On-orbit medium-long wave infrared radiation calibration method based on multiple measurement data of satellite-borne black body

Abstract

The invention provides an in-orbit medium-long wave infrared radiation calibration method based on multiple measurement data of a satellite-borne black body. The method comprises the steps that the heating temperature of the satellite-borne black body and imaging data output by a load in the ith calibration task are acquired; determining a mean value of imaging data of each detector of the load and a mean value of all imaging data of all detectors; establishing a relative radiation correction linear equation by using the mean value of the imaging data of each detector and the mean value of all the imaging data of all the detectors, and determining a relative radiation correction coefficient after completing at least two calibration tasks; determining spectral radiance according to the heating temperature of the blackbody on the satellite; and establishing an absolute radiation correction linear equation by using the spectral radiance and a mean value of all imaging data of all detectors, and determining an absolute radiation correction coefficient after completing at least two calibration tasks. The multi-point method is adopted to improve the calibration precision of the blackbody on the satellite, the calculation amount and the storage resource occupation amount are reduced, and the processing calculation efficiency on the satellite is improved.

Description

Technical Field

[0001] This invention belongs to the field of on-board data processing technology, and specifically relates to an on-orbit medium- and long-wave infrared radiometric calibration method based on multiple measurements of onboard blackbody data. It is applicable to medium- and long-wave infrared remote sensing satellites in orbit, enabling rapid on-orbit quantitative processing of infrared data, as well as downlinking and distribution, to meet the timeliness requirements of satellite users for satellite imagery. Background Technology

[0002] In the field of quantitative infrared remote sensing, radiometric correction needs to be performed in orbit. The prerequisite for radiometric correction is obtaining the corresponding correction coefficients, i.e., infrared radiometric calibration. In traditional ground-based systems, calibration parameters require multiple steps, including remote sensing data downlink, ground processing, and calibration parameter uplink, before the satellite can acquire the relevant parameters, which is time-consuming. In some high-time-efficiency application scenarios, this is insufficient to meet the requirements of satellite users. Therefore, satellite operators need to establish the capability to rapidly acquire calibration parameters in orbit.

[0003] Generally, there are two methods for infrared radiometric calibration. One method involves using data collected from the calibration field and the satellite payload data when the remote sensing satellite passes over the ground to obtain calibration parameters. The other method uses an onboard blackbody, obtaining calibration parameters by combining blackbody brightness temperature data collected by the remote sensing satellite in orbit with payload data. During blackbody calibration, the blackbody temperature is kept constant, and a high-sensitivity thermocouple continuously outputs blackbody brightness temperature data. At this time, the mid-to-long-wave infrared glow generated by the blackbody radiation illuminates the payload's detector, which outputs DN (remote sensing image pixel brightness value) data. Typically, satellites using blackbodies also carry ground-based blackbody emissivity data for data processing. Due to limitations in on-orbit conditions, remote sensing satellites typically use the onboard blackbody method to achieve mid-to-long-wave infrared radiometric calibration while in orbit.

[0004] On-board blackbody calibration for mid- and long-wave infrared radiation typically employs three methods: the two-point method, the histogram method (including matching and equalization methods), and the classification and statistical method. Due to limitations in satellite resources, remote sensing satellites mostly use the two-point method for on-orbit infrared calibration.

[0005] The two-point method first assumes a linear relationship between the DN value of the infrared camera and physical characteristic parameters such as spectral radiance. This relationship can be described using a linear function model, meaning the model can be determined using only two parameters: slope and intercept. Therefore, by providing the blackbody temperature values ​​at two points and the corresponding physical quantity values, two linear equations can be constructed, allowing the calculation of the slope and intercept parameters and the determination of the linear function model. However, in orbit, the two-point method is subject to certain errors due to factors such as the uncertainty of the blackbody radiation source, the blackbody emissivity, and the stability error of the camera output signal. Summary of the Invention

[0006] To overcome the shortcomings of existing technologies, the inventors have conducted intensive research and provided an on-orbit mid-wave infrared radiation calibration method based on multiple measurement data of a spaceborne blackbody. This method uses a multi-point approach to improve the accuracy of on-board blackbody calibration, reduce computational load and storage resource consumption, improve on-board processing efficiency, and is compatible with typical on-board processing hardware, thus completing this invention.

