A method and system for calibrating center-of-mass deviation of three-axis independent maneuvers of a gravity satellite

Abstract

The present invention relates to a method and system for calibrating the center of mass deviation of a gravity satellite during three-axis independent maneuvers, and specifically to the field of calibration technology. The method comprises: obtaining, while the satellite is performing a saturation magnetic torque operation of a magnetic torquer, the satellite's translational acceleration measured by an accelerometer and data measured by a star sensor when the satellite rotates around each axis in a three-axis independent rotation maneuver; sequentially performing differentiation and differential processing on the data measured by the star sensor during rotation to obtain the satellite's angular velocity and angular acceleration during rotation; performing least squares estimation based on the satellite's angular velocity, the satellite's angular acceleration, and the satellite's translational acceleration measured by the accelerometer during rotation to obtain an on-orbit calibration parameter for the satellite's center of mass deviation during rotation; and calibrating the satellite's center of mass deviation during rotation based on the on-orbit calibration parameter for the satellite's center of mass deviation. The present invention makes the obtained satellite center of mass deviation parameter more accurate.

Description

Technical Field

[0001] The present invention relates to the field of calibration technology, and in particular to a method and system for calibrating the center of mass deviation of a gravity satellite with three-axis independent maneuvers. Background Art

[0002] Satellites measuring Earth's gravity field include the CHAMP satellites for altitude tracking, the GRACE and GRACE Follow-on satellites for low-altitude satellite tracking, and the GOCE satellites for gravity gradient measurement. The GRACE satellite, launched in March 2002, carries a payload consisting of an onboard receiver, a microwave ranging system, an ultra-high-precision electrostatically suspended accelerometer, a star sensor, and a laser retroreflector.

[0003] High-precision electrostatically suspended accelerometers are the core payload of gravity satellites. Their function is to measure the acceleration caused by non-conservative forces acting on the satellite. Because there is an inevitable deviation between the accelerometer's mounting position on the satellite and the satellite's center of mass, satellite attitude rotation introduces centrifugal acceleration. The accelerometer itself cannot distinguish between the non-conservative forces acting on the satellite and the perturbation acceleration introduced by attitude rotation. To ensure that the measurement output primarily reflects the non-conservative forces, the relative position of the accelerometer proof mass and the satellite's center of mass must be controlled within a certain range so that the perturbation acceleration introduced by rotation does not affect the accuracy of non-conservative force measurements.

[0004] While a satellite is in orbit, due to the consumption of propellant, the satellite's center of mass will change relative to the satellite frame. The accelerometer and the satellite frame are approximately rigidly connected, so the accelerometer test mass and the actual position of the satellite's center of mass in orbit will change over time. This requires regular measurement of the center of mass position deviation between the two throughout the satellite's life cycle, and the use of the center of mass adjustment mechanism for on-orbit adjustment to control the deviation between the two within a certain range, thereby ensuring the generation of high-precision model products of the gravity satellite.

[0005] (1) The current calibration method of gravity satellite center of mass bias mostly adopts the continuous maneuvering of the three axes of the accelerometer in sequence, with a total maneuvering time of 300 seconds and a maneuvering time of 100 seconds for each axis. The effective maneuvering signal is short in duration. In the process of center of mass bias estimation, the low signal-to-noise ratio maneuvering signal can easily lead to the divergence of the center of mass bias estimation result. In addition, the continuous maneuvering of the three axes will cause crosstalk and coupling effects on the three axes of the accelerometer during the 300-second maneuvering time, resulting in large errors in the final satellite center of mass bias parameter. Summary of the Invention

[0006] The purpose of the present invention is to provide a method and system for calibrating the center of mass deviation of a gravity satellite with three-axis independent maneuvers, so that the obtained satellite center of mass deviation parameters are more accurate.

