A method for calibrating the onboard magnetometer of mass-produced satellites under interference.

Abstract

This invention proposes a calibration method for satellite-borne magnetometers on mass-produced satellites to address satellite interference. This method involves measuring the ambient magnetic field strength at a fixed location, placing the satellite-borne magnetometer on the mass-produced satellite at the same location, and subtracting the ambient magnetic field strength from the measured value of the satellite-borne magnetometer to obtain the interference data of the satellite-borne magnetometer. The advantages of this method are that the calibration is fast, it does not require specialized ground magnetic environment simulation equipment, and the calibration accuracy is not sensitive to changes in the on-board magnetic field gradient.

Description

Technical Field

[0001] This invention relates to the field of spacecraft technology, and in particular to a method for calibrating the interference-induced magnetometer of a mass-produced satellite. Background Technology

[0002] As a sensor for the magnetic field strength of the sensitive space environment on a satellite, the magnetometer is subject to interference from the remanent moment of the entire satellite, which can cause measurement errors. In order to ensure the measurement accuracy of the onboard magnetometer, after implementing remanent magnetization control on the satellite, it is necessary to calibrate the interference value of the entire satellite on the magnetic field strength measured by the onboard magnetometer in order to compensate for it.

[0003] Currently, common methods for calibrating the magnitude of interference from the entire satellite to a spaceborne magnetometer include the zero-magnetic-space calibration method and the ground-based standard magnetometer proximity method.

[0004] The zero-magnetic space calibration method uses a large-scale ground-based magnetic environment simulation device to establish a uniform zero-magnetic field environment at the center of the device, so that the satellite can be placed in a zero-magnetic field environment to measure the magnetic interference to the onboard magnetometer.

[0005] The ground-based standard magnetometer proximity method involves placing a ground-based standard magnetometer close to the satellite-borne magnetometer, keeping the ground-based standard magnetometer stationary, and then moving the satellite to measure the changes in the ground-based standard magnetometer's readings with and without the satellite present. This method is used to approximate the interference of the satellite on the satellite-borne magnetometer.

[0006] The drawbacks of these two methods are that the former requires specialized environmental simulation equipment and the uniform magnetic field region of the zero magnetic field environment must be larger than the satellite's outer envelope; the latter has poor accuracy of interference calibration results when the satellite envelope is limited and the on-board magnetic field gradient is large, making it difficult to meet the calibration requirements of the on-board magnetometer. Summary of the Invention

[0007] With the launch and deployment of low-Earth orbit satellite constellations, satellites are being mass-produced and their envelopes are limited, thus the aforementioned calibration methods for spaceborne magnetometers subject to satellite interference have certain limitations. To address these issues, this invention provides a method for calibrating spaceborne magnetometers on mass-produced satellites to withstand interference, characterized by comprising:

[0008] Provide non-magnetic fixtures for parking satellites to be calibrated;

[0009] Provides structural simulation of stars;

[0010] Measure the ambient magnetic field strength. If the ambient magnetic field strength changes below the preset threshold of the first test within a certain period of time, continue the subsequent operations.

[0011] Record the ambient magnetic field strength B after the structure is powered on the simulated satellite. 基准0 And the environmental magnetic field strength B after the simulated star is moved away. 标磁0 ;

[0012] The first batch of satellites was placed on the non-magnetic fixture, putting the satellites into operation, and the ambient magnetic field strength B measured by the onboard magnetometer of the first batch of satellites was recorded. 批产星1 And record the environmental magnetic field strength B after the first batch of satellites was removed. 标磁1 ;

[0013] Repeat the previous step to record the ambient magnetic field strength B measured by the onboard magnetometer of the i-th batch of satellites. 批产星i The i-th batch of satellites is removed from the non-magnetic fixture, and the ambient magnetic field strength is recorded again, denoted as B. 标磁i , where i is a positive integer; and

[0014] When the ambient magnetic field strength B 标磁i With the strength of the ambient magnetic field B 标磁0 When the difference is less than the preset threshold of the second test, the calibration value ΔB of the onboard magnetometer of the i-th batch satellite affected by satellite interference is determined. i =B 批产星i -B 基准0 .

