Atomic magnetometer external field low-magnetism heading error testing method and atomic magnetometer external field low-magnetism heading error testing system

Abstract

The invention provides an atom magnetometer external field low magnetic course error test method and system, a magnetometer to be tested and a reference magnetometer are installed in a calibration turntable, the two magnetometers are differentiated to eliminate environmental magnetic field fluctuation, a turntable control system controls the three-axis rotation direction of the turntable through a universal transmission rod, and the calibration turntable is used for calibrating the external field low magnetic course error. And the course error test is realized through a fixed process, and the used skyscreen is used for providing necessary rainy day protection capability for the test system, so that the environmental adaptability is improved. According to the method, strict non-magnetic design is carried out on each component, and the residual magnetism of each component needs to be less than 1nT level, so that various environmental interferences in an external field test environment are avoided, and the environmental applicability and robustness are improved. By applying the technical scheme of the invention, the technical problems of variable geomagnetic field directions, large magnetic field environment fluctuation and low manual calibration efficiency in the course error calibration process of the atom magnetometer in the prior art are solved.

Description

Technical Field

[0001] The invention relates to the field of quantum sensing technology, and in particular to a method and system for testing an external field low-magnetic heading error of an atomic magnetometer. Background Art

[0002] At present, the requirements for sensitivity and volume of commercial magnetometers are increasing. Atomic magnetometers, as a new generation of magnetometers, have a sensitivity that exceeds that of traditional magnetometers. The sensitivity level of commercial scalar atomic magnetometers suitable for geomagnetic fields is at the level of 1pT / Hz1 / 2, which provides new possibilities for geomagnetic field measurement, geomagnetic navigation and resource exploration. However, due to the limitations of existing material production and manufacturing processes, atomic magnetometers inevitably have nT-level remanent magnetism, which in turn projects the heading error of atomic magnetometers. Since atomic magnetometers inevitably have attitude changes during actual use, in order to avoid false magnetic fields limiting the magnetic field resolution of atomic magnetometers during magnetic field measurement, how to calibrate the heading error of atomic magnetometers while avoiding limiting the high sensitivity of atomic magnetometers has become a necessary task and challenge. Due to the different application scenarios of atomic magnetometers, atomic magnetometers need to calibrate heading errors in actual use environments. The geomagnetic field inclination angles are different in different use environments. How to build non-magnetic equipment to assist atomic magnetometers in adapting to different magnetic inclination angles is one of the necessary tasks of universal testing equipment. It is worth noting here that, in theory, the heading error can be calibrated by simulating the outdoor environment under laboratory conditions. However, the magnetic field environment in the laboratory is currently affected by the magnetic field gradient, resulting in significant differences between the laboratory test results and the outdoor test results. Therefore, it is directly chosen to conduct the heading error test in the outdoor field with a relatively uniform magnetic field to reduce the error. In addition, due to the difference between the real environment and the shielding environment in the laboratory, there are environmental magnetic field interferences such as cars, power cables, ships, and the test equipment itself. The heading error calibration needs to overcome various environmental interferences to improve accuracy. Also due to the high sensitivity of atomic magnetometers, there is currently a lack of automated testing processes for atomic magnetometers. The traditional laboratory stage atomic magnetometer heading error test method is in the manual testing stage, which limits the mass production and application of atomic magnetometers. Summary of the invention

[0003] The present invention provides an atomic magnetometer external field low magnetic heading error test method and system, which can solve the technical problems of changeable geomagnetic field direction, large magnetic field environment fluctuation and low manual calibration efficiency in the atomic magnetometer heading error calibration process in the prior art.

[0004] According to one aspect of the present invention, a method for testing the low magnetic heading error of an atomic magnetometer in an external field is provided. The method comprises: setting a skylight, a calibration turntable, a universal transmission rod and a turntable control system, wherein the turntable control system comprises a control computer and a three-channel servo motor, and the calibration turntable comprises a reference magnetometer fixture, a magnetometer to be tested fixture, a three-axis turntable, a level and a three-axis magnetic resistance; using the skylight to provide shielding for the heading error test to ensure the test continuity after the test is powered on; using the magnetometer to be tested fixture to fix the magnetometer to be tested on the three-axis turntable, and using the reference magnetometer fixture to fix the reference magnetometer outside the three-axis turntable to provide reference for the magnetometer to be tested during the calibration test. Considering the magnetic field, the magnetic field signals of the magnetometer to be tested and the reference magnetometer are phase-differenced to eliminate the influence of common magnetic field interference sources in the external field on the magnetic field; when installing the calibration turntable, the level installed in the calibration turntable needs to be used to stably install the three-axis turntable on the ground to provide a stable environment for magnetometer debugging; after installing the two magnetometers on the three-axis turntable, the direction of the geomagnetic field is identified with the help of the three-axis magnetic resistance, and the three-axis turntable is rotated to align the sensitive axis of the atomic magnetometer with the direction of the geomagnetic field to avoid the influence of the geomagnetic field inclination on the test results; the three-axis turntable is connected to the three-channel servo motor by a universal transmission rod, and the action of the three-channel servo motor is transmitted to the three-axis turntable; the automatic test of the low magnetic heading error of the atomic magnetometer in the external field is completed by using the automated test process in the control computer.

