On-orbit calibration precision evaluation method for stationary orbit microwave radiometer calibration system

Abstract

The invention provides an in-orbit calibration error evaluation method and device for a microwave radiometer calibration system applied to a stationary orbit and a computer readable storage medium. According to the method, the error of a calibration cold source, the error of a calibration heat source, the error of earth observation radiation brightness temperature and the brightness temperature of an earth target are determined; the on-orbit calibration error of the microwave radiometer calibration system is evaluated based on the on-orbit calibration error of the microwave radiometer calibration system, the error of a calibration cold source, the error of a calibration heat source, the error of earth observation radiation brightness temperature and the earth target brightness temperature in the microwave radiometer calibration system applied in a stationary orbit are evaluated respectively, namely, all the errors are quantified, and the on-orbit calibration error of the microwave radiometer calibration system is evaluated. According to the method, the on-orbit calibration error of the microwave radiometer calibration system is quantified, and different radiation transmission paths are also considered in the process of evaluating each error, so that the evaluation of the source of the on-orbit calibration error of the microwave radiometer calibration system applied in the stationary orbit is effective and accurate, and the method has the characteristic of high implementation.

Description

Technical Field

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

[0002] This section is intended to provide a background or context to the embodiments of the application that are recited in the claims. The description herein is not admitted to be prior art by inclusion in this section.

[0003] Microwaves can penetrate the cloud and rain atmosphere very well to achieve all-day and all-weather observations. At the same time, clouds, rain and atmospheric media affect the transmission of microwave radiation in the atmosphere by absorbing, emitting and scattering microwaves. The absorption, emission and scattering of microwaves by clouds, rain and atmospheric media are related to the thermal structure of the atmosphere and the microscopic and macroscopic physical properties of clouds and rain. Based on this, the use of microwave payload detection data can invert the thermal structure and physical properties of cloud and rain atmosphere, which is one of the important tools for atmospheric observation.

[0004] Geostationary microwave radiometer technology is an important technology of geostationary microwave meteorological satellites. The long revisit period of polar-orbiting satellites limits the application of polar-orbiting meteorological satellite observation data in the monitoring and early warning of short-term and rapidly developing disastrous weather. Even if polar-orbiting satellites are networked for observation, it is still difficult to fully meet the weather forecast's observation needs for instantaneous and variable atmospheric humidity, thermal conditions, heavy rains, severe convection and other disastrous weather. In the face of these rapidly developing and high-temporal-resolution disastrous weather phenomena and processes, monitoring can only be achieved through geostationary meteorological satellites. Geostationary satellites have great advantages in observation field and temporal resolution. Equipped with microwave remote sensing instruments on the platform of geostationary satellites, the temporal resolution of observations can be effectively improved, the detection capability of meteorological satellites for clouds and rain atmosphere can be improved, a large area of ​​the earth can be covered in a short time, and high-frequency observation data can be provided.

[0005] With the growing demand for passive microwave remote sensing technology and meteorological applications, microwave radiometers are facing increasingly higher requirements for accuracy and temporal and spatial resolution. Developing geostationary orbit atmospheric microwave detection technology and realizing all-weather and all-day observation of the earth can effectively improve the accuracy of weather forecasts. Geostationary orbit microwave radiometers use the principle of passive microwave remote sensing to perform multi-dimensional detection of atmospheric parameters such as atmospheric temperature profiles, humidity profiles, precipitation, and clouds. Microwave radiometers are passive receiving systems consisting of antennas and receivers. The on-orbit calibration of geostationary orbit microwave radiometers generally adopts a two-point calibration method. According to the system design of the microwave radiometer itself, the blackbody calibration source and cold air are used as hot calibration sources and cold calibration sources respectively, and the functional relationship between the blackbody calibration source test voltage and the cold air test voltage and the hot calibration source brightness temperature and the cold air brightness temperature is established, and the target observation voltage is converted into the target observation brightness temperature. The calibration accuracy of microwave radiometers is a key factor affecting the quantitative application of their observation data. The realization of on-orbit calibration accuracy assessment can strongly support the quantitative scientific application of geostationary orbit microwave observation data. Summary of the invention

[0006] Multiple aspects of the present application provide an on-orbit calibration error assessment method, device and computer-readable storage medium for a microwave radiometer calibration system used in a geostationary orbit, so as to implement an assessment of the on-orbit calibration accuracy of a geostationary orbit microwave radiometer.

