Device and method for calibrating temperature measurement error of thermal calibration source of radiometer

Abstract

The invention relates to the technical field of temperature measurement, in particular to a radiometer thermal calibration source temperature measurement error calibration device and method. The device comprises a plurality of platinum resistor temperature measurement sensors, a constant current source module, a temperature measurement channel switching module, an environment temperature acquisition module, an aging error calibration module, an amplification filtering module, an AD conversion module and a microprocessor system module, the constant current source module is electrically connected with the temperature measurement channel switching module; the aging error calibration module, the environment temperature acquisition module and the amplification filtering module are electrically connected with the temperature measurement channel switching module; the AD conversion module is electrically connected with the amplification filtering module; and the microprocessor system module is electrically connected with the AD conversion module. According to the invention, the quantitative relation between the output temperature of the sensor and the acquired value is established, the measurement error caused by parameter difference of components, temperature drift and long-term working aging is greatly reduced, and the measurement accuracy is improved.

Description

Technical Field

[0001] The present application relates to the technical field of temperature measurement, and in particular to a device and method for calibrating temperature measurement errors of a radiometer thermal calibration source. Background Art

[0002] The thermal calibration source of the satellite-borne microwave radiometer provides high-precision and high-stability standard radiation brightness temperature signals for the microwave detection payload of the remote sensing satellite, realizes the real-time calibration of the microwave radiometer on orbit, and is a key equipment for improving the calibration accuracy of microwave remote sensing detection.

[0003] The thermal calibration source consists of two devices: a radiation source and a temperature measurement controller. The temperature provided by the thermal calibration source is actually the physical temperature of the radiation source, and the temperature measurement controller achieves high-precision measurement and control of the physical temperature of the radiation source. Therefore, it is very important to achieve high-precision measurement of the physical temperature of the radiation source black body, which is directly related to the on-orbit calibration accuracy of the microwave radiometer.

[0004] To achieve high-precision measurement of the physical temperature of the thermal calibration source radiation source, many factors are involved, including temperature sensors, temperature measurement circuits, test calibration devices, and error calibration methods. Error calibration is a key step in achieving high-precision acquisition. Summary of the invention

[0005] The present application provides a device and method for calibrating the temperature measurement error of a thermal calibration source of a radiometer, which solves the problem of calibrating the on-orbit drift error of a thermal calibration source of a satellite-borne microwave radiometer and realizes high-precision acquisition of the temperature of the thermal calibration source of a satellite-borne microwave radiometer.

[0006] In order to achieve the above-mentioned purpose, the present application provides a temperature measurement error calibration device for a radiometer thermal calibration source, comprising a platinum resistance temperature sensor, a constant current source module, a temperature measurement channel switching module, an ambient temperature acquisition module, an aging error calibration module, an amplification and filtering module, an AD conversion module and a microprocessor system module, wherein: a plurality of platinum resistance temperature sensors are provided, and the plurality of platinum resistance temperature sensors are all provided inside the radiation source, and each platinum resistance temperature sensor is electrically connected to the temperature measurement channel switching module; the constant current source module is electrically connected to the temperature measurement channel switching module for providing a constant current drive; the aging error calibration module, the ambient temperature acquisition module and the amplification and filtering module are all electrically connected to the temperature measurement channel switching module; the AD conversion module is electrically connected to the amplification and filtering module; and the microprocessor system module is electrically connected to the AD conversion module.

[0007] Furthermore, a multi-channel high-voltage analog switch device is arranged inside the temperature measurement channel switching module.

[0008] Furthermore, the constant current provided by the constant current source module is less than 1 mA.

[0009] Furthermore, when the ambient temperature acquisition module acquires temperature, the deviation is less than ±1°C.

[0010] Furthermore, the drift value of the aging calibration module is smaller than the drift value of the platinum resistance temperature sensor itself.

[0011] Furthermore, the main core device of the AD conversion module is the 16-bit AD976ASD.

