Brightness temperature calibration heat source for satellite-borne millimeter wave and submillimeter wave detector

Abstract

The invention relates to the technical field of microwave remote sensing, in particular to a satellite-borne millimeter wave and submillimeter wave detector brightness temperature calibration heat source which comprises a metal shell, a radiation base body, a temperature measurement resistor, a heater, a heat insulation ring, a cover plate and an electric connector. The number of the temperature measuring resistors is multiple, and the multiple temperature measuring resistors are all arranged in the radiation substrate. The heater is adhered to the back surface of the radiation substrate; the cover plate is fixed at the bottom of the metal shell; the heat insulation ring is arranged in the metal shell and located between the heater and the cover plate. And the electric connector is a low-frequency electric connector, is arranged on the outer wall of the metal shell and is electrically connected with the temperature measuring resistor and the heater respectively. On the basis of meeting electromagnetic interference prevention, the influence of heat leakage caused by heat transfer between the radiation substrate and the shell on the temperature uniformity of the radiation surface is effectively reduced, and the uniformity of the radiation surface is greatly improved.

Description

Technical Field

[0001] The present application relates to the field of microwave remote sensing technology, and in particular to a brightness temperature calibration heat source for satellite-borne millimeter-wave and submillimeter-wave detectors. Background Art

[0002] In order to improve the accuracy of microwave remote sensing detection and realize quantitative remote sensing applications, it is necessary to calibrate the microwave radiometer in real time to eliminate the drift of its output with temperature and time. As a key single-unit equipment for calibration of satellite-borne microwave radiometers, the heat source needs to provide accurate standard radiation brightness temperature for the microwave radiometer. According to the radiation brightness temperature formula: T b =T h .ε+T g .(1-ε), the heat source should have ultra-high emissivity and ultra-high temperature uniformity, which can be approximated as a black body.

[0003] In order to simulate the blackbody characteristics as much as possible, a periodic array of metal bare (corner) cone structures based on overall processing is generally used. A radiator is formed by coating a certain thickness of high attenuation thermal conductive and wave-absorbing coating on the surface of the cone, taking into account the requirements of high emissivity and high temperature uniformity.

[0004] However, with the improvement of meteorological satellite calibration accuracy in recent years, the application orbit environment is complex, and the temperature range of the heat source is drastic (-130℃~+130℃). The calibration heat source based on the above design has the following shortcomings: atomic oxygen irradiation in the low-orbit environment causes erosion of the absorbing coating, affecting the internal structure of the coating and causing uncertainty in the emissivity; the flexible film heater is directly adhered to the back of the radiator with a curing adhesive. During the drastic change of the heat source temperature, the heater is at risk of being pulled and broken. When the extension displacement of the back of the radiator is greater than the tensile strength of the heater, the constantan wire of the heater breaks; when working in orbit, the metal casing can effectively shield electromagnetic interference, but the heat exchange between the casing and the radiator is intense, and there is a risk of heat leakage, which affects the temperature unevenness of the radiating surface; after the multi-channel temperature measuring resistor leads inside the corner cone are "bundled", they are led out through the "wire slot" designed on the back of the radiating substrate, causing uneven heating of the wire harness, which has a certain impact on the temperature measurement accuracy of the temperature measuring resistor. Summary of the invention

[0005] The present application provides a brightness temperature calibration heat source for satellite-borne millimeter-wave and submillimeter-wave detectors, which is a high-temperature uniformity calibration heat source based on ultra-high emissivity and can adapt to complex orbital environments.

[0006] In order to achieve the above-mentioned purpose, the present application provides a brightness temperature calibration heat source for a satellite-borne millimeter-wave and submillimeter-wave detector, comprising a metal shell, a radiation substrate, a temperature measuring resistor, a heater, an insulation ring, a cover plate and an electrical connector, wherein: the radiation substrate is arranged above the inside of the metal shell; there are multiple temperature measuring resistors, and the multiple temperature measuring resistors are all arranged inside the radiation substrate; the heater is pasted on the back of the radiation substrate; the cover plate is fixed to the bottom of the metal shell; the insulation ring is arranged inside the metal shell, between the heater and the cover plate; the electrical connector is a low-frequency electrical connector, which is arranged on the outer wall of the metal shell and is electrically connected to the temperature measuring resistor and the heater respectively.

