Phase ranging method and system

Abstract

The invention relates to the technical field of laser measurement, in particular to a phase distance measurement method and system. The method comprises the steps that modulated signal light containing high-frequency modulation signals of at least three different frequencies is transmitted to a target to be subjected to distance measurement, the phase difference of echoes of the target is determined, and high-frequency bands and low-frequency bands of the modulation signals are divided according to a preset standard; simulating an equivalent modulation signal based on the high-frequency modulation signals of three different frequencies carried by the modulated signal light, the equivalent frequency of the equivalent modulation signal being a difference value between the sum of the frequencies of the first modulation signal and the second modulation signal and twice the frequency of the third modulation signal, the equivalent phase difference is two times of the sum of the phase differences of the first modulation signal and the second modulation signal and the phase difference of the third modulation signal; based on the equivalent frequency of the equivalent modulation signal and the corresponding equivalent phase difference, determining the distance to the to-be-ranged target; according to the invention, the distance of a long-distance moving object can be accurately measured.

Description

Technical Field

[0001] The present invention relates to the field of laser measurement technology, and in particular to a phase ranging method and system. Background Art

[0002] Laser phase rangefinders are widely used in the field of precise distance measurement. The principle of phase ranging is to calculate time and distance by measuring the phase change of the modulated signal carried by the modulated light during the round trip.

[0003] The high-frequency signal carried during phase ranging has high ranging accuracy, but a short effective range; the low-frequency signal carried has a long effective range, but poor accuracy. Therefore, for accurate ranging of long-distance targets, a dual-frequency laser phase rangefinder is required to estimate the distance with a low-frequency modulated signal, and then use a high-frequency modulated signal to correct the estimated distance to obtain the precise distance.

[0004] The phase change is obtained by comparing the phase difference of the modulated signal carried in the modulated light obtained at different times during the round trip. However, in this time interval, the moving object will be displaced, resulting in motion error. The dual-frequency laser phase rangefinder maintains this motion error, so it cannot accurately measure the distance of moving objects at long distances. Summary of the invention

[0005] In view of this, an object of the embodiments of the present invention is to provide a phase ranging method and system to accurately measure the distance of a moving object at a long distance.

[0006] In a first aspect, the present invention provides a phase ranging method, comprising:

[0007] Transmitting modulated signal light containing at least three high-frequency modulated signals of different frequencies to the target to be measured and determining the phase difference of its echo, wherein the high-frequency band and the low-frequency band of the modulated signal are divided according to a preset standard;

[0008] Simulating an equivalent modulation signal based on the high-frequency modulation signals of three different frequencies carried by the modulated signal light, wherein the equivalent frequency of the equivalent modulation signal is the difference between the sum of the frequencies of the first modulation signal and the second modulation signal and twice the frequency of the third modulation signal, and the equivalent phase difference is the difference between the sum of the phase differences of the first modulation signal and the second modulation signal and twice the phase difference of the third modulation signal;

[0009] The distance to the target to be measured is determined based on the equivalent frequency of the equivalent modulation signal and the corresponding equivalent phase difference.

[0010] Optionally, the equivalent phase difference is a difference between the sum of the phase differences between the first modulation signal and the second modulation signal and twice the phase difference of the third modulation signal, including:

[0011]

[0012] in, is the equivalent phase difference of the equivalent modulation signal, are respectively one of the phase differences of the high-frequency modulation signal, and k is an integer.

[0013] Optionally, the transmitting of modulated signal light containing high-frequency modulation signals of at least three different frequencies to the target to be measured and determining the phase difference of its echo includes:

[0014] Modulate three high-frequency signals of different frequencies on the carrier in turn according to a preset order to generate modulated signal light;

[0015] The modulated signal light is emitted, and the phase difference between the three most recently received consecutive echoes is determined.

[0016] Optionally, after determining the distance to the target to be measured, the step further includes:

[0017] The phase difference of any modulated signal in the modulated signal light is continuously determined, and the distance to the target to be measured is continuously determined based on the phase difference.

