Miniaturized laser interferometer real-time ranging device and method based on point-by-point calculation

Abstract

The application discloses a kind of miniaturized laser interferometer real-time ranging device and method based on point-by-point calculation, its device includes light source, interference optical path, photoelectric detector, high-speed acquisition card.Interference optical path uses half-inch small size optical element, and the detection end adopts millimeter level photoelectric response surface compact dense row, and the overall device volume is small and light.First, interference signal is received by photoelectric detector;Subsequently converted into electrical signal, a series of interference signals obtained by high-speed acquisition card are point-by-point differential processing, and the phase of each sampling point is solved;The phase difference of two sampling points is demodulated to obtain the displacement difference of adjacent sampling points;Finally, the displacement of each sampling point is accumulated and output in real time, to realize nanometer level precision displacement measurement.To solve the problem of too long calculation time caused by point-by-point calculation, acquisition and calculation are processed simultaneously, and only simple operations such as addition and subtraction are used, and the calculation process is simple and efficient.The device structure is compact, and the displacement restoration method is high-speed and accurate.

Description

Technical Field

[0001] This invention belongs to the field of optical detection, specifically relating to a miniaturized laser interferometer real-time ranging device and method based on point-by-point calculation. Background Technology

[0002] Laser interferometric ranging is a high-precision distance measurement technique based on the interference phenomenon of light. The basic principle of laser interferometric ranging is the interference phenomenon produced by the overlapping of two light waves with a fixed phase difference, the same frequency, and the same direction of vibration. When the optical path difference between these two light waves changes, their interference fringes also change accordingly, thus reflecting the displacement information of the measured object. Laser interferometric ranging uses the laser wavelength as a reference and has very high measurement accuracy. Furthermore, laser interferometric ranging employs a non-contact measurement method, avoiding the errors and damage that may be caused by traditional contact measurements. This non-contact measurement method not only improves measurement accuracy but is also suitable for situations where direct contact measurement is not possible.

[0003] However, laser interferometric ranging requires the simultaneous installation of a reference mirror and a test mirror, thus demanding a relatively large installation space. This limits its application in certain compact or confined spaces to some extent. Laser interferometric ranging is highly sensitive to disturbances, such as vibrations caused by changes in cutting force, which can affect its measurement accuracy. Therefore, special care must be taken to avoid or minimize disturbances during use.

[0004] In his article "Research on Signal Processing and Measurement Error Compensation Method of Semiconductor Single-Frequency Laser Interferometer", Xie Bo used a 635nm semiconductor single-frequency laser for ranging. However, he did not consider the impact of the unstable wavelength of the conductor laser on the accuracy of the interference displacement. In addition, the overall ranging device was large in size and had limited applicability.

[0005] Traditional phase demodulation involves unwrapping operations, which are computationally complex, computationally intensive, and slow. Summary of the Invention

[0006] This invention proposes a miniaturized laser interferometer real-time ranging device and method based on point-by-point calculation, which solves the problems of miniaturization and portability of laser interferometers and high-precision real-time ranging. At the same time, it only relies on simple operations such as addition and subtraction, and the calculation process is concise and efficient, thus improving the calculation speed.

[0007] The technical solution for realizing this invention is as follows: a miniaturized laser interferometer real-time ranging device based on point-by-point calculation, comprising a frequency-stabilized HeNe laser, an interference optical path, a high-speed single-point photodetector, and a high-speed signal acquisition card; frequency-stable linearly polarized light emitted by the frequency-stabilized HeNe laser is incident on the interference optical path, and after passing through the interference optical path, four interference linearly polarized lights are formed. The four interference linearly polarized lights are respectively received by four high-speed single-point photodetectors to obtain four interference signals; the four high-speed single-point photodetectors are respectively connected to the high-speed signal acquisition card, and the high-speed signal acquisition card transmits the four interference signals to a computer for processing.

