阅读说明：本技术 一种基于精确微型相变固定点黑体模型的太空校准方法 (Space calibration method based on accurate miniature phase-change fixed point blackbody model ) 是由 郝小鹏 司马瑞衡 宋健 于 2019-11-06 设计创作，主要内容包括：本发明提供了一种基于精确微型相变固定点黑体模型的太空校准方法。利用准确的数值模型,对微型相变固定点黑体熔点温度及内部携带的铂电阻温度计进行校准,以应对因实验条件变化而导致的黑体熔点温度变化。首先根据黑体与固定结构建立准确的数值模型。通过辐射温度光路调整,将固定点黑体熔点温度量值传递至微型相变固定点黑体,通过插值法获得微型相变固定点黑体在镓点处较为准确的相变温度数据。通过这一温度数据对模型完成修正,以消除粗糙接触面、空隙、不准确材料参数对模型的影响。最后,利用该修正模型计算获得不同固定点处熔点温度。本发明可应用于在轨卫星等无法进行标准温度测量的情况。(The invention provides a space calibration method based on a precise miniature phase-change fixed point blackbody model. The melting point temperature of the black body of the miniature phase change fixed point and a platinum resistance thermometer carried in the black body are calibrated by using an accurate numerical model so as to cope with the change of the melting point temperature of the black body caused by the change of experimental conditions. Firstly, an accurate numerical model is established according to the blackbody and the fixed structure. The melting point temperature value of the fixed point black body is transmitted to the miniature phase change fixed point black body through radiation temperature light path adjustment, and accurate phase change temperature data of the miniature phase change fixed point black body at a gallium point is obtained through an interpolation method. The model is corrected by the temperature data so as to eliminate the influence of rough contact surface, gaps and inaccurate material parameters on the model. And finally, calculating by using the correction model to obtain the melting point temperatures at different fixed points. The invention can be applied to the situation that standard temperature measurement can not be carried out by on-orbit satellites and the like.)

1. A space calibration method based on an accurate miniature phase change fixed point blackbody model comprises the following steps:

step 1: the magnitude is transmitted through the radiation thermometer, the radiation thermometer obtains the temperature of the fixed point black body, the light path is adjusted through the rotating shaft mirror, and the radiation thermometer obtains the temperature of the miniature phase change fixed point black body;

step 2: an interpolation function is carried out on the temperature of the transmitted accurate fixed point black body at the gallium point and the inaccurate temperature point of the miniature phase change fixed point black body, and a relatively accurate phase change temperature curve of the miniature phase change fixed point black body near the gallium point is obtained by measuring a voltage signal and the interpolation function through a radiation thermometer;

and step 3: correcting the model through the accurate phase transition temperature curve to eliminate the difference between unknown heat conduction parameters such as materials, gaps, contact and the like and an ideal model so as to obtain an accurate numerical model;

and 4, step 4: the melting point temperature of the miniature phase change fixed point black body at different fixed points under different experimental conditions is obtained through accurate numerical model calculation, so that the internal platinum resistance thermometer is corrected.

2. A space correction method as defined in claim 1 wherein: and step 3, correcting the model through a group of temperature curves to eliminate the difference between unknown heat conduction parameters such as materials, gaps, contact and the like and an ideal model.

3. A space correction method as defined in claim 1 wherein: and in the step 1, the magnitude is transmitted through the radiation thermometer, the light path is adjusted through the rotating shaft mirror, and the magnitude of the fixed point black body is transmitted to the miniature phase change fixed point black body.

4. A space correction method as defined in claim 1 wherein: the numerical model in the step 4 is a numerical model which takes the micro phase change fixed point black body and the external fixed structure as analysis objects and constructs the micro phase change fixed point black body and the external fixed structure.

Technical Field

The invention relates to the technical field of satellite earth observation, in particular to a space calibration method based on a precise miniature phase-change fixed point blackbody model.

Background

Earth observation is one of the most important application directions of satellite technology, and plays an indispensable role in a series of fields such as meteorological forecasting, homeland general survey, crop estimation, forest investigation, geological prospecting, ocean forecasting, environmental protection, disaster monitoring, urban planning, mapping and surveying and mapping, military reconnaissance, missile early warning and battlefield assessment.

