CN111964672A

CN111964672A - Inertia/geomagnetic combined navigation system low-noise measurement circuit based on three-axis TMR sensor

Info

Publication number: CN111964672A
Application number: CN202010791983.0A
Authority: CN
Inventors: 高艺成; 余强
Original assignee: Wuhan Likov Technology Co ltd
Current assignee: Wuhan Likov Technology Co ltd
Priority date: 2020-08-08
Filing date: 2020-08-08
Publication date: 2020-11-20
Anticipated expiration: 2040-08-08
Also published as: CN111964672B

Abstract

The invention relates to the technical field of navigation equipment circuits, in particular to a low-noise measurement circuit of an inertia/geomagnetic combined navigation system based on a three-axis TMR sensor, which comprises a power supply module, a signal processing module and an information acquisition module, wherein the power supply module comprises a +2.5V output power supply circuit, a +3.3V output voltage power supply circuit and a +5V buffer voltage power supply circuit; the information acquisition module comprises a triaxial tunneling magneto-resistive sensor circuit and an inertial sensor measuring circuit; the signal processing module comprises an X-axis signal processing circuit, a Y-axis signal processing circuit, a Z-axis signal processing circuit and an AD conversion circuit; the invention can make the underwater vehicle with a certain volume work for a longer time under water, and solve the problem that the noise of the signal at high frequency is not filtered thoroughly due to the lower frequency of the measuring magnetic field.

Description

Inertia/geomagnetic combined navigation system low-noise measurement circuit based on three-axis TMR sensor

Technical Field

The invention relates to the technical field of navigation equipment circuits, in particular to a low-noise measurement circuit of an inertia/geomagnetic combined navigation system based on a three-axis TMR sensor.

Background

Navigation positioning technology is in a basic position in the development of modern science and technology, permeates into various military and civil fields and plays an increasingly important role; with the continuous improvement of navigation requirements, a single navigation system cannot meet the current navigation requirements, so that the combined navigation system more and more highlights the technical advantages thereof, and common combined navigation systems include navigation modes such as inertia/GPS/geomagnetism and the like.

Because the GPS signal is quickly propagated and attenuated in water, when the unmanned underwater vehicle runs underwater, the inertial/GPS combined navigation system frequently unlocks a carrier target; compared with GPS navigation, geomagnetic navigation has small interference on signals, does not radiate energy externally, and has passivity; therefore, the application of inertia/geomagnetic combined navigation in the navigation system of the underwater unmanned underwater vehicle is a popular subject at present.

Tmr (tunnel magnetoresistive resistance) elements are a new type of magnetoresistive effect sensors that have started industrial applications in recent years, which use the tunnel magnetoresistive effect of magnetic multilayer film materials to sense a magnetic field; a Magnetic Tunnel Junction (MTJ) is also commonly used to refer to a TMR element; the MTJ comprises a free layer, a tunneling layer and a pinned layer, and is similar to a sandwich structure; the polarization direction of the free layer is influenced by the magnitude and direction of an external magnetic field; the tunneling layer is a thin non-ferromagnetic insulating layer; the pinned layer polarization direction is fixed by the coupling between the pinned layer and the antiferromagnetic layer; by changing the magnitude direction of the external magnetic field, the included angle between the polarization directions of the free layer and the pinned layer can be changed, the resistance value of the tunneling resistor is changed, and the corresponding resistor is called as tunneling magnetoresistance; the resistance value changes, namely TMR effect; the triaxial TMR sensor is designed into a Wheatstone bridge structure, so that the zero drift of the TMR sensor can be reduced, common-mode signals can be inhibited, and the circuit noise can be reduced.

The working principle of the MEMS accelerometer is that when the accelerometer and an external object do variable-speed motion, the mass block moves in the opposite direction under the action of inertia force; the displacement of the mass block is limited by the spring and the damper, and the external acceleration can be measured through the output voltage.

When the direction pointed by the rotating shaft of a rotating object is free from external force, the rotating shaft cannot be changed; according to the principle, the voltage is fixedly applied to the interior of the MEMS single-axis gyroscope and is changed alternately, so that one mass block can vibrate to move, when the mass block rotates, Coriolis acceleration can be generated, the measurement is performed at the moment, the angles of two directions of a single axis can be obtained, and the positions of six directions of the three axes can be measured by the three-axis MEMS gyroscope.

TMR2309 is a new generation of high performance tunnel magneto-resistance sensor, which adopts three unique push-pull Wheatstone full-bridge structure designs; the Wheatstone full bridge of each shaft provides differential voltage output, and the output has the advantages of good temperature stability, high sensitivity, wide dynamic range, wide working voltage range, low power consumption and the like.

MPU60X0 is the first nine-axis motion processing sensor that integrates a three-axis MEMS accelerometer, MEMS gyroscope, and an extensible digital motion processor that can be used to interface I2C with other digital sensors.

The underwater inertia/geomagnetic combined navigation method comprises the steps of obtaining carrier acceleration information through a three-axis accelerometer, obtaining carrier attitude information through a three-axis gyroscope, obtaining magnetic field intensity information through a tunneling magneto-resistance sensor, and solving navigation parameters such as the position and the speed of a carrier through a data fusion processing algorithm.

At present, an inertia/geomagnetic combined navigation detection circuit based on a TMR sensor is designed less, the research direction is wider, and the research can be carried out on the aspects of simplifying the circuit, reducing the power consumption, compressing the space size, reducing the design cost and the like; in order to enable an underwater vehicle with a certain volume to continuously work underwater for a longer time and solve the problem that noise filtering of signals at high frequency is not complete due to low frequency of a measuring magnetic field; therefore, the invention provides a detection circuit of an inertia/geomagnetic combined navigation system of a low-power-consumption and low-noise three-axis TMR sensor.

Disclosure of Invention

The invention aims to provide a low-noise measurement circuit of an inertia/geomagnetic combined navigation system based on a three-axis TMR sensor, so as to solve the problems in the prior art.

In order to achieve the purpose, the invention provides the following technical scheme: a low-noise measurement circuit of an inertia/geomagnetic combined navigation system based on a three-axis TMR sensor comprises a power supply module, a signal processing module and an information acquisition module, wherein the power supply module comprises a +2.5V output power supply circuit, a +3.3V output voltage power supply circuit and a +5V buffer voltage power supply circuit; the power supply circuit obtains +2.5V and +3.3V with small ripples through a +5V buffer power supply output circuit; the 2.5V output power circuit supplies power to the TMR sensor, the accelerometer and the IO interface power circuit; the +3.3V output voltage power supply circuit provides stable working voltage for the gyroscope;

the +5V buffer voltage power supply circuit includes: a power chip IC1, a first polarity capacitor chip Cp1, a second polarity capacitor Cp2, a patch port P1;

the 1 pin of the power chip IC1 is grounded; the positive electrode of the first polarity capacitor Cp1, the pin 3 of the power chip IC1 and one end of the patch port P1 are connected with the input of + 15V; pin 2 of the power chip IC2, and the anode of the second polarity capacitor Cp2 are connected with the output of +5V buffer voltage; the other end of the patch socket, the pin 1 of the power chip IC1, the other end of the first polarity capacitor Cp1 and the other end of the second polarity capacitor Cp2 are grounded; wherein, the power supply chip IC1 selects a low-voltage-stabilizing chip LM1117 with high voltage resistance and strong stability of NS company;

the +2.5V power output circuit comprises a power chip IC2, a third polar capacitor Cp3, a fourth polar capacitor Cp4, a first resistor R1 and a second resistor R2;

