High-precision temperature sensor calibration method in cryogenic environment

Abstract

The invention relates to the technical field of temperature measurement, in particular to a high-precision temperature sensor calibration method in a cryogenic environment, and the method comprises the steps: inserting a reference thermometer and a to-be-calibrated temperature sensor into a pre-constructed test cavity; adjusting the internal temperature of the test cavity to a preset first temperature, and measuring to obtain a first standard temperature and a first test temperature; calculating by adopting a recursive algorithm to obtain a set temperature sequence, sequentially adjusting the internal temperature of the test cavity according to the set temperature sequence, and measuring to obtain a standard temperature sequence and a test temperature sequence; fitting according to the standard temperature sequence and the test temperature sequence to obtain a temperature error function; and the temperature error function is built in the to-be-calibrated temperature sensor, and the measured value of the to-be-calibrated temperature sensor is calibrated. According to the invention, the calibration of the cryogenic environment temperature sensor is realized by automatically generating the set temperature sequence.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of temperature measurement, and particularly relates to a high-precision temperature sensor calibration method in a cryogenic environment. BACKGROUND

[0002] The cryogenic environment generally refers to an environment with a temperature of 77 Kelvin to 233 Kelvin. In the fields of aerospace, superconducting research, low-temperature physics and the like, temperature monitoring of the cryogenic environment has a decisive influence on system safety and experimental accuracy. Therefore, a high-precision temperature sensor with excellent low-temperature stability and reliable measurement is needed. However, the measurement result of the temperature sensor in the cryogenic environment is easily affected by nonlinear factors such as sensor signal lead heat leakage, resulting in parameter distortion. The mainstream temperature sensor calibration method currently adopts static constant point point-by-point calibration, that is, a reference thermometer and a temperature sensor to be calibrated are placed in a constant temperature test cavity, and the deviation value is recorded at a preset discrete temperature point to generate a segmented linear correction table. This method has the following defects: Firstly, the dynamic adaptability is poor. The segmented linear correction table cannot capture the complex nonlinear error change rule of the sensor in a wide temperature range. Secondly, the calibration efficiency is low. For different temperature sensors, due to different purposes, principles and manufacturing processes, there are high-precision temperature zones and low-precision regions. The prior art fails to adaptively distinguish the high-precision temperature zones and the low-precision regions, and a large number of static calibration points are set in a uniform manner, resulting in low efficiency. Thirdly, the calibration result is greatly affected by signal lead heat leakage. In the cryogenic environment, sensor signal lead heat leakage can cause signal distortion and the like.

[0003] Therefore, it is urgent to propose an intelligent calibration method which can autonomously generate an optimal temperature test sequence, reduce the influence of signal lead heat leakage, and accurately capture nonlinear errors in the cryogenic environment. SUMMARY

[0004] (1) Technical problem to be solved The purpose of the present application is to provide a high-precision temperature sensor calibration method in a cryogenic environment, which autonomously generates an optimal temperature test sequence, reduces the influence of signal lead heat leakage, and accurately captures nonlinear errors in temperature measurement in the cryogenic environment, thereby improving the calibration effect.

[0005] (2) Technical scheme To achieve the above purpose, the present application provides a high-precision temperature sensor calibration method in a cryogenic environment, which comprises the following steps: S1, inserting a reference thermometer and a temperature sensor to be calibrated into a pre-constructed test cavity.

[0006] S2, adjusting the temperature inside the test cavity to a preset first temperature; measuring the temperature inside the test cavity by referring to the thermometer and the temperature sensor to be calibrated respectively, and transmitting the first standard temperature and the first test temperature to the central processing unit through the wireless transmission device.

[0007] S3, calculating the set temperature sequence according to the first temperature, the first standard temperature and the first test temperature by using a recursive algorithm, adjusting the temperature inside the test cavity according to the set temperature sequence, and reading the test results of the thermometer and the temperature sensor to be calibrated through the wireless transmission device to obtain the standard temperature sequence and the test temperature sequence.