[0007] The technical solution provided by this invention is as follows: Firstly, an on-orbit mid-to-long-wave infrared radiation calibration method based on multiple measurements from a spaceborne blackbody includes: Get the i The onboard blackbody heating temperature during the second calibration mission. i ≥1; Get the i The imaging data output by the payload in the calibration mission is the imaging data after the heated on-board blackbody is placed in the payload optical path and the payload outputs the image stably. According to the i The imaging data output by the payload in the calibration mission is used to determine the mean value of the imaging data of each detector on the payload and the mean value of all imaging data of all detectors. By using the mean of imaging data from each detector and the mean of all imaging data from all detectors, a linear equation for relative radiometric correction is established. After completing at least two calibration tasks, the relative radiometric correction coefficient is determined. The spectral radiance is determined based on the heating temperature of the blackbody on the satellite. By using the spectral radiance and the mean of all imaging data from all detectors, an absolute radiometric correction linear equation is established, and the absolute radiometric correction coefficient is determined after at least two calibration tasks are completed.

[0008] Secondly, an on-orbit mid-to-long-wave infrared radiation calibration device based on multiple measurements of a spaceborne blackbody includes: One or more processors; Storage device for storing one or more programs. When the one or more programs are executed by the one or more processors, the one or more processors implement the on-orbit long-wave infrared radiometric calibration method based on multiple measurements of a spaceborne blackbody as described in the first aspect.

[0009] Thirdly, a readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the on-orbit mid-wave infrared radiometric calibration method based on multiple measurements of a spaceborne blackbody as described in the first aspect.

[0010] Fourthly, a computer program product comprising: a computer program (also referred to as code or instructions) that, when executed, performs the on-orbit long-wave infrared radiometric calibration method based on multiple measurements of a spaceborne blackbody as described in the first aspect.

[0011] The on-orbit mid-to-long-wave infrared radiation calibration method based on multiple measurements of a spaceborne blackbody provided by the present invention has the following beneficial effects: (1) The present invention provides an on-orbit medium-wave infrared radiation calibration method based on multiple measurement data of a spaceborne blackbody. The multiple blackbody calibration method is introduced. Compared with the traditional two-point method, the multi-point method has more blackbody temperature points. The calibration coefficients obtained by using more temperature points can improve the accuracy of subsequent processing. (2) The present invention provides an on-orbit mid-wave infrared radiation calibration method based on multiple measurement data of a spaceborne blackbody, which reduces buffering. m In the case of secondary mission data, storage resources are allocated to accommodate the limited computing resources available for satellites in orbit. If each radiation correction involves... s Yes, traditional methods require storage ( i +1) All data from this correction task will be used. n × s ×( i +1) Storage capacity: Using the method of this invention, only 3 n +4 data points, among which , , Each detector needs to store data, requiring 3... n indivual. , , , Four are needed for all detectors to share. Compared to the conventional method, the calculation results are consistent with those of the method of this invention, but the storage capacity requirement of the method of this invention is reduced.

[0012] (3) The present invention provides an on-orbit long-wave infrared radiation calibration method based on multiple measurement data of a spaceborne blackbody, which changes the number of rows of imaging data to a power of 2. When determining the average value of imaging data of each detector, this method can significantly speed up the calculation speed and reduce division operations when implemented on FPGA. (4) The present invention provides an on-orbit long-wave infrared radiation calibration method based on multiple measurements of a spaceborne blackbody. According to the blackbody temperature range and temperature measurement accuracy, a blackbody temperature and spectral radiance lookup table is generated. When determining the spectral radiance using the blackbody heating temperature, the lookup table method is used, which can significantly reduce exponential and reciprocal calculations and improve the computational efficiency and adaptability of the algorithm of the present invention in FPGA hardware.

