Gain-adapting rigid body magnetometer attitude recording instrument

Abstract

The application discloses a rigid body attitude recording instrument with gain self-adaption, which comprises a magnetoresistance sensor, an operational amplifier circuit, a processor, a memory and a power supply. The magnetoresistance sensor is used for receiving a magnetic field signal of real-time motion of a rigid body, converting the magnetic field signal into an electric level output and outputting the electric level to the operational amplifier circuit. The operational amplifier circuit comprises an operational amplifier and a digital potentiometer. The digital potentiometer is used for changing a resistance value in real time to adapt to different magnetic field environments. The operational amplifier circuit is in communication connection with the processor. The processor is used for performing A / D conversion on a signal after operational amplification. The memory is used for storing data processed by the processor. The power supply supplies power for the recording instrument. The application overcomes the deficiency that a coil type magnetoresistance sensor cannot realize static measurement by means of hardware circuit design. The gain can be self-adaptively adjusted in the face of rigid bodies made of different materials, so that the measurement result is more accurate.

Description

Technical Field

[0001] This invention belongs to the field of rigid body attitude measurement, specifically a gain-adaptive magnetoresistive sensor rigid body attitude measurement recorder. Background Technology

[0002] The Earth's magnetic field exists in near-Earth space surrounding the Earth. Within a certain region, the magnetic field strength, magnetic declination, and magnetic inclination are fixed, thus the Earth's magnetic field can serve as a reference for the attitude of rigid bodies in flight. The geomagnetic attitude measurement method uses magnetoresistive sensors to measure these parameters and calculates and corrects the attitude of the flying object using a geomagnetic mathematical model. With the continuous improvement of geomagnetic theory, the technology of measuring rigid body attitude using magnetoresistive sensors has become increasingly mature. This method is not affected by long-term accumulated errors during integral calculation and has strong overload resistance. Other attitude measurement methods, such as solar azimuth sensor attitude measurement and satellite attitude measurement, have limitations in terms of testing environment and test objects, and the cost of the measuring devices used is too high. Common inertial device attitude measurement methods are also difficult to meet the requirements of attitude measurement in high-dynamic environments, and are prone to accumulated integral errors under long-term measurements. Of course, when using magnetoresistive sensors, the geomagnetic field signal is also very weak in some regions, requiring the use of operational amplifiers to amplify the signal. After amplification, the signal is converted by an A / D converter to obtain the real-time flight attitude of the rigid body. Magnetoresistive sensors and their operational amplifier circuits acquire analog signals. The capacitors and resistors surrounding the circuit need to be constantly adjusted according to the gain. However, when the recorder is fully assembled and used in various experiments, facing complex experimental environments and rigid bodies of different materials, it is impossible to replace the capacitors and resistors inside the recorder in real time to read the attitude of the rigid body during motion. Therefore, there is an urgent need to creatively develop a magnetoresistive sensor rigid body attitude measurement recorder that can meet the requirements of gain self-adaptation. Summary of the Invention

[0003] The purpose of this invention is to provide a gain-adaptive magnetoresistive sensor rigid body attitude measurement recorder to achieve real-time, low-cost, and complex-environment-compatible rigid body attitude measurement with different materials.

[0004] The technical solution to achieve the purpose of this invention is as follows:

[0005] An adaptive gain magnetoresistive sensor rigid body attitude measurement recorder includes a magnetoresistive sensor, an operational amplifier circuit, a processor, a memory, and a power supply. The magnetoresistive sensor receives the magnetic field signal from the real-time motion of the rigid body and converts the magnetic field signal into a level signal, which is then output to the operational amplifier circuit. The operational amplifier circuit includes an operational amplifier and a digital potentiometer. The digital potentiometer is used to change its resistance value in real time to adapt to different magnetic field environments, thereby achieving an adaptive gain effect for different rigid bodies and under different environments. The operational amplifier circuit is communicatively connected to the processor, which performs A / D conversion on the amplified signal. The memory stores the data processed by the processor. The power supply provides power to the magnetoresistive sensor, operational amplifier circuit, processor, and memory.

[0006] Furthermore, the magnetoresistive sensor includes a single-axis magnetoresistive sensor and a dual-axis magnetoresistive sensor. The single-axis magnetoresistive sensor is responsible for acquiring geomagnetic signals in the Z-axis direction, and the dual-axis magnetoresistive sensor is responsible for acquiring geomagnetic signals in the X and Y-axis directions.

