A polarization modulation fast ranging method, system, device and storage medium

Abstract

The application relates to the technical field of optical detection, in particular to a polarization modulation fast ranging method, system, device and storage medium, the method comprising the following steps: acquiring a modulation frequency corresponding to a light intensity minimum value on a sweep curve and a neighborhood as a fine sweep frequency range; taking a fine sweep frequency start point and an end point as a first frequency point and a second frequency point; starting forward and reverse collection of corresponding voltage values with the first frequency point and the second frequency point as start points and a half of a modulation frequency difference value corresponding to the two points as a step; calculating a straight line slope between a collection point and an adjacent point by using the voltage value and the modulation frequency, and judging a collection direction and the step; stopping collection when a difference value between the second frequency point and the first frequency point is less than a preset threshold value, taking a half of the difference value as an in-phase frequency, and continuing bidirectional collection if not; and calculating a distance to be measured based on the in-phase frequency. The polarization modulation fast ranging method provided by the application can solve the problems of inaccurate in-phase frequency extraction and slow measurement speed in polarization modulation ranging.

Description

Technical Field

[0001] This application relates to the field of optical detection technology, and in particular to a polarization modulation fast ranging method, system, device and storage medium. Background Technology

[0002] Large-scale, high-precision absolute ranging technology has wide applications in aerospace, large equipment manufacturing, and other fields. Traditional laser ranging technologies include time-of-flight (TOF), phase-array, and interferometric methods. TOF offers a large ranging range and simple structure, but its accuracy is limited by the response speed of electronic devices, making it unsuitable for high-precision ranging. Phase-array ranging can achieve sub-millimeter accuracy but suffers from ambiguity. Interferometric ranging can achieve nanometer-scale accuracy but can only perform relative distance calculations. Femtosecond optical comb ranging offers high accuracy, but its complex system and high maintenance costs make it unsuitable for engineering applications.

[0003] Polarization modulation ranging methods eliminate the need for phase detection, avoid ambiguity, and achieve high-resolution, high-precision ranging. This method utilizes a phase modulator to perform frequency-sweeping polarization modulation and demodulation on the measurement light traveling to and from the target. Polarization interference is used to convert the phase difference between the outgoing and returning waves into light intensity information. The distance to be measured is calculated by extracting the modulation frequency (i.e., the in-phase frequency) corresponding to the minimum light intensity value in the fully demodulated state.

[0004] However, in-phase frequency extraction requires small-step frequency sweeping within the sweeping interval, followed by fitting and solving the in-phase frequency after obtaining the sweeping curve, resulting in a slow ranging speed. Furthermore, in-phase frequency extraction at the light intensity minimum is affected by background noise, leading to inaccurate extraction and impacting ranging accuracy. Summary of the Invention

[0005] This application provides a polarization modulation fast ranging method, system, device, and storage medium to solve the problems of inaccurate extraction of in-phase frequency and slow measurement speed in polarization modulation ranging.

[0006] To address the aforementioned technical problems, in a first aspect, embodiments of this application provide a polarization modulation fast ranging method, comprising the following steps: First, a coarse frequency sweep is performed within a frequency sweep range to obtain the modulation frequency corresponding to the minimum light intensity on the modulation frequency-light intensity curve; next, based on the modulation frequency and its neighborhood, a first frequency point and a second frequency point are obtained; and based on the first frequency point and the second frequency point, a fine frequency sweep range is obtained, and a fine frequency sweep is performed within the fine frequency sweep range; then, the difference between the second frequency point and the first frequency point is calculated; and voltage values ​​corresponding to the modulation frequency at different sampling points are collected, starting from the first frequency point and the second frequency point respectively, with a step of half the difference; Based on the voltage value at the acquisition point and the modulation frequency, the slope of the straight line between the acquisition point and its adjacent points is calculated. When the slope of the straight line between the acquisition point and its adjacent points changes from negative to positive, the process returns to the first frequency point and begins forward acquisition calculation with half of the current step. When the slope of the straight line between the acquisition point and its adjacent points changes from positive to negative, the process returns to the second frequency point and begins reverse acquisition calculation with half of the current step. It is determined whether the difference between the second frequency point and the first frequency point is less than a preset threshold. If so, acquisition stops; if not, bidirectional acquisition calculation continues. Finally, the distance to be measured is calculated based on the in-phase frequency.

