A method of calibrating an astronomical navigation device

Abstract

The present application provides a kind of calibration method of astronomical navigation equipment, including optical calibration method and digital calibration method, optical calibration method first calibrates calibration tool with ship reference collation, then collation of the azimuth of star tracker base, level and calibration tool, finally, according to the calibration deviation, correction is carried out, so that the output information of astronomical navigation is unified with the real state of ship. Digital calibration method synchronously records ship main inertial navigation and astronomical navigation equipment navigation data, calculates the navigation deviation angle of two equipment through software, and is bound to astronomical navigation equipment, to realize the unity of astronomical navigation equipment and ship reference. The calibration method of the present application fills the gap of ship technology class based on laser gyro astronomical navigation equipment floating state calibration and digital calibration method in the market, solves the problem of detecting and correcting the zero position of high-precision equipment under the condition and engineering environment, and to some extent, provides the means of increasing the information output equipment of ship navigation system.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of shipbuilding, in particular to a method for calibrating an astronomical navigation device. BACKGROUND

[0002] With the emergence of large ships and other navigation positioning requirements, under the impetus of engineering needs, astronomical navigation equipment is installed as a backup means for satellite navigation equipment, and the positioning capability in complex electromagnetic environments is improved, which has become a demand for more and more large ship equipment technology assembly. The astronomical navigation equipment mainly includes a star tracker, a laser gyro inertial device, a display control box, and a power control box. The main components are the star tracker and the laser gyro inertial device, which form an integrated measurement unit. The improvement of astronomical star measurement capability and the application of astronomical and inertial deep combination navigation technology enable the astronomical navigation equipment to complete its main functions in a relatively complex electromagnetic environment. The application of astronomical and inertial deep combination navigation technology is an important part of the integrated navigation system. The directional accuracy of the astronomical navigation equipment on the ship reaches the angle second level, and has become one of the highest heading measurement means. The all-solid-state of the star tracking measurement unit and the photoelectric inertial measurement unit, and the rigid integration of the two, make the reliability of the astronomical navigation equipment reach thousands of hours, which improves the support for long navigation time and continuous navigation of large ships.

[0003] Many previous ships do not install astronomical navigation equipment. In order to solve the problem of installing astronomical navigation equipment after the ship is launched and meet the installation precision requirements, realize the calibration of the astronomical navigation equipment in the wharf state after the ship is launched, according to the implementation conditions on site, the present application provides a method for calibrating an astronomical navigation device. SUMMARY

[0004] In view of the above-mentioned shortcomings of the prior art, the problem to be solved by the present application is to provide a method for calibrating an astronomical navigation device on a ship, which solves the problem of installing astronomical navigation equipment after the ship is launched and meets the installation precision requirements, realizes the calibration of the astronomical navigation equipment in the wharf state after the ship is launched, and selects optical calibration or digital calibration method according to the implementation conditions on site to realize the unification of the astronomical navigation equipment and the ship reference.

[0005] To achieve the above object and other related objects, the present application provides a method for calibrating an astronomical navigation device, characterized in that it comprises an optical calibration method and a digital calibration method, and the optical calibration method comprises the following steps:

[0006] S1: providing an auxiliary tool, the auxiliary tool comprising a calibration tool and a theodolite support, the calibration tool comprising a vertical connection flat plate and a vertical plate, the upper surface of the flat plate being a horizontal reference surface, the vertical plate being fixed with a reference mirror perpendicular to the horizontal reference surface, the theodolite support comprising a ring-shaped bottom plate, a ring-shaped top plate, and a support rod vertically connecting the ring-shaped bottom plate and the ring-shaped top plate;

[0007] S2: installing the calibration tool at the front of the deck where the star tracker base is located, the normal direction of the reference mirror on the calibration tool being as perpendicular to the bow-stern direction as possible;

[0008] S3: calibration step

[0009] 1) In-dock azimuth calibration of the calibration tool: leveling the theodolite support, measuring the angle between the normal of the reference mirror on the calibration tool and true north and the angle between the bow-stern line reference and true north by using a gyro theodolite, the difference between the two angles being A1, and fine-tuning the calibration tool so that A1 is 90°±X″;

[0010] 2) In-dock horizontal calibration of the calibration tool

[0011] According to the measurement results of the ship horizontal reference surface, the horizontal value of the horizontal reference surface of the calibration tool is measured by using a level, and the calibration tool is fine-tuned or the horizontal reference surface is ground so that the difference between the two is less than Y″, X and Y being a positive number.

