A brightness temperature correction method, device, equipment and medium

Abstract

This invention discloses a brightness temperature correction method, apparatus, device, and medium, relating to the field of satellite applications. The brightness temperature correction method includes: obtaining a first equivalent brightness temperature of the satellite antenna when the satellite is at a first azimuth angle based on the physical temperature of the satellite antenna; determining a second equivalent brightness temperature of the satellite body when the satellite is at the first azimuth angle based on the first equivalent brightness temperature, and the simulated brightness temperature and observed brightness temperature of the satellite at the first azimuth angle; and correcting the observed brightness temperature by using the sum of the first equivalent brightness temperature and the second equivalent brightness temperature as the brightness temperature observation deviation of the satellite at the first azimuth angle. This method considers the influence of the first equivalent brightness temperature caused by the physical temperature of the satellite antenna and the second equivalent brightness temperature of the satellite body on the observed brightness temperature during the brightness temperature correction process, thereby improving the accuracy of the observed brightness temperature correction.

Description

Technical Field

[0001] This invention relates to the field of satellite applications, and in particular to a brightness temperature correction method, apparatus, equipment, and medium. Background Technology

[0002] A spaceborne scanning microwave radiometer is a precision brightness temperature measurement device. This device uses a rotating mechanism to drive the antenna-receiver system to perform a conical scan, thereby observing the brightness temperature data of the ground. However, the observed brightness temperature varies at different scanning positions, which is a characteristic of scanning microwave radiometers. The brightness temperature deviation obtained by this observation method is usually large, so it needs to be corrected. Summary of the Invention

[0003] The purpose of this invention is to provide a brightness temperature correction method for correcting the observed brightness temperature of satellites.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] This invention first provides a brightness temperature correction method, comprising:

[0006] Based on the physical temperature of the satellite antenna, the first equivalent brightness temperature of the satellite antenna when the satellite is at the first azimuth angle is obtained;

[0007] Based on the first equivalent brightness temperature, and the simulated brightness temperature and observed brightness temperature of the satellite when it is at the first azimuth angle, determine the second equivalent brightness temperature of the satellite body when it is at the first azimuth angle;

[0008] The sum of the first equivalent brightness temperature and the second equivalent brightness temperature is used as the brightness temperature observation deviation of the satellite at the first azimuth angle, and the observed brightness temperature is corrected accordingly.

[0009] In one optional embodiment of this application, obtaining the first equivalent brightness temperature of the satellite antenna when the satellite is at a first azimuth angle based on the physical temperature of the satellite antenna includes:

[0010] Obtain the physical temperature and emissivity of the satellite antenna;

[0011] The first equivalent brightness temperature is obtained by weighted summation of the product of the physical temperature of the satellite antenna and the emissivity of the antenna.

[0012] In one optional embodiment of this application, it further includes:

[0013] When the azimuth angle of the satellite is zero, the sample observation brightness temperature and the sample simulated brightness temperature of the satellite are obtained.

[0014] The third equivalent brightness temperature of the satellite antenna is determined based on the observed brightness temperature and the simulated brightness temperature of the sample.

[0015] The emissivity of the antenna and the temperature weights of each platinum resistor of the satellite antenna are determined based on the latitude of the satellite's ascending and descending orbit intersection point, the physical temperature of the satellite antenna, and the third equivalent brightness temperature; wherein, the platinum resistors of the satellite antenna are used to measure the physical temperature of the satellite antenna.

[0016] In one optional embodiment of this application, the first equivalent brightness temperature is obtained by the following formula:

[0017] ;

[0018] in, This represents the first equivalent brightness temperature; j represents the j-th platinum resistance thermometer in the satellite antenna; This represents the physical temperature of the satellite antenna as measured by the j-th platinum resistance thermometer in the satellite antenna. This represents the temperature weight of the j-th platinum resistance thermometer; represents the antenna emissivity; f represents the microwave frequency.

[0019] In one optional embodiment of this application, the antenna emissivity and the temperature weight are obtained by the following formula:

[0020] ;

[0021] ;

[0022] ;

[0023] ;

[0024] in, This is a correction factor for the antenna emissivity; The conductivity of the reflective surface; Indicates the latitude of the satellite; , , , , The polynomial coefficients of the correction factor are represented. This represents the distance between the j-th platinum resistance thermometer and the focal point of the satellite antenna; c is the antenna focal point; and Represents the coordinates of the j-th platinum resistance thermometer; , , , , The polynomial coefficients represent the temperature weights.

[0025] In one optional embodiment of this application, determining the second equivalent brightness temperature of the satellite body when the satellite is at the first azimuth angle, based on the first equivalent brightness temperature and the simulated brightness temperature and observed brightness temperature of the satellite at the first azimuth angle, includes:

[0026] When the satellite is determined to be at the first azimuth angle, the observed brightness temperature and simulated brightness temperature of the satellite in different physical temperatures and different latitude ranges;

[0027] Based on the difference between the observed brightness temperature and the simulated brightness temperature, and the first equivalent brightness temperature, the fourth equivalent brightness temperature of the satellite body in different physical temperatures and different latitude ranges is determined;

[0028] The average value of the fourth equivalent brightness temperature is used as the second equivalent brightness temperature.