[0007] To achieve the above object, the present invention provides the following solutions:

[0008] A method for calibrating the center of mass deviation of a gravity satellite with three-axis independent maneuvers, comprising:

[0009] When the satellite is performing the saturation magnetic torque operation of the magnetorectron, the satellite translation acceleration measured by the accelerometer and the star sensor are respectively obtained when the satellite rotates around each axis in the three-axis independent rotation maneuver state;

[0010] For any one of the three axes, performing differentiation and difference processing on the data measured by the star sensor when rotating around the axis to obtain the satellite angular velocity and the satellite angular acceleration when rotating around the axis;

[0011] Obtaining an on-orbit calibration parameter of the satellite center of mass deviation when rotating around the axis by performing least square estimation based on the satellite angular velocity when rotating around the axis, the satellite angular acceleration when rotating around the axis, and the satellite translational acceleration measured by an accelerometer when rotating around the axis;

[0012] The center of mass deviation of the satellite rotating around the axis is calibrated according to the on-orbit calibration parameters of the center of mass deviation of the satellite rotating around the axis.

[0013] Optionally, the obtaining of an on-orbit calibration parameter of the satellite center of mass deviation when rotating around the axis by performing least squares estimation based on the satellite angular velocity when rotating around the axis, the satellite angular acceleration when rotating around the axis, and the satellite translational acceleration measured by an accelerometer when rotating around the axis specifically includes:

[0014] Obtaining a motion matrix when rotating around the axis according to the satellite angular velocity when rotating around the axis and the satellite angular acceleration when rotating around the axis;

[0015] The least squares estimation method is used to estimate the formula The on-orbit calibration parameters of the satellite center of mass deviation are obtained by processing, where Denotes the satellite centroid deviation using least squares The estimated value of represents the on-orbit calibration parameter of the satellite center of mass deviation, A represents the motion matrix, and A T represents the transpose of A, P represents the weight matrix, represents the satellite translational acceleration.

[0016] Optionally, before performing least squares estimation on the satellite angular velocity when rotating around the axis, the satellite angular acceleration when rotating around the axis, and the satellite translational acceleration measured by the accelerometer when rotating around the axis to obtain the on-orbit calibration parameter of the satellite center of mass deviation when rotating around the axis, the method further includes:

[0017] The satellite translation acceleration measured by the accelerometer when the satellite rotates around the axis is sequentially subjected to de-drift and de-biasing processing to obtain the processed satellite translation acceleration.

[0018] Optionally, obtaining a motion matrix when rotating around the axis according to the satellite angular velocity and the satellite angular acceleration when rotating around the axis specifically includes:

[0019] When rotating around the x-axis, the motion matrix is in, represents the satellite angular acceleration in the x direction, ω x Indicates the satellite angular velocity in the x direction;

[0020] When rotating around the y-axis, the motion matrix is represents the satellite angular acceleration in the y direction, ω y Indicates the satellite angular velocity in the y direction;

[0021] When rotating around the z-axis, the motion matrix is represents the satellite angular acceleration in the z direction, ω z Indicates the satellite's angular velocity in the z direction.

[0022] A mass center deviation calibration system for three-axis independent maneuvering of a gravity satellite, comprising:

[0023] An acquisition module is used to obtain the satellite translation acceleration measured by the accelerometer and the star sensor when the satellite rotates around each axis in a three-axis independent rotation maneuver state when the satellite performs the saturation magnetic torque operation of the magnetic torquer;

[0024] A differential processing module is used to sequentially perform differential and difference processing on the data measured by the star sensor when rotating around any one of the three axes to obtain the satellite angular velocity and the satellite angular acceleration when rotating around the axis;

[0025] a parameter determination module, configured to obtain an on-orbit calibration parameter of the satellite center of mass deviation when rotating around the axis by performing least squares estimation based on the satellite angular velocity when rotating around the axis, the satellite angular acceleration when rotating around the axis, and the satellite translational acceleration measured by an accelerometer when rotating around the axis;

[0026] The calibration module is used to calibrate the center of mass deviation of the satellite when it rotates around the axis according to the on-orbit calibration parameters of the satellite center of mass deviation when it rotates around the axis.

