Magnetic probe separation type high-precision magnetic compass

Abstract

The invention provides a high-precision magnetic compass with a separated magnetic probe. The magnetic compass comprises a magnetic probe plate and a mainboard which are connected through a cable to form a separated design; the magnetic compass has the following characteristics: the magnetic probe board and the main board both support 24 different installation modes, and can be randomly combined according to actual application scenes, so that the combination of 24 * 24 installation modes is realized, and the adaptability is greatly improved; at least 12 groups of magnetic field data under different attitudes are acquired, and various errors of the magnetic sensor are subjected to online adaptive calibration by using a Kalman filtering algorithm, so that the azimuth angle measurement precision is effectively improved; three-axis magnetic field data before and after calibration are linearly converted, data consistent with data in a standard 0-degree installation mode can be output, and additional calibration of an acceleration sensor on a mainboard is not needed.

Description

Technical Field

[0001] The invention belongs to the field of navigation technology, and in particular relates to a magnetic probe separated high-precision magnetic compass. Background Art

[0002] The earth is a natural magnet. The magnetic field lines of the geomagnetic field are all over the earth's surface. The geomagnetic field at every location on the earth's surface has a corresponding size and direction, so it is a natural navigation scale. As a passive autonomous pointing reference, the geomagnetic field has the advantages of strong anti-interference ability, high accuracy, and no cumulative error. The magnetic compass is developed based on the principle of geomagnetic north pointing. It is mainly composed of a three-axis magnetic sensor, a three-axis acceleration sensor, a power module, a signal processing module, and an interface circuit. It can be used to measure the carrier's azimuth, pitch angle, roll angle and other parameters. The magnetic azimuth relative to the local magnetic north directly output by the magnetic compass can be corrected by the magnetic declination to obtain the true north azimuth relative to the geographic north.

[0003] In a variety of single-person handheld observation devices, it is necessary to measure the azimuth, distance and other parameters of the target, so as to achieve long-distance positioning of the target. The magnetic compass has been widely used in this field due to its advantages of high precision, low power consumption and high cost performance. The magnetic compass has certain requirements for the magnetic environment at the installation position in the device. The magnetic sensor in the magnetic compass should be kept as far away as possible from objects with strong magnetic interference such as batteries and motors in the device to better play the performance of the magnetic compass. The development trend of single-person handheld observation equipment is to have higher and higher integration and smaller size. Therefore, the size requirements of the magnetic compass are getting higher and higher. It is necessary to design a magnetic probe separated high-precision magnetic compass to solve this problem. The three-axis magnetic sensor is designed on the magnetic probe board, and the rest is designed on another main board. The two circuit boards are connected by cables, which greatly reduces the size of the circuit board that has requirements for the magnetic environment of the installation position, so that it can be easier to find a suitable installation position in the single-person handheld device, and adapt to the application needs of the miniaturization development of single-person handheld observation equipment.

[0004] The development trend of single-person handheld observation equipment is to have higher and higher integration and smaller size. Therefore, the size requirements for magnetic compasses are getting higher and higher. It is necessary to design a high-precision magnetic compass with a magnetic probe separation to solve this problem. The three-axis magnetic sensor is designed on the magnetic probe board, and the rest is designed on another main board. The two circuit boards are connected by cables, which greatly reduces the size of the circuit board that has requirements on the magnetic environment of the installation location, making it easier to find a suitable installation location in a single-person handheld device, and adapting to the application needs of the miniaturization of single-person handheld observation equipment. Summary of the invention

[0005] In view of this, the present invention provides a high-precision magnetic compass with a separated magnetic probe, comprising the following steps:

[0006] Step 1: Design the three-axis magnetic sensor in the magnetic compass on a separate circuit board to obtain a magnetic probe board, and design the rest of the magnetic compass on another circuit board to obtain a main board. The magnetic probe board and the main board are connected by cables;

[0007] Step 2: The magnetic probe plate and the main board can be selected to include at least a first installation mode in which the coordinate systems of the magnetic probe plate and the main board completely coincide with the coordinate system of the carrier, a second installation mode in which the magnetic probe plate and the main board are rotated 90° around the Z axis, a third installation mode in which the magnetic probe plate and the main board are rotated 180° around the Z axis, and a fourth installation mode in which the magnetic probe plate and the main board are rotated 270° around the Z axis.