[0029] In one optional embodiment of this application, the fourth equivalent brightness temperature is obtained by the following formula:

[0030] ;

[0031] in, The value represents the difference between the observed brightness temperature and the simulated brightness temperature; f represents the microwave frequency; This indicates the azimuth angle of the satellite; This indicates the first equivalent brightness temperature; This refers to the fourth equivalent brightness temperature.

[0032] Compared with existing technologies, the brightness temperature correction method provided by this invention considers the first equivalent brightness temperature of the satellite antenna and the second equivalent brightness temperature of the satellite body when the satellite is at different azimuth angles during the correction of the observed brightness temperature. The method combines the first equivalent brightness temperature and the second equivalent brightness temperature to correct the observed brightness temperature of the satellite. In the process of brightness temperature correction, this method considers the influence of the first equivalent brightness temperature caused by the physical temperature of the satellite antenna and the second equivalent brightness temperature of the satellite body on the observed brightness temperature, thereby improving the correction accuracy of the observed brightness temperature.

[0033] The present invention also provides a brightness temperature correction device, comprising:

[0034] The first unit is used to obtain the first equivalent brightness temperature of the satellite antenna when the satellite is at the first azimuth angle, based on the physical temperature of the satellite antenna.

[0035] The second unit is used to determine the second equivalent brightness temperature of the satellite body when the satellite is in the first azimuth angle based on the first equivalent brightness temperature and the simulated brightness temperature and observed brightness temperature when the satellite is in the first azimuth angle.

[0036] The third unit is used to correct the observed brightness temperature by taking the sum of the first equivalent brightness temperature and the second equivalent brightness temperature as the brightness temperature observation deviation of the satellite at the first azimuth angle.

[0037] Compared with the prior art, the beneficial effects of the brightness temperature correction device provided by the present invention are the same as those of the brightness temperature correction method described in the above technical solutions, and will not be repeated here.

[0038] The present invention also provides an electronic device, comprising:

[0039] processor;

[0040] Memory used to store the processor's executable instructions;

[0041] The processor is configured to execute the brightness temperature correction method described above by running instructions in the memory.

[0042] Compared with the prior art, the beneficial effects of the electronic device provided by the present invention are the same as those of the brightness temperature correction method described in the above technical solution, and will not be repeated here.

[0043] The present invention also provides a computer storage medium storing instructions that, when executed, implement the above-described brightness temperature correction method.

[0044] Compared with the prior art, the beneficial effects of the computer storage medium provided by the present invention are the same as those of the brightness temperature correction method described in the above technical solution, and will not be repeated here. Attached Figure Description

[0045] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0046] Figure 1 This is a flowchart of the brightness temperature correction method provided in the embodiments of this application;

[0047] Figure 2 This is a structural diagram of the brightness temperature correction device provided in the embodiments of this application;

[0048] Figure 3 This is a schematic diagram of an electronic device structure provided in an embodiment of this application. Detailed Implementation

[0049] To facilitate a clear description of the technical solutions in the embodiments of the present invention, the terms "first" and "second" are used to distinguish identical or similar items with essentially the same function and effect. For example, the first threshold and the second threshold are merely used to distinguish different thresholds and do not limit their order. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or execution order, and that the terms "first" and "second" are not necessarily different.

[0050] It should be noted that in this invention, the terms "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in this invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0051] In this invention, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can represent: a, b, c, a combination of a and b, a combination of a and c, a combination of b and c, or a, b, and c, where a, b, and c can be single or multiple.

[0052] A spaceborne scanning microwave radiometer is a precision brightness temperature measurement device. This device uses a rotating mechanism to drive the antenna-receiver system to perform a conical scan, thereby observing the brightness temperature data of the ground. However, the observed brightness temperature varies at different scanning positions, which is a characteristic of scanning microwave radiometers. The brightness temperature deviation obtained by this observation method is usually large, so it needs to be corrected.

[0053] Traditional methods suggest that the brightness temperature deviation of scanning microwave radiometers in different directions is caused by the radiation from the satellite itself entering the antenna sidelobes. Therefore, usually on both sides of the satellite's flight direction, the further away from the flight direction, the more susceptible it is to the influence of the satellite's own radiation, and the greater the deviation in observed brightness temperature. This deviation presents an irregular shallow U-shape as the azimuth angle changes.

[0054] In the prior art, in order to correct the brightness temperature deviation of scanning microwave radiometers at different azimuths, it is generally believed that this deviation is caused by the radiation brightness temperature of the satellite itself. Moreover, for a fixed azimuth, the deviation caused by the radiation brightness temperature of the satellite itself is also fixed, and the shape and amplitude of its azimuth deviation are unchanged. When correcting, the radiation brightness temperature of the ground object can be simulated and calculated using a radiation transfer model, and the difference between the observed brightness temperature and the simulated brightness temperature at each azimuth angle can be statistically analyzed, thereby correcting the observed brightness temperature at different azimuths.

[0055] However, due to the physical temperature changes of the satellite body, its radiation brightness temperature is actually time-varying. If the satellite body is equivalent to a blackbody, the physical temperature changes of the blackbody will inevitably lead to changes in brightness temperature, which in turn will lead to changes in the satellite body radiation entering the antenna sidelobes.