the pin 1 and the pin 3 of the power chip IC2 and the anode of the third polar capacitor Cp3 are connected with +5V buffer input voltage; the other end of the third polar capacitor Cp3 is grounded to pin 2 of the power chip IC 2; the pin 4 of the power chip IC2 is connected with one end of the first resistor R1 and one end of the second resistor R2, the other end of the second resistor R2 is grounded, and the other end of the first resistor R1 is connected with the pin 5 of the power chip IC2 and the positive electrode of the fourth polarity capacitor Cp 4; the other end of the fourth polarity capacitor Cp4 is connected with a TMR power supply; the power supply chip IC2 selects ADI low quiescent current LDO linear regulator ADP 7118;

the +3.3V output voltage circuit includes: a power chip IC3, a first nonpolar capacitor C1, a second nonpolar capacitor C2 and a third nonpolar capacitor C3;

one end of a pin 1 and a pin 3 of the power chip IC3 and one end of the first nonpolar capacitor are connected with a +5V output voltage power supply; the pin 4 of the power chip IC3 is connected with the second nonpolar capacitor C2 and the third nonpolar capacitor C3 to output voltage of + 3.3V; the pin 2 of the power chip IC3 is grounded to the other ends of the first nonpolar capacitor C1, the second nonpolar capacitor C2 and the third nonpolar capacitor C3; the power supply chip IC3 selects a reference voltage source chip RT9193 with high precision, low power consumption and low noise of RICHTEK company

The IO port voltage power supply circuit includes: a power chip IC4, a fifth polarity capacitor chip Cp5, a sixth polarity capacitor Cp 6;

the 1 pin of the power chip IC4 is grounded; the positive electrode of the fifth polarity capacitor Cp5 and the 3-pin of the power chip IC4 are connected with the input of + 5V; a pin 2 of the power chip IC2 and the anode of the sixth polar capacitor Cp6 are connected with the power voltage +2.5V output of the IO port; the pin 1 of the power chip IC4, the other end of the fifth polarity capacitor Cp5 and the other end of the sixth polarity capacitor Cp6 are grounded; wherein, the power supply chip IC4 selects a low-voltage-stabilizing chip LM1117 with high voltage resistance and strong stability of NS company.

Furthermore, the information acquisition module comprises a triaxial tunneling magneto-resistive sensor circuit and an inertial sensor measuring circuit, wherein the triaxial tunneling magneto-resistive sensor circuit converts the magnetic field intensity variation into an analog voltage quantity and then is connected to the signal processing circuit, and the inertial sensor measuring circuit directly outputs the measured information; the inertial sensor measuring circuit comprises an acceleration measuring circuit and a gyroscope measuring circuit;

the tri-axial tunneling magnetoresistive sensing circuit includes: the three-axis tunneling magneto-resistance sensor chip IC5, the fourth nonpolar capacitor C4 and the fifth nonpolar capacitor C5;

a pin 5 of the triaxial tunneling magneto-resistive sensor chip IC5 is connected with a section of a fourth nonpolar capacitor C4 and a fifth nonpolar capacitor C5 to output a +5V power supply voltage; the other ends of the fourth nonpolar capacitor C4 and the fifth nonpolar capacitor C5 and the 4 feet of the triaxial tunneling magneto-resistance sensor chip IC5 are grounded;

pins

3 and 6 of the three-axis tunneling magneto-resistance sensor chip IC5 are connected with X-axis magnetic field intensity output;

pins

2 and 7 of the three-axis tunneling magnetoresistive sensor chip IC5 are connected with Y-axis magnetic field intensity output;

pins

1 and 8 of the three-axis tunneling magnetoresistive sensor chip IC5 are connected with the output of the magnetic field intensity of the Z axis; the tri-axial tunneling magneto-resistance sensor chip IC5 is a TMR2309 chip with good temperature stability of Jiangsu multidimensional corporation.

Further, an inertia/geomagnetic combined navigation system low-noise measurement circuit based on a three-axis TMR sensor comprises: the accelerometer sensor chip IC6, a sixth nonpolar capacitor C6, a seventh nonpolar capacitor C7, an eighth nonpolar capacitor C8, a ninth nonpolar capacitor C9, a tenth nonpolar capacitor C10, an eleventh nonpolar capacitor C11, a twelfth nonpolar capacitor C12, a thirteenth nonpolar capacitor C13 and a patch port P2;

the 1 pin, the 2 pin, the 3 pin and the 4 pin of the acceleration sensor IC6 are connected with the 3 pin, the 4 pin, the 5 pin and the 6 pin of the socket P2; one end of a pin 5 of the acceleration sensor IC6, one end of a tenth nonpolar capacitor C10 and one end of an eleventh nonpolar capacitor C11 are connected with an IO port voltage power supply +2.5V output; the pin 8 of the acceleration sensor IC6 is connected with one end of a twelfth nonpolar capacitor C12 and one end of a thirteenth nonpolar capacitor C13; the other ends of the tenth nonpolar capacitor C10, the eleventh nonpolar capacitor C11, the twelfth nonpolar capacitor C12 and the thirteenth nonpolar capacitor C13 are grounded at the pin 6 of the acceleration sensor IC 6; the pin 10 of the acceleration sensor IC6 is connected to one end of a sixth nonpolar capacitor C6 and one end of a seventh nonpolar capacitor C7; one end of the 11 pin of the acceleration sensor IC6, one end of the eighth nonpolar capacitor C8 and one end of the ninth nonpolar capacitor C9 are connected with an IO port voltage power supply +2.5V output; the other ends of a pin 9 of the acceleration sensor IC6, a sixth nonpolar capacitor C6, a seventh nonpolar capacitor C7, an eighth nonpolar capacitor C8 and a ninth nonpolar capacitor C9 are grounded; the

pins

12, 13 and 14 of the acceleration sensor IC6 are connected with the

pins

7, 8 and 9 of the socket P2; the acceleration sensor IC6 is selected from an ADI three-axis MEMS digital accelerometer ADXL 355.

Further, the inertial/geomagnetic combined navigation system low-noise measurement circuit based on the three-axis TMR sensor comprises a sensing chip IC7, a fourteenth nonpolar capacitor C14, a fifteenth nonpolar capacitor C15, a sixteenth nonpolar capacitor C16 and a third patch socket P3;

the

pins

2, 3, 4, 5, 14, 15, 16, 17, 21 and 22 of the sensing chip IC7 are suspended; the

pins

6, 7, 9, 12, 23 and 24 of the sensing chip IC7 are connected with the

pins

5, 6, 7, 8, 3 and 4 of the third socket P3; one end of 8 pins and 13 pins of the sensing chip IC7 and one end of the fourteenth nonpolar capacitor C14 are connected with a +3.3V output voltage power supply; pin 10 of the sensing chip IC7 is connected to one end of the fifteenth nonpolar capacitor; the pin 20 of the sensing chip IC7 is connected with one end of the sixteenth non-polar capacitor;

pins

1, 11 and 18 of the sensing chip IC7 and the other ends of the fourteenth nonpolar capacitor C14, the fifteenth nonpolar capacitor C15 and the sixteenth nonpolar capacitor C16 are grounded; wherein the sensor chip IC7 is selected from the MPU6050 chip of INVENSENSE company.