[0008] Step 3: According to the actual installation status of the magnetic probe board and the main board in the device, set the corresponding installation mode for the magnetic probe board and the main board respectively. According to the transformed installation mode, use the three-axis acceleration data on the main board to calculate the pitch angle and roll angle;

[0009] Step 4: Using the constructed mathematical model for magnetic interference compensation, when carrying out magnetic field space calibration, collect the three-axis magnetic sensor data and the corresponding pitch angle and roll angle after changing the installation mode in at least 12 different postures, solve the model, and calculate the three-axis magnetic field data after magnetic interference compensation after obtaining the model parameters;

[0010] Step 5: Use the three-axis magnetic field data after magnetic interference compensation and the corresponding pitch angle and roll angle to calculate the accurate azimuth angle of the carrier.

[0011] In particular, the magnetic compass in step 1 includes a three-axis magnetic sensor, a three-axis acceleration sensor, a power module, a signal processing module and an interface circuit.

[0012] In particular, in step 2, oxyz is the coordinate system of the carrier on which the magnetic compass is installed, the ox axis points to the forward direction of the carrier, the oy axis points to the right direction of the carrier, and the oz axis points downward; the coordinate system of the three-axis magnetic sensor on the magnetic probe board is o1x1y1z1, and the coordinate system of the three-axis acceleration sensor on the main board is o2x2y2z2.

[0013] In particular, in the first installation mode in step 2, the coordinate systems o1x1 and o2x2 are both parallel to ox and point in the same direction as the carrier's forward movement, o1y1 and o2y2 are both parallel to oy and point in the same direction as the right side of the carrier, and o1z1 and o2z2 are both parallel to oz and point downward; in the second installation mode, the coordinate systems o1y1 and o2y2 are both parallel to ox and point in the opposite direction to the carrier's forward movement, o1x1 and o2x2 are both parallel to oy and point in the same direction as the right side of the carrier, and o1z1 and o2z2 are both parallel to oz , pointing downward; in the third installation mode, the coordinate systems o1x1 and o2x2 are both parallel to ox and point opposite to the forward direction of the carrier, o1y1 and o2y2 are both parallel to oy and point opposite to the right side of the carrier, and o1z1 and o2z2 are both parallel to oz and point downward; in the fourth installation mode, the coordinate systems o1y1 and o2y2 are both parallel to ox and point in the same direction as the forward direction of the carrier, o1x1 and o2x2 are both parallel to oy and point opposite to the right side of the carrier, and o1z1 and o2z2 are both parallel to oz and point downward.

[0014] In particular, step 3 includes: for any installation posture, the original three-axis acceleration data can be equivalently converted into the first installation mode by adding negative signs or unchanged operations on the three components of xyz according to the corresponding relationship with the coordinate system of the first installation mode, so as to uniformly calculate the pitch angle and roll angle.

[0015] In particular, the magnetic field space calibration method for the constructed magnetic interference compensation model in step 4 is implemented by the following steps:

[0016] According to the Poisson model, a magnetic interference compensation calibration model for a magnetic compass is constructed. The above magnetic interference compensation model is transformed into a least squares optimization problem. By collecting at least 12 sets of magnetic field data under different postures, the Kalman filter algorithm is used to solve the calibrated three-axis magnetic field data.

[0017] Beneficial effects:

[0018] Through the technical solution of the present invention, the three-axis magnetic sensor is designed on the magnetic probe board, and the remaining parts are designed on another main board. The two circuit boards are connected by cables, which greatly reduces the size of the circuit board that has requirements on the magnetic environment of the installation position, making it easier to find a suitable installation position in a single-person handheld device, and adapting to the application needs of the miniaturization development of single-person handheld observation equipment.

[0019] Through the technical solution of the present invention, the magnetic probe board and the main board both support 24 different installation methods, and can be arbitrarily combined according to actual application scenarios to achieve a combination of 24×24 installation methods, greatly improving the adaptability and flexibility of the magnetic compass.

[0020] Through the technical solution of the present invention, at least 12 groups of magnetic field data in different postures are used in combination with the Kalman filter algorithm to perform online adaptive calibration on parameters such as sensitivity error, zero bias error, non-orthogonality error, hard magnetic interference and soft magnetic interference of the three-axis magnetic sensor, thereby effectively improving the azimuth measurement accuracy of the magnetic compass.