[0007] In one aspect of the present application, a method for evaluating an on-orbit calibration error of a microwave radiometer calibration system used in a geostationary orbit is provided, wherein the method comprises:

[0008] Step 1, determining the brightness temperature of the calibration cold source according to 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, determining the error of the calibration cold source according to the brightness temperature of the calibration cold source;

[0010] Step 3, determining the brightness temperature of the calibration heat source according to 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, determining the error of the calibration heat source according to the brightness temperature of the calibration heat source;

[0012] Step 5, determining the brightness temperature of the earth antenna target according to the radiation transmission path of the earth radiation during the earth observation by the microwave radiometer calibration system and the influencing factors of the brightness temperature of the earth antenna target;

[0013] Step 6, determining the error of the Earth observation radiation brightness temperature according to the Earth antenna target brightness temperature;

[0014] Step 7, evaluating the on-orbit calibration error of the microwave radiometer calibration system according to the error of the calibration cold source, the error of the calibration hot source, the error of the earth observation radiation brightness temperature, and the earth target brightness temperature.

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

[0016] A first determination module is used to determine the brightness temperature of the calibration cold source according to 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] A second determination module, used to determine the error of the calibration cold source according to the brightness temperature of the calibration cold source;

[0018] A third determination module is used to determine the brightness temperature of a calibration heat source based on 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] A fourth determination module, configured to determine an error of the calibration heat source according to the brightness temperature of the calibration heat source;

[0020] A fifth determination module, configured to determine the brightness temperature of the earth antenna target according to 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;

[0021] A sixth determination module, configured to determine an error of the earth observation radiation brightness temperature according to the earth antenna target brightness temperature;

[0022] An evaluation module is used to evaluate the on-orbit calibration error of the microwave radiometer calibration system according to the error of the calibration cold source, the error of the calibration hot source, the error of the earth observation radiation brightness temperature, and the earth target brightness temperature.

[0023] Another aspect of the present application provides an electronic device, including:

[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, and the instructions are executed by the at least one processor so that the at least one processor can execute the on-orbit calibration error evaluation method for a microwave radiometer calibration system used in a geostationary orbit as described above.

[0027] In another aspect of the present application, a computer-readable storage medium is provided, on which computer program instructions are stored. The computer program instructions can be executed by a processor to implement an on-orbit calibration error assessment method for a microwave radiometer calibration system used in a geostationary orbit.

[0028] An embodiment of the present application provides an on-orbit calibration error evaluation method for a microwave radiometer calibration system used in a geostationary orbit. The method determines the error of a calibration cold source, the error of a calibration heat source, the error of the brightness temperature of earth observation radiation, and the brightness temperature of an earth target, and evaluates the on-orbit calibration error of the microwave radiometer calibration system based on the error. That is, by adopting an error analysis method, the error of a calibration cold source, the error of a calibration heat source, the error of the brightness temperature of earth observation radiation, and the brightness temperature of an earth target in the microwave radiometer calibration system used in the geostationary orbit are evaluated respectively, that is, each error is quantified, thereby also quantifying the on-orbit calibration error of the microwave radiometer calibration system. In addition, in the process of evaluating each error, different radiation transmission paths are also taken into account, so that the evaluation of the source of the on-orbit calibration error of the microwave radiometer calibration system used in the geostationary orbit is not only effective and accurate, but also provides a scientific basis for improving the calibration design scheme of future geostationary orbit instruments, and also provides a scientific basis for the quantitative use of geostationary orbit microwave observation data, and has the characteristics of strong feasibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

