therefore, according to the obtained normalized echo signal power P, combined with the pre-stored normalized frequency intensity curve f(p), the echo frequency f' is obtained; according to the obtained echo frequency f', combined with the working frequency f0, the velocity translation f is obtained. v , f v =f'-f0; according to the obtained echo frequency speed translation f v , obtain the radial velocity v of the obstacle,

[0214] In other embodiments of the present disclosure, the laser detection method can also lock the operating frequency of the detection pulse. The initial frequency of the initial light is locked at a preset value to avoid drift of the operating frequency, which can effectively ensure the stability of the generated detection light frequency and the accuracy of the detection result.

[0215] In some embodiments, the laser detection method further includes: separating feedback light from the initial light; forming locking contrast light according to the feedback light; collecting the locking contrast light; obtaining an initial frequency according to the collected locking contrast light, wherein the initial frequency is the frequency of the initial light; and locking the operating frequency at a preset value according to the initial frequency. The initial frequency of the initial light is locked at a preset value to avoid drift of the operating frequency of the detection pulse, reduce the requirements on the light source, and reduce the difficulty of controlling the light source.

[0216] It should be noted that, in some embodiments, in the step of generating initial light, the generated initial light is DC light, and the initial light is continuous light; the step of generating a detection pulse also includes: converting the initial light into pulse light, and the pulse light is suitable for forming the detection pulse; in the step of separating feedback light from the initial light, continuous feedback light is separated from the continuous initial light, and the feedback light is also DC light.

[0217] In some specific embodiments, the laser detection method further comprises: selecting one of the discrimination pulse and the feedback light for transmission. Specifically, in the step of selecting one of the discrimination pulse and the feedback light for transmission, while opening the optical path of the discrimination pulse, the optical path of the feedback light is disconnected; while opening the optical path of the feedback light, the optical path of the discrimination pulse is disconnected.

[0218] The step of selecting one of the discrimination pulse and the feedback light for transmission can be performed by an optical switch. In some specific embodiments, the optical switch disconnects the optical path of the feedback light while conducting the optical path of the discrimination pulse; and disconnects the optical path of the discrimination pulse while conducting the optical path of the feedback light.

[0219] The optical switch opens the optical path of the frequency discrimination pulse and disconnects the optical path of the feedback light; the frequency discrimination pulse is transmitted; what is collected is the speed measurement comparison pulse formed according to the frequency discrimination pulse; what is obtained is the echo frequency, that is, the frequency of the echo pulse, and then the radial velocity v of the obstacle can be obtained.

[0220] The optical switch conducts the optical path of the feedback light while disconnecting the optical path of the demodulation pulse; the feedback light is transmitted; the collected light is the locking contrast light formed according to the feedback light; the initial frequency is obtained, that is, the frequency of the generated initial light; and then the operating frequency is locked according to the initial frequency. Specifically, according to the difference between the initial frequency and the operating frequency, the laser current is changed so that the frequency of the generated light is locked at a preset value.

[0221] In some embodiments of the present disclosure, the preset value locked by the working frequency is the Q point of the frequency discriminator of the frequency discriminator unit 222 in the transmission module 220. In some embodiments, the frequency discriminator used is a Mach-Zehnder Interferometer (MZI); the intensity of the optical signal output by the Mach-Zehnder Interferometer varies periodically with the frequency of the input light.

[0222] Specifically, the frequency discriminator has a Q point, and the preset value locked by the working frequency is the frequency corresponding to the Q point of the frequency discriminator. When the frequency of the input light is the preset value, the light intensity of the output light is equal to the light intensity of the input light. When the frequency of the generated initial light is the preset value, the light intensity of the feedback light is equal to the light intensity of the locking contrast light; when the frequency of the generated initial light deviates from the preset value, the light intensity of the locking contrast light will deviate from the light intensity of the feedback light, and based on the deviation of the light intensity of the locking contrast light relative to the feedback light, the laser current is adjusted to change the frequency of the generated initial light so that it returns to the preset value.