[0018] Optionally, determining the distance to the target to be measured based on the equivalent frequency and the corresponding equivalent phase difference includes:

[0019] Simulating three equivalent modulation signals based on the modulated signal light, wherein the first equivalent modulation signal with the lowest frequency is in a low frequency band;

[0020] Determine a first estimated distance to the target to be measured based on the first equivalent modulation signal;

[0021] Correcting the first estimated distance based on the remaining two second equivalent modulation signals to determine a second estimated distance to the target to be measured;

[0022] The second estimated distance is corrected based on the high-frequency modulation signal to determine the precise distance to the target to be measured.

[0023] Optionally, determining a first estimated distance to the target to be measured based on the first equivalent modulation signal includes:

[0024]

[0025] Wherein, L1 is the first estimated distance to the target to be measured, C is the speed of light in the ranging environment, γ′ is the equivalent frequency of the first equivalent modulation signal, is the equivalent phase difference.

[0026] Optionally, correcting the first estimated distance based on the second equivalent modulation signal includes:

[0027] Determining the number of cycles of the second equivalent modulation signal transmitting the first estimated distance;

[0028] The first estimated distance is corrected based on the number of cycles, wherein:

[0029]

[0030] Wherein, L2 is the second estimated distance to the target to be measured, C is the speed of light in the ranging environment, γ′ is the equivalent frequency of the second equivalent modulation signal, is the equivalent phase difference corresponding to γ′, N is the number of cycles, and λ is the equivalent wavelength of the second equivalent modulation signal.

[0031] Optionally, determining the number of cycles for the second equivalent modulation signal to transmit the first estimated distance further includes:

[0032] Determine the equivalent wavelengths of the two second equivalent modulation signals respectively, and use half of the equivalent wavelength with a shorter wavelength as a comparison distance;

[0033] If the difference between the two second estimated distances respectively determined based on each of the second equivalent modulation signals is greater than the comparison distance, the number of cycles is adjusted based on a preset rule until the difference is no greater than the comparison distance.

[0034] Optionally, after determining the precise distance to the target to be measured, the method further includes:

[0035] If the three precise distances obtained based on the three high-frequency modulated signals carried by the modulated signal light satisfy:

[0036] If the difference between the precise distances is greater than a preset threshold, the current measurement is invalid.

[0037] In a second aspect, the present invention provides a phase ranging system, comprising:

[0038] A transmitting module, used for transmitting modulated signal light containing high-frequency modulated signals of at least three different frequencies to a target to be measured and determining a phase difference of its echo, wherein the high-frequency band and the low-frequency band of the modulated signal are divided according to a preset standard;

[0039] A simulation module, used for simulating an equivalent modulation signal based on the high-frequency modulation signals of three different frequencies carried by the modulated signal light, wherein the equivalent frequency of the equivalent modulation signal is the difference between the sum of the frequencies of the first modulation signal and the second modulation signal and twice the frequency of the third modulation signal, and the equivalent phase difference is the difference between the sum of the phase difference of the first modulation signal and the second modulation signal and twice the phase difference of the third modulation signal;

[0040] A determination module is used to determine the distance to the target to be measured based on the equivalent frequency and the corresponding equivalent phase difference of the equivalent modulation signal.

[0041] The embodiments of the present invention include the following beneficial effects: This embodiment estimates the distance to a long-distance moving target based on the first equivalent modulation signal, and makes a first correction to the estimated distance based on the second equivalent modulation signal, and makes a second correction to the estimated distance based on the high-frequency modulation signal by using a modulated signal light containing three high-frequency modulation signals to be equivalent to a first low-frequency equivalent modulation signal and two second equivalent modulation signals with slightly higher frequencies, thereby obtaining an accurate distance to the long-distance moving target. Because when measuring the distance of a moving object through a modulated signal light containing three modulation signals, the motion errors introduced by the moving object during the measurement gap will cancel each other out, thereby achieving accurate distance measurement of a long-distance moving object; further, this embodiment gradually approaches the accurate distance to the target object through equivalent modulation signals of different frequencies, and can more accurately determine the number of cycles of high-frequency modulation signal propagation, thereby improving the efficiency of correcting the estimated distance and obtaining the accurate distance. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0043] Figure 1 It is a propagation diagram of modulated signal light including a modulated signal and its echo;