[0007] In some exemplary embodiments, when the first frequency point is taken as the starting point, the slope of the straight line between the acquisition point and the adjacent point includes a first slope and a second slope; the first slope is the slope of the straight line between the previous acquisition point and the first frequency point; the second slope is the slope of the straight line between the next acquisition point and the first frequency point; when the first frequency point is taken as the starting point and the slope of the straight line between the acquisition point and the adjacent point changes from negative to positive, the first frequency point is returned, and forward acquisition calculation begins with half of the current step, including: starting forward acquisition calculation with the first frequency point as the starting point; if both the first slope and the second slope change from negative to positive, the first frequency point is returned, and the first and second slopes are re-acquired and calculated with half of the current step as the step; otherwise, the first frequency point is updated.

[0008] In some exemplary embodiments, when the second frequency point is taken as the starting point, the slope of the straight line between the acquisition point and the adjacent point includes a first slope and a second slope; the first slope is the slope of the straight line between the previous acquisition point and the first frequency point; the second slope is the slope of the straight line between the next acquisition point and the first frequency point; when the second frequency point is taken as the starting point and the slope of the straight line between the acquisition point and the adjacent point changes from positive to negative, the process returns to the second frequency point and reverses the acquisition calculation starting from half of the current step, including: starting the reverse acquisition calculation starting from the second frequency point; if both the first slope and the second slope change from positive to negative, the process returns to the second frequency point, re-acquires and calculates the first slope and the second slope with a step size of half of the current step, otherwise the second frequency point is updated.

[0009] In some exemplary embodiments, the in-phase frequency is half the difference between the second frequency point and the first frequency point.

[0010] In some exemplary embodiments, the value of the first frequency point is the difference between the minimum value and the neighborhood, and the value of the second frequency point is the sum of the minimum value and the neighborhood.

[0011] In some exemplary embodiments, calculating the distance to be measured based on the in-phase frequency includes: acquiring the in-phase frequency at two consecutive minimum light intensity points; and calculating the distance to be measured based on the correspondence between the modulation frequency of adjacent minimum light intensity points and the distance to be measured.

[0012] In some exemplary embodiments, the correspondence is as follows:

[0013]

[0014]

[0015]

[0016] Where L is the distance to be measured; f1 and f2 are the in-phase frequencies at two consecutive minimum light intensities; [] represents the rounding operation; and c is the speed of light.

[0017] Secondly, this application also provides a polarization modulation fast ranging system, including: a coarse frequency sweep module, a fine frequency sweep module, and a data processing module; the coarse frequency sweep module is used to perform a coarse frequency sweep within the sweep range to obtain the modulation frequency corresponding to the minimum light intensity on the modulation frequency-light intensity curve; the fine frequency sweep module is used to obtain a first frequency point and a second frequency point based on the modulation frequency and the neighborhood; and based on the first frequency point and the second frequency point, obtain a fine frequency sweep range, and perform a fine frequency sweep within the fine frequency sweep range; the data processing module includes a first frequency point and a second frequency point calculation module, a judgment module, and a distance to be measured calculation module; wherein, the first frequency point and the second frequency point calculation module is used to calculate the difference between the second frequency point and the first frequency point; taking the first frequency point and the second frequency point as starting points respectively, and using the difference... Half of the value is the voltage value corresponding to the modulation frequency at different acquisition points in step acquisition; based on the voltage value of the acquisition point and the modulation frequency, the slope of the straight line between the acquisition point and the adjacent point is calculated; when the first frequency point is taken as the starting point and the slope of the straight line between the acquisition point and the adjacent point changes from negative to positive, the first frequency point is returned and forward acquisition calculation begins with half of the current step; when the second frequency point is taken as the starting point and the slope of the straight line between the acquisition point and the adjacent point changes from positive to negative, the second frequency point is returned and reverse acquisition calculation begins with half of the current step; the judgment module is used to determine whether the difference between the second frequency point and the first frequency point is less than a preset threshold; if yes, acquisition stops; if no, bidirectional acquisition calculation continues; the distance to be measured calculation module is used to calculate the distance to be measured based on the in-phase frequency.

[0018] In addition, this application also provides an electronic device, including: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the above-described polarization modulation fast ranging method.

[0019] In addition, this application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described polarization modulation fast ranging method.