[0012] 3) Star tracker azimuth calibration

[0013] Leveling the theodolite support, a calibration mirror is arranged on the star tracker base, the normal direction of which is as parallel to the bow-stern direction as possible, and the angle between the normal of the reference mirror on the calibration tool and the normal of the calibration mirror on the star tracker base is measured by using a collimation theodolite, the difference between the two angles being A2, A3=A1-A2 being the fixed deviation of the star tracker azimuth from the ship bow-stern line reference, and the average of multiple measurement values is obtained by repeating the measurement multiple times.

[0014] 4) Star tracker mooring state horizontal calibration

[0015] A level is placed on the horizontal reference surface of the calibration tool and the horizontal calibration surface of the star tracker base, and the transverse difference B3 and the longitudinal difference C3 between the horizontal reference surface of the calibration tool and the horizontal calibration surface of the star tracker are measured and recorded by using a differential level, and the average of multiple measurement values is obtained by repeating the measurement multiple times; the longitudinal difference C3 is the angle between the horizontal calibration surface and the horizontal reference surface along the bow-stern direction, and the transverse difference B3 is the angle between the horizontal calibration surface and the horizontal reference surface along the direction perpendicular to the bow-stern direction.

[0016] Preferably, the optical calibration method further comprises a step S4:

[0017] Suppose that the X axis of the ship body coordinate system points to the starboard, the Y axis points to the bow of the ship, and the Z axis points upward according to the right-hand coordinate system, and the celestial navigation equipment also adopts the right-hand coordinate system, the installation misalignment angle between the two coordinate systems being the above calibration results B3, C3, A3, and the attitude matrix between the two coordinate systems being:

[0018]

[0019] The coordinate output of the celestial navigation device is converted into real coordinates in the ship body coordinate system in real time through the attitude matrix.

[0020] Preferably, the calculation process of the digital calibration method is as follows:

[0021] The ship main inertial navigation system is consistent with the ship reference calibration before the ship is launched, and the navigation and posture output of the ship main inertial navigation system represents the real bearing and horizontal reference of the ship after the ship is launched. The X axis of the ship main inertial navigation system points to the starboard, the Y axis points to the bow of the ship, and the Z axis points upward according to the right-hand coordinate system. The celestial navigation device also adopts the right-hand coordinate system, and the Euler angles ΔH, ΔP and ΔR between the two coordinate systems are obtained. Therefore, the attitude matrix between the two coordinate systems is

[0022]

[0023] The coordinate output of the celestial navigation device is converted into real coordinates in the ship body coordinate system in real time through the attitude matrix.

[0024] Preferably, the preparation work of the digital calibration method is as follows:

[0025] The ship is in a mooring condition; the main inertial navigation device installation calibration and single machine recovery are completed, and the mooring performance test is completed; the navigation system CAN network has been recovered; the celestial navigation device installation and single machine recovery are completed.

[0026] Preferably, the operation process of the digital calibration method is as follows:

[0027] T1, the ship main inertial navigation device is normally aligned under the mooring condition, and is in a combined navigation state after navigation.

[0028] T2, the celestial navigation device is started and aligned for 4 hours.

[0029] T3, the software synchronously records the navigation and posture data information of the ship main inertial navigation device and the celestial navigation device.

[0030] T4, parameter correction: the Euler angles ΔH, ΔP and ΔR are calculated from the data of T3, and the attitude matrix is obtained.

[0031] As described above, the present application provides a calibration method of an astronomical navigation device, including an optical calibration method and a digital calibration method. The optical calibration method first calibrates the calibration tool with the ship reference, then calibrates the azimuth and levelness of the star tracker base with the calibration tool, and finally corrects the calibration deviation to unify the output information of the astronomical navigation with the real state of the ship. The digital calibration method synchronously records the ship main inertial navigation and the astronomical navigation device attitude data, calculates the attitude deviation angle of the two devices through software, and binds the angle to the astronomical navigation device to realize the unification of the astronomical navigation device and the ship reference. The calibration method of the present application fills the gap of the floating state calibration and digital calibration method of the ship technology-based laser gyro astronomical navigation device in the market, provides a floating state calibration and digital calibration method of the ship astronomical navigation device, solves the problem of detecting and correcting the zero position unification of high-precision devices under the condition and engineering environment, and to some extent, provides a means to increase the information output of the ship navigation system. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 The structure of the calibration tool of the present application is shown.