[0008] A real-time ranging method using a miniaturized laser interferometer based on point-by-point calculation, employing the aforementioned device, comprises the following steps:

[0009] Step 1: The four pairs of light emitted from the interference optical path interfere with each other; the third transmitted light is received by the first photodetector to obtain the first interference signal I1; the third reflected light is received by the second photodetector to obtain the second interference signal I2; the second transmitted light is received by the third photodetector to obtain the third interference signal I3; the second reflected light is received by the fourth photodetector to obtain the fourth interference signal I4; thus, four interference signals with a phase difference of 90° are obtained.

[0010] Step 2: Use a four-channel high-speed acquisition card to acquire the four interference signals in real time and send them to the computer.

[0011] Step 3: The computer performs differential calculations on the signals from each acquisition point to obtain the two orthogonal interference signals I at the first moment. sin_1 and I cos_1 And the two orthogonal interference signals I at the second moment sin_2 and I cos_2 .

[0012] Step 4: At this point, there is a slight phase shift between the two orthogonal signals. A slight phase shift elimination method is used to correct the two orthogonal signals.

[0013] By performing an arctangent operation on the two orthogonal interference signals at the first moment, the phase difference Δφ1 between the reference optical path and the moving optical path at the first moment can be obtained; by performing an arctangent operation on the two orthogonal interference signals at the second moment, the phase difference Δφ2 between the reference optical path and the moving optical path at the second moment can be obtained.

[0014] Step 5: Use phase difference information to restore displacement.

[0015] Compared with the prior art, the significant advantages of this invention are:

[0016] (1) Compared with other interferometers, the ranging device proposed in this invention is small in size (the size of the entire mounting plate is less than 120mm×100mm×40mm), convenient and portable, and suitable for various measurement environments.

[0017] (2) Taking advantage of the advantages of single-point high-speed photoelectric detector and high-speed acquisition card, a point-by-point calculation method is proposed, which can realize high-speed and high-precision real-time ranging. Attached Figure Description

[0018] Figure 1 This is a flowchart of the real-time ranging method of the present invention.

[0019] Figure 2 This is the interferometric optical path diagram for ranging according to the present invention. Detailed Implementation

[0020] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0021] This invention addresses the drawback of large structural volume in laser interferometric ranging devices by proposing for the first time a miniaturized real-time ranging device and method based on point-by-point calculation using a laser interferometer. It is suitable for field applications and mobile measurement tasks requiring high-precision measurement that can operate efficiently in confined spaces, effectively reducing the size of the device and achieving high-precision real-time ranging.

[0022] Combination Figure 1 and Figure 2 A miniaturized laser interferometer real-time ranging device based on point-by-point calculation includes a frequency-stabilized HeNe laser, an interference optical path, a high-speed single-point photodetector, and a high-speed signal acquisition card. Frequency-stable linearly polarized light emitted from the frequency-stabilized HeNe laser is incident on the interference optical path, forming four interferometric linearly polarized beams. These four beams are received by four high-speed single-point photodetectors, resulting in four interference signals. The four high-speed single-point photodetectors are connected to the high-speed signal acquisition card, which transmits the four interference signals to a computer for processing.

[0023] The interference optical path includes a first polarizing beam splitter 1, a first quarter-wave plate 2, a reference cornerstone prism 3, a second quarter-wave plate 4, a moving cornerstone prism 5, a non-polarizing beam splitter 6, a third quarter-wave plate 7, a second polarizing beam splitter 8, a first half-wave plate 9, and a third polarizing beam splitter 10.

[0024] The first optical path is arranged in sequence as follows: reference corner cube prism 3, first quarter-wave plate 2, first polarizing beam splitter 1, unpolarizing beam splitter 6, first half-wave plate 9, third polarizing beam splitter 10, and first photodetector 11.

[0025] The second optical path is arranged in sequence with the first polarizing beam splitter 1, the second quarter-wave plate 4, and the moving corner cone prism 5.

[0026] The second optical path is arranged in sequence with an unpolarized beam splitter 6, a third quarter-wave plate 7, a second polarized beam splitter 8, and a third photodetector 13.

[0027] The second photodetector 12 is located in the reflected light path of the third polarizing beam splitter 10, and the fourth photodetector 14 is located in the reflected light path of the second polarizing beam splitter 8.

