CN111679097B - High-precision accelerometer temperature compensation method - Google Patents
High-precision accelerometer temperature compensation method Download PDFInfo
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- CN111679097B CN111679097B CN202010419874.6A CN202010419874A CN111679097B CN 111679097 B CN111679097 B CN 111679097B CN 202010419874 A CN202010419874 A CN 202010419874A CN 111679097 B CN111679097 B CN 111679097B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
- G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
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- G—PHYSICS
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- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
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Abstract
The invention discloses a high-precision accelerometer temperature compensation method, and belongs to the field of inertial measurement. The quartz flexible accelerometer consists of a gauge head component and a servo circuit component. The change of the environmental temperature can change the physical parameters of various materials in the quartz flexible accelerometer, thereby influencing the output of the accelerometer. The invention provides a single-surface-level two-way variable temperature modeling method for a marble tool, which eliminates the influence of the deformation of a strapdown inertial navigation combination body and a test tool on the precision of an accelerometer in the traditional temperature modeling process and realizes the precision of the zero-offset stability 3 sigma of the accelerometer of less than or equal to 0.05mg under the full-temperature condition.
Description
Technical Field
The invention relates to an accelerometer temperature compensation method for high-precision and small-volume strapdown inertial navigation for navigation and guidance, and belongs to the field of inertial measurement.
Background
The quartz flexible accelerometer is one of core sensitive elements of a strapdown inertial navigation system, and the precision of the quartz flexible accelerometer directly influences the attitude, the speed and the positioning precision of the navigation system. Factors such as ambient temperature, vibration, magnetic field, and air pressure all affect the accuracy of the accelerometer, with the effect of ambient temperature being particularly important. Therefore, the influence of the ambient temperature needs to be considered when designing the inertial navigation system. At present, the measure for improving the influence of temperature on the accelerometer in China is mainly temperature control or temperature compensation. The temperature control method is to add a temperature control system to the accelerometer to enable the accelerometer to work in a relatively constant temperature environment to resist the influence caused by the change of the external temperature, and has the defects of long temperature stabilization time and large power consumption, so that the requirements of a quick-start and low-power consumption strapdown navigation system cannot be met. The temperature compensation is a software compensation method, firstly a model of accelerometer output changing with temperature is established through a certain test method, then the accelerometer output is corrected by software according to the measured accelerometer temperature, thereby improving the measurement accuracy of the accelerometer.
To realize accurate temperature compensation, an accurate accelerometer temperature error model must be established, and the influence of temperature on the output of an accelerometer component in an inertial navigation system is mainly expressed in two aspects: on one hand, when the system works normally, the scale factor of the accelerometer and zero offset change due to the internal temperature change of the system, so that the measurement of the accelerometer component is misaligned; on the other hand, under the influence of temperature, structural deformation is generated on a structural body, test equipment and the like, so that the sensitive axis of the accelerometer deviates, the installation error is further caused to change, and the measurement precision of the accelerometer assembly is influenced. For the inertial navigation system with medium and low precision, the effect of temperature compensation on zero offset and scale factors is the best, and the precision can also meet the requirement, but for the inertial navigation system with high precision, if the test equipment generates 2 arc seconds of deformation, the method is equivalent to that 1 x 10 is introduced into the accelerometer-5g, the deformation of the structure body and the test fixture caused by the deformation cannot be ignored, and the deformation cannot be quantitatively measured in practice, so that a high-precision temperature compensation method needs to be designed to eliminate the error caused by the deformation of the installation.
Disclosure of Invention
The technical problem of the invention is solved: the defects in the prior art are overcome, the high-precision accelerometer temperature compensation method is provided, and the influence of deformation of a combined body and a test tool on the precision of an accelerometer in high-precision strapdown inertial navigation in the temperature modeling process is eliminated.
