A method and system for calibrating azimuth angle of a gimbal device
By calibrating the included angle before the PTZ device leaves the factory and binding the azimuth angle with a GNSS antenna on site, the problem of low accuracy in azimuth angle measurement of PTZ device is solved, and high-precision, low-cost batch calibration is achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHENZHEN BEIDOUYUN INFORMATION TECH CO LTD
- Filing Date
- 2023-07-31
- Publication Date
- 2026-07-31
AI Technical Summary
In existing technologies, the azimuth angle measurement of gimbal equipment mainly relies on manual compass calibration, which is affected by the geomagnetic field and local environment, resulting in low accuracy and making it unsuitable for mass production.
Before the PTZ device leaves the factory, the first and second direction points are calibrated, the included angle is recorded and written into the GNSS module. After on-site installation, the azimuth angle is measured through the first and second GNSS antennas, and the relationship between the PTZ reading and the due north azimuth angle is bound using the GNSS module.
It achieves high-precision azimuth angle calibration of gimbal equipment, avoids the influence of geomagnetic field and local environment, has simple structure and low cost, and is suitable for batch calibration.
Smart Images
Figure CN117213525B_ABST
Abstract
Description
[Technical Field]
[0001] This invention relates to the field of video surveillance technology, and in particular to a method and system for calibrating the azimuth angle of a pan-tilt-zoom (PTZ) device. [Background Technology]
[0002] With the continuous development of the intelligent industry, video surveillance is widely used in many situations due to its intuitiveness, accuracy, timeliness, and rich information content. For video surveillance scenarios such as forest fire prevention, agriculture, forestry and animal husbandry, farmland occupation, and geological disaster monitoring, relying on BeiDou Cloud GNSS high-precision positioning and orientation technology, and through terminal modules, antennas, and calibration system algorithms, high-precision data output for pan-tilt-zoom (PTZ) positioning and orientation can be achieved. The video ranging and thermal infrared technologies of the PTZ equipment can identify risk points and determine the location of risks, facilitating timely hazard mitigation by personnel.
[0003] To accurately obtain the coordinates of objects within the field of view of a gimbal, it is necessary to calibrate the azimuth angle of the gimbal. Azimuth angle, also known as horizontal longitude, is one of the methods for measuring the angular difference between objects on a plane. The azimuth angle is the horizontal angle between the north direction line from a point and the target direction line in a clockwise direction.
[0004] Currently, the determination of the azimuth angle of gimbal equipment is mainly done manually on-site using a compass, which indicates magnetic north. This method is greatly affected by the geomagnetic field and local environment, has low accuracy, and is costly in terms of manpower and time, and cannot be used in large quantities.
[0005] CN107040752B discloses an intelligent dome camera, comprising a camera module, a pan-tilt calibration system, a camera motherboard, and an electronic compass. The electronic compass measures geomagnetic field data and / or acceleration data in a specified direction, and sends the geomagnetic field data and / or the acceleration data to the camera motherboard. The camera motherboard determines a north-pointing direction based on the geomagnetic field data from the electronic compass and uses it as a reference for calibrating the azimuth angle of the camera lens. The camera motherboard obtains the location information of the intelligent dome camera through a GPS module. However, the magnetic north direction is greatly affected by the geomagnetic field and local environment, resulting in low accuracy of the measured azimuth angle and large errors in the location information obtained by the GPS module. Furthermore, the solution disclosed in this patent can only be operated in the field and cannot be mass-produced for use in different products.
[0006] Therefore, it is necessary to provide a new method and system for calibrating the azimuth angle of a gimbal device to solve the above-mentioned technical problems. [Summary of the Invention]
[0007] The purpose of this invention is to provide a calibration method and system for calibrating the azimuth angle of gimbal devices of different products with high accuracy and batch calibration capability, so as to solve the problems in related technologies.
[0008] To achieve the above objectives, the present invention provides a method for calibrating the azimuth angle of a gimbal device, comprising the following steps:
[0009] S101, Before the gimbal device leaves the factory, a first calibration point and a second calibration point are calibrated on the gimbal device, and the direction from the first calibration point to the second calibration point is the first direction;
[0010] S102, calibrate and record the angle △R between the default optical axis direction of the gimbal device and the first direction at the time of manufacture, and write it into the GNSS module;
[0011] S103, after the gimbal device is installed on site, the azimuth angle of the first direction is measured using the first GNSS antenna and the second GNSS antenna, and the gimbal reading of the gimbal device is converted into a binding relationship with the due north azimuth angle based on the included angle △R.