[0028] The first optical path is perpendicular to the second and third optical paths;

[0029] The second and third optical paths are parallel;

[0030] In the interference optical path, the linearly polarized light emitted by the frequency-stabilized HeNe laser and collimated by the fiber collimator is incident on the first polarization beam splitter 1. The beam is reflected and transmitted at the splitting surface of the first polarization beam splitter 1 and split into two beams of S-polarized light and P-polarized light with mutually perpendicular polarization directions.

[0031] The S-polarized light reflected by the first polarizing beam splitter 1 is incident on the first quarter-wave plate 2. After passing through the first quarter-wave plate 2, the linearly polarized light becomes circularly polarized light and is incident on the reference corner cube prism 3. The light reflected by the reference corner cube prism 3 passes through the first quarter-wave plate 2 again and becomes linearly polarized light again before being incident on the first polarizing beam splitter 1.

[0032] P-polarized light transmitted through the first polarizing beam splitter 1 is incident on the second quarter-wave plate 4. After passing through the second quarter-wave plate 4, the linearly polarized light becomes circularly polarized light and is incident on the moving corner cube prism 5. The light reflected by the moving corner cube prism 5 passes through the second quarter-wave plate 4 again and becomes linearly polarized light again before being incident on the first polarizing beam splitter 1.

[0033] At this point, the polarization directions of the two linearly polarized beams have changed by 90°, but the polarization directions are still perpendicular to each other.

[0034] Two linearly polarized beams with mutually perpendicular polarization directions emitted from the first polarizing beam splitter 1 are reflected and transmitted at the beam splitting surface of the unpolarizing beam splitter 6, resulting in a first reflected beam and a first transmitted beam.

[0035] After the first reflected light passes through the third quarter-wave plate 7, its polarization direction changes, transforming from two linearly polarized beams with mutually perpendicular polarization directions into two circularly polarized beams with opposite rotation directions and a 90° phase delay. After these two circularly polarized beams are transmitted and reflected at the beam-splitting surface of the second polarizing beam splitter 8, they become the second transmitted light and the second reflected light. The second transmitted light and the second reflected light are two pairs of linearly polarized light, and each pair of linearly polarized light interferes with each other.

[0036] After the first transmitted light passes through the first half-wave plate 9, its polarization direction changes, transforming from two linearly polarized beams with mutually perpendicular polarization directions into two circularly polarized beams with opposite rotation directions and a phase delay of 180°. These two circularly polarized beams are transmitted and reflected at the beam-splitting surface of the third polarizing beam-splitting prism 10, resulting in a third transmitted light and a third reflected light. The third transmitted light and the third reflected light are two pairs of linearly polarized light, and each pair of linearly polarized light interferes. The four pairs of linearly polarized light emitted from the interference path also interfere with each other.

[0037] Four pairs of linearly polarized light are received by the first photodetector 11, the second photodetector 12, the first photodetector 13, and the fourth photodetector 14, respectively, to obtain four interference signals with phase differences of 90°.

[0038] The aforementioned interference optical path structure is compact, with small component size, and can be integrated onto a small-sized mounting plate. The entire mounting plate is less than 120mm × 100mm × 40mm in size.

[0039] The frequency-stabilized HeNe laser outputs linearly polarized light with a stable frequency and wavelength fluctuation of less than 2 pm.

[0040] The high-speed single-point photodetector has a bandwidth of 10MHz and a rise time of <11ns; the high-speed signal acquisition card is a four-channel acquisition card with a maximum sampling rate of 2MS / s per channel, meaning each channel can acquire 2×10⁻⁶ samples per second. 6 The signal from each sampling point.

[0041] A real-time ranging method using a miniaturized laser interferometer based on point-by-point calculation, comprising the following steps:

[0042] Step 1: The four pairs of light emitted from the interference optical path interfere with each other; the third transmitted light is received by the first photodetector 11 to obtain the first interference signal I1; the third reflected light is received by the second photodetector 12 to obtain the second interference signal I2; the second transmitted light is received by the third photodetector 13 to obtain the third interference signal I3; the second reflected light is received by the fourth photodetector 14 to obtain the fourth interference signal I4; thus, four interference signals with a phase difference of 90° are obtained.

