A Phase Ranging Method and System

Abstract

The present invention relates to the technical field of laser measurement, and particularly to a phase ranging method and system. The method includes: transmitting a modulated signal light containing high-frequency modulation signals with at least three different frequencies to a target to be ranged and determining the 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; simulating an equivalent modulation signal based on the three different-frequency high-frequency modulation signals 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; determining the distance to the target to be ranged based on the equivalent frequency and the corresponding equivalent phase difference of the equivalent modulation signal. The present invention can accurately range a moving object at a long distance.

Description

Technical Field

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

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

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

[0004] The phase change is obtained by comparing the phase differences of the modulation signals carried in the modulated light acquired at different times during the round trip. However, during this time interval, the moving object will also undergo displacement, forming a motion error. And the dual-frequency laser phase rangefinder retains this motion error. Therefore, the dual-frequency laser phase rangefinder cannot precisely range long-distance moving objects. Summary of the Invention

[0005] In view of this, the purpose of the embodiments of the present invention is to provide a phase ranging method and system for precisely ranging long-distance moving objects.

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

[0007] Transmitting a modulated signal light containing high-frequency modulation signals of at least three different frequencies to a target to be ranged and determining the 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;

[0008] Based on the three different frequencies of the high-frequency modulation signals carried by the modulated signal light, simulating an equivalent modulation signal, 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] Determining the distance to the target to be ranged based on the equivalent frequency and the corresponding equivalent phase difference of the equivalent modulation signal.

[0010] Optionally, the equivalent phase difference being 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 includes:

[0011]

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

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

[0014] Modulating three different-frequency high-frequency signals on the carrier in a preset order to generate modulated signal light;

[0015] Transmitting the modulated signal light and determining the phase differences of the latest three consecutive echoes received.

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

[0017] Continuously determining the phase difference of any one of the modulation signals in the modulated signal light, and continuously determining the distance to the target to be measured for distance based on the phase difference.

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

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

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

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

[0022] Correcting the second estimated distance based on the high-frequency modulation signal to determine the accurate distance to the target to be measured for distance.

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

[0024]

[0025] where L1 is the first estimated distance to the target to be measured for distance, 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] Determine the number of cycles for the second equivalent modulation signal to transmit the first estimated distance;

[0028] Correct the first estimated distance based on the number of cycles, where,

[0029]

[0030] where 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 2 of the second equivalent modulation signals respectively, and take half of the shorter equivalent wavelength as the 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, adjust the number of cycles based on a preset rule until the difference is not greater than the comparison distance.

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

[0035] If the 3 accurate distances obtained based on the 3 high-frequency modulation signals carried by the modulated signal light satisfy:

[0036] The mutual difference of the accurate distances is greater than a preset threshold, then this measurement is invalid.

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

[0038] A transmitting module, configured to transmit a modulated signal light containing high-frequency modulation signals of at least 3 different frequencies to a target to be measured and determine the phase difference of its echo, where the high-frequency band and the low-frequency band of the modulation signal are divided according to a preset standard;

[0039] An analog module, configured to simulate an equivalent modulation signal based on the 3 different frequencies of high-frequency modulation signals carried by the modulated signal light, where 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;

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

[0041] The embodiments of the present invention include the following beneficial effects: In this embodiment, the modulated signal light containing three high-frequency modulation signals is equivalently converted into a first equivalent modulation signal with one low frequency and two second equivalent modulation signals with slightly higher frequencies. Then, based on the first equivalent modulation signal, the distance to the long-distance moving target is estimated. Based on the second equivalent modulation signal, the estimated distance is corrected for the first time. Based on the high-frequency modulation signal, the estimated distance is corrected for the second time, so as to obtain the accurate distance to the long-distance moving target. Because when measuring the distance of a moving object by using the modulated signal light containing three modulation signals, the motion errors introduced by the moving object during the measurement interval will cancel each other out, so that accurate ranging of a long-distance moving object can be realized. Further, in this embodiment, the accurate distance to the target object is gradually approximated by equivalent modulation signals with different frequencies, and the number of cycles of the propagation of the high-frequency modulation signal can be determined more accurately, 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 technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0043] Figure 1 It is a schematic diagram of the propagation of the modulated signal light containing the modulation signal and its echo;

[0044] Figure 2 It is a flowchart of a phase ranging method provided by an embodiment of the present invention;

[0045] Figure 3 It is 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 an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0047] In order to make the objectives, technical solutions and advantages of the present application more clear, the following further describes the present application in detail with reference to the 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 sequence is shown in the flowchart, in some cases, the steps shown or described may be executed in a different manner from the module division in the device or the sequence in the flowchart. Terms such as "first" and "second" in the description, claims and the above-mentioned drawings are used to distinguish similar objects and do not necessarily describe a specific order or sequence.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field 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, the described features, structures or characteristics may be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to give a full understanding of the embodiments of this application. However, those skilled in the art will realize that the technical solutions of this application can be practiced without one or more of the specific details, or other methods, components, devices, steps, etc. can be adopted. In other cases, well-known methods, devices, implementations or operations are not shown or described in detail to avoid obscuring aspects of this application.

