Laser ranging method and device and storage medium thereof

Abstract

The invention provides a laser ranging method and device and a storage medium, and the method comprises the steps: respectively determining the flight time of a pulse from emission to reflection through the laser frequency and the related phase change, determining a low-precision distance through the flight time, carrying out the interference of the reflected pulse and local continuous laser, obtaining the interference information, and carrying out the measurement of the interference information. The method comprises the following steps: acquiring a low-precision distance, synthesizing pulses with different wavelengths to obtain a corresponding synthesized wavelength, determining a coefficient for calculating the high-precision distance through interference information, the synthesized wavelength and the low-precision distance, and calculating a residual distance for determining the high-precision distance through the interference information. And finally, a high-precision distance is calculated through the coefficient, the residual distance and the synthetic wavelength, so that the accuracy and precision of laser ranging are improved, and the ranging precision of the to-be-measured target is met under the condition that the precision is met on the basis of time-of-flight ranging and in combination with interference of laser pulses.

Description

Technical Field

[0001] The present invention relates to the technical field of laser ranging, and in particular to a laser ranging method, a device and a storage medium thereof. Background Art

[0002] Currently, the time-of-flight (TOF) method is commonly used to measure the distance to a target. While TOF is suitable for fast, long-distance measurements, it can only achieve sub-millimeter accuracy due to limitations in time interval measurement accuracy. Therefore, how to achieve distance measurement for long-distance targets while maintaining sufficient accuracy has become an urgent problem. Summary of the Invention

[0003] The main technical problem solved by the present invention is that the existing distance measurement of the target to be measured cannot meet the requirements of accuracy and long-distance distance measurement at the same time.

[0004] According to a first aspect, a laser ranging method is provided, the method comprising: sending a flight ranging pulse and receiving a flight reflected pulse reflected by a target to be measured, thereby obtaining an initial time interval between sending the transmitted flight ranging pulse and receiving the flight reflected pulse; sending a first ranging pulse of a first wavelength and a first reference pulse of a first wavelength, and receiving a first ranging reflected pulse reflected by the target to be measured and a first reference reflected pulse reflected by the first reference pulse from a reference surface, wherein the flight ranging pulse and the first ranging pulse are the same pulse, or the flight ranging pulse and the first ranging pulse are two different pulses sent simultaneously; sending a second ranging pulse of a second wavelength and a second reference pulse of a second wavelength, and receiving a second ranging reflected pulse reflected by the target to be measured and a second reference reflected pulse reflected by the second reference pulse from a reference surface; interfering the first ranging reflected pulse with a first local continuous wave to obtain first ranging interference information, and obtaining a first ranging interference information based on the first reference reflected pulse. and interfering with a first local continuous wave to obtain first reference interference information, wherein the first local continuous wave and the first ranging pulse belong to the same light source; interfering the second ranging reflected pulse with the second local continuous wave to obtain second ranging interference information, and interfering the second reference reflected pulse with the second local continuous wave to obtain second reference interference information, wherein the second local continuous wave and the second ranging pulse belong to the same light source; determining an error time interval according to the first reference pulse and the first reference reflected pulse; determining an initial ranging distance according to the initial time interval and the error time interval; determining a first synthetic wavelength according to the first wavelength and the second wavelength, and determining a first coefficient according to the initial ranging distance and the first synthetic wavelength, wherein the first coefficient represents a multiple of half of the first synthetic wavelength contained in the distance to be measured corresponding to the target to be measured, and the first coefficient is an integer; determining a first ranging result of the distance to be measured according to the first coefficient, the first synthetic wavelength, the first ranging interference information, the first reference interference information, the second ranging interference information, and the second reference interference information.

[0005] According to a second aspect, a laser ranging device is provided, comprising: a first transmitting device for transmitting a ranging pulse and receiving a ranging pulse reflected by a target to be measured, thereby obtaining an initial time interval between transmitting the ranging pulse and receiving the ranging pulse; a second transmitting device for transmitting a first ranging pulse of a first wavelength and a first reference pulse of a first wavelength, and receiving a first ranging pulse reflected by the target to be measured and a first reference pulse reflected by the first reference pulse from a reference surface, wherein the ranging pulse and the first ranging pulse are the same pulse or two different pulses transmitted simultaneously; a third transmitting device for transmitting a second ranging pulse of a second wavelength and a second reference pulse of a second wavelength, and receiving a second ranging pulse reflected by the target to be measured and a second reference pulse reflected by the second reference pulse from the reference surface; and a first interference information determining module for interfering the first ranging pulse with a first local continuous wave to obtain first ranging interference information, and performing interference analysis based on the first reference reflected pulse and the first local continuous wave. a first coefficient determination module for determining a first synthetic wavelength based on the first wavelength and the second wavelength, and determining a first coefficient based on the initial ranging distance and the first synthetic wavelength, wherein the first coefficient represents a multiple of half of the first synthetic wavelength included in the distance to be measured corresponding to the target to be measured, and the first coefficient is an integer; a first ranging result determination module for determining a first ranging result for the distance to be measured based on the first coefficient, the first synthetic wavelength, the first ranging interference information, the first synthetic wavelength, the first ranging interference information, the first benchmark interference information, the second ranging interference information, and the second benchmark interference information.

[0006] According to a third aspect of an embodiment of the present application, a computer-readable storage medium is provided, on which computer-readable instructions are stored. When the computer-readable instructions are executed by a processor, the laser ranging method as described above is implemented.

[0007] According to a fourth aspect of an embodiment of the present application, an electronic device is provided, comprising: a processor; and a memory, wherein the memory stores computer-readable instructions, and when the computer-readable instructions are executed by the processor, the laser ranging method described above is implemented.

[0008] According to the laser ranging method / device of the above embodiment, an initial time interval as a flight time interval is first determined by sending a flight ranging pulse and a received flight reflected pulse, and first interference information is obtained by interfering a first ranging reflected pulse based on a first wavelength and a first reference reflected pulse, and second interference information is obtained by interfering a second ranging reflected pulse based on a second wavelength and a second reference reflected pulse. Then, an error time interval is determined based on the first reference pulse and the first reference reflected pulse, so that an initial ranging distance can be determined based on the error time interval and the initial time interval, and a first synthetic wavelength is determined based on the first wavelength and the second wavelength, so that a first coefficient can be determined based on the initial ranging distance and the first synthetic wavelength. Finally, a first ranging result of the distance to be measured can be determined based on the first coefficient, the first synthetic wavelength, the first ranging interference information, the first reference interference information, the second ranging interference information, and the second reference interference information.

[0009] The solution of the present application first uses the laser frequency and its related phase changes to distinguish the flight time of the pulse from emission to reflection, then determines the low-precision distance through the flight time, then interferes the reflected pulse with the local continuous laser to obtain interference information, and synthesizes pulses of different wavelengths to obtain the corresponding synthetic wavelength, then determines the coefficient for calculating the high-precision distance through the interference information, the synthetic wavelength and the low precision, and calculates the residual distance for determining the high-precision distance through the interference information, finally calculates the high-precision distance through the coefficient, the residual distance and the synthetic wavelength, thereby improving the accuracy and precision of laser ranging, and combining the interference of laser pulses on the basis of time-of-flight ranging to achieve the ranging accuracy of the target to be measured while meeting the accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The accompanying drawings are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the present application, and together with the specification, are used to explain the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can derive other drawings based on these drawings without inventive effort.

[0011] Figure 1 It is a flowchart of a laser ranging method according to an embodiment of the present application.

[0012] Figure 21 is a schematic diagram of a measurement system for performing precision three-dimensional lidar using two frequency-stabilized lasers according to an embodiment of the present application.

[0013] Figure 3 It is a flowchart of a data storage method according to another embodiment of the present application.

[0014] Figure 4 It is a flowchart of a laser ranging method according to another embodiment of the present application.

[0015] Figure 5 Schematic diagram of a four-wavelength laser phase measurement system for coherent ranging according to an embodiment of the present application.

[0016] Figure 6 4 is a block diagram of a laser ranging device according to an embodiment of the present application.

[0017] Figure 7 It is a hardware structure diagram of an electronic device according to an embodiment of the present application.

[0018] The above-mentioned drawings have shown clear embodiments of the present invention, which will be described in more detail below. These drawings and text descriptions are not intended to limit the scope of the present invention in any way, but to illustrate the concept of the present invention to those skilled in the art through specific embodiments. DETAILED DESCRIPTION

[0019] The present invention will be further described in detail below by means of specific embodiments in conjunction with the accompanying drawings. Similar elements in different embodiments are numbered with associated similar elements. In the following embodiments, many detailed descriptions are provided to enable the present application to be better understood. However, those skilled in the art will readily appreciate that some of the features may be omitted in different circumstances, or may be replaced by other elements, materials, or methods. In some cases, some operations related to the present application are not shown or described in the specification. This is to avoid the core portion of the present application being overwhelmed by excessive descriptions, and for those skilled in the art, it is not necessary to describe these related operations in detail. They will fully understand the related operations based on the description in the specification and the general technical knowledge in the art.

[0020] In addition, the features, operations, or characteristics described in the specification may be combined in any appropriate manner to form various embodiments. Furthermore, the steps or actions in the method description may be reordered or adjusted in a manner readily apparent to those skilled in the art. Therefore, the various sequences in the specification and drawings are provided solely for the purpose of clearly describing a particular embodiment and are not intended to be mandatory, unless otherwise specified.

[0021] The serial numbers assigned to components herein, such as "first," "second," etc., are used solely to distinguish the objects being described and do not convey any sequential or technical meaning. References to "connection" and "coupling" herein, unless otherwise specified, include both direct and indirect connections (couplings).

[0022] At present, usually use time of flight (Time of Flight, TOF) measurement method to measure the distance to be measured or measure the distance to be measured by interferometry, wherein, TOF measurement method is applicable to fast long-distance measurement, but due to the limitation of time interval measurement accuracy, current TOF technology can only reach submillimeter ranging accuracy. Although interferometry can carry out high-precision ranging, when ranging distance exceeds laser half wavelength, it is necessary to complete distance measurement by continuously tracking the amplitude and phase change of interference signal, so that interferometry is time-consuming, complicated, and susceptible to external interferences such as environmental impact and temperature change, it is considered to be unsuitable for long-distance measurement. Therefore, in the prior art, always balance between precision and measurement distance, it is impossible to realize that when meeting precision, the target to be measured at a large distance is measured.