[0056] Furthermore, existing technologies assume that the deviation caused by satellite antennas for brightness temperature observation is the same in every observation azimuth and will not produce deviations caused by changes in azimuth. Usually, the brightness temperature signal radiated by the antenna is ignored in the calibration. However, in reality, the physical temperature of the satellite antenna and its own radiation change drastically, and the resulting deviation is time-varying and highly correlated with the physical temperature of the antenna.

[0057] To more accurately correct the brightness temperature of satellite observations, this application provides a brightness temperature correction method, apparatus, device, and medium, which will be described in detail in the following embodiments.

[0058] This application first provides a brightness temperature correction method. In one optional embodiment of this application, the subject implementing the brightness temperature correction method can be various types of user terminals such as laptops, tablets, desktop computers, and mobile devices (e.g., mobile phones, personal digital assistants, dedicated messaging devices), or any combination of two or more of these data processing devices, or a server.

[0059] Please refer to Figure 1 , Figure 1 This is a flowchart of the brightness temperature correction method provided in an embodiment of this application.

[0060] like Figure 1 As shown, the brightness temperature correction method includes the following steps S101 to S103:

[0061] S101, based on the physical temperature of the satellite antenna, obtain the first equivalent brightness temperature of the satellite antenna when the satellite is at the first azimuth angle.

[0062] According to blackbody theory, the antenna radiation brightness temperature is calculated by multiplying the antenna emissivity and the antenna physical temperature. In practical applications, the physical temperature of the antenna reflector can be obtained through satellite telemetry parameters. The physical temperature of the antenna reflector can be obtained through the platinum resistance thermometer inside the antenna skin layer.

[0063] Specifically, S101 above includes the following S1 and S2:

[0064] S1, obtain the physical temperature and emissivity of the satellite antenna;

[0065] S2, the product of the satellite antenna and the antenna emissivity is weighted and summed to obtain the first equivalent brightness temperature.

[0066] In practical applications, the first equivalent brightness temperature of the satellite antenna can be obtained by the following formula (1):

[0067] (1);

[0068] in, This represents the first equivalent brightness temperature; j represents the j-th platinum resistance thermometer in the satellite antenna; This represents the physical temperature of the satellite antenna as measured by the j-th platinum resistance thermometer in the satellite antenna. This represents the temperature weight of the j-th platinum resistance thermometer; represents the antenna emissivity; f represents the microwave frequency.

[0069] In practical applications, in order to determine temperature weights and antenna emissivity The method further includes:

[0070] When the azimuth angle of the satellite is zero, the sample observed brightness temperature and sample simulated brightness temperature of the satellite are obtained; based on the sample observed brightness temperature and the sample simulated brightness temperature, the third equivalent brightness temperature of the satellite antenna is determined; based on the latitude of the intersection of the satellite's ascending and descending orbits, the physical temperature of the satellite antenna, and the third equivalent brightness temperature, the emissivity of the antenna and the temperature weights of each platinum resistance thermometer of the satellite antenna are determined; wherein, the platinum resistance thermometer of the satellite antenna is used to measure the physical temperature of the satellite antenna.

[0071] Specifically, temperature weighting and antenna emissivity It can be expressed by the following formulas (2) to (5):

[0072] (2);

[0073] (3);

[0074] (4);

[0075] (5);

[0076] in, This is a correction factor for the antenna emissivity; The conductivity of the reflective surface; Indicates the latitude of the satellite; , , , , The polynomial coefficients of the correction factor are represented. This represents the distance between the j-th platinum resistance thermometer and the focal point of the satellite antenna; c is the antenna focal point; and Represents the coordinates of the j-th platinum resistance thermometer; , , , , The polynomial coefficients represent the temperature weights.

[0077] First, the correction factor for antenna emissivity in formulas (2) and (3) above. As a correction factor, it varies with temperature and is related to the satellite's latitude. Considering that existing technologies may result in inconsistent brightness temperature observations at the intersection of the satellite's ascending and descending orbits during the separate correction of brightness temperature for ascending and descending orbits, the correction results for ascending and descending orbits may not match.

[0078] To address this issue, this application constructs a correction factor for antenna emissivity using the aforementioned formula (3). During the process, the intersection of the satellite's ascent and descent orbits is substituted to ensure that the correction factor for the antenna emissivity is consistent when the satellite ascends to or descends to the intersection. Then, an equation is constructed with the polynomial coefficients of the correction factor as the unknowns, so as to obtain the polynomial coefficients of the correction factor. This ensures that the brightness temperature observation deviation at the intersection of the ascent and descent orbits is consistent during the subsequent calculation of the deviation.

[0079] Secondly, regarding the temperature weight in formula (5) Temperature weighting Distance between platinum resistance and antenna focal length It is inversely proportional to latitude and is also related to latitude, so temperature weights can be constructed using the above formulas (4) and (5). The expression.

[0080] Furthermore, when the scanning azimuth angle is 0°, that is, when the satellite's observation azimuth coincides with its flight azimuth, the antenna radiation enters the main lobe of the antenna pattern, while the satellite's own radiation enters the side lobes of the pattern. At this time, the energy entering the antenna side lobes from both sides of the satellite body is minimal, and the satellite body's radiation is much less than the satellite antenna's radiation.