[0223] In the above-mentioned embodiment, the output light intensity of the Mach-Zehnder interferometer discriminator changes periodically with the frequency of the input light, that is, the Mach-Zehnder interferometer discriminator has multiple Q points, and the multiple Q points correspond to different operating frequencies. During the feedback process, the working point of the Mach-Zehnder interferometer discriminator can be locked at any Q point. Specifically, when the frequency of the initial light shifts, the working point of the Mach-Zehnder interferometer discriminator can be locked at the Q point closest to the initial light frequency after the shift through feedback, so as to reduce the feedback adjustment cycle and improve the feedback efficiency and effectiveness.

[0224] In other embodiments of the present invention, the feedback light and the detection pulse can be delayed to avoid coherence in the demodulation unit; in some embodiments, the laser detection method also includes: dividing the pulse light into a feedback pulse and the detection pulse; and delaying the emission of the detection pulse.

[0225] The continuous initial light generated is converted into pulsed initial light; the pulsed initial light is divided into feedback pulse and detection pulse; among them, part of the feedback pulse is used for feedback control of the light source; on the other hand, the detection pulse is delayed and then emitted; the formed echo pulse is received and divided into a frequency demodulation pulse and a pulse to be measured for speed measurement.

[0226] In some embodiments, in the step of delaying the emission of the detection pulse, the emission of the detection pulse is delayed so that the timing of executing the step of forming a locking contrast light according to the feedback light is different from the timing of executing the step of forming a speed measurement contrast pulse according to the frequency discrimination pulse.

[0227] The emission of the detection pulse and the reception of the echo pulse are staggered in time. The generated light feedback is locked at a preset value, and the detection pulse emitted to the external space is emitted after a delay, so that the moment of executing the step of forming a speed measurement comparison pulse according to the frequency discrimination pulse is staggered with the moment of executing the step of forming a locking comparison light according to the feedback light, for example, the moment of executing the step of forming a locking comparison light according to the feedback light is later than the moment of executing the step of forming a speed measurement comparison pulse according to the frequency discrimination pulse, thereby avoiding interference between the frequency discrimination pulse and the feedback pulse, realizing time division multiplexing of the frequency locking mode and the speed measurement mode, and being able to effectively reduce costs and improve reliability.

[0228] In summary, a portion of the echo pulse is separated to form a ranging pulse; a portion of the echo pulse is divided into a demodulation pulse and a pulse to be measured, and a speed comparison pulse is formed according to the demodulation pulse; the distance of the obstacle is obtained according to the collected ranging pulse; the echo frequency is obtained according to the collected speed comparison pulse and the pulse to be measured, thereby obtaining the speed frequency shift, and then obtaining the radial speed of the obstacle. The laser radar disclosed in the present invention can detect both the distance of the obstacle and the radial speed of the obstacle, and can effectively reduce the requirements for the light source, reduce the control complexity of the transmitting module, and improve the detection reliability.

[0229] Moreover, feedback light is separated from the initial light; the feedback light is transmitted to form locking contrast light; an initial frequency is obtained according to the collected locking contrast light, and the initial frequency is the frequency of the initial light; the transmitting module is controlled according to the initial frequency so that the operating frequency is locked at a preset value. The disclosed technical solution can lock the operating frequency at a preset value, can effectively ensure the stability of the frequency of the generated detection light, and can effectively reduce the requirements for the light source.

[0230] In addition, at least one of the first detection unit and the second detection unit in the receiving module further includes: a variable capacitance energy storage element; a controller in the variable capacitance energy storage element changes the capacitance of the storage capacitor group according to the collected ranging pulse: when the ranging pulse intensity is large, the capacitance of the storage capacitor group in the energy storage element is increased to avoid excessive voltage; when the ranging pulse intensity is small, the capacitance of the storage capacitor group in the energy storage element is reduced to ensure that the integral value can be measured; according to the ranging pulse intensity, the capacitance of the storage capacitor is adjusted to improve the detection sensitivity and accuracy.