[0023] In an embodiment of the present invention, an initial time interval serving as a flight time interval is first determined by transmitting a flight ranging pulse and receiving a flight reflected pulse. A first ranging reflected pulse based on a first wavelength and a first reference reflected pulse are interfered with to obtain first interference information, and a second ranging reflected pulse based on a second wavelength and a second reference reflected pulse are interfered with to obtain second interference information. Then, an error time interval is determined based on the first reference pulse and the first reference reflected pulse, so that an initial ranging distance can be determined based on the error time interval and the initial time interval. A first composite wavelength is determined based on the first wavelength and the second wavelength, so that a first coefficient can be determined based on the initial ranging distance and the first composite wavelength. Finally, a first ranging result for the distance to be measured can be determined based on the first coefficient, the first composite wavelength, the first ranging interference information, the first reference interference information, the second ranging interference information, and the second reference interference information.

[0024] The solution of the present application first uses the laser frequency and its related phase changes to distinguish the flight time of the pulse from emission to reflection, then determines the low-precision distance through the flight time, then interferes the reflected pulse with the local continuous laser to obtain interference information, and synthesizes pulses of different wavelengths to obtain the corresponding synthetic wavelength, then determines the coefficient for calculating the high-precision distance through the interference information, the synthetic wavelength and the low precision, and calculates the residual distance for determining the high-precision distance through the interference information, finally calculates the high-precision distance through the coefficient, the residual distance and the synthetic wavelength, thereby improving the accuracy and precision of laser ranging, and combining the interference of laser pulses on the basis of time-of-flight ranging to achieve the ranging accuracy of the target to be measured while meeting the accuracy.

[0025] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically separate entities. That is, these functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices. The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily need to be executed in the order described. For example, some operations / steps may be further decomposed, while others may be combined or partially combined, so the actual execution order may vary depending on the actual situation.

[0026] See also Figure 1 , Figure 1 The laser ranging method provided by an embodiment of the present application is shown. In a specific embodiment, the laser ranging method can be applied to Figure 6 The laser distance measuring device 400 and the electronic device 500 equipped with the laser distance measuring device 400 are shown. Figure 7 ). The specific process of this embodiment will be described below. Of course, it is understandable that the method can be executed by a computer terminal with computing and processing capabilities, or other processors, or memory chips. Figure 1 The process shown is described in detail, and the laser ranging method may specifically include the following steps:

[0027] Step 110 , sending a flight ranging pulse, and receiving a flight reflected pulse that is reflected by the flight ranging pulse from the target to be measured, thereby obtaining an initial time interval from sending the transmitted flight ranging pulse to receiving the flight reflected pulse.

[0028] As a method, since laser light can be reflected by objects, the distance to an object at an unknown position can be measured by determining the time from the laser emission to the reception of the laser light reflected by the object. Furthermore, in the present application, a laser pulse can be sent to the target to be measured, and the laser pulse is used to measure the distance to the target (i.e., a flying ranging pulse). Then, the laser pulse reflected by the target to be measured (i.e., a flying reflected pulse) is received, so that the initial time interval from the sending of the flying ranging pulse to the receiving of the flying reflected pulse can be obtained.

[0029] Alternatively, the initial time interval may be determined by determining a first time stamp of sending the ranging pulse and a second time stamp of receiving the ranging pulse, for example, by subtracting the second time stamp from the first time stamp to obtain the initial time interval.

[0030] Step 120: Send a first ranging pulse of a first wavelength and a first reference pulse of the first wavelength, and receive a first ranging reflection pulse formed by the first ranging pulse being reflected from the target to be measured and a first reference reflection pulse formed by the first reference pulse being reflected from a reference surface, wherein the flight ranging pulse and the first ranging pulse are the same pulse, or the flight ranging pulse and the first ranging pulse are two different pulses sent simultaneously.

[0031] As a method, since the distance to the target to be measured is measured only by flight ranging pulses, the final distance measurement result will be inaccurate due to the limitation of the initial time interval measurement accuracy. And the distance to the target to be measured by using laser pulses based on interferometry will be unable to measure distant objects due to its test range. Therefore, the distance to the target to be measured by any single method alone will either fail to meet the required accuracy or the required range. The solution of the present application combines the interferometry method with the time-of-flight ranging method to ensure that the range is guaranteed while ensuring sufficiently high accuracy.

[0032] Optionally, to ensure the accuracy of the ranging results, a first reference pulse of the first wavelength with the same parameters may be transmitted simultaneously with the first ranging pulse of the first wavelength. The first reference pulse is a pulse used to determine the "zero point" of the time interval. After transmission, the first reference pulse is reflected by a reference surface, and a corresponding first reference reflected pulse is received. The zero point of the initial time interval determined based on the flight ranging pulse is determined by the timestamp of the transmission of the first reference pulse and the timestamp of the reception of the first reference reflected pulse.

[0033] Optionally, in order to ensure the accuracy of the final ranging result, the first ranging pulse, the first reference pulse and the flight ranging pulse can be laser pulses with the same parameters in the same pulse envelope, so that the flight ranging pulse, the first ranging pulse and the first reference pulse are sent simultaneously by sending the pulse envelope.

[0034] Optionally, to facilitate differentiation, the first ranging pulse, the flight ranging pulse and the first reference pulse may not be placed in the same pulse envelope, but may be laser pulses with the same parameters in different pulse envelopes sent simultaneously.

[0035] Step 130 , sending a second ranging pulse of a second wavelength and a second reference pulse of a second wavelength, and receiving a second ranging reflected pulse reflected by the second ranging pulse from the target to be measured and a second reference reflected pulse reflected by the second reference pulse from the reference surface.

[0036] As a method, the single-wavelength interferometry ranging method calculates the optical path difference by measuring the phase difference between the target light and the reference light to obtain the ranging result of the target to be measured. However, since the ranging method based on the phase difference has high accuracy and the phase difference is periodic, that is, it takes one wavelength as a period, the part of the ranging result indicating the distance change representing the single wavelength is less than half a wavelength cannot distinguish the distance that differs by an integer number of wavelengths, which leads to ranging ambiguity in the final ranging result through single-wavelength interferometry ranging. Therefore, by adding laser pulses of different wavelengths, an equivalent longer wavelength can be determined, and then the ranging result can be determined by this equivalent longer wavelength, thereby avoiding the ranging ambiguity caused by single-wavelength interferometry ranging, breaking through the limitation of single wavelength and half a wavelength, and improving the measurement range and measurement accuracy of the ranging result.

[0037] Alternatively, a tunable laser can be used to simultaneously transmit a first ranging pulse of a first wavelength and a second ranging pulse of a second wavelength, thereby ensuring that the first ranging pulse and the second ranging pulse can be transmitted simultaneously. Alternatively, multiple fixed-wavelength lasers can be used to simultaneously transmit the corresponding first ranging pulse of the first wavelength and the second ranging pulse of the second wavelength. Alternatively, an optical frequency comb can be used to simultaneously transmit the first ranging pulse of the first wavelength and the second ranging pulse of the second wavelength. To ensure multi-wavelength interferometry, the first wavelength and the second wavelength have a certain frequency difference.

[0038] Step 140: interfere the first ranging reflected pulse with the first local continuous wave to obtain first ranging interference information, and interfere the first reference reflected pulse with the first local continuous wave to obtain first reference interference information, wherein the first local continuous wave and the first ranging pulse belong to the same light source.

[0039] As a method, after receiving the first ranging reflection pulse after the first ranging pulse is reflected by the target to be measured, in order to obtain the corresponding interference fringes, the first local continuous wave can be pulse-modulated to obtain the first ranging pulse and the first reference pulse, thereby ensuring that the first local continuous wave and the first ranging pulse belong to the same light source. However, since the phase change of the high-frequency optical signal cannot be directly demodulated, the heterodyne signal can inherit all the phase change information of the signal light. Therefore, the first ranging reflection pulse and the first local continuous wave with the same wavelength can be interfered to obtain the first ranging interference information, and the first reference reflection pulse and the first local continuous wave can be interfered to obtain the first reference interference information. Then, the corresponding phase information of the first ranging interference information and the first reference interference information can be determined by heterodyne detection.

[0040] Alternatively, a continuous-wave, single-frequency laser with good coherence can be used as the light source. Its output light is split into two paths, one as local light, and the other shaped into a corresponding pulse sequence by an acousto-optic modulator (AOM) or electro-optic modulator. These pulses are then directed to the target via a reference plane, and the pulses reflected (or scattered) from the reference plane and the target are mixed with the local continuous-wave light. As a result, time-varying heterodyne interference fringes are formed within the pulse envelope. These fringes contain not only peak intensity information but also frequency and phase information. Thus, upon receiving the reference reflected pulse reflected from the reference plane and the ranging reflected pulse reflected from the target, the heterodyne frequency of the interference fringes and the phase difference between the reference pulse and the ranging pulse can be obtained.

[0041] Step 150: interfere the second ranging reflected pulse with the second local continuous wave to obtain second ranging interference information, and interfere the second reference reflected pulse with the second local continuous wave to obtain second reference interference information, wherein the second local continuous wave and the second ranging pulse belong to the same light source.

[0042] As a method, in order to improve the precision and accuracy of the ranging results, the second ranging reflection pulse and the second reference reflection pulse corresponding to the second ranging pulse and the second reference pulse having a second wavelength different from the first ranging pulse and the first reference pulse having the first wavelength are used to interfere with the second local continuous wave to obtain corresponding interference fringes, so that the corresponding second ranging interference information and the second reference interference information can be obtained by analyzing the corresponding interference fringes.

[0043] Step 160: Determine an error time interval based on the first reference pulse and the first reference reflected pulse.

[0044] As a method, since determining the ranging result by the initial time interval corresponding to the flight ranging pulse will lead to an error in the initial time interval due to the unknown ranging zero point, which in turn leads to an increase in the error of the ranging result, the ranging zero point can be first determined based on the first reference pulse and the first reference reflected pulse, that is, the error time interval is determined.

[0045] Optionally, the error time interval may be determined by determining a sending timestamp of the first reference reflected pulse and a receiving timestamp of the first reference reflected pulse.

[0046] Step 170: Determine an initial ranging distance according to the initial time interval and the error time interval.