[0020] The technical solution provided in this application has at least the following advantages:

[0021] This application provides a polarization modulation fast ranging method, system, device, and storage medium. The method includes the following steps: First, a coarse frequency sweep is performed within the frequency sweep range to obtain the modulation frequency corresponding to the minimum light intensity on the modulation frequency-light intensity curve; then, based on the modulation frequency and the neighborhood, a first frequency point and a second frequency point are obtained; and based on the first frequency point and the second frequency point, a fine frequency sweep range is obtained, and a fine frequency sweep is performed within the fine frequency sweep range; next, the difference between the second frequency point and the first frequency point is calculated; starting from the point where the first frequency point is located, forward acquisition is performed in half the step of the difference, and the slope of the straight line between the acquisition point and the adjacent point is calculated; simultaneously, starting from the point where the second frequency point is located, reverse acquisition is performed in half the step of the difference, and the slope of the straight line between the acquisition point and the adjacent point is calculated; and based on the slope, the positive and negative signs of the first slope and the second slope are used to determine the acquisition direction; then, it is determined whether the difference between the second frequency point and the first frequency point is less than a preset threshold. If so, acquisition is stopped, and the in-phase frequency is obtained; if not, bidirectional acquisition continues; finally, the distance to be measured is calculated based on the in-phase frequency.

[0022] The polarization modulation fast ranging method provided in this application first quickly locates the region near the in-phase frequency point, reducing the number of sweep points and shortening the sweep time. It then rapidly narrows down the range of the in-phase frequency by calculating the slope of the straight line between the acquisition point and adjacent points. Next, using a first frequency point and a second frequency point as starting points, with half the difference in modulation frequencies between the two points as the initial step, it simultaneously approaches the in-phase frequency point bidirectionally, reducing the approach time by changing the step size. Finally, when the difference between the second frequency point and the first frequency point is less than a preset threshold, the in-phase frequency is obtained, and the high-precision, fast in-phase frequency extraction algorithm ends. The polarization modulation fast ranging method provided in this application solves the problem of inaccurate in-phase frequency extraction under background noise, while also considering ranging speed, thus improving measurement accuracy and the stability of the measurement system. Attached Figure Description

[0023] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments, and unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0024] Figure 1 A schematic flowchart of a polarization modulation fast ranging method provided in an embodiment of this application;

[0025] Figure 2 This is a schematic diagram of a polarization modulation fast ranging device provided in an embodiment of this application;

[0026] Figure 3 This is a schematic diagram of the frequency sweep curve collected according to an embodiment of this application;

[0027] Figure 4 A schematic flowchart of a polarization modulation fast ranging method provided for another embodiment of this application;

[0028] Figure 5 This is a schematic diagram of a method for determining the minimum value using a coarse frequency sweep according to an embodiment of this application;

[0029] Figure 6 This is a schematic diagram of a method for extracting in-phase frequencies using a fine-scan frequency method according to an embodiment of this application;

[0030] Figure 7 This is a schematic diagram of the structure of a polarization modulation fast ranging system provided in an embodiment of this application;

[0031] Figure 8 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0032] As the background technology shows, existing polarization modulation ranging methods require small-step frequency sweeping within a frequency sweep interval to extract the in-phase frequency. After obtaining the sweep curve, the in-phase frequency is fitted and solved, resulting in a slow ranging speed. Furthermore, the extraction of the in-phase frequency at the minimum light intensity is affected by background noise, leading to inaccurate extraction and impacting ranging accuracy.

[0033] To address the aforementioned technical problems, this application provides a polarization modulation fast ranging method, comprising the following steps: First, a coarse frequency sweep is performed within the sweep range to obtain the modulation frequency corresponding to the minimum light intensity on the modulation frequency-light intensity curve; then, based on the modulation frequency and the neighborhood, a first frequency point and a second frequency point are obtained; and based on the first frequency point and the second frequency point, a fine frequency sweep range is obtained, and a fine frequency sweep is performed within the fine frequency sweep range; next, the difference between the second frequency point and the first frequency point is calculated; starting from the point where the first frequency point is located, forward acquisition is performed in steps of half the difference, and the slope of the line connecting the acquisition point and the adjacent point is calculated; starting from the point where the second frequency point is located, reverse acquisition is performed in steps of half the difference, and the slope of the line connecting the acquisition point and the adjacent point is calculated; and based on the slope, the acquisition directions of the first frequency point and the second frequency point are obtained; then, it is determined whether the difference between the second frequency point and the first frequency point is less than a preset threshold. If so, acquisition is stopped, and the in-phase frequency is obtained; if not, bidirectional acquisition continues; finally, the distance to be measured is calculated based on the in-phase frequency. This application provides a polarization modulation fast ranging method to solve the problem of inaccurate extraction of in-phase frequency under background noise, while also taking into account ranging speed, thereby improving measurement accuracy and the stability of the measurement system.

[0034] The embodiments of this application will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this application to facilitate a better understanding of the application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0035] See Figure 1 This application provides a polarization modulation fast ranging method, including the following steps:

[0036] Step S1: Perform a coarse frequency sweep within the frequency sweep range to obtain the modulation frequency corresponding to the minimum light intensity on the modulation frequency-light intensity curve.

