Multistage cascade type large-angle light beam deflection control system based on optical phased array

Abstract

The invention relates to the technical field of optical phased arrays, in particular to a multistage cascade type large-angle light beam deflection control system based on an optical phased array. The device comprises a region phase unit, an angle division unit and a compensation synthesis unit. The compensation synthesis unit calculates the index corresponding to the coarse adjustment angle and the fine angle phase interpolation according to the angle coordinate, calculates the compensation phase according to the first lookup table and the fine angle phase interpolation, and performs phase synthesis by using the phase difference needing to be adjusted in the monitoring angle direction and combining the compensation phase. The coarse tuning OPA device breaks through the limitation of the maximum deflection angle of the single-stage OPA by calculating the index and angle residual error corresponding to the coarse tuning angle, so that the scanning range of the light beam is expanded, the detection coverage area is increased, the detection blind area is reduced, meanwhile, fine angle phase interpolation is carried out in combination with a second lookup table, and the detection accuracy is improved. Therefore, the light beam can more accurately point to the target area, and the detection precision is improved.

Description

Technical Field

[0001] This invention relates to the field of optical phased array technology, and more specifically, to a multi-stage cascaded large-angle beam deflection control system based on an optical phased array. Background Technology

[0002] Multi-stage cascaded large-angle beam deflection control of optical phased arrays is an advanced optical control technology system. An optical phased array is an array composed of multiple optical units whose phases can be controlled independently. By precisely adjusting the phase of each unit, the wavefront of the beam is changed using the principle of light wave interference, thereby changing the direction of beam propagation. The multi-stage cascaded structure connects multiple such optical phased array modules in a certain order. Each module further deflects the beam based on the previous stage, thereby breaking through the limitation of the deflection angle of a single optical phased array and achieving precise and rapid beam deflection over a wider range. However, existing multi-stage cascaded large-angle beam deflection control of optical phased arrays suffers from limitations in maximum deflection angle and inability to meet the requirements of large field of view. Due to the limitation of the maximum deflection angle, the detection coverage of existing multi-stage cascaded large-angle beam deflection control optical phased arrays cannot meet the needs of some application scenarios that require a large field of view, such as earthquake monitoring and long-distance target detection, where it is necessary to monitor and detect a large spatial area, but existing multi-stage cascaded systems cannot provide a sufficiently large field of view, thus creating detection blind spots. Therefore, existing single-stage optical phased array (OPA) beam deflection technology has many limitations in practical applications. Due to the influence of diffraction limit, its maximum deflection angle is usually ≤30°. This angle limitation results in a very narrow detection coverage of existing single-stage optical phased array (OPA) beam deflection technology, which is difficult to meet the requirements of large field of view in long-distance detection. In actual earthquake monitoring scenarios, the narrow detection coverage makes many areas unable to be effectively detected, which easily leads to detection blind spots. Once earthquake-related minor changes occur in these blind spots, they cannot be detected in time, thus affecting the accuracy and timeliness of earthquake early warning. In addition, single-stage OPA devices also have shortcomings in terms of accuracy. Due to their limited angle adjustment range, it is difficult to finely control the beam direction and accurately point it at the target detection area. When sensing changes in underground rock stress and small displacements in the crust, high-precision detection methods are required to capture these weak signals. However, the limitations of single-stage OPA devices make it impossible to meet this requirement, reducing the accuracy and reliability of the detection. Therefore, we provide a multi-stage cascaded large-angle beam deflection control system based on optical phased array. Summary of the Invention

[0003] The purpose of this invention is to provide a multi-stage cascaded large-angle beam deflection control system based on an optical phased array to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides a multi-stage cascaded large-angle beam deflection control system based on an optical phased array, including a region phase unit, an angle division unit, and a compensation synthesis unit; The region phase unit is configured to acquire the scanning angle coordinates of the target region and calculate the phase difference that needs to be adjusted in the direction of the scanning angle coordinates; The angle division unit is communicatively connected to the region phase unit and is configured to calibrate the first-level coarse-tuning optical phased array and the second-level fine-tuning optical phased array based on the scanning angle coordinates and phase difference, and generate a first lookup table corresponding to the first-level coarse-tuning optical phased array and a second lookup table corresponding to the second-level fine-tuning optical phased array. The compensation synthesis unit, communicatively connected to the region phase unit and the angle division unit, is configured to query the first lookup table to obtain a first-level coarse adjustment index and an angle residual based on the current target scanning angle coordinates, and to query the second lookup table based on the angle residual to obtain a fine angle phase interpolation. The compensation synthesis unit is also configured to combine the phase difference, the phase value corresponding to the first-level coarse adjustment index, and the fine angle phase interpolation to perform temperature compensation and phase synthesis, generating and outputting a synthesized phase signal for driving the first-level coarse adjustment optical phased array and the second-level fine adjustment optical phased array.

