Satellite-borne magnetometer high-precision measurement and correction method

Abstract

A kind of on-board magnetometer high-precision measurement and correction method, comprising: S1, magnetometer signal processing and validity judgment, output magnetic field data;S2, magnetometer is carried out ground comprehensive calibration;S3, based on ground comprehensive calibration result, on-orbit real-time correction compensation.This method has strong universality, can aim at a kind of configuration with magnetometer control system the technical problem of improving on-board magnetometer measurement precision, makes full use of existing resources on satellite and ground calibration means, realizes on-board magnetometer on-orbit high-precision measurement and correction, provides a kind of method for improving magnetometer measurement precision for low-cost small satellite and high-precision magnetic control satellite.

Description

Technical Field

[0001] This invention relates to a high-precision measurement and correction method for a spaceborne magnetometer, belonging to the field of spacecraft attitude measurement and control technology. Background Technology

[0002] Currently, low-Earth orbit spacecraft typically utilize magnetic torquers for attitude control or angular momentum unloading. The geomagnetic field data of the satellite's orbital position used to calculate the magnetic moment of the magnetic torquer is obtained through theoretical calculations using a geomagnetic field model. However, for magnetically controlled spacecraft with high attitude control requirements, the accuracy of the theoretical geomagnetic field data calculated by the geomagnetic field model cannot meet the requirements of high-precision magnetic control, especially in geomagnetic anomaly regions and areas such as the Earth's North and South Poles, where the model's theoretical calculation data has even greater errors. Therefore, it is necessary to propose a high-precision measurement and correction method for spaceborne magnetometers to achieve high-precision magnetic measurement and control of satellites. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and solve the problem that the accuracy of theoretical geomagnetic field data is insufficient to meet the requirements of high-precision magnetic control.

[0004] The objective of this invention is achieved through the following technical solutions:

[0005] A high-precision measurement and correction method for a spaceborne magnetometer includes:

[0006] S1. Magnetometer signal processing and validity assessment, outputting magnetic field data;

[0007] S2. Perform ground-based comprehensive calibration of the magnetometer;

[0008] S3. Based on the ground-based integrated calibration results, real-time on-orbit correction and compensation are performed.

[0009] A computer program product stored on a non-transitory computer-readable medium, the computer program product including program code for implementing the above-described high-precision measurement and correction method for a spaceborne magnetometer.

[0010] An electronic device, comprising:

[0011] Processor; and

[0012] Memory is used to store computer program instructions;

[0013] When the computer program instructions are loaded and run by the processor, the processor executes the above-described high-precision measurement and correction method for the spaceborne magnetometer.

[0014] In one embodiment of the present invention, the magnetometer signal processing and validity judgment include: establishing the relationship between the magnetometer output voltage value and the magnetic field, acquiring the magnetometer head temperature, judging the validity of the magnetometer head temperature, acquiring the magnetometer output voltage with high precision, calculating and compensating for the magnetic field measured by the magnetometer, and judging the validity of the calculated magnetic field data measured by the magnetometer.

[0015] In one embodiment of the present invention, the relationship between the output voltage value of the magnetometer and the magnetic field is obtained by fitting the curve B = K(T)x + b, where B is the magnetic field strength; x is the voltage output value; K(T) is a variable related to the magnetometer head temperature; and T is the magnetometer head temperature.

[0016] In one embodiment of the present invention, the determination of the validity of the magnetometer head temperature includes:

[0017] If the received temperature exceeds the reasonable range, the data is invalid, and a temperature correction of T=23° is performed.

[0018] If the received temperature changes more than the predetermined range twice, the data is invalid, and temperature correction is performed using T=23°.