[0013] (5) The present invention provides an on-orbit long-wave infrared radiation calibration method based on multiple measurement data of a spaceborne blackbody, which improves the efficiency of performing blackbody calibration tasks on orbit by using a multi-blackbody and mechanism switching mechanism. Attached Figure Description

[0014] Figure 1 This is a flowchart of the on-orbit long-wave infrared radiation calibration method based on multiple measurements of a spaceborne blackbody according to the present invention. Detailed Implementation

[0015] The features and advantages of the present invention will become clearer and more explicit from the following detailed description.

[0016] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0017] This invention provides an on-orbit mid-to-long-wave infrared radiation calibration method based on multiple measurements of a spaceborne blackbody, such as... Figure 1 As shown, it includes the following steps: Step 1: Activate the onboard blackbody heating function and monitor the blackbody temperature using a thermistor until the set temperature is reached. T i , i Indicates execution of the first i Secondary blackbody calibration task.

[0018] In this step, multiple temperature settings for the blackbody are set to conduct radiometric calibration at as many different blackbody temperatures as possible.

[0019] Step 2: The satellite uses its onboard structure and mechanisms to place the heated blackbody into the payload optical path, activates the payload imaging function, and outputs imaging data.

[0020] Step 3: Wait for the set time t 0. After the payload output stabilizes, the satellite service subsystem sends commands to drive the onboard processing subsystem, controlling the onboard processing subsystem to receive payload imaging data and transmit the set temperature. T i To the on-board processing subsystem.

[0021] Step 4: The onboard processing subsystem receives imaging data and temperature data, receiving a total of imaging data. s Each row contains imaging data detected by all detectors on the payload in a single operation. s The entire payload includes all detectors. sThe onboard processing subsystem calculates the average value of each detector pixel (imaging data) and the average value of all pixels across all detectors. Assume the current value is the [number missing]. i The second blackbody calibration task involves calculating the mean value to obtain the first... n The average value of the detector pixels, denoted as . The average value of all imaging data for this blackbody correction is denoted as . In principle, the two means have the following relationship: (1) In the formula, N This represents the total number of detector pixels.

[0022] In this step, the number of rows of imaging data for each time is... s Set it to a multiple of 2, or select the number of rows in the bold calibration data that are powers of 2 for processing, and convert all floating-point numbers that may be generated in the intermediate process to fixed-point.

[0023] Step 5: The on-board processing subsystem calculates the relative radiation correction factor.

[0024] The on-orbit calibration method of this invention is a multi-point method, which establishes a relative radiation correction equation, that is, assuming that for and The following approximate relationship exists: (2) In the formula, k n and b n This represents the corresponding relative radiometric correction coefficient. According to the least squares principle, if a total of... m For the next calibration task, if m ≥ 2, then the relative radiation correction coefficient... k n and b n It can be obtained using the following formula: (3) exist m When =1, each sum contains only one term, that is, the sum only contains the following table. i The terms with a value of 1 k n Of the two terms in the denominator on the right, for , for If the two values ​​are equal, meaning the denominator is 0, then the operation cannot be performed. k n , b n Calculation. Therefore, in mWhen =1, this step needs to be skipped. k n , b n The calculation process.

[0025] exist m When =2, for , for At this point, if all terms are equal, that is... Since the two values ​​are still equal, the denominator is 0, and the function cannot be executed. k n , b n The calculation can be extrapolated similarly to... m The case of ≥2. Therefore, when m When ≥2, it is necessary to avoid all terms being equal. The corresponding practical meaning is that, but it is completed multiple times ( m ≥2) When performing blackbody calibration, it is necessary to ensure that the blackbody temperature value is not unique for each observation, and to avoid performing blackbody calibration multiple times at a single temperature measurement point.