The technical solution of the invention is as follows:
a high-precision accelerometer temperature compensation method comprises the following steps:
(1) mounting three accelerometers in the strapdown inertial navigation on a marble tool;
(2) placing the marble tool in a temperature control test box, and enabling the sensitive elements of the accelerometers to point to the sky after the marble tool is placed;
(3) the accelerometer is connected with an external strapdown inertial navigation data acquisition system through a cable, a temperature control test box door is closed, a temperature control program of the temperature control test box is set, the temperature of the temperature control test box is kept at the low temperature of 40 ℃ below zero for 3 hours, then the temperature of the temperature control test box is increased at the rising rate of 0.25 ℃/min, and the temperature is kept for 0.5 hour when the temperature reaches 70 ℃;
(4) after the temperature of the temperature test box is kept at the low temperature of 40 ℃ below zero for 3 hours, a power supply of an external strapdown inertial navigation data acquisition system is turned on, the output of the accelerometer is acquired in real time along with the temperature rise of the temperature test box, and the power supply of the external strapdown inertial navigation data acquisition system is turned off until the temperature is kept at the high temperature of 70 ℃ for 0.5 hour;
(5) setting the temperature of the temperature control test box to be 25 ℃ at normal temperature, opening the door of the temperature control test box after the temperature control test box reaches 25 ℃ at normal temperature, and changing the direction of the marble tool in the temperature control test box to enable the sensitive elements of the accelerometers to point to the ground;
(6) closing the door of the temperature control test box, setting a temperature control program of the temperature control test box, keeping the temperature of the temperature control test box at the low temperature of 40 ℃ below zero for 3 hours, then heating the temperature control test box at the rising rate of 0.25 ℃/min, and stabilizing for 0.5 hour when the temperature reaches 70 ℃;
(7) after the temperature of the temperature control test box is kept at the temperature of minus 40 ℃ for 3 hours, a power supply of an external strapdown inertial navigation data acquisition system is turned on, the output of the accelerometer is acquired in real time along with the temperature rise of the temperature control test box, and the power supply of the external strapdown inertial navigation data acquisition system is turned off until the temperature is kept at the high temperature of 70 ℃ for 0.5 hour;
(8) establishing a zero-position temperature model and a scale factor temperature error model of the accelerometer, fitting to obtain a zero-position curve of the accelerometer according to the outputs of the two groups of accelerometers and the zero-position temperature error model of the accelerometer, which are acquired by an external strapdown inertial navigation data acquisition system, and fitting to obtain a scale factor curve of the accelerometer according to the outputs of the two groups of accelerometers and the scale factor temperature error model of the accelerometer, which are acquired by the external strapdown inertial navigation data acquisition system;
(9) and (4) carrying out temperature compensation on the output of the accelerometer by using the zero position curve and the scale factor curve of the accelerometer to obtain high-precision accelerometer output.
The marble frock matrix structure is the hexahedron, and the upper surface processing has accelerometer mounting groove, and processing has the mounting hole on mounting groove's basal body surface for the fixed accelerometer of installation.
The planeness of the marble tooling is less than or equal to 2 arc seconds.
The flatness of the mounting hole is less than or equal to 2 arc seconds.
In the step (1), a plurality of accelerometers for strapdown inertial navigation can be mounted on the marble tool.
The zero temperature error model for the accelerometer is as follows:
wherein A is0TxFor zero position of accelerometer in X direction, A0TyZero position of accelerometer in Y direction, A0TzIs the zero position of the accelerometer in the Z direction,
the output of the accelerometer in the X direction towards the sky, the output of the accelerometer in the Y direction towards the sky and the output of the accelerometer in the Z direction towards the sky are respectively;
respectively, the output of the accelerometer in the X direction facing the ground, the output of the accelerometer in the Y direction facing the ground and the output of the accelerometer in the Z direction facing the ground; kaxT、KayT、KazTThe scale factors of the accelerometer in the X direction, the scale factor of the accelerometer in the Y direction and the scale factor of the accelerometer in the Z direction are respectively;
KIFPxis the X-direction positive scale factor of the IF conversion circuit; kIFNxIs the negative scale factor of the X direction of the IF conversion circuit; kIFPyIs the Y-direction positive scale factor of the IF conversion circuit; kIFNyIs the Y-direction negative scale factor of the IF conversion circuit; kIFPzIs the Z-direction positive scale factor of the IF conversion circuit; kIFNzIs the Z-direction negative scaling factor of the IF conversion circuit.
The scale factor temperature error model for the accelerometer is as follows:
the accelerometer in the step (1) is additionally provided with an insulating terminal on the basis of 10 insulating glass terminals of a traditional accelerometer, meanwhile, the head of the accelerometer in the step (1) is packaged with a temperature sensor, three output pins of the temperature sensor are connected with three insulating glass terminals, and the three insulating glass terminals comprise the additionally arranged insulating glass terminals and two of the original 10 insulating glass terminals.