[0019] In one embodiment of the present invention, the validity determination of the calculated magnetometer measurement magnetic field data includes:

[0020] The three-axis magnetic field measurement values ​​of the magnetometer are Bmm[i] = {Bmm[x], Bmm[y], Bmm[z]}; where i = x, y, z, x represents the X-axis magnetometer, y represents the Y-axis magnetometer, and z represents the Z-axis magnetometer;

[0021] If Bmm[i] > 65000, then set the magnetometer validity flag F_MMValid[i] = 0, that is, the magnetometer validity flag is invalid;

[0022] If the absolute value of the change between the two data collections is greater than 10000, then set F_MMValid[i] = 0, that is, the magnetometer validity flag is invalid;

[0023] If the absolute values ​​of the measured values ​​of Bmm[x], Bmm[y], and Bmm[z] are all less than 100, then

[0024] F_MMValid[x]=0, F_MMValid[y]=0, F_MMValid[z]=0.

[0025] In one embodiment of the present invention, a magnetometer measurement model is established, and the relationship between the magnetometer measurement and the geomagnetic field at the satellite's location is as follows:

[0026] B 卫星 Indicates the magnetic field of satellite equipment. C represents the noise level of the magnetometer measurement. Sc C represents the magnetometer installation error matrix. cb C is the transformation matrix between the nominal magnetometer coordinate system and the celestial coordinate system. bb0 C represents the error matrix between the celestial coordinate system and the actual magnetic field coordinate system. NS B represents the three-axis nonorthogonality matrix of the magnetometer. M0 and K MN These represent the constant and proportional terms of the magnetometer's magnetic flux density, respectively, in a diagonal matrix.

[0027] In one embodiment of the present invention, the magnetic field calibration formula is as follows:

[0028]

[0029] [Bmm[x]Bmm[y]Bmm[z]] T It is the component representation of Bmm[i]. yes The component expression, [X 标称 Y 标称 Z 标称 ] T It is C bb0 B 地磁 The component expression, where C bb0 The data was obtained through precise laboratory measurements, B 地磁 It is a known standard magnetic field; It is the parameter matrix to be calibrated.

[0030] In one embodiment of the present invention, the magnetic field data output by the magnetometer is corrected and compensated in real time on orbit. The correction algorithm is as follows:

[0031]

[0032] Where B = {Bx, By, Bz} is the magnetic field data output in step S1; B_new = {Bx_new, By_new, Bz_new} is the corrected magnetometer data.

[0033] Compared with the prior art, the present invention has the following advantages:

[0034] This method is highly versatile and addresses the technical challenge of improving the measurement accuracy of spaceborne magnetometers in satellites equipped with magnetometer control systems. It fully utilizes existing onboard resources and ground calibration methods to achieve high-precision on-orbit measurement and correction of spaceborne magnetometers. This provides a method for improving the measurement accuracy of magnetometers in low-cost small satellites and high-precision magnetically controlled satellites. This method relies on mature components of the satellite control system, requiring no new measurement or execution components; the algorithm requires relatively little computation, eliminating the need for additional computing resources, thus demonstrating promising market prospects.

[0035] In this method, the coefficients of the first term and the constant term are uniformly used as the parameters to be estimated during ground-based integrated calibration. This can improve the estimation accuracy of the parameters to be estimated, thereby effectively improving the accuracy of the real-time on-orbit measurement data of the magnetometer. It also has good market promotion prospects. Attached Figure Description

[0036] Figure 1 This is a flowchart of a high-precision measurement and correction method for a spaceborne magnetometer according to the present invention. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0038] A high-precision measurement and correction method for a spaceborne magnetometer, such as Figure 1 As shown, it includes:

[0039] S1. Magnetometer signal processing and validity assessment, including: establishing the relationship between the magnetometer output voltage and the magnetic field; magnetometer head temperature acquisition; magnetometer head temperature validity assessment; high-precision acquisition of magnetometer output voltage; calculation and temperature compensation of the magnetometer measured magnetic field based on the validity assessment of the magnetometer data; and validity assessment of the calculated magnetometer measured magnetic field data.

[0040] The specific process is as follows:

[0041] (1) Based on the output characteristics of the magnetometer, the relationship between the output voltage and the magnetic field is established, and the corresponding fitting curve is B=K(T)x+b, where B is the magnetic field strength in nT; x is the voltage output value in V; and K(T) is a variable related to the temperature of the magnetometer head, and the formula is K(T)=(10 9 ×K0) / (10 9 +5×Kt(T-23)×K0), where T is the magnetometer head temperature in °C, and K0 and b are constant coefficients;

[0042] (2) The onboard computer uses the CAN bus to collect the magnetometer head temperature in real time.