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

[0031] Figure 1 A schematic flow chart of an on-orbit calibration error evaluation method for a microwave radiometer calibration system used in a geostationary orbit provided in one embodiment of the present application;

[0032] Figure 2 A schematic diagram showing various radiation transmission optical paths in a microwave radiometer calibration system used in a geostationary orbit according to an embodiment of the present application;

[0033] Figure 2 (a) shows a schematic diagram of the radiation transmission optical path of the earth radiation of the microwave radiometer calibration system during earth observation;

[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 of an on-orbit calibration error assessment device of a microwave radiometer calibration system used in a geostationary orbit provided by another embodiment of the present application;

[0037] Figure 4 The present invention is a schematic diagram of the structure of an electronic device suitable for implementing the solution in the embodiment of the present application.

[0038] The same or similar reference numerals in the drawings represent the same or similar components. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0040] In a typical configuration of the present application, the terminal and the equipment of the service network each include one or more processors (CPU), input / output interface, network interface and memory.

[0041] The memory may include non-permanent storage in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0042] Computer readable media include permanent and non-permanent, removable and non-removable media, and can be implemented by any method or technology to store information. Information can be computer program instructions, data structures, modules of programs 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 technology, read-only compact disk (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device.

[0043] The embodiment of the present application provides an on-orbit calibration error evaluation method for a microwave radiometer calibration system used in a geostationary orbit, wherein the method comprises:

[0044] Step 1, determining the brightness temperature of the calibration cold source according to 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, determining the error of the calibration cold source according to the brightness temperature of the calibration cold source;

[0046] Step 3, determining the brightness temperature of the calibration heat source according to 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, determining the error of the calibration heat source according to the brightness temperature of the calibration heat source;

[0048] Step 5, determining the brightness temperature of the earth antenna target according to the radiation transmission path of the earth radiation during the earth observation by the microwave radiometer calibration system and the influencing factors of the brightness temperature of the earth antenna target;

[0049] Step 6, determining the error of the Earth observation radiation brightness temperature according to the Earth antenna target brightness temperature;

[0050] Step 7, evaluating the on-orbit calibration error of the microwave radiometer calibration system according to the error of the calibration cold source, the error of the calibration hot source, the error of the earth observation radiation brightness temperature, and the earth target brightness temperature.

[0051] In actual scenarios, the execution subject of the 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 a device formed by integrating the microwave radiometer with other electronic devices. Here, the computing device or data processing device includes but is not limited to an electronic device that can automatically perform 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), field-programmable gate arrays (FPGAs), digital signal processors (DSPs), embedded devices, etc.

[0052] Figure 1 The flowchart of an on-orbit calibration error evaluation method of a microwave radiometer calibration system applied in a geostationary orbit provided by an embodiment of the present application is shown. It should be noted that step 1, step 2, step 3, step 4, step 5, step 6 and step 7 in the text are not figure marks. Specifically, the method includes:

[0053] Step 1, determining the brightness temperature of the calibration cold source according to 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, determining the error of the calibration cold source according to the brightness temperature of the calibration cold source;

[0055] Step 3, determining the brightness temperature of the calibration heat source according to 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, determining the error of the calibration heat source according to the brightness temperature of the calibration heat source;

[0057] Step 5, determining the brightness temperature of the earth antenna target according to the radiation transmission path of the earth radiation during the earth observation by the microwave radiometer calibration system and the influencing factors of the brightness temperature of the earth antenna target;

[0058] Step 6, determining the error of the Earth observation radiation brightness temperature according to the Earth antenna target brightness temperature;

[0059] Step 7, evaluating the on-orbit calibration error of the microwave radiometer calibration system according to the error of the calibration cold source, the error of the calibration hot source, the error of the earth observation radiation brightness temperature, and the earth target brightness temperature.