[0027] Optionally, the parameter determination module specifically includes:

[0028] a motion matrix calculation unit, configured to obtain a motion matrix when rotating around the axis according to the satellite angular velocity and the satellite angular acceleration when rotating around the axis;

[0029] Parameter determination unit, used to use the least squares estimation method to estimate the formula The on-orbit calibration parameters of the satellite center of mass deviation are obtained by processing, where Denotes the satellite centroid deviation using least squares The estimated value of represents the on-orbit calibration parameter of the satellite center of mass deviation, A represents the motion matrix, and A T represents the transpose of A, P represents the weight matrix, represents the satellite translational acceleration.

[0030] Optionally, the gravity satellite three-axis independent maneuvering center of mass deviation calibration system further includes:

[0031] The satellite translation acceleration measured by the accelerometer when the satellite rotates around the axis is sequentially subjected to de-drift and de-biasing processing to obtain the processed satellite translation acceleration.

[0032] Optionally, the motion matrix calculation unit specifically includes:

[0033] The x motion matrix calculation subunit is used for rotating around the x-axis. The motion matrix is in, represents the satellite angular acceleration in the x direction, ω x Indicates the satellite angular velocity in the x direction;

[0034] The y motion matrix calculation subunit is used for rotating around the y axis. The motion matrix is represents the satellite angular acceleration in the y direction, ω y Indicates the satellite angular velocity in the y direction;

[0035] The z motion matrix calculation subunit is used for rotating around the z axis. The motion matrix is represents the satellite angular acceleration in the z direction, ω z Indicates the satellite's angular velocity in the z direction.

[0036] According to the specific embodiment provided by the present invention, the present invention discloses the following technical effects: the present invention uses the satellite translational acceleration, angular velocity and angular acceleration measured by the accelerometer to realize the in-orbit calibration of the satellite center of mass deviation parameters through the least squares method, so that the obtained satellite center of mass deviation parameters are more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0038] Figure 1 A flow chart of a method for calibrating the center of mass deviation of a gravity satellite with three-axis independent maneuvers provided by an embodiment of the present invention;

[0039] Figure 2 This is the non-conservative force estimation curve for the gravity satellite;

[0040] Figure 3 This is the satellite angular velocity curve under square wave maneuvering conditions. DETAILED DESCRIPTION

[0041] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0042] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] As a high-precision measurement satellite, gravity satellites need to calibrate the deviation between the satellite's center of mass and the accelerometer center to ensure the accuracy of gravity field model products. During the normal orbit entry and stable operation of the satellite, the center of mass deviation will change significantly due to the influence of launch jitter, on-orbit fuel consumption, etc. The present invention designs a three-axis independent rotation maneuver of the satellite to generate rotational acceleration, uses the angular velocity obtained by the differentiation of the star sensor and the translational acceleration measured by the accelerometer, and obtains the on-orbit calibration result of the satellite center of mass deviation through least squares estimation, such as Figure 1 As shown, an embodiment of the present invention provides a method for calibrating the center of mass deviation of a gravity satellite for three-axis independent maneuvering, comprising:

[0044] When the satellite is operating with its magnetorectron saturation magnetic torque (the satellite uses a magnetorectron to drive its rotation without consuming its own fuel), the satellite's translational acceleration measured by the accelerometer and the star sensor are respectively obtained when the satellite rotates around each axis in a three-axis independent rotation maneuver, that is, a maneuver with a single-axis square wave excitation signal. Both the accelerometer and the star sensor are onboard payloads, and the data measured by the star sensor include the satellite's three-axis attitude angles (roll, pitch, and yaw).

[0045] For any one of the three axes, the data measured by the star sensor when rotating around the axis are sequentially differentiated and differentially processed to obtain the satellite angular velocity and the satellite angular acceleration when rotating around the axis.

[0046] An on-orbit calibration parameter of the satellite center of mass deviation when rotating around the axis is obtained by performing least square estimation based on the satellite angular velocity when rotating around the axis, the satellite angular acceleration when rotating around the axis, and the satellite translational acceleration measured by an accelerometer when rotating around the axis.

[0047] The center of mass deviation of the satellite rotating around the axis is calibrated according to the on-orbit calibration parameters of the center of mass deviation of the satellite rotating around the axis.