[0021] Through the technical solution of the present invention, the three-axis magnetic field data before and after calibration are converted through a linear model to achieve output data consistent with the "standard 0°" installation mode, without the need for additional calibration of the three-axis acceleration sensor on the mainboard, thereby simplifying the use process. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of a high-precision magnetic compass with a separated magnetic probe;

[0023] Figure 2 Define a schematic diagram for the carrier coordinate system;

[0024] Figure 3a-3d Schematic diagram of the relationship between the magnetic probe board coordinate system, the main board coordinate system and the carrier coordinate system under four installation methods;

[0025] Figure 4a-4d It is a schematic diagram of the relationship between the magnetic probe board coordinate system, the main board coordinate system and the carrier coordinate system under four installation methods when the Z axis is facing upward;

[0026] Figure 5a-5d It is a schematic diagram of the relationship between the magnetic probe plate coordinate system, the main board coordinate system and the carrier coordinate system under four installation methods when the X-axis is facing upward;

[0027] Figure 6a-6d It is a schematic diagram of the relationship between the magnetic probe plate coordinate system, the main board coordinate system and the carrier coordinate system under four installation methods when the X-axis is facing downward;

[0028] Figure 7a-7d It is a schematic diagram of the relationship between the magnetic probe board coordinate system, the main board coordinate system and the carrier coordinate system under four installation methods when the Y axis is facing upward;

[0029] Figures 8a-8d It is a schematic diagram of the relationship between the magnetic probe board coordinate system, the main board coordinate system and the carrier coordinate system under four installation methods when the Y axis is facing downward;

[0030] Fig. 9 It is a schematic diagram of the relationship between the coordinate system of the magnetic probe board when the "X-axis is 90° upward" is installed, the coordinate system of the main board when the "Y-axis is 180° upward" is installed, and the coordinate system of the carrier. DETAILED DESCRIPTION

[0031] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0032] The solution of the present invention provides a high-precision magnetic compass with a separated magnetic probe, comprising:

[0033] Step 1: Design the three-axis magnetic sensor in the magnetic compass on a separate circuit board to obtain a magnetic probe board, and design the rest of the magnetic compass on another circuit board to obtain a main board. The magnetic probe board and the main board are connected by cables;

[0034] The present invention provides a magnetic compass developed according to the principle of geomagnetic north pointing, which is mainly composed of a three-axis magnetic sensor, a three-axis acceleration sensor, a power module, a signal processing module and an interface circuit. The three-axis magnetic sensor is used to measure the three-axis direction magnetic field data, and the three-axis accelerometer is used to measure the three-axis direction acceleration data, and then calculate the azimuth, pitch angle and roll angle. In order to facilitate related debugging, the traditional magnetic compass usually designs all modules on a circuit board. When the magnetic compass is installed on the device, it is necessary to choose a location away from objects with strong magnetic interference such as batteries and motors on the device to minimize the impact of magnetic interference on the azimuth measurement accuracy of the magnetic compass. If the device size is small and the traditional magnetic compass size is relatively large, the traditional magnetic compass will not be well applied.

[0035] Step 2: The magnetic probe plate and the main board can be selected from at least a first installation mode of standard 0° in which the coordinate systems of the magnetic probe plate and the main board completely coincide with the coordinate system of the carrier, a second installation mode of standard 90° rotated 90° around the Z axis, a third installation mode of standard 180° rotated 180° around the Z axis, and a fourth installation mode of standard 270° rotated 270° around the Z axis;

[0036] The present invention adopts a magnetic probe and a mainboard separated design, and designs the traditional magnetic compass into a magnetic probe board and a mainboard, wherein only the three-axis magnetic sensor is on the magnetic probe board, and the rest are on the mainboard. The magnetic probe board and the mainboard are connected by a cable. A schematic diagram of a magnetic probe separated high-precision magnetic compass is shown in FIG. Figure 1 As shown in the figure, the coordinate system of the three-axis magnetic sensor on the magnetic probe board is o1x1y1z1, and the coordinate system of the three-axis acceleration sensor on the main board is o2x2y2z2.