[0044] Figure 2 A flow chart of a phase ranging method provided by an embodiment of the present invention;

[0045] Figure 3 A schematic diagram of a phase ranging system provided by an embodiment of the present invention;

[0046] Figure 4 It is a schematic diagram of the structure of a multi-frequency laser device in one embodiment of the present invention. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0048] It should be noted that, although the functional modules are divided in the device schematic diagram and the logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the module division in the device or the order in the flowchart. The terms "first", "second", etc. in the specification, claims and the above drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0050] In addition, described feature, structure or characteristic can be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present application. However, those skilled in the art will appreciate that the technical scheme of the present application can be put into practice without one or more of the specific details, or other methods, components, devices, steps, etc. can be adopted. In other cases, known methods, devices, realizations or operations are not shown or described in detail to avoid blurring the various aspects of the application.

[0051] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities may be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0052] The flowcharts shown in the accompanying drawings are only exemplary and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps can be decomposed, and some operations / steps can be combined or partially combined, so the actual execution order may change according to actual conditions.

[0053] Laser phase rangefinders are widely used in the field of precise distance measurement. The principle of phase ranging is to calculate the time and distance by measuring the phase change of modulated light during the round trip.

[0054] Figure 1 It is a propagation diagram of the modulated signal light and its echo containing the modulated signal. Figure 1 As shown in the figure, the modulated signal light flies from the starting point to the end point and then returns to the starting point, propagating a distance twice the distance. During this period, the modulated signal has N complete cycles and 1 incomplete cycle, so there is

[0055] 2L=(N+ΔN)λ (1);

[0056] Among them, L is the distance from the starting point to the end point, N is the number of complete cycles, and ΔN is the phase tail number. The ratio of λ to 2π represents the wavelength of the modulated signal.

[0057] Simplifying, we get:

[0058]

[0059] This is the principle of single-frequency laser direct distance measurement. Where λ / 2 is the measuring length L s , which is the range. Since the number of whole cycles N is uncountable, and the phase tail number Can be measured (by comparing the departure and return states of the same signal).

[0060] So if and only if N = 0, From the definition of ΔN, we know that: At the same time, because so:

[0061] This is the phase ranging distance calculation formula for short distance (N=0), where: is the phase difference of the modulation signal, v is the frequency of the modulation signal, λ is the wavelength of the modulation signal, and c is the speed of light.

[0062] At this time, the range is λ / 2, and the accuracy is generally 1 / 1000 of the range, that is, λ / 2000. From this, we can see that the larger the range, the worse the measurement accuracy, and vice versa.

[0063] Therefore, laser phase ranging generally uses high-frequency modulation signals to obtain higher ranging accuracy.

[0064] The high-frequency modulated signal has high ranging accuracy, but a short effective range, while the low-frequency modulated signal has a long effective range and poor accuracy. Therefore, in order to accurately measure the distance of long-distance targets, a dual-band indirect ranging method is generally used, that is, using a low-frequency modulated signal to measure the distance and a high-frequency modulated signal to measure the accuracy. However, the hardware processing requirements for high-frequency signals and low-frequency signals are very different. If the laser phase rangefinder deploys both high-frequency and low-frequency processing systems, the hardware cost will increase significantly.

[0065] The above problems can be solved by using dual-frequency laser indirect ranging, that is, using two high-frequency modulation signals to be equivalent to one low-frequency modulation signal.