[0037] Step S2: Based on the modulation frequency and the neighborhood, obtain the first frequency point and the second frequency point; and based on the first frequency point and the second frequency point, obtain the fine sweep frequency range, and perform fine sweep frequency within the fine sweep frequency range.

[0038] Step S3: Calculate the difference between the second frequency point and the first frequency point; taking the first frequency point and the second frequency point as the starting point respectively, and stepping by half of the difference, collect the voltage value corresponding to the modulation frequency at different collection points.

[0039] Step S4: Based on the voltage value of the acquisition point and the modulation frequency, calculate the slope of the straight line between the acquisition point and the adjacent points.

[0040] Step S5: When the first frequency point is taken as the starting point and the slope of the straight line between the sampling point and the adjacent point changes from negative to positive, return to the first frequency point and start forward sampling calculation with half of the current step; when the second frequency point is taken as the starting point and the slope of the straight line between the sampling point and the adjacent point changes from positive to negative, return to the second frequency point and start reverse sampling calculation with half of the current step.

[0041] Step S6: Determine whether the difference between the second frequency point and the first frequency point is less than a preset threshold; if yes, stop the acquisition; if no, continue bidirectional acquisition and calculation.

[0042] Step S7: Calculate the distance to be measured based on the in-phase frequency.

[0043] This application provides a rapid polarization modulation ranging method. The method first performs a coarse frequency sweep within a frequency sweep range to obtain the modulation frequency corresponding to the minimum light intensity on the modulation frequency-light intensity curve. Then, a fine frequency sweep is performed within the neighborhood of the modulation frequency corresponding to the minimum light intensity, with the start and end points of the fine sweep serving as the first and second frequency points, respectively. Next, starting from the first and second frequency points respectively, and using half the difference in modulation frequencies between the two points as a step, the corresponding voltage values ​​are acquired in both forward and reverse directions. Specifically, when starting from the first frequency point, the method... Half of the difference is used as the step to start forward acquisition of voltage values ​​corresponding to the modulation frequencies at different acquisition points. When starting from the second frequency point, half of the difference is used as the step to start reverse acquisition of voltage values ​​corresponding to the modulation frequencies at different acquisition points. Then, the slope of the straight line between the acquisition point and adjacent points is calculated using the voltage value and modulation frequency to determine the acquisition direction and step. Acquisition stops when the difference between the second frequency point and the first frequency point is less than a preset threshold, and half of the difference is taken as the in-phase frequency; otherwise, bidirectional acquisition continues. Finally, the distance to be measured is calculated based on the in-phase frequency. This application solves the problems of inaccurate in-phase frequency extraction and slow measurement speed in polarization modulation ranging by providing a rapid polarization modulation ranging method.

[0044] This application employs a polarization modulation fast ranging device for in-phase frequency extraction. This device, such as... Figure 2 As shown, its structure includes: light source 1, PBS 2, modulator 3, quarter wave plate 4, mirror 5, lock-in amplifier 6, detector 7, signal source 8, function generator 9, and computer 10.

[0045] The working principle of this device is as follows: Polarized light emitted from light source 1 is modulated by PBS2 and then enters modulator 3 for photoelectric modulation. The modulated light passes through quarter-wave plate 4 to reflector 5 and returns to modulator 3 for demodulation. The demodulated light reaches PBS2 and undergoes polarization interference. The interference signal is photoelectrically converted by detector 7 and then converted by A / D converter to become the input signal of lock-in amplifier 6. Two sinusoidal signals are generated by function generator 9. One signal is converted by A / D module and used as the reference signal of lock-in amplifier 6. The other signal is used as the primary modulation signal of the signal. The reference signal and the input signal are phase-sensitively detected and low-pass filtered in lock-in amplifier 6 before being output. The output signal is then sent to computer 10 for in-phase frequency extraction.

[0046] This application uses the output signal of the function generator 9 in the above-mentioned polarization modulation ranging device as the message signal of the primary modulation signal, and also as the reference signal of the lock-in amplifier 6:

[0047] v Ω =V Ωm cos(Ωt+θ)(1a)

[0048] In equation (1a), VΩm Ω is the modulation voltage for frequency modulation, θ is the frequency of the modulation signal, and θ is the initial phase of the modulation signal.

