An on-orbit calibration accuracy evaluation method for a stationary orbit microwave radiometer calibration system

Abstract

This application provides a method, device, and computer-readable storage medium for evaluating the on-orbit calibration error of a microwave radiometer calibration system used in geostationary orbit. The application evaluates the on-orbit calibration error of the microwave radiometer calibration system by determining the errors of the calibration cold source, calibration heat source, Earth observation radiation brightness temperature, and Earth target brightness temperature. By separately evaluating the errors of the calibration cold source, calibration heat source, Earth observation radiation brightness temperature, and Earth target brightness temperature in the microwave radiometer calibration system used in geostationary orbit, each error is quantified, thus quantifying the on-orbit calibration error of the microwave radiometer calibration system. Furthermore, the different radiation transmission paths are considered during the evaluation of each error, making the evaluation of the sources of on-orbit calibration error of the microwave radiometer calibration system used in geostationary orbit not only effective and accurate but also highly implementable.

Description

Technical Field

[0001] This application relates to the field of microwave remote sensing technology, and in particular to an on-orbit calibration error assessment method, device and computer-readable storage medium for a microwave radiometer calibration system used in geostationary orbit. Background Technology

[0002] This section is intended to provide background or context for the embodiments of this application as set forth in the claims. The description herein is not to be construed as prior art simply because it is included in this section.

[0003] Microwaves can penetrate clouds and rain effectively, enabling all-day, all-weather observation. Simultaneously, clouds, rain, and the atmospheric medium affect microwave radiation transmission through absorption, emission, and scattering. These absorption, emission, and scattering effects are related to the atmospheric thermodynamic structure and the microscopic and macroscopic physical properties of clouds and rain. Therefore, data from microwave payloads can be used to infer the thermodynamic structure and physical properties of clouds and rain, making it a crucial tool for atmospheric observation.

[0004] Geostationary microwave radiometer technology is a crucial technology for geostationary microwave meteorological satellites. The long revisit periods of polar-orbiting satellites limit the application of polar-orbiting meteorological satellite observations in monitoring and early warning of rapidly evolving severe weather events. Even with a network of polar-orbiting satellites, it is still difficult to fully meet the observational needs of weather forecasting for rapidly changing atmospheric humidity, thermal states, heavy rainfall, and severe convection. Monitoring these rapidly evolving severe weather phenomena and processes that require high temporal resolution can only be achieved through geostationary meteorological satellites. Geostationary satellites have significant advantages in terms of observational field of view and temporal resolution. Equipping microwave remote sensing instruments on a geostationary satellite platform can effectively improve the temporal resolution of observations, enhance the meteorological satellite's ability to detect clouds and rain, achieve large-scale Earth coverage in a short time, and provide high-frequency observational data.

[0005] With the increasing demands of passive microwave remote sensing technology and meteorological applications, microwave radiometers face ever-higher requirements for accuracy and spatiotemporal resolution. Developing geostationary orbit atmospheric microwave sounding technology to achieve all-weather, all-time observation of the Earth can effectively improve the accuracy of weather forecasts. Geostationary orbit microwave radiometers employ the principle of passive microwave remote sensing to detect various atmospheric parameters such as atmospheric temperature profiles, humidity profiles, precipitation, and clouds in multiple dimensions. A microwave radiometer is a passive receiving system consisting of an antenna and a receiver. On-orbit calibration of geostationary orbit microwave radiometers generally uses a two-point calibration method. Based on the system design, a blackbody calibration source and cold air are used as the thermal and cold calibration sources, respectively. A functional relationship is established between the blackbody calibration source test voltage and the cold air test voltage and the brightness temperature of the thermal calibration source and the cold air, converting the target observation voltage into the target observation brightness temperature. The calibration accuracy of microwave radiometers is a key factor affecting the quantitative application of their observation data; achieving on-orbit calibration accuracy assessment can strongly support the quantitative scientific application of geostationary orbit microwave observation data. Summary of the Invention

[0006] This application provides a method, apparatus, and computer-readable storage medium for evaluating the on-orbit calibration error of a microwave radiometer calibration system used in geostationary orbit, for the purpose of evaluating the on-orbit calibration accuracy of a geostationary microwave radiometer.

[0007] One aspect of this application provides an on-orbit calibration error evaluation method for a microwave radiometer calibration system used in geostationary orbit, wherein the method includes:

[0008] Step 1: Determine the brightness temperature of the calibration cold source based on the radiation transmission path of the calibration cold source in the microwave radiometer calibration system and the influencing factors of the calibration cold source.

[0009] Step 2: Determine the error of the calibration cold source based on its brightness temperature;

[0010] Step 3: Determine the brightness temperature of the calibration heat source based on the radiation transmission path of the calibration heat source in the microwave radiometer calibration system and the influencing factors of the calibration heat source;

[0011] Step 4: Determine the error of the calibration heat source based on its brightness temperature;

[0012] Step 5: Determine the brightness temperature of the Earth antenna target based on the radiation transmission path of the Earth radiation during Earth observation by the microwave radiometer calibration system and the influencing factors of the brightness temperature of the Earth antenna target.