[0066] After changing formula (2), we have:

[0067]

[0068] Two wavelengths are introduced to represent the same distance, namely:

[0069]

[0070] According to the sum-division ratio theorem, we have:

[0071]

[0072] make:

[0073]

[0074] N′=N1-N2 (8);

[0075] ΔN′=ΔN1-ΔN2 (9);

[0076] Then formula (6) can be rewritten as:

[0077] L=L′ s (N′+ΔN′) (10);

[0078] Formula (10) is the principle of dual-frequency laser indirect ranging. Comparing formula (10) with formula (2), it can be seen that the range at this time is L′ s , the accuracy is L′ s / 1000. And L′ s It is strongly correlated with (λ2-λ1). When (λ2-λ1) is small, the range is large; when (λ2-λ1) is large, the accuracy is high.

[0079] Similarly, since the number of integer cycles N' is uncountable, but the phase tail can be measured, the indirect ranging formula is valid when and only when N' = 0. And when λ1≠λ2, N1=N2, and N′=0.

[0080] Dual-frequency laser indirect ranging uses two high-frequency modulation signals to be equivalent to one low-frequency modulation signal. The low-frequency modulation signal is used to estimate the distance of long-distance targets, and then the high-frequency modulation signal is used to obtain the precise distance, thereby achieving accurate ranging over long distances.

[0081] The frequencies are γ1 and γ2, and the phase differences are The equivalent frequency γ′ and equivalent phase difference of the equivalent modulation signal of the dual-frequency laser simulation They are:

[0082] γ′=|γ1-γ2|;

[0083]

[0084] In addition, laser phase ranging also faces the problem of motion error when measuring moving objects: from equation (3), the distance L depends on the phase difference If the phase of the modulated signal is measured at time t0 The phase of the modulated signal is measured at time t1 The phase difference The distance L is obtained from formula (3), but because the target to be measured is moving, the target to be measured moves ΔL within the phase difference measurement time interval Δt (Δt = (t1-t0)). This is the motion error introduced by the moving object.

[0085] Dual-frequency laser indirect ranging retains motion errors and cannot be used to accurately measure the distance of moving objects, as follows:

[0086] From equation (3), the motion error ΔL can be equivalently considered to introduce a corresponding equivalent phase difference error ΔS in the phase difference. When two frequency modulation signals are transmitted at a fixed time interval and echoes are received and processed at a fixed time interval to obtain the phase difference, if the modulation signal of γ1 is received at time t1, its phase difference is The modulated signal of γ2 is received at time t2, and its phase difference is

[0087] The equivalent phase difference of the dual-frequency laser is the phase difference between the first modulation signal and the second modulation signal, so the equivalent phase difference of the dual-frequency laser with motion error is:

[0088]

[0089] It can be seen that the equivalent phase difference between the dual-frequency laser without motion error is In contrast, the error ΔS of the equivalent phase difference introduced by the motion error still exists, which makes the result of dual-frequency laser indirect ranging inaccurate for moving targets.

[0090] In order to solve the problem of accurate distance measurement for long-distance moving objects, the present invention creatively introduces a three-frequency laser indirect distance measurement solution.

[0091] Take any 0<λ1<λ2<λ3, substitute into equation (10), and get:

[0092]

[0093] From equations (7), (8) and (9), we can get:

[0094]

[0095] The solution is:

[0096]

[0097] According to the definition of ΔN, we have:

[0098]

[0099] From the basic expression of the speed of light c = λν we know:

[0100] Substituting equations (14) and (15) into equation (12), we get:

[0101] From formula (1), we know:

[0102]

[0103] Based on the assumed conditions, we can get N1>N2>N3.

[0104] when When N1+N3-2N2=0, equation (15) can be transformed into

[0105] In the above formula, L represents the detection distance, c is the speed of light, Indicates the phase tail of the first modulated signal light, Indicates the phase tail of the second modulated signal light, represents the phase tail number of the third modulated signal light, ν1 represents the modulation frequency of the first modulated signal light, v2 represents the modulation frequency of the second modulated signal light, and v3 represents the modulation frequency of the third modulated signal light.