[0049] The signal received by detector 7 is used as the input signal for lock-in amplifier 6:

[0050]

[0051] In equation (2a), E0 is the amplitude of the linearly polarized light, M is the electro-optic modulation depth, and f c The modulation frequency is denoted by Δf, and the maximum frequency deviation is denoted by Δf. The probe signal and reference signal are simultaneously input into lock-in amplifier 6. After phase-sensitive detection and low-pass filtering, only the DC component is retained, and the output signal is:

[0052]

[0053] Because the sine function is periodic, the distance to be measured has multiple solutions. Therefore, it is necessary to obtain the light intensity signals at multiple modulation frequencies through continuous frequency sweeping to obtain a single solution for the distance. A schematic diagram of obtaining the modulation frequency and probe light intensity through frequency sweeping is shown below. Figure 3 As shown, the frequencies f1 and f2 corresponding to two consecutive minimum light intensity values ​​are measured. The correspondence between the frequencies of adjacent minimum light intensity points and the distance to be measured is as follows:

[0054]

[0055]

[0056]

[0057] Solving N by combining formulas (1) and (2) and then substituting the result into formula (3) will yield the distance to be measured.

[0058] In formula (3), L is the distance to be measured; f1 and f2 are the in-phase frequencies (adjacent in-phase frequencies) at two consecutive minimum light intensity values; [] is the rounding operation; and c is the speed of light.

[0059] The polarization modulation fast ranging method provided in this application will be described in detail below through specific embodiments.

[0060] This application adopts the following... Figure 2The polarization modulation ranging device shown is used for ranging. Light source 1 is a 1550nm laser. The primary modulation signal has a message signal frequency of 2kHz and an amplitude of 3vpp, while the carrier signal has a frequency of 50kHz and an amplitude of 18dB. The primary modulation signal frequency deviation is 1kHz. The secondary modulation signal coarse sweep frequency range is 800–900MHz. The lock-in amplifier low-pass filter time constant is 500µs, and the descent is 6dB / oct. The lock-in amplifier acquisition card has a acquisition frequency of 0.1s, a coarse sweep frequency step of 100kHz, a neighborhood ΔF of 100kHz, and a fine sweep frequency step of 100Hz.

[0061] Figure 3 This is a schematic diagram of a frequency sweep curve obtained according to an embodiment of this application; this application addresses... Figure 3 The frequency sweep curve shown illustrates a polarization modulation fast ranging method that balances in-phase frequency accuracy and speed. A flowchart of a specific embodiment is shown below. Figure 4 As shown below, the specific steps of the polarization modulation ranging method provided in this application will be described in detail.

[0062] First, a coarse frequency sweep is performed within the sweep range to quickly extract the modulation frequency f corresponding to the minimum light intensity value of the modulation frequency-light intensity curve during the coarse frequency sweep.

[0063] Next, based on the modulation frequency and the neighborhood, a first frequency point and a second frequency point are obtained; and based on the first frequency point and the second frequency point, a fine frequency sweep range is obtained, and fine frequency sweeping is performed within this range. In some embodiments, the first frequency point is the difference between the modulation frequency and the neighborhood, and the second frequency point is the sum of the modulation frequency and the neighborhood. Specifically, with the point where the modulation frequency f is located as the center point and ΔF as the neighborhood, fine frequency sweeping is performed within the range of f-ΔF to f+ΔF. This allows for rapid location of the region near the in-phase frequency point, reducing the number of sweep points and shortening the sweeping time. For details, please refer to [link to relevant documentation]. Figure 5 .like Figure 5 As shown, the point where the first frequency point is located is represented by F1, the point where the second frequency point is located is represented by F2, and the fine sweep frequency range is from f-ΔF to f+ΔF.

[0064] In some embodiments, the slope of the straight line in step S4 includes a first slope and a second slope; the first slope is the slope of the straight line between the acquisition point and the previous acquisition point; the second slope is the slope of the straight line between the acquisition point and the next acquisition point; based on the first slope and the second slope, the acquisition direction of the first frequency point and the second frequency point is obtained, including: starting the forward acquisition calculation from the first frequency point; if both the first slope and the second slope change from negative to positive, then return to the first frequency point, re-acquire and calculate the slope with half of the current step size; otherwise, update the first frequency point; at the same time, starting the reverse acquisition calculation from the second frequency point; if both the first slope and the second slope change from positive to negative, then return to the second frequency point, re-acquire and calculate the slope with half of the current step size; otherwise, update the second frequency point;

[0065] Repeatedly calculate the difference between the second and first frequency points, using the first and second frequency points as starting points, with half of the difference as the step for bidirectional acquisition. Specifically, define f-ΔF as the first frequency F1, f+ΔF as the second frequency F2, the slope of the line connecting the center frequency point (A1) and the previous acquisition point (A0) as k1, and the slope of the line connecting the center frequency point (A1) and the next acquisition point (A2) as k2. See details below. Figure 6 .