[0013] Step 6: Determine the error of the Earth observation radiation brightness temperature based on the Earth antenna target brightness temperature;

[0014] Step 7: Evaluate the on-orbit calibration error of the microwave radiometer calibration system based on the error of the calibration cold source, the error of the calibration heat source, the error of the Earth observation radiation brightness temperature, and the brightness temperature of the Earth target.

[0015] Another aspect of this application provides an on-orbit calibration error evaluation device for a microwave radiometer calibration system used in geostationary orbit, wherein the device includes:

[0016] The first determining module is used to determine the brightness temperature of the calibration cold source based on the radiation transmission path of the calibration cold source in the microwave radiometer calibration system and the influencing factors of the calibration cold source.

[0017] The second determining module is used to determine the error of the calibration cold source based on the brightness temperature of the calibration cold source;

[0018] The third determining module is used to determine the brightness temperature of the calibration heat source by considering the radiation transmission path of the calibration heat source and the influencing factors of the calibration heat source in the microwave radiometer calibration system.

[0019] The fourth determining module is used to determine the error of the calibration heat source based on the brightness temperature of the calibration heat source;

[0020] The fifth determining module is used to determine the brightness temperature of the Earth antenna target based on the radiation transmission path of the Earth's radiation during Earth observation by the microwave radiometer calibration system and the influencing factors of the brightness temperature of the Earth antenna target.

[0021] The sixth determining module is used to determine the error of the Earth observation radiation brightness temperature based on the brightness temperature of the Earth antenna target;

[0022] The evaluation module is used to evaluate the on-orbit calibration error of the microwave radiometer calibration system based on the error of the calibration cold source, the error of the calibration heat source, the error of the Earth observation radiation brightness temperature, and the brightness temperature of the Earth target.

[0023] Another aspect of this application provides an electronic device, comprising:

[0024] At least one processor; and

[0025] A memory communicatively connected to the at least one processor; wherein,

[0026] The memory stores instructions that can be executed by the at least one processor to enable the at least one processor to perform an on-orbit calibration error assessment method for a microwave radiometer calibration system used in a geostationary orbit as described above.

[0027] Another aspect of this application provides a computer-readable storage medium having computer program instructions stored thereon, which can be executed by a processor to implement the on-orbit calibration error assessment method for a microwave radiometer calibration system used in a geostationary orbit.

[0028] This application provides an on-orbit calibration error assessment method for a microwave radiometer calibration system used in geostationary orbit. By determining the errors of the calibration cold source, calibration heat source, Earth observation radiation brightness temperature, and Earth target brightness temperature, the on-orbit calibration error of the microwave radiometer calibration system is assessed. In other words, by employing error analysis methods, the errors of the calibration cold source, calibration heat source, Earth observation radiation brightness temperature, and Earth target brightness temperature in the microwave radiometer calibration system used in geostationary orbit are assessed separately, quantifying each error and thus quantifying the on-orbit calibration error of the microwave radiometer calibration system. Furthermore, the different radiation transmission paths are considered during the assessment of each error, making the assessment of the sources of on-orbit calibration error of the microwave radiometer calibration system used in geostationary orbit not only effective and accurate, but also providing a scientific basis for improving the calibration design scheme of future geostationary orbit instruments and for the quantitative use of geostationary microwave observation data. This method is highly implementable. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0031] Figure 1 A flowchart illustrating an on-orbit calibration error assessment method for a microwave radiometer calibration system used in a geostationary orbit, provided as an embodiment of this application;

[0032] Figure 2 This diagram illustrates the various radiation transmission optical paths in a microwave radiometer calibration system used in a stationary orbit according to an embodiment of this application.

[0033] Figure 2 (a) shows a schematic diagram of the radiation transmission optical path of Earth's radiation during Earth observation using a microwave radiometer calibration system.

[0034] Figure 2 (b) shows a schematic diagram of the radiation transmission optical path of the calibration cold source in the microwave radiometer calibration system;

[0035] Figure 2 (c) shows a schematic diagram of the radiation transmission optical path of the calibration heat source in the microwave radiometer calibration system;

[0036] Figure 3 A schematic diagram of the device structure for an on-orbit calibration error assessment device of a microwave radiometer calibration system used in a geostationary orbit, provided as another embodiment of this application;

[0037] Figure 4 This is a schematic diagram of the structure of an electronic device suitable for implementing the solutions in the embodiments of this application.

[0038] The same or similar reference numerals in the accompanying drawings represent the same or similar parts. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0040] In a typical configuration of this application, the terminal and the service network devices each include one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0041] Memory may include non-persistent storage in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0042] Computer-readable media include permanent and non-permanent, removable and non-removable media, which can store information by any method or technology. Information can be computer program instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, read-only optical disc (CD-ROM), digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transfer medium that can be used to store information accessible by a computing device.

[0043] This application provides an on-orbit calibration error evaluation method for a microwave radiometer calibration system used in geostationary orbit, wherein the method includes:

[0044] Step 1: Determine the brightness temperature of the calibration cold source based on the radiation transmission path of the calibration cold source in the microwave radiometer calibration system and the influencing factors of the calibration cold source.