[0007] Furthermore, the operational amplifier includes a first-stage operational amplifier circuit and a second-stage operational amplifier circuit. The first-stage operational amplifier circuit includes a single-channel integrated operational amplifier circuit and a dual-channel integrated operational amplifier circuit. The single-channel integrated operational amplifier circuit is responsible for initially amplifying the Z-axis signal data measured by the single-axis magnetoresistive sensor, and the dual-channel integrated operational amplifier is responsible for initially amplifying the X and Y-axis signal data measured by the dual-axis magnetoresistive sensor. The second-stage operational amplifier circuit is used to further amplify the signal output by the first-stage operational amplifier circuit.

[0008] Furthermore, the single-channel integrated operational amplifier circuit uses INA126, and the dual-channel integrated operational amplifier circuit uses INA2126. A variable resistor R20 is connected between pins 1 and 8 of the INA126. Both its V+IN and V-IN terminals use a parallel connection of resistor and capacitor. The V+IN terminal is connected to the Z-axis signal, which is then internally amplified and output to the secondary operational amplifier circuit via pin 6. The INA2126 is similar to the INA126. A forty-eighth resistor R48 is connected between pins 3 and 4, and a forty-ninth resistor R49 is connected between pins 13 and 14. Its V+INA, V-INA, V+INB, and V-INB terminals all use a parallel connection of resistor and capacitor. The V+INA and V+INB terminals are connected to the X and Y axis signals, respectively, which are then internally amplified and output to the secondary operational amplifier circuit via pins 6 and 11, respectively.

[0009] Furthermore, the secondary operational amplifier circuit uses an LTC6242 chip. Pins 1 and 2 of the LTC6242 are connected in parallel with the eighteenth resistor R18 and the fifty-third capacitor C53. Meanwhile, pin 2 is connected in series with the twenty-first resistor R21 and the twenty-fifth capacitor C25. The other end of the twenty-fifth capacitor C25 is connected to pin 6 of the INA2126. Pin 3 is connected to the twenty-fourth resistor R24. Pins 6 and 7 are connected in parallel with the thirty-fourth resistor R34 and the fifty-sixth capacitor C56. Meanwhile, pin 6 is connected in series with the thirty-first resistor R31 and the twenty-ninth capacitor C29. The other end of the twenty-ninth capacitor C29 is connected to pin 11 of the INA2126. Pins 10 and 11 are connected in parallel with the thirty-fifth resistor R35 and the fifty-seventh capacitor C57. Meanwhile, pin 11 is connected in series with the thirty-second resistor R32 and the thirtieth capacitor C30. The other end of the thirtieth capacitor C30 is connected to pin 6 of the INA2126. The connections of pins 5 and 12 are the same as those of pin 3.

[0010] Furthermore, the digital potentiometer uses an AD8403 chip. Pin 2 of the AD8403 chip is connected to one end of the fifteenth resistor R15, and the other end of the fifteenth resistor R15 is connected to pin 14 of the INA2126 chip. Pin 4 of the AD8403 chip is connected to one end of the seventeenth resistor R17, and the other end of the seventeenth resistor R17 is connected to pin 13 of the INA2126 chip. By controlling the resistance value of the fifteenth resistor R15, the forty-ninth resistor R49 between pins 13 and 14 of the INA2126 chip is controlled. Pin 24 is connected to one end of the tenth resistor R10, and the other end of the tenth resistor R10 is connected to the INA2126 chip. Pin 3 and pin 22 are connected to one end of the eighth resistor R8. The other end of the eighth resistor R8 is connected to pin 4 of the INA2126 chip. The resistance value of R10 is controlled to control the forty-eighth resistor R48 between pins 3 and 4 of the INA2126 chip. Pin 20 is connected to one end of the twelfth resistor R12. The other end of the twelfth resistor R12 is connected to pin 1 of the INA126 chip. Pin 18 is connected to one end of the fourteenth resistor R14. The other end of the fourteenth resistor R14 is connected to pin 8 of the INA126 chip. The resistance value of the fourteenth resistor R14 is controlled to control the variable resistor R20 between pins 1 and 8 of the INA126 chip.