[0008] S4, fitting the temperature error function according to the standard temperature sequence and the test temperature sequence; and calibrating the measurement value of the temperature sensor to be calibrated by embedding the temperature error function into the temperature sensor to be calibrated.

[0009] Further, the test cavity adopts an adaptive temperature adjustment algorithm, so that the temperature at different spatial positions in the test cavity is uniform and can be adjusted according to the set value.

[0010] Further, the method of calculating the set temperature sequence according to the first temperature, the first standard temperature and the first test temperature by using a recursive algorithm, adjusting the temperature inside the test cavity according to the set temperature sequence, and reading the test results of the thermometer and the temperature sensor to be calibrated through the wireless transmission device to obtain the standard temperature sequence and the test temperature sequence comprises: S31, setting the cycle flag to 1.

[0011] S32, calculating the first error according to the first standard temperature and the first test temperature. The calculation formula of the first error is: wherein, Tn represents the first standard temperature, Tn represents the first test temperature, En represents the first error.

[0012] S33, calculating the first temperature according to the first error and the first temperature.

[0013] S34, adjusting the temperature inside the test cavity to the first temperature; the temperature inside the test cavity is measured by referring to the temperature meter and the temperature sensor to be calibrated respectively, and transmitted to the central processing unit through the wireless transmission device, to obtain the first standard temperature and the first test temperature.

[0014] S35, the value of the first is increased by 1; steps S32 to S35 are repeatedly executed until the value of the first reaches the value of the first N , and finally the first standard temperature to the first N standard temperature, the first test temperature to the first N test temperature are obtained; N represents the upper limit of the preset number of measurements; is an integer variable with a value of 1 to N .

[0015] S36, the first standard temperature to the first N standard temperature are combined to obtain a standard temperature sequence; and the first test temperature to the first N test temperature are combined to obtain a test temperature sequence.

[0016] Further, the method for calculating the first temperature according to the first error and the first temperature comprises: comparing the first error with a preset first error threshold , if the first error is greater than the first error threshold, the first temperature is calculated by using a first formula; if the first error is less than or equal to the first error threshold, the first temperature is calculated by using a second formula.

[0017] The first formula is: ; wherein, represents the first temperature, represents the first temperature, represents the preset upper limit of the constant temperature step.

[0018] The second formula is: ; wherein, represents the calculated first temperature step.

[0019] Further, the first The method for calculating temperature gradients is as follows: The third formula is used to calculate the first... Temperature gradient; the third formula is: ; in, This indicates a pre-set second error threshold; This indicates the lower limit of the pre-set constant temperature step.

[0020] Furthermore, the method for obtaining the temperature error function by fitting the standard temperature sequence and the test temperature sequence includes: According to the first standard temperature to the... N Standard temperature, first test temperature to the... N The test temperature calculation yielded the first calculation error up to the [missing value]. N Calculation error; where the first The formula for calculating the error is: ; in, Indicates the first Calculation error; the first calculation error is transferred to the second... N The calculation error combination yields the calculation error sequence.

[0021] Using the test temperature sequence as the independent variable and the calculated error sequence as the dependent variable, a temperature error function is obtained by fitting.

[0022] Furthermore, the method for fitting the temperature error function using the test temperature sequence as the independent variable and the calculated error sequence as the dependent variable includes: Construct a fitting function; the fitting function is expressed as: ; in, Represents the fitted function. This indicates the measured value of the temperature sensor to be calibrated, in Kelvin. Represents the cubic nonlinear coefficients. Represents the second-order nonlinear coefficients. Represents linear coefficients. This indicates the zero-point offset.

[0023] Using the test temperature sequence as the independent variable and the calculation error sequence as the dependent variable, a fitting algorithm was used to obtain the result. , , , The optimal values ​​are denoted as follows: , , , .

[0024] According to , , , The temperature error function is obtained, and the temperature error function is: ; Wherein, The temperature error function is represented.