[0012] More preferably, in step S103, before the gimbal device is installed on site, the first GNSS antenna and the second GNSS antenna are respectively installed at the first calibration point and the second calibration point.
[0013] More preferably, in step S103, before the gimbal device is installed on site, the first GNSS antenna and the second GNSS antenna are assembled on a calibration tool, the calibration tool is installed on the gimbal device, and the calibration tool is set along the first direction.
[0014] More preferably, step S102 specifically includes: recording the gimbal reading R1 of the factory default optical axis direction of the gimbal device, controlling the gimbal device to rotate, and when the optical axis direction of the gimbal device is the same as the first direction, recording the gimbal horizontal angle reading R2 of the gimbal device, calculating the difference between the two readings ΔR = R2 - R1, and writing it into the GNSS module.
[0015] To achieve the above objectives, the present invention also provides a calibration system, which includes a computer, a gimbal device, a GNSS module, a communication module, a first GNSS antenna, and a second GNSS antenna.
[0016] More preferably, the gimbal device includes a gimbal and a camera or laser LIDAR device assembled on the gimbal.
[0017] More preferably, the gimbal device includes two mounting holes, and the first GNSS antenna and the second GNSS antenna are respectively mounted in the two mounting holes.
[0018] More preferably, the two mounting holes are located on the surface of the camera away from the pan-tilt unit.
[0019] More preferably, the calibration system further includes a calibration tool installed on the gimbal device, wherein the first GNSS antenna and the second GNSS antenna are installed on the calibration tool.
[0020] More preferably, the calibration tool includes a first mounting hole and a second mounting hole located at both ends thereto, and the first GNSS antenna and the second GNSS antenna are respectively mounted in the first mounting hole and the second mounting hole.
[0021] The beneficial effects of the azimuth calibration method for a gimbal device provided by the present invention are as follows: by using the first GNSS antenna and the second GNSS antenna to achieve the advantage of simultaneous positioning and orientation, the gimbal reading is bound to the azimuth angle, and the true north direction is indicated. It is not affected by the geomagnetic field and the local environment, and has high accuracy.
[0022] The advantages of the calibration system provided by this invention are: simple structure, low cost, and can be used to calibrate similar products. [Attached Image Description]
[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:
[0024] Figure 1 This is a flowchart of a method for calibrating the azimuth angle of a gimbal device according to the present invention;
[0025] Figure 2 This is a schematic diagram of the GNSS module used in this invention;
[0026] Figure 3 This is a partial schematic diagram of an embodiment of the calibration system of the present invention;
[0027] Figure 4 This is a schematic diagram of a second embodiment of the calibration system of the present invention;
[0028] Figure 5 This is an exploded view of Example 2;
[0029] Figure 6 This is a schematic diagram illustrating the principle of verifying the feasibility of measuring azimuth using GNSS orientation.
[0030] Figure 7This is a schematic diagram to verify the principle of improving accuracy by using different antenna distances.
Detailed Implementation Methods
[0031] The technical solutions of 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 a part of the embodiments of the present invention, and not all of them. 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.
[0032] like Figure 1 As shown, the present invention provides a method for calibrating the azimuth angle of a gimbal device, which includes the following steps:
[0033] S101, Before the gimbal equipment leaves the factory, the first calibration point and the second calibration point are calibrated on the gimbal equipment. The direction from the first calibration point to the second calibration point is the first direction.
[0034] S102, calibrate and record the angle △R between the default optical axis direction of the PTZ device and the first direction at the time of manufacture, and write it into the GNSS module;
[0035] S103 After the PTZ device is installed on site, the azimuth angle in the first direction is measured using the first GNSS antenna and the second GNSS antenna. The relationship between the PTZ device reading and the due north azimuth angle is calculated based on the included angle △R.
[0036] Specifically, in step S103, before the gimbal device is installed on site, the first GNSS antenna and the second GNSS antenna are set along the first direction.
[0037] Specifically, step S102 includes: recording the gimbal reading R1 of the factory default optical axis direction of the gimbal device; controlling the gimbal device to rotate so that the optical axis direction of the gimbal device is the same as the first direction; recording the gimbal horizontal angle reading R2 of the gimbal device; calculating the difference between the two readings ΔR = R2 - R1; and writing it into the GNSS module.
[0038] Specifically, a laser tool can be used to emit a laser towards the target along the first direction, and the position P of the laser on the target can be recorded. The horizontal angle reading R1 of the gimbal device can be recorded. The gimbal device can be controlled to rotate so that the optical axis of the gimbal device is aligned with the position P of the target. The horizontal angle reading R2 of the gimbal device can be recorded. The difference between the two readings ΔR = R2 - R1 can be calculated.
