Airborne radar calibration method and system based on POS system of fiber-optic gyroscope body

Abstract

This paper presents a method and system for calibrating airborne radar based on a fiber optic gyroscope-based POS system. Relating to the field of airborne radar detection technology, it aims to efficiently calibrate the error between the phase center of the radar antenna and the reference center of the POS system when the fiber optic gyroscope-based POS system cannot be aligned in a static environment. The method includes: In a static state, the radar antenna and reference POS are mounted on an antenna test frame in an open area. The roll and pitch angles of the radar antenna are adjusted, the reference POS is initialized, and its three-dimensional attitude is recorded. The attitude relationship between the two is obtained using a total station. In a dynamic test run, the test frame is fixed to the test vehicle. The high-precision POS and reference POS are powered on and initialized. The vehicle travels at a specified speed, and multiple sets of convergent attitude information are recorded. The data is processed to obtain the attitude relationship. Combining the two attitude relationships, the installation misalignment angle between the radar antenna and the high-precision POS is calculated, completing the calibration. This method can efficiently achieve accurate calibration of airborne radar, ensuring operational performance.

Description

Technical Field

[0001] This invention relates to the field of airborne radar detection technology, and specifically to an airborne radar calibration method and system based on a fiber optic gyroscope-based POS system. Background Technology

[0002] With the rapid development of modern airborne radar design technology, the demand for improving the target detection accuracy of airborne radar is also constantly increasing. High-precision motion parameter acquisition is a prerequisite for high-performance airborne radar detection. It requires accurate measurement of the position and attitude of the radar antenna phase center to enable high-precision motion error compensation and target localization. The Position and Orientation System (POS), as a sensor providing position and attitude references, is essential for acquiring motion parameters for airborne radar when equipped with a high-precision POS system.

[0003] Traditional inertial navigation systems based on carrier platforms can no longer meet the requirements for high positioning accuracy. A high-precision positioning and attitude determination system must be added. Considering the airborne operating environment and cost control, a high-precision, miniaturized, lightweight, and low-cost POS system is essential. Currently, inertial navigation systems mainly consist of three hardware components: an Inertial Measurement Unit (IMU), a satellite navigation system, and an information processing system. IMUs are further classified into fiber optic and laser types based on the gyroscope. Fiber optic gyroscopes offer advantages over laser gyroscopes, including simpler manufacturing, easier integration, longer lifespan, lower cost, and shorter response time. Looking at the future development trends of fiber optic and laser gyroscopes, with further advancements in fiber optic communication technology, the accuracy and miniaturization of fiber optic gyroscopes will be significantly improved. The integration of fiber optic gyroscope-based POS systems into airborne radars has become an inevitable trend.

[0004] However, fiber optic gyroscope-based POS systems cannot provide accurate attitude information in static environments, posing a significant challenge to calibrating the attitude error between the radar antenna phase center and the POS system's reference center in static ground conditions. Therefore, a calibration method specifically designed for fiber optic gyroscope POS systems is urgently needed to address this problem. Summary of the Invention

[0005] The technical problem to be solved by this invention is how to efficiently calibrate the error between the phase center of the airborne radar antenna and the reference center of the POS system when the fiber optic gyroscope-based POS system cannot be aligned in a static environment.

[0006] This invention solves the above-mentioned technical problems through the following technical means: an airborne radar calibration method for a POS system based on a fiber optic gyroscope, comprising:

[0007] S1. Measurement of the attitude relationship between the radar antenna and the reference POS under static conditions: The radar antenna and the reference POS are installed on the antenna test frame and placed in an open outdoor area. The roll and pitch angles of the radar antenna are leveled in two dimensions. The reference POS is initialized. The three-dimensional attitude output by the reference POS after the radar antenna is leveled is recorded to obtain the attitude relationship between the radar antenna and the reference POS.

[0008] S2. Dynamic vehicle to obtain the attitude relationship between high-precision POS and reference POS: Fix the antenna test frame on the test vehicle, power on the high-precision POS and reference POS, and after initialization, drive the vehicle at a specified speed to record multiple sets of attitude information of high-precision POS and reference POS after convergence; process the recorded data to obtain the attitude relationship between high-precision POS and reference POS.

