Method and device for calibrating course angle deviation of phase center and geometric center of short baseline

Abstract

The invention discloses a course angle deviation calibration method and device of a short baseline phase center and a geometric center, and belongs to the technical field of satellite navigation positioning. Wherein the GNSS receiver receives original RTCM observation data of the two antennas, solves a baseline vector formed by the two antennas based on a carrier phase difference technology, further solves a course angle formed by a connecting line of phase centers of the master antenna and the slave antenna, and performs differential calculation with the master antenna according to received RTCM data of a thousand-seeking base station to obtain speed and position information of the master antenna; and fusing the position, the speed and the attitude calculated by the IMU with the speed and the position of the antenna calculated by the GNSS to obtain a high-precision course angle formed by a connecting line of geometric centers of the master antenna and the slave antenna. A convenient and reliable course angle deviation calibration method is provided, the course angle between the two antennas is accurately calculated through fusion of a global navigation satellite system (GNSS) and an inertial measurement unit (IMU), and course angle errors caused by deviation of a phase center and a geometric center are corrected.

Description

Technical Field

[0001] The present application belongs to the field of satellite navigation and positioning technology, and in particular to a method and device for calibrating a heading angle deviation between a short baseline phase center and a geometric center. Background Art

[0002] With the rapid development of global navigation satellite system (GNSS) technology, GNSS has become the core equipment for modern surveying, navigation and positioning. GNSS receives satellite signals and calculates the position, speed, time and other information of the receiver. In some application scenarios, such as short baseline orientation technology, it is necessary to accurately measure the relative position and heading angle between two antennas.

[0003] Traditional GNSS technology mainly relies on carrier phase differential technology to solve the baseline vector and then calculate the heading angle. However, due to the deviation between the antenna phase center and the geometric center, this deviation is particularly significant in short baseline applications and may lead to significant errors in the heading angle. Summary of the invention

[0004] In order to solve the problems existing in the prior art in the above-mentioned background technology, the present application provides a method and device for calibrating the heading angle deviation between the short baseline phase center and the geometric center, which can significantly improve the heading angle measurement accuracy in the short baseline orientation technology, especially when there is a deviation between the phase center and the geometric center, and can correct such deviation to meet the needs of high-precision navigation and positioning.

[0005] The technical solution is as follows:

[0006] On the one hand, a method for calibrating a heading angle deviation between a short baseline phase center and a geometric center is provided, comprising:

[0007] The GNSS receiver receives the original RTCM observation data from the main antenna and the slave antenna; the baseline vector formed by the main antenna and the slave antenna is solved based on the carrier phase difference technology, and the heading angle formed by the line connecting the phase centers of the main antenna and the slave antenna is calculated through the baseline vector calculation. Based on the RTCM data received from the Qianxun base station, the main antenna is differentially calculated to obtain the speed and position information of the main antenna;

[0008] The position, speed, and attitude calculated by the IMU inertial measurement unit are fused with the speed and position of the antenna solved by GNSS, and the heading angle formed by the geometric center line of the master and slave antennas is calculated through the fused data.

[0009] As a further technical solution, the GNSS receiver receives the original RTCM observation data from the master antenna and the slave antenna, and uses real-time kinematic measurement RTK to solve the baseline vector formed by the two antennas.

[0010] In a further technical solution, the GNSS receiver obtains the baseline vector (Δx 12 ,Δy 12 ,Δz 12 ), get the relative position between the ECEF coordinate system, use the rotation matrix to convert the coordinates to the local horizontal coordinate system, the navigation coordinate system is selected as the northeast sky coordinate system, and the rotation matrix from the ECEF coordinate system to the n system is as follows:

[0011]

[0012] Among them, L and λ represent the latitude and longitude of the geographic coordinate system respectively. Then, the coordinates of the baseline vector in the northeast sky coordinate system are calculated as:

[0013]

[0014] Among them, b n =[ΔEΔNΔU], x e =(Δx 12 ,Δy 12 ,Δz 12 ), calculate the heading angle and elevation angle between the master and slave antennas according to the baseline vector in the northeast sky direction:

[0015]

[0016] A further technical solution is to filter the heading angle formed by the line connecting the phase centers of the main antenna and the slave antenna. The filtering method uses a sliding window average, and the static heading solution after filtering is calculated according to the following formula:

[0017]

[0018] Wherein, N is the selected window length, which is set to 10, and yaw(k) represents the filtered solution of the current heading result.