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

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

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

[0054] Figure 1 is a propagation schematic diagram of the modulated signal light containing the modulation signal and its echo. As Figure 1 shown, the modulated signal light travels from the starting point to the ending point and then returns to the starting point, covering a total distance of 2 times the path. During this period, the modulation signal has N complete cycles and 1 incomplete cycle. Therefore, there is

[0055] 2L = (N + ΔN)λ (1);

[0056] Among them, L represents the distance from the starting point to the ending point, N represents the number of complete cycles, ΔN represents the phase mantissa and the ratio to 2π, and λ represents the wavelength of the modulation signal.

[0057] After simplification, we get:

[0058]

[0059] This is the principle of direct ranging with single-frequency laser. Among them, λ / 2 is the measuring scale length L s , that is, the measuring range. Since the number N of complete cycles is uncountable, while the phase mantissa can be measured (obtained by comparing the departure and return states of the same signal).

[0060] Therefore, when and only when N = 0, it can be known from the definition of ΔN that: At the same time, because so:

[0061] This is the formula for calculating the phase ranging distance at short distances (N = 0). Among them, is the phase difference of the modulation signal, v is the modulation signal frequency, λ is the modulation signal wavelength, and c is the speed of light.

[0062] At this time, the measuring range is λ / 2, and the accuracy is generally 1 / 1000 of the measuring range, that is, λ / 2000. It can be seen from this that the larger the measuring range, the worse the measurement accuracy; vice versa.

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

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

[0065] Adopting dual-frequency laser indirect ranging, that is, using two high-frequency modulation signals to equivalent a low-frequency modulation signal, can solve the above problems.

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

[0067]

[0068] Introduce two wavelengths to represent the same distance, that is:

[0069]

[0070] According to the componendo and dividendo theorem, we have:

[0071]

[0072] Let:

[0073]

[0074] N′ = N1 - N2 (8);

[0075] ΔN′ = ΔN1 - ΔN2 (9);

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

[0077] L = L′ s (N′ + ΔN′) (10);

[0078] Equation (10) is the principle of indirect dual - frequency laser ranging. Comparing Equation (10) with Equation (2), it can be seen that the range at this time is L′ s , and the accuracy is L′ s / 1000. And L′ s 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 difference in the number of integer cycles N′ is uncountable while the phase mantissa can be measured, the indirect ranging formula is valid if and only if N′ = 0. When and λ1 ≠ λ2, there exists N1 = N2, and at this time N′ = 0.

[0080] Indirect dual - frequency laser ranging uses two high - frequency modulation signals to equivalent a low - frequency modulation signal, estimates the distance to a long - distance target with the low - frequency modulation signal, and then obtains the accurate distance using the high - frequency modulation signal, thus achieving accurate ranging for long distances.

[0081] The equivalent frequency γ′ and equivalent phase difference of the equivalent modulation signal simulated by dual - frequency lasers with frequencies γ1, γ2 and phase differences are respectively:

[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 modulation 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 \(c = \lambda\nu\), we know that:

[0100] Substituting Eqs. (14) and (15) into Eq. (12), we get:

[0101] From Eq. (1), we know that:

[0102]

[0103] Furthermore, according to the assumed conditions, we can obtain \(N_1 > N_2 > N_3\).

[0104] When \(N_1 + N_3 - 2N_2 = 0\), Eq. (15) can be transformed into

[0105] In the above formula, \(L\) represents the detection distance, \(c\) is the speed of light, represents the phase mantissa of the first modulated signal light, represents the phase mantissa of the second modulated signal light, represents the phase mantissa of the third modulated signal light, \(\nu_1\) represents the modulation frequency of the first modulated signal light, \(\nu_2\) represents the modulation frequency of the second modulated signal light, and \(\nu_3\) represents the modulation frequency of the third modulated signal light.

[0106] The application conditions of Eq. (18):

[0107] ① Let Then If exceeds the range, then

[0108]

[0109] ② Since the distance is non - negative, so \(|\nu_1+\nu_3 - 2\nu_2|\) is required, and \(\nu_1\), \(\nu_2\), \(\nu_3\) are not in arithmetic progression;

[0110] ② where \(c_0\) is the speed of light in vacuum and \(n\) is the refractive index of air.