[0043] (3) The validity of the calculated magnetometer head temperature is determined by the following steps:

[0044] (3.1) If the received temperature exceeds the reasonable range (-55.2°*Tmmk1~77°*Tmmk2), the data is invalid, and a temperature correction of T=23° is performed. Tmmk1 is the judgment threshold coefficient 1, and Tmmk2 is the judgment threshold coefficient 2.

[0045] (3.2) If the received temperature changes by more than 5°*Tmmk3 between two consecutive readings, the data is invalid, and a temperature correction of T=23° is performed. Tmmk3 is the judgment threshold coefficient of 3. The magnetometer temperature history values ​​are updated unconditionally.

[0046] (4) The onboard computer uses D / A converter to acquire the output voltage of the magnetometer with high precision, acquires it 5 times in a row, and performs smoothing filtering on the acquired data.

[0047] (5) Perform the calculation and temperature compensation of the magnetic field measured by the magnetometer according to the method described in step (1) to obtain the three-axis magnetic field measurement values ​​Bmm[i]={Bmm[x]、Bmm[y]、Bmm[z]}. Where i=x、y、z, x represents the X-axis magnetometer, y represents the Y-axis magnetometer, and z represents the Z-axis magnetometer.

[0048] (6) The validity of the calculated magnetic field data measured by the magnetometer is determined by the following steps:

[0049] (a) If Bmm[i] > 65000, then set the magnetometer validity flag F_MMValid[i] = 0 (invalid);

[0050] (b) If the absolute value of the change between the two data collections is greater than 10000, then set F_MMValid[i] = 0 (invalid);

[0051] (c) If the absolute values ​​of the measured values ​​of Bmm[x], Bmm[y], and Bmm[z] are all less than 100, then

[0052] F_MMValid[x]=0, F_MMValid[y]=0, F_MMValid[z]=0.

[0053] S2. Ground-based integrated calibration. The specific process is as follows:

[0054] A magnetometer measurement model is established, and the relationship between the magnetometer measurement and the geomagnetic field at the satellite's location is shown in the following formula. Here B 卫星 Indicates the magnetic field of satellite equipment. C represents the noise level of the magnetometer measurement. Sc C represents the magnetometer installation error matrix. cb C is the transformation matrix between the nominal magnetometer coordinate system and the celestial coordinate system. bb0 C represents the error matrix between the celestial coordinate system and the actual magnetic field coordinate system. NS B represents the three-axis nonorthogonality matrix of the magnetometer. M0 and K MN Let C represent the constant and proportional terms of the magnetometer's magnetic flux density, respectively, in a diagonal matrix. NS and K MNIt is generally not an orthogonal matrix.

[0055] The magnetic field calibration formula is established as follows:

[0056]

[0057] Here [Bmm[x]Bmm[y]Bmm[z]] T It is the component representation of Bmm[i]. yes The component expression, [X 标称 Y 标称 Z 标称 ] T It is C bb0 B 地磁 The component expression, where C bb0 The data was obtained through precise laboratory measurements, B 地磁 It is a known standard magnetic field. It is the parameter matrix to be calibrated.

[0058] The comprehensive coefficient calibration takes into account the influence of factors such as the magnetic flux density of the onboard magnetometer, installation error, and the non-orthogonality of the magnetometer's three axes. Under a zero-magnetic test environment, more than four sets of calibration condition tests are conducted to obtain the standard magnetic field input and measurement output combination. Using least squares or other estimation methods, 12 parameters to be determined can be estimated.

[0059] S3. Real-time on-orbit correction and compensation. The specific process is as follows:

[0060] The ground-based integrated calibration parameters are loaded into the onboard computer application software. During application software initialization, the ground-based integrated calibration parameters are read, and the magnetic field data output by the magnetometer is corrected and compensated in real time on orbit. The correction algorithm is as follows:

[0061]

[0062] Where B = {Bx, By, Bz} is the output magnetic field data of S1; B0 = {Bx0, By0, Bz0} and the K coefficient matrix are determined according to the parameter matrix to be calibrated in S2; B_new = {Bx_new, By_new, Bz_new} is the corrected magnetometer data.