[0045] Step 2: Determine the error of the calibration cold source based on its brightness temperature;

[0046] Step 3: Determine the brightness temperature of the calibration heat source based on the radiation transmission path of the calibration heat source in the microwave radiometer calibration system and the influencing factors of the calibration heat source;

[0047] Step 4: Determine the error of the calibration heat source based on its brightness temperature;

[0048] Step 5: Determine the brightness temperature of the Earth antenna target based on the radiation transmission path of the Earth radiation during Earth observation by the microwave radiometer calibration system and the influencing factors of the brightness temperature of the Earth antenna target.

[0049] Step 6: Determine the error of the Earth observation radiation brightness temperature based on the Earth antenna target brightness temperature;

[0050] Step 7: Evaluate the on-orbit calibration error of the microwave radiometer calibration system based on the error of the calibration cold source, the error of the calibration heat source, the error of the Earth observation radiation brightness temperature, and the brightness temperature of the Earth target.

[0051] In practical scenarios, the execution entity of this method can be the microwave radiometer itself, or other electronic devices used to evaluate the on-orbit calibration error of the microwave radiometer calibration system, such as computing devices or data processing devices, or it can be a device composed of the microwave radiometer and other electronic devices. Here, the computing device or data processing device includes, but is not limited to, an electronic device capable of automatically performing numerical calculations and information processing according to pre-set or stored instructions, and its hardware includes, but is not limited to, microprocessors, application-specific integrated circuits (ASICs), programmable gate arrays (FPGAs), digital digital processors (DSPs), embedded devices, etc.

[0052] Figure 1 This document illustrates a flowchart of an on-orbit calibration error assessment method for a microwave radiometer calibration system used in geostationary orbit, as provided in an embodiment of this application. It should be noted that steps 1, 2, 3, 4, 5, 6, and 7 are not reference numerals in the accompanying drawings. Specifically, the method includes:

[0053] Step 1: Determine the brightness temperature of the calibration cold source based on the radiation transmission path of the calibration cold source in the microwave radiometer calibration system and the influencing factors of the calibration cold source.

[0054] Step 2: Determine the error of the calibration cold source based on its brightness temperature;

[0055] Step 3: Determine the brightness temperature of the calibration heat source based on the radiation transmission path of the calibration heat source in the microwave radiometer calibration system and the influencing factors of the calibration heat source;

[0056] Step 4: Determine the error of the calibration heat source based on its brightness temperature;

[0057] Step 5: Determine the brightness temperature of the Earth antenna target based on the radiation transmission path of the Earth radiation during Earth observation by the microwave radiometer calibration system and the influencing factors of the brightness temperature of the Earth antenna target.

[0058] Step 6: Determine the error of the Earth observation radiation brightness temperature based on the Earth antenna target brightness temperature;

[0059] Step 7: Evaluate the on-orbit calibration error of the microwave radiometer calibration system based on the error of the calibration cold source, the error of the calibration heat source, the error of the Earth observation radiation brightness temperature, and the brightness temperature of the Earth target.

[0060] Specifically, in step 1, the brightness temperature of the calibration cold source is determined based on the radiation transmission path of the calibration cold source in the microwave radiometer calibration system and the influencing factors of the calibration cold source.

[0061] Here, the calibration cold source refers to a low brightness temperature target source used for microwave radiometer calibration; for on-orbit microwave radiometers, this typically refers to the cosmic background radiation. The radiation transmission path of the calibration cold source is: cosmic background radiation → microwave radiometer cold space plane mirror → microwave radiometer quasi-optical network → microwave radiometer receiver. Figure 2 (b) shows a schematic diagram of the radiation transmission optical path of the calibration cold source in the microwave radiometer calibration system.

[0062] Cosmic microwave background radiation refers to isotropic microwave radiation originating from the background of outer space, also known as microwave background radiation. A cold-air plane mirror in a microwave radiometer is a plane mirror used in the calibration system of a microwave radiometer to reflect cold-air radiation. A quasi-optical network (QON) in a microwave radiometer refers to the quasi-optical feed network used in the calibration system of a microwave radiometer. A microwave radiometer receiver is a receiver that receives microwave radiation.

[0063] Here, the influencing factors of the calibration cold source include at least one of the following: the brightness temperature of the cosmic background radiation received in the main lobe beam direction of the microwave radiometer cold space plane mirror, the brightness temperature of the equivalent side lobe beam of the microwave radiometer cold space plane mirror, and the brightness temperature of the self-radiation of the microwave radiometer cold space plane mirror.

[0064] Here, the brightness temperature of the calibration cold source is determined by means of:

[0065] The brightness temperature of the calibration cold source is determined by combining the following formula (1);

[0066] T C =(1-α) C )[η C T Cos +(1-η C )T CE ]+α C T C0 (1)

[0067] Among them, T C α represents the brightness temperature of the calibration cold source. C η is the emissivity of the cold-air plane mirror of the microwave radiometer. C T represents the main lobe beam efficiency of the cold-air plane mirror of the microwave radiometer. Cos T CE T C0 These represent the brightness temperature of the cosmic background radiation, the equivalent sidelobe beam brightness temperature of the cold-space plane mirror of the microwave radiometer, and the physical temperature of the cold-space plane mirror of the microwave radiometer, respectively.