Furthermore, the signal processing module comprises an X-axis signal processing circuit, a Y-axis signal processing circuit, a Z-axis signal processing circuit and an AD conversion circuit;

the X-axis differential amplification filter circuit comprises: the circuit comprises an amplification chip IC8, an IC9, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a seventeenth nonpolar capacitor C17 and an eighteenth nonpolar capacitor C18;

1 pin, 5 pins and 8 pins of the amplification chip IC8 are suspended; the pin 2 of the amplifying chip and one end of the third resistor R3 are connected with one end of the sixth resistor R6; a pin 3 of the amplifying chip and one end of a fourth resistor R4 are connected with one end of a fifth resistor R5; the other ends of the third resistor R3 and the fourth resistor R4 are connected with

pins

3 and 6 of the sensor chip IC 5; the pin 6 of the amplifying chip IC8 and the other end of the sixth resistor R6 are connected to one end of the seventh resistor R7; the other end of the seventh resistor R7, the eighth resistor R8, the ninth resistor R9 and the seventeenth nonpolar capacitor C17 are connected; 1 pin, 5 pins and 8 pins of the amplifying chip IC9 are suspended; a pin 2 of the amplifying chip IC9, the other end of the ninth resistor R9 and one end of the eighteenth nonpolar capacitor C18 are connected; the pin 6 of the amplifying chip IC9, the other end of the eighth resistor R8 and the other end of the eighteenth nonpolar capacitor C18 are connected with the pin 60 of the digital-analog conversion chip IC 13; the 7 pins of the amplifying chip IC8 and IC9 are connected with a +5V output voltage power supply; the other end of the fifth resistor R5, the amplifying chip IC8, the pin 4 of the amplifying chip IC9, the other end of the seventeenth nonpolar capacitor C17 and the other end of the tenth resistor R10 are grounded; the intermediate differential amplification chips IC8 and IC9 are full differential amplification chips OPA27 with ultra-low power consumption and low distortion of ADI company;

the Y-axis differential amplification filter circuit comprises: the circuit comprises an amplification chip IC10, an IC11, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16, a seventeenth resistor R17, an eighteenth resistor R18, a nineteenth nonpolar capacitor C19 and a twentieth nonpolar capacitor C20;

1 pin, 5 pins and 8 pins of the amplification chip IC10 are suspended; one end of the eleventh resistor R11 and the pin 2 of the amplifying chip is connected with one end of the fourteenth resistor R14; the pin 3 of the amplifying chip and one end of a twelfth resistor R12 are connected with one end of a thirteenth resistor R13; the other ends of the eleventh resistor R11 and the twelfth resistor R12 are connected with

pins

2 and 7 of the sensor chip IC 5; the pin 6 of the amplifying chip IC10 and the other end of the fourteenth resistor R14 are connected to one end of the fifteenth resistor R15; the other end of the fifteenth resistor R15, a sixteenth resistor R16, a seventeenth resistor R17 and a nineteenth nonpolar capacitor C19 are connected; 1 pin, 5 pins and 8 pins of the amplifying chip IC11 are suspended; the pin 2 of the amplifying chip IC11, the other end of the seventeenth resistor R17 and one end of the twentieth nonpolar capacitor C20 are connected; the pin 6 of the amplifying chip IC11, the other end of the sixteenth resistor R16 and the other end of the twentieth nonpolar capacitor C20 are connected with the pin 59 of the digital-to-analog conversion chip IC 13; the 7 pins of the amplifying chip IC10 and IC11 are connected with a +5V output voltage power supply; the other end of the thirteenth resistor R13, the amplifying chip IC10, the 4 th pin of the amplifying chip IC11, the other end of the nineteenth nonpolar capacitor C19 and the other end of the eighteenth resistor R18 are grounded; the intermediate differential amplification chips IC10 and IC11 are full differential amplification chips OPA27 with ultra-low power consumption and low distortion of ADI company;

the Z-axis differential amplification filter circuit comprises: the circuit comprises an amplification chip IC12, an IC13, a nineteenth resistor R19, a twentieth resistor R20, a twenty-first resistor R21, a twenty-second resistor R22, a twenty-third resistor R23, a twenty-fourth resistor R24, a twenty-fifth resistor R25, a twenty-sixth resistor R26, a twenty-first nonpolar capacitor C21 and a twenty-second nonpolar capacitor C22;

1 pin, 5 pins and 8 pins of the amplification chip IC12 are suspended; the 2 pin of the amplifying chip and one end of a nineteenth resistor R19 are connected with one end of a twenty-second resistor R22; the 3 pin of the amplifying chip and one end of a twentieth resistor R20 are connected with one end of a twenty-first resistor R21; the other ends of the nineteenth resistor R19 and the twentieth resistor R20 are connected with

pins

1 and 8 of the sensor chip IC 5; the pin 6 of the amplifying chip IC12 and the other end of the twenty-second twelve resistor R22 are connected with one end of a twenty-third resistor R23; the other end of the twenty-third resistor R23, the twenty-fourth resistor R24, the twenty-fifth resistor R25 and the twenty-first nonpolar capacitor C21 are connected; 1 pin, 5 pins and 8 pins of the amplifying chip IC13 are suspended; the pin 2 of the amplifying chip IC13, the other end of the fifteenth resistor R25 and one end of the twenty-second nonpolar capacitor C22 are connected; the pin 6 of the amplifying chip IC13, the other end of the twenty-fourth resistor R24 and the other end of the twenty-second nonpolar capacitor C22 are connected with the pin 64 of the digital-to-analog conversion chip IC 13; the 7 pins of the amplifying chip IC12 and IC13 are connected with a +5V output voltage power supply; the other end of the twenty-first resistor R21, the amplifying chip IC12, the 4-pin of the amplifying chip IC13, the other end of the twenty-first nonpolar capacitor C21 and the other end of the twenty-sixth resistor R26 are grounded; the intermediate differential amplification chips IC12 and IC13 are full differential amplification chips OPA27 with ultra-low power consumption and low distortion of ADI company;

the digital-to-analog conversion circuit includes: a digital-to-analog conversion chip IC13, a twenty-seventh resistor R27, a twenty-eighteenth resistor R28, a twenty-third nonpolar capacitor C23, a twenty-fourth nonpolar capacitor C24, a twenty-fifth nonpolar capacitor C25, a twenty-sixth nonpolar capacitor C26, a twenty-seventh nonpolar capacitor C27, a twenty-eighth nonpolar capacitor C28, a twenty-ninth nonpolar capacitor C29, a thirty-ninth nonpolar capacitor C30, a thirty-eleventh nonpolar capacitor C31, a thirty-second nonpolar capacitor C32, a seventh polar capacitor C7, and a socket P2;

pins

1, 2, 11, 12, 13, 14, 15, 16, 22, 23, 28 and 29 of the digital-to-analog conversion chip IC13 are suspended; a pin 4 of the digital-to-analog conversion chip IC13 and one end of a twenty-third nonpolar capacitor C23 are connected with a +5V output voltage power supply; a pin 6 of the digital-to-analog conversion chip IC13 and a twenty-fourth nonpolar capacitor C24 are connected with +4.096V output power supply voltage; a pin 21 of the digital-to-analog conversion chip IC13 is connected with one end of a twenty-seventh resistor R27; a pin 34 of the digital-to-analog conversion chip IC13 is connected with the anode of the seventh polarity capacitor Cp 7; a pin 35 of the digital-to-analog conversion chip IC13 and a twenty-fifth nonpolar capacitor C25 are connected with an IO interface and output power supply voltage of + 2.5V; a pin 43 of the digital-to-analog conversion chip IC13 and one end of a twenty-sixth nonpolar capacitor C26 are connected with +4.096V output power supply voltage; a pin 52 of the digital-to-analog conversion chip IC13 is connected with one end of a twenty-eight nonpolar capacitor C28; a pin 53 and a pin 60 of the digital-to-analog conversion chip IC13, one end of a twenty-ninth nonpolar capacitor C29 and a thirty-first nonpolar capacitor C31 are connected with +5V output power supply voltage; a pin 57 of the digital-to-analog conversion chip IC13 and one end of a thirtieth nonpolar capacitor are connected with an IO port +2.5V output power supply voltage; pin 61 of the digital-to-analog conversion chip IC13 is connected with a thirty-second nonpolar capacitor C32;