[0060] Specifically, in step 1, the brightness temperature of the calibration cold source is determined according to 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 an on-orbit microwave radiometer, it usually 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 background radiation refers to the isotropic microwave radiation from the background of cosmic space, also known as microwave background radiation. Microwave radiometer cold space plane mirror refers to the plane mirror used in the microwave radiometer calibration system to reflect cold space radiation. Microwave radiometer quasi-optical network (QON) refers to the quasi-optical feeding network used in the microwave radiometer calibration system. Microwave radiometer receiver refers to a receiver that receives microwave radiation.

[0063] Here, the influencing factors of the calibration cold source include at least any 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.

[0064] Here, the method of determining the brightness temperature of the calibration cold source includes:

[0065] Combined with the following formula (1), the brightness temperature of the calibration cold source is determined;

[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 represents the brightness temperature of the calibration cold source, α C is the emissivity of the cold plane mirror of the microwave radiometer, η C is the main lobe beam efficiency of the cold plane mirror of the microwave radiometer, T Cos 、T CE 、T C0 They respectively 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.

[0068] Here, it should be noted that in the 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), and 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 the microwave radiometer cold space plane mirror refers to the ratio of the power radiated by the main lobe beam of the microwave radiometer cold space plane mirror to the total power radiated by the total beam of the microwave radiometer 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 the microwave radiometer cold space plane mirror refers to the brightness temperature received by the side lobes or side lobes other than the main lobe.

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

[0070] Step 2: determining the error of the calibration cold source according to the brightness temperature of the calibration cold source.

[0071] Specifically, each parameter in the above formula (1) is C The partial derivative is obtained to obtain the following formula (2), and then the error of the calibration cold source is determined according to formula (2):

[0072]

[0073] Among them, δT C represents the error of the calibration cold source, δα C represents the emissivity error of the cold-air plane mirror of the microwave radiometer, δη C represents the main lobe beam efficiency error of the microwave radiometer cold plane mirror, δT CE represents the equivalent sidelobe beam brightness temperature error of the cold space plane mirror of the microwave radiometer, δT C0 It represents the physical temperature measurement error of the cold air plane mirror of the microwave radiometer.

[0074] Step 3: determining the brightness temperature of the calibration heat source according to 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 may be a calibration heat source black body. The radiation transmission path of the calibration heat source is: calibration heat source black body → 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 black body and the equivalent sidelobe brightness temperature of the calibration heat source black body. Figure 2(c) in the figure shows a schematic diagram of the radiation transmission optical path of the calibration heat source in the microwave radiometer calibration system.

[0076] The heat source radiation brightness temperature of the calibration heat source black body refers to the brightness temperature radiated by the heat source black body. The equivalent side lobe brightness temperature of the calibration heat source black body refers to the equivalent brightness temperature radiated outward by the side lobe of the heat source black body.

[0077] Here, the method of determining the brightness temperature of the calibration heat source includes:

[0078] Combined with the following formula (3), the brightness temperature of the calibration heat source is determined:

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

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

[0081] Step 4: Determine the error of the calibration heat source according to the brightness temperature of the calibration heat source, such as calculating T for each parameter in formula (3). H Partial derivative, the following formula (4) is obtained to determine the error of the calibration heat source according to formula (4):

[0082]

[0083] Among them, δT H represents the error of the calibration heat source, δη H represents the heat source main beam efficiency error of the calibration heat source blackbody, δT HE represents the equivalent sidelobe brightness temperature error of the calibration heat source blackbody, δε represents the emissivity error of the calibration heat source blackbody, δT Hotload Represents the temperature error of the calibration heat source.

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

[0085] The radiation transmission path of the earth radiation of the microwave radiometer calibration system during earth observation is: earth target→microwave radiometer main reflection surface→microwave radiometer secondary reflection surface→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) in the figure shows a schematic diagram of the radiation transmission optical path of the earth radiation during earth observation by the microwave radiometer calibration system.