[0043] Step 2: Use a four-channel high-speed acquisition card to acquire the four interference signals in real time and send them to the computer;

[0044] Step 3: The computer performs differential calculations on the signal from each acquisition point, as follows:

[0045] Differential processing is performed on the four interference signals acquired in real time by the four-channel high-speed card at the first moment. Differential processing is performed between the first interference signal and the second interference signal acquired at the first moment, and between the third interference signal and the fourth interference signal acquired at the first moment, resulting in two orthogonal interference signals at the first moment:

[0046] I sin_1 =I 1_1 -I 2_1

[0047] I cos_1 =I 3_1 -I 4_1

[0048] Among them, I sin_1 For the sinusoidal signal at the first moment, I cos_1 For the cosine signal at the first moment, I 1_1 I is the interference signal received by the first photodetector 11 at the first moment. 2_1 I is the interference signal received by the second photodetector 12 at the first moment. 3_1 The interference signal received by the third photodetector 13 at the first moment, I 4_1 This is the interference signal received by the fourth photodetector 14 at the first moment.

[0049] Differential processing is performed between the first and second interference signals acquired at the second time point, and differential processing is performed between the third and fourth interference signals acquired at the second time point to obtain two orthogonal interference signals at the second time point:

[0050] I sin_2 =I 1_2 -I 2_2

[0051] I cos_2 =I 3_2 -I 4_2

[0052] Among them, I sin_2 For the sinusoidal signal at the second moment, I cos_2 For the cosine signal at the second time step, I 1_2 I is the interference signal received by the first photodetector 11 at the second moment. 2_2 I is the interference signal received by the second photodetector 12 at the second moment. 3_2 For the interference signal received by the third photodetector 13 at the second moment, I 4_2 This is the interference signal received by the fourth photodetector 14 at the second moment.

[0053] Step 4: At this point, there is a slight phase shift between the two orthogonal signals. A slight phase shift elimination method can be used to correct the two orthogonal signals to improve measurement accuracy, as detailed below:

[0054] Assume the amplitude of the cosine signal is K. cos The amplitude of the sinusoidal signal is K. sin The two orthogonal signals are:

[0055] I cos =K cos cosφ

[0056] I sin =K sin sin(φ+δ)

[0057] Among them, I cos For a cosine signal, I sin φ is a sinusoidal signal, φ is the phase, and δ is the small phase shift between the two orthogonal signals.

[0058] Introduce a quantity K sincos It corresponds to I sin +I cos The amplitude of the maximum value, i.e.:

[0059]

[0060] Therefore, we can conclude that:

[0061]

[0062] This allows us to calculate the minute phase shift δ, thereby eliminating the minute phase shift δ between orthogonal signals, i.e.:

[0063] I cos =K cos cosφ=I′ cos

[0064]

[0065] Among them, I′ cos For the corrected cosine signal, I′ sin The corrected sine signal, i.e.

[0066] I' cos =I cos

[0067]

[0068] Using the above correction method, we can obtain the corrected orthogonal signals:

[0069] I' sin_1 =sin(φ)2_1 -φ 1_1 )

[0070] I' cos_1 =cos(φ 2_1 -φ 1_1 )

[0071] I' sin_2 =sin(φ) 2_2 -φ 1_2 )

[0072] I' cos_2 =cos(φ 2_2 -φ 1_2 )

[0073] Where, φ 1_1 For the phase of the reference optical path at the first moment, φ 2_1 φ represents the phase of the moving optical path at the first moment. 2_1 -φ 1_1 The phase difference between the reference optical path and the moving optical path is also denoted as Δφ1; φ 1_2 The phase of the reference optical path at the second moment, φ 2_2 φ represents the phase of the moving optical path at the second moment. 2_2 -φ 1_2 The phase difference between the reference optical path and the moving optical path at the second moment can also be denoted as Δφ2.

[0074] By performing an arctangent operation on the two orthogonal interference signals at the first moment, the phase difference Δφ1 between the reference optical path and the moving optical path at the first moment can be obtained; by performing an arctangent operation on the two orthogonal interference signals at the second moment, the phase difference Δφ2 between the reference optical path and the moving optical path at the second moment can be obtained.