[0231] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A laser radar, characterized in that: include: A transmitting module, wherein the transmitting module is suitable for generating a detection pulse, wherein the detection pulse has an operating frequency, and wherein the detection pulse forms an echo pulse after being reflected by an obstacle; A transmission module, wherein the transmission module is adapted to receive the echo pulses and form a distance measurement pulse according to at least part of the echo pulses; the transmission module is also adapted to divide at least part of the echo pulses into a frequency discrimination pulse and a pulse to be measured, and form a speed measurement comparison pulse according to the frequency discrimination pulse; A receiving module, wherein the receiving module is suitable for collecting the ranging pulse; The receiving module is also suitable for collecting the speed comparison pulse and the pulse to be measured; A processing module, wherein the processing module is suitable for obtaining the distance of the obstacle according to the collected ranging pulses; the processing module is also suitable for obtaining the echo frequency according to the collected speed comparison pulses and the pulses to be measured, and obtaining the speed frequency shift according to the working frequency and the echo frequency; the processing module is also suitable for obtaining the radial speed of the obstacle according to the speed frequency shift, wherein the echo frequency is the frequency of the echo pulse.

2. The laser radar according to claim 1, characterized in that The detection pulse includes a distance measurement pulse and a speed measurement pulse. The distance measurement pulse forms a speed measurement echo pulse after being reflected by an obstacle, and the speed measurement pulse forms a speed measurement echo pulse after being reflected by an obstacle.

3. The laser radar according to claim 2, characterized in that The peak power of the distance measuring pulse is greater than the peak power of the speed measuring pulse.

4. The laser radar according to claim 2, characterized in that The pulse width of the distance measuring pulse is smaller than the pulse width of the speed measuring pulse.

5. The laser radar according to any one of claims 1 to 4, characterized in that The transmission module outputs a speed comparison pulse corresponding to the light intensity based on the frequency discrimination pulse and the echo frequency; The receiving module is suitable for collecting the speed measurement comparison pulse to obtain the light intensity of the speed measurement comparison pulse, and the receiving module is also suitable for collecting the pulse to be measured to obtain the light intensity of the pulse to be measured; The processing module obtains the speed measurement echo signal power of the speed measurement echo pulse according to the light intensity of the speed measurement comparison pulse and the light intensity of the pulse to be measured; the processing module obtains the echo frequency according to the speed measurement echo signal power of the speed measurement echo pulse combined with the frequency intensity curve.

6. The laser radar according to claim 5, characterized in that The transmission module comprises: a first light splitting unit, wherein the first light splitting unit is adapted to split the at least part of the echo pulses into frequency discrimination pulses and pulses to be measured; A frequency discrimination unit is located in the optical path of the frequency discrimination pulse downstream of the first light splitting unit, and the frequency discrimination unit transmits the frequency discrimination pulse to form the speed measurement comparison pulse.

7. The laser radar according to claim 6, characterized in that The splitting ratio of the first splitting unit is 1:N; the ratio of the intensity of the demodulation pulse split by the first splitting unit to the intensity of the pulse to be measured split by the first splitting unit is N:1, where N is greater than 1.

8. The laser radar according to claim 1, characterized in that: The receiving module comprises: a first detection unit, the first detection unit being located in the optical path of the speed measurement comparison pulse, and the first detection unit being suitable for collecting the speed measurement comparison pulse; A second detection unit, the second detection unit is located in the optical path of the pulse to be measured, and the second detection unit is suitable for collecting the pulse to be measured; A third detection unit, wherein the third detection unit is located in the optical path of the ranging pulse, and the third detection unit is suitable for collecting the ranging pulse.

9. The laser radar according to claim 8, characterized in that: At least one of the first detection unit, the second detection unit and the third detection unit is a photoelectric detection unit; The photoelectric detection unit comprises: A photosensitive element, wherein the photosensitive element is suitable for collecting light signals and generating electrical signals corresponding to light intensity; A sampling element is connected to the photosensitive element, and the sampling element is suitable for sampling the electrical signal generated by the photosensitive element.

10. The laser radar according to claim 9, characterized in that: At least one of the first detection unit and the second detection unit further includes an energy storage element with a variable capacitance; The variable capacitance energy storage element further includes: A storage capacitor group, wherein the storage capacitor group is suitable for storing the electrical signal generated by the photosensitive element; The controller is adapted to change the capacitance of the storage capacitor group according to the ranging pulse collected by the receiving module when the receiving module collects the speed comparison pulse and the pulse to be measured.

11. The laser radar according to claim 10, characterized in that: The storage capacitor group includes: a plurality of integral capacitors and a control switch connected in series with the integral capacitors; According to the ranging pulses collected by the receiving module, the controller controls the opening and closing of the control switch to change the capacitance of the storage capacitor group.