[0047] As one approach, after determining the initial time interval and the error time interval, the actual time interval can be determined based on the initial time interval and the error time interval, and then the initial ranging distance can be determined based on the actual time interval and the speed of light. For example, the formula D = c / 2*(T-t0) can be used, where D is the initial ranging distance, T is the initial time interval, and t0 is the error time interval.

[0048] Step 180: Determine a first composite wavelength based on the first wavelength and the second wavelength, and determine a first coefficient based on the initial ranging distance and the first composite wavelength, wherein the first coefficient represents a multiple of half of the first composite wavelength contained in the distance to be measured corresponding to the target to be measured, and the first coefficient is an integer.

[0049] As a way to avoid the problem that the ranging result of the target to be measured is not accurate due to the ranging result determined by a single wavelength laser ranging pulse, but multiple different wavelengths still have ranging ambiguity, resulting in inaccurate ranging results, laser ranging pulses of different wavelengths can be synthesized to obtain a ranging pulse with a longer wavelength that is equivalent to the laser ranging pulse of a different wavelength. Based on the synthesized equivalent ranging pulse with a longer wavelength, the single wavelength phase difference or ambiguity in the ranging result determined by the single wavelength laser ranging pulse can be eliminated.

[0050] Alternatively, the wavelength difference and the wavelength product may be determined based on the first wavelength and the second wavelength, and then the first composite wavelength may be determined by the wavelength difference and the wavelength product. 12 =1 / 2*Λ 12 To determine the first synthetic wavelength, where Λ 12 is the first composite wavelength, which can be expressed by the formula Λ 12 =λ1λ2 / (λ1-λ2), where λ1 is the first wavelength and λ2 is the second wavelength.

[0051] As a way to determine the distance measurement result of the target based on the interferometric ranging method, the formula Therefore, it can be known that if M and The absolute distance between the reference object and the target can be directly obtained with high precision by using the value of It can be determined by analyzing the first ranging interference information and the first reference interference information. However, M represents the multiple of half the wavelength contained in the distance to be measured corresponding to the target to be measured. For large distances (usually tens of meters or longer), the M value is usually a very large integer. Accurate distance measurement requires determining the M value. After determining the first synthetic wavelength, its corresponding formula can be changed to Therefore, it is necessary to determine the value of M1 in order to determine the distance measurement result of the target to be measured. Since the first coefficient represents the multiple of half of the first synthetic wavelength contained in the distance to be measured corresponding to the target to be measured, combined with the formula and formula L 12 =1 / 2*Λ 12 , we can know that: M1=[D / L 12 ], where D is the initial ranging distance, [D / L 12 ] indicates D / L 12 The value is rounded.

[0052] Step 190 : Determine a first ranging result of the distance to be measured according to the first coefficient, the first synthetic wavelength, the first ranging interference information, the first reference interference information, the second ranging interference information, and the second reference interference information.

[0053] As a way, since there is a certain frequency difference and accuracy difference between the first wavelength and the second wavelength, in order to avoid errors in the ranging results determined based on the first synthetic wavelength due to the accuracy difference between the first wavelength and the second wavelength, and in order to reduce the inaccurate ranging results caused by the errors, an accuracy value for reducing the error can be determined based on the first ranging interference information, the first reference interference information, the first wavelength and the second wavelength, and then the first ranging result is determined based on the accuracy value, the first coefficient and the first synthetic wavelength.

[0054] Alternatively, long-distance three-dimensional coordinate measurement with sub-millimeter accuracy can be achieved by using a first wavelength and a second wavelength with frequency and precision differences. For example, distance measurement can be performed by using two frequency-stabilized lasers to carry out precision three-dimensional laser radar. Figure 2As shown, two wavelength-stabilized lasers are used, with wavelengths of λ1 = 1563.00 nm and λ2 = 1563.064 nm, respectively. The frequency difference between the two lasers is approximately 8 GHz, resulting in a composite wavelength of 19,086,476 nm (approximately 19 mm). The frequency difference between the two lasers remains stable. Both lasers are continuous light and are split into two paths: one path serves as the local continuous wave for coherent detection, and the other is combined via a fiber coupler. The combined continuous wave lasers are then transformed into pulses with a pulse width of 20 ns and a pulse frequency of 100 kHz by an acousto-optic modulator (AOM). The frequency shift of the AOM is 200 MHz. After being amplified by an erbium-doped fiber amplifier (EDFA), the laser pulses containing the two wavelengths are directed through a circulator and a fiber collimator to a two-dimensional laser galvanometer, which can scan the collimated beam in two dimensions, with scanning angles of -19 to 19 degrees in both the horizontal and vertical directions (a full angle of approximately 38 degrees). The target to be measured is a three-dimensional object with varying heights. Different locations on the object have different heights, resulting in different measured distances. The surface of the fiber collimator has a weak reflectance, which serves as a reference for distance measurement. By controlling the two-dimensional laser galvanometer to scan in a specific array, distances can be scanned at different locations on the target. This distance, combined with the scanning angle, constitutes the 3D LiDAR test result.

[0055] The laser emitted by the pulse is reflected from the reference surface and target point of the collimator. The laser is also collected by the collimator and then passes through a circulator and a beam splitter constructed by a fiber coupler. It is divided into two paths and enters two 2x2 fiber couplers respectively. They are mixed with their respective local continuous lasers to obtain their own interference fringes. The interference fringes after mixing are received by two balanced detectors and converted into two electrical signals. The electrical signals are processed in real time by a high-speed signal sampling and processing circuit (DSP). The signal sampling bandwidth of the circuit board is 2GHz.

[0056] By processing two electrical signals, determining a first composite wavelength based on the first and second wavelengths, and analyzing the resulting interference fringes after mixing, the corresponding interference information is obtained. This allows the distance to the corresponding reflection point to be determined based on the first composite wavelength and the corresponding interference information. This allows precise measurement of the distance to each reflection point, and combined with the scanning angle array, the three-dimensional coordinate information of the target can be constructed. The two lasers used have a laser frequency difference of 8 GHz, corresponding to a ranging accuracy of approximately 0.1 mm.

[0057] In an embodiment of the present application, an initial time interval serving as a flight time interval is first determined by transmitting a flight ranging pulse and receiving a flight reflected pulse, and first interference information is obtained by interfering a first ranging reflected pulse based on a first wavelength with a first reference reflected pulse, and second interference information is obtained by interfering a second ranging reflected pulse based on a second wavelength with a second reference reflected pulse. Then, an error time interval is determined based on the first reference pulse and the first reference reflected pulse, so that an initial ranging distance can be determined based on the error time interval and the initial time interval. A first synthetic wavelength is determined based on the first wavelength and the second wavelength, so that a first coefficient can be determined based on the initial ranging distance and the first synthetic wavelength. Finally, a first ranging result for the distance to be measured can be determined based on the first coefficient, the first synthetic wavelength, the first ranging interference information, the first reference interference information, the second ranging interference information, and the second reference interference information.

[0058] The solution of the present application first uses the laser frequency and its related phase changes to distinguish the flight time of the pulse from emission to reflection, then determines the low-precision distance through the flight time, then interferes the reflected pulse with the original local continuous laser to obtain interference information, and synthesizes pulses of different wavelengths to obtain the corresponding synthetic wavelength, then determines the coefficient for calculating the high-precision distance through the interference information, the synthetic wavelength and the low precision, and calculates the residual distance for determining the high-precision distance through the interference information, finally calculates the high-precision distance through the coefficient, the residual distance and the synthetic wavelength, thereby improving the accuracy and precision of laser ranging, and combining the interference of laser pulses on the basis of time-of-flight ranging to achieve the ranging accuracy of the target to be measured while meeting the accuracy.

[0059] See also Figure 3 , Figure 3 The laser ranging method provided by an embodiment of the present application is shown below. Figure 3 The process shown is described in detail, and the laser ranging method may specifically include the following steps:

[0060] Step 201 : sending a flight ranging pulse, and receiving a flight reflected pulse which is reflected by a target to be measured, so as to obtain an initial time interval from sending the transmitted flight ranging pulse to receiving the flight reflected pulse.

[0061] Step 202: Send a first ranging pulse of a first wavelength and a first reference pulse of the first wavelength, and receive a first ranging reflection pulse formed by the first ranging pulse being reflected from the target to be measured and a first reference reflection pulse formed by the first reference pulse being reflected from a reference surface, wherein the flight ranging pulse and the first ranging pulse are the same pulse, or the flight ranging pulse and the first ranging pulse are two different pulses sent simultaneously.

[0062] Step 203 , sending a second ranging pulse of a second wavelength and a second reference pulse of a second wavelength, and receiving a second ranging reflected pulse reflected by the second ranging pulse from the target to be measured and a second reference reflected pulse reflected by the second reference pulse from the reference surface.

[0063] Step 204: interfere the first ranging reflected pulse with the first local continuous wave to obtain first ranging interference information, and interfere the first reference reflected pulse with the first local continuous wave to obtain first reference interference information, wherein the first local continuous wave and the first ranging pulse belong to the same light source.

[0064] Step 205: interfere the second ranging reflected pulse with the second local continuous wave to obtain second ranging interference information, and interfere the second reference reflected pulse with the second local continuous wave to obtain second reference interference information, wherein the second local continuous wave and the second ranging pulse belong to the same light source.

[0065] Step 206: Determine an error time interval based on the first reference pulse and the first reference reflected pulse.

[0066] Step 207: Determine an initial ranging distance according to the initial time interval and the error time interval.

[0067] Step 208: Determine a first composite wavelength based on the first wavelength and the second wavelength, and determine a first coefficient based on the initial ranging distance and the first composite wavelength, wherein the first coefficient represents a multiple of half of the first composite wavelength contained in the measured distance corresponding to the target to be measured, and the first coefficient is an integer.

[0068] The specific step descriptions of steps 201 to 208 can be found in steps 110 to 180 and will not be repeated here.

[0069] Step 209 : determining a first phase difference according to the first ranging interference information and the first reference interference information, and determining a second phase difference according to the second ranging interference information and the second reference interference information.

[0070] As a method, after obtaining the first ranging interference information and the first reference interference information, in order to ensure the accuracy of the ranging result of the determined target to be measured, it is necessary to determine the accuracy difference corresponding to the first synthetic wavelength, so that the first phase difference and the second phase difference can be determined by performing signal processing on the first ranging interference information and the first reference interference information respectively.