[0075] Step 5: Use the phase difference information to restore the displacement, as follows:

[0076] The phase difference information between two adjacent sampling points is obtained, and the phase difference at the second time point is subtracted from the phase difference at the first time point, i.e.:

[0077] Δφ2-Δφ1=φ 2_2 -φ 1_2 -φ 2_1 +φ 1_1

[0078] Since the reference cone prism 3 does not move, the reference path phase information remains unchanged, that is:

[0079] Δφ2-Δφ1=φ 2_2 -φ 2_1

[0080] The phase difference information of the moving optical path between two adjacent sampling points is thus obtained and denoted as ΔΦ1;

[0081] Based on the relationship between phase difference and displacement, the distance the moving cone moves relative to the reference cone at the first and second moments can be obtained, which is the displacement Δx1 of the moving cone between the first and second moments.

[0082]

[0083] Where λ is the wavelength of the HeNe laser;

[0084] By continuously calculating the phase difference between two adjacent sampling points, the displacement between two adjacent sampling points can be obtained. By summing the displacements between all adjacent sampling points, the total displacement x of the moving cone can be obtained.

[0085]

[0086] Where, Δx i Let φ be the displacement between time i+1 and time i. 2_i+1 Let φ be the phase of the moving optical path at time i+1. 2_i Let n be the phase of the moving optical path at time i, and n represent the total number of sampling points.

[0087] Example 1: Application of miniaturized laser interferometer in high-speed dynamic measurement

[0088] In some applications, the objects being measured are often high-speed moving objects, such as in mechanical engineering, aerospace, and automated production lines. Traditional laser interferometers are prone to measurement errors or data delays when handling high-speed dynamic measurements due to frequent signal changes or the high speed of the target. Therefore, it is necessary to maintain high-precision measurements under high-speed dynamic conditions.

[0089] Device configuration: The device is consistent with the aforementioned claims, wherein the motion angle cone prism 5 is connected to the object being measured to maintain a consistent motion state.

[0090] ① The motion cone prism 5 is connected to the object being measured to maintain a consistent motion state.

[0091] ②When the object being measured begins to move, the motion angle cone prism 5 also begins to move simultaneously.

[0092] ③ Due to the motion of the moving corner cube prism 5, the four interference signals generated are received in real time by the first photodetector 11, the second photodetector 12, the first photodetector 13, and the fourth photodetector 14. The high-speed signal acquisition card transmits the four interference signals to the computer for processing.

[0093] ④ The computer performs point-by-point differential calculation, orthogonal signal correction, and displacement restoration on the signal using a real-time ranging method based on a miniaturized laser interferometer with point-by-point calculation.

[0094] ⑤ Finally, the computer outputs the displacement information of the measured object in real time based on the calculation results.