[0039] Specifically, in other embodiments, a crossbar or ruler can be set in the first direction, and an angle measuring instrument can be used to measure the angle △R between the default factory optical axis direction of the gimbal device and the first direction.
[0040] The principle of the azimuth angle calibration method of the PTZ device of the present invention is as follows: a first direction is determined by a first calibration point and a second calibration point. Then, the angle △R between the default factory optical axis direction of the PTZ device and the first direction is calibrated. After the PTZ device is installed on site, the first GNSS antenna and the second GNSS antenna are used for positioning at the same time to generate two coordinates. The angle between the vector direction of the first GNSS antenna and the second GNSS antenna is the azimuth angle of the first direction, thereby obtaining the binding between the PTZ reading and the azimuth angle.
[0041] This invention provides a calibration system employing a method for calibrating the azimuth angle of a pan-tilt-zoom (PTZ) device. The system includes a computer, a PTG device, a GNSS module, a communication module, a first GNSS antenna, and a second GNSS antenna. The PTG device includes a pan-tilt unit and a camera or laser LiDAR device assembled on the PTG device, but is not limited thereto. Specifically, a coaxial camera can be installed on the laser LiDAR device, and the azimuth angle of the PTG device can be calibrated using the optical axis of the coaxial camera. Alternatively, the azimuth angle of the PTG device can be directly calibrated using the optical axis of the laser LiDAR device, but is not limited thereto. The camera can be a thermal imaging camera, a multispectral camera, a hyperspectral camera, etc., but is not limited thereto.
[0042] like Figure 2 As shown, the GNSS module includes a GNSS receiver, a control module, a Bluetooth module, and a power management module.
[0043] GNSS modules are used to receive satellite signals from multiple satellite calibration systems, such as GPS / BDS / GLONASS / GALILEO / QZSS, and to locate themselves by receiving latitude and longitude coordinate information provided by the satellites.
[0044] The first and second GNSS antennas can be spiral antennas suitable for field use, supporting multiple frequency points of the four calibration systems of GPS, BDS, GLONASS, and GALILEO. They have the advantages of high gain, wide beamwidth, good reception of low elevation angle signals, high stability, and strong anti-interference.
[0045] Example 1
[0046] like Figure 3 As shown, the calibration system in this embodiment includes a computer, a GNSS module, a communication module, a PTZ device 1, a first GNSS antenna 21, and a second GNSS antenna 22.
[0047] In this embodiment, the gimbal device 1 includes a gimbal 11 that can rotate along a horizontal angle and a camera 12 assembled on the gimbal 11.
[0048] The calibration system also includes a laser tool 3 and a target 4.
[0049] The calibration steps for the calibration system include:
[0050] S301, Before the pan-tilt device 1 leaves the factory, a first calibration point 121 and a second calibration point 122 are calibrated on the pan-tilt device 1. The direction from the first calibration point 121 to the second calibration point 122 is the first direction. The first calibration point 121 and the second calibration point 122 are two mounting holes set on the surface of the camera 12 away from the pan-tilt device 11.
[0051] S302, use laser tool 3 to emit laser towards target 4 along the first direction, record the position P of the laser on target 4, record the horizontal angle reading R1 of gimbal device 1, control gimbal device 1 to rotate, so that the optical axis of gimbal device 1 is aligned with the position P of target 4, record the horizontal angle reading R2 of gimbal device 1, calculate the difference between the two readings ΔR=R2-R1, and write it into the GNSS module;
[0052] S303, the first GNSS antenna 21 and the second GNSS antenna 22 are installed at the first calibration point 121 and the second calibration point 122 respectively. After the gimbal device 1 is installed on site, the azimuth angle of the first direction is measured by the first GNSS antenna 21 and the second GNSS antenna 22. The gimbal reading of the gimbal device 1 is converted into the binding relationship with the due north azimuth angle based on the included angle △R.
[0053] Specifically, in step S302, the method for determining the position P of the optical axis direction of the gimbal device 1 aligned with the target 4 can be determined by human eye, or by computer image processing software working together with camera 12 to automatically identify the position P as being located at the imaging center of the gimbal device through edge value comparison.
[0054] Specifically, the positions of the first calibration point 121 and the second calibration point 122 are not limited; they can be located at the center of the camera 12 or at the two ends of the diagonal of the camera 12.