pins

3, 5, 7, 8, 9, 10, 31, 39, 40, 41, 42, 46, 51, 54, 62, the other end of the twenty-third non-polar capacitor C23, the other end of the sixteenth non-polar capacitor C26, the other end of the twenty-eighth non-polar capacitor C28, the other end of the twenty-ninth non-polar capacitor C29, the thirty-eleventh non-polar capacitor C31 and the thirty-second non-polar capacitor C32 of the digital-to-analog conversion chip IC13 are grounded;

pins

20, 33, 55, 56 and 58 of the digital-to-analog conversion chip IC13, the other end of the twenty-seventh resistor R27, the other end of the seventh polar capacitor Cp7, the other end of the twenty-fifth polar capacitor C25, the other end of the thirty-second polar capacitor and the digital ground are connected; pins 11, pins 12, pins 13, pins 14, pins 15, pins 16, pins 17, pins 18, pins 19, pins 24, pins 25, pins 26, pins 27 and pins 30 of the digital-to-analog conversion chip IC1316, pins 17, pins 18, pins 19, pins 24, pins 25, pins 26, pins 27 and pins 30 are connected with the socket P2; the digital-to-analog conversion chip IC13 selects an AD7768 chip with precise alternating current and direct current performances of ADI company;

there are several 0-value resistances between the digital ground and ground: a thirty-second resistor R32;

the 1 pin of the socket P2 is grounded; pin 2 is connected with +5V voltage input;

pins

3, 4, 5 and 6 of the socket P2 are connected with

pins

1, 2, 3 and 4 of the accelerometer sensor chip IC 6; the

pins

7, 8 and 9 of the socket P2 are connected with the

pins

12, 13 and 14 of the accelerometer sensor chip IC 6; the pin 10 of the socket P2 is connected with the pin 37 of the digital-to-analog conversion chip IC 10; the 10 pin of the socket P2 is suspended;

pins

11, 12, 13, 14, 15, 16, 17, 18, 19 and 20 of the socket P2, and

pins

16, 17, 18, 19, 24, 25, 26, 27 and 30 of the digital-to-analog conversion chip IC 10.

Compared with the prior art, the invention has the beneficial effects that: the filter of the circuit of the invention for the magnetic field signal uses a Butterworth filter in active filtering, and the filter is characterized in that the flatness of the frequency response curve in the pass band is very large, the fluctuation is very small, and the frequency response curve is reduced to zero in the stop band, therefore, when the boundary of the pass band meets the index requirement, the pass band is certainly provided with allowance; and secondly, compared with sensors such as AMR and GMR, the TMR sensor has the advantages of high magnetic field sensitivity, large magnetic resistance change rate, good linearity, good temperature stability, stable performance, no interlayer coupling effect and no need of an additional magnetic gathering ring structure and a set/reset coil structure, so that the number of peripheral circuits is reduced, and the power consumption of the overall circuit is reduced.

Drawings

FIG. 1 +5V buffer voltage power supply output circuit;

FIG. 2 +2.5V output voltage supply circuit;

FIG. 3 +3.3V output voltage supply circuit;

FIG. 4 IO interface +2.5V output voltage power supply circuit;

FIG. 5 TMR sensing circuit;

FIG. 6 an accelerometer sensing circuit;

FIG. 7 Gyroscope sense Circuit

FIG. 8 is an X-axis differential amplification circuit;

FIG. 9Y-axis differential amplifier circuit

FIG. 10 is a Z-axis differential amplifier circuit;

FIG. 11 digital to analog conversion circuit;

fig. 12 a patch port circuit.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1-12, the present invention provides a technical solution:

a low-noise measurement circuit of an inertia/geomagnetic combined navigation system based on a three-axis TMR sensor comprises a power module, a signal processing module and an information acquisition module, wherein the power module comprises a +2.5V output power circuit, a +3.3V output voltage power circuit and a +5V buffer voltage power circuit; the power supply circuit obtains +2.5V and +3.3V with smaller ripples through a +5V buffer power supply output circuit; wherein, the 2.5V output power circuit supplies power to the TMR sensor, the accelerometer and the IO interface power circuit; the +3.3V output voltage power supply circuit provides stable working voltage for the gyroscope;

pin 1 of the power chip IC1 is grounded; the positive electrode of the first polarity capacitor Cp1, the pin 3 of the power chip IC1 and one end of the patch port P1 are connected with the input of + 15V; pin 2 of the power chip IC2, and the anode of the second polarity capacitor Cp2 are connected with the output of +5V buffer voltage; the other end of the patch socket, the pin 1 of the power chip IC1, the other end of the first polarity capacitor Cp1 and the other end of the second polarity capacitor Cp2 are grounded; wherein, the power supply chip IC1 selects a low-voltage-stabilizing chip LM1117 with high voltage resistance and strong stability of NS company;

pins

1 and 3 of the power chip IC2 and the anode of the third polar capacitor Cp3 are connected with +5V buffer input voltage; the other end of the third polar capacitor Cp3 is grounded to pin 2 of the power chip IC 2; the pin 4 of the power chip IC2 is connected with one end of a first resistor R1 and one end of a second resistor R2, the other end of the second resistor R2 is grounded, and the other end of the first resistor R1 is connected with the pin 5 of the power chip IC2 and the anode of a fourth polarity capacitor Cp 4; the other end of the fourth polarity capacitor Cp4 is connected with a TMR power supply; the power supply chip IC2 selects ADI low quiescent current LDO linear regulator ADP 7118;

pins

1 and 3 of the power chip IC3 and one end of the first nonpolar capacitor are connected with a +5V output voltage power supply; the pin 4 of the power chip IC3 is connected with the second nonpolar capacitor C2 and the third nonpolar capacitor C3 to output voltage of + 3.3V; the pin 2 of the power chip IC3 is grounded to the other ends of the first nonpolar capacitor C1, the second nonpolar capacitor C2 and the third nonpolar capacitor C3; the power supply chip IC3 selects a reference voltage source chip RT9193 with high precision, low power consumption and low noise of RICHTEK company

pin 1 of the power chip IC4 is grounded; the positive electrode of the fifth polarity capacitor Cp5 and the 3-pin of the power chip IC4 are connected with the input of + 5V; a pin 2 of the power chip IC2 and the anode of the sixth polar capacitor Cp6 are connected with the power supply voltage +2.5V output of the IO port; the pin 1 of the power chip IC4, the other end of the fifth polarity capacitor Cp5 and the other end of the sixth polarity capacitor Cp6 are grounded; the power supply chip IC4 is a low-voltage-stabilizing chip LM1117 with high voltage resistance and high stability of NS company.