[0026] In this step, intermediate variables can be cached to reduce computation. For example, the current step has just completed the first... m The calculation of the relative radiation correction factor is performed using the formula. k n , b n The following four intermediate process variables in the right-hand side of the formula can be cached: , , ,

[0027] In the next round, that is, the first... m For +1 relative radiation correction, simply... , , , By adding the corresponding sums from the four above, we can obtain the result. m +1 calibration task k n , b n Calculate the values ​​of all sums on the right side of the formula.

[0028] Specifically, during the first scaling task calculation, the above sum is calculated and cached, but the calculated sum is not used for calculation. k n and b n .

[0029] Step Six: The onboard processing subsystem converts the blackbody temperature transmitted by the satellite's operational subsystem into spectral radiance. Establishing a correlation between blackbody temperature and physical quantities is a necessary step in absolute radiometric calibration. This paper selects spectral radiance as the physical quantity after absolute radiometric correction. Typically, the satellite provides temperature data and pre-stored emissivity data in orbit. The emissivity data is obtained through calibration in a ground laboratory and then stored on the satellite. Using Planck's formula and the emissivity data, the spectral radiance information acquired by the infrared detector is obtained.

[0030] (4) In the formula, L Spectral radiance, in W. m -2 sr -1 μm -1 ; h It is Planck's constant; λ It is the center wavelength of the mid-to-long-wave infrared spectrum; c It is the speed of light in a vacuum; k B For Boltzmann; T i For the first i The blackbody temperature during the calibration task is expressed in Kelvin (K). ε Emissivity. The values ​​and units of each constant parameter are shown in Table 1 below: Table 1

[0031] In this step, a blackbody temperature and spectral radiance lookup table is generated according to the blackbody temperature range and temperature measurement accuracy. When calculating Planck's formula, the spectral radiance at the current blackbody temperature can be quickly obtained using the lookup table.

[0032] Step 7: The onboard processing subsystem calculates the absolute radiometric correction coefficients. The linear equation for absolute radiometric correction is established, namely: (5) In the formula, G, B For absolute radiometric calibration coefficients. According to the least squares principle, if a total of [missing information] is completed... m The next calibration task, then the coefficient G and B It can be obtained using the following formula: (6) In this step, intermediate variables can be cached to reduce computation. For example, the current step has just completed the first... m Sub-absolute radiometric correction calculation, using the formula G , BThe following four intermediate process variables in the right-hand side of the formula can be cached: , , ,

[0033] In the next round, that is, the first... m For +1 absolute radiation correction, simply... , , , By adding the corresponding sums from the four above, we can obtain the result. m +1 calibration task G , B Calculate the values ​​of all sums on the right side of the formula.

[0034] When calculating relative and absolute radiation correction factors... As a shared variable, it can be stored only once and shared when processed by relative and absolute radiation correction coefficients.

[0035] Step 8: The on-board processing subsystem will process the calculated coefficients. k n , b n , G, B Storage, for use in subsequent processing.

[0036] Step Nine: The satellite's operational subsystem determines whether all calibration tasks have been completed; if not, the blackbody temperature is reset. Steps One through Eight are repeated. The calibration coefficients are continuously corrected using multiple onboard blackbody measurement data. k n , b n , G, B .

[0037] In this step, the number of blackbodies is increased, and each blackbody is set to a different temperature. During the calibration of the current blackbody, the heating of the remaining blackbodies is completed in advance; after the calibration of the current blackbody is completed, a mechanism is used to switch the satellite blackbody.

[0038] The following example illustrates the on-orbit mid-wave infrared radiation calibration method based on multiple measurements of a spaceborne blackbody.

[0039] Execution steps are as follows Figure 1 As shown.

[0040] The data has the following form: (1) The data content of each row is consistent in each calibration task.