[0055] The laser tool 3 can be fixed to the top of the camera 12 with screws, but is not limited to this.
[0056] Example 2
[0057] like Figure 4 , Figure 5 As shown, compared with Embodiment 1, the calibration system in this embodiment further includes a calibration tool 23. The calibration tool 23 includes a first mounting hole 231 and a second mounting hole 232 located at its two ends, and the shapes of the first mounting hole 231 and the second mounting hole 232 are different. A foolproof design ensures that the antenna's installation direction on-site is consistent with the installation direction during calibration. The calibration tool 23 can be a horizontal bar.
[0058] The calibration steps for the calibration system include:
[0059] S401, Before the pan-tilt device 1 leaves the factory, a first calibration point 121 and a second calibration point 122 are calibrated on the pan-tilt device 1. The direction from the first calibration point 121 to the second calibration point 122 is the first direction. The first calibration point 121 and the second calibration point 122 are mounting holes set on the surface of the camera 12 away from the pan-tilt device 11.
[0060] S402, use laser tool 3 to emit laser towards target 4 in the first direction, record the position P of the laser on target 4, record the horizontal angle reading R1 of gimbal device 1, control gimbal device 1 to rotate, so that the optical axis of gimbal device 1 is aligned with the position P of target 4, record the horizontal angle reading R2 of gimbal device 1, calculate the difference between the two readings ΔR=R2-R1, and write it into GNSS module;
[0061] S403, the first GNSS antenna 21 and the second GNSS antenna 22 are respectively installed in the first mounting hole 231 and the second mounting hole 232 of the calibration tool 23. The calibration tool 23 is installed on the pan-tilt device 1 and the calibration tool 23 is set along the first direction. After the pan-tilt device 1 is installed on site, the azimuth angle of the first direction is measured by the first GNSS antenna 21 and the second GNSS antenna 22. The pan-tilt reading of the pan-tilt device 1 and the binding relationship with the due north azimuth angle are calculated according to the included angle ΔR.
[0062] Specifically, in step S402, the method for determining the position P of the optical axis direction of the gimbal device 1 aligned with the target 4 can be determined by human eye, or by using computer image processing software in conjunction with the camera 12 to automatically identify the position P as being located at the imaging center of the gimbal device through edge value comparison.
[0063] The calibration tool 23 also includes a first aiming hole 233 and a second aiming hole 234 located between the first mounting hole 231 and the second mounting hole 232.
[0064] The finer the beam diameter of the laser tool 3, the better. The beam is adjusted to pass through the first aiming hole 233 and the second aiming hole 234 to achieve precise alignment, ensuring that the first aiming hole 233, the second aiming hole 234 and the first mounting hole 231 and the second mounting hole 232 are on the same axis.
[0065] Specifically, the laser tool 3 can be installed in the first aiming hole 233 and the second aiming hole 234 by screws, but it is not limited to this.
[0066] In this embodiment, the first calibration point 121 and the second calibration point 122 coincide with the first aiming hole 233 and the second aiming hole 234, respectively.
[0067] By designing the calibration tool 23, the distance between the first GNSS antenna 21 and the second GNSS antenna 22 can be increased, thereby improving the calibration accuracy.
[0068] The beneficial effects of the azimuth angle calibration method for a gimbal device provided by the present invention are as follows: by achieving the advantages of simultaneous positioning and orientation through the first GNSS antenna and the second GNSS antenna, the gimbal reading and the optical axis azimuth angle of the gimbal device are bound together, and the true north direction is indicated, which is not affected by the geomagnetic field and the local environment, and has high accuracy.
[0069] The advantages of the calibration system provided by this invention are: simple structure, low cost, and it can be used to calibrate similar products, such as PTZ cameras, PTZ laser LIDAR devices, etc., but not limited thereto.
[0070] To verify the feasibility of using GNSS orientation to measure azimuth, a comparative test was conducted between the azimuth calculated using GNSS coordinates and the azimuth calculated using a total station.
[0071] 1) Test method description: such as Figure 6 As shown, the coordinates of three marker points (A / B / C) are measured using GNSS, and the azimuth angles and their differences between AB and AC are calculated using these coordinates. The difference in angle changes between AB and AC is measured using a total station. The angle changes of the GNSS, fixed on the total station's rotating platform, are read twice. The three sets of data are compared to achieve accurate azimuth angle measurement.