[0005] Furthermore, the automatic test process in the control computer is used to complete the automatic test of the low magnetic heading error of the atomic magnetometer external field, which specifically includes: defining the sensitivity direction of the atomic magnetometer as the y direction, the direction sensitive to the rolling action as the x direction, and the direction sensitive to the heading action as the z direction; dividing the full range of the magnetic field in the z direction of the atomic magnetometer into 11 positions, and the servo motor uses the universal transmission shaft to rotate the heading action by ±60° at each position, and records the differential magnetic field of the two magnetometers at the same time, taking the position with the minimum bias change of the differential magnetic field data in the 11 positions, taking the two adjacent positions of the minimum position as the upper and lower limits, and evenly taking 21 positions again, and rotating the heading action by ±60° at each position again, synchronously recording the differential magnetic field data, and taking the position with the minimum bias change of the differential magnetic field as the magnetic field compensation value in the z direction; after the heading position of the magnetometer returns to zero, dividing the full range of the magnetic field in the y direction of the atomic magnetometer into 11 positions, and the servo motor uses the universal transmission shaft to rotate the heading action by ±60° at each position, and records the differential magnetic field of the two magnetometers at the same time, and taking the differential magnetic field in the 11 positions. The position with the minimum change of the magnetic field data bias is divided into 11 positions, and the two adjacent positions of the minimum position are used as the upper and lower limits. 21 positions are evenly selected again, and the heading action is rotated ±60° at each position again. The differential magnetic field data is recorded synchronously, and the position with the minimum change of the differential magnetic field bias is taken as the magnetic field compensation value in the y direction; after the heading position of the magnetometer is returned to zero, the full range of the magnetic field in the x direction of the atomic magnetometer is evenly divided into 11 positions. The servo motor uses the universal transmission shaft to perform a rolling action and rotate ±60° at each position. At the same time, the differential magnetic field of the two magnetometers is recorded, and 1 is taken. The position with the minimum bias change of differential magnetic field data in position 1 is taken as the upper and lower limits, and the two adjacent positions of the minimum position are taken evenly again. The rolling action at each position is rotated ±60° again, and the differential magnetic field data is recorded synchronously. The position with the minimum bias change of differential magnetic field is taken as the magnetic field compensation value in the x direction; the rolling direction is set to zero, and the servo motor controls the three-axis turntable to rotate the sensitive axis direction of the atomic magnetometer 180°. Repeat the above steps to test again, output two sets of magnetometer compensation values, and complete the low magnetic heading error test of the atomic magnetometer in the external field.

[0006] Furthermore, the frame of the canopy is made of a wave fiber or carbon fiber frame, the metal fixing structure of the canopy is made of a titanium metal material, and the ground nails of the canopy are made of a plastic material.

[0007] Furthermore, the three-axis turntable is manufactured using polyimide plastic material, and the fixing structure of the calibration turntable is fixed using plastic or nylon screws.

[0008] Furthermore, the universal transmission rod is integrally processed and customized using polytetrafluoroethylene or the like.

[0009] Furthermore, the universal transmission rod increases the distance between the calibration turntable and the three-axis servo motor to more than 2m.

[0010] Furthermore, the distance between the control computer and the calibration turntable is greater than or equal to 5m.

[0011] According to another aspect of the present invention, an atomic magnetometer external field low magnetic heading error test system is provided, and the atomic magnetometer external field low magnetic heading error test system uses the atomic magnetometer external field low magnetic heading error test method described above to perform heading error test.