The accelerometer channel in the strapdown inertial navigation adopts a high-precision IF conversion circuit, and the asymmetry of positive and negative scale factors is less than or equal to 30 ppm.
The invention has the following advantages:
(1) the invention establishes a zero position and scale factor temperature error model of the accelerometer, and simultaneously adopts a variable temperature mode to acquire the outputs of the accelerometer when the accelerometer faces the sky and the ground, thereby obtaining a fitting curve of the zero position and the scale factor and realizing high-precision compensation of the accelerometer.
(2) The temperature sensor for measuring the temperature signal of the accelerometer is arranged near the inner gauge head of the accelerometer and can reflect the inner temperature of the accelerometer.
(3) According to the invention, three accelerometers in the strapdown inertial navigation are installed on a marble tool special for the accelerometer, the hardness of marble is high, the flatness is less than or equal to 2 arc seconds, the marble has almost no deformation under the condition of temperature change, and the influence of the deformation of a test tool on the precision of the accelerometer in the temperature modeling process is eliminated.
(4) The invention adopts a temperature changing mode of 0.25 ℃/min within the range of-40 ℃ to +70 ℃, compared with a constant temperature mode of a fixed temperature point, the acceleration can cover the whole working temperature range of-40 ℃ to +70 ℃, and simultaneously, the time of temperature modeling is shortened, thereby improving the efficiency.
(5) When the analog quantity and the digital quantity output by the accelerometer are output, the high-precision IF conversion circuit with the asymmetry of the positive and negative scale factors of less than or equal to 30ppm is selected, and when the zero position of the accelerometer is calculated, errors caused by the asymmetry of the positive and negative scale factors of the IF conversion circuit can be ignored, so that the method is more suitable for engineering application.
Drawings
Fig. 1 is a schematic view of a marble tooling of the present invention;
FIG. 2 is an external view of an accelerometer of the present invention;
FIG. 3 is a schematic diagram of a temperature modeling test connection according to the present invention;
FIG. 4 is a temperature-modeled temperature-variation curve of the present invention;
FIG. 5 is a data comparison graph of accelerometer zero output before and after high accuracy temperature modeling of the accelerometer;
FIG. 6 is a comparison of output data from accelerometer scaling factors before and after high accuracy temperature modeling of the accelerometer.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
In strapdown inertial navigation, the output characteristics of the three accelerometers can be expressed as equation (1):
in the formula:
Ax、Ay、Azx, Y, Z the output (LSB) of the three directional accelerometer;
A0x、A0y、A0zx, Y, Z zero position (LSB) of three directional accelerometers;
KAx、KAy、KAzx, Y, Z scale factors of three directional accelerometers (LSB/(m/s)2))；
ax、ay、azAcceleration (m/s) in three axes of an orthogonal coordinate system to be measured2) Inputting the local gravity acceleration for the standard in the calibration process;
FAij(i x, y, z, j x, y, z) -an accelerometer mounting error coefficient, i representing the input axis and j representing the affected axis.
In addition, when an accelerometer temperature modeling method is designed, installation errors which cannot be measured quantitatively are reduced as much as possible, and high-precision accelerometer output can be obtained by substituting temperature curves of the zero position and the scale factor of the accelerometer into the formula (1).
The modeling design of the accelerometer zero position and scale factor temperature error model is as follows:
in strapdown inertial navigation, the tri-orthogonal accelerometer is defined as the X, Y, Z axis, with the Y axis pointing upward, the X axis output being equation (2) (the Z axis input is small, with negligible effect on the X axis mounting error).
The X-axis output when the Y-axis is towards ground can be represented by equation (3).
Wherein the content of the first and second substances,
the output of the X-axis accelerometer when the Y-axis is towards the sky;
A0T: zero position of the X accelerometer;
FUyx: when the Y axis faces the sky, the installation error of the X axis accelerometer by the Y axis;
FDyx: when the Y axis faces the ground, the installation error of the Y axis to the X axis accelerometer;
FyxT: temperature-dependent variation term of installation error of Y axis to X axis
The T subscript is the amount of change with temperature, others can be considered fixed terms.
The sum of (2) + (3) gives the formula (4).