[0011] Furthermore, the relationship between the variable resistor R20 and the gain is as follows:

[0012] G = 5 + 80 kΩ / R G

[0013] Wherein, the R G R20 is the gain, and G is the gain.

[0014] Furthermore, the processor uses a 32-bit microcontroller chip STM32F103C8T6, the memory uses an SST25VF032B flash memory chip, and the magnetoresistive sensor uses a Wheatstone bridge structure. The output level conforms to the following equation:

[0015] ε=sV cc B

[0016] Where s is the sensor sensitivity, B is the magnetic flux density in a certain sensitive direction, Vcc is the product's power supply voltage, and ε is the output level.

[0017] Furthermore, pin 1 of the AD8403 chip is connected to pin 18 PB0 of the processor as channel 1 of the A / D conversion.

[0018] Furthermore, the standard power supply voltage for the magnetoresistive sensor and operational amplifier circuit is 5V, and the standard power supply voltage for the processor and memory is 3.3V.

[0019] The significant advantages of this invention compared to existing technologies are:

[0020] (1) The magnetoresistive sensor selected in this recorder is an analog magnetoresistive sensor. When faced with the weakening of the magnetic field of the rigid shell, the gain can be adjusted in time to transmit the accurate analog signal to the processor. This is significantly better than the fixed gain of the digital magnetoresistive sensor and greatly reduces the measurement error.

[0021] (2) The digital potentiometer uses a software communication protocol to communicate with the main chip to control the resistance value on its own circuit, thereby controlling the resistance value on the first-stage operational amplifier circuit to meet the adaptive gain effect and perfectly adapt to different magnetic field environments and rigid bodies made of different metal materials. Attached Figure Description

[0022] Figure 1 This is a hardware block diagram of a gain-adaptive magnetoresistive sensor rigid body attitude measurement recorder.

[0023] Figure 2 Design a physical assembly diagram for the PCB board of a homemade recorder.

[0024] Figure 3 This is the circuit diagram of the first-stage operational amplifier for a magnetoresistive sensor.

[0025] Figure 4 This is the circuit diagram of the second-stage operational amplifier for a magnetoresistive sensor.

[0026] Figure 5 This is a circuit diagram of a digital potentiometer for a magnetoresistive sensor.

[0027] Figure 6 This is a flowchart of the system software. Detailed Implementation

[0028] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0029] Example 1

[0030] This embodiment provides a gain-adaptive magnetoresistive sensor rigid body attitude measurement recorder. The recorder includes a magnetoresistive sensor, an operational amplifier in an operational amplifier circuit, a processor, a memory, and a power supply. The operational amplifier is mainly used to amplify the geomagnetic signal measured by the magnetoresistive sensor.

[0031] Compared to similar sensors such as Hall elements, fluxgate magnetometers, and magnetic induction coils, magnetoresistive sensors offer advantages such as small size, high sensitivity, strong anti-interference capability, and low cost. Internally, they employ a Wheatstone bridge structure. In the presence of a magnetic field, changes in the bridge's resistive elements cause corresponding changes in the output voltage across the bridge terminals, thus measuring changes in the magnetic field. The output voltage level conforms to the following equation:

[0032] ε=sV cc B

[0033] Where s is the sensor sensitivity, B is the magnetic flux density in a certain sensitive direction, and V cc ε represents the power supply voltage of the product, and ε represents the output level.

[0034] The magnetoresistive sensor comprises two magnetoresistive sensors. Based on the measured attitude and mathematical model, it has three axes: X, Y, and Z. One single-axis magnetoresistive sensor is primarily responsible for acquiring geomagnetic signals along the Z-axis, while the other dual-axis magnetoresistive sensor is primarily responsible for acquiring geomagnetic signals along the X and Y axes.

[0035] The operational amplifier circuit comprises three parts: a first-stage operational amplifier, a second-stage operational amplifier, and digital potentiometers. Because the geomagnetic field signal is relatively weak, a single operational amplifier is insufficient, necessitating an additional stage to achieve different gains. The first-stage operational amplifier circuit includes a single-channel integrated operational amplifier and a dual-channel integrated operational amplifier. The single-channel integrated operational amplifier primarily amplifies the Z-axis signal data measured by the single-axis magnetoresistive sensor, while the dual-channel integrated operational amplifier primarily amplifies the X and Y-axis signal data measured by the dual-axis magnetoresistive sensor. The specific resistance values ​​of some resistors in the single-channel and dual-channel integrated operational amplifier circuits are controlled by digital potentiometers. These potentiometers communicate with the processor using the SPI communication protocol, allowing for real-time resistance adjustments to adapt to different magnetic field environments and rigid body materials during the first-stage operational amplification. The second-stage operational amplifier circuit further amplifies the signal output from the preceding first-stage amplifier circuit to achieve the final gain effect.