[0072] 2) Test data
[0073] Coordinates of the three points:
[0074] GNSS coordinates of point A: 22.65696294047, 113.99938914578, 97.4867
[0075] GNSS coordinates of point B: 22.65683770558, 113.99964278853, 97.4260
[0076] GNSS coordinates of point C: 22.65671296170, 113.99949896984, 97.4540
[0077] The calculated azimuth of AB is 118.012107°, and its length is 29.529 meters.
[0078] The calculated azimuth of AC is 157.816483°, and its length is 29.896 meters.
[0079] The angular deviation between AB and AC is 39.804376°.
[0080] Total station surveying:
[0081] Distance from total station (point A) to point B: 29.530 meters, angle 0°00′00″
[0082] At this moment, the GNSS azimuth is 208.4856° (average over 1 minute).
[0083] Distance from total station (point A) to point C: 29.892 meters, angle 39°47′25″
[0084] The angular deviation between the two locations was measured to be 39.7903° using a total station.
[0085] At this moment, the GNSS azimuth is 248.2851° (average over 1 minute).
[0086] The azimuth difference between the two locations measured using GNSS is 39.7995°.
[0087] 3) Test Conclusion
[0088] ① Using the total station as the true reference angle, the difference between the angle obtained by measuring with coordinates and the angle obtained by measuring with coordinates is 0.014°, and the difference between the angle obtained by measuring the azimuth using GNSS and the angle obtained by measuring with coordinates is 0.0092°.
[0089] ② GNSS coordinates, as a method for calculating distance and azimuth, can provide an angular change accuracy within 0.1° and a distance accuracy of 3mm.
[0090] ③ Using a dual-antenna GNSS method for direction finding can accurately measure angular changes. The accuracy can reach within 0.1°.
[0091] Performance verification
[0092] The main purpose of this test is to determine the accuracy of GNSS orientation at different dual-antenna distances and the effect of time-period algorithms on improving accuracy.
[0093] Test method description: such as Figure 7 As shown, using a total station (simulating a pan-tilt unit) and a GNSS mounting bracket, the difference between the changes in antenna azimuth and total station angle was observed by adjusting the distance between the two antennas on the mounting bracket. The recorded data was then used to evaluate the improvement in accuracy using a time-period algorithm.
[0094] 1) Test data
[0095] a. Comparison of measurements at approximately 86.5 cm:
[0096] 1min 263.0756 248.6618 14.4138 14.6222 0.2084 2min 263.1012 248.6624 14.4388 14.6222 0.1834 3min 263.1444 248.669 14.4754 14.6222 0.1468 4min 263.1447 248.6748 14.4699 14.6222 0.1523 5min 263.1123 248.6752 14.4371 14.6222 0.1851
[0097] Based on the data comparison table above, the azimuth accuracy is within 0.2° when the distance between the two antennas is around 86cm; the accuracy is highest when the data is calculated over a 3-minute time period; and the accuracy cannot be significantly improved by averaging the data over a longer time period.
[0098] b. Comparison of tests at approximately 67 cm:
[0099] 1min 263.2588 248.4715 14.7873 14.6222 0.1651 2min 263.2656 248.3217 14.9439 14.6222 0.3217 3min 263.2668 248.3838 14.883 14.6222 0.2608 4min 263.26 248.462 14.798 14.6222 0.1758 5min 263.2502 248.5317 14.7185 14.6222 0.0963
[0100] Based on the data comparison table above, the azimuth accuracy is approximately 0.1° to 0.3° when the distance between the two antennas is around 67cm; the accuracy is highest when the data is calculated over a 5-minute time period; and the accuracy can be improved by using an averaging algorithm for extended time periods.
[0101] c. Comparison test results at approximately 56 cm:
[0102] 1min 262.7723 248.6447 14.1276 14.6222 0.4946 2min 262.7176 248.5355 14.1821 14.6222 0.4401 3min 262.7254 248.4698 14.2556 14.6222 0.3666 4min 262.6907 248.4548 14.2359 14.6222 0.3863 5min 262.7055 248.2968 14.4087 14.6222 0.2135
[0103] Based on the data comparison table above, the azimuth accuracy is approximately 0.2° to 0.5° when the distance between the two antennas is around 56cm; the accuracy is highest when the data is calculated over a 5-minute time period; and the accuracy can be improved by using an averaging algorithm for extended time periods.