[0012] In addition, the present application also provides a method for calibrating a temperature measurement error device using a radiometer thermal calibration source, comprising the following steps:

[0013] Step 1: Determine the temperature measurement range, measurement accuracy and on-orbit working environment temperature of the device;

[0014] Step 2: Place the device in a high-precision temperature test chamber, set the chamber temperature to 25°C, put the microprocessor system module in calibration mode, collect temperature data, and the collected value is the source code value output by the AD conversion module;

[0015] Step 3: Use a high-precision resistance box to simulate the graduation table of platinum resistance, set the resistance value at every 5K interval within the temperature measurement range, collect and record it through the microprocessor system module, and obtain the collected temperature, platinum resistance value, and collected hexadecimal source code value;

[0016] Step 4: Repeat the operation in step 3 for each channel to complete the data collection and storage of all temperature measurement channels;

[0017] Step 5: Fit the AD acquisition value collected by each temperature measurement channel with the corresponding nominal temperature value data by a cubic polynomial to calculate the calibration parameters of each channel;

[0018] Step 6: Bind the obtained calibration parameters of all temperature measurement channels into the microprocessor system module; within the temperature measurement range, use the nominal resistance value of the resistance box as input to collect temperature, and at an ambient temperature of 25°C, check whether the temperature measurement accuracy and range meet the requirements; if not, re-execute steps 3 to 6;

[0019] Step 7: Adjust the temperature of the temperature test box, starting with the lower limit of the actual working environment temperature. After the environment temperature is balanced and stabilized for 1 hour, perform temperature measurement accuracy tests on all temperature measurement channels according to step 6, and record the environment temperature value fed back by the environment temperature acquisition module, the temperature acquisition values ​​of each channel, and the acquisition values ​​of the aging error calibration module;

[0020] Step 8: Raise the temperature of the temperature test chamber by 5°C, and repeat the operation in step 7 until the temperature of the temperature test chamber reaches the upper limit of the device operating temperature;

[0021] Step 9: Process the data, divide the temperature measurement range into three sections: upper, middle and lower, take the temperature error calibration values ​​respectively, and establish a quadratic polynomial between the ambient temperature and the temperature error calibration value, bind the temperature calibration mathematical model and parameters into the microprocessor system module, and complete the temperature drift error calibration;

[0022] Step 10: By collecting the standard reference resistance in the aging error calibration module, the offset of the standard reference temperature is obtained to realize the aging error calibration of the temperature measurement data of the multi-channel platinum resistance temperature measurement sensor;

[0023] Step 11: Set the temperature of the temperature test box to the upper, middle and lower ranges of the working environment temperature of the self-calibration device, use the standard resistance value of the resistance box as input to collect temperature, and check whether the temperature measurement range and accuracy meet the requirements. If not, repeat the above steps until the requirements are met.

[0024] The present application provides a radiometer thermal calibration source temperature measurement error calibration device and method, which has the following beneficial effects:

[0025] The present application establishes a quantitative relationship between the sensor output temperature and the collected value. Through parameter calibration, temperature drift calibration, aging calibration and other means, the measurement error caused by component parameter differences, temperature drift and long-term working aging is greatly reduced, and the measurement accuracy is improved. It has the advantages of simple implementation process and wide application range. In addition, while collecting high-precision temperature, it will not increase the complexity of the satellite-borne calibration source controller, thereby ensuring the accuracy of temperature measurement and the adaptability of the device to the working environment under long-life working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings constituting a part of this application are used to provide a further understanding of this application, so that other features, purposes and advantages of this application become more obvious. The schematic embodiment drawings and their descriptions of this application are used to explain this application and do not constitute an improper limitation on this application. In the drawings:

[0027] Figure 1 is a schematic diagram of a temperature measurement error calibration device for a radiometer thermal calibration source provided according to an embodiment of the present application;

[0028] Figure 2 is a functional schematic diagram of a temperature measurement channel switching module provided according to an embodiment of the present application;

[0029] Figure 3 It is a schematic diagram of the calibration process using a radiometer thermal calibration source temperature measurement error calibration device; DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0031] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0032] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0033] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0034] In addition, the term "plurality" shall mean two or more.