In the formula (4), only the trend term of the zero offset along with the temperature can obtain a temperature error model of the zero offset of the X-axis accelerometer.
Similarly, when the Z axis is towards the sky and towards the earth, the formula (5) can be obtained.
Wherein the content of the first and second substances,
when the Z axis is facing the sky, the X axisAn output of the accelerometer;
A0T: zero position of the X accelerometer;
FUzx: when the Z axis faces the sky, the installation error of the Z axis to the X axis accelerometer;
FDzx: when the Z axis faces the ground, the installation error of the Z axis to the X axis accelerometer;
the X-axis output when the X-axis is toward the sky can be represented by equation (6) (the other axis inputs are small, which has negligible effect on the X-axis mounting error).
The X-axis output when the X-axis is towards ground can be represented by equation (7).
Formula (8) is obtained from formula (6) + formula (7).
Wherein:
the output of the X-axis accelerometer when the X-axis is towards the sky;
A0T: zero position of the X accelerometer;
KIFPx: an X-direction forward scale factor of the IF conversion circuit;
KIFNx: an X-direction negative scale factor of the IF conversion circuit;
KaxT: a scale factor temperature error term for the X-axis;
in the formula (8), (K)IFPx-KIFNx) About 0.5%, KaxTAt most about 0.5%, so that g × (K) in formula (7)IFPx-KIFNx)×KaxTIt can be understood as a small quantity, so that a temperature model of the zero offset of the X-accelerometer can be obtained.
The formula (9) is obtained from the formula (6) to the formula (7).
In the equation (9), only the trend term of the scale factor with the temperature is obtained, and a temperature error model of the scale factor can be obtained.
The zero position of the X-axis accelerometer can be obtained by the formulas (4), (5) and (8), and as can be seen from the formulas (4) and (5), the influence of the Y-axis up-and-down direction and the Z-axis up-and-down direction on the zero position of the X-axis accelerometer is mainly shown in the influence of installation errors, and in the formula (6), the influence of the X-axis up-and-down direction on the X-axis plus-meter zero position is mainly the influence of asymmetry of positive and negative scale factors.
When the temperature modeling is carried out on the accelerometer in the strapdown inertial navigation, the accelerometer with temperature output is installed on a special marble tool, the accelerometer is placed in a temperature control test box with a marble flat plate in the direction facing the sky and is connected with external strapdown inertial navigation through a cable, a temperature box control program is set according to a temperature variation curve, output pulses of the accelerometer are collected through an external strapdown inertial navigation collection system, the accelerometer is subjected to the temperature modeling test in the direction facing the ground after the test is finished, zero positions and scale factor temperature error models of three accelerometers are established according to modeling data facing the sky and the ground, and error compensation of the zero positions and the scale factors is carried out on the output of the accelerometer, so that high-precision accelerometer output is obtained.
In a strapdown inertial navigation system, a high-precision IF conversion circuit is designed and selectedThe asymmetry of the positive and negative scale factors is less than or equal to 30ppm, so the error can be ignored, and because the structural body and the tooling are all aluminum products, deformation can be generated when the temperature modeling of the accelerometer is carried out, if the testing equipment generates 2 arc seconds of deformation, which is equivalent to that 1 x 10 is introduced into the accelerometer- 5g, during temperature modeling, the deformation of the body and the tooling caused by the deformation of the body and the tooling can not be ignored, and the deformation can not be quantitatively expressed.
In order to accurately reflect the internal temperature of the accelerometer, a temperature sensor for measuring the temperature signal of the accelerometer is arranged near the internal head of the accelerometer, and the accelerometer is the most different from the traditional accelerometer in appearance: one terminal 11 is added on the basis of 10 insulated glass terminals, and the added insulated terminal 11 is used for three ports of a temperature sensor DS18B20 for temperature measurement together with the insulated terminals 9 and 10. As shown in fig. 2.
The method comprises the following specific steps:
a high-precision accelerometer temperature compensation method comprises the following steps:
(1) and (3) mounting three accelerometers in the strapdown inertial navigation on a marble tool. The marble fixture base body structure is a hexahedron, an accelerometer mounting groove is machined in the upper surface of the marble fixture base body structure, and a mounting hole is machined in the base body surface of the mounting groove and used for mounting and fixing an accelerometer. The planeness of the marble tooling is less than or equal to 2 arc seconds. The planeness of the mounting hole is less than or equal to 2 arc seconds. And a plurality of strapdown inertial navigation accelerometers can be installed on the marble tool. As shown in fig. 1.