12. The laser radar according to claim 9, characterized in that: The third detection unit further includes: an amplifying element, which is connected in series between the photosensitive element and the sampling element.

13. The laser radar according to claim 8, characterized in that The transmission module also includes: The second spectroscopic unit is adapted to form a ranging pulse according to at least part of the echo pulse and transmit the ranging pulse to the third detection unit, and the second spectroscopic unit is also adapted to transmit part of the echo pulse to the first spectroscopic unit of the transmission module.

14. The laser radar according to claim 13, characterized in that: The intensity of the ranging pulse accounts for more than 50% of the intensity of the echo pulse received by the second light splitting unit.

15. The laser radar according to claim 1, characterized in that: The processing module comprises: A distance processing unit, wherein the distance processing unit is adapted to obtain the distance of the obstacle according to the collected ranging pulses; A velocity processing unit, wherein the velocity processing unit is suitable for obtaining an echo frequency based on the collected velocity measurement comparison pulse and the pulse to be measured, and obtaining a velocity frequency shift based on the operating frequency and the echo frequency; the velocity processing unit is also suitable for obtaining a radial velocity of the obstacle based on the velocity frequency shift, wherein the echo frequency is the frequency of the velocity measurement echo pulse.

16. The laser radar according to any one of claims 1 to 4, characterized in that: The transmitting module comprises: a light generating unit, the light generating unit is suitable for generating initial light, the initial light is suitable for forming the detection pulse, and the initial light has a preset light intensity; The transmission module is also suitable for separating feedback light from the initial light; the transmission module is also suitable for transmitting the feedback light to form locking contrast light; The receiving module is also suitable for collecting the locking contrast light; The processing module is also adapted to obtain an initial frequency according to the collected locking contrast light, wherein the initial frequency is the frequency of the initial light; The laser radar further includes: a feedback module, which is suitable for controlling the transmitting module according to the initial frequency so that the operating frequency is locked at a preset value.

17. The laser radar according to claim 16, characterized in that: The transmission module also includes: A third light splitting unit is located in the optical path of the initial light downstream of the light generating unit, and is suitable for separating feedback light from the initial light.

18. The laser radar according to claim 17, characterized in that: The transmission module also includes: A selection unit is located in the optical path upstream of the frequency discrimination unit of the transmission module, and is suitable for selecting one of the frequency discrimination pulse and the feedback light for transmission.

19. The laser radar according to claim 18, characterized in that: The selection unit includes an optical switch; The optical switch disconnects the optical path between the third optical splitter unit and the frequency discrimination unit when conducting the optical path between the first optical splitter unit and the frequency discrimination unit; The optical switch disconnects the optical path between the first optical splitting unit and the frequency discrimination unit when conducting the optical path between the third optical splitting unit and the frequency discrimination unit.

20. The laser radar according to claim 16, characterized in that: The initial light generated by the light generating unit is direct current light; The optical transmission module also includes: A pulse generating unit is located in the optical path downstream of the light generating unit, and the pulse generating unit is suitable for converting the initial light into pulse light, and the pulse light is suitable for forming the detection pulse.

21. The laser radar according to claim 20, characterized in that The pulse generating unit is located in the optical path between the light generating unit and the third light splitting unit; The third light splitting unit is suitable for splitting the pulse light into a feedback pulse and the detection pulse; The laser radar further includes: a delay module, which is located in the optical path of the detection pulse downstream of the third splitting unit, and is suitable for delaying the emission of the detection pulse.

22. The laser radar according to claim 21, characterized in that The delay module delays the emission of the detection pulse so that a time when the frequency discrimination unit of the transmission module receives the feedback pulse is different from a time when the frequency discrimination unit of the transmission module receives the discrimination pulse.

23. The laser radar according to claim 16, characterized in that: The preset value to which the working frequency is locked is the Q point of the frequency discriminator of the frequency discrimination unit in the transmission module.