[0037] Both the magnetic probe board and the main board support 24 installation methods that maintain a horizontal and vertical relationship with the carrier coordinate system. They can be arbitrarily combined according to the actual application scenario to achieve a combination of 24×24 installation methods. These 24 installation methods are named "standard 0°", "standard 90°", "standard 180°", "standard 270°"; "Z axis up 0°", "Z axis up 90°", "Z axis up 180°", "Z axis up 270°"; "X axis up 0°", "X axis up 90°", "X axis up 180°", "X axis up 270°"; "X axis down 0°", "X axis down 90°", "X axis down 180°", "X axis down 270°"; "Y axis up 0°", "Y axis up 90°", "Y axis up 180°", "Y axis up 270°"; "Y axis down 0°", "Y axis down 90°", "Y axis down 180°", "Y axis down 270°". The carrier coordinate system oxyz is defined as follows: Figure 2 shown.

[0038] When the magnetic probe board and the main board are both installed in the "standard 0°" mode, the relationship between the three-axis magnetic sensor coordinate system o1x1y1z1 on the magnetic probe board, the three-axis acceleration sensor coordinate system o2x2y2z2 on the main board and the carrier coordinate system oxyz is as follows: Figure 3a At this time, the magnetic sensor o1x1 and the acceleration sensor o2x2 are both parallel to ox and point in the same direction as the carrier's forward direction, the magnetic sensor o1y1 and the acceleration sensor o2y2 are both parallel to oy and point in the same direction as the right side of the carrier, and the magnetic sensor o1z1 and the acceleration sensor o2z2 are both parallel to oz and point downward.

[0039] When the magnetic probe board and the main board are both installed in the "standard 90°" mode, the relationship between the three-axis magnetic sensor coordinate system o1x1y1z1 on the magnetic probe board, the three-axis acceleration sensor coordinate system o2x2y2z2 on the main board and the carrier coordinate system oxyz is as follows: Figure 3b As shown. The magnetic sensor o1y1 and the acceleration sensor o2y2 are both parallel to ox and point in the opposite direction of the carrier's forward direction. The magnetic sensor o1x1 and the acceleration sensor o2x2 are both parallel to oy and point in the same direction as the right side of the carrier. The magnetic sensor o1z1 and the acceleration sensor o2z2 are both parallel to oz and point downward.

[0040] When the magnetic probe board and the main board are both installed in the "standard 180°" mode, the relationship between the three-axis magnetic sensor coordinate system o1x1y1z1 on the magnetic probe board, the three-axis acceleration sensor coordinate system o2x2y2z2 on the main board and the carrier coordinate system oxyz is as follows: Figure 3cAs shown. The magnetic sensor o1x1 and the acceleration sensor o2x2 are both parallel to ox and point in the opposite direction of the carrier's forward direction. The magnetic sensor o1y1 and the acceleration sensor o2y2 are both parallel to oy and point in the opposite direction of the right side of the carrier. The magnetic sensor o1z1 and the acceleration sensor o2z2 are both parallel to oz and point downward.

[0041] When the magnetic probe board and the main board are both installed in the "standard 270°" mode, the relationship between the three-axis magnetic sensor coordinate system o1x1y1z1 on the magnetic probe board, the three-axis acceleration sensor coordinate system o2x2y2z2 on the main board and the carrier coordinate system oxyz is as follows: Figure 3d As shown. The magnetic sensor o1y1 and the acceleration sensor o2y2 are parallel to ox and point in the same direction as the carrier's forward direction. The magnetic sensor o1x1 and the acceleration sensor o2x2 are parallel to oy and point in the opposite direction to the right side of the carrier. The magnetic sensor o1z1 and the acceleration sensor o2z2 are parallel to oz and point downward. In this way, the magnetic probe board and the main board can realize four installation modes: "standard 0°", "standard 90°", "standard 180°" and "standard 270°".

[0042] Similarly, "Z axis upward 0°", "Z axis upward 90°", "Z axis upward 180°", "Z axis upward 270°" can be realized. Figure 4a-4d As shown in the figure; "X axis upward 0°", "X axis upward 90°", "X axis upward 180°", "X axis upward 270°" as shown in the figure Figure 5a-5d As shown in the figure; "X axis downward 0°", "X axis downward 90°", "X axis downward 180°", "X axis downward 270°" as shown in the figure Figure 6a-6d As shown in the figure; "Y axis upward 0°", "Y axis upward 90°", "Y axis upward 180°", "Y axis upward 270°" as shown in the figure Figure 7a-7d As shown in the figure; "Y axis downward 0°", "Y axis downward 90°", "Y axis downward 180°", "Y axis downward 270°" as shown in the figure Figures 8a-8d The magnetic probe board and the main board can realize 24 kinds of installation methods by using the above method, and can be combined arbitrarily, so the magnetic probe board and the main board can realize 24×24 kinds of installation methods.