[0005] As a further improvement to this technical solution, the regional phase unit includes a coordinate transformation module and a regional angle module; The coordinate transformation module acquires the WGS-84 coordinate system of stations A and B, and obtains the coordinates of stations A and B from the WGS-84 coordinate system; Obtain the longitude and latitude of station A to derive the rotation matrix around the z-axis and the rotation matrix around the y-axis. Combine the rotation matrix around the z-axis and the rotation matrix around the y-axis, first perform the rotation around the y-axis, and then perform the rotation around the z-axis to obtain the complete rotation matrix from the WGS-84 coordinate system to the NED coordinate system. The coordinates of station A in the WGS-84 coordinate system are converted to coordinates in the NED coordinate system using the complete rotation matrix and the coordinates of station A in the WGS-84 coordinate system. The region angle module is used to receive the rotation matrix, A-site coordinates and B-site coordinates from the coordinate transformation module, and to calculate the reference vector and the components of the reference vector in the WGS-84 coordinate system, respectively. Based on the components of the reference vector in the WGS-84 coordinate system, the components of the reference vector in the NED coordinate system are calculated using the rotation matrix. The detection area is determined by the components of the reference vector in the NED coordinate system, thus obtaining the range of the detection area.

[0006] As a further improvement to this technical solution, the region angle module also includes the following steps: The detection area is divided into grids into multiple small units, and the number of units in the horizontal and vertical directions of the detection area is recorded. Each small unit within the detection area corresponds to a grid point, and each grid point corresponds to an angular coordinate. The angular coordinates are calculated based on the scope of the detection area and the number of units divided in the horizontal and vertical directions.

[0007] As a further improvement to this technical solution, the regional phase unit also includes a phase difference module; The phase difference module receives the angular coordinates from the area angle module and uses the angular coordinates to determine different monitoring directions. The phase in the monitoring direction is measured using a detector to obtain... The error in the monitoring angle direction is calculated by measuring the phase at a given moment; Historical data is extracted from the database, and then proportional, integral, and differential coefficients are extracted from the historical data. Combined with the error calculation, the phase difference that needs to be adjusted in the monitoring angle direction is calculated. The light intensity distribution in the first to fourth quadrant regions is obtained by a four-quadrant detector, and then double integration is performed to obtain the double integral from the first to the fourth quadrant. The zero-position voltage reference is calculated by combining the photoelectric conversion coefficient in historical data.

[0008] As a further improvement to this technical solution, the angle division unit includes an angle judgment module and a division generation module; The angle determination module is used to receive the zero-position voltage reference in the phase difference module, the monitoring angle direction, and the detection area in the regional angle module; A primary coarse-tuning OPA device with 256 elements and a secondary fine-tuning OPA device with 2048 elements were set up in the detection area, and the spacing between the elements in the primary coarse-tuning and secondary fine-tuning OPA devices was recorded. The monitoring angle direction includes multiple angles. An angle is randomly selected from the monitoring angle direction, and the phase value of the 256 array elements is calculated in combination with the spacing between the array elements in the 256 array element OPA1 device. The phase value is applied to the first-level coarse-tuning OPA device, so that the array elements modulate the phase of the passing light wave according to the phase value; The actual voltage in the monitoring angle direction is collected by a voltage sensor, and the voltage change is calculated by combining it with the zero-position voltage reference. Extract the scaling factor from historical data, combine it with voltage change to convert voltage data into actual angle, and collect the range of actual angle. The division generation module is used to receive the first lookup table in the angle judgment module, the range of actual angles, and the spacing between array elements in the secondary fine-tuning OPA device, and to obtain adjacent actual angles from the first lookup table to calculate the difference of actual angles; The range of actual angles is divided according to the difference in actual angles. Each sub-interval corresponds to a difference in an actual angle; The actual angle is determined based on the difference between the actual angles of the sub-intervals. The range of values ​​for is the range of values ​​for the subinterval.

[0009] As a further improvement to this technical solution, the angle determination module also includes the following steps: The original light intensity value at the acquisition angle is combined with the maximum light intensity value in historical data and the spacing between array elements in the first-level coarse-tuning OPA device and the monitoring angle direction to normalize the light intensity and obtain the normalized light intensity value. The angle and the corresponding original light intensity value are combined into a data pair and defined as a data point in the data space. The normalized light intensity value is used to determine whether the data point is a valid point. Once a data point is determined to be a valid point, the number of valid points is recorded, and a first lookup table is generated by combining the angle, the actual angle, and the phase value of the 256 array elements.

[0010] As a further improvement to this technical solution, the partitioning generation module also includes the following steps: The phase value of the 2048 array elements is calculated based on the actual angle and the spacing between the array elements in the secondary fine-tuning OPA device, and the phase value of the 2048 array elements is applied to the secondary fine-tuning OPA device. A four-quadrant detector is used to collect actual light intensity distribution data, receive light intensity value signals corresponding to different actual angles, and process the light intensity value signals to obtain the actual measured light intensity distribution. Divide the range of values ​​of the sub-interval into 50 small angular intervals, record the division position and the corresponding angle value, and regard the angle value corresponding to the division position as the calibration point. The specific angle of the calibration point is measured using a cross-correlation algorithm based on the actual measured light intensity distribution and a reference pattern from historical data. From a practical perspective The specific angles of the calibration points and the phase values ​​of the 2048 array elements are used to generate a second lookup table.