[0066] Calculate the difference Δf between the second frequency point F2 and the first frequency point F1, where Δf = F2 - F1. Starting from the point where the first frequency F1 is located, perform forward sampling in steps of Δf / 2. Starting from the point where the second frequency F2 is located, perform reverse sampling in steps of Δf / 2. Calculate the slopes k1 and k2 of the lines connecting the sampling point to adjacent points, and use the slopes k1 and k2 to determine the sampling direction.

[0067] In some embodiments, forward acquisition and calculation begin from a first frequency point. If both the first slope and the second slope change from negative to positive, the process returns to the first frequency point, re-acquires and calculates the slope using half of the current step size; otherwise, the first frequency point is updated. Simultaneously, reverse acquisition and calculation begin from a second frequency point. If both the first slope and the second slope change from positive to negative, the process returns to the second frequency point, re-acquires and calculates the slope using half of the current step size; otherwise, the second frequency point is updated.

[0068] Repeatedly calculate the difference between the second and first frequency points, using both the first and second frequency points as starting points, and take half of the difference as the step for bidirectional acquisition. The advantage of this step is that it simultaneously and bidirectionally approximates the in-phase frequency point, and reduces the approximation time by changing the step size.

[0069] When the difference between the second frequency point and the first frequency point is less than the set threshold, the acquisition stops; half of the difference between the second frequency point and the first frequency point is taken as the in-phase frequency, and the high-precision and fast in-phase frequency extraction algorithm ends.

[0070] In some embodiments, the distance to be measured is calculated based on the in-phase frequency, including: obtaining the in-phase frequency at two consecutive light intensity minima; based on the correspondence between the frequencies of adjacent light intensity minima and the distance to be measured, as shown in the above formulas (1) to (2), the distance to be measured can be solved by solving formulas (1) and (2) simultaneously and substituting them into formula (3).

[0071] Therefore, the polarization modulation fast ranging method provided in this application utilizes coarse frequency sweeping to quickly locate frequencies near the in-phase frequency, and bidirectionally approximates the in-phase frequency within the fine frequency sweeping range. When extracting the in-phase frequency, it can simultaneously balance accuracy and speed, which is of great significance for improving the performance of ranging systems. Furthermore, the polarization modulation fast ranging method provided in this application can filter out harmonics and noise components in the signal, significantly improving the signal-to-noise ratio.

[0072] See Figure 7 This application also provides a polarization modulation fast ranging system, including: a coarse frequency sweep module 101, a fine frequency sweep module 102, and a data processing module 103; the coarse frequency sweep module 101 is used to perform coarse frequency sweep within the sweep range to obtain the modulation frequency corresponding to the minimum light intensity on the modulation frequency-light intensity curve; the fine frequency sweep module 102 is used to obtain a first frequency point and a second frequency point according to the modulation frequency and the neighborhood; and based on the first frequency point and the second frequency point, obtain the fine frequency sweep range, and perform fine frequency sweep within the fine frequency sweep range.

[0073] The data processing module 103 includes a first frequency point and a second frequency point calculation module 1031, a judgment module 1032, and a distance calculation module 1033; wherein, the first frequency point and second frequency point calculation module 1031 is used to calculate the difference between the second frequency point and the first frequency point; taking the first frequency point and the second frequency point as starting points respectively, and taking half of the difference as a step, the voltage value corresponding to the modulation frequency at different acquisition points is collected; based on the voltage value of the acquisition point and the modulation frequency, the slope of the straight line between the acquisition point and the adjacent point is calculated; when the first frequency point is taken as the starting point, and the acquisition point and the... When the slope of the straight line between adjacent points changes from negative to positive, the system returns to the first frequency point and begins forward acquisition calculation with half of the current step. When the system starts from the second frequency point and the slope of the straight line between the acquisition point and the adjacent point changes from positive to negative, the system returns to the second frequency point and begins reverse acquisition calculation with half of the current step. The judgment module 1032 is used to determine whether the difference between the second frequency point and the first frequency point is less than a preset threshold. If so, the acquisition stops; if not, the bidirectional acquisition calculation continues. The distance to be measured calculation module 1033 is used to calculate the distance to be measured based on the in-phase frequency.

[0074] See Figure 8 Another embodiment of this application provides an electronic device, including: at least one processor 110; and a memory 111 communicatively connected to the at least one processor; wherein the memory 111 stores instructions executable by the at least one processor 110, the instructions being executed by the at least one processor 110 to enable the at least one processor 110 to perform any of the above method embodiments.