[0009] S3. Calculate the positional relationship between the radar antenna and the high-precision POS: Based on the attitude relationship between the radar antenna and the reference POS obtained in step S1, and the attitude relationship between the high-precision POS and the reference POS obtained in step S2, the installation misalignment angle between the radar antenna and the high-precision POS is calculated by attitude matrix conversion, the real-time attitude angle of the radar antenna and the position of the phase center of the radar antenna are calculated, and the calibration of the radar antenna is completed.

[0010] This invention first measures the attitude relationship between the radar antenna and the reference POS under static conditions, then obtains the attitude relationship between the high-precision POS and the reference POS through dynamic trolley operation, and finally calculates the installation misalignment angle between the radar antenna and the high-precision POS by combining these two sets of attitude relationships to complete the calibration. This approach utilizes static measurement to ensure the convenience of obtaining the initial attitude relationship and the reliability of the basic data, while the dynamic trolley operation eliminates the limitations of dynamic calibration in fiber optic gyroscope-based POS systems. Furthermore, by transmitting the attitude relationship between the reference POS and the high-precision POS, it effectively improves the calibration accuracy of the radar antenna, better meeting the high-precision positioning requirements of radar and providing strong support for the accurate operation of airborne radar in complex environments.

[0011] Furthermore, the extraction of the attitude matrix and attitude angles of the high-precision POS is specifically as follows:

[0012] Using the Northeast-Eastern Sky Coordinate System as the geographic coordinate system, and assuming the elevation angle of the high-precision POS is... Horizontal roll angle is and heading angle The attitude matrix of a high-precision POS is then represented as:

[0013]

[0014] set up Attitude angles are extracted using the attitude matrix of a high-precision POS:

[0015] Then we have:

[0016]

[0017]

[0018] .

[0019] Furthermore, the specific steps for calculating the installation misalignment angle between the radar antenna and the high-precision POS using attitude matrix conversion are as follows:

[0020] If the pitch angle, roll angle, and heading angle of the phase center of the radar antenna are known, construct its attitude matrix;

[0021] The formula for calculating the attitude matrix of the installation misalignment angle between the radar antenna and the high-precision POS is:

[0022]

[0023] in, This is the attitude matrix for a high-precision POS. This is the attitude matrix of the phase center of the radar antenna.

[0024] Furthermore, the real-time attitude angle of the radar antenna is calculated as follows:

[0025] If the real-time attitude angle of the high-precision POS is known, the real-time attitude angle of the radar antenna can be obtained using the installation misalignment angle between the high-precision POS and the radar antenna:

[0026]

[0027] in, This is the attitude matrix for a high-precision POS. The attitude matrix is ​​the installation misalignment angle between the radar antenna and the high-precision POS, and then the three attitude angles of the radar antenna are calculated.

[0028] Furthermore, the formula for calculating the position of the radar antenna phase center is as follows:

[0029]

[0030] in, This refers to the lever arm value between the high-precision POS and the radar antenna. For high-precision POS positioning. , , R is the radius of the Earth's reference ellipsoid, and e is the Earth's ellipticity. The height output by the high-precision POS system.

[0031] This invention also provides an airborne radar calibration system based on a fiber optic gyroscope-based POS system, comprising:

[0032] The antenna attitude leveling and static measurement module is used to install the radar antenna and the reference POS on the antenna test frame and place them in an open outdoor area. It levels the radar antenna in two dimensions, roll angle and pitch angle, initializes the reference POS, records the three-dimensional attitude output by the reference POS after the radar antenna is leveled, and obtains the attitude relationship between the radar antenna and the reference POS.

[0033] The dynamic sports car test and data recording module is used to fix the antenna test frame on the test vehicle, power up the high-precision POS and reference POS, and after initialization, drive the vehicle at a specified speed to record multiple sets of attitude information of the high-precision POS and reference POS after convergence; process the recorded data to obtain the attitude relationship between the high-precision POS and reference POS.

[0034] The data processing and calibration result output module is used to calculate the installation misalignment angle between the radar antenna and the reference POS based on the attitude relationship between the radar antenna and the reference POS obtained by the antenna attitude leveling and static measurement module, and the attitude relationship between the high-precision POS and the reference POS obtained by the dynamic sports car test and data recording module. It also calculates the real-time attitude angle of the radar antenna and the position of the phase center of the radar antenna, thus completing the calibration of the radar antenna.