[0081] That is, filter azimuth angles The observed brightness temperature at the time (i.e., the sample observed brightness temperature) is calculated, and the simulated brightness temperature of the spaceborne microwave radiometer (i.e., the sample simulated brightness temperature) is calculated. Then, the relationship between the equivalent brightness temperature (i.e., the third equivalent brightness temperature of the satellite antenna), the sample observed brightness temperature, and the sample simulated brightness temperature is established as follows: Formula (6) and Formula (7):

[0082] (6);

[0083] (7);

[0084] Where f is the microwave radiation frequency; Indicates the third equivalent brightness temperature; This indicates the brightness temperature of the satellite sample observations; This indicates the simulated brightness temperature of the satellite sample; This represents the distance between the j-th platinum resistance thermometer and the focal point of the satellite antenna; , , , , The polynomial coefficients representing the temperature weights; Indicates the latitude of the satellite; Indicates antenna emissivity; This represents the physical temperature of the satellite antenna as measured by the j-th platinum resistance thermometer.

[0085] Combining formulas (2) to (7) above, when multiple sets of data are obtained, the polynomial coefficients of the correction factor can be fitted. , , , , and the polynomial coefficients of the temperature weights , , , , Substituting the polynomial coefficients obtained from the above fitting into formulas (3) and (5), the antenna emissivity is used to determine the result. Antenna physical temperature and temperature weight Calculate the first equivalent brightness temperature corresponding to different physical temperatures of the satellite antenna at any time.

[0086] S102, based on the first equivalent brightness temperature and the simulated brightness temperature and observed brightness temperature of the satellite when it is at the first azimuth angle, determine the second equivalent brightness temperature of the satellite body when it is at the first azimuth angle.

[0087] In this embodiment of the application, in order to obtain the simulated brightness temperature, the spaceborne scanning microwave radiometer data (such as Level 1 data of HY-2B SMR) can be spatiotemporally matched with the reanalysis ERA5 data to obtain a matching dataset including time, latitude and longitude, observed brightness temperature of each channel, surface type markers (such as ocean, land, sea ice, etc.), sea surface temperature, water vapor, cloud liquid water, wind vector UV component, physical temperature of the satellite body, physical temperature of the satellite antenna, and ascent and descent orbit information. Then, by combining the sea surface temperature, water vapor, cloud liquid water, and wind vector UV component in the matching dataset with the radiative transfer model, the simulated brightness temperature of each channel can be calculated.

[0088] It should be noted that the above-mentioned calculation process for spatiotemporal matching and simulated brightness temperature is existing technology and will not be described in detail here. It is worth noting that the matching of satellite orbital ascent data and orbital descent data is carried out separately in the above spatiotemporal matching process, and the subsequent correction of brightness temperature is also carried out separately for orbital ascent and orbital descent.

[0089] Furthermore, in order to accurately analyze and correct the deviations of the spaceborne scanning microwave radiometer in brightness temperature observations in different directions, it is necessary to perform quality control on the observation data of the spaceborne scanning microwave radiometer. In particular, when the observation data is related to the ocean surface, it is necessary to carefully screen and remove data observed under special meteorological conditions (such as rainfall and rough sea surface).

[0090] In this application embodiment, the following criteria can be applied to screen and remove data observed under special meteorological conditions:

[0091] Sea surface wind speed (SSW) greater than 5 m / s: Strong winds increase sea surface waves and surface roughness, which significantly alters the scattering characteristics of electromagnetic waves by the sea surface, affecting the accuracy of radiative transfer models. Therefore, when the sea surface wind speed observed by satellite exceeds 5 m / s, the observation is considered to be affected by wind and waves, and the observation data may not be applicable to accurate ocean surface parameter inversion; thus, it is marked as invalid.

[0092] Cloud liquid water content (CLW) greater than 0.15 mm: Increased cloud liquid water content indicates thicker clouds or more cloud droplets, which strongly absorbs and scatters radiation transmitted from satellites, thus affecting the accuracy of sea surface parameter measurements. When the liquid water content in the cloud reaches 0.15 mm or more, it indicates that the cloud's influence on radiation is not negligible; observational data such as sea surface temperature obtained at this point may be distorted and should be considered invalid data.

[0093] TB 18H Greater than 180K and / or TB 37H Greater than 220K: Here, "TB" represents the observed brightness temperature, and 18H and 37H refer to specific channels or bands used in satellite remote sensing (i.e., 18GHz and 37GHz). These thresholds are set based on experience or models to identify radiation anomalies that may be caused by rainfall or clouds. When the brightness temperatures of these two bands exceed 180K and 220K respectively, it indicates that the observation results are affected by the strong radiation effect of raindrops or water vapor in clouds, reducing the reliability of the data. Therefore, such observation data should be discarded.