[0075] The memory 111 and processor 110 are connected via a bus. This bus can include any number of interconnecting buses and bridges, connecting various circuits of one or more processors 110 and the memory 111. The bus can also connect various other circuits, such as peripheral devices, voltage regulators, and power management circuits, which are well-known in the art and therefore will not be further described here. A bus interface provides an interface between the bus and the transceiver. The transceiver can be a single element or multiple elements, such as multiple receivers and transmitters, providing a unit for communicating with various other devices over a transmission medium. Data processed by processor 110 is transmitted over a wireless medium via an antenna, which further receives data and transmits it to processor 110.

[0076] Processor 110 is responsible for managing the bus and general processing, and can also provide various functions, including timing, peripheral interfaces, voltage regulation, power management, and other control functions. Memory 111 can be used to store data used by processor 110 during operation.

[0077] Another embodiment of this application relates to a computer-readable storage medium storing a computer program. When executed by a processor, the computer program implements the method embodiments described above.

[0078] That is, those skilled in the art will understand that all or part of the steps in the methods of the above embodiments can be implemented by a program instructing related hardware. This program is stored in a storage medium and includes several instructions to cause a device (which may be a microcontroller, chip, etc.) or processor to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0079] Based on the above technical solutions, embodiments of this application provide a polarization modulation fast ranging method, system, device, and storage medium. The method includes the following steps: First, a coarse frequency sweep is performed within the frequency sweep range to obtain the modulation frequency corresponding to the minimum light intensity on the modulation frequency-light intensity curve; Next, based on the modulation frequency and the neighborhood, a first frequency point and a second frequency point are obtained; and based on the first frequency point and the second frequency point, a fine frequency sweep range is obtained, and a fine frequency sweep is performed within the fine frequency sweep range; Next, the difference between the second frequency point and the first frequency point is calculated; Starting from the point where the first frequency point is located, forward acquisition is performed in half the step of the difference, and reverse acquisition is performed starting from the point where the second frequency point is located in half the step of the difference; The slope of the straight line between the acquisition point and the adjacent point is calculated, and based on the slope, the positive and negative signs of the first slope and the second slope are used to determine the acquisition direction; Then, it is determined whether the difference between the second frequency point and the first frequency point is less than a preset threshold. If so, acquisition is stopped, and the in-phase frequency is obtained; if not, bidirectional acquisition continues; Finally, the distance to be measured is calculated based on the in-phase frequency.

[0080] The polarization modulation fast ranging method provided in this application quickly locates the region near the in-phase frequency point, reducing the number of sweep points and shortening the sweep time. It also rapidly narrows down the range of the in-phase frequency by using the slope of the straight line between the acquisition point and adjacent points. Then, starting from the first and second frequency points, it simultaneously approaches the in-phase frequency point bidirectionally, reducing the approach time by changing the step size. Finally, when the difference between the second and first frequency points is less than a preset threshold, the in-phase frequency is obtained, and the high-precision, fast in-phase frequency extraction algorithm ends. The polarization modulation fast ranging method provided in this application solves the problem of inaccurate in-phase frequency extraction under background noise, while also considering ranging speed, thus improving measurement accuracy and the stability of the measurement system.

[0081] Those skilled in the art will understand that the above-described embodiments are specific examples of implementing this application, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of this application. Any person skilled in the art can make their own modifications and alterations without departing from the spirit and scope of this application; therefore, the scope of protection of this application should be determined by the scope defined in the claims.

Claims

1. A polarization modulation fast ranging method, characterized in that, include: Perform a coarse frequency sweep within the frequency sweep range to obtain the modulation frequency corresponding to the minimum light intensity on the modulation frequency-light intensity curve. Based on the modulation frequency and the neighborhood, a first frequency point and a second frequency point are obtained; the value of the first frequency point is the difference between the minimum light intensity and the neighborhood, and the value of the second frequency point is the sum of the minimum light intensity and the neighborhood; and based on the first frequency point and the second frequency point, a fine frequency sweep range is obtained, and fine frequency sweep is performed within the fine frequency sweep range; Calculate the difference between the second frequency point and the first frequency point; take the first frequency point and the second frequency point as the starting point respectively, and step by half of the difference to collect the voltage value corresponding to the modulation frequency at different collection points; Based on the voltage value at the sampling point and the modulation frequency, calculate the slope of the straight line between the sampling point and the adjacent point; When the first frequency point is taken as the starting point and the slope of the straight line between the sampling point and the adjacent point changes from negative to positive, the system returns to the first frequency point and starts forward sampling and calculation with half of the current step. When the second frequency point is taken as the starting point and the slope of the straight line between the sampling point and the adjacent point changes from positive to negative, the system returns to the second frequency point and starts reverse sampling and calculation with half of the current step. Determine whether the difference between the second frequency point and the first frequency point is less than a preset threshold. If yes, stop data collection; if no, continue bidirectional data collection and calculation. The distance to be measured is calculated based on the in-phase frequency; the in-phase frequency is half of the difference between the second frequency point and the first frequency point.