[0106] Formula (18) using conditions:

[0107] ① Order but like If it exceeds the range,

[0108]

[0109] ② The distance is a non-negative number, so v1+v3-2v2 needs to take an absolute value, and v1, v2, v3 are not an arithmetic progression;

[0110] ② Where c0 is the speed of light in a vacuum and n is the refractive index of air.

[0111] From the above, the equivalent frequency of the triple-frequency laser is the difference between the sum of the frequencies of the first laser and the second laser and twice the frequency of the third laser. The equivalent phase difference is the difference between the sum of the phase differences of the first laser echo and the second laser echo and twice the phase difference of the third laser echo. The frequencies are γ1, γ2, and γ3, respectively, and the phase differences are The equivalent frequency and equivalent phase difference of the equivalent modulation signal of the laser simulation are:

[0112] γ′=|γ1+γ3-2γ2|;

[0113]

[0114] When the modulated signals of the three frequencies are transmitted at fixed time intervals and the echoes are received and processed at fixed time intervals to obtain the phase difference, considering the motion error, if the modulated signal of γ1 is received at time t1, its phase difference is The modulated signal of γ2 is received at time t2, and its phase difference is T3 receives the laser of γ3, and its phase difference is Then the equivalent phase difference of the equivalent modulated signal is:

[0115] (when hour)

[0116] It can be seen that the errors of the equivalent phase difference introduced by the motion error are offset by each other in the three-frequency laser ranging. In other words, the three-frequency laser indirect ranging can accurately measure the distance of moving objects. At the same time, because it can also be equivalent to a low-frequency modulation signal, it can achieve the effect of dual-frequency laser indirect ranging and accurately measure the distance of long-distance targets. Combining the two, the three-frequency laser indirect ranging solves the problem of accurately measuring the distance of long-distance moving targets.

[0117] Figure 2 A flow chart of a phase ranging method provided in an embodiment of the present invention, the method comprising the following steps:

[0118] S210, transmitting modulated signal light containing high-frequency modulation signals of at least three different frequencies to a target to be measured and determining a phase difference of its echo, wherein the high-frequency band and the low-frequency band of the modulation signal are divided according to a preset standard.

[0119] Some embodiments of the present invention modulate three high-frequency signals of different frequencies on a carrier in turn in a preset order to generate modulated signal light, and determine the phase difference of the three most recently received consecutive echoes.

[0120] In one embodiment of the present invention, the modulation signals of three frequencies are ①100M②96M③92.4M, and the transmission order is ①②③①②③①②③……, and each distance measurement only needs to take the latest three consecutive echoes to calculate the phase difference. That is to say, the frequencies used to calculate the distance can only be the following three situations: ①②③, ②③①, ③①②;

[0121] S220, simulating an equivalent modulation signal based on the high-frequency modulation signal of three different frequencies carried by the modulated signal light, wherein the equivalent frequency of the equivalent modulation signal is the difference between the sum of the frequencies of the first modulation signal and the second modulation signal and twice the frequency of the third modulation signal, and the equivalent phase difference is the difference between the sum of the phase difference of the first modulation signal and the second modulation signal and twice the phase difference of the third modulation signal.

[0122] According to formula (18), If the order γ′=|γ1+γ3-2γ2|; then we can get The formula is similar to that of single-frequency laser direct distance measurement. The same; it can be considered that the frequencies are γ1, γ2, and γ3, and the phase differences are The modulated signal light containing the triple-frequency modulation signal simulates an equivalent modulation signal. The equivalent frequency of the equivalent modulation signal is: γ′=|γ1+γ3-2γ2|, and the equivalent phase difference is:

[0123]

[0124] In the above example, the high-frequency modulation signals of ①100M②96M③92.4M can simulate three equivalent modulation signals of 0.4M, 11.6M and 11.2M (obtained by substituting ①, ② and ③ as γ1 into the calculation formula of the equivalent frequency).

[0125] S230: Determine the distance to the target to be measured based on the equivalent frequency and the corresponding equivalent phase difference of the equivalent modulation signal.