[0041] (2) For the first calibration task, the blackbody temperature is 300.54K, the value of the first 6000 pixels is 1.25, and the value of the last 2000 pixels is 0.25.

[0042] (3) Second calibration task, blackbody temperature 356.23K, the value of the first 6000 pixels is 2.5, and the value of the last 2000 pixels is 0.5.

[0043] (4) The third calibration task, the blackbody temperature is 398.91K, the value of the first 6000 pixels is 3.75, and the value of the last 2000 pixels is 0.75.

[0044] (5) The above data m =3, the blackbody temperature has 3 different values, which satisfies... m ≥2. The requirement that the blackbody temperature value is not unique.

[0045] The data used is shown in Table 2, and the symbols used are the same as those above.

[0046] Table 2

[0047] In this embodiment, three blackbody calibration tasks will be carried out.

[0048] First blackbody calibration task: Step 1.1: Heat the blackbody to 300.54K.

[0049] Step 2.1: The blackbody enters the payload optical path, and the payload begins imaging.

[0050] Step 3.1: After waiting 10 seconds, the payload output stabilizes. The satellite service subsystem sends a command to drive the on-board processing subsystem, which in turn controls the on-board processing subsystem to receive the payload imaging data and transmit the set temperature of 300.54K to the on-board processing subsystem.

[0051] Step 4.1: Calculate the time mean With the average value of all pixels The calculation results are shown in Table 3.

[0052] Step 5.1: Since this is the first calculation, no further steps are needed. k n , b n calculate.

[0053] The relative radiation correction coefficient is calculated according to formula (3). k n , b n The calculation results are shown in Table 4.

[0054] Step 6.1: Convert the blackbody temperature into spectral radiance. According to formula (4), the spectral radiance at the third blackbody temperature can be calculated. L As shown in Table 5.

[0055] Step 7.1: Since this is the first calculation, no further steps are needed. G , B calculate.

[0056] Calculate the absolute radiometric calibration coefficients. According to formula (5), the absolute radiometric calibration coefficients can be calculated. G , B As shown in Table 6.

[0057] Step 8.1: Store intermediate variables. The results of the intermediate variables after this calculation are shown in Tables 4 and 6.

[0058] Step 9.1: If not all tasks are completed, begin the second calibration task.

[0059] Second blackbody calibration task: Step 1.2: Heat the blackbody to 356.23K.

[0060] Step 2.2: The blackbody enters the payload optical path, and the payload begins imaging.

[0061] Step 3.2: After waiting 10 seconds, the payload output stabilizes. The satellite service subsystem sends a command to drive the on-board processing subsystem, which in turn controls the on-board processing subsystem to receive the payload imaging data and transmits the set temperature of 356.23K to the on-board processing subsystem.

[0062] Step 4.2: Calculate the time mean With the average value of all pixels The calculation results are shown in Table 3.

[0063] Step 5.2: Calculate the relative radiation correction coefficient according to formula (3). k n , b n The calculation results are shown in Table 4.

[0064] Step 6.2: Convert the blackbody temperature into spectral radiance. According to formula (4), the spectral radiance at the third blackbody temperature can be calculated. L As shown in Table 5.

[0065] Step 7.2: Calculate the absolute radiometric calibration coefficients. The absolute radiometric calibration coefficients can be calculated using formula (5). G , B As shown in Table 6.

[0066] Step 8.2: Store the correction coefficients kn , b n , G, B The intermediate variables are stored, and the correction coefficients and intermediate variable results after this calculation are shown in Tables 4 and 6.

[0067] Step 9.2: If not all tasks are completed, begin the third calibration task.

[0068] Third blackbody calibration task: Step 1.3: Heat the blackbody to 398.91K.

[0069] Step 2.3: The blackbody enters the payload optical path, and the payload begins imaging.

[0070] Step 3.3: After waiting 10 seconds, the payload output stabilizes. The satellite service subsystem sends a command to drive the on-board processing subsystem, which in turn controls the on-board processing subsystem to receive the payload imaging data and transmit the set temperature of 398.91K to the on-board processing subsystem.