Claims

1. A real-time ranging method for a miniaturized laser interferometer based on point-by-point calculation, characterized in that, A miniaturized laser interferometer real-time ranging device is provided, comprising a frequency-stabilized HeNe laser, an interference optical path, a high-speed single-point photodetector, and a high-speed signal acquisition card. Frequency-stabilized linearly polarized light emitted from the frequency-stabilized HeNe laser is incident on the interference optical path, forming four interferometric linearly polarized beams. These four beams are received by four high-speed single-point photodetectors, yielding four interference signals. Each of the four high-speed single-point photodetectors is connected to the high-speed signal acquisition card, which transmits the four interference signals to a computer for processing. The interference optical path includes a first polarizing beam splitter (1), a first quarter-wave plate (2), a reference corner cube prism (3), a second quarter-wave plate (4), a moving corner cube prism (5), a non-polarizing beam splitter (6), a third quarter-wave plate (7), a second polarizing beam splitter (8), a first half-wave plate (9), and a third polarizing beam splitter (10). In the interference optical path, the linearly polarized light emitted by the frequency-stabilized HeNe laser and collimated by the fiber collimator is incident on the first polarization beam splitter (1). The beam is reflected and transmitted at the splitting surface of the first polarization beam splitter (1) and split into two beams of S-polarized light and P-polarized light with mutually perpendicular polarization directions. S-polarized light reflected by the first polarizing beam splitter (1) is incident on the first quarter-wave plate (2). After passing through the first quarter-wave plate (2), the linearly polarized light becomes circularly polarized light and is incident on the reference corner cube prism (3). The light reflected by the reference corner cube prism (3) passes through the first quarter-wave plate (2) again and becomes linearly polarized light again before being incident on the first polarizing beam splitter (1). P-polarized light transmitted through the first polarizing beam splitter (1) is incident on the second quarter-wave plate (4). After passing through the second quarter-wave plate (4), the linearly polarized light becomes circularly polarized light and is incident on the moving corner pyramid prism (5). The light reflected by the moving corner pyramid prism (5) passes through the second quarter-wave plate (4) again and becomes linearly polarized light again before being incident on the first polarizing beam splitter (1). At this point, the polarization directions of the two linearly polarized beams have changed by 90°, but the polarization directions are still perpendicular to each other. Two linearly polarized beams with mutually perpendicular polarization directions emitted from the first polarizing beam splitter (1) are reflected and transmitted at the beam splitting surface of the unpolarizing beam splitter (6) to obtain the first reflected light and the first transmitted light. After the first reflected light passes through the third quarter-wave plate (7), the polarization direction changes, and the two linearly polarized lights with mutually perpendicular polarization directions become two circularly polarized lights with opposite rotation directions and a 90° phase delay. After these two circularly polarized lights are transmitted and reflected at the beam-splitting surface of the second polarizing beam splitter (8), the second transmitted light and the second reflected light are obtained. The second transmitted light and the second reflected light are two pairs of linearly polarized lights, and each pair of linearly polarized lights interferes with each other. After the first transmitted light passes through the first half-wave plate (9), the polarization direction changes, and the two linearly polarized beams with mutually perpendicular polarization directions become two circularly polarized beams with opposite rotation directions and a phase delay of 180°. After these two circularly polarized beams are transmitted and reflected at the beam-splitting surface of the third polarizing beam splitter (10), the third transmitted light and the third reflected light are obtained. The third transmitted light and the third reflected light are two pairs of linearly polarized light, and each pair of linearly polarized light interferes with each other. The four pairs of light emitted from the interference optical path interfere with each other; the third transmitted light is received by the first photodetector (11), the third reflected light is received by the second photodetector (12), the second transmitted light is received by the third photodetector (13), and the second reflected light is received by the fourth photodetector (14), thus obtaining four interference signals with a phase difference of 90° in sequence. The steps are as follows: Step 1: The four pairs of light emitted from the interference optical path interfere with each other; the third transmitted light is received by the first photodetector (11) to obtain the first interference signal. The third reflected light is received by the second photodetector (12), resulting in the second interference signal. ; The second transmitted light is received by the third photodetector (13), resulting in a third interference signal. The second reflected light is received by the fourth photodetector (14), resulting in the fourth interference signal. This yields four interference signals with phases differing by 90° sequentially. Step 2: Use a four-channel high-speed acquisition card to acquire the four interference signals in real time and send them to the computer; Step 3: The computer performs differential calculations on the signals from each acquisition point to obtain the two orthogonal interference signals at the first moment. and And the two orthogonal interference signals at the second moment. and ; Differential processing is performed on the four interference signals acquired in real time by the four-channel high-speed card at the first moment. Differential processing is performed between the first interference signal and the second interference signal acquired at the first moment, and between the third interference signal and the fourth interference signal acquired at the first moment, resulting in two orthogonal interference signals at the first moment: ， ， in, The first moment is the sinusoidal signal. The cosine signal at the first moment. The interference signal received by the first photodetector (11) at the first moment. The interference signal received by the second photodetector (12) at the first moment. The interference signal received by the third photodetector (13) at the first moment. The interference signal received by the fourth photodetector (14) at the first moment; Differential processing is performed between the first and second interference signals acquired at the second time point, and differential processing is performed between the third and fourth interference signals acquired at the second time point to obtain two orthogonal interference signals at the second time point: ， ， in, The signal is a sinusoidal signal at the second moment. This is the cosine signal at the second moment. The interference signal received by the first photodetector (11) at the second moment. The interference signal received by the second photodetector (12) at the second moment. The interference signal received by the third photodetector (13) at the second moment. The interference signal received by the fourth photodetector (14) at the second moment; Step 4: At this point, there is a slight phase shift between the two orthogonal signals. A slight phase shift elimination method is used to correct the two orthogonal signals. By performing arctangent calculation on the two orthogonal interference signals at the first moment, the phase difference between the reference optical path and the moving optical path at the first moment can be obtained. By performing arctangent calculation on the two orthogonal interference signals at the second moment, the phase difference between the reference optical path and the moving optical path at the second moment can be obtained. ; Assume the amplitude of the cosine signal is The amplitude of the sinusoidal signal is The two orthogonal signals are: ， in, For cosine signals, It is a sinusoidal signal. For phase, This represents the tiny phase shift that exists between two orthogonal signals; Introduce a quantity It corresponds to The amplitude of the maximum value, i.e.: ； Therefore, we can conclude that: ， This allows us to calculate minute phase shifts. This eliminates the tiny phase shift between orthogonal signals. ,Right now: ， in, For the corrected cosine signal, The corrected sine signal, i.e. ， Using the above correction method, the corrected orthogonal signals are obtained. : ， ， ， ， in, The phase of the reference optical path at the first moment, The phase of the moving light path at the first moment. The phase difference between the reference optical path and the moving optical path is also denoted as... ; The phase of the reference optical path at the second moment. The phase of the moving light path at the second moment. The phase difference between the reference optical path and the moving optical path at the second moment is also denoted as... ; By performing arctangent calculation on the two orthogonal interference signals at the first moment, the phase difference between the reference optical path and the moving optical path at the first moment can be obtained. By performing arctangent calculation on the two orthogonal interference signals at the second moment, the phase difference between the reference optical path and the moving optical path at the second moment can be obtained. ; Step 5: Use phase difference information to restore displacement.