[0048] In practical applications, before performing least squares estimation to obtain the on-orbit calibration parameters of the satellite center of mass deviation when rotating around the axis based on the satellite angular velocity when rotating around the axis, the satellite angular acceleration when rotating around the axis, and the satellite translational acceleration measured by the accelerometer when rotating around the axis, the method further includes:

[0049] The satellite translation acceleration measured by the accelerometer when rotating around the axis is subjected to de-drift and de-biasing processing in sequence to obtain the processed satellite translation acceleration. The main measurement value of the accelerometer is the acceleration vector of the three translational degrees of freedom. The accelerometer outputs the components of this vector in the three directions of the accelerometer coordinate system, which includes the non-conservative acceleration of the satellite platform. and additional accelerations of platform attitude rotation (tangential acceleration and centripetal acceleration).

[0050] Specifically, the translational output of the accelerometer is

[0051] in, is the centripetal acceleration, is the tangential acceleration, is the non-conservative acceleration, is the deviation between the accelerometer and the spacecraft center of mass, i.e., the on-orbit calibration parameter of the satellite center of mass deviation. r x , r y , r z They are the on-orbit calibration parameters of the satellite center of mass deviation in the x direction, the on-orbit calibration parameters of the satellite center of mass deviation in the y direction, and the on-orbit calibration parameters of the satellite center of mass deviation in the z direction. and are the angular velocity and angular acceleration of the satellite, namely ω x ,ω y ,ω z They represent the angular velocity in the x direction, the angular velocity in the y direction, and the angular velocity in the z direction, respectively. They represent the angular acceleration in the x-direction, the angular acceleration in the y-direction, and the angular acceleration in the z-direction, respectively.

[0052] After completing the de-drift and de-biasing processing, the translational output of the accelerometer can be expressed as

[0053]

[0054] Using the least squares method, the satellite centroid deviation can be obtained On-orbit estimate, where the center of mass deviation is a vector that refers to the three-axis deviation between the satellite center of mass and the accelerometer center.

[0055] In practical applications, the data measured by the star sensor when rotating around the axis are sequentially differentiated and differentially processed to obtain the satellite angular velocity and the satellite angular acceleration when rotating around the axis, specifically including:

[0056] The data measured by the star sensor during the rotation around the axis is subjected to differential processing (jump point elimination) to obtain the satellite angular velocity during the rotation around the axis, thereby ensuring the continuity and smoothness of the angular velocity estimated by the star sensor.

[0057] The angular velocity of the satellite when rotating around the axis is differentially processed to obtain the angular acceleration of the satellite when rotating around the axis.

[0058] In practical applications, the least squares estimation is performed based on the satellite angular velocity when rotating around the axis, the satellite angular acceleration when rotating around the axis, and the satellite translational acceleration measured by the accelerometer when rotating around the axis to obtain the on-orbit calibration parameters of the satellite center of mass deviation when rotating around the axis, specifically including:

[0059] A motion matrix when rotating around the axis is obtained according to the satellite angular velocity when rotating around the axis and the satellite angular acceleration when rotating around the axis.

[0060] The least squares estimation method is used to estimate the formula The on-orbit calibration parameters of the satellite center of mass deviation are obtained by processing, where Denotes the satellite centroid deviation using least squares The estimated value of represents the on-orbit calibration parameter of the satellite center of mass deviation, A represents the motion matrix, and A T represents the transpose of A, P represents the weight matrix, represents the satellite translational acceleration.

[0061] In practical applications, obtaining the motion matrix when rotating around the axis according to the satellite angular velocity and the satellite angular acceleration when rotating around the axis specifically includes:

[0062] When rotating around the x-axis, the motion matrix is in, represents the satellite angular acceleration in the x direction, ω x Indicates the satellite angular velocity in the x direction;

[0063] When rotating around the y-axis, the motion matrix is represents the satellite angular acceleration in the y direction, ω y Indicates the satellite angular velocity in the y direction;

[0064] When rotating around the z-axis, the motion matrix is represents the satellite angular acceleration in the z direction, ω z Indicates the satellite's angular velocity in the z direction.