[0068] First, it should be noted that in an antenna, the beam range (or beam solid angle) is composed of the main lobe range (or solid angle) plus the side lobe range (or solid angle). The (main) beam efficiency is the ratio of the power radiated (or received) by the (main) beam to the total power radiated (or received) by the (total) beam. Therefore, the main lobe beam efficiency of a microwave radiometer's cold-space plane mirror refers to the ratio of the power radiated by the main lobe beam of the microwave radiometer's cold-space plane mirror to the total power radiated by the total beam of the microwave radiometer's cold-space plane mirror. The cosmic background radiation brightness temperature refers to the brightness temperature radiated by the cosmic background. The equivalent sidelobe beam brightness temperature of a microwave radiometer's cold-space plane mirror refers to the brightness temperature received by the side lobes (other than the main lobe).

[0069] Self-radiation brightness temperature is equal to physical temperature multiplied by emissivity. For example, the self-radiation brightness temperature of a cold-space plane mirror in a microwave radiometer is equal to the physical temperature of the cold-space plane mirror multiplied by the emissivity of the cold-space plane mirror.

[0070] Step 2: Determine the error of the calibration cold source based on the brightness temperature of the calibration cold source.

[0071] Specifically, each parameter in the above formula (1) is compared with T. C Taking the partial derivative, we obtain the following formula (2). Then, we determine the error of the calibration cold source according to formula (2):

[0072]

[0073] Where, δT C δα represents the error of the calibration cold source. C δη represents the emissivity error of the cold-air plane mirror of the microwave radiometer. C The main lobe beam efficiency error of the cold-air plane mirror of the microwave radiometer is represented by δT. CE δT represents the equivalent sidelobe beam brightness temperature error of the cold-air plane mirror of the microwave radiometer. C0 This indicates the physical temperature measurement error of the cold air plane mirror of the microwave radiometer.

[0074] Step 3: Determine the brightness temperature of the calibration heat source based on the radiation transmission path of the calibration heat source in the microwave radiometer calibration system and the influencing factors of the calibration heat source.

[0075] Here, the calibration heat source refers to a high brightness temperature target source used for microwave radiometer calibration. In a specific embodiment, the calibration heat source can be a calibration heat source blackbody. The radiation transmission path of the calibration heat source is: calibration heat source blackbody → microwave radiometer quasi-optical network → microwave radiometer receiver. The influencing factors of the calibration heat source include at least one of the following: the heat source radiation brightness temperature of the calibration heat source blackbody and the equivalent sidelobe brightness temperature of the calibration heat source blackbody. Figure 2(c) shows a schematic diagram of the radiation transmission optical path of the calibration heat source in the microwave radiometer calibration system.

[0076] The brightness temperature of the calibrated blackbody's radiation refers to the brightness temperature radiated by the blackbody. The equivalent sidelobe brightness temperature of the calibrated blackbody refers to the equivalent brightness temperature radiated outward from the sidelobes of the blackbody.

[0077] Here, the brightness temperature of the calibration heat source is determined by means of:

[0078] The brightness temperature of the calibration heat source is determined by combining the following formula (3):

[0079] T H =η H εT Hotload +(1-η H )T HE (3)

[0080] Among them, T H T represents the brightness temperature of the calibration heat source. Hotload T HE η represents the calibration source temperature of the calibration heat source blackbody and the equivalent sidelobe brightness temperature of the calibration heat source blackbody, respectively. H ε represents the main beam efficiency of the calibrated blackbody, and ε represents the emissivity of the calibrated blackbody.

[0081] Step 4: Determine the error of the calibration heat source based on its brightness temperature, such as by calculating T for each parameter in formula (3). H Partial derivatives yield the following formula (4), which is used to determine the error of the calibration heat source according to formula (4):

[0082]

[0083] Where, δT H δη represents the error of the calibration heat source. H δT represents the main beam efficiency error of the calibrated blackbody heat source. HE δε represents the equivalent sidelobe brightness temperature error of the calibrated thermal source blackbody, and δT represents the emissivity error of the calibrated thermal source blackbody. Hotload This indicates the temperature error of the calibrated heat source.

[0084] Step 5: Determine the brightness temperature of the Earth antenna target based on the radiation transmission path of the Earth radiation during Earth observation by the microwave radiometer calibration system and the influencing factors of the brightness temperature of the Earth antenna target.

[0085] The radiation transmission path of Earth's radiation during Earth observation by the microwave radiometer calibration system is as follows: Earth target → microwave radiometer primary reflector → microwave radiometer secondary reflector → microwave radiometer quasi-optical network → microwave radiometer receiver. Here, the Earth target refers to the target observed by the microwave radiometer calibration system during Earth observation. Figure 2 (a) shows a schematic diagram of the radiation transmission optical path of Earth's radiation during Earth observation by a microwave radiometer calibration system.