[0104] d. Comparison test results at approximately 39 cm:
[0105] 1min 264.2589 250.0764 14.1825 14.6222 0.4397 2min 264.6625 250.2002 14.4623 14.6222 0.1599 3min 264.8462 250.3142 14.532 14.6222 0.0902 4min 264.8538 250.4171 14.4367 14.6222 0.1855 5min 264.9196 250.478 14.4416 14.6222 0.1806
[0106] Based on the data comparison table above, the azimuth accuracy is approximately 0.1° to 0.4° when the distance between the two antennas is around 39cm; the accuracy is highest when the data is calculated over a 3-minute time period; extending the time period does not significantly improve the accuracy using the averaging algorithm.
[0107] 3) Test Conclusion
[0108] ① When the distance between the two antennas is about 86cm, the azimuth accuracy is within 0.2°;
[0109] ② When the distance between the two antennas is about 67cm, the azimuth accuracy is about 0.1° to 0.3°;
[0110] ③ When the distance between the two antennas is about 56cm, the azimuth accuracy is about 0.2° to 0.5°;
[0111] ④ When the distance between the two antennas is about 39cm, the azimuth accuracy is about 0.1° to 0.4°;
[0112] ⑤ Using time-period solutions can improve azimuth accuracy. In certain scenarios, the averaging algorithm can improve accuracy. Further testing is needed to find a more general algorithm that meets the needs of different scenarios.
[0113] Note: The test site is an open-air platform constructed of wooden planks. The bubble level indicates that human movement may have caused the instrument to tilt, which slightly interferes with the test results.
[0114] In summary, the beneficial effects of the azimuth calibration method and calibration system for a gimbal device of the present invention are as follows: Simultaneous positioning using a first GNSS antenna and a second GNSS antenna generates two coordinates. The angle between the vector direction of the first GNSS antenna and the second GNSS antenna is the azimuth angle. Furthermore, by utilizing the advantages of laser's good directionality, monochromaticity, and high brightness, as well as the high precision of the gimbal in recording rotational changes, the angular relationship between the dual antenna positions and the fixed optical axis is measured, thereby obtaining the binding of the gimbal reading and the azimuth angle. This improves positioning accuracy, indicates true north rather than magnetic north, is unaffected by the geomagnetic field and local environment, has relatively uniform accuracy, and is low in cost and maintenance.
[0115] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for calibrating an azimuth angle of a gimbal device, characterized in that, It includes the following steps: S101, Before the gimbal device leaves the factory, a first calibration point and a second calibration point are calibrated on the gimbal device, and the direction from the first calibration point to the second calibration point is the first direction; S102, calibrate and record the angle △R between the default optical axis direction of the gimbal device and the first direction at the time of manufacture, and write it into the GNSS module; S103, after the gimbal device is installed on site, the azimuth angle of the first direction is measured using the first GNSS antenna and the second GNSS antenna, and the gimbal reading of the gimbal device is converted into a binding relationship with the due north azimuth angle based on the included angle △R. In step S103, before the gimbal device is installed on site, the first GNSS antenna and the second GNSS antenna are respectively installed at the first calibration point and the second calibration point; or, in step S103, before the gimbal device is installed on site, the first GNSS antenna and the second GNSS antenna are assembled on a calibration tool, the calibration tool is installed on the gimbal device, and the calibration tool is set along the first direction; The steps of step S102 specifically include: recording the gimbal reading R1 of the factory default optical axis direction of the gimbal device, controlling the gimbal device to rotate, and when the optical axis direction of the gimbal device is the same as the first direction, recording the gimbal horizontal angle reading R2 of the gimbal device, calculating the difference between the two readings ΔR=R2-R1, and writing it into the GNSS module.
2. A calibration system characterized by, It includes a computer, a PTZ device, a GNSS module, a communication module, a first GNSS antenna, and a second GNSS antenna; The computer is used to execute the azimuth angle calibration method for the gimbal device as described in claim 1.
3. The calibration system according to claim 2, characterized in that, The gimbal device includes a gimbal and a camera or laser LIDAR device assembled on the gimbal.
4. The calibration system according to claim 3, characterized in that, The gimbal device includes two mounting holes, and the first GNSS antenna and the second GNSS antenna are respectively mounted in the two mounting holes.
5. A calibration system according to claim 4, characterized in that, The two mounting holes are located on the surface of the camera away from the pan-tilt unit.
6. A calibration system according to claim 3, characterized in that, The calibration system also includes a calibration tool installed on the gimbal device, and the first GNSS antenna and the second GNSS antenna are installed on the calibration tool.
7. A calibration system according to claim 6, characterized in that, The calibration tool includes a first mounting hole and a second mounting hole at its two ends, and the first GNSS antenna and the second GNSS antenna are respectively mounted in the first mounting hole and the second mounting hole.