2. The real-time ranging method for a miniaturized laser interferometer based on point-by-point calculation according to claim 1, characterized in that, In step 5, the displacement is restored using the phase difference information, as detailed below: The phase difference information between two adjacent sampling points is obtained, and the phase difference at the second time point is subtracted from the phase difference at the first time point, i.e.: ， Since the reference cone prism (3) does not move, the reference path phase information remains unchanged, i.e.: ， This yields the phase difference information of the moving optical path between two adjacent sampling points, denoted as: ; Based on the relationship between phase difference and displacement, the distance the moving cone moves relative to the reference cone at the first and second moments can be derived; that is, the displacement of the moving cone between the first and second moments. ,Right now: ， in, The wavelength of the HeNe laser; By continuously calculating the phase difference between two adjacent sampling points, the displacement between two adjacent sampling points can be obtained. By summing the displacements between all adjacent sampling points, the total displacement x of the moving cone can be obtained. ， in, For the first Time and the Displacement between moments For the first The phase of the constantly moving optical path, For the first The phase of the moving optical path at any given moment, where n represents the total number of sampling points.

3. The real-time ranging method for a miniaturized laser interferometer based on point-by-point calculation according to claim 1, characterized in that, The interference optical path structure is compact and integrated on the mounting plate, with the entire mounting plate measuring less than 120mm × 100mm × 40mm.

4. The real-time ranging method for a miniaturized laser interferometer based on point-by-point calculation according to claim 1, characterized in that, The frequency-stabilized HeNe laser outputs linearly polarized light with a stable frequency and wavelength fluctuation of less than 2 pm.

5. The real-time ranging method for a miniaturized laser interferometer based on point-by-point calculation according to claim 1, characterized in that, The high-speed single-point photodetector has a bandwidth of 10MHz and a rise time of <11ns; the high-speed signal acquisition card is a four-channel acquisition card, with a maximum sampling rate of 2MS / s per channel, meaning that each channel can acquire data per second. The signal from each sampling point.

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