[0065] The satellite center of mass is calibrated on-orbit by performing a specified attitude rotation maneuver on the satellite platform. When the satellite center of mass does not coincide with the location of the accelerometer, the corresponding center of mass deviation is estimated using the translational acceleration generated by the satellite's attitude motion at the accelerometer location. The satellite's attitude motion can be generated using a corresponding sinusoidal or square wave attitude motion signal using the magnetic torquer carried by the satellite platform. To avoid interference from non-conservative forces and considering the limitations of the accelerometer's measurement frequency band, a 0.1 Hz sinusoidal or square wave signal is generally selected. This embodiment of the present invention provides a more specific method for calibrating the center of mass deviation of a gravity satellite for three-axis independent maneuvers. The specific steps are as follows:

[0066] (1) The satellite performs a single-axis square wave excitation signal maneuver to obtain data measured by the accelerometer and star sensor under the satellite's rotation state.

[0067] a. Design of attitude maneuver frequency f: The frequency band that meets the high sensitivity of the accelerometer is 0.1 Hz, because the accelerometer has the lowest noise level at 0.1 Hz.

[0068] b. Design of attitude maneuver amplitude A: The attitude angular velocity caused by the excitation should be within the range allowed by the star sensor; on this basis, the acceleration caused by the center of mass deviation should be as large as possible, and the angular acceleration caused by the rotation should be within erad / s 2 -5rad / s 2 .

[0069] c. Design of the attitude maneuver time span T: A longer time span T improves identification accuracy. The time span refers to the duration of a maneuver in a single direction; however, it should not be too long, as this makes it difficult to maintain linearity in the non-gravitational acceleration term. Therefore, the maximum maneuver time in each direction is set to 300 seconds, with a minimum of no less than 100 seconds. When the selected signal is 0.1Hz, the corresponding maximum number of cycles is 30, and the minimum number of cycles is 10.

[0070] In this embodiment, the magnetorectron excitation signal is designed to use a 0.1Hz square wave. The magnetorectrons MTQ-X and MTQ-Y independently apply saturation magnetic torques to achieve satellite rotation in the X, Y, and Z directions, respectively. The duration is set to 180 seconds, and accelerometer and star sensor data are acquired during this maneuver. To avoid jumps caused by solar pressure, the calibration maneuvering period should be selected when no satellite enters or exits the shadow zone.

[0071] In different regions, the magnetic torque output by the magnetic torquer is cross-multiplied with the geomagnetic field to obtain the generated torque. In high-latitude and low-latitude regions, rotational torques in the XYZ directions around the accelerometer are generated, realizing the center of mass deviation calibration maneuver of three-axis independent maneuvering.

[0072] (2) De-drift and de-bias the data measured by the accelerometer, and perform differential processing on the data measured by the star sensor to obtain the angular velocity, such as Figure 3 shown.

[0073] Since the frequency band of non-conservative force is less than 40mHz, it can be regarded as linear acceleration within 300s, such as Figure 2 As shown in the figure, the attitude modulation introduces a 0.1Hz sinusoidal signal. The influence of non-conservative forces can be removed by using de-drift and debiasing operations. Specifically, an FIR filter can be set to process the data measured by the accelerometer.

[0074] A periodic excitation with a certain frequency f and amplitude A within a certain time span T is designed, so that the acceleration component caused by the center of mass deviation in the accelerometer output changes with this period, while the non-gravity acceleration component still changes linearly.

[0075] (3) Least squares estimation is performed on the star sensor data and accelerometer measurement data under three-axis independent square wave satellite maneuvers to obtain the on-orbit calibration parameters of the satellite center of mass deviation.