[0025] Further, the method takes the test temperature sequence as the independent variable and the calculation error sequence as the dependent variable, and adopts a fitting algorithm to obtain the optimal values of , , , , respectively denoted as , , , The method comprises the following steps: Constructing an optimization objective function; the optimization objective function is: ; Taking the minimum value of the optimization objective function as the goal and taking the pre-set constraint condition as the constraint, the optimal values of , , , are calculated by using a particle swarm optimization algorithm, respectively denoted as , , , .

[0026] Further, the method of embedding the temperature error function into the temperature sensor to be calibrated and calibrating the measurement value of the temperature sensor to be calibrated comprises: The temperature error function is embedded into the temperature sensor to be calibrated, and the calibration temperature is calculated according to the measurement value of the temperature sensor to be calibrated; the calculation formula of the calibration temperature is: ; Wherein, The calibration temperature is represented.

[0027] (3) Advantageous effects Compared with the prior art, the advantageous effects of the present application are: 1. Reduce the influence of signal wire heat leakage by wireless transmission, improve the calibration accuracy.

[0028] 2. Based on the first temperature, the first standard temperature, and the first test temperature, a recursive algorithm is used to calculate the set temperature sequence. The internal temperature of the test chamber is then adjusted sequentially according to this set temperature sequence. The test results from the reference thermometer and the temperature sensor to be calibrated are read via a wireless transmission device to obtain the standard temperature sequence and the test temperature sequence. This method overcomes the inefficiency caused by setting static calibration points by autonomously generating the optimal temperature test sequence.

[0029] 3. Using the test temperature sequence as the independent variable and the calculated error sequence as the dependent variable, a temperature error function is obtained by fitting. This fitting function can adaptively capture the complex nonlinear error characteristics under cryogenic conditions. Attached Figure Description

[0030] Figure 1 This is a flowchart of a high-precision temperature sensor calibration method under cryogenic conditions according to Embodiment 1 of the present invention. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Before providing examples, it is necessary to describe the application scenarios of this invention. This embodiment is applied to the calibration of temperature sensors in cryogenic environments. During the calibration process, it autonomously generates the optimal temperature test sequence, reduces the impact of heat leakage from signal wires, and accurately captures nonlinear temperature measurement errors in cryogenic environments.

[0033] Example 1: As Figure 1 As shown, this embodiment provides a high-precision temperature sensor calibration method for cryogenic environments, the method comprising the following steps: S1, insert the reference thermometer and the temperature sensor to be calibrated into the pre-built test chamber.

[0034] S2, adjust the internal temperature of the test chamber to a preset first temperature; measure the internal temperature of the test chamber using a reference thermometer and a temperature sensor to be calibrated, and transmit the measurements to the central processing unit via a wireless transmission device to obtain the first standard temperature and the first test temperature.

[0035] S3, according to the first temperature, the first standard temperature, the first test temperature, a recursive algorithm is used to calculate a set temperature sequence, and the internal temperature of the test cavity is adjusted in sequence according to the set temperature sequence, and the test results of the reference thermometer and the temperature sensor to be calibrated are read through the wireless transmission device to obtain a standard temperature sequence and a test temperature sequence.

[0036] S4, a temperature error function is fitted according to the standard temperature sequence and the test temperature sequence; the temperature error function is built into the temperature sensor to be calibrated, and the measurement value of the temperature sensor to be calibrated is calibrated.

[0037] Exemplarily, the reference thermometer and the temperature sensor to be calibrated are inserted into the axial core area of the test cavity in parallel to obtain a coaxial installation structure without heat conduction interference; through the vacuum thermal insulation layer and the heat shield design, a stable temperature field with uniform temperature is obtained; by adjusting the insertion depth of the reference thermometer and the temperature sensor to be calibrated, it is ensured that the temperature sensing ends of the reference thermometer and the temperature sensor to be calibrated are in the core temperature field area of the test cavity. The reference thermometer is a thermometer capable of measuring the true value of temperature obtained through upper traceability verification.