[0007] Furthermore, the metal shell includes a shell, a composite outer jacket, a thermal compensation heater and an electromagnetic shielding layer, wherein: the composite outer jacket is pasted on the inner wall of the shell; the thermal compensation heater is pasted on the inner wall of the composite outer jacket; and the electromagnetic shielding layer is pasted on the thermal compensation heater.

[0008] Furthermore, the composite material jacket is composed of carbon fiber; the thermal compensation heater is a polyimide film flexible heater; and the electromagnetic shielding layer is a double-sided aluminum-plated film.

[0009] Furthermore, the radiation substrate includes a metal structure and an absorbing coating, wherein: the absorbing coating is arranged above the front of the metal structure, and an anti-antigen oxygen protective film is sprayed on the surface; the back of the metal structure is provided with buried holes and serpentine wiring grooves; the buried holes are used to place temperature measuring resistors; and the serpentine wiring grooves are used for wiring multiple temperature measuring resistors.

[0010] Furthermore, the material of the metal structure is aluminum alloy; the wave-absorbing coating is a two-component curable epoxy resin-based ferrite coating; and the anti-proton oxygen protective film adopts SiC wave-transmitting material.

[0011] Furthermore, the heater adopts a double-layer redundant design, and a non-heating area is provided at a position corresponding to the buried hole.

[0012] Furthermore, an elastic thermal pad and a temperature equalizing plate are arranged between the heater and the insulation ring, wherein: the elastic thermal pad is a silicone rubber thermal pad, which is pasted on the heater; the temperature equalizing plate is made of copper, which is pasted on the elastic thermal pad and connected to the boss of the insulation ring.

[0013] Furthermore, the heat insulation ring is an epoxy glass cloth laminate 3240, which is a semi-open structure as a whole, and partition grooves are provided on the inside and outside.

[0014] Furthermore, a countersunk hole is provided at the bottom of the composite material jacket, and an insulating sleeve is provided inside the countersunk hole; connecting screws are sequentially passed through the insulating sleeve, the mounting holes on the insulating ring, the mounting holes on the temperature equalizing plate, the mounting holes on the elastic thermal pad, and the mounting holes on the heater, and then connected and fastened with the connecting threaded holes on the back of the metal structure.

[0015] Furthermore, thermal insulation cotton is arranged between the rear cover plate and the thermal insulation ring, and the material of the thermal insulation cotton is glass fiber.

[0016] The present application provides a heat source for calibrating brightness temperature of a satellite-borne millimeter-wave and submillimeter-wave detector, which has the following features:

[0017] Beneficial effects:

[0018] The present application adopts a combination of double-sided aluminum-plated film and a low thermal conductivity composite material shell. On the basis of meeting the requirements of electromagnetic interference protection, it effectively reduces the influence of "heat leakage" caused by heat transfer between the radiation substrate and the shell on the temperature uniformity of the radiation surface; at the same time, a compensating heater is designed on the shell, and the heat leakage is effectively compensated through the temperature control system, thereby greatly improving the uniformity of the radiation surface; and an anti-proton oxygen protective film with high wave-transmitting characteristics is sprayed on the surface of the absorbing coating to ensure the heat source emissivity and meet the application requirements of the low-orbit atomic oxygen environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings constituting a part of this application are used to provide a further understanding of this application, so that other features, purposes and advantages of this application become more obvious. The schematic embodiment drawings and their descriptions of this application are used to explain this application and do not constitute an improper limitation on this application. In the drawings:

[0020] Figure 1 It is a schematic diagram of a heat source for brightness temperature calibration of a satellite-borne millimeter-wave and submillimeter-wave detector according to an embodiment of the present application;

[0021] Figure 2 is a schematic diagram of the structure of a metal housing provided according to an embodiment of the present application;

[0022] Figure 3 is a schematic structural diagram of the back side of a radiation substrate provided according to an embodiment of the present application;

[0023] Figure 4 is a schematic diagram of the structure of a heater provided according to an embodiment of the present application;

[0024] Figure 5 is a schematic diagram of the structure of a heat insulation ring provided according to an embodiment of the present application;

[0025] Figure 6 is a schematic diagram of the structure of a temperature homogenizing plate provided according to an embodiment of the present application;