[0012] Furthermore, the atomic magnetometer external field low magnetic heading error test system includes a skylight, a calibration turntable, a universal transmission rod and a turntable control system, the turntable control system includes a control computer and a three-channel servo motor, the calibration turntable includes a reference magnetometer fixture, a magnetometer to be tested fixture, a three-axis turntable, a level and a three-axis magnetic resistance, the skylight is used to provide shielding for the heading error test to ensure the test continuity after the test is powered on, the magnetometer to be tested fixture is used to fix the magnetometer to be tested on the three-axis turntable, and the reference magnetometer fixture is used to fix the reference magnetometer on the outside of the three-axis turntable to provide a magnetometer to be tested during the calibration test process. The reference magnetic field, the magnetic field signals of the magnetometer to be tested and the reference magnetometer are phase-differenced to eliminate the influence of common magnetic field interference sources in the external field on the magnetic field; the level is used to stably install the three-axis turntable on the ground to provide a stable environment for magnetometer debugging; the three-axis magnetic resistance is used to identify the direction of the geomagnetic field, and the three-axis turntable is rotated to align the sensitive axis of the atomic magnetometer with the direction of the geomagnetic field to avoid the influence of the geomagnetic field inclination on the test results; the universal transmission rod is used to connect the three-axis rotation mechanism of the three-axis turntable with the three-channel servo motor, and transmit the action of the three-channel servo motor to the three-axis turntable, and the control computer is used to complete the automatic test of the low magnetic heading error of the atomic magnetometer in the external field.

[0013] By applying the technical solution of the present invention, a method for testing the low-magnetic heading error of an atomic magnetometer in an outdoor field is provided. The method includes a canopy, a calibration turntable, a universal transmission rod and a turntable control system. The magnetometer to be tested and the reference magnetometer are installed in the calibration turntable. The two magnetometers are differentiated to eliminate environmental magnetic field fluctuations, avoid various environmental interferences in the outdoor test environment, and improve environmental applicability and robustness. The turntable control system controls the three-axis rotation direction of the turntable and the necessary rotation actions required for the heading error test through the universal transmission rod, and realizes the heading error test through a fixed process. The canopy used is used to provide the test system with necessary rain protection capabilities to improve environmental adaptability. Due to the different geomagnetic inclinations in different use environments, the three-axis turntable integrates the three-axis magnetic resistance to effectively solve the specific environment applicability in the heading error calibration process. The servo motor is used to automatically control the three-axis rotation process, realize the automatic calibration process of the heading error of the atomic magnetometer, and improve the test efficiency of the atomic magnetometer in the next batch production application process. The method for testing the low-magnetic heading error of an atomic magnetometer in an external field provided by the present invention can solve the problems of changeable geomagnetic field direction, large fluctuations in the magnetic field environment and low efficiency of manual calibration in the process of heading error calibration of an atomic magnetometer in the prior art. The system design avoids the residual magnetic interference of the test equipment itself, maximizes the high sensitivity of the atomic magnetometer, and provides an effective automated calibration method for the atomic magnetometer to adapt to different external field magnetic field environments and improve the environmental adaptability of heading error calibration. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The included drawings are used to provide a further understanding of the embodiments of the present invention, which constitute a part of the specification, are used to illustrate the embodiments of the present invention, and together with the text description, explain the principles of the present invention. Obviously, the drawings in the following description are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0015] Figure 1 A schematic diagram of an automated process of a method for testing an atomic magnetometer's low magnetic heading error in an external field according to a specific embodiment of the present invention is shown;

[0016] Figure 2 A schematic diagram of the composition of an atomic magnetometer external field low magnetic heading error test system provided according to a specific embodiment of the present invention is shown. DETAILED DESCRIPTION

[0017] It should be noted that, in the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0019] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0020] like Figure 1As shown, according to an atomic magnetometer external field low magnetic heading error test method, the atomic magnetometer external field low magnetic heading error test method includes: setting a skylight, a calibration turntable, a universal transmission rod and a turntable control system, the turntable control system includes a control computer and a three-channel servo motor, the calibration turntable includes a reference magnetometer fixture, a magnetometer to be tested fixture, a three-axis turntable, a level and a three-axis magnetic resistance; using the skylight to provide shielding for the heading error test to ensure the test continuity after the test is powered on; using the magnetometer to be tested fixture to fix the magnetometer to be tested on the three-axis turntable, using the reference magnetometer fixture to fix the reference magnetometer on the outside of the three-axis turntable, providing a reference magnetic field for the magnetometer to be tested during the calibration test process, The magnetic field signals of the magnetometer to be tested and the reference magnetometer are phase-differenced to eliminate the influence of common magnetic field interference sources in the external field on the magnetic field; when installing the calibration turntable, the level installed in the calibration turntable needs to be used to stably install the three-axis turntable on the ground to provide a stable environment for magnetometer debugging; after installing the two magnetometers on the three-axis turntable, the direction of the geomagnetic field is identified with the help of the three-axis magnetic resistance, and the three-axis turntable is rotated to align the sensitive axis of the atomic magnetometer with the direction of the geomagnetic field to avoid the influence of the geomagnetic field inclination on the test results; the three-axis turntable is connected to the three-channel servo motor by a universal transmission rod, and the action of the three-channel servo motor is transmitted to the three-axis turntable; the automatic test of the low magnetic heading error of the atomic magnetometer in the external field is completed by using the automated test process in the control computer.