Long-term, accurate detection of ground information from space measurements is a difficult task. In the space environment, the measured temperature value of the satellite gradually deviates from the actual temperature, which not only seriously affects the observation precision and the effective observation service life of the satellite, but also is difficult to establish an undissolvable climate record for long-term trend prediction of a climate model. In addition, the observation instruments which are not accurately calibrated in various countries have measurement differences and related uncertainty, and the remote sensing satellite which is lack of consistency is difficult to meet the requirement of constructing a ground observation system. Global, (systematic) socialized trends were observed for the land. For this purpose, the united nations climate organization has published a document in which the requirements for obtaining basic climate data records (i.e. long-term data records) are specified: high quality observation instruments are used, which have sufficient stability and accuracy for climate monitoring.

Typically, calibration of radiometric instruments is done by black body. According to the Planck equation, the spectral radiance of a black body is represented by the temperature and the wavelength of the black body, the correction Sakuma-Hattori interpolation equation of the Planck law provides a calibration scheme of a radiometer, and the radiometer can be calibrated by using a group of black bodies with known emissivity and temperature. However, in the space environment, accurate acquisition of the black body temperature is difficult, and over a period of up to several years, the contact temperature sensor gradually shifts from the true temperature. Therefore, the micro phase change fixed point blackbody which can automatically calibrate multiple temperature points and can be traced to ITS-90 international temperature standard draws more and more attention. In the research of the space blackbody radiation source, a blackbody cavity carries a plurality of miniature crucibles filled with different fixed point materials, the fixed point defined by ITS-90 or the secondary defined fixed point is combined with a blackbody with radiation temperature standard, and a temperature sensor in the blackbody is calibrated through the known melting point temperature of the fixed point. A transmission chain of the brightness temperature of the space infrared radiation reference source and the international temperature scale value is established. Related researches are carried out on the American Earth observation plan (EOS) project, the climate absolute brightness and reflection observation plan 'CLARREO', the Russian Geostationary Orbit Meteorological Satellite (GOMS) project, the Chinese 'wind cloud' series earth observation satellite and other projects, and the metering institutions of China, American, Japanese and Germany families, and the related researches are expected to become the core technology for high-precision calibration of the infrared remote sensing observation space in the future

The platinum resistance thermometer carried inside is calibrated by establishing a connection with a fixed point in the black body through heat conduction. Numerous experiments have shown that the blackbody melting point temperature is also influenced by the device structure and experimental conditions on a fine scale. Particularly, in the on-orbit situation, the fixing mode, the ambient temperature and the temperature control mode of the black body in the satellite can be greatly different from the ground experiment conditions, and the conditions the same as those in the laboratory are difficult to be accurately realized. Laboratory measurements are no longer applicable and the scarce experimental conditions in satellites make testing difficult.

Disclosure of Invention

The invention aims to provide a space calibration method based on an accurate miniature phase change fixed point black body model, which can solve the problem of inaccurate calibration of a miniature phase change fixed point black body in a satellite due to the change of experimental conditions so as to meet the requirement of high-precision radiation calibration.

In order to achieve the purpose, the invention adopts the following technical scheme:

and constructing a miniature phase change fixed point blackbody numerical model, verifying the accuracy of the model and ensuring the precision of the model.

Because the model uses ideal condition parameters and lacks of real rough contact surface, gap and material parameter setting, an accurate experimental temperature curve is obtained to correct the model parameters.

The invention provides a space calibration method based on a precise miniature phase change fixed point blackbody model, which comprises the following steps:

step 1: the magnitude is transmitted through the radiation thermometer, the radiation thermometer obtains the temperature of the fixed point black body, the light path is adjusted through the rotating shaft mirror, and the radiation thermometer obtains the temperature of the miniature phase change fixed point black body;

step 2: an interpolation function is carried out on the temperature of the transmitted accurate fixed point black body at the gallium point and the inaccurate temperature point of the miniature phase change fixed point black body, and a relatively accurate phase change temperature curve of the miniature phase change fixed point black body near the gallium point is obtained by measuring a voltage signal and the interpolation function through a radiation thermometer;

and step 3: and correcting the model through the accurate phase-change temperature curve to eliminate the difference between unknown heat conduction parameters such as materials, gaps, contact and the like and an ideal model so as to obtain an accurate numerical model.

And 4, step 4: the melting point temperature of the miniature phase change fixed point black body at different fixed points under different experimental conditions is obtained through accurate numerical model calculation, so that the internal platinum resistance thermometer is corrected.

Step 3 includes correcting the model through a set of temperature curves to eliminate the difference between unknown heat conduction parameters such as material, gap, contact and the like and an ideal model.

In the step 1, the magnitude is transmitted through the radiation thermometer, the light path is adjusted through the rotating shaft mirror, and the magnitude of the fixed point black body is transmitted to the miniature phase change fixed point black body.