[0035] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0036] like Figure 1As shown, the present application provides a temperature measurement error calibration device for a radiometer thermal calibration source, comprising a platinum resistance temperature sensor, a constant current source module, a temperature measurement channel switching module, an ambient temperature acquisition module, an aging error calibration module, an amplification and filtering module, an AD conversion module and a microprocessor system module, wherein: a plurality of platinum resistance temperature sensors are provided, and the plurality of platinum resistance temperature sensors are all provided inside the radiation source, and each platinum resistance temperature sensor is electrically connected to the temperature measurement channel switching module; the constant current source module is electrically connected to the temperature measurement channel switching module for providing a constant current drive; the aging error calibration module, the ambient temperature acquisition module and the amplification and filtering module are all electrically connected to the temperature measurement channel switching module; the AD conversion module is electrically connected to the amplification and filtering module; and the microprocessor system module is electrically connected to the AD conversion module.

[0037] Specifically, the temperature measurement error calibration device for the thermal calibration source of the radiometer provided in the embodiment of the present application is mainly for on-orbit self-calibration of the temperature measurement error of the thermal calibration source of the satellite-borne microwave radiometer, and establishes a quantitative relationship between the input temperature and the output voltage. Through parameter calibration, temperature drift calibration, aging error calibration and other means, the measurement error caused by component parameter differences, component temperature drift and long-term working aging is greatly reduced, and the long-term accuracy of the measurement is improved; the overall calibration process includes three parts: temperature calibration, drift error and aging error calibration under different ambient temperatures, which can effectively improve the temperature measurement accuracy and long-term stability of the thermal calibration source device. The calibration fitting fixed residual is less than ±0.02K, and the temperature measurement accuracy is improved from 0.05K to 0.02K, which provides a basic guarantee for the microwave radiometer to provide a high-precision and high-stability standard radiation brightness temperature signal.

[0038] More specifically, in an embodiment of the present application, a plurality of platinum resistance temperature sensors are arranged inside the radiation source to provide multiple temperature measurement channels; a constant current source module is used to provide a common constant current drive for the multiple platinum resistance temperature sensors and the aging error calibration module; a temperature measurement channel switching module is used to switch the constant current source drive signal to the platinum resistance temperature sensors of different temperature measurement channels, so that the port voltage of the platinum resistance and the aging error calibration module is switched to the post-stage amplification and filtering circuit module for processing; an ambient temperature acquisition module is used to measure the ambient temperature of the internal circuit of the device as an ambient temperature parameter for on-track temperature drift error calibration; and an aging error calibration module is used as a standard for temperature measurement. The reference resistor is used to calibrate the errors caused by aging and performance degradation of the temperature measurement circuit components after long-term operation; the amplification and filtering module is used to condition and amplify the tiny voltage signal output by the platinum resistance temperature sensor, and perform low-pass filtering. By adjusting the amplification factor and offset, the voltage is adjusted to the AD acquisition range as much as possible to reduce the resolution of AD acquisition; the AD conversion module is used to convert the platinum resistance temperature measurement analog voltage signal after amplification and filtering into a digital temperature signal; the microprocessor system module is used for the collection and processing of temperature data, as well as the automatic execution of the temperature drift error and aging error calibration method, to achieve high-precision collection and calibration of the thermal calibration source temperature.

[0039] Further, such as Figure 2 As shown, a multi-channel high-voltage analog switch device is provided inside the temperature measurement channel switching module. The multi-channel high-voltage analog switch device is used, and its input port is in a high-impedance state when it is not powered on. The inconsistency of the characteristics between channels is small, and the error caused by the difference between the system acquisition channels is small. It is used for cold state switching of the temperature measurement channel of the platinum resistance temperature sensor.