[0033] Figure 2 The structure of the theodolite support of the present application is shown.

[0034] Figure 3 The azimuth arrangement of the calibration tool of the present application is shown.

[0035] Figure 4 The calibration of the calibration tool and the bow / stern line is shown.

[0036] Figure 5 The azimuth calibration of the star tracker base and the calibration tool is shown.

[0037] Figure 6 The level calibration of the star tracker base and the calibration tool is shown.

[0038] Figure 7 The conversion of the coordinate system of the astronomical navigation device and the coordinate system of the ship is shown.

[0039] ELEMENT NUMBER EXPLANATION

[0040] 1 reference mirror

[0041] 3 adjusting screw

[0042] 4 calibration tool

[0043] 5 leveling bolt

[0044] 61 annular bottom plate

[0045] 62 annular top plate

[0046] 63 support rod

[0047] 2 star tracker base

[0048] 21 collimating mirror DETAILED DESCRIPTION

[0049] Those skilled in the art will readily understand other aspects and advantages of the application from the foregoing detailed description of the application. The application can be practiced with additional or different specific embodiments, and with variations of the disclosed embodiments, without departing from the spirit and scope of the application.

[0050] In the detailed description of embodiments of the application, reference is made to the accompanying drawings, which form a part thereof, and in which are shown by way of illustration various embodiments for practicing the application. The drawings are not necessarily to scale, the emphasis being placed rather upon the principles of the application. In the drawings:

[0051] For the purposes of the description hereinafter, the terms "upper", "lower", "right", "left", "rear", "front", "vertical", "horizontal", and derivatives thereof shall relate to the application as it is oriented in use or operation. The terms "on", "under", "below" and "above" as used herein refer to the relative positions of elements in the drawings. As used herein, the term "exemplary" means "an example of." The terms "coupled" and "coupling" as used herein refer to an electrical, mechanical, or fluidic connection between elements, with the term "directly coupled" or "directly connected" indicating that no intervening elements are present.

[0052] In the context of this application, a structure described as being "on" another structure can comprise embodiments where the two structures are in direct contact, or where additional structures are present between the two structures, such that the two structures are not in direct contact.

[0053] It is to be understood that the above-referenced elements of the specifically described embodiments are merely exemplary of the components that can be employed in practicing the application. Accordingly, it will be readily understood by those skilled in the art that other components not specifically disclosed can be employed without departing from the spirit and scope of the present application. It is also to be understood that the specific embodiments described herein are merely exemplary of the application and are not meant to limit the scope of the application as set forth in the following claims.

[0054] The present application provides a method for calibrating an astronomical navigation device, including an optical calibration method and a digital calibration method, wherein the optical calibration method comprises the following steps:

[0055] S1: providing an auxiliary tool, the auxiliary tool comprising a calibration tool 4 and a theodolite support, as shown in Figure 1 The calibration tool comprises a vertical connection flat plate and a vertical plate, the upper surface of the flat plate is a horizontal reference surface, the vertical plate is fixed with a reference (reflection) mirror 1 perpendicular to the horizontal reference surface, and the bottom plate is provided with an adjusting screw 3 to adjust the level. Figure 2 The theodolite support comprises a ring-shaped bottom plate 61, a ring-shaped top plate 62, and a support rod 63 vertically connecting the ring-shaped bottom plate 61 and the ring-shaped top plate 62; the theodolite support can be used to support a gyro theodolite and a deck theodolite, the ring-shaped bottom plate 61 is provided with three-point leveling bolts 5, and the center height of the theodolite support sighting mirror after the theodolite is installed on the theodolite support is 665mm.

[0056] S2: installing the calibration tool 4 in front of the deck where the star tracker base 2 is located, as shown in Figure 3 The distance between the calibration tool 4 and the center of the star tracker base 2 along the bow-stern direction is L1, and the distance between the calibration tool 4 and the center of the star tracker base 2 along the vertical bow-stern direction is L2, wherein L1 and L2 are 1.5m-3.0m, and the installation position is based on the principle of no obstruction to the view angle. The normal direction of the reference mirror 1 on the calibration tool 4 is as perpendicular to the bow-stern direction as possible.