[0011] As a further improvement to this technical solution, the compensation synthesis unit is used to receive the angle coordinates in the region angle module and the actual angle in the angle judgment module, and to receive the phase difference that needs to be adjusted in the monitoring angle direction in the second lookup table, the first lookup table and the phase difference module in the division generation module. Calculate the index corresponding to the coarse adjustment angle based on the angle coordinates and the actual angle, and then calculate the angle residual based on the angle coordinates and the actual angle. The fine angle phase interpolation is calculated using the spline interpolation function based on the index corresponding to the angle residual and the coarse adjustment angle, combined with the second lookup table. Retrieve the raw phase value corresponding to the specific index applied to the first-level coarse-tuning OPA device from the first lookup table. Combine the raw phase value with the temperature coefficient from historical data. The compensation phase, calculated from the reference temperature and after temperature compensation, is applied to the primary coarse-tuned OPA device. Then, through precise angular phase interpolation, combined with the temperature coefficient from historical data... The compensation phase, calculated with reference temperature and then applied to the secondary fine-tuning OPA device after temperature compensation, is then applied.

[0012] As a further improvement to this technical solution, the compensation synthesis unit further includes the following steps: By using the phase difference that needs to be adjusted in the monitoring angle direction, combined with the angle-phase correlation coefficient and angle residual in historical data, mode coupler compensation is performed to obtain the total phase value; The compensated phase and the total phase value are combined to output the combined phase, which is then sent to the OPA device to adjust the beam direction to the detection area.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. In this multi-stage cascaded large-angle beam deflection control system based on optical phased arrays, the compensation synthesis unit calculates the index and angle residual corresponding to the coarse adjustment angle based on the angle coordinates and the actual angle. It then calculates the fine angle phase interpolation using a second lookup table, calculates the compensation phase applied to the first-stage coarse adjustment OPA device after temperature compensation using a first lookup table, and calculates the compensation phase applied to the second-stage fine adjustment OPA device after temperature compensation using the fine angle phase interpolation. Utilizing the phase difference that needs adjustment in the monitored angle direction, it performs phase synthesis in conjunction with the compensation phase, outputs the synthesized phase, and sends it to the OPA device to adjust the beam direction towards the detection area. The coarse adjustment OPA device, by calculating the index and angle residual corresponding to the coarse adjustment angle and combining the lookup table to calculate the compensation phase, can achieve a large range of angle adjustments, breaking through the limitation of the maximum deflection angle of a single-stage OPA. This expands the beam scanning range, increases the detection coverage area, and reduces the detection blind zone. Simultaneously, by combining the second lookup table for fine angle phase interpolation, it can more precisely control the beam direction, enabling the beam to more accurately point towards the target area. This allows for precise sensing of underground rock stress changes and minute crustal displacements, improving detection accuracy.

[0014] 2. In this multi-stage cascaded large-angle beam deflection control system based on optical phased arrays, according to the actual angle... The phase value of 2048 array elements is calculated based on the spacing between array elements in the secondary fine-tuning OPA device. This phase value is then applied to the secondary fine-tuning OPA device. A four-quadrant detector is used to collect actual light intensity distribution data, receiving light intensity signals corresponding to different actual angles. These signals are processed to obtain the actual measured light intensity distribution. The value range of the sub-interval is evenly divided into 50 small angular intervals, and the division positions and corresponding angle values ​​are recorded. The angle values ​​corresponding to the division positions are considered calibration points. A cross-correlation algorithm is used to measure the specific angle of the calibration points based on the actual measured light intensity distribution and a reference pattern from historical data. The actual angle is then used to determine the calibration point's angle. The specific angle of the calibration point and the phase value of the 2048 array elements generate a second lookup table. Based on the phase control of multiple array elements, the beam can be accurately pointed within a larger angular range, thereby expanding the detection coverage area of ​​optical detection technology, reducing the detection blind zone caused by angle limitations, and meeting the "large field of view" requirement in long-distance detection. At the same time, the generation of the second lookup table can adapt to complex detection area environments and the high precision requirements of earthquake monitoring, enhancing the overall adaptability and stability in complex environments. Attached Figure Description

[0015] Figure 1 This is a block diagram of the module units of the present invention.

[0016] The meanings of the labels in the diagram are as follows: 1. Regional phase unit; 11. Coordinate transformation module; 12. Regional angle module; 13. Phase difference module; 2. Angle division unit; 21. Angle judgment module; 22. Division generation module; 3. Compensation synthesis unit. Detailed Implementation

[0017] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Example 1 This invention provides a multi-stage cascaded large-angle beam deflection control system based on an optical phased array. Please refer to [link / reference]. Figure 1 It includes regional phase unit 1, angle division unit 2 and compensation synthesis unit 3.