[0015] In one embodiment of the present invention, the non-magnetic fixture has a height of not less than 2 meters and is equipped with a fixed interface for mechanical connection with the satellite to be calibrated, so that the satellite will not move after being placed in the non-magnetic fixture.

[0016] In another embodiment of the present invention, the structural simulation star is made of non-magnetic materials and processed according to the mass production satellite state.

[0017] In another embodiment of the present invention, the characteristic is that when the structural simulation star is placed on the non-magnetic fixture, the spatial position of the onboard magnetometer installed on the structural model star relative to the non-magnetic fixture is the same as the spatial position of the onboard magnetometer on the batch production satellite relative to the non-magnetic fixture when the batch production satellite is placed on the non-magnetic fixture.

[0018] In another embodiment of the present invention, measuring the ambient magnetic field strength further includes:

[0019] Place the simulated star structure onto the non-magnetic fixture;

[0020] The area around the simulated satellite should be kept empty, free of electrical equipment and strong magnetic materials, within a radius of 3 to 5 times the satellite envelope size; and

[0021] A ground-based standard magnetometer is placed near the onboard magnetometer of the simulated star to monitor changes in the ambient magnetic field strength.

[0022] In another embodiment of the present invention, the ground standard magnetometer remains in a fixed position throughout the test.

[0023] In another embodiment of the present invention, placing the first batch of satellites on the non-magnetic fixture to put the batch of satellites into a working state further includes:

[0024] The first batch-produced satellite requiring magnetometer interference calibration is placed on the non-magnetic fixture to ensure that the space environment location of the onboard magnetometer of the first batch-produced satellite is the same as that of the onboard magnetometer of the structural simulation satellite; and

[0025] Establish and maintain the operational status of the first batch of satellites based on their on-orbit operating conditions.

[0026] In another embodiment of the present invention, the preset threshold for the first test is 10nT / 5min.

[0027] In another embodiment of the present invention, the preset threshold for the second test is 30nT.

[0028] This invention proposes a calibration method for satellite-borne magnetometers on mass-produced satellites to address satellite interference. This method involves measuring the ambient magnetic field strength at a fixed location, placing the satellite-borne magnetometer on the mass-produced satellite at the same location, and subtracting the ambient magnetic field strength from the measured value of the satellite-borne magnetometer to obtain the interference data of the satellite-borne magnetometer. The advantages of this method are that the calibration is fast, it does not require specialized ground magnetic environment simulation equipment, and the calibration accuracy is not sensitive to changes in the on-board magnetic field gradient. Attached Figure Description

[0029] Figure 1 A flowchart of a calibration method according to an embodiment of the present invention is shown. Detailed Implementation

[0030] In the following description, the invention is described with reference to various embodiments. However, those skilled in the art will recognize that the embodiments may be practiced without one or more specific details or with other alternatives and / or additional methods, materials, or components. In other instances, well-known structures, materials, or operations are not shown or described in detail so as not to obscure the inventive points of the invention. Similarly, for illustrative purposes, specific quantities, materials, and configurations are set forth to provide a comprehensive understanding of embodiments of the invention. However, the invention is not limited to these specific details.

[0031] Furthermore, it should be understood that the embodiments shown in the accompanying drawings are illustrative and not necessarily drawn to scale. In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not explicitly or implicitly suggest that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention.

[0032] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. In this specification, references to "an embodiment" or "this embodiment" mean that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment of the invention. The phrase "in one embodiment" appearing throughout this specification does not necessarily refer to the same embodiment in all instances.

[0033] With the launch and deployment of low-Earth orbit satellite constellations, satellites are being mass-produced and their envelopes are limited, rendering the aforementioned calibration methods for spaceborne magnetometers susceptible to satellite interference somewhat restrictive. This invention proposes a calibration method for spaceborne magnetometers on mass-produced satellites that addresses satellite interference.

[0034] The following is combined with Figure 1 The flowchart illustrates the calibration method of the onboard magnetometer of mass-produced satellites according to the present invention, which is subject to satellite interference.

[0035] like Figure 1 As shown, this method is suitable for step 1, in which a non-magnetic fixture is designed and fabricated to hold the satellite to be calibrated. In one embodiment of the invention, the non-magnetic fixture designed and fabricated in step 1 for holding the satellite to be calibrated requires that the height of the non-magnetic fixture be no less than 2 meters, and that it have a fixed interface for mechanical connection with the satellite to be calibrated, so that the satellite will not move after being placed in the non-magnetic fixture. It should be noted that the value of the height of the non-magnetic fixture is merely exemplary, and other values, such as 1 meter, 3 meters, etc., can also be used in other embodiments. The mechanical connection can be welding, bolting, etc., and is not limited in detail here.