[0071] Optionally, since the first ranging pulse is a laser pulse obtained by pulse-modulating the first local continuous wave, and has a certain frequency difference with the first local continuous wave, the corresponding interference fringes formed will integrate the corresponding frequency difference and phase change information. Then, the first ranging phase and the first reference phase can be obtained by performing heterodyne detection on the first ranging interference information, and then the first ranging phase and the first reference phase are subtracted to obtain the first phase difference. in, is the first phase difference, is the first ranging phase, is the first reference phase. Similarly, since the second ranging pulse is a laser pulse obtained by pulse modulation of the second local continuous wave, and there is a certain frequency gap between it and the second local continuous wave, the corresponding interference fringes formed will integrate the corresponding frequency gap and phase change information. Then, the second ranging phase and the second reference phase can be obtained by performing heterodyne detection on the second ranging interference information, and then the second ranging phase and the second reference phase can be subtracted to obtain the second phase difference. That is, in, is the second phase difference, is the second ranging phase, is the second reference phase.

[0072] Step 210 : determining a first residual distance according to the first phase difference, the second phase difference, and the first synthesized wavelength, wherein the first residual distance represents a remaining distance beyond a multiple of the first synthesized wavelength.

[0073] As a method, after determining the first phase difference and the second phase difference, the first phase difference, the second phase difference and the first composite wavelength can be used to determine the remaining distance other than the multiples of the first composite wavelength corresponding to the distance to be measured during ranging, so as to ensure the accuracy of the ranging result based on the remaining distance. Optionally, the formula To determine the first residual distance, where l 12 is the first residual distance.

[0074] Step 211: Determine a first distance measurement result according to the first coefficient, the first synthetic wavelength, and the first residual distance.

[0075] As a method, after determining the first coefficient, the first synthetic wavelength and the first residual distance, the formula d1 = M1 * L can be used. 12 +l 12 To determine the first distance measurement result, wherein the first residual distance corresponds to the error data when the first distance measurement result is determined using the first synthetic wavelength, for example, 1%, so its corresponding error range is less than 1% of 20 mm, which is approximately 0.2 mm.

[0076] In this embodiment, a first phase difference is first determined based on the first ranging interference information and the first reference interference information, and a second phase difference is determined based on the second ranging interference information and the second reference interference information. In this way, a first residual distance representing the remaining distance beyond the multiple of the first synthetic wavelength can be determined based on the first phase difference, the second phase difference, and the first synthetic wavelength. Finally, a first ranging result can be determined based on the determined first coefficient, the first synthetic wavelength, and the first residual distance, thereby ensuring the accuracy of the first ranging result.

[0077] See also Figure 4 , Figure 4 The laser ranging method provided by an embodiment of the present application is shown below. Figure 4 The process shown is described in detail, and the laser ranging method may specifically include the following steps:

[0078] Step 301: While transmitting a first ranging pulse of a first wavelength, a third ranging pulse and a third reference pulse of a third wavelength, and a fourth ranging pulse and a fourth reference pulse of a fourth wavelength are respectively transmitted, and a third ranging reflected pulse reflected by the third ranging pulse from the target to be measured and a fourth ranging reflected pulse reflected by the fourth ranging pulse from the target to be measured are received, as well as a third reference reflected pulse reflected by the third reference pulse from a reference surface and a fourth reference reflected pulse reflected by the fourth reference pulse from the reference surface are received, wherein there is a frequency difference between the third wavelength and the first wavelength, and there is a frequency difference between the fourth wavelength and the first wavelength.

[0079] As a way, due to the demand for accuracy of the ranging results, when the accuracy is required to be higher, comprehensive ranging can be performed by combining laser ranging pulses of more wavelengths. Therefore, while emitting a first ranging pulse of the first wavelength, a third ranging pulse and a third reference pulse of the third wavelength can be sent respectively, as well as a fourth ranging pulse and a fourth reference pulse of the fourth wavelength can be sent.

[0080] Optionally, in order to ensure that the ranging results can be further refined based on the laser pulses of the third wavelength and the laser pulses of the fourth wavelength, the third wavelength and the fourth wavelength can be set to have a frequency difference with the first pulse, so that the subsequent mixing of the third wavelength and the fourth wavelength with the first wavelength can be carried out accurately.

[0081] Optionally, by mixing a laser pulse of a first wavelength, a laser pulse of a second wavelength, a laser pulse of a third wavelength and a laser pulse of a fourth wavelength with a certain frequency difference in the same pulse envelope, it is possible to simultaneously send laser pulses of four wavelengths by emitting one pulse envelope.

[0082] Optionally, in order to achieve a step-by-step improvement in the accuracy of the ranging results, the accuracy corresponding to the first ranging pulse, the second ranging pulse, the third ranging pulse and the fourth ranging pulse can be set to gradually increase in sequence, so that the accuracy of the flight ranging pulse can be gradually improved to the accuracy of a single laser pulse.

[0083] Optionally, in order to facilitate distinction, the laser pulse of the first wavelength, the flight ranging pulse of the first wavelength, the laser pulse of the second wavelength, the laser pulse of the third wavelength and the laser pulse of the first wavelength may not be placed in the same pulse envelope, but laser pulses with corresponding parameters in different pulse envelopes may be sent simultaneously by different pulse transmitters.

[0084] Step 302: interfere the third ranging reflected pulse with the third local continuous wave to obtain third ranging interference information, and interfere the third reference reflected pulse with the third local continuous wave to obtain third reference interference information, wherein the third local continuous wave and the third ranging pulse belong to the same light source.

[0085] As a method, since the ranging result of the target to be measured is comprehensively determined by multi-wavelength cascade, the ranging result can be refined step by step through laser pulses of different wavelengths, thereby ensuring that the accuracy of the flight pulse ranging can be associated with the final ranging accuracy, thereby ensuring the accuracy of the ranging result. Therefore, the third ranging reflected pulse and the third local continuous wave can be interfered to obtain third ranging interference fringes, and the third ranging interference information can be obtained by analyzing the third ranging interference fringes. Similarly, the third reference reflected pulse and the third local continuous wave are interfered to obtain third reference interference fringes, and the third reference interference information is obtained by interfering the third reference interference fringes.

[0086] Step 303: interfere the fourth ranging reflected pulse with the fourth local continuous wave to obtain fourth ranging interference information, and interfere the fourth reference reflected pulse with the fourth local continuous wave to obtain fourth reference interference information, wherein the fourth local continuous wave and the fourth ranging pulse belong to the same light source.

[0087] As a method, the fourth ranging reflection pulse and the fourth local continuous wave are interfered with to obtain fourth ranging interference fringes, and the fourth ranging interference information is obtained by analyzing the fourth ranging interference fringes. Similarly, the fourth reference reflected pulse and the fourth local continuous wave are interfered with to obtain fourth reference interference fringes, and the fourth reference interference information is obtained by interfering with the fourth reference interference fringes.

[0088] Step 304 : determining a second synthesized wavelength according to the first wavelength and the third wavelength, wherein the second synthesized wavelength has a higher precision than the first synthesized wavelength.

[0089] As a way, since the wavelength of the synthetic wavelength obtained by mixing wavelengths with frequency differences is much larger than the original wavelength with frequency differences, the unambiguous range corresponding to the synthetic wavelength is much larger than the unambiguous range of a single wavelength. Therefore, when measuring distance changes, absolute distances or large step heights that exceed the unambiguous range of a single wavelength, the synthetic wavelength can be used to obtain measurement results directly and without ambiguity. In this way, by combining synthetic wavelengths of different scales and single wavelength phases, hierarchical measurements from large-scale coarse measurements to local high-precision precise measurements can be achieved, thereby ensuring the accuracy of the ranging results, thereby ensuring the accuracy of the ranging results.

[0090] Optionally, in order to determine a ranging result with higher accuracy than the first ranging result, the first wavelength and the third wavelength can be mixed to obtain an equivalent wavelength that is longer than the first wavelength and the third wavelength. The equivalent wavelength does not have the ambiguous distance in the ranging by the first wavelength or the third wavelength, so the accuracy is higher than the ranging by only the first wavelength or the third wavelength.

[0091] Optionally, in order to ensure that the ranging results of the target to be measured become more accurate step by step and its accuracy increases accordingly, the frequency difference between the first wavelength and the third wavelength can be set to be greater than the frequency difference between the first wavelength and the second wavelength, thereby ensuring that the accuracy of the second synthetic wavelength is greater than the accuracy of the first synthetic wavelength.

[0092] Optionally, the wavelength difference and the wavelength product may be determined based on the first wavelength and the third wavelength, and then the second composite wavelength may be determined by the wavelength difference and the wavelength product. Optionally, the second composite wavelength may be determined by the formula L 13 =1 / 2*Λ 13 To determine the second synthetic wavelength, where Λ 13 is the second composite wavelength, which can be expressed by the formula Λ 13 =λ1λ3 / (λ1-λ3), where λ1 is the first wavelength and λ3 is the third wavelength.

[0093] Step 305 : determining a second coefficient according to the first distance measurement result and the second synthetic wavelength, wherein the second coefficient represents a multiple of half of the second synthetic wavelength contained in the distance to be measured, and the second coefficient is an integer.

[0094] As a method, when the first distance measurement result and the second synthetic wavelength are obtained, in order to determine the second distance measurement result determined based on the second synthetic wavelength, the second coefficient corresponding to the second synthetic wavelength can be determined first, so that the second distance measurement result corresponding to the second synthetic wavelength can be determined based on the second coefficient. Since the second coefficient represents the multiple of half of the second synthetic wavelength contained in the distance to be measured corresponding to the target to be measured, combined with the formula and formula L13 =1 / 2*Λ 13 , we can know that: M2=[d1 / L 13 ], where d1 is the first distance measurement result, [d1 / L 13 ] indicates d1 / L 13 Optionally, since the first distance measurement result is d1=M1*L 12 +l 12 Therefore, the second coefficient can also be M2=[(M1*L 12 +l 12 ) / L 13 ].

[0095] Step 306: Determine a third phase difference based on the third ranging interference information and the third reference interference information, and determine a second residual distance corresponding to the distance to be measured based on the third phase difference, the first phase difference, and the second synthetic wavelength, wherein the second residual distance represents a remaining distance beyond a multiple of half the second synthetic wavelength.