[0036] The digital potentiometer in the operational amplifier circuit establishes communication with the main control chip. By writing code, it controls the variable resistor between the amplifier head and tail pins of the operational amplifier circuit to achieve adaptive gain effects for different rigid bodies and different environments.

[0037] The processor uses a 32-bit microcontroller chip. The ARM is mainly responsible for A / D conversion of the amplified signal to facilitate the host computer to read the data in the memory.

[0038] The memory uses a high-capacity flash memory chip, which uses a communication protocol to save the data converted by the processor's AD conversion module.

[0039] The power supply primarily powers the processor, memory, magnetoresistive sensor, digital potentiometer, and two-stage operational amplifier circuit. Considering the ease of battery replacement after prolonged use, the rigid body measurement recorder uses an external battery.

[0040] This application can measure the magnetic field signal of a rigid body rotating at a low frequency in the air, and the real-time motion attitude can be obtained through software processing. For rigid bodies made of different metal materials, the recorder can self-adjust to magnetic field interference of varying intensities through its internal processor to achieve gain self-adaptation.

[0041] Example 2

[0042] Figure 1This is the overall design block diagram of a gain-adaptive magnetoresistive sensor rigid body attitude recorder. The circuit design of this device is mainly divided into two parts: analog and digital. The analog part includes the magnetoresistive sensor circuit and its integrated operational amplifier circuit; the magnetoresistive sensor is used to receive the magnetic field signal of the rigid body's real-time motion. The digital part mainly consists of flash memory chip circuitry. The magnetoresistive sensors used are Honeywell's HMC series chips, one single-axis HMC1051 and the other dual-axis HMC1052. The processor uses STMicroelectronics' STM32F103C8T6 32-bit microcontroller chip based on the Cortex-M3 core. The ARM is mainly responsible for A / D conversion of the amplified signal to facilitate subsequent data reading from the memory by the host computer. The memory uses Microchip's SST25VF032B flash memory chip. The flash memory chip uses the SPI communication protocol to save the data converted by the STM32's A / D conversion module. The power supply consists of three parts. The main STM32 microcontroller and flash memory chips are powered by a standard voltage of 3.3V, while the magnetoresistive sensor, digital potentiometer, and two-stage operational amplifier circuit are powered by a standard voltage of 5V. The rigid body measurement recorder uses an external battery, so the battery must be small, high-capacity, and provide stable power. A 9V dry cell battery is selected as the VIN for the entire system. An XC6206 chip is used to regulate the VIN to 5V, and then a 3.3V converter chip from the XC6206 is used to convert the 5V to 3.3V, thus powering all the modules of the system.

[0043] The basic process of data acquisition and storage is as follows: The magnetoresistive sensor converts the magnetic induction intensity information into an electrical level output. After being amplified by a two-stage amplifier circuit, the geomagnetic signal is sent to the STM32 chip. The STM32 chip integrates an AD conversion module. The chip sends a conversion signal to the AD conversion module at fixed intervals, sending the digitized electrical level information into a 512-byte buffer allocated in RAM. When the buffer is full, the data is written to the flash memory chip all at once, and then all the measurement data is saved through the flash memory chip. A power supply provides power to the entire device.

[0044] Figure 2 The physical assembly diagram of the PCB board for the self-made recorder is designed. This measuring device integrates two sensor chips onto a single PCB board. The positions of the sensor chips must conform to the coordinate axes established by the rigid body mathematical model corresponding to the X, Y, and Z axes, so as to perfectly simulate and measure the rigid body's attitude. Figure 2The U3 and U6 chips are the locations of the sensor chips. Considering that the magnetoresistive sensor measures a weak geomagnetic signal and is easily affected by noise interference, the PCB layout and component placement strictly adhere to PCB design specifications. Many circuit pins utilize RC coupling to filter and eliminate interference. The placement of the positioning holes also needs to be considered in the PCB design. They are placed at the four corners of the circular board, which does not affect the main circuit wiring and facilitates installation within the black circular housing designed later. The entire black circular device can also be easily installed at the rear of the rigid body. Considering the need for future testing at a test range to verify the overload resistance, potting compound needs to be injected into these four positioning holes. The four small circular holes in the diagram indicate the specific locations of the positioning holes.