[0019] The regional phase unit 1 includes a coordinate transformation module 11 and a regional angle module 12; Due to the complex terrain of the Longmenshan fault zone, the monitoring profile needs to traverse the main fault zone. The two end stations (Site A (transmitter tower) and Site B (reflector array)) may not be directly visible due to mountains and valleys. The coordinate transformation module 11 establishes Site A and Site B at elevations of 1200m and 1100m respectively along the Longmenshan fault zone. Transmitter tower A and reflector array B are installed at each end station. GNSS equipment installed at Site A and Site B is used for 72 hours of observation. The GNSS equipment receives signals transmitted by multiple satellites, measures the propagation time of the signals from the satellites to the GNSS equipment, and calculates the distance between the GNSS equipment and each satellite, thus obtaining the WGS-84 coordinate system. The coordinates of Site A are then derived from the WGS-84 coordinate system. and B site coordinates Setting up stations at different altitudes helps the signals emitted by the towers to overcome the terrain obstacles in between and reach the reflective array, ensuring the effective transmission and reception of the equipment's monitoring signals, thereby enabling effective monitoring of the main fault zone, overcoming terrain obstacles, and reducing the obstruction of the line of sight by the surrounding terrain. The center of the optical platform at the top of station A is obtained and used as the origin. Station A is a physical building or structure located at an altitude of 1200m. The optical platform refers to a platform installed at the top of launch tower A, typically used to house optical equipment (such as telescopes, lidar, and optical sensors). The center refers to the geometric center of the optical platform; that is, on a plane, the distance from this center to all points on the edge of the optical platform is statistically equal. In three-dimensional space, it is the center of the optical platform's volume. The local plumb line direction is determined using a measuring instrument and used as the Z-axis. Due north is determined using a compass and used as the X-axis, and due east is determined as the Y-axis. Then, the longitude of station A is obtained. and latitude According to longitude Rotate the X and Y axes of the WGS-84 coordinate system to directions related to the meridian and equatorial plane where site A is located, and then derive the rotation matrix around the z-axis. The specific algorithm formula is as follows: The negative sign indicates that the rotation direction is opposite to the positive direction, and then based on the latitude... The coordinate system, after being rotated around the z-axis, is further rotated to align with the horizontal and vertical planes where station A is located, thus obtaining the rotation matrix around the y-axis. Specific algorithm formula: ;in, A way to convert latitude information into rotation angle; By combining the rotation matrices around the z-axis and y-axis, first performing the rotation around the y-axis and then the rotation around the z-axis, we obtain the complete rotation matrix from the WGS-84 coordinate system to the NED coordinate system. Using a complete rotation matrix and the coordinates of site A in the WGS-84 coordinate system, combined with the X, Y, and Z axes, the coordinates of site A in the WGS-84 coordinate system are converted to coordinates in the NED coordinate system. Specific algorithm formula: The coordinate transformation module 11 converts the coordinates of station A in the WGS-84 coordinate system to the coordinates in the NED coordinate system through a complete rotation matrix. This solves the problem that traditional methods rely on optical alignment or coarse measurement and cannot provide a reliable absolute coordinate origin for millimeter-level displacement inversion when there is no direct view or obstruction (such as mountains). It also lays the foundation for subsequent terrain control to no longer be a blind angle traversal. The region angle module 12 is used to receive the rotation matrix, coordinates of station A, and coordinates of station B from the coordinate transformation module 11, and calculate the reference vector based on the coordinates of station A and station B. Then, based on the coordinates of station A and station B, calculate the components of the reference vector in the WGS-84 coordinate system. Specific algorithm formula: Based on the components of the reference vector in the WGS-84 coordinate system, the components of the reference vector in the NED coordinate system are calculated using the rotation matrix. Specific algorithm formula: The exploration area of ​​the Longmenshan fault zone topography is determined by the components of the reference vector in the NED coordinate system. Since the geological activity of the Longmenshan fault zone topography may exhibit more significant characteristics within specific horizontal and vertical angular ranges, the horizontal 60° range may cover the main trend and active area of ​​the Longmenshan fault zone topography, and can capture stress changes and displacement information of the Longmenshan fault zone topography in this direction. The vertical 10° range may be related to the depth distribution of the Longmenshan fault zone topography and the layered structure of the rock layers. Within this zenith angle range, it may be easier to monitor geological activity signals deep underground. Therefore, the detection area is defined as horizontal 60° and vertical 10°. Once the exploration area of ​​the Longmenshan fault zone's topography is determined, the exploration area is monitored. First, the exploration area is divided into multiple 500m × 500m grids, and the number of horizontally divided units is recorded. and the number of units divided in the vertical direction Each small unit within the detection area corresponds to a grid point, and each grid point corresponds to an angular coordinate. The angular coordinates are calculated based on the scope of the detection area and the number of units divided in the horizontal and vertical directions. The specific process for calculating angular coordinates: ;in, Indicates the first An angle value in the x-direction; It is an integer index, with a value range from 0 to... , Used to select different angles in sequence; It is the starting angle of this angle sequence, that is, when hour, ; This refers to the angular interval between two adjacent angles, as... As the angle increases, the angle value increases at this interval; for example, when When it changes from 0 to 1, the angle increases. ; Example: If , then when hour, ;when hour, ;when hour, ; ;in, Indicates the first An angle value in the y-direction; It is an integer index, with a value range from 0 to... , Used to select different angles in sequence; It is the starting angle of this angle sequence, that is, when hour, ; It is the angular interval between two adjacent angles, as... As the angle increases, the angle value increases at this interval; Example: , then when hour, ;when hour, By refining the detection area into multiple small units, it is easier to analyze the underground geological structure and displacement more accurately. In the subsequent angular coordinate calculation process, these grid points can be used as a basis to analyze and process the small units separately, thereby improving the accuracy and precision of monitoring. The regional phase unit 1 also includes a phase difference module 13; Temperature also plays a role in monitoring the topography of the Longmenshan fault zone. Daily temperature variations can reach 15°C, and thermal expansion and contraction can cause deformation of the optical platform in transmitter tower A, affecting the phase consistency of the two-stage OPA. To ensure system stability, the laser beam needs to be split and the phase adjusted in real time. Therefore, the phase difference module 13 receives the angular coordinates from the angle module 12 in the receiving area, as well as historical data extracted from the database. Different monitoring directions are determined using these angular coordinates, which are represented by the angular coordinates. Above, the phase in the monitoring direction is measured using a detector to obtain... Phase measurement at time Then set the reference phase. The error in the monitoring angle direction is calculated based on the measured phase and the reference phase. ; Extracting proportional coefficients from historical data Integral coefficient Differential coefficients The photoelectric conversion coefficient is used, and a PID algorithm combined with error calculation is employed to determine the phase difference that needs to be adjusted in the monitoring angle direction. Specific algorithm formula: By combining angular coordinates for phase adjustment, the impact of deformation on the phase consistency of the two-stage OPA can be compensated more accurately, ensuring the overall phase consistency in the monitoring angular direction. The light intensity distribution in the first to fourth quadrants is obtained by using a four-quadrant detector (QD) installed at the focal point of the central corner reflector of the reflective array. Then perform a double integral to obtain the double integral of the first image. Double integral of the second image Double integral of the third image Double integral of the fourth aspect Calculate the zero-position voltage reference by combining the photoelectric conversion coefficient. Specific algorithm formula: The formula, by combining angular coordinates for zero-position calibration, can accurately determine the zero position in the monitoring direction, thereby improving the accuracy of the measurement. This solves the problem that in the monitoring of the Longmenshan fault zone, where the terrain undulations are large, it is necessary to adjust the beam direction more precisely to ensure the accuracy of the zero position in the angular direction. Historical data includes proportionality coefficients in the angular direction. Integral coefficient Differential coefficients Photoelectric conversion coefficient proportionality coefficient Maximum light intensity value Reference Pattern (Light intensity distribution data at different actual angles is collected using a four-quadrant detector under ideal conditions (such as no atmospheric turbulence and no noise interference), and the light intensity distribution data is used as a reference pattern) and reference temperature. Temperature coefficient of primary coarse-adjustment OPA equipment (It describes the sensitivity of the phase of the primary coarse-tuning OPA device to temperature changes), and the temperature coefficient of the secondary fine-tuning OPA device. (It describes the sensitivity of the phase of a secondary fine-tuned OPA device to temperature changes), angle-phase correlation coefficient ; Angle division unit 2 includes angle judgment module 21 and division generation module 22; Angle determination module 21 is used to receive the zero-position voltage reference from phase difference module 13, monitor the angle direction, and detect the detection area from area angle module 12. Within the detection area, a 256-element primary coarse-tuning OPA device and a 2048-element secondary fine-tuning OPA device are constructed. The spacing between elements in the primary coarse-tuning OPA device is recorded. The spacing between array elements in the secondary fine-tuning OPA device The primary coarse-adjustment OPA device and the secondary fine-adjustment OPA device are connected to the four-quadrant detector respectively for coarse-adjustment OPA large-angle calibration. Since the monitored angle direction includes multiple angles, one angle is randomly selected from the monitored angle direction. One hundred samples were collected using a four-quadrant detector. Multiple sampling and averaging were used to reduce the impact of atmospheric turbulence on the light spot jitter caused by the terrain of the Longmenshan fault zone. Then, the phase value of the 256-element OPA1 device was calculated based on the spacing and angle between the elements. The phase value is applied to the first-level coarse-tuning OPA device, causing the array elements to modulate the phase of the passing light wave according to the phase value. The specific algorithm formula is as follows: ;in, It refers to the first One phase value; A scaling factor is extracted from historical data, and the actual voltage in the monitoring angle direction is collected by a voltage sensor. The voltage change is calculated based on the actual voltage and the zero-point voltage reference. Then, based on the voltage change and the proportional coefficient, the voltage data is converted into the actual angle. The range of actual angles collected, among which, It typically represents a feature length, which plays a normalization role in the formula and is used to adjust the scale of angle calculation; The original light intensity value of the angle is collected by a four-quadrant detector. Record the wavelength of light Then, the maximum light intensity value is extracted from historical data. The light intensity is normalized by combining the original light intensity value, the maximum light intensity value, and the spacing between array elements in the first-level coarse-tuning OPA device, along with the monitoring angle and the wavelength of the light, to obtain the normalized light intensity value. Specific algorithm formula: ;in, This refers to the number of optical components; An angle and its corresponding raw light intensity value are combined to form a data pair. This data pair is then defined as a data point in the data space. A light intensity threshold (e.g., 0.8) is set. The normalized light intensity value is compared with the light intensity threshold to determine whether a data point is valid. When the normalized light intensity value is greater than or equal to the light intensity threshold, the data point is considered valid, and the number of valid points is recorded. When the normalized light intensity value is less than the light intensity threshold, the data points are discarded. A first lookup table is generated by combining the angle, the actual angle, the number of valid points, and the phase value of the 256 array elements. Specific algorithm formula: ;in It refers to the first Angle, actual angle, phase value; generating the first lookup table is the final result of the coarse OPA large angle calibration, which can be used for subsequent control of OPA and adjustment of beam direction. By combining the previously determined monitoring direction and zero-position calibration data, the coarse OPA can more accurately point the beam to the target fracture zone area within the detection area, thereby improving the accuracy of calibration.