[0040] Furthermore, the constant current provided by the constant current source module is less than 1mA. The constant current source module is used to provide a constant current drive for the platinum resistor and the aging calibration module. In order to reduce the self-heating of the current on the platinum resistor, the constant current source current is preferably less than 1mA, and has the characteristics of high reliability, high accuracy and high repeatability.

[0041] Furthermore, when the ambient temperature acquisition module acquires temperature, the deviation is less than ±1°C.

[0042] Furthermore, the drift value of the aging calibration module is smaller than the drift value of the platinum resistance temperature sensor itself. The aging calibration module is used to provide an aging reference value, and its drift value should be much smaller than the drift value of the platinum resistance temperature sensor itself, and the annual drift value is preferably less than 10ppm.

[0043] Furthermore, the main core device of the AD conversion module is a 16-bit AD976ASD. The main core device of the AD conversion module is preferably a 16-bit AD976ASD, which has high resolution, fast speed, small temperature drift and error.

[0044] In addition, if Figure 3 As shown, the embodiment of the present application also provides a method for calibrating a temperature measurement error using a radiometer thermal calibration source, which uses a combination of software and hardware to complete on-orbit self-calibration of temperature measurement errors and achieve long-term high-precision temperature measurement, specifically including the following steps:

[0045] Step 1: Determine the temperature measurement range, measurement accuracy and on-orbit working environment temperature of the device;

[0046] Determine the microwave radiation heat calibration source temperature measurement range T1~T2, temperature measurement accuracy ΔT and working environment temperature T E1 ~T E2 , the platinum resistance temperature sensor has completed metrological verification and has a graduation table;

[0047] Step 2: Place the device in a high-precision temperature test chamber, set the chamber temperature to 25°C, put the microprocessor system module in calibration mode, collect temperature data, and the collected value is the source code value output by the AD conversion module;

[0048] Step 3: Use a high-precision resistance box to simulate the graduation table of platinum resistance, set the resistance value at every 5K interval within the temperature measurement range, collect and record it through the microprocessor system module, and obtain the collected temperature, platinum resistance value, and collected hexadecimal source code value;

[0049] That is, within the temperature measurement range T1~T2, from the lower temperature limit to the upper temperature limit, the nominal resistance value is taken at the calibration temperature point interval of 5K, and is set on the standard DC multi-value resistance box respectively, and all the nominal resistance values ​​R are recorded. S , nominal temperature T S And the AD acquisition original source code value T output by the corresponding processor system module DATA ;

[0050] Step 4: Repeat the operation in step 3 for each channel. The collected data for each calibration temperature point shall be no less than 20, and the data collection and storage of all temperature measurement channels shall be completed.

[0051] Step 5: Fit the AD acquisition value collected by each temperature measurement channel with the corresponding nominal temperature value data by a cubic polynomial to calculate the calibration parameters of each channel;

[0052] That is, AD collects decimal data T DATA and the nominal temperature T in K S The data were imported into Origin data processing software and the quadratic curve function T was used as a variable. S =A×T DATA 3 +B×T DATA2 +C×T DATA +D is a mathematical model for fitting, and the calibration parameters A, B, C, and D of each temperature measurement channel are calculated;

[0053] Step 6: Bind the obtained calibration parameters of all temperature measurement channels into the microprocessor system module; within the temperature measurement range, use the nominal resistance value of the resistance box as input to collect temperature, and at an ambient temperature of 25°C, check whether the temperature measurement accuracy and range meet the requirements; if not, re-execute steps 3 to 6;

[0054] The mathematical model T S =A×T DATA 3 +B×T DATA 2 +C×T DATA +D and the calibration parameters A, B, C, D of each temperature measurement channel are bound into the embedded software of the microprocessor system module to complete the software calibration parameter binding; and different platinum resistance values ​​are input here to perform temperature testing to check whether the temperature measurement range and accuracy meet the error requirements. If not, repeat the above steps until the requirements are met;