[0019] In a further technical solution, the specific steps of forming a heading angle by connecting the geometric centers of the master and slave antennas include:

[0020] Calibrate the inertial measurement unit IMU through a rotating device;

[0021] Use a level to align the IMU coordinate system with the IMU housing reference plane;

[0022] Install the whole device on the rotating device and move it according to the set process;

[0023] Using the GNSS / IMU fusion estimation algorithm, the deviation of the antenna phase center of the GNSS structure pole relative to the geometric center is estimated.

[0024] A further technical solution uses a GNSS / IMU fusion estimation algorithm to estimate the deviation of the GNSS antenna phase center relative to the geometric center. The specific steps are as follows:

[0025] The strapdown inertial guidance numerical update algorithm is used to calculate the attitude, velocity, and position based on the acceleration and angular velocity information output by the IMU. The quaternion is used to calculate the attitude of the IMU. The attitude equation is written as follows:

[0026]

[0027] Where q = [q0 q1 q2 q3] T , ω x ,ω y ,ω z is the three-axis angular velocity output of the gyroscope;

[0028] The quaternion is further converted into a direction cosine matrix:

[0029]

[0030] According to the above formula, the heading angle calculated by IMU can be obtained as:

[0031] The pitch angle is: The roll angle is:

[0032] The differential equation for velocity can be written as follows:

[0033]

[0034] in, is the acceleration of the IMU relative to the earth, is the velocity of the IMU relative to the Earth, is the vector of the specific force output by the IMU in the geographic coordinate system, Integrate the angular velocity of the earth to get the current velocity Vi relative to the earth, is the angular velocity of the geographic coordinate system relative to the earth coordinate system, is the gravitational acceleration vector. Integrating the formula twice can obtain the position information of the carrier, which can be written as follows:

[0035]

[0036] Where Δt is the time interval, V N,i 、V E,i are the north and east velocities at time i; R is the radius of curvature of the earth, and h is the height of the ellipsoid;

[0037] The error state equation of GNSS / IMU fusion is established, and the state space model of Kalman filtering is expressed as follows:

[0038] State one-step prediction:

[0039] One-step forecast mean square error of state:

[0040] The error-based state quantity X is selected to have a total of 15 dimensions:

[0041] The state quantities are respectively expressed as the three-dimensional attitude angle error φ, velocity error δv, position error δp, gyro zero bias ε b , plus zero bias

[0042] Construct a Kalman filter and use GNSS to assist the INS positioning system. The difference between the position and velocity information of INS and GNSS is regarded as the observed error state. The observation vector is:

[0043] Z1=[v ins -v gnss ,p ins -p gnss ] T

[0044] The observation equation is: Z = Hx + V, where V represents the observation noise and H is the observation design matrix. I is a 3*3 identity matrix, O is a 3*3 zero matrix;

[0045] Filter gain:

[0046] State Estimation:

[0047] Variance estimation: P k =(IK k H k ) k / k-1 .

[0048] Further technical solutions,

[0049] Calibrate the inertial measurement unit IMU through the rotating device. The specific steps are as follows:

[0050] The error equation of the accelerometer is:

[0051]

[0052] Among them, a x , a y , az A is the input value of the added x, y, and z axes. x , A y , A z is the added three-axis measurement value, b ax 、b ay 、b az is the three-axis zero bias, K ax , K ay , K az is the scale factor of the x, y, and z axes, S axy , S axz , S ayx , S ayz , S azx , S azy Indicates the installation error between different axes. H is a 3×12 input matrix consisting of two parts, F and I. F is composed of the three-axis added value of the input, and I 3×3 is a 3×3 identity matrix, and x is the vector of parameters to be estimated.

[0053] On the other hand, a device for calibrating a heading angle deviation between a short baseline phase center and a geometric center is provided, comprising:

[0054] The GNSS receiver is connected to two quadrifilar antennas, a master antenna, a slave antenna, two antennas, a rotating device, a level ruler, two IMU sensors, a fiber optic inertial navigation system, a structural rod, a computer device, and a power supply; the two antennas are the master antenna and the slave antenna;

[0055] The GNSS receiver is connected to the main antenna and the slave antenna respectively. The heading solution result of the GNSS receiver is output and stored on the computer device. The line connecting the edge of the structural pole and the center of the reserved hole for the antenna is kept consistent and aligned with the line connecting the geometric centers of the two antennas. The structural pole and the rotating device remain fixedly connected. The antennas are fixedly connected to the structural pole. The x-axis of the IMU is aligned and fixed with the edge of the structural pole through a level ruler. The movement of the structural pole, IMU and antenna is controlled by rotating the rotating device.