The information acquisition module comprises a triaxial tunneling magneto-resistance sensor circuit and an inertial sensor measuring circuit, wherein the triaxial tunneling magneto-resistance sensor circuit converts the magnetic field intensity variation into an analog voltage quantity to be output and then is connected to the signal processing circuit, and the inertial sensor measuring circuit directly outputs the measured information; the inertial sensor measuring circuit comprises an acceleration measuring circuit and a gyroscope measuring circuit;

a pin 5 of the triaxial tunneling magneto-resistive sensor chip IC5 is connected with a section of the fourth nonpolar capacitor C4 and a section of the fifth nonpolar capacitor C5 to output a +5V power supply voltage; the other ends of the fourth nonpolar capacitor C4 and the fifth nonpolar capacitor C5 and the 4-pin of the triaxial tunneling magneto-resistance sensor chip IC5 are grounded;

pins

3 and 6 of the three-axis tunneling magnetoresistive sensor chip IC5 are connected with X-axis magnetic field intensity output;

pins

1 and 8 of the three-axis tunneling magnetoresistive sensor chip IC5 are connected with the output of the magnetic field intensity of the Z axis; the tri-axial tunneling magneto-resistive sensor chip IC5 is a TMR2309 chip with good temperature stability selected by jiangsu multidimensional corporation.

The acceleration measurement circuit includes: the accelerometer sensor chip IC6, a sixth nonpolar capacitor C6, a seventh nonpolar capacitor C7, an eighth nonpolar capacitor C8, a ninth nonpolar capacitor C9, a tenth nonpolar capacitor C10, an eleventh nonpolar capacitor C11, a twelfth nonpolar capacitor C12, a thirteenth nonpolar capacitor C13 and a patch port P2;

pins 1, 2, 3 and 4 of the acceleration sensor IC6 are connected with pins 3, 4, 5 and 6 of the socket P2; one end of a pin 5 of the acceleration sensor IC6, one end of a tenth nonpolar capacitor C10 and one end of an eleventh nonpolar capacitor C11 are connected with an IO port voltage power supply +2.5V output; an 8 pin of the acceleration sensor IC6 is connected with one end of the twelfth nonpolar capacitor C12 and one end of the thirteenth nonpolar capacitor C13; the other ends of the tenth nonpolar capacitor C10, the eleventh nonpolar capacitor C11, the twelfth nonpolar capacitor C12 and the thirteenth nonpolar capacitor C13 are grounded at the pin 6 of the acceleration sensor IC 6; a pin 10 of the acceleration sensor IC6 is connected to one end of a sixth nonpolar capacitor C6 and one end of a seventh nonpolar capacitor C7; one end of the 11 pin of the acceleration sensor IC6, one end of the eighth nonpolar capacitor C8 and one end of the ninth nonpolar capacitor C9 are connected with an IO port voltage power supply +2.5V output; the other ends of a pin 9 of the acceleration sensor IC6, a sixth nonpolar capacitor C6, a seventh nonpolar capacitor C7, an eighth nonpolar capacitor C8 and a ninth nonpolar capacitor C9 are grounded; the pins 12, 13 and 14 of the acceleration sensor IC6 are connected with the pins 7, 8 and 9 of the socket P2; the acceleration sensor IC6 is implemented as a three-axis MEMS digital accelerometer ADXL355 from ADI.

The gyroscope measuring circuit comprises a sensing chip IC7, a fourteenth non-polar capacitor C14, a fifteenth non-polar capacitor C15, a sixteenth non-polar capacitor C16 and a third patch socket P3;

the

pins

6, 7, 9, 12, 23 and 24 of the sensing chip IC7 are connected with the

pins

5, 6, 7, 8, 3 and 4 of the third socket P3; one end of 8 pins and 13 pins of the sensing chip IC7 and one end of the fourteenth nonpolar capacitor C14 are connected with a +3.3V output voltage power supply; pin 10 of the sensing chip IC7 is connected to one end of the fifteenth nonpolar capacitor; pin 20 of the sensing chip IC7 is connected to one end of the sixteenth non-polar capacitor; pins 1, 11 and 18 of the sensing chip IC7 and the other ends of the fourteenth nonpolar capacitor C14, the fifteenth nonpolar capacitor C15 and the sixteenth nonpolar capacitor C16 are grounded; wherein the sensor chip IC7 is selected from the MPU6050 chip of INVENSENSE company.

The signal processing module comprises an X-axis signal processing circuit, a Y-axis signal processing circuit, a Z-axis signal processing circuit and an AD conversion circuit;

the X-axis differential amplification filter circuit includes: the circuit comprises an amplification chip IC8, an IC9, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a seventeenth nonpolar capacitor C17 and an eighteenth nonpolar capacitor C18;

1 pin, 5 pins and 8 pins of the amplifying chip IC8 are suspended; the pin 2 of the amplifying chip and one end of the third resistor R3 are connected with one end of the sixth resistor R6; a pin 3 of the amplifying chip and one end of a fourth resistor R4 are connected with one end of a fifth resistor R5; the other ends of the third resistor R3 and the fourth resistor R4 are connected with pins 3 and 6 of the sensor chip IC 5; the pin 6 of the amplifying chip IC8 and the other end of the sixth resistor R6 are connected to one end of the seventh resistor R7; the other end of the seventh resistor R7, the eighth resistor R8, the ninth resistor R9 and the seventeenth nonpolar capacitor C17 are connected; 1 pin, 5 pins and 8 pins of the amplifying chip IC9 are suspended; a pin 2 of the amplifying chip IC9, the other end of the ninth resistor R9 and one end of the eighteenth nonpolar capacitor C18 are connected; the pin 6 of the amplifying chip IC9, the other end of the eighth resistor R8 and the other end of the eighteenth nonpolar capacitor C18 are connected with the pin 60 of the digital-analog conversion chip IC 13; the 7 pins of the amplifying chip IC8 and IC9 are connected with a +5V output voltage power supply; the other end of the fifth resistor R5, the amplifying chip IC8, the pin 4 of the amplifying chip IC9, the other end of the seventeenth nonpolar capacitor C17 and the other end of the tenth resistor R10 are grounded; the intermediate differential amplification chips IC8 and IC9 are full differential amplification chips OPA27 with ultra-low power consumption and low distortion of ADI company;

1 pin, 5 pins and 8 pins of the amplifying chip IC10 are suspended; one end of the eleventh resistor R11 and the pin 2 of the amplifying chip is connected with one end of the fourteenth resistor R14; a pin 3 of the amplifying chip and one end of a twelfth resistor R12 are connected with one end of a thirteenth resistor R13; the other ends of the eleventh resistor R11 and the twelfth resistor R12 are connected with pins 2 and 7 of the sensor chip IC 5; the pin 6 of the amplifying chip IC10 and the other end of the fourteenth resistor R14 are connected to one end of the fifteenth resistor R15; the other end of the fifteenth resistor R15, a sixteenth resistor R16, a seventeenth resistor R17 and a nineteenth nonpolar capacitor C19 are connected; 1 pin, 5 pins and 8 pins of the amplifying chip IC11 are suspended; the pin 2 of the amplifying chip IC11, the other end of the seventeenth resistor R17 and one end of the twentieth nonpolar capacitor C20 are connected; the pin 6 of the amplifying chip IC11, the other end of the sixteenth resistor R16 and the other end of the twentieth nonpolar capacitor C20 are connected with the pin 59 of the digital-to-analog conversion chip IC 13; the 7 pins of the amplifying chip IC10 and IC11 are connected with a +5V output voltage power supply; the other end of the thirteenth resistor R13, the amplifying chip IC10, the 4 th pin of the amplifying chip IC11, the other end of the nineteenth nonpolar capacitor C19 and the other end of the eighteenth resistor R18 are grounded; the intermediate differential amplification chips IC10 and IC11 are full differential amplification chips OPA27 with ultra-low power consumption and low distortion of ADI company;