(2) And placing the marble tool in a temperature control test box, and pointing the sensitive elements of the accelerometers to the sky after the marble tool is placed.
(3) The accelerometer is connected with an external strapdown inertial navigation data acquisition system through a cable, a temperature control test box door is closed, a temperature control program of the temperature control test box is set, the temperature of the temperature control test box is kept at the low temperature of 40 ℃ below zero for 3 hours, then the temperature of the temperature control test box is increased at the rising rate of 0.25 ℃/min, and the temperature is kept for 0.5 hour when the temperature reaches 70 ℃;
(4) after the temperature of the temperature test box is kept at the low temperature of 40 ℃ below zero for 3 hours, a power supply of an external strapdown inertial navigation data acquisition system is turned on, the output of the accelerometer is acquired in real time along with the temperature rise of the temperature test box, and the power supply of the external strapdown inertial navigation data acquisition system is turned off until the temperature is kept at the high temperature of 70 ℃ for 0.5 hour;
(5) setting the temperature of the temperature control test box to be 25 ℃ at normal temperature, opening the door of the temperature control test box after the temperature control test box reaches 25 ℃ at normal temperature, and changing the direction of the marble tool in the temperature control test box to enable the sensitive elements of the accelerometers to point to the ground;
(6) closing the door of the temperature control test box, setting a temperature control program of the temperature control test box, keeping the temperature of the temperature control test box at the low temperature of 40 ℃ below zero for 3 hours, then heating the temperature control test box at the rising rate of 0.25 ℃/min, and stabilizing for 0.5 hour when the temperature reaches 70 ℃;
(7) after the temperature of the temperature control test box is kept at the temperature of minus 40 ℃ for 3 hours, a power supply of an external strapdown inertial navigation data acquisition system is turned on, the output of the accelerometer is acquired in real time along with the temperature rise of the temperature control test box, and the power supply of the external strapdown inertial navigation data acquisition system is turned off until the temperature is kept at the high temperature of 70 ℃ for 0.5 hour;
(8) establishing a zero-position temperature model and a scale factor temperature error model of the accelerometer, fitting to obtain a zero-position curve of the accelerometer according to the outputs of the two groups of accelerometers and the zero-position temperature error model of the accelerometer, which are acquired by an external strapdown inertial navigation data acquisition system, and fitting to obtain a scale factor curve of the accelerometer according to the outputs of the two groups of accelerometers and the scale factor temperature error model of the accelerometer, which are acquired by the external strapdown inertial navigation data acquisition system;
the zero temperature error model for the accelerometer is as follows:
wherein A is0TxFor zero position of accelerometer in X direction, A0TyZero position of accelerometer in Y direction, A0TzIs the zero position of the accelerometer in the Z direction,
the output of the accelerometer in the X direction towards the sky, the output of the accelerometer in the Y direction towards the sky and the output of the accelerometer in the Z direction towards the sky are respectively;
respectively, the output of the accelerometer in the X direction facing the ground, the output of the accelerometer in the Y direction facing the ground and the output of the accelerometer in the Z direction facing the ground; kaxT、KayT、KazTThe scale factors of the accelerometer in the X direction, the scale factor of the accelerometer in the Y direction and the scale factor of the accelerometer in the Z direction are respectively;
KIFPxis the X-direction positive scale factor of the IF conversion circuit; kIFNxIs the negative scale factor of the X direction of the IF conversion circuit; kIFPyIs the Y-direction positive scale factor of the IF conversion circuit;
KIFNyis the Y-direction negative scale factor of the IF conversion circuit; kIFPzIs the Z-direction positive scale factor of the IF conversion circuit; kIFNzIs the Z-direction negative scaling factor of the IF conversion circuit.
The scale factor temperature error model for the accelerometer is as follows:
(9) and (4) carrying out temperature compensation on the output of the accelerometer by using the zero position curve and the scale factor curve of the accelerometer to obtain high-precision accelerometer output.