[0056] According to a further technical solution, the rotating device is a non-magnetic turntable.

[0057] According to a further technical solution, the antenna is a four-arm helical antenna.

[0058] The technical solution includes at least the following technical effects:

[0059] The present application discloses a method and device for calibrating the heading angle deviation between the short baseline phase center and the geometric center, providing a convenient and reliable heading angle deviation calibration method, which accurately calculates the heading angle between the main antenna and the slave antenna through the fusion of the global navigation satellite system GNSS and the inertial measurement unit IMU, and corrects the heading angle error caused by the deviation between the phase center and the geometric center. The heading angle measurement accuracy in the short baseline orientation technology can be significantly improved, especially when there is a deviation between the phase center and the geometric center, the deviation can be corrected to meet the needs of high-precision navigation and positioning. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0061] Figure 1 A schematic diagram of the principle of a method for calibrating a heading angle deviation between a short baseline phase center and a geometric center provided in an embodiment of the present application;

[0062] Figure 2 A flow chart of a method for calibrating a heading angle deviation between a short baseline phase center and a geometric center provided in an embodiment of the present application;

[0063] Figure 3 Comparison diagram of heading deviation estimation between phase center and geometric center. DETAILED DESCRIPTION

[0064] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0065] Related term explanation:

[0066] GNSS is the abbreviation of Global Navigation Satellite System, which is a global satellite navigation system used to receive signals from multiple satellite constellations and calculate the current position, speed and time information.

[0067] IMU is the abbreviation of Inertial Measurement Unit, which includes a three-axis accelerometer and a three-axis gyroscope. The accelerometer is used to measure the linear acceleration of the carrier, while the gyroscope is used to measure the angular velocity of the carrier.

[0068] RTK is the abbreviation of Real-Time Kinematic, which is a measurement technology that uses carrier phase differential technology to achieve centimeter-level positioning accuracy through real-time data transmission between a base station and a mobile station.

[0069] ECEF (Earth-Centered, Earth-Fixed) coordinate system: It is a three-dimensional Cartesian coordinate system with the center of mass of the Earth as the origin, the X-axis pointing to the intersection of the prime meridian and the equator, the Y-axis in the equatorial plane, perpendicular to the X-axis, and the Z-axis pointing to the North Pole. The ECEF coordinate system is used to determine the absolute position of any point on the Earth.

[0070] n system (Navigation Coordinate System): The navigation coordinate system is the basic reference system of the inertial navigation algorithm, which is used to determine the position, speed and attitude of the moving object. It can be the ECEF coordinate system or the Northeastern Sky coordinate system ENU.

[0071] The Kalman filter is an efficient recursive algorithm for estimating the state of a dynamic system from a series of noisy measurements.

[0072] INS is the abbreviation of Inertial Navigation System, which is an autonomous navigation system that does not rely on external information and does not radiate energy to the outside.

[0073] The basic principle of mechanical choreography is to obtain the changes in the position, velocity and attitude of the carrier by integrating the specific force and angular velocity observations output by the INS's accelerometer and gyroscope.

[0074] The antenna phase center is defined as the center of the radiation field wavefront, which should coincide with the geometric center of the antenna. However, due to the antenna characteristics and mechanical processing, the wavefront will have slight fluctuations, so there is a certain deviation between the phase center and the geometric center, generally in the millimeter level. For a longer baseline, the deviation has very little effect on the dual antenna orientation, but for a short baseline, the deviation cannot be ignored. Taking a 60cm baseline as an example, the heading error caused by a 2mm deviation can reach a maximum of 0.4 degrees.