[0057] Specifically, the calibration tool is arranged on the deck through a calibration tool installation base, the length x width x height of the calibration tool installation base is 330mm x 310mm x 50mm, and the flatness of the installation surface and the ship reference surface is less than N', that is, it is as parallel to the ship reference surface as possible.

[0058] S3: calibration steps

[0059] (1) In-dock azimuth calibration of the calibration tool

[0060] The theodolite support is leveled, and the gyro theodolite is used to measure the normal line of the reference mirror 1 on the calibration tool 4 and the angle between the ship bow-stern line reference and true north, and the difference between the two angles is A1, as shown in Figure 4 According to the measurement results, the calibration tool 4 is fine-tuned so that A1 is 90°(±X″). Through this step, it is ensured that the normal line of the reference mirror 1 is perpendicular to the bow-stern line.

[0061] (2) In-dock horizontal calibration of the calibration tool

[0062] According to the measurement results of the ship horizontal reference surface, the horizontal value of the horizontal reference surface of the calibration tool 4 is measured by using a level, and the calibration tool or the horizontal reference surface is fine-tuned or ground so that the difference between them is less than Y″. It should be understood that the values of X and Y here are determined according to the accuracy requirements on site, that is, the angle deviation is controlled to be in seconds. Through this step, it is ensured that the horizontal reference surface of the calibration tool is parallel to the ship horizontal reference surface.

[0063] (3) Azimuth calibration of star tracker

[0064] Under relatively stable conditions on the ship platform and in suitable environmental conditions, the theodolite support is leveled, such as... Figure 5 As shown, a calibration mirror 21 with its normal direction as parallel as possible to the bow and stern lines is installed on the celestial tracker base 2. The angle between the normal of the reference mirror 1 on the calibration fixture and the normal of the calibration mirror 21 on the celestial tracker base is measured using an autocollimating theodolite. The angle difference is A2. A3 = A1 - A2 is the fixed deviation between the celestial tracker's azimuth and the ship's bow and stern line reference. The measurement is repeated multiple times, and the average value A3 of each measurement is calculated.

[0065] (4) Level calibration of star tracker mooring status

[0066] A level 10 is placed on the horizontal reference plane of the calibration fixture and the horizontal calibration plane of the star tracker base. The horizontal calibration plane of the star tracker base can be understood as its upper surface. Figure 6 As shown, a differential level is used to simultaneously measure and record the lateral difference B3 and the longitudinal difference C3 between the horizontal reference plane of the calibration fixture and the horizontal calibration plane of the satellite tracker. Multiple consecutive measurements are performed, and the average value of each measurement is calculated. B3 and C3 represent the horizontal calibration deviation of the satellite tracker. The longitudinal difference C3 is the angle between the horizontal calibration plane and the horizontal reference plane along the bow-stern direction; the lateral difference B3 is the angle between the horizontal calibration plane and the horizontal reference plane along the perpendicular bow-stern direction.

[0067] S4: Correction calculation for calibration results

[0068] A3, B3, and C3 represent the calibration deviations between the heading and level of the celestial navigation equipment and the ship's reference. These deviations can be corrected by configuring parameters in the celestial navigation equipment through software, thereby unifying the celestial navigation output information with the ship's actual condition.

[0069] The calibration results adopt the physical meaning of software parameter correction. There are two ways to process the calibration results: hardware adjustment and software adjustment. Their purpose and physical meaning are the same.

[0070] Assuming the ship's coordinate system has the X-axis pointing to starboard, the Y-axis pointing to the bow, and the Z-axis pointing upwards according to a right-handed coordinate system, and the celestial navigation equipment also uses a right-handed coordinate system, the installation misalignment angles between the two coordinate systems are the calibration results B3, C3, and A3 mentioned above. The attitude matrix between the two coordinate systems is...

[0071]

[0072] The software adjustment of the calibration result is to convert the output of one coordinate system into the output of another coordinate system in real time through the attitude matrix, and the hardware adjustment of the calibration result is to adjust the device so that B3, C3 and A3 are less than a certain value, so that the above matrix is approximately a unit matrix. The physical meaning between the two is the same, the software correction is more accurate and universally applicable, and the hardware adjustment is a special case of the software correction.

[0073] The above process introduces the optical calibration method, and the following introduces the digital calibration method:

[0074] The digital calibration of the celestial navigation device is a calibration method that synchronously records the ship's master inertial navigation (master inertial navigation device) and celestial navigation device under the platform mooring condition, calculates the attitude deviation angle of the two devices through software, and binds it to the celestial navigation device to realize the unity of the celestial navigation device and the ship reference.