Example (b):
an accelerometer with temperature output is installed on a marble tool (figure 1) special for the accelerometer (figure 2), the accelerometer is placed in a temperature control test box with a marble flat plate in the direction of 'sky', and is connected with external strapdown inertial navigation through a cable (the schematic diagram is shown in figure 3), a temperature control test box door is closed, a temperature control test box control program is set according to a temperature change curve (figure 4), the temperature control test box is started to start cooling, the temperature of the temperature control test box is kept at the low temperature of 40 ℃ below zero for 3 hours, so that the temperature of three accelerometer components is consistent with the temperature of the temperature control test box, a product power supply is started, a strapdown inertial navigation data acquisition system is started, output pulses acquired by the external strapdown inertial navigation accelerometer in the temperature modeling test process are increased at the rising rate of 0.25 ℃/min, and the strapdown inertial navigation product is powered off after the temperature box reaches 70 ℃ and is stabilized for 0.5 hours again, after the test is finished, the accelerometer is subjected to the temperature modeling test once in the direction of facing the ground, and high-precision temperature compensation is realized according to the modeling data facing the sky and the ground and by combining the zero position and scale factor temperature error model established in the description.
After the temperature compensation is carried out on the fiber strapdown inertial navigation by the method, high and low temperature tests are carried out, and the results of the zero position, zero offset stability and scale factor of the accelerometer at the full temperature of the fiber strapdown inertial navigation are obtained as shown in the following table 1.
TABLE 1 Performance index of a certain inertial measurement unit after three accelerometers are modeled by high-precision accelerometer temperature
As can be seen from the above table, after the accelerometer is subjected to high-precision temperature compensation, the zero-offset and zero-offset stability (3 sigma) of the accelerometer is less than or equal to 0.05mg, and the scale factor is less than 50 ppm.
In order to eliminate the influence of installation errors on the precision of the accelerometer due to the fact that the external temperature changes, the test tool and the accelerometer installation body deform in the temperature modeling process, when the temperature modeling of the accelerometer is carried out, temperature modeling towards the sky and the earth is only carried out on three accelerometers in the strapdown inertial navigation, temperature error models of zero positions and scale factors of the three accelerometers are established according to data towards the sky and the earth, error compensation of the zero positions and the scale factors is carried out on the output of the accelerometers, and therefore high-precision output of the accelerometer is obtained.
FIG. 5 is a data comparison graph of accelerometer zero output before and after high accuracy temperature modeling of the accelerometer; FIG. 6 is a comparison of output data from accelerometer scaling factors before and after high accuracy temperature modeling of the accelerometer. After tests, the method of the invention is applied to the accelerometer with the zero offset temperature coefficient of less than or equal to 20 mu g/DEG C under the full temperature (-40 ℃ to +70 ℃), the zero change of more than 0.2mg under the full temperature and the monthly zero offset repeatability of less than or equal to 1.5 multiplied by 10 < -5 > g, and the precision of the zero offset stability (3 sigma) of less than or equal to 0.05mg under the full temperature (-40 ℃ to +70 ℃) is realized after the temperature compensation is carried out by the method of the invention.
The above description is only for the best mode of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.
Those skilled in the art will appreciate that the invention may be practiced without these specific details.
Claims (7)
1. A high-precision accelerometer temperature compensation method is characterized by comprising the following steps:
(1) mounting three accelerometers in the strapdown inertial navigation on a marble tool;
(2) placing the marble tool in a temperature control test box, and enabling the sensitive elements of the accelerometers to point to the sky after the marble tool is placed;
(3) the accelerometer is connected with an external strapdown inertial navigation data acquisition system through a cable, a temperature control test box door is closed, a temperature control program of the temperature control test box is set, the temperature of the temperature control test box is kept at the low temperature of 40 ℃ below zero for 3 hours, then the temperature of the temperature control test box is increased at the rising rate of 0.25 ℃/min, and the temperature is kept for 0.5 hour when the temperature reaches 70 ℃;
(4) after the temperature of the temperature test box is kept at the low temperature of 40 ℃ below zero for 3 hours, a power supply of an external strapdown inertial navigation data acquisition system is turned on, the output of the accelerometer is acquired in real time along with the temperature rise of the temperature test box, and the power supply of the external strapdown inertial navigation data acquisition system is turned off until the temperature is kept at the high temperature of 70 ℃ for 0.5 hour;