[0094] Furthermore, to further improve the quality of observation data, it is necessary to remove data affected by strong radio frequency (RF) interference. RF interference is non-target radiation generated by external radio signal sources. RF interference can severely affect the microwave signals received by the satellite, especially in low-frequency channels, causing anomalies in the observation data. In practical applications, the following measures can be taken to identify and remove data with strong RF interference:

[0095] The presence of strong radio frequency interference is determined by comparing the difference between the simulated brightness temperature (sim) and the observed brightness temperature (obs) on a specific channel P. Here, channel P specifically refers to any one of the channels 6V, 6H, 10V, or 10H. These channels are usually located at the lower end of the microwave frequency band and are more susceptible to radio frequency interference.

[0096] If the observed brightness temperature of the above channels ( ) and simulated brightness temperature ( The difference between them is greater than 10K, that is... - If the value is greater than 10K, then the observation data of that channel is considered to be affected by strong radio frequency interference and should be marked as observation data that needs to be removed.

[0097] Furthermore, after obtaining the observed brightness temperature, the simulated brightness temperature, and the first equivalent brightness temperature, the second equivalent brightness temperature of the satellite body when the satellite is at the first azimuth angle can be determined.

[0098] Specifically, S102 above includes:

[0099] S3, when the satellite is in the first azimuth angle, determine the observed brightness temperature and simulated brightness temperature of the satellite in different physical temperatures and different latitude ranges;

[0100] S4. Based on the difference between the observed brightness temperature and the simulated brightness temperature and the first equivalent brightness temperature, determine the fourth equivalent brightness temperature of the satellite body in different physical temperatures and different latitude ranges.

[0101] S5, the average value of the fourth equivalent brightness temperature is taken as the second equivalent brightness temperature.

[0102] In practical applications, the equivalent brightness temperature of the satellite body cannot be accurately modeled and calculated, and the emissivity cannot be decomposed. The satellite body observed by the antenna sidelobes is at different angles in different azimuths. Therefore, it is difficult to apply the above-mentioned calculation method of the first equivalent brightness temperature of the satellite antenna to the calculation of the equivalent brightness temperature of the satellite body.

[0103] In this embodiment, the difference between the observed brightness temperature and the simulated brightness temperature at each azimuth angle of each channel can be regarded as the sum of the fourth equivalent brightness temperature of the satellite body and the first equivalent brightness temperature of the satellite antenna corresponding to that azimuth angle. That is, the fourth equivalent brightness temperature of the satellite body can be expressed by the following formula (8):

[0104] (8);

[0105] in, Indicates azimuth. The fourth equivalent brightness temperature of the satellite body is represented at different azimuth angles; f represents the microwave radiation frequency. This represents the difference between the observed brightness temperature and the simulated brightness temperature; This indicates the first equivalent brightness temperature of the satellite antenna.

[0106] Since the equivalent brightness temperature of the satellite body is related to the physical temperature of the satellite body, even if the emissivity of the satellite body cannot be calculated precisely, the emissivity is actually related to the physical temperature of the satellite body. That is, at the same temperature, the emissivity of the satellite body is the same. Using this principle, statistical methods can be used to statistically analyze and average the fourth equivalent brightness temperature of the satellite body at various azimuths in different temperature ranges, and then obtain the second equivalent brightness temperature of the satellite body.

[0107] Specifically, the physical temperature of the satellite can be divided into ranges from -50℃ to 70℃, with a preset temperature range (e.g., 2℃) as the step size, and the latitude of the satellite can be divided into ranges with a preset latitude range (e.g., 5°) as the step size. The fourth equivalent brightness temperature of the satellite at different physical temperatures and latitudes can then be calculated. And calculate their average value. The average value is taken as the second equivalent brightness temperature.

[0108] S103, the sum of the first equivalent brightness temperature and the second equivalent brightness temperature is used as the brightness temperature observation deviation of the satellite at the first azimuth angle, and the observed brightness temperature is corrected.

[0109] The first equivalent brightness temperature of the satellite antenna is calculated using the above S101 and S102. The second equivalent brightness temperature of the satellite body Then, adding the two together gives the brightness temperature observation deviation of the satellite at the first azimuth angle. This brightness temperature observation bias is due to the azimuth angle of the satellite. The microwave radiation frequency f and the physical temperature of the satellite antenna measured by platinum resistance thermometer in the antenna. and the physical temperature of the satellite itself The brightness temperature correction method provided in this application is a function that is constructed rather than a fixed value in traditional methods. Therefore, it can be seen that the brightness temperature correction method can be extended to data correction beyond quality control data. It can correct the observed brightness temperature of the satellite at different azimuth angles using the satellite body temperature, satellite antenna physical temperature and latitude parameters.

[0110] In summary, the brightness temperature correction method provided in this application considers the first equivalent brightness temperature of the satellite antenna and the second equivalent brightness temperature of the satellite body when the satellite is at different azimuth angles during the correction of the observed brightness temperature. The method combines the first equivalent brightness temperature and the second equivalent brightness temperature to correct the observed brightness temperature of the satellite. This method considers the influence of the first equivalent brightness temperature caused by the physical temperature of the satellite antenna and the second equivalent brightness temperature of the satellite body on the observed brightness temperature during the brightness temperature correction process, thereby improving the accuracy of the observed brightness temperature correction.

[0111] Corresponding to the above method embodiments, this application also provides a brightness temperature correction device, please refer to... Figure 2 , Figure 2 This is a structural diagram of the brightness temperature correction device provided in an embodiment of this application.