[0086] The factors affecting the brightness temperature of the Earth antenna target include at least one of the following: the brightness temperature of the main lobe beam direction of the microwave radiometer's main reflector is reflected by the microwave radiometer's main reflector and sub-reflector; the brightness temperature of the side lobe beam of the microwave radiometer's main reflector is reflected by the microwave radiometer's main reflector and sub-reflector; the self-radiation brightness temperature of the microwave radiometer's main reflector; and the self-radiation brightness temperature of the microwave radiometer's sub-reflector.

[0087] The methods for determining the brightness temperature of the Earth antenna target include:

[0088] The brightness temperature of the Earth target antenna is determined by combining the following formula (5):

[0089] T A =(1-α) M )(1-α S )[η A T B +(1-η A )T AE ]

[0090] +α M (1-α S )T M0

[0091] +a S T S0 (5)

[0092] Among them, T A α represents the brightness temperature of the Earth antenna target. M α S T represents the emissivity of the primary reflector and the emissivity of the secondary reflector of the microwave radiometer, respectively; M0 T S0 η represents the physical temperature of the primary reflector and the secondary reflector of the microwave radiometer, respectively; A The main lobe beam efficiency of the main and sub-reflector antennas of the microwave radiometer during Earth observation; T AE The equivalent sidelobe beam brightness temperature of the main and secondary antenna reflectors of the microwave radiometer during Earth observation; T B Brightness temperature for Earth targets.

[0093] Step 6: Determine the error of the Earth observation radiation brightness temperature based on the Earth antenna target brightness temperature.

[0094] Find T for each parameter in formula (5). H Partial derivatives yield the following formula (6), which is used to determine the error of the Earth observation radiation brightness temperature according to formula (6):

[0095]

[0096] Where, δT A δα represents the error in the Earth observation radiation brightness temperature. M δα represents the emissivity error of the primary reflector of the microwave radiometer. S δη represents the emissivity error of the sub-reflector of the microwave radiometer. A δT represents the main lobe beam efficiency error of the reflector antenna during Earth observation. AE δT represents the equivalent sidelobe beam brightness temperature error of the antenna reflector during Earth observation. M0 δT represents the physical temperature error of the primary reflector of the microwave radiometer. S0 This indicates the physical temperature error of the sub-reflector of the microwave radiometer.

[0097] In one embodiment, the method further includes:

[0098] Based on the aforementioned microwave radiometer calibration principle, a calibration equation for the microwave radiometer is established, leading to the calibration equation for the brightness temperature of the Earth target antenna:

[0099]

[0100] Among them, T A T C T H V represents the brightness temperature of the Earth target antenna, the brightness temperature of the calibration cold source, and the brightness temperature of the calibration heat source, respectively. A V C V H These represent the voltage count values ​​of the Earth antenna target, the voltage count values ​​of the calibration cold source, and the voltage count values ​​of the calibration heat source, respectively.

[0101] In one embodiment, if there are errors in the brightness temperature of the calibration heat source, the brightness temperature of the calibration cold source, and the brightness temperature of the Earth antenna target, the calibration equation (7) can be written as:

[0102]

[0103] Among them, T′ H and T′ C T′ represents the brightness temperature of the calibration heat source and the brightness temperature of the calibration cold source when errors exist.A This indicates that when both the calibration heat source and the calibration cold source have errors, the microwave radiometer includes the antenna brightness temperature of the Earth observation with errors.

[0104] Step 7: Based on the errors of the calibration cold source, the calibration heat source, the Earth observation radiation brightness temperature, and the Earth target brightness temperature, evaluate the on-orbit calibration error of the microwave radiometer calibration system. Specifically, evaluate the on-orbit calibration error of the microwave radiometer calibration system using the following formula (9):

[0105]

[0106] Where, δT ∑ This indicates the on-orbit calibration error of the microwave radiometer calibration system.

[0107] It should be noted that, in specific embodiments, steps 1, 3, and 5 can be executed in parallel or in sequence; steps 2, 4, and 6 can be executed in parallel or in sequence.

[0108] Furthermore, this application also provides an on-orbit calibration error evaluation device for a microwave radiometer calibration system used in geostationary orbit, the structure of which is as follows: Figure 3 As shown. The device includes a first determining module 301, a second determining module 302, a third determining module 303, a fourth determining module 304, a fifth determining module 305, a sixth determining module 306, and an evaluation module 307.

[0109] Specifically, the first determining module 301 determines the brightness temperature of the calibration cold source based on the radiation transmission path of the calibration cold source in the microwave radiometer calibration system and the influencing factors of the calibration cold source; the second determining module 302 determines the error of the calibration cold source based on the brightness temperature of the calibration cold source; the third determining module 303 determines the brightness temperature of the calibration heat source based on the radiation transmission path of the calibration heat source in the microwave radiometer calibration system and the influencing factors of the calibration heat source; and the fourth determining module 304 determines the brightness temperature of the calibration heat source based on the brightness temperature of the calibration heat source. Error; the fifth determining module 305 determines the brightness temperature of the Earth antenna target based on the radiation transmission path of the Earth radiation during Earth observation by the microwave radiometer calibration system and the influencing factors of the brightness temperature of the Earth antenna target; the sixth determining module 306 determines the error of the Earth observation radiation brightness temperature based on the brightness temperature of the Earth antenna target; the evaluation module 307 evaluates the on-orbit calibration error of the microwave radiometer calibration system based on the error of the calibration cold source, the error of the calibration heat source, the error of the Earth observation radiation brightness temperature, and the brightness temperature of the Earth target.