(5) setting the temperature of the temperature control test box to be 25 ℃ at normal temperature, opening the door of the temperature control test box after the temperature control test box reaches 25 ℃ at normal temperature, and changing the direction of the marble tool in the temperature control test box to enable the sensitive elements of the accelerometers to point to the ground;
(6) closing the door of the temperature control test box, setting a temperature control program of the temperature control test box, keeping the temperature of the temperature control test box at the low temperature of 40 ℃ below zero for 3 hours, then heating the temperature control test box at the rising rate of 0.25 ℃/min, and stabilizing for 0.5 hour when the temperature reaches 70 ℃;
(7) after the temperature of the temperature control test box is kept at the temperature of minus 40 ℃ for 3 hours, a power supply of an external strapdown inertial navigation data acquisition system is turned on, the output of the accelerometer is acquired in real time along with the temperature rise of the temperature control test box, and the power supply of the external strapdown inertial navigation data acquisition system is turned off until the temperature is kept at the high temperature of 70 ℃ for 0.5 hour;
(8) establishing a zero-position temperature model and a scale factor temperature error model of the accelerometer, fitting to obtain a zero-position curve of the accelerometer according to the outputs of the two groups of accelerometers and the zero-position temperature error model of the accelerometer, which are acquired by an external strapdown inertial navigation data acquisition system, and fitting to obtain a scale factor curve of the accelerometer according to the outputs of the two groups of accelerometers and the scale factor temperature error model of the accelerometer, which are acquired by the external strapdown inertial navigation data acquisition system;
the zero temperature error model for the accelerometer is as follows:
wherein A is0TxFor zero position of accelerometer in X direction, A0TyZero position of accelerometer in Y direction, A0TzIs the zero position of the accelerometer in the Z direction,
the output of the accelerometer in the X direction towards the sky, the output of the accelerometer in the Y direction towards the sky and the output of the accelerometer in the Z direction towards the sky are respectively;
respectively, the output of the accelerometer in the X direction facing the ground, the output of the accelerometer in the Y direction facing the ground and the output of the accelerometer in the Z direction facing the ground; kaxT、KayT、KazTThe scale factors of the accelerometer in the X direction, the scale factor of the accelerometer in the Y direction and the scale factor of the accelerometer in the Z direction are respectively;
KIFPxis the X-direction positive scale factor of the IF conversion circuit; kIFNxIs the negative scale factor of the X direction of the IF conversion circuit; kIFPyFor IF conversionConverting a Y-direction positive scale factor of the circuit; kIFNyIs the Y-direction negative scale factor of the IF conversion circuit; kIFPzIs the Z-direction positive scale factor of the IF conversion circuit; kIFNzIs a Z-direction negative scale factor of the IF conversion circuit;
the scale factor temperature error model for the accelerometer is as follows:
(9) and (4) carrying out temperature compensation on the output of the accelerometer by using the zero position curve and the scale factor curve of the accelerometer to obtain high-precision accelerometer output.
2. The method for compensating the temperature of the high-precision accelerometer according to claim 1, wherein: the marble frock matrix structure is the hexahedron, and the upper surface processing has accelerometer mounting groove, and processing has the mounting hole on mounting groove's basal body surface for the fixed accelerometer of installation.
3. The method for compensating the temperature of the high-precision accelerometer according to claim 2, wherein: the planeness of the marble tooling is less than or equal to 2 arc seconds.
4. The method for compensating the temperature of the high-precision accelerometer according to claim 3, wherein the method comprises the following steps: the flatness of the mounting hole is less than or equal to 2 arc seconds.
5. The method for compensating the temperature of the high-precision accelerometer according to claim 2, wherein: in the step (1), a plurality of accelerometers for strapdown inertial navigation can be mounted on the marble tool.
6. The method for compensating the temperature of the high-precision accelerometer according to claim 1, wherein: the accelerometer in the step (1) is additionally provided with an insulating terminal on the basis of 10 insulating glass terminals of a traditional accelerometer, meanwhile, the head of the accelerometer in the step (1) is packaged with a temperature sensor, three output pins of the temperature sensor are connected with three insulating glass terminals, and the three insulating glass terminals comprise the additionally arranged insulating glass terminals and two of the original 10 insulating glass terminals.
7. The method for compensating the temperature of the high-precision accelerometer according to claim 1, wherein: the accelerometer channel in the strapdown inertial navigation adopts a high-precision IF conversion circuit, and the asymmetry of positive and negative scale factors is less than or equal to 30 ppm.
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