[0111] From the above, the equivalent frequency of the three - 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, and 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 \(\gamma_1\), \(\gamma_2\), \(\gamma_3\) respectively, and the phase differences are The equivalent frequency and equivalent phase difference of the equivalent modulation signal simulated by the laser are:

[0112] \(\gamma'=|\gamma_1+\gamma_3 - 2\gamma_2|\);

[0113]

[0114] When the modulation signals of three frequencies are transmitted at fixed time intervals, the echoes are received, processed, and the phase difference is obtained. Considering the motion error, if the modulation signal of γ1 is received at time t1, its phase difference is When the modulation signal of γ2 is received at time t2, its phase difference is When the laser of γ3 is received at t3, its phase difference is Then the equivalent phase difference of the equivalent modulation signal is:

[0115] (When )

[0116] It can be seen that the errors of the equivalent phase difference introduced by the motion error are mutually cancelled out in the three-frequency laser ranging. That is to say, based on the three-frequency laser indirect ranging, accurate ranging of moving objects can be achieved. At the same time, because the low-frequency modulation signal can also be equivalent, the effect of the two-frequency laser indirect ranging can be realized, and accurate ranging of long-distance targets can be achieved. Combining the two, the three-frequency laser indirect ranging solves the problem of accurate ranging of long-distance moving targets.

[0117] Figure 2 The figure is a flowchart of a phase ranging method provided by an embodiment of the present invention. The method includes the following steps:

[0118] S210, transmitting a modulated signal light containing high-frequency modulation signals of at least three different frequencies to a target to be ranged and determining the 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] In some embodiments of the present invention, three high-frequency signals of different frequencies are modulated on the carrier in a preset order in turn to generate a modulated signal light, and the phase differences of the latest three consecutive echoes received are determined.

[0120] In an embodiment of the present invention, the modulation signals of the three frequencies are ① 100M, ② 96M, and ③ 92.4M. Then the transmission order is ①②③①②③①②③..., and only the latest three consecutive echoes are taken for each ranging to calculate the phase difference. That is to say, the frequencies used to calculate the distance can only be the following three cases: ①②③, ②③①, ③①②;

[0121] S220, simulating an equivalent modulation signal based on the three different frequencies of the high-frequency modulation signals 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.

[0122] From Equation (18), If we let γ′ = |γ1 + γ3 - 2γ2|; then we can obtain Formally the same as the formula for direct ranging with single-frequency laser It can be considered that the modulated signal light containing three-frequency modulation signals with frequencies γ1, γ2, γ3 and phase differences respectively simulates an equivalent modulation signal. The equivalent frequency of the equivalent modulation signal: γ′ = |γ1 + γ3 - 2γ2|, and the equivalent phase difference:

[0123]

[0124] In the above example, the high-frequency modulation signals of ① 100M, ② 96M, and ③ 92.4M 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 respectively).

[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 the low-frequency modulation signal is large (for example, the equivalent modulation signal of 0.4M can measure up to more than three hundred and seventy meters at most), for common distances, the number of integer periods N of the low-frequency modulation signal propagation = 0, and we can directly use for ranging. At the same time, because the accuracy of the low-frequency modulation signal is low, the obtained distance can only be an estimate of the distance to the target to be measured.

[0127] Therefore, it is necessary to correct the estimated distance with a high-frequency modulation signal with higher accuracy. When correcting, first determine the number of periods of the high-frequency modulation signal propagation based on the estimated distance. Then based on perform precise ranging.

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

[0129] In the above example, high-frequency modulation signals of ① 100M, ② 96M, and ③ 92.4M can simulate three equivalent modulation signals of 0.4M, 11.6M, and 11.2M. Among them, 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, use the 0.4M equivalent modulation signal to estimate the distance (obtain 102 meters), and then use the 11.2M equivalent modulation signal and the 11.2M equivalent modulation signal to make a correction once.

[0130] During 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 from Equation (20). Another first correction distance can be obtained from 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 ranging is correct. If the difference between the two first correction distances is greater than half of 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 of the wavelength of the equivalent modulation signal with a shorter wavelength.

[0131] Then, based on the 3 high-frequency modulation signals, correct the first correction distance respectively to obtain the accurate distance. The method is similar to correcting the estimated distance with 2 equivalent modulation signals.

[0132] In some embodiments of the present invention, the accurate distance calculated based on the frequency of the latest received modulation signal is directly used as the output of the accurate distance. In other embodiments of the present invention, the average value of the accurate distances calculated based on the frequencies of the latest 3 received modulation signals is obtained, and the average value is used as the accurate distance.