[0096] As a way, since there is a certain frequency difference and accuracy difference between the first wavelength and the third wavelength, in order to avoid errors in the ranging results determined based on the second synthetic wavelength due to the accuracy difference between the first wavelength and the third wavelength, thereby reducing the inaccurate ranging results caused by the error, the accuracy value for reducing the error can be determined according to the third ranging interference information, the third reference interference information, the first wavelength and the third wavelength, and then the second ranging result is determined based on the accuracy value, the second coefficient and the second synthetic wavelength.

[0097] Optionally, after obtaining the third ranging interference information and the third reference interference information, in order to ensure the accuracy of the ranging result of the determined target to be measured, it is necessary to determine the accuracy difference corresponding to the second synthetic wavelength, so that the third phase difference can be determined by performing heterodyne interference on the third ranging interference information and the third reference interference information respectively, and the second residual distance corresponding to the distance to be measured is determined based on the third phase difference, the first phase difference and the second synthetic wavelength.

[0098] Optionally, since the third ranging pulse is a laser pulse obtained by pulse-modulating the third local continuous wave, and has a certain frequency difference with the third local continuous wave, the corresponding interference fringes formed will integrate the corresponding frequency difference and phase change information. Then, the third ranging phase and the third reference phase can be obtained by performing heterodyne detection on the third ranging interference information, and then the third ranging phase and the third reference phase are subtracted to obtain the third phase difference. in, is the third phase difference, is the third ranging phase, is the third reference phase.

[0099] Optionally, after determining the first phase difference and the third phase difference, the first phase difference, the third phase difference and the second composite wavelength can be used to determine the remaining distance other than the multiples of the second composite wavelength corresponding to the distance to be measured during ranging, so as to ensure the accuracy of the ranging result based on the remaining distance. Optionally, the formula To determine the second residual distance, where l 13 is the second residual distance.

[0100] Step 307: Determine a second ranging result according to the second coefficient, the second synthesized wavelength, and the second residual distance, wherein the second ranging result has a higher accuracy than the first ranging result.

[0101] As a method, after determining the second coefficient, the second synthetic wavelength and the second residual distance, the formula d2=M2*L can be used. 13 +l 13 To determine the second distance measurement result, wherein the second residual distance corresponds to the error data when the second distance measurement result is determined using the second synthetic wavelength. Since the second coefficient can also be M2=[(M1*L 12 +l 12 ) / L 13 ], therefore, the second distance measurement result can also be d2=[(M1*L 12 +l 12 ) / L 13 ]*L 13 +l 13 .

[0102] Optionally, in order to ensure that the accuracy of the ranging results can be gradually increased, the accuracy of the ranging pulses, reference pulses, and local continuous waves corresponding to the second wavelength can be set to be lower than the accuracy of the ranging pulses, reference pulses, and local continuous waves corresponding to the third wavelength, so that the accuracy of the second ranging result determined is higher than the accuracy of the first ranging result.

[0103] Step 308 : Determine a third synthesized wavelength according to the first wavelength and the fourth wavelength, wherein the accuracy of the third synthesized wavelength is higher than that of the second synthesized wavelength.

[0104] As a way, in order to determine a ranging result with higher accuracy than the second ranging result, the first wavelength and the fourth wavelength can be mixed to obtain an equivalent wavelength that is longer than the first wavelength and the fourth wavelength. The equivalent wavelength does not have the ambiguous distance in the ranging by the first wavelength or the fourth wavelength, so the accuracy is higher than the accuracy of ranging by only the first wavelength or the fourth wavelength.

[0105] Optionally, in order to ensure that the ranging results of the target to be measured become more accurate step by step and its accuracy increases accordingly, the frequency difference between the first wavelength and the fourth wavelength can be set to be greater than the frequency difference between the first wavelength and the third wavelength, thereby ensuring that the accuracy of the third synthetic wavelength is greater than the accuracy of the second synthetic wavelength.

[0106] Optionally, the wavelength difference and the wavelength product may be determined based on the first wavelength and the fourth wavelength, and then the third composite wavelength may be determined by the wavelength difference and the wavelength product. Optionally, the third composite wavelength may be determined by the formula L 14 =1 / 2*Λ 14 To determine the third synthetic wavelength, where Λ 14 is the third composite wavelength, which can be expressed by the formula Λ 14 =λ1λ4 / (λ1-λ4), where λ1 is the first wavelength and λ4 is the fourth wavelength.

[0107] Step 309 : determining a third coefficient according to the second distance measurement result and the third synthetic wavelength, wherein the third coefficient represents a multiple of half of the third synthetic wavelength contained in the distance to be measured, and the third coefficient is an integer.

[0108] As a method, when the first distance measurement result and the third synthetic wavelength are obtained, in order to determine the third distance measurement result determined based on the third synthetic wavelength, the third coefficient corresponding to the third synthetic wavelength can be determined first, so that the third distance measurement result corresponding to the third synthetic wavelength can be determined based on the third coefficient. Since the third coefficient represents the multiple of half of the third synthetic wavelength contained in the distance to be measured corresponding to the target to be measured, combined with the formula and formula L 14 =1 / 2*Λ 14 , we can know that: M3=[d2 / L 14 ], where d2 is the second distance measurement result, [d2 / L 14 ] indicates d2 / L 14 Optionally, since the second distance measurement result is d2=M2*L 13 +l 13 Therefore, the third coefficient can also be M3=[(M2*L 13 +l 13 ) / L 14 ], since M2=[(M1*L 12 +l 12 ) / L 13 ], therefore, the third coefficient can also be M3=[([(M1*L 12 +l 12 ) / L 13 ]*L 13 +l 13 ) / L 14 ].

[0109] Step 310: Determine a fourth phase difference based on the fourth ranging interference information and the fourth reference interference information, and determine a third residual distance corresponding to the measured distance based on the fourth phase difference, the first phase difference, and the third synthetic wavelength, wherein the third residual distance represents a distance other than a multiple of half the third synthetic wavelength.

[0110] As a way, since there is a certain frequency difference and accuracy difference between the first wavelength and the fourth wavelength, in order to avoid errors in the ranging results determined based on the third synthetic wavelength due to the accuracy difference between the first wavelength and the fourth wavelength, thereby reducing the inaccurate ranging results caused by the errors, an accuracy value for reducing the error can be determined according to the fourth ranging interference information, the fourth reference interference information, the first wavelength and the fourth wavelength, and then the second ranging result is determined based on the accuracy value, the third coefficient and the third synthetic wavelength.

[0111] Optionally, after obtaining the fourth ranging interference information and the fourth reference interference information, in order to ensure the accuracy of the ranging result of the determined target to be measured, it is necessary to determine the accuracy difference corresponding to the third synthetic wavelength, so that the fourth phase difference can be determined by performing heterodyne interference on the fourth ranging interference information and the fourth reference interference information respectively, and the third residual distance corresponding to the distance to be measured is determined based on the fourth phase difference, the first phase difference and the third synthetic wavelength.

[0112] Optionally, since the fourth ranging pulse is a laser pulse obtained by pulse-modulating the third local continuous wave and has a certain frequency difference with the fourth local continuous wave, the corresponding interference fringes formed will integrate the corresponding frequency difference and phase change information. Then, the fourth ranging phase and the fourth reference phase can be obtained by performing heterodyne detection on the fourth ranging interference information, and then the fourth ranging phase and the fourth reference phase are subtracted to obtain the fourth phase difference. in, is the fourth phase difference, is the fourth ranging phase, is the fourth reference phase.

[0113] Optionally, after determining the fourth phase difference and the first phase difference, the first phase difference, the fourth phase difference and the third composite wavelength can be used to determine the remaining distance other than the multiples of the third composite wavelength corresponding to the distance to be measured during ranging, so as to ensure the accuracy of the ranging result based on the remaining distance. Optionally, the formula To determine the third residual distance, where l 14 is the third residual distance.

[0114] Step 311: Determine a third ranging result according to the third coefficient, the third synthetic wavelength, and the third residual distance, wherein the accuracy of the third ranging result is higher than that of the second ranging result.

[0115] As a method, after determining the third coefficient, the third synthetic wavelength and the third residual distance, the formula d3 = M3 * L can be used. 14 +l 14 To determine the third distance measurement result, wherein the third residual distance corresponds to the error data when the third distance measurement result is determined using the third synthetic wavelength. Since the third coefficient can also be M3 = [(M2*L 13 +l 13 ) / L 13 ], therefore, the third distance measurement result can also be d3=[(M2*L 13 +l 13 ) / L 13 ]*L 14 +l 14 , and because M2=[(M1*L 12 +l 12 ) / L 13 ], so the third distance measurement result can also be d3=[([(M1*L 12 +l 12 ) / L 13 ]*L 13 +l 13 ) / L 13 ]*L 14 +l 14 .

[0116] Optionally, in order to ensure that the accuracy of the ranging results can be gradually increased, the accuracy of the ranging pulses, reference pulses, and local continuous waves corresponding to the third wavelength can be set to be lower than the accuracy of the ranging pulses, reference pulses, and local continuous waves corresponding to the fourth wavelength, so that the accuracy of the third ranging result determined is higher than the accuracy of the second ranging result.

[0117] Step 312: Determine a fourth coefficient based on the first wavelength and the third distance measurement result, wherein the fourth coefficient represents a multiple of half of the first wavelength contained in the distance to be measured, and the fourth coefficient is an integer.

[0118] As a way, in order to align the accuracy of the ranging result of the target to be measured with the accuracy of a single laser pulse, on the basis of determining the third ranging result, the first wavelength is combined to further determine the fourth coefficient used to determine the fourth ranging result. In this way, the accuracy can be determined by the fourth coefficient to align the accuracy with the first wavelength with the highest accuracy in the laser pulse, thereby ensuring the accuracy of the fourth ranging result.

[0119] Optionally, you can combine the formula and formula L λ =1 / 2*λ1, we can know that: M4=[d3 / L λ ], where d3 is the third distance measurement result, [d3 / L λ ] indicates d3 / L λ Optionally, since the third distance measurement result is d3=M3*L 14 +l 14 Therefore, the fourth coefficient can also be M4=[(M3*L 14 +l 14 ) / L λ ], since M3=[(M2*L 13 +l 13 ) / L 13 ], so the fourth coefficient can also be M4=[{[(M2*L 13 +l 13 ) / L 13 ]*L 14 +l 14} / L λ ], and because M2=[(M1*L 12 +l 12 ) / L 13 ], so the fourth coefficient can also be M4=[{[([(M1*L 12 +l 12 ) / L 13 ]*L 13 +l 13 ) / L 13 ]*L 14 +l 14} / L λ ].