[0126] Specifically, because the range of low-frequency modulation signals is large (for example, the equivalent modulation signal of 0.4M can measure more than 370 meters at most), for common distances, the number of whole cycles of low-frequency modulation signal propagation N=0, which can be directly used At the same time, because the accuracy of low-frequency modulation signals is low, the distance obtained can only be an estimate of the distance to the target to be measured.

[0127] Therefore, it is necessary to use a more accurate high-frequency modulation signal to correct the estimated distance. When correcting, first determine the number of cycles of the high-frequency modulation signal propagation based on the estimated distance. Accurate distance measurement.

[0128] Because the accuracy of low-frequency modulation signals is very low, the noise jitter may be greater than the period of a high-frequency modulation signal. Therefore, the determination of the number of cycles N requires experience. The present invention introduces a "step-by-step approximation" strategy to correct the estimated distance once through an equivalent modulation signal with a slightly higher frequency, and then correct it again based on the high-frequency laser, so as to more efficiently determine the precise distance.

[0129] In the above example, the high-frequency modulation signals of ①100M②96M③92.4M can simulate three equivalent modulation signals of 0.4M, 11.6M and 11.2M. The effective range of the 0.4M equivalent modulation signal is 370 meters, and the effective range of the 11.2M equivalent modulation signal is 12.9 meters; the effective range of the 11.6M equivalent modulation signal is 13.3 meters. Therefore, the 0.4M equivalent modulation signal is used to estimate the distance (obtaining 102 meters), and then the 11.2M equivalent modulation signal and the 11.2M equivalent modulation signal are used for correction.

[0130] In the first correction, the number of cycles required for the 11.6M equivalent modulation signal to transmit the estimated distance of 102 meters is 7.9 cycles. The first correction distance can be obtained by formula (20). Another first correction distance can be obtained by the 11.2M equivalent modulation signal. If the two first correction distances are very close, it means that the number of cycles is determined correctly and the distance measurement is correct. If the difference between the two first correction distances is greater than half the wavelength of the equivalent modulation signal with a shorter wavelength, the number of cycles needs to be adjusted until the difference is less than half the wavelength of the equivalent modulation signal with a shorter wavelength.

[0131] Then, based on the three high-frequency modulation signals, the corrected distance is corrected to obtain the accurate distance. The method is similar to correcting the estimated distance with two equivalent modulation signals.

[0132] In some embodiments of the present invention, the precise distance calculated based on the frequency of the most recently received modulation signal is directly output as the precise distance. In other embodiments of the present invention, the precise distances calculated based on the frequencies of the most recently received three modulation signals are averaged and the average is used as the precise distance.

[0133] Each step of the above distance measurement method has certain applicable conditions, such as when estimating the distance, the distance cannot exceed the range of the low-frequency equivalent modulation signal, and when correcting the distance, the calculation of the number of cycles must be accurate. If the applicable conditions are not met, the distance measurement result will have a large error. In order to determine whether this measurement is valid, the present invention verifies the results obtained by accurately measuring the distance using three high-frequency modulation signals. The verification conditions are:

[0134] If the difference between the precise distances is greater than a preset threshold, the current measurement is invalid.

[0135] Some embodiments of the present invention further include continuously determining the phase difference of the laser echo of any one frequency among the three high-frequency lasers, and continuously determining the distance to the target to be measured based on the phase difference, thereby achieving continuous distance measurement of the moving target.

[0136] Some embodiments of the present invention provide a phase ranging system. Figure 3 As shown, the phase ranging system includes a transmitting module 310, a simulation module 320 and a determination module 330, wherein:

[0137] The transmitting module 310 is used to transmit modulated signal light containing high-frequency modulated signals of at least three different frequencies to the target to be measured and determine the phase difference of its echo, wherein the high-frequency band and the low-frequency band of the modulated signal are divided according to a preset standard;

[0138] The simulation module 320 is used to simulate an equivalent modulation signal based on the high-frequency modulation signals of three different frequencies carried by the modulated signal light, wherein the equivalent frequency of the equivalent modulation signal is the difference between the sum of the frequencies of the first modulation signal and the second modulation signal and twice the frequency of the third modulation signal, and the equivalent phase difference is the difference between the sum of the phase difference of the first modulation signal and the second modulation signal and twice the phase difference of the third modulation signal;

[0139] The determination module 330 is used to determine the distance to the target to be measured based on the equivalent frequency and the corresponding equivalent phase difference of the equivalent modulation signal.