[0112] like Figure 2 As shown, the brightness temperature correction device includes:

[0113] The first unit 201 is used to obtain the first equivalent brightness temperature of the satellite antenna when the satellite is at the first azimuth angle, based on the physical temperature of the satellite antenna.

[0114] The second unit 202 is used to determine the second equivalent brightness temperature of the satellite body when the satellite is in the first azimuth angle based on the first equivalent brightness temperature and the simulated brightness temperature and observed brightness temperature when the satellite is in the first azimuth angle.

[0115] The third unit 203 is used to use the sum of the first equivalent brightness temperature and the second equivalent brightness temperature as the brightness temperature observation deviation of the satellite at the first azimuth angle, and to correct the observed brightness temperature.

[0116] In one optional embodiment of this application, obtaining the first equivalent brightness temperature of the satellite antenna when the satellite is at a first azimuth angle based on the physical temperature of the satellite antenna includes:

[0117] Obtain the physical temperature and emissivity of the satellite antenna;

[0118] The first equivalent brightness temperature is obtained by weighted summation of the product of the physical temperature of the satellite antenna and the emissivity of the antenna.

[0119] In one optional embodiment of this application, the device is further configured to:

[0120] When the azimuth angle of the satellite is zero, the sample observation brightness temperature and the sample simulated brightness temperature of the satellite are obtained.

[0121] The third equivalent brightness temperature of the satellite antenna is determined based on the observed brightness temperature and the simulated brightness temperature of the sample.

[0122] The emissivity of the antenna and the temperature weights of each platinum resistor of the satellite antenna are determined based on the latitude of the satellite's ascending and descending orbit intersection point, the physical temperature of the satellite antenna, and the third equivalent brightness temperature; wherein, the platinum resistors of the satellite antenna are used to measure the physical temperature of the satellite antenna.

[0123] In one optional embodiment of this application, the first equivalent brightness temperature is obtained by the following formula:

[0124] ;

[0125] in, This represents the first equivalent brightness temperature; j represents the j-th platinum resistance thermometer in the satellite antenna; This represents the physical temperature of the satellite antenna as measured by the j-th platinum resistance thermometer in the satellite antenna. This represents the temperature weight of the j-th platinum resistance thermometer; represents the antenna emissivity; f represents the microwave frequency.

[0126] In one optional embodiment of this application, the antenna emissivity and the temperature weight are obtained by the following formula:

[0127] ;

[0128] ;

[0129] ;

[0130] ;

[0131] in, This is a correction factor for the antenna emissivity; The conductivity of the reflective surface; Indicates the latitude of the satellite; , , , , The polynomial coefficients of the correction factor are represented. This represents the distance between the j-th platinum resistance thermometer and the focal point of the satellite antenna; c is the antenna focal point; and Represents the coordinates of the j-th platinum resistance thermometer; , , , , The polynomial coefficients represent the temperature weights.

[0132] In one optional embodiment of this application, determining the second equivalent brightness temperature of the satellite body at the first azimuth angle based on the first equivalent brightness temperature and the simulated brightness temperature and observed brightness temperature of the satellite at the first azimuth angle includes:

[0133] When the satellite is determined to be at the first azimuth angle, the observed brightness temperature and simulated brightness temperature of the satellite in different physical temperatures and different latitude ranges;

[0134] Based on the difference between the observed brightness temperature and the simulated brightness temperature, and the first equivalent brightness temperature, the fourth equivalent brightness temperature of the satellite body in different physical temperatures and different latitude ranges is determined;

[0135] The average value of the fourth equivalent brightness temperature is used as the second equivalent brightness temperature.

[0136] In one optional embodiment of this application, the fourth equivalent brightness temperature is obtained by the following formula:

[0137] ;

[0138] in, The value represents the difference between the observed brightness temperature and the simulated brightness temperature; f represents the microwave frequency; This indicates the azimuth angle of the satellite; This indicates the first equivalent brightness temperature; This refers to the fourth equivalent brightness temperature.

[0139] The apparatus embodiments provided in this example belong to the same concept as the method embodiments of this application, and can execute the brightness temperature correction method provided in any of the above embodiments of this application, possessing the corresponding functional modules and beneficial effects for executing the brightness temperature correction method. Technical details not described in detail in this example can be found in the specific processing content of the brightness temperature correction method provided in the above embodiments of this application, and will not be repeated here.

[0140] It should be understood that the units in the above device can be implemented by a processor calling software. For example, the device includes a processor connected to a memory containing instructions. The processor calls the instructions stored in the memory to implement any of the above methods or to implement the functions of each unit in the device. The processor can be a general-purpose processor, such as a CPU or microprocessor, and the memory can be internal or external to the device. Alternatively, the units in the device can be implemented as hardware circuits. By designing the hardware circuits, some or all of the unit functions can be implemented. The hardware circuits can be understood as one or more processors. For example, in one implementation, the hardware circuit is an ASIC, and the functions of some or all of the above units are implemented by designing the logical relationships between the components within the circuit. In another implementation, the hardware circuit can be implemented using a PLD, such as an FPGA, which can include a large number of logic gates. The connection relationships between the logic gates are configured through configuration files to implement the functions of some or all of the above units. All units in the above device can be implemented entirely by a processor calling software, entirely by hardware circuits, or partially by a processor calling software with the remaining parts implemented by hardware circuits.