[0120] Step 313: Determine a fourth residual distance based on the first wavelength and the first phase difference, and determine a fourth ranging result based on the fourth coefficient, the first wavelength, and the fourth residual distance, wherein the fourth residual distance represents the remaining distance beyond a multiple of half the first wavelength, and the accuracy of the fourth ranging result is higher than that of the third ranging result.

[0121] As a way, in order to avoid the inaccurate ranging result of the target to be measured determined based on the fuzzy distance due to the existence of a certain fuzzy distance in the first wavelength, an accuracy value for reducing the error can be determined according to the first wavelength and the first phase difference, and then the fourth ranging result is determined based on the accuracy value, the fourth coefficient and the first wavelength.

[0122] Optionally, the first phase difference and the first wavelength may be used to determine the remaining distance other than the multiple of the first wavelength corresponding to the distance to be measured during ranging, so that the accuracy of the ranging result can be ensured based on the remaining distance. Optionally, the formula To determine the fourth residual distance, where l λ is the fourth residual distance.

[0123] Optionally, after determining the fourth coefficient and the fourth residual distance, the formula d4=M4*L can be used. λ +l λ To determine the fourth distance measurement result, wherein the fourth residual distance corresponds to the error data when the third distance measurement result is determined using the first wavelength. Since the fourth coefficient can also be M4=[(M3*L 14 +l 14 ) / L λ ], therefore, the fourth distance measurement result can also be d4=[(M3*L 14 +l 14 ) / L λ ]*L λ +l λ , and because M3=[(M2*L 13 +l 13 ) / L 13 ], so the fourth distance measurement result can also be d4=[([(M2*L 13 +l 13 ) / L 13 ]*L 14 +l 14 ) / L λ ]*L λ +l λ , and since M2=[(M1*L 12 +l 12 ) / L 13 ], and the fourth distance measurement result can also be d4=[([([(M1*L 12 +l 12 ) / L 13 ]*L 13 +l 13 ) / L 13 ]*L 14 +l 14 ) / L λ ]*L λ +l λ .

[0124] Optionally, in order to ensure that the accuracy of the ranging results can be gradually increased, the accuracy of the ranging pulses, reference pulses and local continuous waves corresponding to the first wavelength can be set to be higher than the accuracy of the ranging pulses, reference pulses and local continuous waves corresponding to other wavelengths, so that the accuracy of the fourth ranging result determined based on the first wavelength is the highest.

[0125] As a method, a 4-wavelength laser phase measurement system for coherent ranging can be used to perform high-precision ranging on the target to be measured, thereby obtaining a high-precision ranging result, such as Figure 5 As shown in the figure, a precision laser ranging system is shown, which is composed of four groups of lasers with different wavelengths. The wavelengths used are λ1 = 1563.00nm, λ2 = 1535.60nm, λ3 = 1561.40nm, and λ4 = 1563.064nm. The corresponding synthetic wavelengths are the first synthetic wavelength L 14 =19,086,476nm (approximately 19mm), the second synthetic wavelength L 13 =762,646.31nm (about 762 microns), the third synthetic wavelength L 14 = 43,798 nm (approximately 44 microns) and the fourth composite wavelength (note: this was not defined previously) L λ =781.5nm. Since the wavelengths of the lasers mentioned above are very stable, the corresponding optical frequency differences between the lasers are also very stable. The stability required is inversely proportional to the distance to be measured. That is, the larger the distance to be measured, the higher the required frequency accuracy. The frequency difference between the wavelengths changes in the opposite direction to the distance to be measured. For example, for a measurement distance of 30 meters, it is approximately Δf / f<10 -7 , and for a measurement distance of 10 meters, Δf / f<3*10 -7 .

[0126] Optionally, the four wavelength-stable single-frequency lasers mentioned above are used as light sources, and all lasers are divided into two paths: one path is used as local light in coherent detection, and the other path is combined through a fiber coupler. The combined continuous wave laser is formed into a pulse with a pulse width of 20ns by an acousto-optic modulator (AOM). After being amplified by an erbium-doped fiber amplifier (EDFA), the multi-wavelength laser pulse is guided to the reflector of the target to be measured through a circulator and a fiber collimator. The laser pulse has a weak reflection on the surface of the collimator, and the reflecting surface serves as a reference for ranging. The pulse reflected by the target is collected by the collimator and returned to the beam splitter constructed by the fiber coupler, which divides the pulse returned from the reference surface and the target into four paths, which interfere with the four continuous wave local lights respectively. The interfered optical signal is detected by four balanced photodetectors (BPDs) and analyzed by the electrical signal processing system. Using the above-mentioned four-wavelength laser phase measurement system for coherent ranging, based on the laser wavelength parameters and frequency stability, ultra-high-precision distance measurement can be carried out at distances of around 30 meters and around 10 meters. Precision ranging with an accuracy of 5nm or higher can be achieved at a pulse repetition frequency of 100kHz.

[0127] In some embodiments, the flight ranging pulse and the first ranging pulse, the second ranging pulse, the third ranging pulse and the fourth ranging pulse belong to the same pulse, and the flight reflection pulse and the fourth ranging reflection pulse belong to the same pulse.

[0128] As a way to avoid measurement errors caused by the different times of sending pulses of different wavelengths, the same pulse can be modulated into a flight ranging pulse, a first ranging pulse, a second ranging pulse, a third ranging pulse and a fourth ranging pulse through a pulse modulator. In this way, the corresponding flight reflection pulse, the first ranging reflection pulse, the second ranging reflection pulse, the third ranging reflection pulse and the fourth ranging reflection pulse also belong to the same pulse.

[0129] Optionally, the light waves of the same light source can be modulated into a first local continuous wave, a second local continuous wave, a third local continuous wave and a fourth continuous wave, respectively, and then the first local continuous wave, the second local continuous wave, the third local continuous wave and the fourth continuous wave are pulse-modulated by the same pulse modulator to obtain a first ranging pulse, a second ranging pulse, a third ranging pulse and a fourth ranging pulse.

[0130] Optionally, in order to avoid measurement errors caused by the different times of sending pulses of different wavelengths, the flight ranging pulse can be spliced ​​with the first ranging pulse, the second ranging pulse, the third ranging pulse and the fourth ranging pulse and placed in the same pulse envelope, so that the flight ranging pulse and the first ranging pulse, the second ranging pulse, the third ranging pulse and the fourth ranging pulse can be sent simultaneously.

[0131] Optionally, the first reference pulse, the second reference pulse, the third reference pulse and the fourth reference pulse may also be placed in the same pulse envelope as the flight ranging pulse, the first ranging pulse, the second ranging pulse, the third ranging pulse and the fourth ranging pulse to ensure that they can be sent simultaneously.

[0132] In some embodiments, the phase corresponding to any interference information among the first ranging interference information, the first reference interference information, the second ranging interference information, the second reference interference information, the third ranging interference information, the third reference interference information, the fourth ranging interference information and the fourth reference interference information is determined by performing heterodyne detection on the interference fringes of the reflected pulse and the corresponding local continuous wave.

[0133] As a method, an acousto-optic modulator can be inserted into the reference optical path of the laser pulse in the target to be measured, thereby applying a heterodyne frequency to the reference reflected pulse and the local continuous wave, so that the interference signal I can be obtained from the reference reflected pulse and the local continuous wave. t =I1+I2+2I1I2 cos(2πf shiftt+Δφ), where I1 is the reference reflected pulse, I2 is the local continuous wave, Δφ is the phase difference between the reference reflected pulse and the local continuous wave, and f s h ift is the heterodyne frequency, and then the light intensity signal is converted into an electrical signal V by a photodetector (t) =V DC +V AC cos(2πf shift t+Δφ), where V DC is the DC component (proportional to I1+I2), V AC is the AC component increase (proportional to ), and thus the phase of the beat frequency signal is demodulated by I / Q quadrature demodulation θ=2πf shift t+Δφ, separate Δφ to obtain the phase corresponding to the interference fringes corresponding to the reference reflected pulse and the local continuous wave.

[0134] In some embodiments, the frequency difference between the first wavelength and the fourth wavelength is greater than the frequency difference between the first wavelength and the third wavelength, and the frequency difference between the first wavelength and the third wavelength is greater than the frequency difference between the first wavelength and the second wavelength.

[0135] As a way to ensure that the synthetic wavelength can be used to synthesize the fuzzy distance of a single wavelength in the method based on single-wavelength interferometry, it is necessary to ensure that there is a certain frequency difference between different pulses so that the synthetic wavelength can be obtained.

[0136] Optionally, in order to achieve step-by-step precision, the frequency difference between the first wavelength and the fourth wavelength can be set to be greater than the frequency difference between the first wavelength and the third wavelength, and the frequency difference between the first wavelength and the third wavelength can be set to be greater than the frequency difference between the first wavelength and the second wavelength. In this way, when the first coefficient, the second coefficient and the third coefficient are determined in sequence, the precision of the corresponding first ranging result, the second ranging result and the third ranging result becomes higher and higher.

[0137] In this embodiment, due to the demand for accuracy of the ranging result, when the accuracy requirement is high, comprehensive ranging can be performed by combining laser ranging pulses of more wavelengths. In this way, on the basis of the first ranging result that has been determined, a laser pulse and a local continuous wave of a third wavelength and a laser pulse and a local continuous wave of a fourth wavelength are introduced to obtain third interference information and fourth interference information. In order to refine the ranging result step by step, the second synthetic wavelength is first determined in sequence. In this way, based on the first ranging result, a second coefficient and a second residual distance representing the remaining distance beyond a multiple of half the second synthetic wavelength can be determined in sequence based on the second synthetic wavelength, the first wavelength, the third wavelength, the first interference information and the third interference information. In this way, based on the second synthetic wavelength, the second residual distance and the third interference information, a second coefficient and a second residual distance representing the remaining distance beyond a multiple of half the second synthetic wavelength can be determined in sequence. The second ranging result is determined by using two coefficients, and then the third coefficient, the third synthetic wavelength and the third residual distance are determined based on the second ranging result according to the same steps based on the laser pulse of the fourth wavelength and the local continuous wave, so that the third ranging result can be determined based on the third coefficient, the third synthetic wavelength and the third residual distance. Finally, in order to align the ranging result with the accuracy of the laser pulse, based on the same steps above, on the basis of the third ranging result, the fourth coefficient and the fourth residual distance representing the remaining distance beyond the multiple of half of the first wavelength are determined according to the first wavelength and the first interference information, so that the fourth coefficient, the fourth residual distance and the first wavelength can be used to determine the fourth ranging result with the highest final accuracy, so as to achieve the long-distance ranging while meeting the accuracy requirements.