[0140] One embodiment of the present invention provides a multi-frequency laser phase ranging device. Figure 4 As shown, the multi-frequency laser phase ranging device includes a memory 420 and a processor 410, wherein the memory 420 is used to store a computer program; and the processor 410 is used to implement when executing the computer program. Figure 2 The method described in S210-S230.

[0141] The embodiment of the present invention includes the following beneficial effects: This embodiment estimates the distance to a long-distance moving target based on the first equivalent modulation signal, which is equivalent to a low-frequency first equivalent modulation signal and two second equivalent modulation signals with slightly higher frequencies based on three high-frequency lasers, performs a first correction on the estimated distance based on the second equivalent modulation signal, and performs a second correction on the estimated distance based on the high-frequency laser, thereby obtaining an accurate distance to the long-distance moving target. Because when measuring the distance of a moving object by using three-frequency lasers, the motion errors introduced by the moving object during the measurement gap will cancel each other out, thereby achieving accurate distance measurement of a long-distance moving object; further, this embodiment gradually approaches the target object through equivalent modulation signals of different frequencies, because the number of cycles of high-frequency laser propagation can be determined more accurately, which improves the efficiency of correcting the estimated distance and obtaining the accurate distance.

[0142] The device embodiments described above are merely illustrative, and the units described as separate components may or may not be physically separated, that is, they may be located in one place or distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0143] Those skilled in the art will appreciate that all or some of the steps in the methods disclosed above, and the functional modules / units in the systems and devices may be implemented as software, firmware, hardware, or a suitable combination thereof.

[0144] It should be understood that in the present application, the terms "include" and "have" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units need not be limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices. "At least one (item)" refers to one or more, and "plurality" refers to two or more. "And / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist, for example, "A and / or B" can represent: only A exists, only B exists, and A and B exist at the same time, wherein A, B can be singular or plural. The character " / " generally indicates that the associated objects before and after are in a "or" relationship. "At least one of the following (individuals)" or similar expressions thereof refer to any combination of these items, including any combination of singular (individuals) or plural (individuals). For example, at least one item among a, b or c can be represented by: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or plural.

[0145] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0146] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including multiple instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (Read-Only Memory, referred to as ROM), random access memory (Random Access Memory, referred to as RAM), disk or optical disk and other media that can store programs.

[0147] The preferred embodiments of the present invention are described above with reference to the accompanying drawings, but the scope of the rights of the present invention is not limited thereto. Any modification, equivalent substitution and improvement made by a person skilled in the art without departing from the scope and essence of the present invention should be within the scope of the rights of the present invention.

Claims

1. A phase ranging method, characterized in that: include: Transmitting modulated signal light containing at least three high-frequency modulated signals of different frequencies to the target to be measured and determining the phase difference of its echo, wherein the high-frequency band and the low-frequency band of the modulated signal are divided according to a preset standard; Simulating an equivalent modulation signal based on the high-frequency modulation signals of three different frequencies carried by the modulated signal light, wherein the equivalent frequency of the equivalent modulation signal is the difference between the sum of the frequencies of the first modulation signal and the second modulation signal and twice the frequency of the third modulation signal, and the equivalent phase difference is the difference between the sum of the phase differences of the first modulation signal and the second modulation signal and twice the phase difference of the third modulation signal; The distance to the target to be measured is determined based on the equivalent frequency of the equivalent modulation signal and the corresponding equivalent phase difference.