[0075] At present, the azimuth formed by the line connecting the phase centers of dual antennas is often measured using the GNSS direction finding system. This method has the characteristics of high accuracy and no attitude drift error. The specific implementation method is to configure two antennas and a solution board on the carrier, use the carrier phase differential measurement technology to solve the baseline vector, and then obtain the azimuth information of the carrier through coordinate transformation based on the baseline vector. If you want to solve the azimuth between the geometric center lines of the two antennas, it is impossible to achieve it by GNSS alone. The inertial navigation system has the characteristics of short-term high precision. The X-axis of the IMU inertial measurement unit is strictly aligned with the line connecting the geometric centers of the antennas. The angular velocity and acceleration information obtained by the gyroscope and accelerometer can be used to obtain position, speed, and attitude information through mechanical arrangement. The high-precision navigation information of the GNSS system is used as an external observation in combination with the Kalman filter method. The fusion estimation with the navigation information calculated by the INS can obtain the accurate azimuth formed by the line connecting the geometric centers, so that the heading angle deviation between the phase center and the geometric center can be determined to meet the calibration requirements for the heading angle deviation between the phase center and the geometric center in the short baseline application scenario.

[0076] Embodiment 1 provides a heading angle deviation calibration device for a short baseline phase center and a geometric center, including: a GNSS receiver connected to two four-arm helical antennas, a master antenna, a slave antenna, two antennas, a rotating device, a level ruler, two IMU sensors, a fiber optic inertial navigation, a structural rod, a computer device, and a power supply; the two antennas are a master antenna and a slave antenna;

[0077] The GNSS receiver is connected to the main antenna and the slave antenna respectively. The heading solution result of the GNSS receiver is output and stored on the computer device. The line connecting the edge of the structural pole and the center of the reserved hole for the antenna is kept consistent and aligned with the line connecting the geometric centers of the two antennas. The structural pole and the rotating device remain fixedly connected. The antennas are fixedly connected to the structural pole. The x-axis of the IMU is aligned and fixed with the edge of the structural pole through a level ruler. The movement of the structural pole, IMU and antenna is controlled by rotating the rotating device.

[0078] In this embodiment, the rotating device is a non-magnetic turntable, the antenna is a four-arm helical antenna, the heading solution result of the GNSS receiver is directly output and stored in the computer through the serial port, and the structural rod is strictly designed to ensure that the line connecting the edge of the structural rod and the center of the reserved hole of the antenna is consistent, and strictly aligned with the line connecting the geometric centers of the two antennas.

[0079] Embodiment 2, as Figure 2As shown, a heading angle deviation calibration method for a short baseline phase center and a geometric center is provided, including: a GNSS receiver receives original RTCM observation data of a main antenna and a slave antenna; based on a carrier phase difference technology, the speed and position of the antenna are calculated, and the baseline vector formed by the main antenna and the slave antenna is solved, and the heading angle formed by the line connecting the phase centers of the main antenna and the slave antenna is calculated through the baseline vector calculation, and according to the received RTCM data of the Qianxun base station, a differential calculation is performed with the main antenna to obtain the speed and position information of the main antenna; the position, speed, and attitude calculated by the IMU inertial measurement unit are fused with the speed and position of the antenna obtained by the GNSS solution, and the heading angle formed by the line connecting the geometric centers of the main and slave antennas is calculated through the fused data.

[0080] like Figure 3 As shown, the specific steps are as follows:

[0081] Step S1: The GNSS board can obtain the baseline vector (Δx 12 ,Δy 12 ,Δz 12 ), the relative position between the ECEF coordinate systems is obtained. The coordinates need to be converted to the local horizontal coordinate system using the rotation matrix. The navigation coordinate system is selected as the northeast sky coordinate system. The rotation matrix from the e system to the n system is written as follows:

[0082]

[0083] Among them, L and λ represent the latitude and longitude of the geographic coordinate system respectively, and then the coordinates of the baseline vector in the northeast sky coordinate system are calculated as:

[0084]

[0085] Among them, b n =[ΔE ΔN ΔU],x e =(Δx 12 ,Δy 12 ,Δz 12 ), the heading angle and elevation angle between the master and slave antennas can be calculated based on the baseline vector in the northeast sky direction:

[0086]

[0087] Step S2: Since the baseline distance is 60 cm, the baseline is short and the heading fluctuation is large, the heading angle formed by the phase center line obtained in 1) needs to be filtered. The filtering method uses the sliding window mean. The static heading solution after filtering is calculated according to the following formula:

[0088]

[0089] Where N is the selected window length, which is set to 10, and yaw(k) represents the filtered solution of the current heading result. Then the center value of all heading filtering solutions in the initial static period is used as the heading angle formed by the phase center line, and the center value is determined by taking the mean of the filtering solution. The above steps complete the determination of the heading angle of the phase center line of the master and slave antennas. The following steps will be used to complete the estimation of the heading angle of the geometric center line;

[0090] Step S3: Due to processing reasons, the three axes of the IMU are not actually orthogonal, and the fusion estimation algorithm requires that the three axes of the accelerometer and gyroscope be orthogonal to obtain accurate estimation results.