[0076] When the accelerometer is not installed at the center of mass of the spacecraft, the translational measurement data of the accelerometer includes not only the effect of non-conservative forces, but also the centripetal acceleration and tangential acceleration introduced by the rotation at the location. For formula (1), and After substituting into formula (2) and expanding it, the basic mathematical model of center of mass calibration can be obtained as follows:

[0077]

[0078] In addition, considering that the accelerometer has different measurement accuracy for translational acceleration in the three directions, assuming that the x-direction is the non-sensitive axis with a measurement accuracy of 1×10-9m / s2 / Hz1 / 2, and the y and z-directions are the sensitive axes with a measurement accuracy of 3×10-10m / s2 / Hz1 / 2. Then, the corresponding weight matrix is ​​defined as

[0079]

[0080] Then the estimated value of the centroid deviation is calculated as follows:

[0081] Here, using formula (5) and combining with the weight matrix P, the satellite center of mass deviation can be estimated by least square fitting according to formula (7), that is,

[0082]

[0083] The estimation accuracy of the centroid deviation in the three directions can be solved. Assuming the unit weight standard deviation is σ = 3×10-10m / s2 / Hz1 / 2, then p1 = 9 / 100, p2 = 1, p3 = 1. At this time, the covariance matrix is The diagonal line is the estimated accuracy of the centroid deviation in three directions.

[0084] The design excites the satellite to rotate once around a specific axis (e.g., the x-axis), and only calibrates the center of mass deviation in two directions (y and z). Separately, square-wave maneuvering of the center of mass deviation in the other two directions is performed independently, allowing all centers of mass to be calibrated (e.g., if rotating around the y-axis, the x and z centers of mass can be calibrated; if rotating around the z-axis, the x and y centers of mass can be calibrated).

[0085] When the satellite is excited to rotate around the x-axis and only the center of mass deviation in the y and z directions is marked, the angular acceleration Angular velocity Matrix A is transformed into

[0086]

[0087]

[0088] According to formula (5) and formula (8), substitute the typical parameters ω x =10-4rad / s2, then the center of mass estimation accuracy in the y and z directions is σ y =3.0×10 -6 m and σ z =3.0×10 -6 m.

[0089] When the satellite is excited to rotate around the y-axis and only the center of mass deviation in the x and z directions is marked, the angular acceleration Angular velocity Matrix A is transformed into

[0090]

[0091]

[0092] According to formula (6), substitute the typical parameters ω y =10-4rad / s2, then the center of mass estimation accuracy in the x and z directions are σ x =3.0×10 -6 m and σ z =1.0×10 -5 m.

[0093] When the satellite is stimulated to rotate around the z-axis and only the center of mass deviation in the x and y directions is marked, the angular acceleration Angular velocity Matrix A is transformed into

[0094]

[0095]

[0096] According to formula (6), substitute the typical parameters ω z =10-4rad / s2, then the center of mass estimation accuracy in the x and y directions is σ x =3.0×10 -6 m and σ y =1.0×10 -5 m.

[0097] It's important to note that in the three-axis independent calibration method, the initial velocity setting does not affect the accuracy of the center of mass estimation. When calibration is performed independently in each of the three directions, the deviation in each direction can be repeated twice. Using GRACEFollow On satellite data and the simulated maneuvering conditions of the proposed method, calibration simulation results were completed with a center of mass deviation of 100 μm.

[0098] Assume that the centroid deviation is To be closer to the actual situation, the x and z directions are deviations along the positive direction of the axis, and the y direction is the deviation along the negative direction of the axis.

[0099] The satellite rotates around the x-axis to calibrate the center of mass deviation in the y and z directions. The satellite rotates around the y-axis to calibrate the center of mass deviation in the x and z directions. The satellite rotates around the z-axis to calibrate the center of mass deviation in the x and y directions. The three calibration results are shown in Table 1:

[0100] Table 1 Summary of calibration results of center of mass deviation

[0101] x direction (μm) y direction (μm) z direction (μm) Rotation around the x-axis — -99.6 98.1 Rotation around the y-axis 99.4 — 114.8 Rotation around the z axis 100.7 -111.8 —

[0102] When the input is When using data from the high-sensitivity axes of the accelerometer and star sensor, when rotating about the x-axis, it is the high-sensitivity axis of the accelerometer that participates in the calculation of the center of mass deviation in the y and z directions; when rotating about the y-axis, it is the high-sensitivity axis of the accelerometer that participates in the calculation of the center of mass deviation in the x direction, and it is the low-sensitivity axis of the accelerometer that participates in the calculation of the center of mass deviation in the z direction; when rotating about the z-axis, it is the low-sensitivity axis of the accelerometer that participates in the calculation. The final estimated values ​​of x, y, and z are 99.4, -99.6, and 98.1 μm, respectively.