[0043] Step 3: According to the actual installation status of the magnetic probe board and the main board in the device, set the corresponding installation mode for the magnetic probe board and the main board respectively. According to the transformed installation mode, use the three-axis acceleration data on the main board to calculate the pitch angle and roll angle;

[0044] In step 3, make corresponding settings according to the actual installation methods of the magnetic probe board and the main board. Here, we take the installation method of the magnetic probe board as "X-axis upward 90°" and the main board as "Y-axis upward 180°" as an example. Fig. 9 As shown. Since the three-axis acceleration sensor on the mainboard is calibrated during factory debugging, the accuracy of the output of the three-axis acceleration sensor can be ensured. Installing it on the device will not affect the accuracy of its output, and it does not need to be calibrated again. At this time, the acceleration sensors o2x2 and ox on the mainboard are parallel to each other, pointing in the opposite direction of the carrier's forward movement, and their output value is g x , the acceleration sensor o2z2 is parallel to oy, pointing in the opposite direction to the right side of the carrier, and its output value is g z , the accelerometer o2y2 is parallel to oz, pointing upward, and its output value is g y The output value of o2x2 is negatively inverted to make it have the same direction as ox, then the transformed output G x =-g x ; Add a negative sign to the output value of o2z2 to make it have the same direction as oy, then the transformed output G y =-g z ; Add a negative sign to the output value of o2y2 to make it have the same direction as oz, then the transformed output G z =-g y This will set the three-axis acceleration output g of the motherboard in the "Y-axis upward 180°" installation mode. x , g y , g z Transformed to the three-axis acceleration output G under "standard 0°" x , G y , G z , and then according to formula (1), the current pitch angle and roll angle can be solved, where β is the pitch angle and γ is the roll angle.

[0045]

[0046] The magnetic sensors o1y1 and ox on the magnetic probe are parallel and point in the opposite direction of the carrier. The output value is m y , the magnetic sensor o1z1 is parallel to oy and points to the right side of the carrier. Its output value is m z , o1x1 is parallel to oz, pointing upward, and its output value is m x The output value of o1y1 is negatively inverted to make it have the same direction as ox. Then the output M after transformation is x =-m y ; The output value of o1z1 is in the same direction as oy, so the output M after transformation y =m z ; Add a negative sign to the output value of o1x1 to make it have the same direction as oz, then the transformed output M z =-m xIn this way, the three-axis magnetic field output m of the magnetic probe board in the "X-axis upward 90°" installation mode x 、m y 、m z Transformed to the three-axis magnetic field output M under the "standard 0°" x 、M y 、M z .

[0047] In addition to being affected by its own sensitivity error, zero bias error, and non-orthogonality error, the data of the three-axis magnetic sensor is also affected by the hard magnetic interference and soft magnetic interference on the device. Therefore, after the magnetic compass is installed on the device, calibration is required to eliminate the above errors and improve the accuracy of the azimuth of the magnetic compass.

[0048] Step 4: Using the constructed mathematical model for magnetic interference compensation, when carrying out magnetic field space calibration, collect the three-axis magnetic sensor data and the corresponding pitch angle and roll angle after changing the installation mode in at least 12 different postures, solve the model, and calculate the three-axis magnetic field data after magnetic interference compensation after obtaining the model parameters;

[0049] The three-axis magnetic field data before calibration obtained by the magnetic compass is mag a =[M x M y M z ] T , the three-axis magnetic field data obtained after calibration is mag b =[M x1 M y1 M z1 ] T , the magnetic interference compensation calibration model of the magnetic compass is constructed according to the Poisson model as shown in formula (2).

[0050] mag b =K(mag a +Z) (2)

[0051] Where K is the parameter matrix composed of the sensitivity error, non-orthogonality error, and soft magnetic interference of the three-axis magnetic sensor, and Z is the parameter matrix composed of the zero bias error and hard magnetic interference of the three-axis magnetic sensor.