[0091] Therefore, the IMU needs to be calibrated in advance. The specific steps for calibrating the IMU using a turntable are as follows:

[0092] In the IMU error model, the error equations of the gyroscope and accelerometer are independent of each other and can be calibrated separately. Taking the accelerometer as an example, the error equation can be written as follows;

[0093]

[0094] Among them, a x , a y , a z A is the input value of the added x, y, and z axes. x , A y , A z is the added three-axis measurement value, b ax 、b ay 、b az is the three-axis zero bias, K ax , K ay , K az is the scale factor of the x, y, and z axes, S axy , S axz , S ayx , S ayz , S azx , S azy Indicates the installation error between different axes. H is a 3×12 input matrix. The input is the three-axis plus value, which consists of two parts, F and I. F is composed of the input three-axis plus value, and I 3×3 is a 3×3 unit matrix, x is the vector of the parameter to be estimated; the turntable is leveled to ensure that the horizontal plane of the turntable is parallel to the horizontal plane of the earth, the turntable is used to change the IMU acceleration input, and the estimated parameter x(K is constructed by rotating multiple positions ax , K ay …b az) is solved by the least square method to obtain the calibration parameters. The calibration parameters of the gyroscope can also be obtained according to the above principle.

[0095] Step S4: Use a level to align the IMU coordinate system with the IMU housing reference plane.

[0096] Step S5: Install the IMU on the GNSS structure pole, and use a level to align the IMU housing reference surface with the pole side reference.

[0097] Step S6: Install the whole on a non-magnetic turntable and move according to the set process. In order to improve the observability of the speed in the fusion algorithm, the following movement scheme is adopted:

[0098] Step S7: Pitch for 30 seconds, swing in the horizontal direction for 30 seconds, and rotate back and forth in two or three seconds. After each movement, it is necessary to remain still in the horizontal position for one minute. The amplitude and rotation speed should be as large as possible, and GNSS data and IMU raw data at multiple positions are collected.

[0099] Step S8: During this process, the GNSS / IMU fusion estimation algorithm is used to estimate the installation deviation of the GNSS antenna phase center relative to the IMU coordinate system. The specific calculation steps are as follows:

[0100] Step S801, using the strapdown inertial guidance numerical update algorithm to infer the attitude, velocity, and position based on the acceleration and angular velocity information output by the IMU, and using quaternions to calculate the attitude of the IMU. The attitude equation is written in the following form:

[0101]

[0102] Where q = [q0 q1 q2 q3] T , ω x ,ω y ,ω z is the three-axis angular velocity output of the gyroscope;

[0103] The quaternion is further converted into a direction cosine matrix:

[0104]

[0105] According to the above formula, the heading angle calculated by IMU can be obtained as:

[0106] The pitch angle is: The roll angle is:

[0107] The differential equation for velocity can be written as follows:

[0108]

[0109] in, is the acceleration of the IMU relative to the earth, is the velocity of the IMU relative to the Earth, is the vector of the specific force output by the IMU in the geographic coordinate system, Integrate the angular velocity of the earth to get the current velocity Vi relative to the earth, is the angular velocity of the geographic coordinate system relative to the earth coordinate system, is the gravitational acceleration vector. Integrating the formula twice can obtain the position information of the carrier, which can be written as follows:

[0110]

[0111] Where Δt is the time interval, V N,i 、V E,i are the north and east velocities at time i; R is the radius of curvature of the earth, and h is the height of the ellipsoid;

[0112] Step S802: Establish the error state equation of GNSS / IMU fusion. The state space model of Kalman filtering is expressed as follows:

[0113] State one-step prediction:

[0114] One-step forecast mean square error of state:

[0115] The error-based state quantity X is selected to have a total of 15 dimensions: The state quantities are respectively expressed as the three-dimensional attitude angle error φ, velocity error δv, position error δp, gyro zero bias ε b , plus zero bias

[0116] Construct a Kalman filter and use GNSS to assist the INS positioning system. The difference between the position and velocity information of INS and GNSS is regarded as the observed error state. The observation vector is:

[0117] Z1=[v ins -v gnss ,p ins -p gnss ] T

[0118] The observation equation is: Z = Hx + V, where V represents the observation noise and H is the observation design matrix. I is a 3*3 identity matrix, and O is a 3*3 zero matrix.