1 pin, 5 pins and 8 pins of the amplifying chip IC12 are suspended; the 2 pin of the amplifying chip and one end of a nineteenth resistor R19 are connected with one end of a twenty-second resistor R22; the 3 pin of the amplifying chip and one end of a twentieth resistor R20 are connected with one end of a twenty-first resistor R21; the other ends of the nineteenth resistor R19 and the twentieth resistor R20 are connected with pins 1 and 8 of the sensor chip IC 5; the pin 6 of the amplifying chip IC12 and the other end of the twenty-second resistor R22 are connected with one end of a twenty-third resistor R23; the other end of the twenty-third resistor R23, the twenty-fourth resistor R24, the twenty-fifth resistor R25 and the twenty-first nonpolar capacitor C21 are connected; 1 pin, 5 pins and 8 pins of the amplifying chip IC13 are suspended; the pin 2 of the amplifying chip IC13, the other end of the twenty-fifth resistor R25 and one end of the twenty-second nonpolar capacitor C22 are connected; the pin 6 of the amplifying chip IC13, the other end of the twenty-fourth resistor R24 and the other end of the twenty-second nonpolar capacitor C22 are connected with the pin 64 of the digital-to-analog conversion chip IC 13; the 7 pins of the amplifying chip IC12 and IC13 are connected with a +5V output voltage power supply; the other end of the twenty-first resistor R21, the amplifying chip IC12, the 4 feet of the amplifying chip IC13, the other end of the twenty-first nonpolar capacitor C21 and the other end of the twenty-sixth resistor R26 are grounded; the intermediate differential amplification chips IC12 and IC13 are full differential amplification chips OPA27 with ultra-low power consumption and low distortion of ADI company;

the digital-to-analog conversion circuit includes: a digital-to-analog conversion chip IC13, a twenty-seventh resistor R27, a twenty-eighth resistor R28, a twenty-third nonpolar capacitor C23, a twenty-fourth nonpolar capacitor C24, a twenty-fifth nonpolar capacitor C25, a twenty-sixth nonpolar capacitor C26, a twenty-seventh nonpolar capacitor C27, a twenty-eighth nonpolar capacitor C28, a twenty-ninth nonpolar capacitor C29, a thirty-ninth nonpolar capacitor C30, a thirty-eleventh nonpolar capacitor C31, a thirty-second nonpolar capacitor C32, a seventh polar capacitor C7, and a patch port P2;

pins 1, 2, 11, 12, 13, 14, 15, 16, 22, 23, 28 and 29 of the digital-to-analog conversion chip IC13 are suspended; a pin 4 of the digital-to-analog conversion chip IC13 and one end of a twenty-third nonpolar capacitor C23 are connected with a +5V output voltage power supply; a pin 6 of the digital-to-analog conversion chip IC13 and a twenty-fourth nonpolar capacitor C24 are connected with +4.096V output power supply voltage; a pin 21 of the digital-to-analog conversion chip IC13 is connected with one end of a twenty-seventh resistor R27; a pin 34 of the digital-to-analog conversion chip IC13 is connected with the anode of the seventh polarity capacitor Cp 7; a pin 35 of the digital-to-analog conversion chip IC13 and a twenty-fifth nonpolar capacitor C25 are connected with an IO interface and output power supply voltage of + 2.5V; a pin 43 of the digital-to-analog conversion chip IC13 and one end of a twenty-sixth nonpolar capacitor C26 are connected with +4.096V output power supply voltage; a pin 52 of the digital-to-analog conversion chip IC13 is connected with one end of a twenty-eight nonpolar capacitor C28; a pin 53 and a pin 60 of the digital-to-analog conversion chip IC13, one end of a twenty-ninth nonpolar capacitor C29 and a thirty-first nonpolar capacitor C31 are connected with +5V output power supply voltage; a pin 57 of the digital-to-analog conversion chip IC13 and one end of a thirtieth nonpolar capacitor are connected with an IO port +2.5V output power supply voltage; pin 61 of the digital-to-analog conversion chip IC13 is connected with a thirty-second nonpolar capacitor C32; pins 3, 5, 7, 8, 9, 10, 31, 39, 40, 41, 42, 46, 51, 54, 62, the other end of the twenty-third non-polar capacitor C23, the other end of the twenty-sixth non-polar capacitor C26, the other end of the twenty-eighth non-polar capacitor C28, the other end of the twenty-ninth non-polar capacitor C29, the thirty-eleventh non-polar capacitor C31 and the thirty-second non-polar capacitor C32 of the digital-to-analog conversion chip IC13 are grounded; pins 20, 33, 55, 56 and 58 of the digital-to-analog conversion chip IC13, the other end of the twenty-seventh resistor R27, the other end of the seventh polar capacitor Cp7, the other end of the twenty-fifth polar capacitor C25, the other end of the thirty-second polar capacitor and the digital ground are connected; pins 11, pins 12, pins 13, pins 14, pins 15, pins 16, pins 17, pins 18, pins 19, pins 24, pins 25, pins 26, pins 27 and pins 30 of the digital-to-analog conversion chip IC1316, pins 17, pins 18, pins 19, pins 24, pins 25, pins 26, pins 27 and pins 30 are connected with the socket P2; the digital-to-analog conversion chip IC13 selects an AD7768 chip with precise alternating current and direct current performances of ADI company;

there are several 0-value resistances between digital ground and ground: a thirty-second resistor R32;

pin 1 of socket P2 is grounded; pin 2 is connected with +5V voltage input; pins 3, 4, 5 and 6 of the socket P2 are connected with

pins

1, 2, 3 and 4 of the accelerometer sensor chip IC 6; the

pins

7, 8 and 9 of the socket P2 are connected with the

pins

12, 13 and 14 of the accelerometer sensor chip IC 6; the 10 pins of the socket P2 are connected with the 37 pins of the digital-to-analog conversion chip IC 10; the 10 pin of the socket P2 is suspended; pins 11, 12, 13, 14, 15, 16, 17, 18, 19 and 20 of the socket P2, and pins 16, 17, 18, 19, 24, 25, 26, 27 and 30 of the digital-to-analog conversion chip IC 10.

Those not described in detail in this specification are within the skill of the art.

Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that various changes, modifications, equivalents, improvements and the like can be made therein without departing from the spirit and scope of the invention.