[0021] By using this configuration, a method for testing the low-magnetic heading error of an atomic magnetometer in an outdoor field is provided. The method includes a canopy, a calibration turntable, a universal transmission rod, and a turntable control system. The magnetometer to be tested and the reference magnetometer are installed in the calibration turntable. The two magnetometers are differentially used to eliminate the fluctuation of the environmental magnetic field, avoiding various environmental interferences in the outdoor test environment, and improving the environmental applicability and robustness. The turntable control system controls the three-axis rotation direction of the turntable through the universal transmission rod, as well as the necessary rotation movements required for the heading error test. The heading error test is realized through a fixed process. The canopy used is used to provide the test system with the necessary rain protection capability to improve environmental adaptability. Due to the different geomagnetic inclinations in different use environments, the three-axis turntable integrates the three-axis magnetic resistance to effectively solve the specific environmental applicability in the heading error calibration process. The servo motor is used to automatically control the three-axis rotation process, realizing the automatic calibration process of the heading error of the atomic magnetometer, and improving the test efficiency of the atomic magnetometer in the next batch production application process. The method for testing the low-magnetic heading error of an atomic magnetometer in an external field provided by the present invention can solve the problems of changeable geomagnetic field direction, large fluctuations in the magnetic field environment and low efficiency of manual calibration in the process of heading error calibration of an atomic magnetometer in the prior art. The system design avoids the residual magnetic interference of the test equipment itself, maximizes the high sensitivity of the atomic magnetometer, and provides an effective automated calibration method for the atomic magnetometer to adapt to different external field magnetic field environments and improve the environmental adaptability of heading error calibration.

[0022] Furthermore, in the present invention, the automatic test of the low magnetic heading error of the atomic magnetometer external field is completed by using the automated test process in the control computer, which specifically includes: defining the sensitivity direction of the atomic magnetometer as the y direction, the direction sensitive to the rolling action as the x direction, and the direction sensitive to the heading action as the z direction; dividing the full range of the magnetic field in the z direction of the atomic magnetometer into 11 positions, and the servo motor uses the universal transmission shaft to rotate the heading action by ±60° at each position, and records the differential magnetic field of the two magnetometers at the same time, taking the position with the minimum bias change of the differential magnetic field data in the 11 positions, taking the two adjacent positions of the minimum position as the upper and lower limits, and evenly taking 21 positions again, and rotating the heading action by ±60° at each position again, synchronously recording the differential magnetic field data, and taking the position with the minimum bias change of the differential magnetic field as the magnetic field compensation value in the z direction; after the heading position of the magnetometer is returned to zero, dividing the full range of the magnetic field in the y direction of the atomic magnetometer into 11 positions, and the servo motor uses the universal transmission shaft to rotate the heading action by ±60° at each position, and records the differential magnetic field of the two magnetometers at the same time, and taking 11 positions. The minimum position of the differential magnetic field data bias change is set in the center, and the two adjacent positions of the minimum position are used as the upper and lower limits. 21 positions are evenly selected again, and the heading action is rotated ±60° at each position again. The differential magnetic field data is recorded synchronously, and the position with the minimum difference in the magnetic field bias change is taken as the magnetic field compensation value in the y direction. After the heading position of the magnetometer is returned to zero, the full range of the magnetic field in the x direction of the atomic magnetometer is evenly divided into 11 positions. The servo motor uses the universal transmission shaft to perform a rolling action and rotate ±60° at each position. At the same time, the differential magnetic field of the two magnetometers is recorded and taken. The position with the minimum bias change of the differential magnetic field data in the 11th position is taken as the upper and lower limits, and the 21st position is evenly taken again. The rolling action at each position is rotated ±60° again, and the differential magnetic field data is recorded synchronously. The position with the minimum bias change of the differential magnetic field is taken as the magnetic field compensation value in the x-direction; the rolling direction is set to zero, and the servo motor controls the three-axis turntable to rotate the sensitive axis direction of the atomic magnetometer 180°. Repeat the above steps to test again, output two sets of magnetometer compensation values, and complete the low magnetic heading error test of the atomic magnetometer in the external field.

[0023] Furthermore, in the present invention, each part of the test method needs to be designed to be non-magnetic. The frame of the canopy uses a wave fiber or carbon fiber frame, the metal fixing structure of the canopy uses a titanium material, and the ground nails of the canopy use a plastic material. The three-axis turntable is manufactured using polyimide plastic material, and the fixed structure of the calibration turntable is fixed using plastic or nylon screws. The universal transmission rod is made of polytetrafluoroethylene and the like for overall processing and customization.