[0038] The internal temperature of the cavity is adjusted to a preset first temperature through a liquid nitrogen refrigeration system. According to the temperature data measured by the reference thermometer and the temperature sensor to be calibrated synchronously, the central processing unit is transmitted in real time through the wireless transmission device to obtain the first standard temperature and the first test temperature. The error caused by the wire heat leakage in the traditional method is eliminated by the wireless transmission method. The unit of all temperature data in the embodiment is Kelvin.

[0039] According to the numerical relationship of the first temperature, the first standard temperature and the first test temperature, the set temperature sequence is dynamically calculated through the recursive algorithm. In the process of calculating the set temperature sequence, the measurement results of the reference thermometer and the temperature sensor to be calibrated need to be fed back to the recursive algorithm for calculation. According to the generated set temperature sequence, the internal temperature of the test cavity is adjusted in sequence, and the measurement results of the reference thermometer and the temperature sensor to be calibrated are obtained in real time through wireless transmission, and finally the standard temperature sequence and the test temperature sequence are obtained.

[0040] According to the numerical relationship of the standard temperature sequence and the test temperature sequence, the temperature error function is fitted. According to the temperature error function, the internal calibration program of the temperature sensor to be calibrated is written to obtain a calibrated temperature sensor with an internal error compensation mechanism, and the measurement value is automatically corrected.

[0041] Further, the test cavity adopts an adaptive temperature adjustment algorithm, so that the temperature at different spatial positions in the test cavity remains uniform and can be adjusted according to the set value.

[0042] Exemplarily, according to the thermodynamic distribution characteristics of the test cavity, the temperature gradients in the axial and radial directions of the cavity are monitored in real time through an adaptive temperature regulation algorithm. According to the gradient data, the power of the multi-section heater and the flow rate of the refrigerant are dynamically adjusted, so that the temperature uniformity at different spatial positions is stabilized within ±0.05 Kelvin. According to the externally input set temperature sequence, a fast response to the temperature adjustment instruction is realized through a feedforward-feedback composite control algorithm, and accurate tracking of the set value is realized.

[0043] Further, the method for calculating the set temperature sequence according to the first temperature, the first standard temperature and the first test temperature by using a recursive algorithm, adjusting the internal temperature of the test cavity according to the set temperature sequence, and reading the test results of the reference thermometer and the temperature sensor to be calibrated through the wireless transmission device to obtain the standard temperature sequence and the test temperature sequence comprises: S31, setting the cycle flag to 1.

[0044] S32, calculating the first error according to the first standard temperature and the first test temperature; the calculation formula of the first error is: ; wherein, represents the first standard temperature, represents the first test temperature, represents the first error.

[0045] S33, calculating the first temperature according to the first error and the first standard temperature.

[0046] S34, adjusting the internal temperature of the test cavity to the first temperature; the internal temperature of the test cavity is measured by the reference thermometer and the temperature sensor to be calibrated respectively, and is transmitted to the central processing unit through the wireless transmission device to obtain the first standard temperature and the first test temperature.

[0047] S35, increasing the value of by 1; the steps S32 to S35 are repeatedly executed until the value of reaches N , and finally the first standard temperature to the N standard temperature and the first test temperature to the N test temperature are obtained. NThis indicates the pre-set maximum number of measurements; The value is 1 to N Integer variables.

[0048] S36, from the first standard temperature to the second N Standard temperature combinations yield a standard temperature sequence; the first test temperature is then set to the next... N The test temperature combination yields the test temperature sequence.

[0049] For example, the preset upper limit for the number of measurements is 100. If a high level of accuracy is required for the final calibration result, a larger upper limit for the number of measurements can be set, but this will consume more computing power. If a lower level of accuracy is required for the final calibration result, a smaller upper limit for the number of measurements can be set, which will consume less computing power.

[0050] Furthermore, the statement based on the first Error, first Temperature calculation yields the first Temperature methods include: The first Error compared to a pre-set first error threshold Compare, if the first If the error is greater than the first error threshold, then the first formula is used to calculate the... Temperature; if the first If the error is less than or equal to the first error threshold, then the second formula is used to calculate the first error. temperature.