[0141] In this application embodiment, a processor is a circuit with signal processing capabilities. In one implementation, the processor can be a circuit with instruction reading and execution capabilities, such as a CPU, microprocessor, GPU, or DSP. In another implementation, the processor can implement certain functions through the logical relationships of hardware circuits. These logical relationships are fixed or reconfigurable. For example, the processor may be a hardware circuit implemented as an ASIC or PLD, such as an FPGA. In a reconfigurable hardware circuit, the process of the processor loading a configuration document and configuring the hardware circuit can be understood as the processor loading instructions to implement the functions of some or all of the above units. Furthermore, it can also be a hardware circuit designed for artificial intelligence, which can be understood as an ASIC, such as an NPU, TPU, or DPU.

[0142] As can be seen, each unit in the above device can be one or more processors (or processing circuits) configured to implement the above methods, such as: CPU, GPU, NPU, TPU, DPU, microprocessor, DSP, ASIC, FPGA, or a combination of at least two of these processor forms.

[0143] Furthermore, the units in the above devices can be integrated in whole or in part, or they can be implemented independently. In one implementation, these units are integrated together and implemented in the form of a System-on-Chip (SoC). The SoC may include at least one processor for implementing any of the above methods or implementing the functions of the units in the device. The at least one processor may be of different types, such as CPU and FPGA, CPU and artificial intelligence processor, CPU and GPU, etc.

[0144] This application also provides an electronic device, please refer to... Figure 3 , Figure 3 This is a schematic diagram of an electronic device structure provided in an embodiment of this application.

[0145] like Figure 3 As shown, the electronic device includes:

[0146] Processor 210;

[0147] Memory 200 for storing executable instructions of the processor 210;

[0148] The processor 210 is configured to execute the brightness temperature correction method disclosed in any of the above embodiments by running instructions in the memory 200.

[0149] The processor 210, memory 200, communication interface 220, input device 230, and output device 240 are interconnected via a bus. Among them:

[0150] A bus can include a pathway for transmitting information between various components of a computer system.

[0151] Processor 210 can be a general-purpose processor, such as a general-purpose central processing unit (CPU), a microprocessor, etc., or an application-specific integrated circuit (ASIC), or one or more integrated circuits used to control the execution of the program of the present invention. It can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), an off-the-shelf programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0152] Processor 210 may include a main processor, as well as a baseband chip, modem, etc.

[0153] The memory 200 stores a program that executes the technical solution of this invention, and may also store an operating system and other key business functions. Specifically, the program may include program code, which includes computer operation instructions. More specifically, the memory 200 may include read-only memory (ROM), other types of static storage devices capable of storing static information and instructions, random access memory (RAM), other types of dynamic storage devices capable of storing information and instructions, disk storage, flash memory, etc.

[0154] Input device 230 may include a device for receiving user input data and information, such as a keyboard, mouse, camera, scanner, touch screen, etc.

[0155] Output device 240 may include devices that allow information to be output to a user, such as a display screen, printer, speaker, etc.

[0156] The communication interface 220 may include a device that uses any transceiver to communicate with other devices or communication networks, such as Ethernet, Radio Access Network (RAN), Wireless Local Area Network (WLAN), etc.

[0157] The processor 210 executes the program stored in the memory 200 and calls other devices, and can be used to implement each step of any of the brightness temperature correction methods provided in the above embodiments of this application.

[0158] In addition to the methods and devices described above, embodiments of this application may also be computer program products, which include computer program instructions that, when executed by a processor, cause the processor to perform the steps in the brightness temperature correction methods of various embodiments of this application.

[0159] The computer program product can be written in any combination of one or more programming languages ​​to perform the operations of the embodiments of this application. The programming languages ​​include object-oriented programming languages ​​such as Java and C++, as well as conventional procedural programming languages ​​such as C or similar languages. The program code can be executed entirely on the user's computing device, partially on the user's computing device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0160] Furthermore, embodiments of this application may also be storage media storing a computer program thereon, the computer program being executed by a processor of the steps in the brightness temperature correction methods of various embodiments of this application.

[0161] For the foregoing method embodiments, in order to simplify the description, they are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, because according to this application, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0162] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For apparatus embodiments, since they are basically similar to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0163] The steps in the methods of the various embodiments of this application can be adjusted, merged, or deleted in order according to actual needs, and the technical features described in each embodiment can be replaced or combined.

[0164] The modules and sub-modules in the apparatus and terminal in the various embodiments of this application can be merged, divided, and deleted according to actual needs.

[0165] It should be understood that the disclosed terminals, devices, and methods can be implemented in other ways, given the several embodiments provided in this application. For example, the terminal embodiments described above are merely illustrative. For instance, the division of modules or sub-modules is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple sub-modules or modules may be combined or integrated into another module, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces, devices, or modules, and may be electrical, mechanical, or other forms.

[0166] The modules or submodules described as separate components may or may not be physically separate. The components that constitute a module or submodule may or may not be physical modules or submodules; that is, they may be located in one place or distributed across multiple network modules or submodules. Some or all of the modules or submodules can be selected to achieve the purpose of this embodiment's solution, depending on actual needs.