[0024] In addition, in the present invention, since the servo motor itself cannot completely eliminate magnetism, the universal transmission rod increases the distance between the calibration turntable and the three-axis servo motor to more than 2m. A Permalloy shell needs to be customized outside the servo motor to shield the servo motor's own magnetic field. The Permalloy shell needs to be demagnetized with a large current before use. The distance between the control computer and the calibration turntable is greater than or equal to 5m.

[0025] According to another aspect of the present invention, Figure 2 As shown, an atomic magnetometer external field low magnetic heading error test system is provided, and the atomic magnetometer external field low magnetic heading error test system uses the atomic magnetometer external field low magnetic heading error test method described above to perform heading error test.

[0026] Furthermore, in the present invention, the atomic magnetometer external field low magnetic heading error test system includes a canopy, a calibration turntable, a universal transmission rod and a turntable control system, the turntable control system includes a control computer and a three-channel servo motor, the calibration turntable includes a reference magnetometer fixture, a magnetometer to be tested fixture, a three-axis turntable, a level and a three-axis magnetic resistance, the canopy is used to provide shielding for the heading error test to ensure the test continuity after the test is powered on, the magnetometer to be tested fixture is used to fix the magnetometer to be tested on the three-axis turntable, and the reference magnetometer fixture is used to fix the reference magnetometer on the outside of the three-axis turntable to provide a magnetometer to be tested during the calibration test process. A reference magnetic field is provided in the test, and the magnetic field signals of the magnetometer to be tested and the reference magnetometer are phase-differenced to eliminate the influence of common magnetic field interference sources in the external field on the magnetic field; the level is used to stably install the three-axis turntable on the ground to provide a stable environment for magnetometer debugging; the three-axis magnetic resistance is used to identify the direction of the geomagnetic field, and the three-axis turntable is rotated to align the sensitive axis of the atomic magnetometer with the direction of the geomagnetic field to avoid the influence of the geomagnetic field inclination on the test results; the universal transmission rod is used to connect the three-axis rotation mechanism of the three-axis turntable with the three-channel servo motor, and transmit the action of the three-channel servo motor to the three-axis turntable, and the control computer is used to complete the automatic test of the low magnetic heading error of the atomic magnetometer in the external field.

[0027] In order to further understand the present invention, the following Figure 1 and Figure 2 The method and system for testing the low magnetic heading error of an atomic magnetometer in an external field provided by the present invention are described in detail.

[0028] like Figure 1 and Figure 2As shown, the present invention provides a method for testing the low magnetic heading error of an atomic magnetometer in an external field. The method includes a canopy, a calibration turntable, a universal transmission rod and a turntable control system. The magnetometer to be tested and the reference magnetometer are installed in the calibration turntable. The two magnetometers are differentially used to eliminate environmental magnetic field fluctuations. The turntable control system controls the three-axis rotation direction of the turntable through the universal transmission rod, as well as the necessary rotation actions required for the heading error test. The heading error test is achieved through a fixed process. The canopy is used to provide the test system with the necessary rain protection capability and improve environmental adaptability. The sensitivity of the current mainstream scalar atomic magnetometer is close to 1pT / Hz. 1 / 2 The current situation of magnitude, compared with the heading error calibration of magnetic sensors in traditional aircraft, automobiles, ships and AR enhancement, the residual magnetism requirements are more stringent. In this method, each component is strictly designed to be non-magnetic, and the residual magnetism of each component must be less than 1nT. The technical solution of the present invention is applied to solve the problem that the existing heading error calibration method is not suitable for the increasingly high-sensitivity atomic magnetometer research and development, design, and production needs, and provides an effective automated calibration method for the atomic magnetometer to adapt to different external field magnetic field environments and improve the environmental adaptability of heading error calibration.

[0029] The present invention provides a method for testing the low-magnetic heading error of an atomic magnetometer in an external field, which can solve the problems of variable geomagnetic field direction, large fluctuations in the magnetic field environment and low efficiency of manual calibration in the calibration process of the heading error of the atomic magnetometer in the prior art, and the system design avoids the residual magnetic interference of the test equipment itself, and maximizes the high sensitivity of the atomic magnetometer. The method includes a skylight with a non-magnetized design, a calibration turntable, a universal transmission rod and a turntable control system, and cooperates with the necessary automatic calibration process for the heading error. The magnetometer to be tested, the three-axis magnetic resistance of the reference magnetometer and the level are installed in the calibration turntable, and the turntable control system rotates the three rotating axes of the calibration turntable through the universal transmission rod, and cooperates with the automated test process to complete the calibration of the heading error of the atomic magnetometer.