[0086] The influencing factors of the brightness temperature of the earth antenna target include at least any one of the following: the brightness temperature in the main lobe beam direction of the main reflection surface of the microwave radiometer is reflected by the main reflection surface of the microwave radiometer and the sub-reflection surface of the microwave radiometer, and the side lobe beam brightness temperature of the main reflection surface of the microwave radiometer is reflected by the main reflection surface of the microwave radiometer and the sub-reflection surface of the microwave radiometer; the self-radiation brightness temperature of the main reflection surface of the microwave radiometer, and the self-radiation brightness temperature of the sub-reflection surface of the microwave radiometer.

[0087] Wherein, the method of determining the brightness temperature of the earth antenna target includes:

[0088] Combined with the following formula (5), the brightness temperature of the earth target antenna is determined:

[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 represents the Earth antenna target brightness temperature, α M , α S They represent the emissivity of the main reflective surface of the microwave radiometer and the emissivity of the secondary reflective surface of the microwave radiometer respectively; T M0 , T S0 Respectively represent the physical temperature of the main reflecting surface of the microwave radiometer and the physical temperature of the secondary reflecting surface of the microwave radiometer; η A is the main lobe beam efficiency of the main and sub-reflector antennas of the microwave radiometer during earth observation; T AE is the equivalent sidelobe beam brightness temperature of the main and auxiliary antenna reflectors of the microwave radiometer during earth observation; T B is the Earth's target brightness temperature.

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

[0094] Each parameter in the formula (5) is calculated H Partial derivative, the following formula (6) is obtained to determine the error of the Earth observation radiation brightness temperature according to formula (6):

[0095]

[0096] Among them, δT A represents the error of the Earth observation radiation brightness temperature, δα M Denotes the emissivity error of the main reflective surface of the microwave radiometer, δα S represents the emissivity error of the microwave radiometer sub-reflector, δη A represents the main lobe beam efficiency error of the reflector antenna during earth observation, δT AE It represents the equivalent sidelobe beam brightness temperature error of the antenna reflector during earth observation, δT M0 Represents the physical temperature error of the main reflector surface of the microwave radiometer, δT S0 Represents the physical temperature error of the microwave radiometer sub-reflector.

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

[0098] According to the calibration principle of the microwave radiometer, the calibration equation of the microwave radiometer is established to obtain the calibration equation of the brightness temperature of the earth target antenna:

[0099]

[0100] Among them, T A 、T C 、T H Respectively represent the brightness temperature of the earth target antenna, the brightness temperature of the calibration cold source, and the brightness temperature of the calibration hot source, V A 、V C 、V H They respectively represent the voltage count value of the earth antenna target, the voltage count value of the calibration cold source, and the voltage count value of the calibration hot source.

[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 They represent the brightness temperature of the calibrated hot source and the brightness temperature of the calibrated cold source respectively when there is an error, T′A It indicates that when both the calibration hot source and the calibration cold source have errors, the antenna brightness temperature of the earth observation of the microwave radiometer contains errors.

[0104] Step 7, evaluating the on-orbit calibration error of the microwave radiometer calibration system according to the error of the calibration cold source, the error of the calibration hot source, the error of the Earth observation radiation brightness temperature, and the Earth target brightness temperature. Specifically, the on-orbit calibration error of the microwave radiometer calibration system is evaluated by combining the following formula (9):

[0105]

[0106] Among them, δT ∑ represents the on-orbit calibration error of the microwave radiometer calibration system.

[0107] Here, it should be noted that, in a specific embodiment, step 1, step 3 and step 5 can be executed in parallel or in series; step 2, step 4 and step 6 can be executed in parallel or in series.

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

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

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

[0111] The embodiments of the above modules are the same or basically similar to the embodiments of the corresponding steps in the aforementioned on-orbit calibration error assessment method of a microwave radiometer calibration system used in a geostationary orbit. For the sake of brevity, they are not repeated here and are included here by reference.