[0063] When F_MMValid[i] is invalid, the corresponding axis parameters in B = {Bx, By, Bz} and B0 = {Bx0, By0, Bz0} in the above compensation algorithm are set to zero, and the above compensation calculation is performed again.

[0064] The contents not described in detail in this specification are common knowledge to those skilled in the art.

[0065] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A high-precision measurement and correction method for a spaceborne magnetometer, characterized in that, include: S1. Magnetometer signal processing and validity assessment, outputting magnetic field data; The magnetometer signal processing and validity assessment includes: establishing the relationship between the magnetometer output voltage and the magnetic field; acquiring the magnetometer head temperature; assessing the validity of the magnetometer head temperature; acquiring the magnetometer output voltage with high precision; calculating and compensating for the magnetic field measured by the magnetometer; and assessing the validity of the calculated magnetic field data. The relationship between the output voltage of the magnetometer and the magnetic field is fitted using the curve B = K(T)x + b, where B is the magnetic field strength; x is the voltage output value; K(T) is a variable related to the magnetometer head temperature; and T is the magnetometer head temperature. If the received temperature exceeds the reasonable range, the data is invalid, and temperature correction is performed using T=23°; if the received temperature changes more than the predetermined range twice, the data is invalid, and temperature correction is performed using T=23°. The validity assessment of the calculated magnetometer measurement magnetic field data includes: The three-axis magnetic field measurement values ​​of the magnetometer are Bmm[i] = {Bmm[x], Bmm[y], Bmm[z]}; where i = x, y, z, x represents the X-axis magnetometer, y represents the Y-axis magnetometer, and z represents the Z-axis magnetometer; If Bmm[i] > 65000, then set the magnetometer validity flag F_MMValid[i] = 0, that is, the magnetometer validity flag is invalid; If the absolute value of the change between the two data collections is greater than 10000, then set F_MMValid[i] = 0, that is, the magnetometer validity flag is invalid; If the absolute values ​​of the measured values ​​of Bmm[x], Bmm[y], and Bmm[z] are all less than 100, then F_MMValid[x]=0, F_MMValid[y]=0, F_MMValid[z]=0; S2. Perform ground-based comprehensive calibration of the magnetometer; establish a magnetometer measurement model, and the relationship between the magnetometer measurement and the geomagnetic field at the satellite's location is as follows: B 卫星 Indicates the magnetic field of satellite equipment. C represents the noise level of the magnetometer measurement. Sc C represents the magnetometer installation error matrix. cb C is the transformation matrix between the nominal magnetometer coordinate system and the celestial coordinate system. bb0 C represents the error matrix between the celestial coordinate system and the actual magnetic field coordinate system. NS B represents the three-axis nonorthogonality matrix of the magnetometer. M0 and K MN These represent the constant and proportional terms of the magnetometer's magnetic flux density, respectively, in a diagonal matrix. The magnetic field calibration formula is as follows: [Bmm[x]Bmm[y]Bmm[z]] T It is the component representation of Bmm[i]. yes The component expression, [X 标称 Y 标称 Z 标称 ] T It is C bb0 B 地磁 The component expression, where C bb0 The data was obtained through precise laboratory measurements, B 地磁 It is a known standard magnetic field; It is the parameter matrix to be calibrated; The magnetic field data output by the magnetometer is corrected and compensated in real time on orbit. The correction algorithm is as follows: Where B = {Bx, By, Bz} is the magnetic field data output in step S1; B_new = {Bx_new, By_new, Bz_new} is the corrected magnetometer data; S3. Based on the ground-based integrated calibration results, real-time on-orbit correction and compensation are performed.

2. A computer program product stored on a non-transitory computer-readable medium, the computer program product comprising program code for performing the method as claimed in claim 1.

3. An electronic device, comprising: processor; as well as Memory is used to store computer program instructions; When the computer program instructions are loaded and run by the processor, the processor performs the method as described in claim 1.

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