[0030] Furthermore, each part of the test method needs to be designed to be non-magnetized. The canopy used to provide sunlight and rain protection for the test method device is different from the traditional canopy. The frame should use a wave fiber or carbon fiber frame. The necessary metal fixing structure is recommended to use titanium metal material, and it should be cleaned in time after processing and manufacturing to avoid ferromagnetic material residue. The ground nails used to fix the canopy should be made of plastic. The existence of the canopy provides necessary shelter for the heading error test device to adapt to the rainy environment in the south, ensuring the continuity of the test after the test is powered on. The main structure of the calibration turntable is processed and manufactured with plastic materials such as polyimide, and the necessary fixing structure should be fixed with plastic or nylon screws. The universal transmission rod is a common mechanism. The single whole needs to be processed and customized with polytetrafluoroethylene, etc., to connect the three-axis rotation mechanism of the calibration turntable and the servo motor in the turntable control system, and transmit the servo motor action to the turntable. Since the servo motor itself cannot completely eliminate magnetism, the universal transmission rod needs to increase the distance between the calibration turntable and the servo motor to more than 2m. A Permalloy shell needs to be customized outside the servo motor to shield the servo motor's own magnetic field. The Permalloy shell needs to be demagnetized with a large current before use. The control computer part of the turntable control system is recommended to be at least 5m away from the calibration turntable. All parts involved need to undergo necessary residual magnetism tests before the device is built. The residual magnetism level is lower than 1nT to ensure that the test system as a whole is not magnetized.

[0031] Furthermore, the calibration turntable includes a reference magnetometer fixture, a magnetometer fixture to be tested, a three-axis turntable, a level and a three-axis magnetic resistance. The magnetometer fixture to be tested is used to fix the magnetometer to be tested and the three-axis turntable, and the reference magnetometer fixture is used to fix the reference magnetometer on the outside of the three-axis turntable to provide a reference magnetic field for the magnetometer to be tested during the calibration test. The magnetic field signals of the two magnetometers are phase-differenced to eliminate the influence of magnetic field interference sources such as air chambers, ships, power cables, etc. in the external field on the magnetic field, providing good environmental adaptability for the heading error test of the atomic magnetometer. Since the environmental fluctuations generated by various interference sources are usually above 100pT during the field test, eliminating environmental errors will help the calibration of the heading error of the atomic magnetometer to improve the accuracy by 10pT.

[0032] Furthermore, the calibration turntable must follow necessary procedures during installation. During installation, the level installed in the calibration turntable must be used to stably install the three-axis turntable on the ground to provide a stable environment for magnetometer debugging. After the two magnetometers are installed on the three-axis turntable, the direction of the geomagnetic field is identified with the help of the three-axis magnetic resistance, and the three-axis turntable is rotated to align the sensitive axis of the atomic magnetometer with the direction of the geomagnetic field to avoid the influence of the geomagnetic field inclination on the test results. Due to the significant difference in geomagnetic inclination between northern and southern China, the fusion of the three-axis turntable and the three-axis magnetic resistance helps this test method to be applicable to a variety of domestic field environments and increase its adaptability to specific field environments.

[0033] Furthermore, the control computer of the turntable control system contains necessary automated test processes to avoid the currently common manual calibration. During the test, taking the common scalar magnetometer as an example, the sensitivity direction of the atomic magnetometer is defined as the y direction, and the direction sensitive to the rolling action is the x direction, and the direction sensitive to the heading action is the z direction. The magnetic compensation range in each direction is ±3nT. After the segmented test, the final accuracy meets 30pT, which is close to the peak-to-peak value of the short-term drift of the differential magnetic field in the external field environment, meeting the requirements. The basis of magnetic compensation is that when the magnetometer has no heading error, when the magnetometer rotates, the residual magnetism in each direction will no longer affect the output of the magnetometer, otherwise it will cause the output magnetic field to be distorted. The specific calibration process is as follows: the magnetic field range of the atomic magnetometer in the z direction is divided into 10 segments, and the 11 positions are obtained after the test. The servo motor rotates the heading action by ±60° horizontally with the help of the universal transmission shaft, and the differential magnetic field of the two magnetometers is recorded at the same time. The position with the minimum change in the differential magnetic field data bias in the 11 positions is taken; the two adjacent positions of the minimum position are taken as the upper and lower limits, and the 21 positions are taken evenly again, and the heading direction is rotated by ±60° at each position again, and the differential magnetic field data is recorded synchronously, and the position with the minimum change in the differential magnetic field bias is taken as the z-direction magnetic field compensation value. After the heading position of the magnetometer is zeroed, the y-direction magnetic field is also divided into 11 positions and 21 positions in steps, and the heading action is rotated by ±60°, but the minimum peak-to-peak position of the differential magnetic field data is taken as the y-direction output value. After the heading position of the magnetometer is zeroed, the rolling action is rotated by ±60°, and after taking the 10th position and the 21st position in turn, the position with the minimum change in the differential magnetic field data bias is judged, and the x-direction magnetic field compensation value is output. Since the heading error of the atomic magnetometer is different when it is in the same direction or opposite direction as the geomagnetic field in actual application, after compensating for the residual magnetism in the x, y, and z directions, the sensitive axis direction of the atomic magnetometer is rotated 180° and tested again to improve the heading error test results.