[0103] In accordance with the above method, an embodiment of the present invention further provides a center of mass deviation calibration system for three-axis independent maneuvering of a gravity satellite, comprising:

[0104] The acquisition module is used to obtain the satellite translation acceleration measured by the accelerometer and the star sensor data when the satellite rotates around each axis in a three-axis independent rotation maneuver state when the satellite performs the saturation magnetic torque of the magnetic torquer.

[0105] The differential processing module is used to perform differential and difference processing on the data measured by the star sensor when rotating around any one of the three axes to obtain the satellite angular velocity and the satellite angular acceleration when rotating around the axis.

[0106] The parameter determination module is used to perform least square estimation based on the satellite angular velocity when rotating around the axis, the satellite angular acceleration when rotating around the axis, and the satellite translational acceleration measured by the accelerometer when rotating around the axis to obtain the on-orbit calibration parameters of the satellite center of mass deviation when rotating around the axis.

[0107] The calibration module is used to calibrate the center of mass deviation of the satellite when it rotates around the axis according to the on-orbit calibration parameters of the satellite center of mass deviation when it rotates around the axis.

[0108] In practical applications, the parameter determination module specifically includes:

[0109] The motion matrix calculation unit is used to obtain the motion matrix when rotating around the axis according to the satellite angular velocity when rotating around the axis and the satellite angular acceleration when rotating around the axis.

[0110] Parameter determination unit, used to use the least squares estimation method to estimate the formula The on-orbit calibration parameters of the satellite center of mass deviation are obtained by processing, where Denotes the satellite centroid deviation using least squares The estimated value of represents the on-orbit calibration parameter of the satellite center of mass deviation, A represents the motion matrix, and AT represents the transpose of A, P represents the weight matrix, represents the satellite translational acceleration.

[0111] In practical applications, the gravity satellite's three-axis independent maneuvering center of mass deviation calibration system also includes:

[0112] The satellite translation acceleration measured by the accelerometer when the satellite rotates around the axis is sequentially subjected to de-drift and de-biasing processing to obtain the processed satellite translation acceleration.

[0113] In practical applications, the motion matrix calculation unit specifically includes:

[0114] The x motion matrix calculation subunit is used for rotating around the x-axis. The motion matrix is in, represents the satellite angular acceleration in the x direction, ω x Indicates the satellite angular velocity in the x direction.

[0115] The y motion matrix calculation subunit is used for rotating around the y axis. The motion matrix is represents the satellite angular acceleration in the y direction, ω y Indicates the satellite angular velocity in the y direction.

[0116] The z motion matrix calculation subunit is used for rotating around the z axis. The motion matrix is represents the satellite angular acceleration in the z direction, ω z Indicates the satellite's angular velocity in the z direction.

[0117] The present invention has the following technical effects:

[0118] 1. By independently performing three-axis rotation maneuvers on the satellite accelerometer and independently calculating the calibration data of the single-axis independent maneuver, the crosstalk and coupling effects of the three axes of the accelerometer during the satellite's multi-axis rotation maneuver can be significantly reduced, effectively improving the accuracy and confidence of the gravity satellite's center of mass deviation. The obtained satellite center of mass deviation parameters are more accurate, which can effectively guarantee the accuracy of the gravity satellite's gravity field model products.

[0119] 2. By increasing the satellite center of mass deviation maneuvering time to 300 seconds, the signal-to-noise ratio of the maneuvering signal during the center of mass deviation calibration process can be effectively improved, and the accuracy of the center of mass deviation calibration results can be increased.