[0051] The first formula is: ; in, Indicates the first temperature, Indicates the first temperature, This indicates the upper limit of the pre-set constant temperature step.

[0052] The second formula is: ; in, Represents the calculated first... Temperature gradient.

[0053] For example, based on the comparison between the error value at the current temperature point and a first error threshold, a temperature adjustment strategy is dynamically selected to achieve efficient calibration. When the... When the error exceeds the first error threshold, it indicates that the temperature sensor exhibits significant distortion in this temperature range. This suggests that the temperature sensor itself is unsuitable for measuring this temperature range, and therefore, further computational effort should be avoided. The next temperature point is generated based on the upper limit of the constant temperature step, quickly locating the critical transition zone requiring fine-tuning by significantly traversing the distortion temperature range. When the... When the error is less than or equal to the first error threshold, it indicates that the temperature sensor has entered a critical transition zone requiring fine calibration. This is based on the dynamically calculated... The temperature step generates the next temperature point.

[0054] Furthermore, the first The method for calculating temperature gradients is as follows: The third formula is used to calculate the first... Temperature gradient; the third formula is: ; in, This indicates a pre-set second error threshold; This indicates the lower limit of the pre-set constant temperature step.

[0055] For example, establish the first Error and the first The mapping function of the temperature step. When the... When the error is between the second error threshold and the first error threshold, the first... Temperature gradient follows the first The error changes continuously and linearly. When the... When the error is less than or equal to the second error threshold, the lower limit of the constant temperature step is used as the step size.

[0056] Furthermore, the method for obtaining the temperature error function by fitting the standard temperature sequence and the test temperature sequence includes: According to the first standard temperature to the... N Standard temperature, first test temperature to the... N The test temperature calculation yielded the first calculation error up to the [missing value]. N Calculation error; where the first The formula for calculating the error is: ; in, Indicates the first Calculation error; the first calculation error is transferred to the second... N The calculation error combination yields the calculation error sequence.

[0057] Using the test temperature sequence as the independent variable and the calculated error sequence as the dependent variable, a temperature error function is obtained by fitting.

[0058] Further, the method for fitting the temperature error function with the test temperature sequence as the independent variable and the calculation error sequence as the dependent variable comprises: constructing a fitting function; the fitting function is represented as: ; wherein, represents the fitting function, represents the measurement value of the temperature sensor to be calibrated, in the unit of Kelvin; represents a cubic nonlinear coefficient, represents a quadratic nonlinear coefficient, represents a linear coefficient, represents a zero-point offset.

[0059] The optimal values of the fitting algorithm are fitted with the test temperature sequence as the independent variable and the calculation error sequence as the dependent variable, , , , are respectively recorded as , , , .

[0060] The temperature error function is obtained according to , , , , and the temperature error function is: ; wherein, represents the temperature error function.

[0061] Exemplarily, a mathematical mapping relationship model, i.e., a fitting function, is established with the measurement value of the temperature sensor to be calibrated as the input and the error value as the output. It is obtained through a large number of experiments and physical laws that the error value and the measurement value of the temperature sensor to be calibrated approximately present a cubic nonlinear relationship. Based on this, the fitting function is represented as a cubic polynomial. In the cubic polynomial, represents a cubic nonlinear coefficient, in the unit of Kelvin to the power of -2, represents a quadratic nonlinear coefficient, in the unit of Kelvin to the power of -1, represents a linear coefficient, dimensionless, represents zero-point offset, unit: Kelvin. According to the principle of minimizing fitting residual, the numerical solution of the coefficients of each term of the polynomial is calculated by an optimization algorithm, and the optimal combination of the coefficients is obtained, which makes the fitting curve and the error data point distribution most matched. According to the combination of the coefficients, the polynomial function expression is reconstructed, and the temperature error function which can accurately describe the nonlinear error law of the sensor to be calibrated in the cryogenic environment is obtained. The function can input any measurement value and output the corresponding error compensation in real time.