[0055] Step 7: Adjust the temperature of the temperature test box, adjust the high and low temperature box to T1, stabilize the ambient temperature for 1 hour after equilibrium, perform temperature measurement accuracy test on all temperature measurement channels, and record the ambient temperature value fed back by the ambient temperature acquisition module, the temperature acquisition value of each channel, and the acquisition value of the aging error calibration module;

[0056] Step 8: Raise the temperature of the temperature test box by 5°C, and repeat the operation in step 7 until the temperature of the temperature test box reaches the upper limit of the device's operating temperature; sort out and record the ambient temperature value fed back by the ambient temperature acquisition module, the temperature acquisition values ​​of each channel, and the temperature value of the aging resistor sampling channel;

[0057] Step 9: Process the data, divide the temperature measurement range into three sections: upper, middle and lower, take the temperature error calibration values ​​respectively, and establish a quadratic polynomial between the ambient temperature and the temperature error calibration value, bind the temperature calibration mathematical model and parameters into the microprocessor system module, and complete the temperature drift error calibration;

[0058] The temperature measurement range is divided into T1~T x1 , T x1 ~T x2 , T x2 For the three regions T2 to T3, three error calibration values ​​△T are taken for each channel corresponding to different ambient temperature values, and compared with the measured ambient temperature value T HJ Perform quadratic fitting to obtain the quadratic polynomial of compensation value and ambient temperature value △T=E×T HJ 2+F×T HJ +G, obtain the three expected temperature compensation parameters E, F, G within the temperature measurement range; bind the temperature compensation parameters into the microprocessor system module to complete the temperature drift compensation calibration of temperature acquisition;

[0059] Step 10: By collecting the standard reference resistance in the aging error calibration module, the offset of the standard reference temperature is obtained to realize the aging error calibration of the temperature measurement data of the multi-channel platinum resistance temperature measurement sensor;

[0060] That is, the aging error calibration value ΔT is obtained by collecting the value Tc of the aging calibration module. LH =303-Tc, where the aging calibration benchmark is based on 303K; the aging error calibration parameters are bound to the processor system module to complete the aging error calibration of temperature acquisition;

[0061] Step 11: Set the temperature of the temperature test box to the upper, middle and lower ranges of the working environment temperature of the self-calibration device, use the standard resistance value of the resistance box as input to collect temperature, and check whether the temperature measurement range and accuracy meet the requirements. If not, repeat the above steps until the requirements are met.

[0062] Specifically, the device and method for calibrating the temperature measurement error of the radiometer thermal calibration source provided in the embodiments of the present application solve the problem of calibrating the on-orbit drift error of the satellite-borne microwave radiation thermal calibration source, and can effectively improve the measurement accuracy of the physical temperature of the blackbody of the thermal calibration source, reduce the temperature measurement error introduced by the on-orbit drift and the temperature non-uniformity of the blackbody radiation surface caused by the inconsistent errors between the temperature measurement channels, ensure the long-term stability of the temperature measurement accuracy and the accuracy of the brightness temperature standard signal, and realize the high-precision acquisition of the temperature of the satellite-borne microwave radiation thermal calibration source.

[0063] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A device for calibrating temperature measurement errors of a radiometer thermal calibration source, characterized in that: It includes a platinum resistance temperature sensor, a constant current source module, a temperature measurement channel switching module, an ambient temperature acquisition module, an aging error calibration module, an amplification and filtering module, an AD conversion module and a microprocessor system module, among which: A plurality of platinum resistance temperature measuring sensors are provided, and the plurality of platinum resistance temperature measuring sensors are all arranged inside the radiation source, and each of the platinum resistance temperature measuring sensors is electrically connected to the temperature measuring channel switching module; The constant current source module is electrically connected to the temperature measurement channel switching module, and is used to provide a constant current drive; The aging error calibration module, the ambient temperature acquisition module and the amplification and filtering module are all electrically connected to the temperature measurement channel switching module; The AD conversion module is electrically connected to the amplification and filtering module; The microprocessor system module is electrically connected to the AD conversion module.