[0045] Figure 3 This is the first-stage operational amplifier circuit for the magnetoresistive sensor. The first-stage operational amplifier circuit uses the high-precision, low-power dual-output operational amplifier INA2126 and the single-output operational amplifier INA126 from IT Company. The V+IN and V-IN pins of the INA126 are both connected in parallel with a 24K resistor and a 4.7μF capacitor, which is a resistor-capacitor coupling method. The external variable resistor R is located between pins 1 and 8. G The resistance value is affected by the amplification gain. According to the formula G = 5 + 80kΩ / R G The variable resistance R20 (i.e., resistance R) can be calculated. G The INA126's pin 3 connects to the HMC1051Z's VO+, receiving the Z-axis signal. This signal is then internally amplified and output to the next stage of the amplifier circuit via pin 6. The INA2126 works similarly; its pins 2 and 15 connect to the HMC1052's OUT+, and pin 1 connects to OUT-, corresponding to receive the X and Y axis signals from the magnetoresistive sensor. The internal amplification then outputs the signal to the next stage of the amplifier circuit via pins 6 and 11.

[0046] Figure 4This is a two-stage operational amplifier circuit for a magnetoresistive sensor. The principle of a two-stage operational amplifier circuit is to use the output of the first-stage amplifier as the input of the second-stage operational amplifier, and then use the output of the second-stage amplifier for other circuits. The amplification factor is: first-stage amplification factor * second-stage operational amplification factor. For example, if a signal needs to be amplified by 600 times, but due to the limitations of the components (whether operational amplifiers or transistors), such as the first-stage amplifier amplifying it by 40 times, then the second-stage operational amplifier circuit needs to amplify it by 15 times. The two stages of amplifier circuits are cascaded to achieve 600 times amplification. The second-stage operational amplifier circuit uses the LTC6242 chip from Linear Technology Co., Ltd. It is responsible for further amplifying the signal output from the first-stage amplifier circuit. Pin 1 of the chip uses a 160K resistor R18 and a 22nF capacitor C53 connected in parallel, which are connected to pin 18 (PB0) of the main ARM chip, serving as channel 1 for A / D conversion in the code. Pin 2 of the U9 chip is connected in series with a 24K resistor R21 (21st pin) and a 4.7μF capacitor C25 (25th pin). The other end is connected to pin 6 of the INA2126. Pin 3 is connected to a 24K resistor R24 ​​(24th pin). The other end of R24 is mainly connected between two resistors (6.8K and 3.3K). One end of the resistor is connected to +5V, and the other end is grounded. Pins 1, 2, 6, and 7 are connected in parallel with a 160K resistor R34 (34th pin) and a 4.7nF capacitor C56 (56th pin). Pin 6 is connected in series with a 24K resistor R31 (31st pin) and a 4.7μF capacitor C29 (29th pin). The other end of capacitor C29 is connected to pin 11 of the INA2126. Pins 10 and 11 are connected in parallel with a 160K resistor R35 (35th pin) and a 4.7nF capacitor C57 (57th pin). Pin 11 is also connected in parallel with... The 32nd resistor R32 (24KΩ) and the 30th capacitor C30 (4.7μF) are connected in series. The other end of the 30th capacitor C30 is connected to pin 6 of the INA126. Pins 5 and 12 are connected in the same way as pin 3. The 56th capacitors C56 and C57 on pins 7 and 10 are both 4.7nF. The difference from the 22nF capacitor on pin 1 is because the waveform on that channel was smaller during actual circuit debugging, so its value was increased. The other two capacitors only need 4.7nF. Since only three signals are amplified, pins 14, 15, and 16 of the U9 chip are spares and can be connected normally.