[0026] In the figure: 1-metal shell, 11-shell, 12-composite material jacket, 13-thermal compensation heater, 14-electromagnetic shielding layer, 15-insulation sleeve, 16-connecting screws, 2-radiation substrate, 21-metal structure, 22-wave absorbing coating, 23-buried hole, 24-snake-shaped wiring groove, 3-temperature measuring resistor, 4-heater, 41-non-heating area, 5-insulation ring, 51-boss, 52-partitioning groove, 6-cover plate, 7-electrical connector, 8-elastic thermal pad, 9-average temperature plate, 91-thermal resistance groove, 10-insulation cotton. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0028] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0029] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0030] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0031] In addition, the term "plurality" shall mean two or more.

[0032] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0033] like Figure 1 As shown, the present application provides a brightness temperature calibration heat source for a satellite-borne millimeter-wave and submillimeter-wave detector, comprising a metal shell 1, a radiation substrate 2, a temperature measuring resistor 3, a heater 4, an insulation ring 5, a cover plate 6 and an electric connector 7, wherein: the radiation substrate 2 is arranged above the inside of the metal shell 1; there are multiple temperature measuring resistors 3, and the multiple temperature measuring resistors 3 are all arranged inside the radiation substrate 2; the heater 4 is pasted on the back of the radiation substrate 2; the cover plate 6 is fixed to the bottom of the metal shell 1; the insulation ring 5 is arranged inside the metal shell 1, between the heater 4 and the cover plate 6; the electric connector 7 is a low-frequency electric connector 7, which is arranged on the outer wall of the metal shell 1 and is electrically connected to the temperature measuring resistor 3 and the heater 4 respectively.

[0034] Specifically, the satellite-borne millimeter-wave and submillimeter-wave detector brightness temperature calibration heat source provided in the embodiment of the present application is used as a key stand-alone device for calibration of satellite-borne microwave radiometers, providing accurate standard radiation brightness temperature for microwave radiometers, and having ultra-high emissivity and ultra-high temperature uniformity. Among them, the metal shell 1 is preferably in the shape of an open cylinder, and the radiation substrate 2 is mounted inside the metal shell 1 to shield external electromagnetic interference; the heater 4 is integrally attached to the back of the radiation substrate 2 to achieve heating of the radiation surface; the temperature measuring resistor 3 is buried inside the radiation substrate 2 to achieve monitoring of the radiation surface temperature; the thermal insulation ring 5 is arranged at the bottom of the metal shell 1 for overall thermal insulation; the cover plate 6 is fixed to the bottom of the metal shell 1, preferably using 2A12 aluminum alloy material, for sealing the entire metal shell 1; the electrical connector 7 is arranged at the connection port of the outer wall of the metal shell 1, preferably using a J36 series low-frequency electrical connector 7 for electrical connection with the outside world.

[0035] Further, such as Figure 2 As shown, the metal shell 1 includes a shell 11, a composite material jacket 12, a thermal compensation heater 13 and an electromagnetic shielding layer 14, wherein: the composite material jacket 12 is pasted on the inner wall of the shell 11; the thermal compensation heater 13 is pasted on the inner wall of the composite material jacket 12; and the electromagnetic shielding layer 14 is pasted on the thermal compensation heater 13.

[0036] Furthermore, the composite jacket 12 is made of carbon fiber; the thermal compensation heater 13 is a polyimide film flexible heater; and the electromagnetic shielding layer 14 is a double-sided aluminum-plated film with a thickness of preferably 0.2-0.5 mm.

[0037] Specifically, the embodiment of the present application adopts a combination of a double-sided aluminum-plated film and a low thermal conductivity composite material shell, which effectively reduces the influence of "heat leakage" caused by heat transfer between the radiation substrate 2 and the shell on the temperature uniformity of the radiation surface while meeting the requirements of electromagnetic interference protection; at the same time, a thermal compensation heater 13 is designed on the shell, and through the temperature control system, heat leakage is effectively compensated, thereby greatly improving the uniformity of the radiation surface.

[0038] Further, such as Figure 3 As shown, the radiation substrate 2 includes a metal structure 21 and an absorbing coating 22, wherein: the absorbing coating 22 is arranged above the front of the metal structure 21, and an anti-proton oxygen protective film is sprayed on the surface; the back of the metal structure 21 is provided with a buried hole 23 and a serpentine wiring groove 24; the buried hole 23 is used to place the temperature measuring resistor 3; the serpentine wiring groove 24 is used for wiring multiple temperature measuring resistors 3.