Claims

1. A low-noise measurement circuit of an inertia/geomagnetic combined navigation system based on a three-axis TMR sensor comprises a power supply module, a signal processing module and an information acquisition module, and is characterized in that the power supply module comprises a +2.5V output power supply circuit, a +3.3V output voltage power supply circuit and a +5V buffer voltage power supply circuit; the power supply circuit obtains +2.5V and +3.3V with smaller ripples through a +5V buffer power supply output circuit; wherein, the 2.5V output power circuit supplies power to the TMR sensor, the accelerometer and the IO interface power circuit; the +3.3V output voltage power supply circuit provides stable working voltage for the gyroscope;

the pin 1 and the pin 3 of the power chip IC2 and the anode of the third polar capacitor Cp3 are connected with +5V buffer input voltage; the other end of the third polar capacitor Cp3 is grounded to pin 2 of the power chip IC 2; the pin 4 of the power chip IC2 is connected with one end of a first resistor R1 and one end of a second resistor R2, the other end of the second resistor R2 is grounded, and the other end of the first resistor R1 is connected with the pin 5 of the power chip IC2 and the anode of a fourth polarity capacitor Cp 4; the other end of the fourth polarity capacitor Cp4 is connected with a TMR power supply; the power supply chip IC2 selects ADI low quiescent current LDO linear regulator ADP 7118;

the 1 pin of the power chip IC4 is grounded; the positive electrode of the fifth polarity capacitor Cp5 and the 3-pin of the power chip IC4 are connected with the input of + 5V; a pin 2 of the power chip IC2 and the anode of the sixth polar capacitor Cp6 are connected with the power voltage +2.5V output of the IO port; the pin 1 of the power chip IC4, the other end of the fifth polarity capacitor Cp5 and the other end of the sixth polarity capacitor Cp6 are grounded; the power supply chip IC4 is a low-voltage-stabilizing chip LM1117 with high voltage resistance and high stability of NS company.

2. A low-noise measurement circuit of an inertia/geomagnetic combined navigation system based on a three-axis TMR sensor is characterized in that an information acquisition module comprises a three-axis tunneling magnetic resistance sensor circuit and an inertial sensor measurement circuit, wherein the three-axis tunneling magnetic resistance sensor circuit converts magnetic field intensity variation into analog voltage to be output and then is connected to a signal processing circuit, and the inertial sensor measurement circuit directly outputs the measured information; the inertial sensor measuring circuit comprises an acceleration measuring circuit and a gyroscope measuring circuit;

a pin 5 of the triaxial tunneling magneto-resistive sensor chip IC5 is connected with a section of a fourth nonpolar capacitor C4 and a fifth nonpolar capacitor C5 to output a +5V power supply voltage; the other ends of the fourth nonpolar capacitor C4 and the fifth nonpolar capacitor C5 and the 4-pin of the triaxial tunneling magneto-resistance sensor chip IC5 are grounded; pins 3 and 6 of the three-axis tunneling magnetoresistive sensor chip IC5 are connected with X-axis magnetic field intensity output; pins 2 and 7 of the three-axis tunneling magnetoresistive sensor chip IC5 are connected with Y-axis magnetic field intensity output; pins 1 and 8 of the three-axis tunneling magnetoresistive sensor chip IC5 are connected with the output of the magnetic field intensity of the Z axis; the tri-axial tunneling magneto-resistance sensor chip IC5 is a TMR2309 chip which is good in temperature stability and is made by Jiangsu multidimensional corporation.

3. An inertia/geomagnetic combined navigation system low-noise measurement circuit based on a three-axis TMR sensor, wherein the acceleration measurement circuit comprises: the accelerometer sensor chip IC6, a sixth nonpolar capacitor C6, a seventh nonpolar capacitor C7, an eighth nonpolar capacitor C8, a ninth nonpolar capacitor C9, a tenth nonpolar capacitor C10, an eleventh nonpolar capacitor C11, a twelfth nonpolar capacitor C12, a thirteenth nonpolar capacitor C13 and a patch port P2;

the 1 pin, the 2 pin, the 3 pin and the 4 pin of the acceleration sensor IC6 are connected with the 3 pin, the 4 pin, the 5 pin and the 6 pin of the socket P2; one end of a pin 5 of the acceleration sensor IC6, one end of a tenth nonpolar capacitor C10 and one end of an eleventh nonpolar capacitor C11 are connected with an IO port voltage power supply +2.5V output; an 8 pin of the acceleration sensor IC6 is connected with one end of the twelfth nonpolar capacitor C12 and one end of the thirteenth nonpolar capacitor C13; the other ends of the tenth nonpolar capacitor C10, the eleventh nonpolar capacitor C11, the twelfth nonpolar capacitor C12 and the thirteenth nonpolar capacitor C13 are grounded at the pin 6 of the acceleration sensor IC 6; the pin 10 of the acceleration sensor IC6 is connected to one end of a sixth nonpolar capacitor C6 and one end of a seventh nonpolar capacitor C7; one end of the 11 pin of the acceleration sensor IC6, one end of the eighth nonpolar capacitor C8 and one end of the ninth nonpolar capacitor C9 are connected with an IO port voltage power supply +2.5V output; the other ends of a pin 9 of the acceleration sensor IC6, a sixth nonpolar capacitor C6, a seventh nonpolar capacitor C7, an eighth nonpolar capacitor C8 and a ninth nonpolar capacitor C9 are grounded; the pins 12, 13 and 14 of the acceleration sensor IC6 are connected with the pins 7, 8 and 9 of the socket P2; the acceleration sensor IC6 is implemented as a three-axis MEMS digital accelerometer ADXL355 from ADI.

4. The inertia/geomagnetic combined navigation system low-noise measurement circuit based on the three-axis TMR sensor is characterized in that the gyroscope measurement circuit comprises a sensing chip IC7, a fourteenth nonpolar capacitor C14, a fifteenth nonpolar capacitor C15, a sixteenth nonpolar capacitor C16 and a third patch socket P3;

the pins 2, 3, 4, 5, 14, 15, 16, 17, 21 and 22 of the sensing chip IC7 are suspended; the pins 6, 7, 9, 12, 23 and 24 of the sensing chip IC7 are connected with the pins 5, 6, 7, 8, 3 and 4 of the third socket P3; one end of 8 pins and 13 pins of the sensing chip IC7 and one end of the fourteenth nonpolar capacitor C14 are connected with a +3.3V output voltage power supply; pin 10 of the sensing chip IC7 is connected to one end of the fifteenth nonpolar capacitor; pin 20 of the sensing chip IC7 is connected to one end of the sixteenth non-polar capacitor; pins 1, 11 and 18 of the sensing chip IC7 and the other ends of the fourteenth nonpolar capacitor C14, the fifteenth nonpolar capacitor C15 and the sixteenth nonpolar capacitor C16 are grounded; wherein the sensor chip IC7 is selected from the MPU6050 chip of INVENSENSE company.

5. The inertia/geomagnetic combined navigation system low-noise measurement circuit based on the three-axis TMR sensor is characterized in that the signal processing module comprises an X-axis signal processing circuit, a Y-axis signal processing circuit, a Z-axis signal processing circuit and an AD conversion circuit;

1 pin, 5 pins and 8 pins of the amplification chip IC8 are suspended; the pin 2 of the amplifying chip and one end of the third resistor R3 are connected with one end of the sixth resistor R6; a pin 3 of the amplifying chip and one end of a fourth resistor R4 are connected with one end of a fifth resistor R5; the other ends of the third resistor R3 and the fourth resistor R4 are connected with pins 3 and 6 of the sensor chip IC 5; the pin 6 of the amplifying chip IC8 and the other end of the sixth resistor R6 are connected to one end of the seventh resistor R7; the other end of the seventh resistor R7, the eighth resistor R8, the ninth resistor R9 and the seventeenth nonpolar capacitor C17 are connected; 1 pin, 5 pins and 8 pins of the amplifying chip IC9 are suspended; a pin 2 of the amplifying chip IC9, the other end of the ninth resistor R9 and one end of the eighteenth nonpolar capacitor C18 are connected; the pin 6 of the amplifying chip IC9, the other end of the eighth resistor R8 and the other end of the eighteenth nonpolar capacitor C18 are connected with the pin 60 of the digital-to-analog conversion chip IC 13; the 7 pins of the amplifying chip IC8 and IC9 are connected with a +5V output voltage power supply; the other end of the fifth resistor R5, the amplifying chip IC8, the pin 4 of the amplifying chip IC9, the other end of the seventeenth nonpolar capacitor C17 and the other end of the tenth resistor R10 are grounded; the intermediate differential amplification chips IC8 and IC9 are full differential amplification chips OPA27 with ultra-low power consumption and low distortion of ADI company;