[0112] Based on the same inventive concept, an electronic device is also provided in an embodiment of the present application, and the method corresponding to the electronic device may be an on-orbit calibration error assessment method of a microwave radiometer calibration system used in a geostationary orbit in the aforementioned embodiment, and its principle of solving the problem is similar to that of the method. The electronic device provided in an embodiment of the present 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, and the instructions are executed by the at least one processor so that the at least one processor can execute the methods and / or technical solutions of the aforementioned multiple embodiments of the present application.

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

[0114] Figure 4 The structure of a device suitable for implementing the method and / or technical solution in the embodiment of the present application is shown, and the device 1200 includes a central processing unit (CPU, Central Processing Unit) 1201, which can perform various appropriate actions and processes according to the program stored in the read-only memory (ROM, Read Only Memory) 1202 or the program loaded from the storage part 1208 to the random access memory (RAM, Random Access Memory) 1203. In RAM1203, various programs and data required for system operation are also stored. CPU 1201, ROM 1202 and RAM 1203 are connected to each other through bus 1204. Input / output (I / O, Input / Output) interface 1205 is also connected to bus 1204.

[0115] The following components are connected to the I / O interface 1205: an input section 1206 including a keyboard, a mouse, a touch screen, a microphone, an infrared sensor, etc.; an output section 1207 including a cathode ray tube (CRT), a liquid crystal display (LCD), an LED display, an OLED display, etc., and a speaker, etc.; a storage section 1208 including one or more computer-readable media such as a hard disk, an optical disk, a magnetic disk, a semiconductor memory, etc.; and a communication section 1209 including a network interface card such as a LAN (Local Area Network) card, a 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 the embodiments of the present application may be implemented as computer software programs. For example, the embodiments disclosed in the present application include a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program includes program code for executing the method shown in the flowchart. When the computer program is executed by the central processing unit (CPU) 1201, the above functions defined in the method of the present application are executed.

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

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

[0119] Computer readable signal media may include a data signal propagated in baseband or as part of a carrier wave, which carries a computer readable program code. Such propagated data signals may take a variety of forms, including, but not limited to, electromagnetic signals, optical signals, or any suitable combination of the above. Computer readable signal media may also be any computer readable medium other than a computer readable storage medium, which may send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, apparatus, or device.

[0120] Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

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

[0122] The flow chart or block diagram in the accompanying drawings shows the possible architecture, function and operation of the equipment, method and computer program product according to various embodiments of the present application. In this regard, each square box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some implementations as replacements, the functions marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two square boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be implemented with a dedicated system for hardware that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

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

[0124] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or page components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

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

[0126] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of hardware plus software functional units.

[0127] The above-mentioned integrated unit implemented in the form of a software functional unit can be stored in a computer-readable storage medium. The above-mentioned software functional unit is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor to perform some steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (Read-Only Memory, ROM), random access memory (Random Access Memory, RAM), disk or optical disk and other media that can store program codes.

[0128] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

[0129] In addition, 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 stated in a device claim can also be implemented by one unit or device through software or hardware. The words first, second, etc. are used to indicate names, and do not indicate any particular order.

Claims

1. An on-orbit calibration error evaluation method for a microwave radiometer calibration system used in a geostationary orbit, wherein: The method includes: Step 1, determining the brightness temperature of the calibration cold source according to 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, determining the error of the calibration cold source according to the brightness temperature of the calibration cold source; Step 3, determining the brightness temperature of the calibration heat source according to 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, determining the error of the calibration heat source according to the brightness temperature of the calibration heat source; Step 5, determining the brightness temperature of the earth antenna target according to the radiation transmission path of the earth radiation during the earth observation by the microwave radiometer calibration system and the influencing factors of the brightness temperature of the earth antenna target; Step 6, determining the error of the Earth observation radiation brightness temperature according to the Earth antenna target brightness temperature; Step 7, evaluating the on-orbit calibration error of the microwave radiometer calibration system according to the error of the calibration cold source, the error of the calibration hot source, the error of the earth observation radiation brightness temperature, and the earth target brightness temperature.