[0034] In summary, the present invention provides a method for testing the low magnetic heading error of an atomic magnetometer in an external field, which satisfies the sensitivity requirement of 1pT / Hz by designing each component without magnetization. 1 / 2 Low-interference, high-precision heading error test of the horizontal atomic magnetometer. By using dual-head differential testing, various types of environmental interference in the field test environment are avoided, improving environmental applicability and robustness. Due to the different geomagnetic inclinations in different usage environments, the three-axis turntable integrates the three-axis magnetic resistance to effectively solve the specific environmental applicability of the heading error calibration process. The servo motor is used to automatically control the three-axis rotation process, which realizes the automated calibration process of the heading error of the atomic magnetometer and improves the test efficiency of the atomic magnetometer in the next batch production application process. It is worth noting that unlike the heading error calibration method of magnetic sensors in traditional aircraft, automobiles, ships and other fields, the 1pT / Hz of the atomic magnetometer 1 / 2Horizontal sensitivity means that traditional calibration methods and equipment (such as metal turntables and metal transmission mechanisms) are no longer applicable here, otherwise magnetic noise and residual magnetism will overwhelm the performance of the atomic magnetometer itself. The test methods based on the nT-level magnetic field resolution of the traditional magnetometer are no longer applicable. It is necessary and essential to completely redesign the heading error calibration. This technical solution is simple and easy to operate. Combining the high sensitivity of the atomic magnetometer, a complete heading error calibration system and method is designed, which can directly serve the production and manufacturing process of the atomic magnetometer, and provide a certain foundation for the next large-scale production and application of the atomic magnetometer.

[0035] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0036] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0037] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for testing the low magnetic heading error of an atomic magnetometer in an external field, characterized in that: The atomic magnetometer external field low magnetic heading error test method comprises: A canopy, a calibration turntable, a universal transmission rod and a turntable control system are provided, wherein the turntable control system includes a control computer and a three-channel servo motor, and the calibration turntable includes a reference magnetometer fixture, a magnetometer to be measured fixture, a three-axis turntable, a level and a three-axis magnetic resistance; The skylight is used to provide shielding for the heading error test to ensure the test continuity after the test is powered on; The magnetometer to be tested is fixed on the three-axis turntable by using the magnetometer to be tested fixing member, and the reference magnetometer is fixed on the outside of the three-axis turntable by using the reference magnetometer fixing member, so as to provide a reference magnetic field for the magnetometer to be tested during the calibration test process, and the magnetic field signals of the magnetometer to be tested and the reference magnetometer are phase-differenced to eliminate the influence of common magnetic field interference sources in the external field on the magnetic field; When installing the calibration turntable, the level gauge installed in the calibration turntable should be used to stably install the three-axis turntable on the ground to provide a stable environment for magnetometer debugging. After installing the two magnetometers on the three-axis turntable, the direction of the geomagnetic field is identified with the help of the three-axis magnetic resistance, and the three-axis turntable is rotated to align the sensitive axis of the atomic magnetometer with the direction of the geomagnetic field to avoid the influence of the geomagnetic field inclination on the test results. The three-axis turntable is connected to the three-channel servo motor by using the universal transmission rod, so as to transmit the motion of the three-channel servo motor to the three-axis turntable; The automatic test process in the control computer is used to complete the automatic test of the low magnetic heading error of the atomic magnetometer in the external field.