And 4, constructing the numerical model of the micro phase change fixed point black body and the external fixed structure by taking the micro phase change fixed point black body and the external fixed structure as analysis objects.

Under the on-orbit condition, the fixing mode, the environment temperature and the temperature control mode of the black body in the satellite can be greatly different from the experimental conditions, the same conditions as a laboratory are difficult to accurately realize, and the melting point temperature of the black body can be greatly changed. The accurate numerical model has the advantage that a more accurate phase-change temperature curve can be calculated at different fixed points. To obtain an accurate numerical model, a set of accurate measurement experiment results is required to correct the model to eliminate the difference between unknown thermal conductivity parameters such as material, gap, contact, etc. and an ideal model. However, in the on-track radiation calibration system, the temperature measured by the miniature phase-change fixed-point black body has a large error due to the change of experimental conditions, and only the temperature measured by the fixed-point black body is accurate. To obtain an accurate set of measurements. The magnitude transmission can be carried out through the radiation thermometer, the light path is adjusted through the rotating shaft mirror, the magnitude of the fixed point black body is transmitted to the miniature phase change fixed point black body, interpolation calculation is carried out on the transmitted accurate gallium point temperature and the inaccurate temperature owned by the miniature phase change fixed point black body, and therefore the accurate phase change temperature curve of the miniature phase change fixed point black body close to the gallium point is obtained. The interpolation method and the selection of the melting point temperature of the micro phase change fixed point black body at the gallium point aim to reduce the influence of the error of interpolation endpoint data on the result. And correcting the model according to the obtained more accurate temperature curve. And then obtaining the accurate melting point temperature of the miniature phase change fixed point black body at different fixed points under different experimental conditions to correct a platinum resistance thermometer in the miniature phase change fixed point black body.

Drawings

FIG. 1 is a schematic flow chart of a space calibration method based on a precise miniature phase change fixed point blackbody model according to the present invention;

FIG. 2 is a schematic diagram of an in-orbit radiation calibration apparatus;

FIG. 3 is a schematic diagram of a space calibration method based on a precise miniature phase change fixed point blackbody model.

Detailed Description

For the purpose of facilitating understanding of the present invention, the following description is given of embodiments of the present invention with reference to the accompanying drawings, and it will be understood by those skilled in the art that the following descriptions are provided for convenience of explanation and are not intended to limit the scope of the present invention.

Space observation satellites usually use infrared radiometers to observe the ground, and obtain high-precision and high-spatial-resolution ground information through an atmospheric radiation model. During the working process of the infrared radiation thermometer, the brightness signal needs to be converted into an electric signal, and then the corresponding relation between the detector voltage and the target temperature is established by using an interpolation method. For ease of illustration, the radiometer parameters are exemplified by the Miami model 2001 Infrared radiometer, although other types of Infrared radiometers may be used.

FIG. 1 is a schematic flow chart of a space calibration method based on a precise miniature phase-change fixed-point blackbody model according to the present invention.

First, a finite element simulation model is constructed based on the analysis object. Specifically, the micro phase change fixed point black body and the external fixed structure are used as analysis objects, and a numerical model of the micro phase change fixed point black body and the external fixed structure is constructed. The construction process of the numerical model comprises the steps of establishing a geometric model according to an object structure; the material parameters of the finite element simulation model component are set according to the physical properties of the object using materials. Setting physical fields and boundary conditions, which may include boundary heat sources, boundary temperature sources, boundary heat losses, heat fluxes, thermal contacts, boundary radiation, etc. And carrying out meshing on the finite element simulation model. And setting a solver and performing solving calculation. The advantage of the accurate numerical model is that a more accurate phase transition temperature curve can be calculated at different fixed points.

However, in the on-orbit radiation calibration system, the temperature measured by the miniature phase-change fixed point black body may change due to the change of experimental conditions, so that a large error exists, and only the temperature measured by the fixed point black body is relatively accurate. To obtain an accurate numerical model, a set of accurate measurement experiment results is required to correct the model to eliminate the difference between unknown thermal conductivity parameters such as material, gap, contact, etc. and an ideal model. And comparing the data with the laboratory result of the miniature phase change fixed point, verifying the accuracy of the model and ensuring the precision of the model.