[0071] Step 4.3: Calculate the time mean With the average value of all pixels The calculation results are shown in Table 3.

[0072] Step 5.3: Calculate the relative radiation correction coefficient according to formula (3). k n , b n The calculation results are shown in Table 4.

[0073] Step 6.3: Convert the blackbody temperature into spectral radiance. According to formula (4), the spectral radiance at the third blackbody temperature can be calculated. L As shown in Table 5.

[0074] Step 7.3: Calculate the absolute radiometric calibration coefficients. The absolute radiometric calibration coefficients can be calculated using formula (5). G , B As shown in Table 6.

[0075] Step 8.3: Store the correction coefficients k n , b n , G, B The intermediate variables are stored, and the correction coefficients and intermediate variable results after this calculation are shown in Tables 4 and 6.

[0076] Step 9.3: Complete all tasks and the calibration process is complete.

[0077] Table 3

[0078] Table 4

[0079] Table 5

[0080] Table 6

[0081] This invention also provides an on-orbit mid-to-long-wave infrared radiometric calibration device based on multiple measurements of a spaceborne blackbody, integrating a satellite service subsystem and an on-board processing subsystem, comprising: One or more processors; Storage device for storing one or more programs. When the one or more programs are executed by the one or more processors, the one or more processors implement the on-orbit long-wave infrared radiometric calibration method based on multiple measurements of a spaceborne blackbody as described above.

[0082] The present invention also provides a readable storage medium storing a computer program that, when executed by a processor, implements the on-orbit long-wave infrared radiation calibration method based on multiple measurements of a spaceborne blackbody as described above.

[0083] The readable storage media include, but are not limited to, USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, optical disks, and other media capable of storing program code.

[0084] The present invention also provides a computer program product, the computer program product comprising: a computer program (also referred to as code or instructions), which, when the computer program is run, executes the on-orbit long-wave infrared radiometric calibration method based on multiple measurement data of a spaceborne blackbody as described above.

[0085] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, microwave, etc.) means.

[0086] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0087] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the devices, apparatuses, and modules described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0088] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

[0089] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. An on-orbit mid-to-long-wave infrared radiation calibration method based on multiple measurements from a spaceborne blackbody, characterized in that, include: Get the i The onboard blackbody heating temperature during the second calibration mission. i ≥1; Get the i The imaging data output by the payload in the calibration mission is the imaging data after the heated on-board blackbody is placed in the payload optical path and the payload outputs the image stably. According to the i The imaging data output by the payload in the calibration mission is used to determine the mean value of the imaging data of each detector on the payload and the mean value of all imaging data of all detectors. By using the mean of imaging data from each detector and the mean of all imaging data from all detectors, a linear equation for relative radiometric correction is established. After completing at least two calibration tasks, the relative radiometric correction coefficient is determined. The spectral radiance is determined based on the heating temperature of the blackbody on the satellite. By using the spectral radiance and the mean of all imaging data from all detectors, an absolute radiometric correction linear equation is established, and the absolute radiometric correction coefficient is determined after at least two calibration tasks are completed.

2. The on-orbit mid-wave infrared radiation calibration method based on multiple measurements of a spaceborne blackbody according to claim 1, characterized in that, The acquisition of the first i In the step of outputting imaging data from the payload during the secondary calibration task, the imaging data is... s Each row contains imaging data detected by all detectors on the payload in a single operation. s The entire payload includes all detectors. s The first detected imaging data.

3. The on-orbit mid-wave infrared radiation calibration method based on multiple measurements of a spaceborne blackbody according to claim 2, characterized in that, The acquisition of the first i In the step of outputting imaging data from the payload in this calibration task, the number of rows of imaging data for each step is... s Set it to a multiple of 2, or select the number of rows in the middle of the imaging data that are powers of 2 for processing, and convert all floating-point numbers generated in the intermediate process to fixed-point.