[0035] Furthermore, the extraction of the attitude matrix and attitude angles of the high-precision POS in the dynamic sports car testing and data recording module is specifically as follows:

[0036] Using the Northeast-Eastern Sky Coordinate System as the geographic coordinate system, and assuming the elevation angle of the high-precision POS is... Horizontal roll angle is and heading angle The attitude matrix of a high-precision POS is then represented as:

[0037]

[0038] set up Attitude angles are extracted using the attitude matrix of a high-precision POS:

[0039] Then we have:

[0040]

[0041]

[0042] .

[0043] Furthermore, the data processing and calibration result output module calculates the installation misalignment angle between the radar antenna and the high-precision POS through attitude matrix conversion, specifically as follows:

[0044] If the pitch angle, roll angle, and heading angle of the phase center of the radar antenna are known, construct its attitude matrix;

[0045] The formula for calculating the attitude matrix of the installation misalignment angle between the radar antenna and the high-precision POS is:

[0046]

[0047] in, This is the attitude matrix for a high-precision POS. This is the attitude matrix of the phase center of the radar antenna.

[0048] Furthermore, the real-time attitude angle of the radar antenna is calculated as follows:

[0049] If the real-time attitude angle of the high-precision POS is known, the real-time attitude angle of the radar antenna can be obtained using the installation misalignment angle between the high-precision POS and the radar antenna:

[0050]

[0051] in, This is the attitude matrix for a high-precision POS. The attitude matrix is ​​the installation misalignment angle between the radar antenna and the high-precision POS, and then the three attitude angles of the radar antenna are calculated.

[0052] Furthermore, the formula for calculating the position of the radar antenna phase center is as follows:

[0053]

[0054] in, This refers to the lever arm value between the high-precision POS and the radar antenna. For high-precision POS positioning.

[0055] , , R is the radius of the Earth's reference ellipsoid, and e is the Earth's ellipticity. The height output by the high-precision POS system.

[0056] The advantages of this invention are:

[0057] 1. This invention uses a total station to accurately establish a measurement coordinate system in an outdoor static environment and level the antenna to directly obtain a high-precision attitude reference between the radar antenna and the reference POS. This effectively avoids interference from complex electromagnetic environments, improves the measurement accuracy of installation errors to the arcsecond level, and provides a reliable basis for subsequent dynamic calibration.

[0058] 2. This invention excites the error source of the inertial measurement unit by dynamically running a vehicle and collects multiple sets of convergent attitude data between high-precision POS and reference POS, which solves the problem that static calibration cannot cover dynamic errors, improves the accuracy of dynamic attitude relationships, and is significantly better than traditional physical measurement methods.

[0059] 3. This invention combines static reference and dynamic data, and uses matrix operations to accurately calculate the installation misalignment angle between the radar antenna and the high-precision POS, thereby achieving high-precision error transmission calibration. It can solve the antenna attitude and phase center position in real time without disassembling the equipment, meeting the high-precision positioning requirements of airborne radar, while reducing calibration time and cost. Attached Figure Description

[0060] Figure 1 This is a flowchart of the airborne radar calibration method for a POS system based on a fiber optic gyroscope, according to Embodiment 1 of the present invention.

[0061] Figure 2 This is a basic schematic diagram of the airborne radar calibration system based on the fiber optic gyroscope POS system in Embodiment 2 of the present invention. Detailed Implementation

[0062] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, 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.

[0063] Example 1

[0064] like Figure 1 As shown, the airborne radar calibration method for a POS system based on a fiber optic gyroscope includes:

[0065] S1. Measurement of the attitude relationship between the radar antenna and the reference POS under static conditions: The radar antenna and the reference POS are installed on the antenna test frame and placed in an open outdoor area. The roll and pitch angles of the radar antenna are leveled. The reference POS is initialized. The three-dimensional attitude output by the reference POS after the radar antenna is leveled is recorded to obtain the attitude relationship between the radar antenna and the reference POS.

[0066] Specifically, in step S1, when measuring the attitude relationship between the radar antenna and the reference POS, a measurement coordinate system is established using a total station. This coordinate system is used to unify the high-precision POS coordinate system, the reference POS coordinate system, and the radar antenna coordinate system, so as to realize the conversion of attitude data under different equipment coordinate systems.