[0020] The segmentation generation module 22 is used to receive the first lookup table in the angle judgment module 21, the range of actual angles, and the spacing between array elements in the secondary fine-tuning OPA device, and to obtain adjacent actual angles from the first lookup table. and According to adjacent actual angles and Calculate the first The difference between the actual angles The range of actual angles is divided according to the difference between the actual angles. Each sub-interval corresponds to a difference in an actual angle. This is to prepare for the subsequent secondary fine-tuning; The actual angle is determined based on the difference between the actual angles of the sub-intervals. The range of values This indicates that the range of values ​​for the subinterval is... Then, based on the actual angle Calculate the phase value of 2048 array elements in the secondary fine-tuning OPA device and the spacing between array elements. ,in, This refers to the 2048th array element. A phase value is applied to the 2048-element array to the secondary fine-tuning OPA device. By performing a more precise scan and detection of the beam within each sub-interval, a more accurate beam direction can be found. After applying different phase values ​​to the secondary fine-tuning OPA device, a four-quadrant detector is used to collect light intensity distribution data in the actual scene, receiving light intensity signals corresponding to different actual angles. The light intensity signals are then processed to obtain the actual measured light intensity distribution. ; The range of values ​​in the sub-interval is evenly divided into 50 small angular intervals. The division positions and corresponding angle values ​​are recorded. The angle values ​​corresponding to the division positions are regarded as calibration points (used to record the actual angle information under different phases). Then, a reference pattern is extracted from the historical data. The specific angle of the calibration point is measured using a cross-correlation algorithm based on the actual measured light intensity distribution and the reference pattern. ,in, This refers to mutual functions, from a practical perspective. Specific angles of the calibration point Phase value of 2048 array elements Generate a second lookup table ,in, It refers to the first The actual angle, the specific angle of the calibration point, and the phase value are all determined. Fine-tuning is then performed on the basis of coarse adjustment to further improve the accuracy of beam pointing. Through sub-interval division and micro-scanning, the beam direction can be adjusted more precisely to adapt to the complex detection area environment and the high precision requirements of earthquake monitoring. The compensation synthesis unit 3 receives the angle coordinates from the region angle module 12 and the actual angle from the angle judgment module 21, receives the second lookup table and the first lookup table from the division generation module 22 and the phase difference that needs to be adjusted in the monitored angle direction from the phase difference module 13, and calculates the index corresponding to the coarse adjustment angle based on the angle coordinates and the actual angle. Then, the angular residual is calculated by combining the angular coordinates and the actual angle. ,in, Less than or equal to The fine angle phase interpolation is calculated using the spline interpolation function based on the index corresponding to the angle residual and the coarse adjustment angle, combined with the second lookup table. ; collection Temperature at any time Then retrieve the index corresponding to the specific index from the first lookup table. Raw phase value applied to the primary coarse-tuning OPA device And extracting temperature coefficients from historical data , Reference temperature and angle-phase correlation coefficient, obtained from the original phase value Temperature coefficient Combined with temperature The compensation phase, calculated from the reference temperature and then applied to the primary coarse-tuning OPA device after temperature compensation, is... Then, through precise angular phase interpolation and temperature coefficient... Combined with temperature The compensation phase, calculated from the reference temperature and then applied to the secondary fine-tuning OPA device after temperature compensation, is... ; By using the phase difference that needs to be adjusted along the monitoring angle direction and the angle-phase correlation coefficient, combined with the angle residual, mode coupler compensation is performed to obtain the total phase value. Ultimately, it will compensate for the phase. Compensation phase The phase is synthesized by combining the total phase value and the phase is output as the synthesized phase. The synthesized phase is sent to the OPA device, and the beam direction is adjusted to the detection area. By combining the monitoring of angular coordinates and the phase adjustment of the actual angle with the OPA device technology, the beam direction is dynamically adjusted to ensure that the seismic monitoring can quickly respond to subtle changes in seismic activity in complex environments, thus ensuring the efficient operation of seismic monitoring in complex environments.