[0052] After installing the magnetic compass on the device, use the above transformation method to transform the magnetic probe plate installation mode "X pointing up 90°" to the "standard 0°" state. Together with the device, carry out magnetic field space calibration in an area with uniform and stable environmental magnetic field. Collect at least 12 sets of data in different postures. The model can be solved by the following method.

[0053] Taking the second norm of formula (2), we can get formula (3):

[0054]

[0055] During the calibration process, the magnetic compass is placed in at least 12 positions in a fixed area to collect data. The magnetic field in this area || mag b || is a known value, solve the model parameters c1~c 10 Completed through Kalman filtering, c1~c 10 is the error parameter of the three-axis magnetic sensor, and the parameter matrix K, Z is composed of the error parameters c1~c 10 constitute.

[0056] The state vector of the Kalman filter is:

[0057] X=[c1 c2 c3 c4 c5 c6 c7 c8 c9 c 10 ] T

[0058] Formula (3) is used as the measurement equation of the Kalman filter, and the state transfer matrix of the Kalman filter is the unit matrix I.

[0059] After establishing the Kalman filter system state equation XI and the measurement equation, the basic equation of the Kalman filter solution process is shown in formula (4).

[0060]

[0061] In the formula, k is the number of times data is input during calculation, Q k-1 is the variance matrix of the noise sequence of the Kalman filter system; R k is the variance matrix of the measurement noise sequence; and P k-1 is the initial state estimate of the filter, Φ k,k-1 is the filter state transfer matrix, is the one-step prediction of the filtered state, P k / k-1 is the one-step prediction mean square error, K k is the Kalman filter gain, is the filter state estimate, P k is the state estimation error, Z k is the state quantity, namely ||mag b ||, H k is the measurement matrix, is the measurement equation. The measurement matrix H k From equation (3), we can get the measurement equation Contains c1~c 10 .

[0062] Given filter initial value and P0, collect at least twelve or more different postures of the magnetic compass three-axis magnetic field data Mx 、M y 、M z The data is input into the Kalman filter equation (4) to recursively calculate the state estimate at time k The estimated value of the Kalman filter state vector is obtained That is, the parameters c1~c that need to be solved 10 .

[0063] Get parameters c1~c 10 Then, substitute into (2) to obtain the calibrated three-axis magnetic field output value M x1 、M y1 、M z1 .

[0064] Step 5: Use the three-axis magnetic field data after magnetic interference compensation and the corresponding pitch angle and roll angle to calculate the accurate azimuth angle of the carrier.

[0065] Combined with the pitch angle β and roll angle γ calculated in real time by formula (1), the output M of the three-axis magnetic sensor in the "standard 0°" state of the carrier coordinate system can be calculated by formula (5). x1 、M y1 、M z1 Transform to the horizontal X-axis direction M in the standard coordinate system x2 , Y axis direction M y2 And the vertical Z axis direction M z2 Magnetic field data.

[0066]

[0067] Get the horizontal X-axis direction M in the standard coordinate system x2 , Y axis direction M y2 After that, the azimuth angle α can be solved according to formula (6).

[0068] α=-atan2(M y2 ,M x2 ) (6)

[0069] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

[0070] It is obvious to those skilled in the art that the embodiments of the present invention are not limited to the details of the above exemplary embodiments, and that the embodiments of the present invention can be implemented in other specific forms without departing from the spirit or basic features of the embodiments of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the embodiments of the present invention is limited by the attached claims rather than the above description, so it is intended to include all changes that fall within the meaning and scope of the equivalent elements of the claims in the embodiments of the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved. In addition, it is obvious that the word "comprising" does not exclude other units or steps, and the singular does not exclude the plural. Multiple units, modules or devices stated in the system, device or terminal claims can also be implemented by the same unit, module or device through software or hardware. The words first, second, etc. are used to indicate names, and do not indicate any particular order.