4. The on-orbit mid-wave infrared radiation calibration method based on multiple measurements of a spaceborne blackbody according to claim 1, characterized in that, In the step of establishing the relative radiation correction linear equation and determining the relative radiation correction coefficients after completing at least two calibration tasks, the relative radiation correction linear equation is as follows: In the formula, For the first i The mean of all imaging data from all detectors under this calibration mission. For the first i The mean value of imaging data from each detector during this calibration mission. k n and b n This is the corresponding relative radiation correction factor; After completing at least two calibration tasks, the relative radiation correction factor k n and b n Determine using the following formula: 。 In the formula, m This represents the total number of calibration tasks, indicating the number of tasks currently completed. m This is the next calibration task.

5. The on-orbit mid-wave infrared radiation calibration method based on multiple measurements of a spaceborne blackbody according to claim 4, characterized in that, The step of establishing the relative radiation correction linear equation and determining the relative radiation correction coefficients after completing at least two calibration tasks further includes: After completing the first m When calculating the relative radiation correction coefficient, the following four intermediate process variables are cached: , , , ; In the m For +1 relative radiation correction, simply... , , , and , , , Add the corresponding values ​​together to get the result. m The numerical values ​​of all sums on the right-hand side of the linear equation for relative radiation correction under +1 calibration mission.

6. The on-orbit mid-wave infrared radiation calibration method based on multiple measurements of a spaceborne blackbody according to claim 1, characterized in that, In the step of determining the spectral radiance based on the heating temperature of the on-board blackbody, the spectral radiance is determined by the following formula: In the formula, L Spectral radiance, in W. m -2 sr -1 μm -1 ; h It is Planck's constant; λ It is the center wavelength of the mid-to-long-wave infrared spectrum; c It is the speed of light in a vacuum; k B For Boltzmann; T i For the first i The blackbody temperature during the calibration task is expressed in Kelvin (K). ε Emission rate.

7. The on-orbit mid-wave infrared radiation calibration method based on multiple measurements of a spaceborne blackbody according to claim 1, characterized in that, In the step of establishing the absolute radiation correction linear equation and determining the absolute radiation correction coefficients after completing at least two calibration tasks, the absolute radiation correction linear equation is as follows: In the formula, For the first i The mean of all imaging data from all detectors under this calibration mission. L i For the first i Spectral radiance under this calibration task G, B The absolute radiation calibration coefficient; After completing at least two calibration tasks, the absolute radiation correction coefficient G and B Determine using the following formula: In the formula, m This represents the total number of calibration tasks, indicating the number of tasks currently completed. m This is the next calibration task.

8. The on-orbit mid-wave infrared radiation calibration method based on multiple measurements of a spaceborne blackbody according to claim 7, characterized in that, The step of establishing the absolute radiation correction linear equation and determining the absolute radiation correction coefficients after completing at least two calibration tasks further includes: After completing the first m During sub-absolute radiometric correction, the following four intermediate process variables are cached: , , , ; In the m For +1 absolute radiation correction, simply... , , , and , , , Add the corresponding values ​​together to get the result. m Numerical values ​​of all summations on the right-hand side of the linear equation for absolute radiometric correction under +1 calibration mission; The shared variable used to determine the relative and absolute radiometric correction coefficients is stored only once and is shared when processing the relative and absolute radiometric correction coefficients.

9. The on-orbit mid-wave infrared radiation calibration method based on multiple measurements of a spaceborne blackbody according to claim 4 or 7, characterized in that, The acquisition of the first i The on-board blackbody heating temperature varies in each calibration mission.

10. A computer program product, characterized in that, The computer program product includes: a computer program that, when the computer program is run, executes the on-orbit mid-wave infrared radiation calibration method based on multiple measurement data of a spaceborne blackbody as described in any one of claims 1 to 9.

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