1 pin, 5 pins and 8 pins of the amplification chip IC10 are suspended; one end of the eleventh resistor R11 and the pin 2 of the amplifying chip is connected with one end of the fourteenth resistor R14; the pin 3 of the amplifying chip and one end of a twelfth resistor R12 are connected with one end of a thirteenth resistor R13; the other ends of the eleventh resistor R11 and the twelfth resistor R12 are connected with pins 2 and 7 of the sensor chip IC 5; the pin 6 of the amplifying chip IC10 and the other end of the fourteenth resistor R14 are connected to one end of the fifteenth resistor R15; the other end of the fifteenth resistor R15, a sixteenth resistor R16, a seventeenth resistor R17 and a nineteenth nonpolar capacitor C19 are connected; 1 pin, 5 pins and 8 pins of the amplifying chip IC11 are suspended; the pin 2 of the amplifying chip IC11, the other end of the seventeenth resistor R17 and one end of the twentieth nonpolar capacitor C20 are connected; the pin 6 of the amplifying chip IC11, the other end of the sixteenth resistor R16 and the other end of the twentieth nonpolar capacitor C20 are connected with the pin 59 of the digital-to-analog conversion chip IC 13; the 7 pins of the amplifying chip IC10 and IC11 are connected with a +5V output voltage power supply; the other end of the thirteenth resistor R13, the amplifying chip IC10, the 4 th pin of the amplifying chip IC11, the other end of the nineteenth nonpolar capacitor C19 and the other end of the eighteenth resistor R18 are grounded; the intermediate differential amplification chips IC10 and IC11 are full differential amplification chips OPA27 with ultra-low power consumption and low distortion of ADI company;

1 pin, 5 pins and 8 pins of the amplification chip IC12 are suspended; the 2 pin of the amplifying chip and one end of a nineteenth resistor R19 are connected with one end of a twenty-second resistor R22; the 3 pin of the amplifying chip and one end of a twentieth resistor R20 are connected with one end of a twenty-first resistor R21; the other ends of the nineteenth resistor R19 and the twentieth resistor R20 are connected with pins 1 and 8 of the sensor chip IC 5; the pin 6 of the amplifying chip IC12 and the other end of the twenty-second resistor R22 are connected with one end of a twenty-third resistor R23; the other end of the twenty-third resistor R23, the twenty-fourth resistor R24, the twenty-fifth resistor R25 and the twenty-first nonpolar capacitor C21 are connected; 1 pin, 5 pins and 8 pins of the amplifying chip IC13 are suspended; a pin 2 of the amplifying chip IC13, the other end of the twenty-fifth resistor R25 and one end of the twenty-second nonpolar capacitor C22 are connected; the pin 6 of the amplifying chip IC13, the other end of the twenty-fourth resistor R24 and the other end of the twenty-second nonpolar capacitor C22 are connected with the pin 64 of the digital-to-analog conversion chip IC 13; the 7 pins of the amplifying chip IC12 and IC13 are connected with a +5V output voltage power supply; the other end of the twenty-first resistor R21, the amplifying chip IC12, the 4-pin of the amplifying chip IC13, the other end of the twenty-first nonpolar capacitor C21 and the other end of the twenty-sixth resistor R26 are grounded; the intermediate differential amplification chips IC12 and IC13 are full differential amplification chips OPA27 with ultra-low power consumption and low distortion of ADI company;

pins 1, 2, 11, 12, 13, 14, 15, 16, 22, 23, 28 and 29 of the digital-to-analog conversion chip IC13 are suspended; a pin 4 of the digital-to-analog conversion chip IC13 and one end of a twenty-third nonpolar capacitor C23 are connected with a +5V output voltage power supply; a pin 6 of the digital-to-analog conversion chip IC13 and a twenty-fourth nonpolar capacitor C24 are connected with +4.096V output power supply voltage; a pin 21 of the digital-to-analog conversion chip IC13 is connected with one end of a twenty-seventh resistor R27; a pin 34 of the digital-to-analog conversion chip IC13 is connected with the anode of the seventh polarity capacitor Cp 7; a pin 35 of the digital-to-analog conversion chip IC13 and a twenty-fifth nonpolar capacitor C25 are connected with an IO interface and output power supply voltage of + 2.5V; a pin 43 of the digital-to-analog conversion chip IC13 and one end of a twenty-sixth nonpolar capacitor C26 are connected with +4.096V output power supply voltage; a pin 52 of the digital-to-analog conversion chip IC13 is connected with one end of a twenty-eighth nonpolar capacitor C28; a pin 53 and a pin 60 of the digital-to-analog conversion chip IC13, one end of a twenty-ninth nonpolar capacitor C29 and a thirty-first nonpolar capacitor C31 are connected with +5V output power supply voltage; a pin 57 of the digital-to-analog conversion chip IC13 and one end of a thirtieth nonpolar capacitor are connected with an IO port +2.5V output power supply voltage; pin 61 of the digital-to-analog conversion chip IC13 is connected with a thirty-second nonpolar capacitor C32; pins 3, 5, 7, 8, 9, 10, 31, 39, 40, 41, 42, 46, 51, 54, 62, the other end of the twenty-third non-polar capacitor C23, the other end of the twenty-sixth non-polar capacitor C26, the other end of the twenty-eighth non-polar capacitor C28, the other end of the twenty-ninth non-polar capacitor C29, the thirty-eleventh non-polar capacitor C31 and the thirty-second non-polar capacitor C32 of the digital-to-analog conversion chip IC13 are grounded; pins 20, 33, 55, 56 and 58 of the digital-to-analog conversion chip IC13, the other end of a twenty-seventh resistor R27, the other end of a seventh polar capacitor Cp7, the other end of a twenty-fifth polar capacitor C25 and the other end of a thirty-second polar capacitor are connected with digital ground; pins 11, pins 12, pins 13, pins 14, pins 15, pins 16, pins 17, pins 18, pins 19, pins 24, pins 25, pins 26, pins 27 and pins 30 of the digital-to-analog conversion chip IC1316, pins 17, pins 18, pins 19, pins 24, pins 25, pins 26, pins 27 and pins 30 are connected with the socket P2; the digital-to-analog conversion chip IC13 selects an AD7768 chip with precise alternating current and direct current performances of ADI company;

the 1 pin of the socket P2 is grounded; pin 2 is connected with +5V voltage input; pins 3, 4, 5 and 6 of the socket P2 are connected with pins 1, 2, 3 and 4 of the accelerometer sensor chip IC 6; the pins 7, 8 and 9 of the socket P2 are connected with the pins 12, 13 and 14 of the accelerometer sensor chip IC 6; the 10 pins of the socket P2 are connected with the 37 pins of the digital-to-analog conversion chip IC 10; the 10 pin of the socket P2 is suspended; pins 11, 12, 13, 14, 15, 16, 17, 18, 19 and 20 of the socket P2, and pins 16, 17, 18, 19, 24, 25, 26, 27 and 30 of the digital-to-analog conversion chip IC 10.