[0021] The invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples of the invention and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A multi-stage cascaded large-angle beam deflection control system based on an optical phased array, characterized in that: It includes a regional phase unit (1), an angle division unit (2), and a compensation synthesis unit (3); The regional phase unit (1) is configured to acquire the scanning angle coordinates of the target region and calculate the phase difference that needs to be adjusted in the direction of the scanning angle coordinates; The angle division unit (2) is communicatively connected to the region phase unit (1) and is configured to calibrate the first-level coarse-tuning optical phased array and the second-level fine-tuning optical phased array based on the scanning angle coordinates and phase difference, and generate a first lookup table corresponding to the first-level coarse-tuning optical phased array and a second lookup table corresponding to the second-level fine-tuning optical phased array. The compensation synthesis unit (3) is communicatively connected to the region phase unit (1) and the angle division unit (2), and is configured to query the first lookup table to obtain the first-level coarse adjustment index and angle residual based on the current target scanning angle coordinates, and query the second lookup table based on the angle residual to obtain the fine angle phase interpolation; the compensation synthesis unit is also configured to combine the phase difference, the phase value corresponding to the first-level coarse adjustment index and the fine angle phase interpolation to perform temperature compensation and phase synthesis, and generate and output a synthesized phase signal for driving the first-level coarse adjustment optical phased array and the second-level fine adjustment optical phased array.