To obtain an accurate set of measurements. The magnitude transmission can be carried out through the radiation thermometer, the light path is adjusted through the rotating shaft mirror, the magnitude of the fixed point black body is transmitted to the miniature phase change fixed point black body, interpolation calculation is carried out on the transmitted accurate gallium point temperature and the inaccurate temperature owned by the miniature phase change fixed point black body, and therefore a relatively accurate phase change temperature curve of the miniature phase change fixed point black body near the gallium point is obtained. The interpolation method and the selection of the melting point temperature of the micro phase change fixed point black body at the gallium point are used for reducing the influence of the error of interpolation endpoint data on the result. And correcting the model according to the obtained more accurate temperature curve. And then obtaining the accurate melting point temperature of the miniature phase change fixed point black body at different fixed points under different experimental conditions to correct a platinum resistance thermometer in the miniature phase change fixed point black body.

Considering that all the models are ideal condition parameters, and lack of real rough contact surface, gap and material parameter settings, the model parameters need to be corrected by a set of accurate experimental temperature curves, and how to obtain an accurate set of measurement results is further described below:

as shown in fig. 2, the calibration system for the observation satellite includes two space reference radiation sources, namely a fixed point black body and a micro phase change fixed point black body, and can calibrate a platinum resistance thermometer carried in the black body at a gallium point and a plurality of fixed points through a phase change material carried in the calibration system. The optical path switching is carried out through the rotating shaft mirror, so that the radiometer obtains optical information of different targets. The fixed point black body is preferably a gallium fixed point black body.

And step A, adjusting the rotating shaft mirror, and switching the light path to the gallium fixed point black body. Obtaining signal voltage and corresponding melting point temperature T at the gallium fixed point calibration gallium fixed point of the gallium fixed point black body through a radiation thermometer_Ga，T_GaMay be considered equal to true value 302.9146K.

And B, adjusting the rotating shaft mirror, and switching the light path to the miniature phase change fixed point black body. Obtaining signal voltage V of melting point temperature at non-gallium point (such as fixed point of phenyl salicylate) by radiation thermometer₁. Here black body true temperature T₁Unknown, Only known laboratory measurements T₁′，T₁' in the vicinity of 315K, the error caused by a change in condition is Δ T₁′。

C, measuring the phase change curve of the miniature phase change fixed point black body at the gallium fixed point, and measuring the voltage value V corresponding to the melting point temperature₂. True temperature T of black body₂Unknown, laboratory results are T₂′，T₂' near 304K, the error due to a change in conditions is Δ T₂'. From V_Ga-T_GaAnd V₁-T₁' an interpolation function between two points is carried out to calibrate the interval. Measuring micro phase change fixed point black body on gallium solidMeasuring the voltage value V corresponding to the phase transition temperature by using the phase transition curve at the fixed point₂. From a voltage value V₂And the upper interpolation function can obtain the phase transition temperature T₂", the error caused by a change in condition is Δ T₂”，

The accurate temperature value T of the micro phase change fixed point blackbody at the gallium point can be obtained by the steps A-C₂"; the model is corrected according to the experimental temperature to eliminate the influence of rough contact surface, gap and inaccurate material parameters on the model.

And C, obtaining a more accurate phase change temperature value of the micro phase change fixed point black body near the gallium point, and correcting the model according to the experimental temperature to eliminate the influence of the rough contact surface, the gap and inaccurate material parameters on the model. Obtaining inflection point temperature of other material at fixed point by numerical model, such as temperature inflection point T at fixed point of phenyl salicylate₁". If the error caused by the change in the condition before correction is Δ T₁' 50mk, the corrected total error

Including errors in the model itselfAnd correcting the error Δ T of the selected reference experimental data₂”。ΔT₂"is the error in the model using the parameters, about 0.8mk,

the error of the model itself is 3.5mk, the corrected total error Δ T₁"is 4.3 mk.

The melting point temperature of the miniature phase change fixed point black body at other fixed points is obtained by using a simulation model, and the phase change temperature values of different fixed points under different experimental conditions (such as environment temperature and heating power) are obtained by using an accurate model.

The platinum resistance thermometer in the black body was modified by obtaining the temperature.

It is to be understood that while the present invention has been described in conjunction with the preferred embodiments thereof, it is not intended to limit the invention to those embodiments. It will be apparent to those skilled in the art from this disclosure that many changes and modifications can be made, or equivalents modified, in the embodiments of the invention without departing from the scope of the invention. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention are still within the scope of the protection of the technical solution of the present invention, unless the contents of the technical solution of the present invention are departed.

Any simple modification, equivalent change and modification made by the above embodiments still fall within the protection scope of the technical scheme of the present invention.