[0047] Figure 5This is a circuit diagram for a digital potentiometer, using the AD8403 chip from Analog Devices (ADI). The resistance values ​​on this chip primarily control the resistance values ​​of a portion of the operational amplifier circuit, enabling adaptive gain for rigid bodies of different materials and under varying magnetic field environments. Pin 2 of the AD8403 chip (U5 in the image) is first connected to the 15th resistor R15, then to pin 14 of the INA2126 chip (U13 in the image). Pin 4 of the U5 chip is first connected to the 17th resistor R17, with the other end connected to pin 13 of the U13 chip. The resistance value of R15 is controlled via the SPI communication protocol to control the 49th resistor R49 between pins 13 and 14 of the U13 chip. Pin 24 of the U5 chip is first connected to a tenth resistor R10, and the other end is connected to pin 3 of the U13 chip. Pin 22 of the U5 chip is first connected to an eighth resistor R8, and the other end is connected to pin 4 of the U13 chip. The resistance value of R10 is controlled via the SPI communication protocol to control the forty-eighth resistor R48 between pins 3 and 4 of the U13 chip. Pin 20 of the U5 chip is first connected to a twelfth resistor R12, and the other end is connected to pin 1 of the INA126 chip. Pin 18 of the U5 chip is first connected to a fourteenth resistor R14, and the other end is connected to pin 8 of the INA126 chip. The resistance value of R14 is controlled via the SPI communication protocol to control the variable resistor R20 between pins 1 and 8 of the INA126 chip. The gain in the main code is G = 5 + 80kΩ / R. G The gain G(R) can be calculated. G (R20). That is, it can self-adjust when performing attitude measurement on rigid bodies with different geomagnetic environments and different metal materials.

[0048] Figure 6 This is the system software flowchart. The software driver sequentially controls and completes functions such as system chip initialization, AD data reading and conversion, and storage. After the system powers on, each module initializes, mainly including the STM32 processor, high-order timer, SPI1_FLASH (SST25 flash memory chip), SPI2_FLASH (digital potentiometer), geomagnetic ADC sampling, and USART. The magnetoresistive sensor reads the geomagnetic field data, which is then amplified by the operational amplifier circuit and sent to the STM32 main chip for A / D conversion. The data is then saved through the SST25 memory chip and subsequently read from the host computer via a serial port.

[0049] This recorder overcomes the limitations of previous coil-type magnetoresistive sensors, which could not perform static measurements, through hardware circuit design of the magnetoresistive sensor, operational amplifier, and digital potentiometer. It can also adaptively adjust the gain for rigid bodies of different materials, resulting in more accurate measurement results.