[0167] Furthermore, the functional modules or sub-modules in the various embodiments of this application can be integrated into one processing module, or each module or sub-module can exist physically separately, or two or more modules or sub-modules can be integrated into one module. The integrated modules or sub-modules described above can be implemented in hardware or in the form of software functional modules or sub-modules.

[0168] Those skilled in the art will further 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, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. 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.

[0169] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly by hardware, a software unit executed by a processor, or a combination of both. The software unit can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0170] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0171] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A brightness temperature correction method, characterized in that, include: Based on the physical temperature of the satellite antenna, the first equivalent brightness temperature of the satellite antenna when the satellite is at the first azimuth angle is obtained; Based on the first equivalent brightness temperature, and the simulated brightness temperature and observed brightness temperature of the satellite when it is at the first azimuth angle, determine the second equivalent brightness temperature of the satellite body when it is at the first azimuth angle; The sum of the first equivalent brightness temperature and the second equivalent brightness temperature is used as the brightness temperature observation deviation of the satellite at the first azimuth angle, and the observed brightness temperature is corrected accordingly. The first equivalent brightness temperature is obtained by the following formula: ； in, This represents the first equivalent brightness temperature; j represents the j-th platinum resistance thermometer in the satellite antenna; This represents the physical temperature of the satellite antenna as measured by the j-th platinum resistance thermometer in the satellite antenna. This represents the temperature weight of the j-th platinum resistance thermometer; The antenna emissivity is represented by f; the microwave frequency is represented by f. The antenna emissivity and the temperature weight are obtained by the following formulas: ； ； ； ； in, This is a correction factor for the antenna emissivity; The conductivity of the reflective surface; Indicates the latitude of the satellite; , , , , The polynomial coefficients of the correction factor are represented. This represents the distance between the j-th platinum resistance thermometer and the focal point of the satellite antenna; c is the antenna focal point; and Represents the coordinates of the j-th platinum resistance thermometer; , , , , The polynomial coefficients representing the temperature weights; The step of determining the second equivalent brightness temperature of the satellite body when it is at the first azimuth angle, based on the first equivalent brightness temperature and the simulated brightness temperature and observed brightness temperature of the satellite at the first azimuth angle, includes: When the satellite is determined to be at the first azimuth angle, the observed brightness temperature and simulated brightness temperature of the satellite in different physical temperatures and different latitude ranges; Based on the difference between the observed brightness temperature and the simulated brightness temperature, and the first equivalent brightness temperature, the fourth equivalent brightness temperature of the satellite body in different physical temperatures and different latitude ranges is determined; The average value of the fourth equivalent brightness temperature is used as the second equivalent brightness temperature.

2. The brightness temperature correction method according to claim 1, characterized in that, The step of obtaining the first equivalent brightness temperature of the satellite antenna when the satellite is at a first azimuth angle based on the physical temperature of the satellite antenna includes: Obtain the physical temperature and emissivity of the satellite antenna; The first equivalent brightness temperature is obtained by weighted summation of the product of the physical temperature of the satellite antenna and the emissivity of the antenna.

3. The brightness temperature correction method according to claim 2, characterized in that, Also includes: When the azimuth angle of the satellite is zero, the sample observation brightness temperature and the sample simulated brightness temperature of the satellite are obtained. The third equivalent brightness temperature of the satellite antenna is determined based on the observed brightness temperature and the simulated brightness temperature of the sample. The emissivity of the antenna and the temperature weights of each platinum resistor of the satellite antenna are determined based on the latitude of the satellite's ascending and descending orbit intersection point, the physical temperature of the satellite antenna, and the third equivalent brightness temperature; wherein, the platinum resistors of the satellite antenna are used to measure the physical temperature of the satellite antenna.

4. The brightness temperature correction method according to claim 1, characterized in that, The fourth equivalent brightness temperature is obtained by the following formula: ； in, The value represents the difference between the observed brightness temperature and the simulated brightness temperature; f represents the microwave frequency; This indicates the azimuth angle of the satellite; This indicates the first equivalent brightness temperature; This refers to the fourth equivalent brightness temperature.

5. A brightness temperature correction device, characterized in that, The brightness temperature correction method according to claim 1 is employed, and the apparatus comprises: The first unit is used to obtain the first equivalent brightness temperature of the satellite antenna when the satellite is at the first azimuth angle, based on the physical temperature of the satellite antenna. The second unit is used to determine the second equivalent brightness temperature of the satellite body when the satellite is in the first azimuth angle based on the first equivalent brightness temperature and the simulated brightness temperature and observed brightness temperature when the satellite is in the first azimuth angle. The third unit is used to correct the observed brightness temperature by taking the sum of the first equivalent brightness temperature and the second equivalent brightness temperature as the brightness temperature observation deviation of the satellite at the first azimuth angle.

6. An electronic device, characterized in that, include: processor; Memory used to store the processor's executable instructions; The processor is configured to execute the brightness temperature correction method according to any one of claims 1 to 4 by running instructions in the memory.

7. A computer storage medium, characterized in that, The computer storage medium stores instructions that, when executed, implement the brightness temperature correction method according to any one of claims 1 to 4.

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