[0039] Furthermore, the material of the metal structure 21 is aluminum alloy; the wave-absorbing coating 22 is a two-component curable epoxy resin-based ferrite coating; and the anti-proton oxygen protective film is made of SiC wave-transmitting material.

[0040] Specifically, a plurality of temperature measuring resistors 3 are provided according to actual conditions, and all of them are buried in the embedding holes 23 corresponding to the metal structure 21, and their leads are buried in the serpentine wiring grooves 24; the temperature measuring resistors 3 are preferably four-wire temperature measuring PT100 platinum resistors, and the length of each serpentine wiring groove 24 is consistent, ensuring that the line resistance of each temperature measuring resistor 3 is completely equal after installation and does not affect each other, thereby eliminating the influence of the inconsistency of temperature measurement accuracy on temperature uniformity; and an anti-proton oxygen protective film with high wave-transmitting characteristics is sprayed on the surface of the absorbing coating 22 to ensure the heat source emissivity and meet the application requirements of the low-orbit atomic oxygen environment.

[0041] Furthermore, the heater 4 adopts a double-layer redundant design, and a non-heating area 41 is provided at a position corresponding to the buried hole 23. The heater 4 is provided with a non-heating area 41 having an area equal to that of the position corresponding to the buried hole 23, so as to reduce the temperature overshoot caused by direct thermal excitation of the temperature measuring resistor 3 and reduce the influence of the temperature measurement accuracy of the radiation surface on the temperature uniformity.

[0042] Furthermore, an elastic thermal pad 8 and a temperature averaging plate 9 are provided between the heater 4 and the thermal insulation ring 5, wherein: the elastic thermal pad 8 is a silicone rubber thermal pad, which is pasted on the heater 4; the temperature averaging plate 9 is made of red copper, which is pasted on the elastic thermal pad 8 and connected to the boss 51 of the thermal insulation ring 5. The elastic thermal pad 8 can reduce the tensile deformation of the heater 4 caused by the expansion of the pasted surface, thereby avoiding damage to the heater 4; the temperature averaging plate 9 is made of a metal material with high thermal conductivity, preferably red copper, and the mounting surface with the radiation substrate 2 is designed to be a plane, and a thermal resistance groove 91 is designed in the contact area with the thermal insulation ring 5 to ensure temperature uniformity.

[0043] Furthermore, the heat insulating ring 5 is an epoxy glass cloth laminate 3240, which is a semi-open structure as a whole, and partition grooves 52 are arranged on both the inside and outside. The heat insulating ring 5 is a semi-open design, and partition grooves 52 are designed on the inside and outside. The contact area with the temperature balancing plate 9 is designed in the shape of a boss 51 for heat insulation.

[0044] Furthermore, a countersunk hole is provided at the bottom of the composite jacket 12, and a heat insulating sleeve 15 is provided inside the countersunk hole; the connecting screw 16 is passed through the heat insulating sleeve 15, the mounting hole on the heat insulating ring 5, the mounting hole on the temperature averaging plate 9, the mounting hole on the elastic heat conductive pad 8, and the mounting hole on the heater 4 in sequence, and then connected and fastened with the connecting threaded hole on the back of the metal structure 21. A countersunk hole is provided at the bottom of the composite jacket 12, and a heat insulating sleeve 15 is provided inside the countersunk hole, and mounting holes are provided at corresponding positions of the heat insulating ring 5, the temperature averaging plate 9, the elastic heat conductive pad 8 and the heater 4; the material of the connecting screw 16 is preferably TC4 titanium alloy. During assembly, the connecting screw 16 is passed through the countersunk heat insulating sleeve 15 and each mounting hole in sequence from bottom to top, and the overall structure is fixedly installed on the back of the metal structure 21 to ensure the stability of the overall structure.

[0045] Furthermore, a heat-insulating cotton 10 is provided between the rear cover plate 6 and the heat-insulating ring 5, and the material of the heat-insulating cotton 10 is glass fiber. The rear cover plate 6 serves as the bottom surface of the metal shell 1 and plays a role of packaging and fixing. The heat-insulating cotton 10 made of glass fiber is provided between the rear cover plate 6 and the heat-insulating ring 5 for heat preservation of the whole heat source.