2. The polarization modulation fast ranging method according to claim 1, characterized in that, When the first frequency point is taken as the starting point, the slope of the straight line between the sampling point and the adjacent point includes a first slope and a second slope; the first slope is the slope of the straight line between the previous sampling point and the first frequency point; the second slope is the slope of the straight line between the next sampling point and the first frequency point. When data acquisition begins at the first frequency point as the starting point for forward scanning, and the slope of the straight line between the acquisition point and its adjacent points changes from negative to positive, the process returns to the first frequency point and begins forward acquisition calculation at half the current step size, including: Starting from the first frequency point, forward acquisition and calculation begin. If both the first slope and the second slope change from negative to positive, return to the first frequency point, re-acquire and calculate the first slope and the second slope with a step size of half the current step. Otherwise, update the first frequency point.

3. The polarization modulation fast ranging method according to claim 1, characterized in that, When the second frequency point is taken as the starting point, the slope of the straight line between the sampling point and the adjacent point includes a first slope and a second slope; the first slope is the slope of the straight line between the previous sampling point and the first frequency point; the second slope is the slope of the straight line between the next sampling point and the first frequency point. When data acquisition begins at the second frequency point and the slope of the straight line between the acquisition point and its adjacent point changes from positive to negative, the process returns to the second frequency point and begins reverse acquisition calculation at half the current step size, including: Starting from the second frequency point, reverse acquisition and calculation begin. If both the first slope and the second slope change from positive to negative, return to the second frequency point, reacquire and calculate the first slope and the second slope with a step size of half the current step. Otherwise, update the second frequency point.

4. The polarization modulation fast ranging method according to claim 1, characterized in that, The calculation of the distance to be measured based on the in-phase frequency includes: Obtain the in-phase frequencies at two consecutive minimum light intensity values; The distance to be measured is calculated based on the correspondence between the frequencies of adjacent minimum light intensity points and the distance to be measured.

5. The polarization modulation fast ranging method according to claim 4, characterized in that, The correspondence is as follows: （1） （2） （3） Where L is the distance to be measured; f 1. f 2 represents the in-phase frequencies at two consecutive minimum light intensities; [ ] represents the rounding operation; c It is the speed of light.

6. A polarization modulation fast ranging system, the system being used to implement the polarization modulation fast ranging method as described in any one of claims 1 to 5, characterized in that, include: Coarse frequency sweep module, fine frequency sweep module, and data processing module; The coarse frequency sweep module is used to perform a coarse frequency sweep within the sweep range to obtain the modulation frequency corresponding to the minimum value of light intensity on the modulation frequency-light intensity curve. The fine frequency sweep module is used to obtain a first frequency point and a second frequency point based on the modulation frequency and the neighborhood; and to obtain a fine frequency sweep range based on the first frequency point and the second frequency point, and to perform fine frequency sweep within the fine frequency sweep range; The data processing module includes a first frequency point and a second frequency point calculation module, a judgment module, and a distance to be measured calculation module; wherein, the first frequency point and the second frequency point calculation module is used to calculate the difference between the second frequency point and the first frequency point; taking the first frequency point and the second frequency point as the starting point respectively, and taking half of the difference as the step, the voltage value corresponding to the modulation frequency at different acquisition points is collected. Based on the voltage value at the sampling point and the modulation frequency, the slope of the straight line between the sampling point and the adjacent point is calculated. When the first frequency point is taken as the starting point and the slope of the straight line between the sampling point and the adjacent point changes from negative to positive, the process returns to the first frequency point and starts forward sampling calculation with half of the current step. When the second frequency point is taken as the starting point and the slope of the straight line between the sampling point and the adjacent point changes from positive to negative, the process returns to the second frequency point and starts reverse sampling calculation with half of the current step. The judgment module is used to determine whether the difference between the second frequency point and the first frequency point is less than a preset threshold; if yes, the acquisition stops; if no, bidirectional acquisition and calculation continue. The distance to be measured calculation module is used to calculate the distance to be measured based on the in-phase frequency.

7. An electronic device, characterized in that, include: At least one processor; The processor includes a memory communicatively connected to the at least one processor, wherein the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the polarization modulation fast ranging method as described in any one of claims 1 to 5.

8. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the polarization modulation fast ranging method according to any one of claims 1 to 5.

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