[0067] S2. Dynamic vehicle to obtain the attitude relationship between high-precision POS and reference POS: Fix the antenna test frame on the test vehicle, power on the high-precision POS and reference POS, and after initialization, drive the vehicle at a specified speed to record multiple sets of attitude information of high-precision POS and reference POS after convergence; process the recorded data to obtain the attitude relationship between high-precision POS and reference POS.

[0068] Specifically, the relative attitude angle between the high-precision POS and the reference POS is estimated in real time, which includes two stages: coarse alignment and fine alignment. In the coarse alignment stage, the received position and attitude information of the reference POS system is used as the initial navigation parameters for the high-precision POS to establish its initial attitude matrix and perform navigation calculations, preparing for the fine alignment stage. In the fine alignment stage, the difference in navigation parameters between the reference POS and the high-precision POS is used as measurement information and fed into a Kalman filter for filtering to accurately estimate the relative attitude angle between the high-precision POS and the reference POS. Further corrections are then made to establish an accurate initial transformation matrix, completing the initial alignment of the high-precision POS.

[0069] The specific extraction of the attitude matrix and attitude angles for high-precision POS is as follows:

[0070] Using the Northeast-Eastern Sky Coordinate System as the geographic coordinate system, and assuming the elevation angle of the high-precision POS is... Horizontal roll angle is and heading angle The attitude matrix of a high-precision POS is then represented as:

[0071]

[0072] set up Attitude angles are extracted using the attitude matrix of a high-precision POS:

[0073] Then we have:

[0074]

[0075]

[0076] .

[0077] S3. Calculate the positional relationship between the radar antenna and the high-precision POS: Based on the attitude relationship between the radar antenna and the reference POS obtained in step S1, and the attitude relationship between the high-precision POS and the reference POS obtained in step S2, the installation misalignment angle between the radar antenna and the high-precision POS is calculated by attitude matrix conversion, the real-time attitude angle of the radar antenna and the position of the phase center of the radar antenna are calculated, and the calibration of the radar antenna is completed.

[0078] Specifically, the installation misalignment angle between the radar antenna and the high-precision POS is calculated using the attitude matrix:

[0079] If the pitch angle, roll angle, and heading angle of the phase center of the radar antenna are known, construct its attitude matrix;

[0080] The formula for calculating the attitude matrix of the installation misalignment angle between the radar antenna and the high-precision POS is:

[0081]

[0082] in, This is the attitude matrix for a high-precision POS. This is the attitude matrix of the phase center of the radar antenna.

[0083] The real-time attitude angle of the radar antenna is calculated as follows:

[0084] If the real-time attitude angle of the high-precision POS is known, the real-time attitude angle of the radar antenna can be obtained using the installation misalignment angle between the high-precision POS and the radar antenna:

[0085]

[0086] in, This is the attitude matrix for a high-precision POS. The attitude matrix is ​​the installation misalignment angle between the radar antenna and the high-precision POS, and then the three attitude angles of the radar antenna are calculated.

[0087] The formula for calculating the position of the radar antenna phase center is as follows:

[0088]

[0089] in, The mast arm value between the high-precision POS and the radar antenna is calculated using the high-precision POS center coordinates and antenna center coordinates obtained from the initial calibration of the total station. For high-precision POS positioning. , , R is the radius of the Earth's reference ellipsoid, and e is the Earth's ellipticity. The height output by the high-precision POS system.

[0090] Example 2

[0091] Based on Embodiment 1, Embodiment 2 of the present invention also provides an airborne radar calibration system based on a fiber optic gyroscope-based POS system, including:

[0092] The antenna attitude leveling and static measurement module is used to install the radar antenna and the reference POS on the antenna test frame and place them in an open outdoor area. It levels the radar antenna in two dimensions, roll and pitch, initializes the reference POS, records the three-dimensional attitude output by the reference POS after the radar antenna is leveled, and obtains the attitude relationship between the radar antenna and the reference POS.

[0093] Specifically, when measuring the attitude relationship between the radar antenna and the reference POS, a measurement coordinate system is established using a total station. This coordinate system is used to unify the high-precision POS coordinate system, the reference POS coordinate system, and the radar antenna coordinate system, so as to realize the conversion of attitude data under different equipment coordinate systems.