2. The multi-stage cascaded large-angle beam deflection control system based on optical phased array according to claim 1, characterized in that: The regional phase unit (1) includes a coordinate transformation module (11) and a regional angle module (12); The coordinate transformation module (11) collects the WGS-84 coordinate system of the established stations A and B, and obtains the coordinates of stations A and B from the WGS-84 coordinate system; Obtain the longitude and latitude of station A to derive the rotation matrix around the z-axis and the rotation matrix around the y-axis. Combine the rotation matrix around the z-axis and the rotation matrix around the y-axis, first perform the rotation around the y-axis, and then perform the rotation around the z-axis to obtain the complete rotation matrix from the WGS-84 coordinate system to the NED coordinate system. The coordinates of station A in the WGS-84 coordinate system are converted to coordinates in the NED coordinate system using the complete rotation matrix and the coordinates of station A in the WGS-84 coordinate system. The region angle module (12) is used to receive the rotation matrix, A-site coordinates and B-site coordinates in the coordinate transformation module (11), and calculate the reference vector and the components of the reference vector in the WGS-84 coordinate system respectively; Based on the components of the reference vector in the WGS-84 coordinate system, the components of the reference vector in the NED coordinate system are calculated using the rotation matrix. The detection area is determined by the components of the reference vector in the NED coordinate system, thus obtaining the range of the detection area.

3. The multi-stage cascaded large-angle beam deflection control system based on an optical phased array according to claim 2, characterized in that: The region angle module (12) further includes the following steps: The detection area is divided into grids into multiple small units, and the number of units in the horizontal and vertical directions of the detection area is recorded. Each small unit within the detection area corresponds to a grid point, and each grid point corresponds to an angular coordinate. The angular coordinates are calculated based on the scope of the detection area and the number of units divided in the horizontal and vertical directions.

4. The multi-stage cascaded large-angle beam deflection control system based on an optical phased array according to claim 3, characterized in that: The regional phase unit (1) also includes a phase difference module (13); The phase difference module (13) receives the angular coordinates in the area angle module (12) and uses the angular coordinates to determine different monitoring directions; The phase in the monitoring direction is measured using a detector to obtain... The error in the monitoring angle direction is calculated by measuring the phase at a given moment; Historical data is extracted from the database, and then proportional, integral, and differential coefficients are extracted from the historical data. Combined with the error calculation, the phase difference that needs to be adjusted in the monitoring angle direction is calculated. The light intensity distribution in the first to fourth quadrant regions is obtained by a four-quadrant detector, and then double integration is performed to obtain the double integral from the first to the fourth quadrant. The zero-position voltage reference is calculated by combining the photoelectric conversion coefficient in historical data.