[0119] Filter gain:

[0120] State Estimation:

[0121] Variance estimation: P k =(IK k H k ) k / k-1

[0122] By adjusting the initial parameter P k , Q k , R k Adjustments are made and combined with the fusion estimation scheme described in 8 to obtain the optimal heading estimate. Since the IMU housing reference plane has been aligned in steps S4 and S5, the heading estimate is the heading angle of the line connecting the geometric centers of the antennas. The optimal estimate of the heading angle of the line connecting the phase centers is calculated by step S2, and then the deviation between the antenna phase center and the geometric center of the GNSS structure pole can be calculated based on the geometric transfer relationship.

[0123] like Figure 3 As shown, a fiber optic north finder is used to obtain a high-precision heading result of the pole edge by finding the north. The result is used as the result of the true value comparison fusion estimation algorithm. A high-precision orientation result can be obtained by the fiber optic north finder. The north-finding accuracy of the instrument used reaches 0.05°.

[0124] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the invention invented herein. The present application is intended to cover any modification, use or adaptation of the present application, which follows the general principles of the present application and includes common knowledge or customary techniques in the art that the present application has not invented. The specification and embodiments are intended to be exemplary only, and the true scope and spirit of the present application are indicated by the appended claims.

[0125] It should be understood that the present application is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A method for calibrating the heading angle deviation between the short baseline phase center and the geometric center, characterized in that: include: The GNSS receiver receives raw RTCM observation data from the master antenna and slave antenna; The baseline vector formed by the main antenna and the slave antenna is solved based on the carrier phase difference technology. The heading angle formed by the line connecting the phase centers of the main antenna and the slave antenna is calculated through the baseline vector calculation. According to the RTCM data received from the Qianxun base station, the speed and position information of the main antenna are obtained by differential calculation with the main antenna. The position, speed, and attitude calculated by the IMU inertial measurement unit are fused with the speed and position of the antenna solved by GNSS, and the heading angle formed by the geometric center line of the master and slave antennas is calculated through the fused data.

2. The calibration method according to claim 1, characterized in that: The GNSS receiver receives the original RTCM observation data of the master antenna and the slave antenna, and uses real-time kinematic measurement RTK to solve the baseline vector formed by the two antennas.

3. The heading angle deviation calibration method of the short baseline phase center and the geometric center according to claim 1 is characterized in that: The GNSS receiver obtains the baseline vector (Δx 12 ,Δy 12 ,Δz 12 ), get the relative position between the ECEF coordinate system, use the rotation matrix to convert the coordinates to the local horizontal coordinate system, the navigation coordinate system is selected as the northeast sky coordinate system, and the rotation matrix from the ECEF coordinate system to the n system is as follows: Among them, L and λ represent the latitude and longitude of the geographic coordinate system respectively. Then, the coordinates of the baseline vector in the northeast sky coordinate system are calculated as: Among them, b n =[ΔEΔNΔU], x e =(Δx 12 ,Δy 12 ,Δz 12 ), calculate the heading angle and elevation angle between the master and slave antennas according to the baseline vector in the northeast sky direction:

4. The method for calibrating the heading angle deviation between the short baseline phase center and the geometric center according to claim 3, characterized in that: The heading angle formed by the line connecting the phase centers of the main antenna and the slave antenna is filtered. The filtering method uses the sliding window average. The static heading solution after filtering is calculated according to the following formula: Wherein, N is the selected window length, which is set to 10, and yaw(k) represents the filtered solution of the current heading result.

5. The method for calibrating the heading angle deviation between the short baseline phase center and the geometric center according to claim 1, characterized in that: The specific steps of calculating the heading angle formed by the geometric center line of the master and slave antennas include: Calibrate the inertial measurement unit IMU through a rotating device; Use a level to align the IMU coordinate system with the IMU housing reference plane; Install the whole device on the rotating device and move it according to the set process; Using the GNSS / IMU fusion estimation algorithm, the deviation of the antenna phase center of the GNSS structure pole relative to the geometric center is estimated.