24. A laser detection method, characterized in that: include: generating a detection pulse, wherein the detection pulse has an operating frequency; The obstacle reflects the detection pulse to form an echo pulse; receiving the echo pulse; Forming ranging pulses according to at least part of the echo pulses, and dividing at least part of the echo pulses into frequency discrimination pulses and pulses to be measured; forming a speed measurement comparison pulse according to the frequency discrimination pulse; Collecting the distance measurement pulse, the speed measurement comparison pulse and the pulse to be measured; Obtaining the distance of the obstacle according to the collected ranging pulses; Obtaining an echo frequency according to the collected speed comparison pulse and the pulse to be measured, wherein the echo frequency is the frequency of the echo pulse; Obtaining a velocity frequency shift according to the operating frequency and the echo frequency; The radial velocity of the obstacle is obtained according to the velocity frequency shift.

25. The laser detection method according to claim 24, characterized in that: In the step of generating a detection pulse, the detection pulse includes a distance measurement pulse and a speed measurement pulse. The distance measurement pulse forms a speed measurement echo pulse after being reflected by an obstacle, and the speed measurement pulse forms a speed measurement echo pulse after being reflected by an obstacle.

26. The laser detection method according to claim 25, characterized in that: The peak power of the distance measuring pulse is greater than the peak power of the speed measuring pulse.

27. The laser detection method according to claim 25, characterized in that: The pulse width of the distance measuring pulse is smaller than the pulse width of the speed measuring pulse.

28. The laser detection method according to claim 25, characterized in that: The step of generating a detection pulse comprises: generating the distance measurement pulse at a first moment; generating the speed measurement pulse at a second moment, the second moment being later than the first moment; The steps of the laser detection method also include: changing the capacitance of a storage capacitor group according to the collected ranging echo pulses, wherein the storage capacitor group is suitable for storing electrical signals generated by a photosensitive element, and the photosensitive element is suitable for collecting light pulses and generating electrical signals corresponding to the light intensity of the light pulses.

29. The laser detection method according to any one of claims 24 to 28, characterized in that: In the step of forming a speed comparison pulse according to the frequency discrimination pulse, based on the echo frequency, the frequency discrimination pulse is received and a speed comparison pulse of corresponding light intensity is output; The steps of collecting the distance measuring pulse, the speed measuring comparison pulse and the pulse to be measured include: collecting the speed measuring comparison pulse to obtain the light intensity of the speed measuring comparison pulse; collecting the pulse to be measured to obtain the light intensity of the pulse to be measured; The step of obtaining the echo frequency according to the received speed measurement comparison pulse and the pulse to be measured includes: obtaining the speed measurement echo signal power of the speed measurement echo pulse according to the light intensity of the speed measurement comparison pulse and the light intensity of the pulse to be measured; and obtaining the echo frequency according to the speed measurement echo signal power of the speed measurement echo pulse combined with the frequency intensity curve.

30. The laser detection method according to any one of claims 24 to 28, characterized in that: The step of generating the detection pulse includes: generating initial light, the initial light being suitable for forming the detection pulse, the initial light having a preset light intensity; The laser detection method further comprises: Feedback light is separated from the initial light; locking contrast light is formed according to the feedback light; the locking contrast light is collected; an initial frequency is obtained according to the collected locking contrast light, and the initial frequency is the frequency of the initial light; and a transmitting module is controlled according to the initial frequency to lock the operating frequency at a preset value.

31. The laser detection method according to claim 30, characterized in that: Also includes: One of the frequency discrimination pulse and the feedback light is selected for transmission.

32. The laser detection method according to claim 30, characterized in that: The step of selecting one of the frequency discrimination pulse and the feedback light for transmission comprises: while opening the optical path of the frequency discrimination pulse, disconnecting the optical path of the feedback light; While the optical path of the feedback light is turned on, the optical path of the frequency discrimination pulse is turned off.

33. The laser detection method according to claim 30, characterized in that: In the step of generating initial light, the initial light is direct current light; The step of generating the detection pulse further includes: converting the initial light into pulse light, wherein the pulse light is suitable for forming the detection pulse.

34. The laser detection method according to claim 33, characterized in that: Also includes: The pulse light is divided into a feedback pulse and the detection pulse; and the emission of the detection pulse is delayed.

35. The laser detection method according to claim 34, characterized in that: In the step of delaying the emission of the detection pulse, the emission of the detection pulse is delayed so that the timing of executing the step of forming a locking comparison light according to the feedback light is different from the timing of executing the step of forming a speed measurement comparison pulse according to the frequency discrimination pulse.

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