2. The method according to claim 1, characterized in that: The equivalent phase difference is the difference between the sum of the phase differences of the first modulation signal and the second modulation signal and twice the phase difference of the third modulation signal, including: in, is the equivalent phase difference of the equivalent modulation signal, are respectively one of the phase differences of the high-frequency modulation signal, and k is an integer.

3. The method according to claim 2, characterized in that: The step of transmitting modulated signal light containing high-frequency modulation signals of at least three different frequencies to the target to be measured and determining the phase difference of its echo comprises: Modulate three high-frequency signals of different frequencies on the carrier in turn according to a preset order to generate modulated signal light; The modulated signal light is emitted, and the phase difference between the three most recently received consecutive echoes is determined.

4. The method according to claim 3, characterized in that: After determining the distance to the target to be measured, the method further includes: The phase difference of any modulated signal in the modulated signal light is continuously determined, and the distance to the target to be measured is continuously determined based on the phase difference.

5. The method according to claim 4, characterized in that: The determining of the distance to the target to be measured based on the equivalent frequency and the corresponding equivalent phase difference comprises: Simulating three equivalent modulation signals based on the modulated signal light, wherein the first equivalent modulation signal with the lowest frequency is in a low frequency band; Determine a first estimated distance to the target to be measured based on the first equivalent modulation signal; Correcting the first estimated distance based on the remaining two second equivalent modulation signals to determine a second estimated distance to the target to be measured; The second estimated distance is corrected based on the high-frequency modulation signal to determine the precise distance to the target to be measured.

6. The method according to claim 5, characterized in that: Determining a first estimated distance to the target to be measured based on the first equivalent modulation signal includes: Wherein, L1 is the first estimated distance to the target to be measured, C is the speed of light in the ranging environment, and γ ’ is the equivalent frequency of the first equivalent modulation signal, is the equivalent phase difference.

7. The method according to claim 6, characterized in that: Correcting the first estimated distance based on the second equivalent modulation signal includes: Determining the number of cycles of the second equivalent modulation signal transmitting the first estimated distance; The first estimated distance is corrected based on the number of cycles, wherein: Wherein, L2 is the second estimated distance to the target to be measured, C is the speed of light in the ranging environment, γ′ is the equivalent frequency of the second equivalent modulation signal, is the equivalent phase difference corresponding to γ′, N is the number of cycles, and λ is the equivalent wavelength of the second equivalent modulation signal.

8. The method according to claim 7, characterized in that Determining the number of cycles during which the second equivalent modulation signal transmits the first estimated distance also includes: Determine the equivalent wavelengths of the two second equivalent modulation signals respectively, and use half of the equivalent wavelength with a shorter wavelength as a comparison distance; If the difference between the two second estimated distances respectively determined based on each of the second equivalent modulation signals is greater than the comparison distance, the number of cycles is adjusted based on a preset rule until the difference is no greater than the comparison distance.

9. The method according to claim 8, characterized in that: After determining the precise distance to the target to be measured, the method further includes: If the three precise distances obtained based on the three high-frequency modulated signals carried by the modulated signal light satisfy: The mutual difference of the precise distances is greater than a preset threshold, This measurement is invalid.

10. A phase ranging system, characterized in that: include: A transmitting module, used for transmitting modulated signal light containing high-frequency modulated signals of at least three different frequencies to a target to be measured and determining a phase difference of its echo, wherein the high-frequency band and the low-frequency band of the modulated signal are divided according to a preset standard; A simulation module, used for simulating an equivalent modulation signal based on the high-frequency modulation signals of three different frequencies carried by the modulated signal light, wherein the equivalent frequency of the equivalent modulation signal is the difference between the sum of the frequencies of the first modulation signal and the second modulation signal and twice the frequency of the third modulation signal, and the equivalent phase difference is the difference between the sum of the phase difference of the first modulation signal and the second modulation signal and twice the phase difference of the third modulation signal; A determination module is used to determine the distance to the target to be measured based on the equivalent frequency and the corresponding equivalent phase difference of the equivalent modulation signal.

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