6. The method for calibrating the heading angle deviation between the short baseline phase center and the geometric center according to claim 5, characterized in that: Use the GNSS / IMU fusion estimation algorithm to estimate the deviation of the GNSS antenna phase center relative to the geometric center. The specific steps are as follows: The strapdown inertial guidance numerical update algorithm is used to calculate the attitude, velocity, and position based on the acceleration and angular velocity information output by the IMU. The quaternion is used to calculate the attitude of the IMU. The attitude equation is written as follows: Where q = [q0 q1 q2 q3] T , ω x ,ω y ,ω z is the three-axis angular velocity output of the gyroscope; The quaternion is further converted into a direction cosine matrix: According to the above formula, the heading angle calculated by IMU can be obtained as: The pitch angle is: The roll angle is: The differential equation for velocity can be written as follows: in, is the acceleration of the IMU relative to the earth, is the velocity of the IMU relative to the Earth, is the vector of the specific force output by the IMU in the geographic coordinate system, Integrate the angular velocity of the earth to get the current velocity Vi relative to the earth, is the angular velocity of the geographic coordinate system relative to the earth coordinate system, is the gravitational acceleration vector. Integrating the formula twice can obtain the position information of the carrier, which can be written as follows: Where Δt is the time interval, V N,i 、V E,i are the north and east velocities at time i; R is the radius of curvature of the earth, and h is the height of the ellipsoid; The error state equation of GNSS / IMU fusion is established, and the state space model of Kalman filtering is expressed as follows: State one-step prediction: One-step forecast mean square error of state: The error-based state quantity X is selected to have a total of 15 dimensions: The state quantities are respectively expressed as the three-dimensional attitude angle error φ, velocity error δv, position error δp, gyro zero bias ε b , plus zero bias Construct a Kalman filter and use GNSS to assist the INS positioning system. The difference between the position and velocity information of INS and GNSS is regarded as the observed error state. The observation vector is: Z1=[v ins -v gnss ,p ins -p gnss ] T The observation equation is: Z = Hx + V, where V represents the observation noise and H is the observation design matrix. I is a 3*3 identity matrix, O is a 3*3 zero matrix; Filter gain: State Estimation: Variance estimation: P k =(IK k H k ) k / k-1 .

7. The method for calibrating the heading angle deviation between the short baseline phase center and the geometric center according to claim 5, characterized in that: Calibrate the inertial measurement unit IMU through the rotating device. The specific steps are as follows: The error equation of the accelerometer is: Among them, a x , a y , a z A is the input value of the added x, y, and z axes. x , A y , A z is the added three-axis measurement value, b ax 、b ay 、b az is the three-axis zero bias, K ax , K ay , K az is the scale factor of the x, y, and z axes, S axy , S axz , S ayx , S ayz , S azx , S azy Indicates the installation error between different axes. H is a 3×12 input matrix consisting of two parts, F and I. F is composed of the three-axis added value of the input, and I 3×3 is a 3×3 identity matrix, and x is the vector of parameters to be estimated.

8. A heading angle deviation calibration device for a short baseline phase center and a geometric center, using the heading angle deviation calibration method for a short baseline phase center and a geometric center according to any one of claims 1 to 7, characterized in that: include: The GNSS receiver is connected to two quadrifilar antennas, a master antenna, a slave antenna, two antennas, a rotating device, a level ruler, two IMU sensors, a fiber optic inertial navigation system, a structural rod, a computer device, and a power supply; the two antennas are the master antenna and the slave antenna; The GNSS receiver is connected to the main antenna and the slave antenna respectively. The heading solution result of the GNSS receiver is output and stored on the computer device. The line connecting the edge of the structural pole and the center of the reserved hole for the antenna is kept consistent and aligned with the line connecting the geometric centers of the two antennas. The structural pole and the rotating device remain fixedly connected. The antennas are fixedly connected to the structural pole. The x-axis of the IMU is aligned and fixed with the edge of the structural pole through a level ruler. The movement of the structural pole, IMU and antenna is controlled by rotating the rotating device.

9. The device for calibrating the heading angle deviation of the short baseline phase center and the geometric center according to claim 8, characterized in that: The rotating device is a non-magnetic turntable.

10. The device for calibrating the heading angle deviation of the short baseline phase center and the geometric center according to claim 8, characterized in that: The antenna is a four-arm helical antenna.

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