[0062] Further, the method of taking the test temperature sequence as the independent variable and the calculation error sequence as the dependent variable, using a fitting algorithm to fit the optimal values of 、 、 、 , respectively denoted as 、 、 、 includes: Constructing an optimization objective function; the optimization objective function is: ; Taking the minimum value of the optimization objective function as the target and the pre-set constraint condition as the constraint, the optimal values of 、 、 、 are calculated by using a particle swarm optimization algorithm, respectively denoted as 、 、 、 .

[0063] Further, the method of embedding the temperature error function into the temperature sensor to be calibrated and calibrating the measurement value of the temperature sensor to be calibrated includes: Embedding the temperature error function into the temperature sensor to be calibrated, and calculating the calibration temperature according to the measurement value of the temperature sensor to be calibrated; the calculation formula of the calibration temperature is: ; Wherein, represents the calibration temperature.

[0064] Exemplarily, a temperature error function is written into a non-volatile storage unit of the temperature sensor to be calibrated through a burning interface, so as to obtain an embedded hardware structure with self-calibration capability. A measurement value of the temperature sensor to be calibrated collected in real time by the sensor is input into the temperature error function for operation, so as to obtain an error compensation quantity corresponding to a current temperature point. According to an arithmetic logic of "the measurement value of the temperature sensor to be calibrated minus the error compensation quantity", a subtraction operation is executed in real time by a built-in microprocessor, so as to obtain a calibrated physical temperature true value. According to the true value, an original signal output is replaced, so as to obtain a calibrated temperature eliminating a deep cooling nonlinear error, and an online self-calibration function without external intervention is realized.

[0065] Finally, it should be noted that although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments or equivalently replace part of the technical features, and any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A high-precision temperature sensor calibration method in a cryogenic environment, characterized by, The method comprises the following steps: S1, inserting a reference thermometer and a temperature sensor to be calibrated into a pre-constructed test cavity; S2, adjusting the temperature inside the test cavity to a pre-set first temperature; measuring the temperature inside the test cavity by the reference thermometer and the temperature sensor to be calibrated respectively, and transmitting the test results to the central processing unit through the wireless transmission device to obtain a first standard temperature and a first test temperature; S3, calculating a set temperature sequence according to the first temperature, the first standard temperature and the first test temperature by using a recursive algorithm, adjusting the temperature inside the test cavity according to the set temperature sequence in turn, and reading the test results of the reference thermometer and the temperature sensor to be calibrated through the wireless transmission device to obtain a standard temperature sequence and a test temperature sequence; S4, fitting a temperature error function according to the standard temperature sequence and the test temperature sequence; and embedding the temperature error function into the temperature sensor to be calibrated to calibrate the measurement value of the temperature sensor to be calibrated.

2. A high-precision temperature sensor calibration method in a cryogenic environment as claimed in claim 1, characterized in that, The test cavity adopts an adaptive temperature adjustment algorithm, so that the temperature at different spatial positions in the test cavity is uniform and can be adjusted according to the set value.

3. A high-precision temperature sensor calibration method in a cryogenic environment as claimed in claim 2, characterized in that, The method for calculating the set temperature sequence according to the first temperature, the first standard temperature and the first test temperature by using the recursive algorithm, adjusting the temperature inside the test cavity according to the set temperature sequence in turn, and reading the test results of the reference thermometer and the temperature sensor to be calibrated through the wireless transmission device to obtain the standard temperature sequence and the test temperature sequence comprises: S31, set the cycle flag to 1; S32, according to the first standard temperature, the first test temperature, the first error; the calculation formula of the first error is: ； wherein, represents the standard temperature, represents the test temperature, represents the error; S33, according to the first error, the first temperature calculation of the first temperature; S34, adjusting the temperature inside the test chamber to the first temperature; measuring the temperature inside the test chamber by a reference thermometer and the temperature sensor to be calibrated respectively, and transmitting to the central processing unit by the wireless transmission device to obtain the first standard temperature and the first test temperature; S35, The value is increased by 1; steps S32 to S35 are repeated until... The value reaches N Finally, the first standard temperature was obtained up to the [number missing]. N Standard temperature, first test temperature to the... N Test temperature; N This indicates the pre-set maximum number of measurements; The value is 1 to N Integer variables; S36, from the first standard temperature to the second N Standard temperature combinations yield a standard temperature sequence; the first test temperature is then set to the next... N The test temperature combination yields the test temperature sequence.