2. The on-orbit calibration error evaluation 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, and 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; Wherein, the method of determining the brightness temperature of the calibration cold source includes: Combined with the following formula (1), the brightness temperature of the calibration cold source is determined; T C =(1-a C )[or C T Cos +(1-th C )T CE ]+a C T C0 (1) Among them, T C represents the brightness temperature of the calibration cold source, α C is the emissivity of the cold plane mirror of the microwave radiometer, η C is the main lobe beam efficiency of the cold plane mirror of the microwave radiometer, T Cos , T CE , T C0 They respectively 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.

3. The on-orbit calibration error evaluation method according to claim 2, wherein: Determining the error of the calibration cold source according to the brightness temperature of the calibration cold source includes: Each parameter in the formula (1) is C By taking partial derivatives, the following formula (2) is obtained, so as to determine the error of the calibration cold source according to formula (2): Among them, δT C represents the error of the calibration cold source, δα C represents the emissivity error of the cold-air plane mirror of the microwave radiometer, δη C represents the main lobe beam efficiency error of the microwave radiometer cold plane mirror, δT CE represents the equivalent sidelobe beam brightness temperature error of the cold space plane mirror of the microwave radiometer, δT C0 It represents the physical temperature measurement error of the cold air plane mirror of the microwave radiometer.

4. The on-orbit calibration error evaluation method according to claim 3, wherein: The radiation transmission path of the calibration heat source is: calibration heat source black body → microwave radiometer quasi-optical network → microwave radiometer receiver, and 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 black body and the equivalent side lobe brightness temperature of the calibration heat source black body; Wherein, the method of determining the brightness temperature of the calibration heat source includes: Combined with the following formula (3), the brightness temperature of the calibration heat source is determined: T H =the H eT Hotload +(1-th H )T HE (3) Among them, T H represents the brightness temperature of the calibration heat source, T Hotload , T HE denote the calibration source temperature of the calibration heat source blackbody and the equivalent sidelobe brightness temperature of the calibration heat source blackbody, η H is the heat source main beam efficiency of the calibration heat source blackbody, and ε represents the emissivity of the calibration heat source blackbody.

5. The on-orbit calibration error assessment method according to claim 4, determining the error of the calibration heat source according to the brightness temperature of the calibration heat source, comprising: Each parameter in the formula (3) is calculated H Partial derivative, the following formula (4) is obtained to determine the error of the calibration heat source according to formula (4): Among them, δT H represents the error of the calibration heat source, δη H represents the heat source main beam efficiency error of the calibration heat source blackbody, δT HE represents the equivalent sidelobe brightness temperature error of the calibration heat source blackbody, δε represents the emissivity error of the calibration heat source blackbody, δT Hotlo Represents the temperature error of the calibration heat source.

6. The on-orbit calibration error evaluation method according to claim 5, wherein: The radiation transmission path of the earth radiation of the microwave radiometer calibration system during earth observation is: earth target → microwave radiometer main reflection surface → microwave radiometer sub-reflection surface → microwave radiometer quasi-optical network → microwave radiometer receiver, and the influencing factors of the earth antenna target brightness temperature include at least one of the following: the main lobe beam direction brightness temperature of the microwave radiometer main reflection surface is reflected by the microwave radiometer main reflection surface and the microwave radiometer sub-reflection surface, the side lobe beam brightness temperature of the microwave radiometer main reflection surface is reflected by the microwave radiometer main reflection surface and the microwave radiometer sub-reflection surface; the self-radiation brightness temperature of the microwave radiometer main reflection surface, the self-radiation brightness temperature of the microwave radiometer sub-reflection surface; Wherein, the method of determining the brightness temperature of the earth antenna target includes: Combined with the following formula (5), the brightness temperature of the earth target antenna is determined: T A =(1-a M (1-a) S )[or A T B +(1-th A )T AE ]+a M (1-a S )T M0 +a s T S0 (5) Among them, T A represents the Earth antenna target brightness temperature, α M , α S They represent the emissivity of the main reflective surface of the microwave radiometer and the emissivity of the secondary reflective surface of the microwave radiometer respectively; T M0 , T S0 Respectively represent the physical temperature of the main reflecting surface of the microwave radiometer and the physical temperature of the secondary reflecting surface of the microwave radiometer; η A is the main lobe beam efficiency of the main and sub-reflector antennas of the microwave radiometer during earth observation; T AE is the equivalent sidelobe beam brightness temperature of the main and auxiliary antenna reflectors of the microwave radiometer during earth observation; T B is the Earth's target brightness temperature.