[0094] The dynamic vehicle testing and data recording module is used to fix the antenna test frame on the test vehicle, power on the high-precision POS and reference POS, and after initialization, drive the vehicle at a specified speed to record multiple sets of attitude information after convergence of the high-precision POS and reference POS; process the recorded data to obtain the attitude relationship between the high-precision POS and reference POS. Figure 2 As shown.

[0095] Specifically, the high-precision POS attitude matrix and attitude angle extraction in the dynamic sports car testing and data recording module are as follows:

[0096] Using the Northeast-Eastern Sky Coordinate System as the geographic coordinate system, and assuming the elevation angle of the high-precision POS is... Horizontal roll angle is and heading angle The attitude matrix of a high-precision POS is then represented as:

[0097]

[0098] set up Attitude angles are extracted using the attitude matrix of a high-precision POS:

[0099] Then we have:

[0100]

[0101]

[0102] .

[0103] The data processing and calibration result output module is used to calculate the installation misalignment angle between the radar antenna and the reference POS based on the attitude relationship between the radar antenna and the reference POS obtained by the antenna attitude leveling and static measurement module, and the attitude relationship between the high-precision POS and the reference POS obtained by the dynamic sports car test and data recording module. It also calculates the real-time attitude angle of the radar antenna and the position of the phase center of the radar antenna, thus completing the calibration of the radar antenna.

[0104] Specifically, the data processing and calibration result output module calculates the installation misalignment angle between the radar antenna and the high-precision POS through attitude matrix conversion, including:

[0105] If the pitch angle, roll angle, and heading angle of the phase center of the radar antenna are known, construct its attitude matrix;

[0106] The formula for calculating the attitude matrix of the installation misalignment angle between the radar antenna and the high-precision POS is:

[0107]

[0108] in, This is the attitude matrix for a high-precision POS. This is the attitude matrix of the phase center of the radar antenna.

[0109] The real-time attitude angle of the radar antenna is calculated as follows:

[0110] If the real-time attitude angle of the high-precision POS is known, the real-time attitude angle of the radar antenna can be obtained using the installation misalignment angle between the high-precision POS and the radar antenna:

[0111]

[0112] in, This is the attitude matrix for a high-precision POS. The attitude matrix is ​​the installation misalignment angle between the radar antenna and the high-precision POS, and then the three attitude angles of the radar antenna are calculated.

[0113] The formula for calculating the position of the radar antenna phase center is as follows:

[0114]

[0115] in, The mast arm value between the high-precision POS and the radar antenna is calculated using the high-precision POS center coordinates and antenna center coordinates obtained from the initial calibration of the total station. For high-precision POS positioning.

[0116] , , R is the radius of the Earth's reference ellipsoid, and e is the Earth's ellipticity. The height output by the high-precision POS system.

[0117] 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. An airborne radar calibration method based on a fiber-optic gyroscope system POS, characterized in that, include: S1. Measurement of the attitude relationship between the radar antenna and the reference POS under static conditions: The radar antenna and the reference POS are installed on the antenna test frame and placed in an open outdoor area. The roll and pitch angles of the radar antenna are leveled in two dimensions. The reference POS is initialized. The three-dimensional attitude output by the reference POS after the radar antenna is leveled is recorded to obtain the attitude relationship between the radar antenna and the reference POS. S2. Dynamic vehicle acquisition of attitude relationship between high-precision POS and reference POS: The antenna test frame is fixed on the test vehicle, the high-precision POS and reference POS are powered on, and after initialization, the vehicle is driven at a specified speed, recording multiple sets of attitude information of the high-precision POS and reference POS after convergence; the recorded data is processed to obtain the attitude relationship between the high-precision POS and reference POS; wherein, the attitude matrix and attitude angle extraction of the high-precision POS are specifically as follows: Taking the northeast celestial coordinate system as the geographic coordinate system, assuming that the pitch angle of the high-precision POS is , the roll angle is , and the heading angle is , the attitude matrix of the high-precision POS is represented as: set up Attitude angles are extracted using the attitude matrix of a high-precision POS: Then we have: S3. Calculate the positional relationship between the radar antenna and the high-precision POS: Based on the attitude relationship between the radar antenna and the reference POS obtained in step S1, and the attitude relationship between the high-precision POS and the reference POS obtained in step S2, the installation misalignment angle between the radar antenna and the high-precision POS is calculated through attitude matrix conversion. The real-time attitude angle of the radar antenna and the position of the phase center of the radar antenna are calculated to complete the calibration of the radar antenna; wherein, the specific calculation of the installation misalignment angle between the radar antenna and the high-precision POS through attitude matrix conversion is as follows: If the pitch angle, roll angle, and heading angle of the phase center of the radar antenna are known, construct its attitude matrix; The formula for calculating the attitude matrix of the installation misalignment angle between the radar antenna and the high-precision POS is: in, This is the attitude matrix for a high-precision POS. The attitude matrix of the radar antenna phase center; The real-time attitude angle of the radar antenna is calculated as follows: If the real-time attitude angle of the high-precision POS is known, the real-time attitude angle of the radar antenna can be obtained using the installation misalignment angle between the high-precision POS and the radar antenna: in, This is the attitude matrix for a high-precision POS. The attitude matrix is ​​the installation misalignment angle between the radar antenna and the high-precision POS, and then the three attitude angles of the radar antenna are calculated.