[0110] It should be noted that, in specific embodiments, the first determining module 301, the third determining module 303, and the fifth determining module 305 can be executed in parallel or in sequence; the second determining module 302, the fourth determining module 304, and the sixth determining module 306 can be executed in parallel or in sequence.

[0111] The embodiments of the above modules are the same as or substantially similar to the corresponding steps in the aforementioned method for evaluating the on-orbit calibration error of a microwave radiometer calibration system used in a geostationary orbit. For the sake of brevity, they will not be repeated here, but are incorporated herein by reference.

[0112] Based on the same inventive concept, this application also provides an electronic device. The method corresponding to the electronic device can be an on-orbit calibration error evaluation method for a microwave radiometer calibration system applied in a geostationary orbit, as described in the foregoing embodiments, and its problem-solving principle is similar to that method. The electronic device provided in this application includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, which are executed by the at least one processor to enable the at least one processor to execute the methods and / or technical solutions of the various embodiments of this application described above.

[0113] The electronic device may be a microwave radiometer or other electronic device.

[0114] Figure 4 The diagram illustrates the structure of an apparatus suitable for implementing the methods and / or technical solutions in the embodiments of this application. The apparatus 1200 includes a Central Processing Unit (CPU) 1201, which can perform various appropriate actions and processes based on a program stored in a Read Only Memory (ROM) 1202 or a program loaded from a storage portion 1208 into a Random Access Memory (RAM) 1203. The RAM 1203 also stores various programs and data required for system operation. The CPU 1201, ROM 1202, and RAM 1203 are interconnected via a bus 1204. An Input / Output (I / O) interface 1205 is also connected to the bus 1204.

[0115] The following components are connected to I / O interface 1205: an input section 1206 including a keyboard, mouse, touchscreen, microphone, infrared sensor, etc.; an output section 1207 including a cathode ray tube (CRT), liquid crystal display (LCD), LED display, OLED display, etc., and speakers, etc.; a storage section 1208 including one or more computer-readable media such as hard disk, optical disk, magnetic disk, semiconductor memory, etc.; and a communication section 1209 including a network interface card such as a LAN (Local Area Network) card, modem, etc. The communication section 1209 performs communication processing via a network such as the Internet.

[0116] In particular, the methods and / or embodiments in this application can be implemented as computer software programs. For example, the embodiments disclosed in this application include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowchart. When the computer program is executed by the central processing unit (CPU) 1201, it performs the functions defined in the methods of this application.

[0117] Another embodiment of this application provides a computer-readable storage medium having computer program instructions stored thereon, which can be executed by a processor to implement the methods and / or technical solutions of any one or more embodiments of this application described above.

[0118] Specifically, this embodiment may employ any combination of one or more computer-readable media. A computer-readable medium may be a computer-readable signal medium or a computer-readable storage medium. A computer-readable storage medium may be, for example,—but not limited to—an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of computer-readable storage media (a non-exhaustive list) include: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this document, a computer-readable storage medium may be any tangible medium that contains or stores a program that can be used by or in connection with an instruction execution system, apparatus, or device.

[0119] Computer-readable signal media may include data signals propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals may take various forms, including—but not limited to—electromagnetic signals, optical signals, or any suitable combination thereof. Computer-readable signal media may also be any computer-readable medium other than computer-readable storage media, capable of sending, propagating, or transmitting programs for use by or in connection with an instruction execution system, apparatus, or device.

[0120] The program code contained on a computer-readable medium may be transmitted using any suitable medium, including—but not limited to—wireless, wire, optical fiber, RF, etc., or any suitable combination thereof.

[0121] Computer program code for performing the operations of this application can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0122] The flowcharts or block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of devices, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-specific system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0123] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0124] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or page components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection between devices or units through some interfaces, and may be electrical, mechanical, or other forms.

[0125] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0126] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or in a combination of hardware and software functional units.

[0127] The integrated units implemented as software functional units described above can be stored in a computer-readable storage medium. These software functional units, stored in a storage medium, include several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute some steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0128] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

[0129] Furthermore, it is clear that the word "comprising" does not exclude other units or steps, and the singular does not exclude the plural. Multiple units or devices recited in a device claim may also be implemented by a single unit or device through software or hardware. The terms "first," "second," etc., are used to indicate names and do not indicate any specific order.