2. The method for testing the low magnetic field heading error of an atomic magnetometer according to claim 1, characterized in that: The automatic test process in the control computer is used to complete the automatic test of the low magnetic heading error of the atomic magnetometer in the external field, which specifically includes: Define the direction of atomic magnetometer sensitivity as y direction, the direction sensitive to rolling motion as x direction, and the direction sensitive to heading motion as z direction; The full range of the magnetic field in the z direction of the atomic magnetometer is evenly divided into 11 positions. The servo motor uses the universal transmission shaft to perform a heading action and rotate ±60° at each position. At the same time, the differential magnetic field of the two magnetometers is recorded. The position with the minimum bias change of the differential magnetic field data among the 11 positions is taken. The two adjacent positions of the minimum position are used as the upper and lower limits. 21 positions are evenly taken again. Each position is again rotated ±60° in the heading action. The differential magnetic field data is recorded synchronously. The position with the minimum bias change of the differential magnetic field is taken as the magnetic field compensation value in the z direction. After the heading position of the magnetometer is returned to zero, the full range of the magnetic field in the y direction of the atomic magnetometer is evenly divided into 11 positions. The servo motor uses the universal transmission shaft to perform a heading action rotation of ±60° at each position, and records the differential magnetic field of the two magnetometers at the same time. The position with the minimum bias change of the differential magnetic field data among the 11 positions is taken, and the two adjacent positions of the minimum position are used as the upper and lower limits. 21 positions are evenly taken again, and the heading action is rotated ±60° at each position again. The differential magnetic field data is recorded synchronously, and the position with the minimum bias change of the differential magnetic field is taken as the magnetic field compensation value in the y direction; After the heading position of the magnetometer is returned to zero, the full range of the magnetic field in the x-direction of the atomic magnetometer is evenly divided into 11 positions. The servo motor uses the universal transmission shaft to roll and rotate ±60° at each position, and records the differential magnetic field of the two magnetometers at the same time. The position with the minimum bias change of the differential magnetic field data among the 11 positions is taken, and the two adjacent positions of the minimum position are used as the upper and lower limits. 21 positions are evenly taken again, and each position is rolled and rotated ±60° again. The differential magnetic field data is recorded synchronously, and the position with the minimum bias change of the differential magnetic field is taken as the x-direction magnetic field compensation value; Set the roll direction to zero, and use the servo motor to control the three-axis turntable to rotate the sensitive axis of the atomic magnetometer 180°. Repeat the above steps to test again, output two sets of magnetometer compensation values, and complete the low-magnetic heading error test of the atomic magnetometer in the external field.

3. The method for testing the low magnetic field heading error of an atomic magnetometer according to claim 2, characterized in that: The frame of the canopy is made of wave fiber or carbon fiber frame, the metal fixing structure of the canopy is made of titanium metal material, and the ground nails of the canopy are made of plastic material.

4. The method for testing the low magnetic field heading error of an atomic magnetometer according to claim 3, characterized in that: The three-axis turntable is made of polyimide plastic material, and the fixing structure of the calibration turntable is fixed with plastic or nylon screws.

5. The method for testing the low magnetic field heading error of an atomic magnetometer according to claim 4, characterized in that: The universal transmission rod is integrally processed and customized using polytetrafluoroethylene or the like.

6. The method for testing the low magnetic field heading error of an atomic magnetometer according to claim 5, characterized in that: The universal transmission rod increases the distance between the calibration turntable and the three-axis servo motor to more than 2m.

7. The method for testing the low magnetic field heading error of an atomic magnetometer according to claim 6, characterized in that: The distance between the control computer and the calibration turntable is greater than or equal to 5m.

8. An atomic magnetometer external field low magnetic heading error test system, characterized in that: The atomic magnetometer external field low magnetic heading error test system uses the atomic magnetometer external field low magnetic heading error test method according to any one of claims 1 to 7 to perform a heading error test.

9. The atomic magnetometer external field low magnetic heading error test system according to claim 8, characterized in that: The atomic magnetometer external field low magnetic heading error test system comprises a canopy, a calibration turntable, a universal transmission rod and a turntable control system, wherein the turntable control system comprises a control computer and a three-channel servo motor, the calibration turntable comprises a reference magnetometer fixture, a magnetometer to be tested fixture, a three-axis turntable, a level and a three-axis magnetic resistance, the canopy is used to provide shielding for the heading error test to ensure the test continuity after the test is powered on, the magnetometer to be tested fixture is used to fix the magnetometer to be tested on the three-axis turntable, the reference magnetometer fixture is used to fix the reference magnetometer on the outside of the three-axis turntable to provide a reference magnetic field for the magnetometer to be tested during the calibration test, and the magnetic field signals of the magnetometer to be tested and the reference magnetometer are phase-differenced to eliminate the influence of common magnetic field interference sources in the external field on the magnetic field; The level is used to stably install the three-axis turntable on the ground to provide a stable environment for magnetometer debugging; the three-axis magnetic resistance is used to identify the direction of the geomagnetic field, and the three-axis turntable is rotated to align the sensitive axis of the atomic magnetometer with the direction of the geomagnetic field to avoid the influence of the geomagnetic field inclination on the test results; The universal transmission rod is used to connect the three-axis rotation mechanism of the three-axis turntable with the three-channel servo motor, and transmit the action of the three-channel servo motor to the three-axis turntable. The control computer is used to complete the automatic test of the low magnetic heading error of the atomic magnetometer in the external field.

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