[0138] Figure 6 FIG. 1 is a block diagram of a laser ranging device according to an embodiment of the present application. Figure 6 As shown, the laser ranging device 400 includes: a first sending module 410, a second sending module 420, a third sending module 430, a first interference information determination module 440, a second interference information determination module 450, an error time interval determination module 460, an initial ranging distance determination module 470, a first coefficient determination module 480 and a first ranging result determination module 490.

[0139] The first transmitting module 410 is configured to transmit a ranging pulse and receive a reflected ranging pulse reflected by a target to be measured, thereby obtaining an initial time interval between transmitting the ranging pulse and receiving the reflected ranging pulse. The second transmitting module 420 is configured to transmit a first ranging pulse of a first wavelength and a first reference pulse of a first wavelength, and receive a first ranging reflected pulse reflected by the target to be measured and a first reference reflected pulse reflected by the first reference pulse from a reference surface, wherein the ranging pulse and the first ranging pulse are the same pulse, or the ranging pulse and the first ranging pulse are two different pulses transmitted simultaneously. The third transmitting module 430 is configured to transmit a second ranging pulse of a second wavelength and a second reference pulse of a second wavelength, and receive a second ranging reflected pulse reflected by the target to be measured and a second reference reflected pulse reflected by the second reference pulse from the reference surface. The first interference information determining module 440 is configured to perform interference between the first ranging reflected pulse and a first local continuous wave to obtain first ranging interference information, and perform interference based on the first reference reflected pulse and the first local continuous wave to obtain first reference interference information, wherein , the first local continuous wave and the first ranging pulse belong to the same light source; a second interference information determination module 450 is configured to interfere the second ranging reflection pulse with the second local continuous wave to obtain second ranging interference information, and to interfere the second reference reflected pulse with the second local continuous wave to obtain second reference interference information, wherein the second local continuous wave and the second ranging pulse belong to the same light source; an error time interval determination module 460 is configured to determine the error time interval based on the first reference pulse and the first reference reflected pulse; an initial ranging distance determination module 470 is configured to determine the initial ranging distance based on the initial time interval and the error time interval; a first coefficient determination module 480 is configured to determine a first synthetic wavelength based on the first wavelength and the second wavelength, and to determine a first coefficient based on the initial ranging distance and the first synthetic wavelength, wherein the first coefficient represents a multiple of half of the first synthetic wavelength included in the distance to be measured corresponding to the target to be measured, and the first coefficient is an integer; a first ranging result determination module 490 is configured to determine a first ranging result for the distance to be measured based on the first coefficient, the first synthetic wavelength, the first ranging interference information, the first reference interference information, the second ranging interference information, and the second reference interference information.

[0140] In some embodiments, the first ranging result determination module 490 includes: a phase difference determination unit, used to determine the first phase difference based on the first ranging interference information and the first reference interference information, and to determine the second phase difference based on the second ranging interference information and the second reference interference information; a first residual distance determination unit, used to determine the first residual distance based on the first phase difference, the second phase difference and the first synthetic wavelength, wherein the first residual distance represents the remaining distance beyond the multiple of the first synthetic wavelength; and a first ranging result determination unit, used to determine the first ranging result based on the first coefficient, the first synthetic wavelength and the first residual distance.

[0141] In some embodiments, the laser ranging device 400 further includes: a fourth sending module, configured to send, while sending the first ranging pulse of the first wavelength, a third ranging pulse and a third reference pulse of the third wavelength, and a fourth ranging pulse and a fourth reference pulse of the fourth wavelength, respectively; and receive a third ranging reflection pulse reflected by the third ranging pulse from the target to be measured, and receive a fourth ranging reflection pulse reflected by the fourth ranging pulse from the target to be measured, and receive a third reference reflection pulse reflected by the third reference pulse from the reference surface, and receive a fourth reference reflection pulse reflected by the fourth reference pulse from the reference surface, wherein there is a frequency difference between the third wavelength and the first wavelength, and there is a frequency difference between the fourth wavelength and the first wavelength; a third interference information determination module, configured to The third ranging reflected pulse is interfered with the third local continuous wave to obtain third ranging interference information, and the third reference reflected pulse is interfered with the third local continuous wave to obtain third reference interference information, wherein the third local continuous wave and the third ranging pulse belong to the same light source; a fourth interference information determination module is used to interfere the fourth ranging reflected pulse with the fourth local continuous wave to obtain fourth ranging interference information, and interfere the fourth reference reflected pulse with the fourth local continuous wave to obtain fourth reference interference information, wherein the fourth local continuous wave and the fourth ranging pulse belong to the same light source; a second synthetic wavelength determination module is used to determine a second synthetic wavelength according to the first wavelength and the third wavelength, wherein the accuracy of the second synthetic wavelength is higher than that of the first synthetic wavelength. a synthetic wavelength; a second coefficient determination module, configured to determine a second coefficient based on the first ranging result and the second synthetic wavelength, wherein the second coefficient represents a multiple of half of the second synthetic wavelength contained in the distance to be measured, and the second coefficient is an integer; a second residual distance determination module, configured to determine a third phase difference based on third ranging interference information and third reference interference information, and determine a second residual distance corresponding to the distance to be measured based on the third phase difference, the first phase difference and the second synthetic wavelength, wherein the second residual distance represents the remaining distance beyond the multiple of half of the second synthetic wavelength; a second ranging result determination module, configured to determine a second ranging result based on the second coefficient, the second synthetic wavelength and the second residual distance, wherein the accuracy of the second ranging result higher than the first ranging result; a third synthetic wavelength determination module, configured to determine a third synthetic wavelength based on the first wavelength and the fourth wavelength, wherein the accuracy of the third synthetic wavelength is higher than that of the second synthetic wavelength; a third coefficient determination module, configured to determine a third coefficient based on the second ranging result and the third synthetic wavelength, wherein the third coefficient represents a multiple of half of the third synthetic wavelength contained in the distance to be measured, and the third coefficient is an integer; a third residual distance determination module, configured to determine a fourth phase difference based on the fourth ranging interference information and the fourth reference interference information, and determine a third residual distance corresponding to the distance to be measured based on the fourth phase difference, the first phase difference, and the third synthetic wavelength, wherein the third residual distance represents a distance other than the multiple of half of the third synthetic wavelength;A third ranging result determination module is configured to determine a third ranging result based on a third coefficient, a third synthetic wavelength, and a third residual distance, wherein the third ranging result has a higher precision than the second ranging result. A fourth coefficient determination module is configured to determine a fourth coefficient based on the first wavelength and the third ranging result, wherein the fourth coefficient represents a multiple of half the first wavelength included in the distance to be measured and is an integer. A fourth ranging result determination module is configured to determine a fourth residual distance based on the first wavelength and the first phase difference, and to determine a fourth ranging result based on the fourth coefficient, the first wavelength, and the fourth residual distance, wherein the fourth residual distance represents the remaining distance beyond the multiple of half the first wavelength, and the fourth ranging result has a higher precision than the third ranging result.

[0142] In some embodiments, the flight ranging pulse and the first ranging pulse, the second ranging pulse, the third ranging pulse and the fourth ranging pulse belong to the same pulse, and the flight reflection pulse and the first ranging reflection pulse, the second ranging reflection pulse, the third ranging reflection pulse and the fourth ranging reflection pulse belong to the same pulse.

[0143] In some embodiments, the phase corresponding to any interference information among the first ranging interference information, the first reference interference information, the second ranging interference information, the second reference interference information, the third ranging interference information, the third reference interference information, the fourth ranging interference information and the fourth reference interference information is determined by performing heterodyne detection on the interference fringes of the reflected pulse and the corresponding local continuous wave.

[0144] In some embodiments, the flight ranging pulse and the first ranging pulse belong to the same pulse.

[0145] In some embodiments, the frequency difference between the first wavelength and the fourth wavelength is smaller than the frequency difference between the first wavelength and the third wavelength, and the frequency difference between the first wavelength and the third wavelength is smaller than the frequency difference between the first wavelength and the second wavelength.

[0146] According to one aspect of the embodiments of the present application, an electronic device is also provided, such as Figure 7 As shown, the electronic device 500 includes a processor 510 and one or more memories 520. The one or more memories 520 are used to store program instructions executed by the processor 510. When the processor 510 executes the program instructions, the above-mentioned laser ranging method is implemented.

[0147] Furthermore, the processor 510 may include one or more processing cores. The processor 510 runs or executes instructions, programs, code sets or instruction sets stored in the memory 520, and calls data stored in the memory 520. Optionally, the processor 510 can be implemented in at least one hardware form of digital signal processing (DSP), field-programmable gate array (FPGA), and programmable logic array (PLA). The processor 510 can integrate one or a combination of a central processing unit (CPU), a graphics processing unit (GPU), and a modem. Among them, the CPU mainly processes the operating system, user interface, and application programs; the GPU is responsible for rendering and drawing display content; and the modem is used to handle wireless communications. It is understandable that the above-mentioned modem may not be integrated into the processor and may be implemented separately through a communication chip.

[0148] According to one aspect of the present application, a computer-readable storage medium is provided. The computer-readable storage medium may be included in the electronic device described in the above embodiments, or may exist independently without being incorporated into the electronic device. The computer-readable storage medium carries computer-readable instructions. When the computer-readable storage instructions are executed by a processor, the method of any of the above embodiments is implemented.