[0120] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0121] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A method for calibrating the center of mass deviation of a gravity satellite for three-axis independent maneuvers, characterized in that: include: When the satellite is performing the saturation magnetic torque operation of the magnetorectron, the satellite translation acceleration measured by the accelerometer and the star sensor are respectively obtained when the satellite rotates around each axis in the three-axis independent rotation maneuver state; For any one of the three axes, performing differentiation and difference processing on the data measured by the star sensor when rotating around the axis to obtain the satellite angular velocity and the satellite angular acceleration when rotating around the axis; The on-orbit calibration parameters of the satellite center of mass deviation when rotating around the axis are obtained by performing least square estimation based on the satellite angular velocity when rotating around the axis, the satellite angular acceleration when rotating around the axis, and the satellite translation acceleration measured by the accelerometer when rotating around the axis; specifically, the least square estimation method is used to estimate the formula The on-orbit calibration parameters of the satellite center of mass deviation are obtained by processing, where Denotes the satellite centroid deviation using least squares The estimated value of represents the motion matrix, express The transpose of represents the weight matrix, represents the satellite translational acceleration; When rotating around the x-axis, the motion matrix is ,in, represents the satellite angular acceleration in the x direction, Indicates the satellite angular velocity in the x direction; When rotating around the y-axis, the motion matrix is , represents the satellite angular acceleration in the y direction, Indicates the satellite angular velocity in the y direction; When rotating around the z-axis, the motion matrix is , represents the satellite angular acceleration in the z direction, Indicates the satellite angular velocity in the z direction; The center of mass deviation of the satellite rotating around the axis is calibrated according to the on-orbit calibration parameters of the center of mass deviation of the satellite rotating around the axis.

2. The method for calibrating the center of mass deviation of a gravity satellite for three-axis independent maneuvering according to claim 1 is characterized in that: Before performing least squares estimation to obtain the on-orbit calibration parameters of the satellite center of mass deviation when rotating around the axis according to the satellite angular velocity when rotating around the axis, the satellite angular acceleration when rotating around the axis, and the satellite translational acceleration measured by the accelerometer when rotating around the axis, the method further includes: The satellite translation acceleration measured by the accelerometer when the satellite rotates around the axis is sequentially subjected to de-drift and de-biasing processing to obtain the processed satellite translation acceleration.

3. A gravity satellite three-axis independent maneuvering center of mass deviation calibration system, characterized by: include: An acquisition module is used to obtain the satellite translation acceleration measured by the accelerometer and the star sensor when the satellite rotates around each axis in a three-axis independent rotation maneuver state when the satellite performs the saturation magnetic torque operation of the magnetic torquer; A differential processing module is used to sequentially perform differential and difference processing on the data measured by the star sensor when rotating around any one of the three axes to obtain the satellite angular velocity and the satellite angular acceleration when rotating around the axis; The parameter determination module is used to obtain the on-orbit calibration parameters of the satellite center of mass deviation when rotating around the axis by performing least square estimation based on the satellite angular velocity when rotating around the axis, the satellite angular acceleration when rotating around the axis, and the satellite translation acceleration measured by the accelerometer when rotating around the axis; specifically, it includes: a parameter determination unit for using the least square estimation method to estimate the formula The on-orbit calibration parameters of the satellite center of mass deviation are obtained by processing, where Denotes the satellite centroid deviation using least squares The estimated value of represents the motion matrix, express The transpose of represents the weight matrix, represents the satellite translational acceleration; When rotating around the x-axis, the motion matrix is ,in, represents the satellite angular acceleration in the x direction, Indicates the satellite angular velocity in the x direction; When rotating around the y-axis, the motion matrix is , represents the satellite angular acceleration in the y direction, Indicates the satellite angular velocity in the y direction; When rotating around the z-axis, the motion matrix is , represents the satellite angular acceleration in the z direction, Indicates the satellite angular velocity in the z direction; The calibration module is used to calibrate the center of mass deviation of the satellite when it rotates around the axis according to the on-orbit calibration parameters of the satellite center of mass deviation when it rotates around the axis.

4. A gravity satellite three-axis independent maneuvering center of mass deviation calibration system according to claim 3, characterized in that: Also includes: The satellite translation acceleration measured by the accelerometer when the satellite rotates around the axis is sequentially subjected to de-drift and de-biasing processing to obtain the processed satellite translation acceleration.

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