7. The on-orbit calibration error assessment method according to claim 6, wherein: Determining the error of the earth observation radiation brightness temperature according to the earth antenna target brightness temperature, including: Each parameter in the formula (5) is calculated H Partial derivative, the following formula (6) is obtained to determine the error of the Earth observation radiation brightness temperature according to formula (6): Among them, δT A represents the error of the Earth observation radiation brightness temperature, δα M Denotes the emissivity error of the main reflective surface of the microwave radiometer, δα S represents the emissivity error of the microwave radiometer sub-reflector, δη A represents the main lobe beam efficiency error of the reflector antenna during earth observation, δT AE It represents the equivalent sidelobe beam brightness temperature error of the antenna reflector during earth observation, δT M0 Represents the physical temperature error of the main reflector surface of the microwave radiometer, δT S0 Represents the physical temperature error of the microwave radiometer sub-reflector.

8. The on-orbit calibration error evaluation method according to claim 7, wherein: The method further includes: According to the calibration principle of the microwave radiometer, the calibration equation of the microwave radiometer is established to obtain the calibration equation of the brightness temperature of the earth target antenna: Among them, T A , T C , T H Respectively represent the brightness temperature of the earth target antenna, the brightness temperature of the calibration cold source, and the brightness temperature of the calibration hot source, V A 、V C 、V H They respectively represent the voltage count value of the earth antenna target, the voltage count value of the calibration cold source, and the voltage count value of the calibration hot source.

9. According to the on-orbit calibration error evaluation 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: in, T′ H and T′ C They represent the brightness temperature of the calibrated hot source and the brightness temperature of the calibrated cold source respectively when there is an error, T′ A It indicates that when both the calibration hot source and the calibration cold source have errors, the antenna brightness temperature of the earth observation of the microwave radiometer contains errors.

10. The on-orbit calibration error evaluation method according to claim 9, wherein: According to the error of the calibration cold source, the error of the calibration hot source, the error of the Earth observation radiation brightness temperature, and the Earth target brightness temperature, the on-orbit calibration error of the microwave radiometer calibration system is evaluated in combination with the following formula (9): Among them, δT ∑ represents the on-orbit calibration error of the microwave radiometer calibration system.

11. An on-orbit calibration error assessment device for a microwave radiometer calibration system used in a geostationary orbit, wherein: The equipment includes: A first determination module is used to determine the brightness temperature of the calibration cold source according to the radiation transmission path of the calibration cold source in the microwave radiometer calibration system and the influencing factors of the calibration cold source; A second determination module, used to determine the error of the calibration cold source according to the brightness temperature of the calibration cold source; A third determination module is used to determine the brightness temperature of a 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; A fourth determination module, configured to determine an error of the calibration heat source according to the brightness temperature of the calibration heat source; A fifth determination module, configured to determine the brightness temperature of the earth antenna target according to 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; A sixth determination module, configured to determine an error of the Earth observation radiation brightness temperature according to the Earth antenna target brightness temperature; An evaluation module is used to evaluate the on-orbit calibration error of the microwave radiometer calibration system according to the error of the calibration cold source, the error of the calibration hot source, the error of the earth observation radiation brightness temperature, and the earth target brightness temperature.

12. An 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, and the instructions are executed by the at least one processor to enable the at least one processor to perform the method according to any one of claims 1 to 10.

13. A computer-readable storage medium having computer program instructions stored thereon, wherein the computer program instructions can be executed by a processor to implement the method according to any one of claims 1 to 10.

Images