2. The device for calibrating temperature measurement error of a radiometer thermal calibration source according to claim 1, characterized in that: The temperature measurement channel switching module is internally provided with a multi-channel high-voltage analog switch device.

3. The device for calibrating temperature measurement error of a radiometer thermal calibration source according to claim 2, characterized in that: The constant current provided by the constant current source module is less than 1 mA.

4. The device for calibrating temperature measurement error of a radiometer thermal calibration source according to claim 3, characterized in that: When the ambient temperature acquisition module performs temperature acquisition, the deviation is less than ±1°C.

5. The device for calibrating temperature measurement error of a radiometer thermal calibration source according to claim 4, characterized in that: The drift value of the aging calibration module is smaller than the drift value of the platinum resistance temperature sensor itself.

6. The device for calibrating temperature measurement error of a radiometer thermal calibration source according to claim 5, characterized in that: The main core device of the AD conversion module is the 16-bit AD976ASD.

7. A method for calibrating temperature measurement errors of a radiometer thermal calibration source using the device of claim 6, characterized in that: The steps include: Step 1: Determine the temperature measurement range, measurement accuracy and on-orbit working environment temperature of the device; Step 2: Place the device in a high-precision temperature test chamber, set the chamber temperature to 25°C, put the microprocessor system module in calibration mode, collect temperature data, and the collected value is the source code value output by the AD conversion module; Step 3: Use a high-precision resistance box to simulate the graduation table of platinum resistance, set the resistance value at every 5K interval within the temperature measurement range, collect and record it through the microprocessor system module, and obtain the collected temperature, platinum resistance value, and collected hexadecimal source code value; Step 4: Repeat the operation in step 3 for each channel to complete the data collection and storage of all temperature measurement channels; Step 5: Fit the AD acquisition value collected by each temperature measurement channel with the corresponding nominal temperature value data by a cubic polynomial to calculate the calibration parameters of each channel; Step 6: Bind the obtained calibration parameters of all temperature measurement channels into the microprocessor system module; within the temperature measurement range, use the nominal resistance value of the resistance box as input to collect temperature, and at an ambient temperature of 25°C, check whether the temperature measurement accuracy and range meet the requirements; if not, re-execute steps 3 to 6; Step 7: Adjust the temperature of the temperature test box, starting with the lower limit of the actual working environment temperature. After the environment temperature is balanced and stabilized for 1 hour, perform temperature measurement accuracy tests on all temperature measurement channels according to step 6, and record the environment temperature value fed back by the environment temperature acquisition module, the temperature acquisition values ​​of each channel, and the acquisition values ​​of the aging error calibration module; Step 8: Raise the temperature of the temperature test chamber by 5°C, and repeat the operation in step 7 until the temperature of the temperature test chamber reaches the upper limit of the device operating temperature; Step 9: Process the data, divide the temperature measurement range into three sections: upper, middle and lower, take the temperature error calibration values ​​respectively, and establish a quadratic polynomial between the ambient temperature and the temperature error calibration value, bind the temperature calibration mathematical model and parameters into the microprocessor system module, and complete the temperature drift error calibration; Step 10: By collecting the standard reference resistance in the aging error calibration module, the offset of the standard reference temperature is obtained to realize the aging error calibration of the temperature measurement data of the multi-channel platinum resistance temperature measurement sensor; Step 11: Set the temperature of the temperature test box to the upper, middle and lower ranges of the working environment temperature of the self-calibration device, use the standard resistance value of the resistance box as input to collect temperature, and check whether the temperature measurement range and accuracy meet the requirements. If not, repeat the above steps until the requirements are met.

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