[0036] In step 2, a structural simulation satellite is fabricated using non-magnetic materials, and the fabrication process is based on the mass-produced satellite specifications. In one embodiment of the invention, step 2 involves fabricating the structural simulation satellite using non-magnetic materials according to the mass-produced satellite specifications. The fabrication requirement is simply to ensure that when the structural simulation satellite is placed on the non-magnetic fixture, the spatial position of the onboard magnetometer mounted on the structural simulation satellite relative to the non-magnetic fixture is consistent with the spatial position of the onboard magnetometer on the mass-produced satellite relative to the non-magnetic fixture when the mass-produced satellite is placed on the non-magnetic fixture. This eliminates the influence of spatial position on the measurement of the environmental magnetic field.

[0037] In step 3, the ambient magnetic field strength is measured. If the ambient magnetic field strength remains below a first preset threshold for a given period of time, subsequent operations continue. In one embodiment of this invention, the first preset threshold is 10 nT / 5 min. That is, if the ambient magnetic field strength remains below 10 nT / 5 min for a given period of time, subsequent operations can proceed; otherwise, the measurement is repeated until it falls below the preset value. It should be noted that the value of the first preset threshold is merely exemplary. In other embodiments, other values ​​for the first preset threshold can be used, such as 5 nT / 5 min, 15 nT / 5 min, 20 nT / 5 min, etc.

[0038] Furthermore, in one embodiment of the present invention, step 3 may further include:

[0039] Place the simulated star structure onto the non-magnetic fixture;

[0040] The area around the simulated star should be kept empty within 3 to 5 times the size of the satellite envelope, i.e., free of electrical equipment and strong magnetic materials. Here, strong magnetic materials refer to materials with a remanence of 1.0-1.4 Tesla (T) or higher.

[0041] A ground-based standard magnetometer is placed near the onboard magnetometer of the simulated star to monitor changes in the ambient magnetic field strength.

[0042] The ground standard magnetometer was kept in the same position during subsequent operations to eliminate the influence of positional factors.

[0043] In step 4, the ambient magnetic field strength B after the structure simulates the satellite's onboard power is recorded. 基准0 And the environmental magnetic field strength B after the simulated star is moved away. 标磁0 ;

[0044] In step 5, the first batch-produced satellite is placed on the non-magnetic fixture, putting it into operational status. The ambient magnetic field strength B measured by the onboard magnetometer of the first batch-produced satellite is recorded at this time. 批产星1 And record the environmental magnetic field strength B after the first satellite of the batch production was removed.标磁1 .

[0045] In one embodiment of the present invention, step 5 may further include:

[0046] The first batch of satellites that needs to be calibrated for magnetometer interference is placed on the non-magnetic fixture to ensure that the space environment location of the onboard magnetometer of the first batch of satellites is the same as that of the onboard magnetometer of the structural simulation satellite.

[0047] Establish and maintain the operational status of the first batch of satellites based on their on-orbit operating conditions.

[0048] In step 6, repeat step 5 and record the ambient magnetic field strength B measured by the onboard magnetometer of the i-th satellite in the batch production (i is a natural number, for example, i = 1, 2, ..., n). 批产星i Subsequently, the i-th satellite was removed from the non-magnetic fixture, and the ambient magnetic field strength at this time was recorded again, denoted as B. 标磁i ;

[0049] In step 7, when the ambient magnetic field strength B mentioned in step 6... 标磁i The ambient magnetic field strength B in step 4 标磁0 When the difference is less than the preset threshold of the second test, the calibration value ΔB of the onboard magnetometer of the i-th batch satellite is affected by satellite interference. i =B 批产星i -B 基准0 .

[0050] The second test preset threshold can be, for example, 30nT, that is, when B 标磁i -B 标磁0 When the value is less than 30 nT, the calibration data of the onboard magnetometer of the i-th batch-produced satellite under satellite interference can be considered valid, and thus the calibration value ΔB of the onboard magnetometer of the i-th batch-produced satellite under satellite interference can be obtained. i =B 批产星i -B 基准0 It should be noted that the value of the second test preset value is merely exemplary. In other embodiments, other values ​​of the second test preset value may also be used, such as 25nT, 35nT, 40nT, etc.