[0075] The error of the celestial navigation device gyro installed on the base makes the ideal azimuth and horizontal attitude of the celestial navigation device output coordinate system relative to the carrier (ship) coordinate system exist error, and the Euler angle between the two coordinate systems is ΔH, ΔP and ΔR. The actual performance is the angle between the celestial navigation device coordinate system (Oxcyczc) and the carrier (ship) coordinate system (Oxbybzb), as shown in Figure 7 .

[0076] The ship's master inertial navigation has been calibrated with the ship reference before the ship is launched, so the navigation and attitude output of the ship's master inertial navigation after launching represents the ship's azimuth and horizontal reference. The X-axis of the ship's master inertial navigation coordinate system points to the starboard, the Y-axis points to the bow of the ship, and the Z-axis points upward according to the right-hand coordinate system. The celestial navigation device also uses the right-hand coordinate system, and the Euler angle between the two coordinate systems is ΔH, ΔP and ΔR. Therefore, the attitude matrix between the two coordinate systems is

[0077]

[0078] The calibration is to find the Euler angle ΔH, ΔP and ΔR between the two coordinate systems, and input the Euler angle parameters into the configuration parameters of the celestial navigation device. The software of the celestial navigation device can make the device output consistent with the ship reference according to the configuration parameters. The software correction is more accurate and universally applicable, and is easy to operate.

[0079] Further, the pre-preparation conditions of the digital calibration method are:

[0080] The ship is in mooring condition; the master inertial navigation device installation calibration and single machine recovery are completed, and the mooring performance test is completed; the navigation system CAN network has been recovered; the celestial navigation device installation and single machine recovery are completed.

[0081] The specific process of the digital calibration method is:

[0082] The astronomical navigation device calibration needs to measure the horizontal attitude and the true value of the ship heading first, which are provided by the master inertial navigation system on the ship, and the operation flow of the digital calibration of the astronomical navigation device and the ship reference is as follows:

[0083] 1. The ship master inertial navigation device is normally aligned under the mooring condition, and is in the combined navigation state after the navigation.

[0084] 2. The astronomical navigation device is started and aligned for 4 hours.

[0085] 3. The ship master inertial navigation and the astronomical navigation device attitude data information are synchronously recorded by the software.

[0086] 4. Parameter correction: the Euler angles ΔH, ΔP and ΔR are calculated from the above data, and the Euler angles are bound to the configuration parameters of the astronomical navigation device to realize the correction. The heading information and the pitch and roll information output by the software corrected astronomical navigation device are within the deviation of the ship master inertial navigation heading and the pitch and roll, and the deviation is M" (as close to 0" as possible) to meet the calibration requirements.

[0087] In summary, the calibration method of the astronomical navigation device provided by the application includes the optical calibration method and the digital calibration method. The optical calibration method first calibrates the calibration tool with the ship reference, then calibrates the azimuth and the levelness of the star tracker base with the calibration tool, and finally corrects according to the calibration deviation to unify the astronomical navigation output information and the real state of the ship. The digital calibration method synchronously records the ship master inertial navigation and the astronomical navigation device attitude data, calculates the attitude deviation angle of the two devices by the software, and binds to the astronomical navigation device to realize the unification of the astronomical navigation device and the ship reference. The calibration method of the application fills the gap of the floating state calibration and the digital calibration method of the ship technology based on the laser gyro in the market, provides a floating state calibration and a digital calibration method of the ship astronomical navigation device, solves the problem of detecting and correcting the zero position unification of the high-precision device under the condition and the engineering environment, and to some extent, provides the means of increasing the information output device of the ship navigation system.

[0088] The above embodiments only exemplarily illustrate the principles and effects of the application, and are not used to limit the application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the application. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought disclosed by the application should be covered by the claims of the application.