[0071] Finally, it should be noted that the above implementation modes are only used to illustrate the technical solutions of the embodiments of the present invention and are not intended to limit them. Although the embodiments of the present invention have been described in detail with reference to the above preferred implementation modes, those skilled in the art should understand that the technical solutions of the embodiments of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-precision magnetic compass with a magnetic probe separation, characterized in that: The steps include: Step 1: Design the three-axis magnetic sensor in the magnetic compass on a separate circuit board to obtain a magnetic probe board, and design the rest of the magnetic compass on another circuit board to obtain a main board. The magnetic probe board and the main board are connected by cables; Step 2: The magnetic probe plate and the main board can be selected to include at least a first installation mode in which the coordinate systems of the magnetic probe plate and the main board completely coincide with the coordinate system of the carrier, a second installation mode in which the magnetic probe plate and the main board are rotated 90° around the Z axis, a third installation mode in which the magnetic probe plate and the main board are rotated 180° around the Z axis, and a fourth installation mode in which the magnetic probe plate and the main board are rotated 270° around the Z axis. Step 3: According to the actual installation status of the magnetic probe board and the main board in the device, set the corresponding installation mode for the magnetic probe board and the main board respectively. According to the transformed installation mode, use the three-axis acceleration data on the main board to calculate the pitch angle and roll angle; Step 4: Using the constructed mathematical model for magnetic interference compensation, when carrying out magnetic field space calibration, collect the three-axis magnetic sensor data and the corresponding pitch angle and roll angle after changing the installation mode in at least 12 different postures, solve the model, and calculate the three-axis magnetic field data after magnetic interference compensation after obtaining the model parameters; Step 5: Use the three-axis magnetic field data after magnetic interference compensation and the corresponding pitch angle and roll angle to calculate the accurate azimuth angle of the carrier.

2. A high-precision magnetic compass with a separated magnetic probe as claimed in claim 1, characterized in that: The magnetic compass in step 1 includes a three-axis magnetic sensor, a three-axis acceleration sensor, a power module, a signal processing module and an interface circuit.

3. A high-precision magnetic compass with a separated magnetic probe as claimed in claim 2, characterized in that: In step 2, let oxyz be the coordinate system of the carrier on which the magnetic compass is installed, the ox axis points to the forward direction of the carrier, the oy axis points to the right direction of the carrier, and the oz axis points downward; the coordinate system of the three-axis magnetic sensor on the magnetic probe board is o1x1y1z1, and the coordinate system of the three-axis acceleration sensor on the main board is o2x2y2z2.

4. A high-precision magnetic compass with a separated magnetic probe as claimed in claim 3, characterized in that: In the first installation mode in step 2, the coordinate systems o1x1 and o2x2 are both parallel to ox and point in the same direction as the carrier's forward movement; o1y1 and o2y2 are both parallel to oy and point in the same direction as the carrier's right side; o1z1 and o2z2 are both parallel to oz and point downward; in the second installation mode, the coordinate systems o1y1 and o2y2 are both parallel to ox and point in the opposite direction to the carrier's forward movement; o1x1 and o2x2 are both parallel to oy and point in the same direction as the carrier's right side; o1z1 and o2z2 are both parallel to oz and point downward. downward; in the third installation mode, the coordinate systems o1x1 and o2x2 are both parallel to ox and point opposite to the forward direction of the carrier, o1y1 and o2y2 are both parallel to oy and point opposite to the right side of the carrier, and o1z1 and o2z2 are both parallel to oz and point downward; in the fourth installation mode, the coordinate systems o1y1 and o2y2 are both parallel to ox and point in the same direction as the forward direction of the carrier, o1x1 and o2x2 are both parallel to oy and point opposite to the right side of the carrier, and o1z1 and o2z2 are both parallel to oz and point downward.

5. A high-precision magnetic compass with a separated magnetic probe as claimed in claim 4, characterized in that: The step 3 includes: for any installation posture, the original three-axis acceleration data can be equivalently converted into the first installation mode by adding negative signs or keeping the three components xyz unchanged according to the corresponding relationship between the three components and the first installation mode, so as to uniformly calculate the pitch angle and the roll angle.

6. A high-precision magnetic compass with a separated magnetic probe as claimed in claim 5, characterized in that: The magnetic field space calibration method for the constructed magnetic interference compensation model in step 4 is implemented by the following steps: According to the Poisson model, a magnetic interference compensation calibration model for a magnetic compass is constructed. The above magnetic interference compensation model is transformed into a least squares optimization problem. By collecting at least 12 sets of magnetic field data under different postures, the Kalman filter algorithm is used to solve the calibrated three-axis magnetic field data.

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