5. The multi-stage cascaded large-angle beam deflection control system based on an optical phased array according to claim 4, characterized in that: The angle division unit (2) includes an angle judgment module (21) and a division generation module (22); The angle judgment module (21) is used to receive the zero voltage reference in the phase difference module (13), the monitoring angle direction, and the detection area in the area angle module (12); A primary coarse-tuning OPA device with 256 elements and a secondary fine-tuning OPA device with 2048 elements were set up in the detection area, and the spacing between the elements in the primary coarse-tuning and secondary fine-tuning OPA devices was recorded. The monitoring angle direction includes multiple angles. An angle is randomly selected from the monitoring angle direction, and the phase value of the 256 array elements is calculated in combination with the spacing between the array elements in the 256 array element OPA1 device. The phase value is applied to the first-level coarse-tuning OPA device, so that the array elements modulate the phase of the passing light wave according to the phase value; The actual voltage in the monitoring angle direction is collected by a voltage sensor, and the voltage change is calculated by combining it with the zero-position voltage reference. Extract the scaling factor from historical data, combine it with voltage change to convert voltage data into actual angle, and collect the range of actual angle. The division generation module (22) is used to receive the first lookup table in the angle judgment module (21), the range of actual angles, and the spacing between array elements in the secondary fine-tuning OPA device, and to obtain adjacent actual angles from the first lookup table to calculate the difference of actual angles; The range of actual angles is divided according to the difference in actual angles. Each sub-interval corresponds to a difference in an actual angle; The actual angle is determined based on the difference between the actual angles of the sub-intervals. The range of values ​​for is the range of values ​​for the subinterval.

6. The multi-stage cascaded large-angle beam deflection control system based on an optical phased array according to claim 5, characterized in that: The angle determination module (21) further includes the following steps: The original light intensity value at the acquisition angle is combined with the maximum light intensity value in historical data and the spacing between array elements in the first-level coarse-tuning OPA device and the monitoring angle direction to normalize the light intensity and obtain the normalized light intensity value. The angle and the corresponding original light intensity value are combined into a data pair and defined as a data point in the data space. The normalized light intensity value is used to determine whether the data point is a valid point. Once a data point is determined to be a valid point, the number of valid points is recorded, and a first lookup table is generated by combining the angle, the actual angle, and the phase value of the 256 array elements.

7. The multi-stage cascaded large-angle beam deflection control system based on an optical phased array according to claim 6, characterized in that: The partitioning generation module (22) further includes the following steps: From a practical perspective The phase value of 2048 array elements is calculated based on the spacing between array elements in the secondary fine-tuning OPA device, and the phase value of 2048 array elements is applied to the secondary fine-tuning OPA device. A four-quadrant detector is used to collect actual light intensity distribution data, receive light intensity value signals corresponding to different actual angles, and process the light intensity value signals to obtain the actual measured light intensity distribution. Divide the range of values ​​of the sub-interval into 50 small angular intervals, record the division position and the corresponding angle value, and regard the angle value corresponding to the division position as the calibration point. The specific angle of the calibration point is measured using a cross-correlation algorithm based on the actual measured light intensity distribution and a reference pattern from historical data. From a practical perspective The specific angles of the calibration points and the phase values ​​of the 2048 array elements are used to generate a second lookup table.

8. The multi-stage cascaded large-angle beam deflection control system based on an optical phased array according to claim 7, characterized in that: The compensation synthesis unit (3) is used to receive the angle coordinates in the area angle module (12) and the actual angle in the angle judgment module (21), and to receive the second lookup table, the first lookup table in the division generation module (22) and the phase difference in the monitoring angle direction that needs to be adjusted in the phase difference module (13); Calculate the index corresponding to the coarse adjustment angle based on the angle coordinates and the actual angle, and then calculate the angle residual based on the angle coordinates and the actual angle. The fine angle phase interpolation is calculated using the spline interpolation function based on the index corresponding to the angle residual and the coarse adjustment angle, combined with the second lookup table. The original phase value corresponding to the specific index is obtained from the first lookup table and applied to the first-level coarse-tuning OPA device. The temperature-compensated phase is then calculated based on the original phase value, combined with the temperature coefficient and reference temperature in the historical data, and applied to the first-level coarse-tuning OPA device after temperature compensation. Then, through precise angular phase interpolation, combined with the temperature coefficient from historical data... The compensation phase, calculated with reference temperature and then applied to the secondary fine-tuning OPA device after temperature compensation, is then applied.

9. The multi-stage cascaded large-angle beam deflection control system based on an optical phased array according to claim 8, characterized in that: The compensation synthesis unit (3) further includes the following steps: By using the phase difference that needs to be adjusted in the monitoring angle direction, combined with the angle-phase correlation coefficient and angle residual in historical data, mode coupler compensation is performed to obtain the total phase value; The compensated phase and the total phase value are combined to output the combined phase, which is then sent to the OPA device to adjust the beam direction to the detection area.

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