[0046] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A heat source for brightness temperature calibration of satellite-borne millimeter-wave and submillimeter-wave detectors, characterized in that: It includes a metal shell, a radiation substrate, a temperature measuring resistor, a heater, a heat insulation ring, a cover plate and an electrical connector, wherein: The radiation substrate is arranged above the interior of the metal shell; There are multiple temperature measuring resistors, and the multiple temperature measuring resistors are all arranged inside the radiation substrate; The heater is attached to the back of the radiation substrate; The cover plate is fixed to the bottom of the metal shell; The heat insulation ring is arranged inside the metal shell and between the heater and the cover plate; The electric connector is a low-frequency electric connector, which is arranged on the outer wall of the metal shell and is electrically connected to the temperature measuring resistor and the heater respectively.

2. The brightness temperature calibration heat source for satellite-borne millimeter-wave and submillimeter-wave detectors according to claim 1, characterized in that: The metal shell includes a shell, a composite material outer shell, a thermal compensation heater and an electromagnetic shielding layer, wherein: The composite material jacket is adhered to the inner wall of the shell; The thermal compensation heater is adhered to the inner wall of the composite material jacket; The electromagnetic shielding layer is adhered to the thermal compensation heater.

3. The brightness temperature calibration heat source for satellite-borne millimeter-wave and submillimeter-wave detectors according to claim 2, characterized in that: The composite material jacket is composed of carbon fiber; the thermal compensation heater is a polyimide film flexible heater; and the electromagnetic shielding layer is a double-sided aluminum-plated film.

4. The brightness temperature calibration heat source for satellite-borne millimeter-wave and submillimeter-wave detectors according to claim 3, characterized in that: The radiation substrate comprises a metal structure and a radar absorbing coating, wherein: The wave-absorbing coating is arranged above the front surface of the metal structure, and an anti-proton oxygen protective film is sprayed on the surface; The back of the metal structure is provided with embedded holes and serpentine wiring grooves; The buried hole is used to place the temperature measuring resistor; The serpentine wiring trough is used for wiring of a plurality of the temperature measuring resistors.

5. The brightness temperature calibration heat source for satellite-borne millimeter-wave and submillimeter-wave detectors according to claim 4, characterized in that: The material of the metal structure is aluminum alloy; the wave-absorbing coating is a two-component curable epoxy resin-based ferrite coating; and the anti-proton oxygen protective film is made of SiC wave-transmitting material.

6. The brightness temperature calibration heat source for satellite-borne millimeter-wave and submillimeter-wave detectors according to claim 5, characterized in that: The heater adopts a double-layer redundant design, and a non-heating area is arranged at a position corresponding to the buried hole.

7. The brightness temperature calibration heat source for satellite-borne millimeter-wave and submillimeter-wave detectors according to claim 6, characterized in that: An elastic thermal pad and a temperature averaging plate are provided between the heater and the thermal insulation ring, wherein: The elastic thermal pad is a silicone rubber thermal pad, which is pasted on the heater; The temperature homogenizing plate is made of red copper, is adhered to the elastic thermal pad, and is connected to the boss of the thermal insulation ring.

8. The brightness temperature calibration heat source for satellite-borne millimeter-wave and submillimeter-wave detectors according to claim 7, characterized in that: The heat insulation ring is an epoxy glass cloth laminate 3240, which is a semi-open structure as a whole, and is provided with partition grooves on the inside and outside.

9. The brightness temperature calibration heat source for satellite-borne millimeter-wave and submillimeter-wave detectors according to claim 8, characterized in that: A countersunk hole is provided at the bottom of the composite material jacket, and a heat insulating sleeve is provided inside the countersunk hole; connecting screws are sequentially passed through the heat insulating sleeve, the mounting hole on the heat insulating ring, the mounting hole on the temperature equalizing plate, the mounting hole on the elastic thermal pad, and the mounting hole on the heater, and then connected and fastened with the connecting threaded holes on the back side of the metal structure.

10. The brightness temperature calibration heat source for satellite-borne millimeter-wave and submillimeter-wave detectors according to claim 9, characterized in that: Insulation cotton is also arranged between the rear cover plate and the insulation ring, and the material of the insulation cotton is glass fiber.

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