[0133] Each step of the above ranging method has certain applicable conditions. For example, when estimating the distance, the distance cannot exceed the range of the low-frequency equivalent modulation signal. When correcting the distance, the calculation of the number of cycles must be accurate, etc. If the applicable conditions are not met, there will be a large error in the ranging result. To determine whether this measurement is valid, the present invention verifies the results obtained by accurately ranging with 3 high-frequency modulation signals respectively. The verification conditions are:

[0134] If the mutual difference of the accurate distances is greater than the preset threshold, then this 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 ranged based on the phase difference. Thus, continuous ranging of a moving target can be achieved.

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

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

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

[0139] The determining module 330 is configured to determine the distance to the target to be ranged based on the equivalent frequency and the corresponding equivalent phase difference of the equivalent modulated signal.

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

[0141] The embodiments of the present invention include the following beneficial effects: In this embodiment, based on three high-frequency lasers, one low-frequency first equivalent modulated signal and two second equivalent modulated signals with slightly higher frequencies are equivalent. Then, based on the first equivalent modulated signal, the distance to a long-distance moving target is estimated. Based on the second equivalent modulated signal, the estimated distance is corrected for the first time. Based on the high-frequency laser, the estimated distance is corrected for the second time, so as to obtain the accurate distance to the long-distance moving target. Because when ranging a moving object with lasers of three frequencies, the motion errors introduced by the moving object during the measurement interval will cancel each other out, thus enabling accurate ranging of a long-distance moving object; further, in this embodiment, the target object is gradually approximated through equivalent modulated signals of different frequencies, because the number of cycles of high-frequency laser propagation can be determined more accurately, improving the efficiency of correcting the estimated distance and obtaining the accurate distance.

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

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

[0144] It should be understood that, in this application, the terms "including" and "having", and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products, or devices. "At least one (item)" means one or more, and "a plurality" means two or more. "And / or" is used to describe the association relationship of associated objects and indicates that three relationships may exist. For example, "A and / or B" may mean: only A exists, only B exists, and both A and B exist simultaneously. Here, A and B can be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship. "At least one of the following (items)" or a similar expression means any combination of these items, including any combination of single items (items) or plural items (items). For example, at least one of a, b, or c may mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

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

[0146] If the above-mentioned 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 this application, in essence, or the part that contributes to the prior art, or all or part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes multiple instructions for causing 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 methods described in each embodiment of this application. The aforementioned storage medium includes: various media that can store programs, such as USB flash drives, mobile hard disks, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical discs.

[0147] The preferred embodiments of the embodiments of the present application have been described above with reference to the accompanying drawings, which do not limit the scope of rights of the embodiments of the present application. Any modifications, equivalent replacements, and improvements made by those skilled in the art without departing from the scope and essence of the embodiments of the present application shall fall within the scope of rights of the embodiments of the present application.

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; Determining the distance to the target to be measured based on the equivalent frequency of the equivalent modulation signal and the corresponding equivalent phase difference; specifically comprising: Simulating three equivalent modulation signals based on the modulated signal light, wherein the first equivalent modulation signal with the lowest equivalent frequency is in a low frequency band; Determining a first estimated distance to the target to be measured based on the first equivalent modulation signal; specifically comprising: ； Wherein, L1 is the first estimated distance to the target to be measured, C is the speed of light in the ranging environment, is the equivalent frequency of the first equivalent modulation signal, is the equivalent phase difference; The first estimated distance is corrected based on the remaining two second equivalent modulation signals to determine the second estimated distance to the target to be measured; specifically comprising: 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, is the equivalent frequency of the second equivalent modulation signal, is with The corresponding equivalent phase difference, N is the number of cycles, and λ is the equivalent wavelength of the second equivalent modulation signal; The second estimated distance is corrected based on the high-frequency modulation signal to determine the precise distance to the target to be measured.

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 the phase differences of the first modulation signal, the second modulation signal and the third modulation signal respectively, and k is an integer.

3. The method according to claim 2, characterized in that: The method 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 1, 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.

6. The method according to claim 5, 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.

7. 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; specifically used for: Simulating three equivalent modulation signals based on the modulated signal light, wherein the first equivalent modulation signal with the lowest equivalent frequency is in a low frequency band; Determining a first estimated distance to the target to be measured based on the first equivalent modulation signal; specifically comprising: ； Wherein, L1 is the first estimated distance to the target to be measured, C is the speed of light in the ranging environment, is the equivalent frequency of the first equivalent modulation signal, is the equivalent phase difference; The first estimated distance is corrected based on the remaining two second equivalent modulation signals to determine the second estimated distance to the target to be measured; specifically comprising: 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, is the equivalent frequency of the second equivalent modulation signal, is with The corresponding equivalent phase difference, N is the number of cycles, and λ is the equivalent wavelength of the second equivalent modulation signal; The second estimated distance is corrected based on the high-frequency modulation signal to determine the precise distance to the target to be measured.

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