[0051] In summary, this invention proposes a calibration method for satellite-borne magnetometers on mass-produced satellites to address satellite interference. This method involves measuring the ambient magnetic field strength at a fixed location, placing the satellite-borne magnetometer on the mass-produced satellite at the same location, and subtracting the ambient magnetic field strength from the measured value of the satellite-borne magnetometer to obtain the interference data of the satellite-borne magnetometer. The advantages of this method are fast calibration speed, no need for specialized ground magnetic environment simulation equipment, and insensitivity to changes in the onboard magnetic field gradient in calibration accuracy.

[0052] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for calibrating the interference-induced performance of a spaceborne magnetometer on a mass-produced satellite, characterized in that, include: Provide non-magnetic fixtures for parking satellites to be calibrated; Provides structural simulation of stars; Measure the ambient magnetic field strength. If the ambient magnetic field strength changes below the preset threshold of the first test within a certain period of time, continue the subsequent operations. Record the ambient magnetic field strength B after the structure is powered on the simulated satellite. 基准0 And the environmental magnetic field strength B after the simulated star is moved away. 标磁0 ; The first batch of satellites was placed on the non-magnetic fixture, putting the satellites into operation, and the ambient magnetic field strength B measured by the onboard magnetometer of the first batch of satellites was recorded. 批产星1 And record the environmental magnetic field strength B after the first batch of satellites was removed. 标磁1 ; Repeat the previous step to record the ambient magnetic field strength B measured by the onboard magnetometer of the i-th batch of satellites. 批产星i The i-th batch of satellites is removed from the non-magnetic fixture, and the ambient magnetic field strength is recorded again, denoted as B. 标磁i , where i is a positive integer; as well as When the ambient magnetic field strength B 标磁i With the strength of the ambient magnetic field B 标磁0 When the difference is less than the preset threshold of the second test, the calibration value ΔB of the onboard magnetometer of the i-th batch satellite affected by satellite interference is determined. i =B 批产星i -B 基准0 .

2. The calibration method as described in claim 1, characterized in that, The non-magnetic fixture is at least 2 meters high and is equipped with a fixed interface for mechanical connection with the satellite to be calibrated, so that the satellite will not move after being placed in the non-magnetic fixture.

3. The calibration method as described in claim 1, characterized in that, The simulated satellite structure is made of non-magnetic materials and processed according to the mass production satellite specifications.

4. The calibration method as described in claim 1, characterized in that, When the structural simulation satellite is placed on the non-magnetic fixture, the spatial position of the onboard magnetometer installed on the structural simulation satellite relative to the non-magnetic fixture is the same as the spatial position of the onboard magnetometer on the batch production satellite relative to the non-magnetic fixture when the batch production satellite is placed on the non-magnetic fixture.

5. The calibration method as described in claim 1, characterized in that, Measuring the strength of the ambient magnetic field also includes: Place the simulated star structure onto the non-magnetic fixture; The area around the simulated satellite should be kept empty, free of electrical equipment and strong magnetic materials, within a radius of 3 to 5 times the satellite envelope size; and A ground-based standard magnetometer is placed near the onboard magnetometer of the simulated star to monitor changes in the ambient magnetic field strength.

6. The calibration method as described in claim 5, characterized in that, The ground-based standard magnetometer remained in a fixed position throughout the test.

7. The calibration method as described in claim 1, characterized in that, Placing the first batch of satellites on the non-magnetic fixture and putting the batch of satellites into operational status also includes: The first batch-produced satellite requiring magnetometer interference calibration is placed on the non-magnetic fixture to ensure that the space environment location of the onboard magnetometer of the first batch-produced satellite is the same as that of the onboard magnetometer of the structural simulation satellite; and Establish and maintain the operational status of the first batch of satellites based on their on-orbit operating conditions.

8. The calibration method as described in claim 1, characterized in that, The preset threshold for the first test is 10nT / 5min.

9. The calibration method as described in claim 1, characterized in that, The preset threshold for the second test is 30 nT.

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