Claims

1. A method for evaluating the on-orbit calibration error of a microwave radiometer calibration system used in geostationary orbit, wherein, The method includes: Step 1: Determine the brightness temperature of the calibration cold source based on the radiation transmission path of the calibration cold source in the microwave radiometer calibration system and the influencing factors of the calibration cold source. Step 2: Determine the error of the calibration cold source based on its brightness temperature; Step 3: Determine the brightness temperature of the calibration heat source based on the radiation transmission path of the calibration heat source in the microwave radiometer calibration system and the influencing factors of the calibration heat source; Step 4: Determine the error of the calibration heat source based on its brightness temperature; Step 5: Determine the brightness temperature of the Earth antenna target based on the radiation transmission path of the Earth radiation during Earth observation by the microwave radiometer calibration system and the influencing factors of the brightness temperature of the Earth antenna target. Step 6: Determine the error of the Earth observation radiation brightness temperature based on the Earth antenna target brightness temperature; Step 7: Based on the errors of the calibration cold source, the calibration heat source, the Earth observation radiation brightness temperature, and the Earth antenna target brightness temperature, the on-orbit calibration error of the microwave radiometer calibration system is evaluated using the following formula: ， in, This indicates the on-orbit calibration error of the microwave radiometer calibration system. This indicates that when both the calibration heat source and the calibration cold source have errors, the microwave radiometer includes the antenna brightness temperature of the Earth observations with errors. This indicates the brightness temperature of the Earth antenna target. This indicates the error of the calibration heat source. This indicates the error of the calibration cold source. This indicates the error in the observed Earth radiation brightness temperature. , , These represent the voltage count values ​​of the Earth antenna target, the voltage count values ​​of the calibration cold source, and the voltage count values ​​of the calibration heat source, respectively.

2. The on-orbit calibration error assessment method according to claim 1, wherein, The radiation transmission path of the calibration cold source is: cosmic background radiation → microwave radiometer cold space plane mirror → microwave radiometer quasi-optical network → microwave radiometer receiver. The influencing factors of the calibration cold source include at least one of the following: the brightness temperature of the cosmic background radiation received in the main lobe beam direction of the microwave radiometer cold space plane mirror, the equivalent side lobe beam brightness temperature of the microwave radiometer cold space plane mirror, and the self-radiation brightness temperature of the microwave radiometer cold space plane mirror. The methods for determining the brightness temperature of the calibration cold source include: The brightness temperature of the calibration cold source is determined by combining the following formula (1); ， in, This indicates the brightness temperature of the calibration cold source. The emissivity of the cold-air plane mirror of the microwave radiometer is given. The main lobe beam efficiency of the cold-air plane mirror of the microwave radiometer. , , These represent the brightness temperature of the cosmic background radiation, the equivalent sidelobe beam brightness temperature of the cold-space plane mirror of the microwave radiometer, and the physical temperature of the cold-space plane mirror of the microwave radiometer, respectively.

3. The on-orbit calibration error assessment method according to claim 2, wherein, The error of the calibration cold source is determined based on its brightness temperature, including: Pair each parameter in the formula (1) Taking the partial derivative, we obtain the following formula (2), which is used to determine the error of the calibration cold source: ， （2） in, This indicates the error of the calibration cold source. This indicates the emissivity error of the cold-air plane mirror of the microwave radiometer. This indicates the main lobe beam efficiency error of the cold-air plane mirror in the microwave radiometer. This represents the equivalent sidelobe beam brightness temperature error of the cold-air plane mirror of the microwave radiometer. This indicates the physical temperature measurement error of the cold air plane mirror of the microwave radiometer.

4. The on-orbit calibration error assessment method according to claim 3, wherein, The radiation transmission path of the calibration heat source is: calibration heat source blackbody → microwave radiometer quasi-optical network → microwave radiometer receiver. The influencing factors of the calibration heat source include at least one of the following: the heat source radiation brightness temperature of the calibration heat source blackbody and the equivalent sidelobe brightness temperature of the calibration heat source blackbody. The methods for determining the brightness temperature of the calibration heat source include: The brightness temperature of the calibration heat source is determined by combining the following formula (3): （3） in, This indicates the brightness temperature of the calibration heat source. , These represent the calibration source temperature and the equivalent sidelobe brightness temperature of the calibration heat source blackbody, respectively. The heat source main beam efficiency of the calibrated heat source blackbody, This represents the emissivity of the calibrated heat source blackbody.

5. The on-orbit calibration error assessment method according to claim 4, wherein determining the error of the calibration heat source based on the brightness temperature of the calibration heat source includes: Find the value of each parameter in the formula (3). Partial derivatives yield the following formula (4), which is used to determine the error of the calibration heat source according to formula (4): ， （4） in, This indicates the error of the calibration heat source. This indicates the main beam efficiency error of the calibrated blackbody heat source. This represents the equivalent sidelobe brightness temperature error of the calibrated thermal blackbody. This indicates the emissivity error of the calibration heat source blackbody. This indicates the temperature error of the calibrated heat source.