Claims

1. A gain-adaptive magnetoresistive sensor rigid body attitude measurement recorder, characterized in that: The system includes a magnetoresistive sensor, an operational amplifier circuit, a processor, a memory, and a power supply. The magnetoresistive sensor receives magnetic field signals from the real-time motion of a rigid body and converts these signals into an electrical level, which is then output to the operational amplifier circuit. The operational amplifier circuit includes an operational amplifier and a digital potentiometer. The digital potentiometer is used to change its resistance in real time to adapt to different magnetic field environments. The operational amplifier circuit is communicatively connected to the processor, which performs A / D conversion on the amplified signal. The memory stores the data processed by the processor. The power supply provides power to the magnetoresistive sensor, the operational amplifier circuit, the processor, and the memory. The magnetoresistive sensor includes a single-axis magnetoresistive sensor and a dual-axis magnetoresistive sensor. The single-axis magnetoresistive sensor is responsible for acquiring geomagnetic signals in the Z-axis direction, and the dual-axis magnetoresistive sensor is responsible for acquiring geomagnetic signals in the X and Y-axis directions. The operational amplifier includes a first-stage operational amplifier circuit and a second-stage operational amplifier circuit. The first-stage operational amplifier circuit includes a single-channel integrated operational amplifier circuit and a dual-channel integrated operational amplifier circuit. The single-channel integrated operational amplifier circuit is responsible for initially amplifying the Z-axis signal data measured by the single-axis magnetoresistive sensor, and the dual-channel integrated operational amplifier is responsible for initially amplifying the X and Y-axis signal data measured by the dual-axis magnetoresistive sensor. The second-stage operational amplifier circuit is used to further amplify the signal output by the first-stage operational amplifier circuit. The single-channel integrated operational amplifier circuit uses INA126, and the dual-channel integrated operational amplifier circuit uses INA2126. A variable resistor R20 is connected between pins 1 and 8 of the INA126. Both its V+IN and V-IN terminals use a parallel resistor-capacitor configuration. The V+IN terminal is connected to the Z-axis signal, which is then internally amplified and output to the secondary operational amplifier circuit via pin 6. The INA2126 is similar to the INA126. A forty-eighth resistor R48 is connected between pins 3 and 4, and a forty-ninth resistor R49 is connected between pins 13 and 14. Its V+INA, V-INA, V+INB, and V-INB terminals all use a parallel resistor-capacitor configuration. The V+INA and V+INB terminals are connected to the X and Y axis signals, respectively, which are then internally amplified and output to the secondary operational amplifier circuit via pins 6 and 11, respectively. The second-stage operational amplifier circuit uses the LTC6242 chip. Pins 1 and 2 of the LTC6242 are connected in parallel with the eighteenth resistor R18 and the fifty-third capacitor C53. Meanwhile, pin 2 is connected in series with the twenty-first resistor R21 and the twenty-fifth capacitor C25. The other end of the twenty-fifth capacitor C25 is connected to pin 6 of the INA2126. Pin 3 is connected to the twenty-fourth resistor R24. Pins 6 and 7 are connected in parallel with the thirty-fourth resistor R34 and the fifty-sixth capacitor C56. Meanwhile, pin 6 is connected in series with the thirty-first resistor R31 and the twenty-ninth capacitor C29. The other end of the twenty-ninth capacitor C29 is connected to pin 11 of the INA2126. Pins 10 and 11 are connected in parallel with the thirty-fifth resistor R35 and the fifty-seventh capacitor C57. Meanwhile, pin 11 is connected in series with the thirty-second resistor R32 and the thirtieth capacitor C30. The other end of the thirtieth capacitor C30 is connected to pin 6 of the INA2126. The connections of pins 5 and 12 are the same as those of pin 3. The digital potentiometer uses an AD8403 chip. Pin 2 of the AD8403 chip is connected to one end of the fifteenth resistor R15, and the other end of the fifteenth resistor R15 is connected to pin 14 of the INA2126 chip. Pin 4 of the AD8403 chip is connected to one end of the seventeenth resistor R17, and the other end of the seventeenth resistor R17 is connected to pin 13 of the INA2126 chip. By controlling the resistance value of the fifteenth resistor R15, the forty-ninth resistor R49 between pins 13 and 14 of the INA2126 chip is controlled. Pin 24 is connected to one end of the tenth resistor R10, and the other end of the tenth resistor R10 is connected to pin 14 of the INA2126 chip.

3. Pin 22 is connected to one end of the eighth resistor R8, and the other end of the eighth resistor R8 is connected to pin 4 of the INA2126 chip. The forty-eighth resistor R48 between pins 3 and 4 of the INA2126 chip is controlled by controlling the resistance value of the tenth resistor R10. Pin 20 is connected to one end of the twelfth resistor R12, and the other end of the twelfth resistor R12 is connected to pin 1 of the INA126 chip. Pin 18 is connected to one end of the fourteenth resistor R14, and the other end of the fourteenth resistor R14 is connected to pin 8 of the INA126 chip. The variable resistor R20 between pins 1 and 8 of the INA126 chip is controlled by controlling the resistance value of the fourteenth resistor R14. The processor uses a 32-bit microcontroller chip STM32F103C8T6, the memory uses an SST25VF032B flash memory chip, and the magnetoresistive sensor uses a Wheatstone bridge structure. The output level conforms to the following equation: Where s is the sensor sensitivity, B is the magnetic flux density in a certain sensitive direction, and V cc The power supply voltage for the product, This represents the output level.

2. The gain-adaptive magnetoresistive sensor rigid body attitude recorder according to claim 1, characterized in that: The relationship between the variable resistor R20 and the gain is as follows: G=5+80kΩ / R G Wherein, the R G R20 is the gain, and G is the gain.

3. The gain-adaptive magnetoresistive sensor rigid body attitude recorder according to claim 1, characterized in that: Pin 1 of the AD8403 chip is connected to pin 18 PB0 of the processor, serving as channel 1 for A / D conversion.

4. The gain-adaptive magnetoresistive sensor rigid body attitude measurement recorder according to any one of claims 1 to 3, characterized in that: The standard power supply voltage for the magnetoresistive sensor and operational amplifier circuit is 5V, while the standard power supply voltage for the processor and memory is 3.3V.

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