2. The airborne radar calibration method for a POS system based on a fiber optic gyroscope as described in claim 1, characterized in that, The formula for calculating the position of the radar antenna phase center is as follows: in, This refers to the lever arm value between the high-precision POS and the radar antenna. For high-precision POS positioning. , , R is the radius of the Earth's reference ellipsoid, and e is the Earth's ellipticity. The height output by the high-precision POS system.

3. An airborne radar calibration system based on a fiber optic gyroscope-based POS system, characterized in that, include: The antenna attitude leveling and static measurement module is used to install the radar antenna and the reference POS on the antenna test frame and place them in an open outdoor area. It levels the radar antenna in two dimensions, roll angle and pitch angle, initializes the reference POS, records the three-dimensional attitude output by the reference POS after the radar antenna is leveled, and obtains the attitude relationship between the radar antenna and the reference POS. The dynamic sports car testing and data recording module is used to fix the antenna test frame on the test vehicle, power on the high-precision POS and reference POS, and after initialization, drive the vehicle at a specified speed to record multiple sets of attitude information of the high-precision POS and reference POS after convergence; process the recorded data to obtain the attitude relationship between the high-precision POS and reference POS; wherein, the attitude matrix and attitude angle extraction of the high-precision POS are specifically as follows: Using the Northeast-Eastern Sky Coordinate System as the geographic coordinate system, and assuming the elevation angle of the high-precision POS is... Horizontal roll angle is and heading angle The attitude matrix of a high-precision POS is then represented as: set up Attitude angles are extracted using the attitude matrix of a high-precision POS: Then we have: The data processing and calibration result output module is used to calculate the installation misalignment angle between the radar antenna and the reference POS based on the attitude relationship between the radar antenna and the reference POS obtained from the antenna attitude leveling and static measurement module, and the attitude relationship between the high-precision POS and the reference POS obtained from the dynamic sports car test and data recording module. It also calculates the real-time attitude angle and the position of the radar antenna phase center, thus completing the calibration of the radar antenna. Specifically, the calculation of the installation misalignment angle between the radar antenna and the high-precision POS using the attitude matrix conversion is as follows: If the pitch angle, roll angle, and heading angle of the phase center of the radar antenna are known, construct its attitude matrix; The formula for calculating the attitude matrix of the installation misalignment angle between the radar antenna and the high-precision POS is: in, This is the attitude matrix for a high-precision POS. The attitude matrix of the radar antenna phase center; The real-time attitude angle of the radar antenna is calculated as follows: If the real-time attitude angle of the high-precision POS is known, the real-time attitude angle of the radar antenna can be obtained using the installation misalignment angle between the high-precision POS and the radar antenna: in, This is the attitude matrix for a high-precision POS. The attitude matrix is ​​the installation misalignment angle between the radar antenna and the high-precision POS, and then the three attitude angles of the radar antenna are calculated.

4. The airborne radar calibration system based on a fiber optic gyroscope-based POS system according to claim 3, characterized in that, The formula for calculating the position of the radar antenna phase center is as follows: in, This refers to the lever arm value between the high-precision POS and the radar antenna. For high-precision POS positioning. , , R is the radius of the Earth's reference ellipsoid, and e is the Earth's ellipticity. The height output by the high-precision POS system.

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