[0149] It should be noted that the computer-readable medium shown in the embodiments of the present application can be a computer-readable signal medium or a computer-readable storage medium or any combination of the above two. The computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples of computer-readable storage media can include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a flash memory, an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present application, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in combination with an instruction execution system, device or device. In the present application, a computer-readable signal medium can include a data signal propagated in baseband or as part of a carrier wave, which carries a computer-readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A computer-readable signal medium may also be any computer-readable medium other than a computer-readable storage medium that can transmit, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. Program code embodied on a computer-readable medium may be transmitted using any suitable medium, including but not limited to wireless, wired, or any suitable combination thereof.

[0150] The units involved in the embodiments described in this application may be implemented by software or hardware, and the units described may also be set in a processor. In some cases, the names of these units do not constitute limitations on the units themselves.

[0151] The above examples are used to illustrate the present invention, which are only used to help understand the present invention and are not intended to limit the present invention. Those skilled in the art can make several simple deductions, modifications or substitutions based on the concept of the present invention.

Claims

1. A laser ranging method, characterized in that: The method comprises: Sending a flight ranging pulse and receiving a flight reflected pulse reflected by the flight ranging pulse from the target to be measured, thereby obtaining an initial time interval from sending the transmitted flight ranging pulse to receiving the flight reflected pulse; sending a first ranging pulse of a first wavelength and a first reference pulse of the first wavelength, and receiving a first ranging reflected pulse reflected by the first ranging pulse from a target to be measured and a first reference reflected pulse reflected by the first reference pulse from a reference surface, wherein the flight ranging pulse and the first ranging pulse are the same pulse, or the flight ranging pulse and the first ranging pulse are two different pulses sent simultaneously; Sending a second ranging pulse of a second wavelength and a second reference pulse of a second wavelength, and receiving a second ranging reflected pulse reflected by the second ranging pulse from the target to be measured and a second reference reflected pulse reflected by the second reference pulse from the reference surface; interfering the first ranging reflected pulse with the first local continuous wave to obtain first ranging interference information, and interfering the first reference reflected pulse with the first local continuous wave to obtain first reference interference information, wherein the first local continuous wave and the first ranging pulse belong to the same light source; interfering the second ranging reflected pulse with the second local continuous wave to obtain second ranging interference information, and interfering the second reference reflected pulse with the second local continuous wave to obtain second reference interference information, wherein the second local continuous wave and the second ranging pulse belong to the same light source; determining an error time interval based on the first reference pulse and the first reference reflected pulse; determining an initial ranging distance according to the initial time interval and the error time interval; Determining a first composite wavelength based on the first wavelength and the second wavelength, and determining a first coefficient based on the initial ranging distance and the first composite wavelength, wherein the first coefficient represents a multiple of half of the first composite wavelength contained in the distance to be measured corresponding to the target to be measured, and the first coefficient is an integer; A first ranging result of the distance to be measured is determined according to the first coefficient, the first synthetic wavelength, the first ranging interference information, the first reference interference information, the second ranging interference information, and the second reference interference information.

2. The method according to claim 1, characterized in that The determining of the first ranging result of the distance to be measured according to the first coefficient and the first residual distance, the first synthetic wavelength, the first ranging interference information, the first reference interference information, the second ranging interference information, and the second reference interference information includes: determining a first phase difference according to the first ranging interference information and the first reference interference information, and determining a second phase difference according to the second ranging interference information and the second reference interference information; determining a first residual distance according to the first phase difference, the second phase difference, and the first synthetic wavelength, wherein the first residual distance represents a remaining distance beyond a multiple of the first synthetic wavelength; A first distance measurement result is determined according to the first coefficient, the first synthesized wavelength, and the first residual distance.

3. The method according to claim 1, characterized in that The method further comprises: While transmitting the first ranging pulse of the first wavelength, respectively transmitting a third ranging pulse and a third reference pulse of the third wavelength and a fourth ranging pulse and a fourth reference pulse of the fourth wavelength, and receiving a third ranging reflected pulse reflected by the third ranging pulse from the target to be measured, receiving a fourth ranging reflected pulse reflected by the fourth ranging pulse from the target to be measured, and receiving a third reference reflected pulse reflected by the third reference pulse from a reference surface, and receiving a fourth reference reflected pulse reflected by the fourth reference pulse from the reference surface, wherein there is a frequency difference between the third wavelength and the first wavelength, and there is a frequency difference between the fourth wavelength and the first wavelength; interfering the third ranging reflected pulse with the third local continuous wave to obtain third ranging interference information, and interfering the third reference reflected pulse with the third local continuous wave to obtain third reference interference information, wherein the third local continuous wave and the third ranging pulse belong to the same light source; interfering the fourth ranging reflected pulse with the fourth local continuous wave to obtain fourth ranging interference information, and interfering the fourth reference reflected pulse with the fourth local continuous wave to obtain fourth reference interference information, wherein the fourth local continuous wave and the fourth ranging pulse belong to the same light source; determining a second synthesized wavelength based on the first wavelength and the third wavelength, wherein the second synthesized wavelength has a higher precision than the first synthesized wavelength; Determine a second coefficient according to the first distance measurement result and the second synthetic wavelength, wherein the second coefficient represents a multiple of half of the second synthetic wavelength contained in the distance to be measured, and the second coefficient is an integer; determining a third phase difference according to the third ranging interference information and the third reference interference information, and determining a second residual distance corresponding to the distance to be measured according to the third phase difference, the first phase difference, and the second synthetic wavelength, wherein the second residual distance represents a remaining distance beyond a multiple of half the second synthetic wavelength; determining a second ranging result according to the second coefficient, the second synthetic wavelength, and the second residual distance, wherein the second ranging result has a higher precision than the first ranging result; determining a third composite wavelength based on the first wavelength and the fourth wavelength, wherein the third composite wavelength has a higher precision than the second composite wavelength; determining a third coefficient according to the second distance measurement result and the third synthetic wavelength, wherein the third coefficient represents a multiple of half of the third synthetic wavelength contained in the distance to be measured, and the third coefficient is an integer; determining a fourth phase difference according to the fourth ranging interference information and the fourth reference interference information, and determining a third residual distance corresponding to the distance to be measured according to the fourth phase difference, the first phase difference, and the third synthetic wavelength, wherein the third residual distance represents a distance other than a multiple of half the third synthetic wavelength; determining a third ranging result according to the third coefficient, the third synthetic wavelength, and the third residual distance, wherein the third ranging result has a higher precision than the second ranging result; determining a fourth coefficient according to the first wavelength and the third distance measurement result, wherein the fourth coefficient represents a multiple of half of the first wavelength contained in the distance to be measured, and the fourth coefficient is an integer; A fourth residual distance is determined based on the first wavelength and the first phase difference, and a fourth ranging result is determined based on the fourth coefficient, the first wavelength, and the fourth residual distance, wherein the fourth residual distance represents a remaining distance beyond a multiple of half the first wavelength, and the accuracy of the fourth ranging result is higher than that of the third ranging result.

4. The method according to claim 3, characterized in that The flight ranging pulse and the first ranging pulse, the second ranging pulse, the third ranging pulse and the fourth ranging pulse belong to the same pulse, and the flight reflection pulse and the first ranging reflection pulse, the second ranging reflection pulse, the third ranging reflection pulse and the fourth ranging reflection pulse belong to the same pulse.

5. The method according to any one of claims 1 to 4, characterized in that The phase corresponding to any interference information among the first ranging interference information, the first reference interference information, the second ranging interference information, the second reference interference information, the third ranging interference information, the third reference interference information, the fourth ranging interference information and the fourth reference interference information is determined by performing heterodyne detection on the interference fringes of the reflected pulse and the corresponding local continuous wave.

6. The method according to claim 5, characterized in that The flight ranging pulse and the first ranging pulse belong to the same pulse.

7. The method according to claim 5, characterized in that The frequency difference between the first wavelength and the fourth wavelength is greater than the frequency difference between the first wavelength and the third wavelength, and the frequency difference between the first wavelength and the third wavelength is greater than the frequency difference between the first wavelength and the second wavelength.

8. A laser ranging device, characterized in that: The device comprises: A first transmitting device is configured to transmit a flight ranging pulse and receive a flight reflected pulse that is reflected by a target to be measured, thereby obtaining an initial time interval between transmitting the transmitted flight ranging pulse and receiving the flight reflected pulse; a second transmitting device, configured to transmit a first ranging pulse of a first wavelength and a first reference pulse of the first wavelength, and receive a first ranging reflected pulse reflected by the first ranging pulse from the target to be measured and a first reference reflected pulse reflected by the first reference pulse from a reference surface, wherein the flight ranging pulse and the first ranging pulse are the same pulse, or the flight ranging pulse and the first ranging pulse are two different pulses transmitted simultaneously; a third transmitting device, configured to transmit a second ranging pulse of a second wavelength and a second reference pulse of a second wavelength, and receive a second ranging reflected pulse reflected by the second ranging pulse from the target to be measured and a second reference reflected pulse reflected by the second reference pulse from the reference surface; a first interference information determination module, configured to perform interference on the first ranging reflected pulse and the first local continuous wave to obtain first ranging interference information, and to perform interference on the first reference reflected pulse and the first local continuous wave to obtain first reference interference information, wherein the first local continuous wave and the first ranging pulse belong to the same light source; a second interference information determination module, configured to interfere the second ranging reflected pulse with the second local continuous wave to obtain second ranging interference information, and interfere the second reference reflected pulse with the second local continuous wave to obtain second reference interference information, wherein the second local continuous wave and the second ranging pulse belong to the same light source; an error time interval determining module, configured to determine an error time interval based on a first reference pulse and a first reference reflected pulse; an initial ranging distance determination module, configured to determine an initial ranging distance according to the initial time interval and the error time interval; a first coefficient determination module, configured to determine a first composite wavelength based on the first wavelength and the second wavelength, and determine a first coefficient based on the initial ranging distance and the first composite wavelength, wherein the first coefficient represents a multiple of half of the first composite wavelength contained in the distance to be measured corresponding to the target to be measured, and the first coefficient is an integer; The first ranging result determination module is configured to determine a first ranging result of the distance to be measured according to the first coefficient, the first synthetic wavelength, the first ranging interference information, the first reference interference information, the second ranging interference information, and the second reference interference information.

9. An electronic device, characterized in that: The electronic device comprises: processor; A memory having computer-readable instructions stored thereon, wherein when the computer-readable instructions are executed by the processor, the method according to any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores program code, which can be called by a processor to execute the method according to any one of claims 1 to 7.

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