Claims

1. A calibration method for an astronomical navigation device, characterized in that, This includes optical calibration methods and digital calibration methods. The optical calibration method includes the following steps: S1: Provide auxiliary tooling, which includes calibration tooling and theodolite support. The calibration tooling includes a vertically connected flat plate and a vertical plate. The upper surface of the flat plate is a horizontal reference plane. The vertical plate is fixed with a reference mirror perpendicular to the horizontal reference plane. The theodolite support includes an annular base plate, an annular top plate, and a support rod that vertically connects the annular base plate and the annular top plate. S2: Install the calibration fixture in front of the deck where the star tracker base is located, and make the normal direction of the reference mirror on the calibration fixture as perpendicular as possible to the bow-stern direction; S3: Calibration Steps 1) Calibration of the calibrator in the dock: Level the theodolite support, and use a gyro theodolite to measure the angle between the normal of the reference mirror on the calibration fixture and true north, and the angle between the ship's bow and stern reference and true north. The difference between the two angles is A1. Fine-tune the calibration fixture so that A1 is 90°±X″. 2) Leveling calibration within the tooling dock Based on the measurement results of the ship's horizontal reference plane, use a level to measure the horizontal value of the horizontal reference plane of the calibration tool, and fine-tune the calibration tool or grind the horizontal reference plane so that the difference between the two is less than Y″, where X and Y are positive numbers. 3) Azimuth calibration of celestial tracker Level the theodolite support. A calibration mirror with its normal direction as parallel as possible to the bow-stern line is placed on the star tracker base. The angle between the normal of the reference mirror on the calibration fixture and the normal of the calibration mirror on the star tracker base is measured using an autocollimating theodolite. This angle is valued as A2. A3 = A1 - A2 represents the fixed deviation between the star tracker's azimuth and the ship's bow-stern line reference. Repeat the measurement multiple times and calculate the average of the measured values. 4) Horizontal calibration of the star tracker's mooring status A level is placed on the horizontal reference plane of the calibration fixture and the horizontal calibration plane of the star tracker base. A differential level is used to simultaneously measure and record the lateral difference B3 and the longitudinal difference C3 between the horizontal reference plane of the calibration fixture and the horizontal calibration plane of the star tracker. The measurement is repeated multiple times, and the average value of each measurement is calculated. The longitudinal difference C3 is the angle between the horizontal calibration plane and the horizontal reference plane along the bow-stern direction; the lateral difference B3 is the angle between the horizontal calibration plane and the horizontal reference plane along the perpendicular bow-stern direction.

2. The calibration method for astronomical navigation equipment according to claim 1, characterized in that, The optical calibration method also includes step S4: Assuming the ship's coordinate system has the X-axis pointing to starboard, the Y-axis pointing to the bow, and the Z-axis pointing upwards according to the right-hand coordinate system, and the celestial navigation equipment also uses a right-hand coordinate system, the installation misalignment angles between the two coordinate systems are the calibration results B3, C3, and A3 mentioned above, and the attitude matrix between the two coordinate systems is: The coordinate output of the astronomical navigation equipment is converted into the actual coordinates in the ship's body coordinate system in real time using the attitude matrix.

3. The calibration method for astronomical navigation equipment according to claim 1, characterized in that, The calculation process for the digital calibration method is as follows: Before launching, the ship's main inertial navigation system (INS) was calibrated to the ship's reference standard. After launching, the attitude output of the INS represents the ship's true bearing and horizontal reference. The INS coordinate system's X-axis points to starboard, the Y-axis points to the bow, and the Z-axis points upward according to the right-hand coordinate system. The celestial navigation equipment also uses a right-hand coordinate system. The Euler angles ΔH, ΔP, and ΔR between the two coordinate systems are given. Therefore, the attitude matrix between the two coordinate systems is... The coordinate output of the astronomical navigation equipment is converted into coordinates in the main inertial navigation coordinate system in real time through the attitude matrix, thus representing the true coordinates in the ship's body coordinate system.

4. The calibration method for astronomical navigation equipment according to claim 3, characterized in that, The preparatory work for the digital calibration method is as follows: The vessel is in mooring condition; the main inertial navigation system has been installed, calibrated, and its individual units have been restored, and the mooring performance test has been completed; the navigation system's CAN network has been restored; and the installation and individual unit restoration of the astronomical navigation equipment have been completed.

5. The calibration method for astronomical navigation equipment according to claim 3, characterized in that, The workflow for digital calibration is as follows: T1. Under mooring conditions, the ship's main inertial navigation equipment is normally aligned and enters the combined navigation state after switching to navigation. T2. The astronomical navigation equipment is turned on and aligned for 4 hours. T3. The software simultaneously records the ship's main inertial navigation and astronomical navigation equipment's attitude and bearing data. T4, Parameter Correction: Euler angles ΔH, ΔP, and ΔR are calculated from the data in T3 to obtain the attitude matrix.

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