6. The on-orbit calibration error assessment method according to claim 5, wherein, The radiation transmission path of Earth's radiation during Earth observation by the microwave radiometer calibration system is as follows: Earth target → microwave radiometer main reflector → microwave radiometer sub reflector → microwave radiometer quasi-optical network → microwave radiometer receiver. The factors affecting the brightness temperature of the Earth antenna target include at least one of the following: the brightness temperature of the main lobe beam direction of the microwave radiometer main reflector is reflected by the microwave radiometer main reflector and the microwave radiometer sub reflector; the brightness temperature of the side lobe beam of the microwave radiometer main reflector is reflected by the microwave radiometer main reflector and the microwave radiometer sub reflector; the self-radiation brightness temperature of the microwave radiometer main reflector; and the self-radiation brightness temperature of the microwave radiometer sub reflector. The methods for determining the brightness temperature of the Earth antenna target include: The brightness temperature of the Earth target antenna is determined by combining the following formula (5): ， （5） in, This indicates the brightness temperature of the Earth antenna target. These represent the emissivity of the primary reflector and the emissivity of the secondary reflector of the microwave radiometer, respectively. The physical temperature of the primary reflector and the physical temperature of the secondary reflector of the microwave radiometer; The main lobe beam efficiency of the main and sub-reflector antennas of the microwave radiometer during Earth observation; The equivalent sidelobe beam brightness temperature of the main and secondary antenna reflectors of the microwave radiometer during Earth observation; Brightness temperature for Earth targets.

7. The on-orbit calibration error assessment method according to claim 6, wherein, Based on the brightness temperature of the Earth antenna target, the error in the Earth observation radiation brightness temperature is determined, including: Find the value of each parameter in the formula (5). Partial derivatives yield the following formula (6), which is used to determine the error of the Earth observation radiation brightness temperature according to formula (6): ， ， ， ， ， （6） in, This indicates the error in the observed Earth radiation brightness temperature. This indicates the emissivity error of the primary reflector of the microwave radiometer. This indicates the emissivity error of the sub-reflector of the microwave radiometer. This indicates the main lobe beam efficiency error of the reflector antenna during Earth observation. This represents the equivalent sidelobe beam brightness temperature error of the antenna reflector during Earth observation. This indicates the physical temperature error of the primary reflector of the microwave radiometer. This indicates the physical temperature error of the sub-reflector of the microwave radiometer.

8. The on-orbit calibration error assessment method according to claim 7, wherein, The method also includes: Based on the calibration principle of microwave radiometers, a calibration equation for the microwave radiometer is established, and the calibration equation for the brightness temperature of the Earth target antenna is obtained: ， （7） in, , , These represent the brightness temperature of the Earth target antenna, the brightness temperature of the calibration cold source, and the brightness temperature of the calibration heat source, respectively. , , These represent the voltage count values ​​of the Earth antenna target, the voltage count values ​​of the calibration cold source, and the voltage count values ​​of the calibration heat source, respectively.

9. According to the on-orbit calibration error assessment method of claim 8, if there are errors in the brightness temperature of the calibration heat source, the brightness temperature of the calibration cold source, and the brightness temperature of the Earth antenna target, the calibration equation (7) can be written as: ， （8） in, and These represent the brightness temperatures of the calibration heat source and the calibration cold source when errors exist, respectively. This indicates that when both the calibration heat source and the calibration cold source have errors, the microwave radiometer includes the antenna brightness temperature of the Earth observation with errors.

10. An on-orbit calibration error assessment device for a microwave radiometer calibration system used in geostationary orbit, the device implementing the method as described in any one of claims 1 to 9, wherein, The device includes: The first determining module is used to determine the brightness temperature of the calibration cold source based on the radiation transmission path of the calibration cold source in the microwave radiometer calibration system and the influencing factors of the calibration cold source. The second determining module is used to determine the error of the calibration cold source based on the brightness temperature of the calibration cold source; The third determining module is used to determine the brightness temperature of the calibration heat source by considering the radiation transmission path of the calibration heat source and the influencing factors of the calibration heat source in the microwave radiometer calibration system. The fourth determining module is used to determine the error of the calibration heat source based on the brightness temperature of the calibration heat source; The fifth determining module is used to determine the brightness temperature of the Earth antenna target based on the radiation transmission path of the Earth's radiation during Earth observation by the microwave radiometer calibration system and the influencing factors of the brightness temperature of the Earth antenna target. The sixth determining module is used to determine the error of the Earth observation radiation brightness temperature based on the brightness temperature of the Earth antenna target; The evaluation module is used to evaluate the on-orbit calibration error of the microwave radiometer calibration system based on the errors of the calibration cold source, the calibration heat source, the Earth observation radiation brightness temperature, and the Earth antenna target brightness temperature, using the following formula: ， in, This indicates the on-orbit calibration error of the microwave radiometer calibration system. This indicates that when both the calibration heat source and the calibration cold source have errors, the microwave radiometer includes the antenna brightness temperature of the Earth observations with errors. This indicates the brightness temperature of the Earth antenna target. This indicates the error of the calibration heat source. This indicates the error of the calibration cold source. This indicates the error in the observed Earth radiation brightness temperature. , , These represent the voltage count values ​​of the Earth antenna target, the voltage count values ​​of the calibration cold source, and the voltage count values ​​of the calibration heat source, respectively.

11. An electronic device, the electronic device comprising: At least one processor; as well as A memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor to enable the at least one processor to perform the method of any one of claims 1 to 9.

12. A computer-readable storage medium having stored thereon computer program instructions that can be executed by a processor to implement the method as described in any one of claims 1 to 9.

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