4. A high-precision temperature sensor calibration method in a cryogenic environment as claimed in claim 3, characterized in that, The method according to the first error, the first temperature calculation of the first The method of calculating the temperature comprises: The first Error compared to a pre-set first error threshold Compare, if the first If the error is greater than the first error threshold, then the first formula is used to calculate the... Temperature; if the first If the error is less than or equal to the first error threshold, then the second formula is used to calculate the first error. temperature; The first formula is: ； wherein, represents the temperature, represents the temperature, represents the upper limit of a constant temperature step set in advance; The second formula is: ； wherein, represents the calculated first temperature step.

5. A high-precision temperature sensor calibration method in a cryogenic environment as claimed in claim 4, characterized in that, The first The temperature step is calculated by: The third formula is used to calculate the first temperature steps; the third formula is: ; wherein represents a pre-set second error threshold value; represents a pre-set lower limit of constant temperature step.

6. A high-precision temperature sensor calibration method in a cryogenic environment as claimed in claim 5, characterized in that, The method for fitting the temperature error function according to the standard temperature sequence and the test temperature sequence comprises: According to the first standard temperature to the... N Standard temperature, first test temperature to the... N The test temperature calculation yielded the first calculation error up to the [missing value]. N Calculation error; where the first The formula for calculating the error is: ； wherein, denotes the calculating errors; calculating the first error to the N calculating the error combination to obtain the error sequence Taking the test temperature sequence as the independent variable and the calculation error sequence as the dependent variable, the temperature error function is fitted.

7. A high-precision temperature sensor calibration method in a cryogenic environment as claimed in claim 6, characterized in that, The method for fitting the temperature error function by taking the test temperature sequence as the independent variable and the calculation error sequence as the dependent variable comprises: Constructing a fitting function; the fitting function is expressed as: ； wherein represents the fitted function, represents the measured value of the temperature sensor to be calibrated in Kelvin; represents the cubic non-linear coefficient, represents the quadratic non-linear coefficient, represents the linear coefficient, represents the zero-point offset; Taking the test temperature sequence as the independent variable and the calculation error sequence as the dependent variable, the optimal value of the fitting algorithm is fitted to obtain 、 、 、 , respectively denoted as 、 、 、 ; According to , , , a temperature error function is obtained, which is: ； wherein denotes the temperature error function.

8. A high-precision temperature sensor calibration method in a cryogenic environment as claimed in claim 7, characterized in that, The method comprises the following steps: taking the test temperature sequence as an independent variable, taking the calculation error sequence as a dependent variable, and adopting a fitting algorithm to obtain the optimal value of 、 、 、 , respectively denoted as 、 、 、 . Constructing an optimization objective function; the optimization objective function is: ； With the optimization objective function value minimum as the goal, with the pre-set constraint condition as the constraint, the particle swarm optimization algorithm is used to calculate the optimal value of 、 、 、 , respectively denoted as 、 、 、 .

9. A high-precision temperature sensor calibration method in a cryogenic environment as claimed in claim 8, characterized in that, The method for embedding the temperature error function into the temperature sensor to be calibrated to calibrate the measurement value of the temperature sensor to be calibrated comprises: The temperature error function is embedded into the temperature sensor to be calibrated, and a calibrated temperature is calculated according to the measurement value of the temperature sensor to be calibrated; the calculation formula of the calibrated temperature is: ； wherein represents the calibration temperature.

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