Broadband superstructure on-satellite calibration black body device

Abstract

The device comprises a light shield, a calibration shutter, a metamaterial gallium fixed point black body, a support frame, a double-layer optical filter, a multi-stage temperature control cavity, a detector, a first aperture diaphragm, a second aperture diaphragm, a field diaphragm, an isotope heat source and a control circuit. Wherein the light shield is arranged at the upper part of the supporting frame; the calibration shutter is arranged in the middle of the supporting frame; the super-structure gallium fixed point black body is installed on the calibration shutter. The multi-stage temperature control cavity is arranged at the lower part of the supporting frame; the double-layer optical filter and the detector are arranged in the multi-stage temperature control cavity; the field diaphragm is arranged on the inner wall of the multi-stage temperature control cavity and is positioned at the lower part of the calibration shutter; the first aperture diaphragm and the second aperture diaphragm are arranged on the inner wall of the multi-stage temperature control cavity; the isotope heat source is connected with the multi-stage temperature control cavity; and the control circuit is connected with the calibration shutter and is used for controlling the calibration shutter. The device has the excellent performance of being accurate in measurement, stable in control and accurate in positioning.

Description

Technical Field

[0001] The invention belongs to the technical field of aerospace remote sensing, and in particular relates to a wide-band super-satellite on-board calibration blackbody device. Background Art

[0002] Highly stable on-orbit radiation benchmarks are the premise and guarantee for the availability of deep space exploration payloads on-orbit. The study of global climate change by detecting the Earth's radiation budget places extremely high demands on the detection accuracy and on-orbit stability of radiometers. The changes in radiation budget caused by changes in the Earth's climate environment are extremely small. If the on-orbit performance of radiation detection equipment drifts, the data accuracy will deteriorate and it will be impossible to accurately predict long-term climate change trends. Summary of the invention

[0003] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art and provide a wide-band super-structure on-board calibration blackbody device, which has the excellent performance of precise measurement, stable control and accurate determination, and can realize the on-orbit calibration requirements of deep space detection radiometers with ultra-wide band, ultra-high emissivity, high-precision temperature measurement and control accuracy, and traceable temperature benchmark.

[0004] The object of the present invention is achieved through the following technical solutions: A wide-band super-satellite on-board calibration blackbody device, comprising: a light shield, a calibration shutter, a super-gallium fixed-point blackbody, a support frame, a double-layer filter, a multi-stage temperature control cavity, a detector, a first aperture diaphragm, a second aperture diaphragm, a field diaphragm, an isotope heat source and a control circuit; wherein the light shield is arranged at the upper part of the support frame; the calibration shutter is arranged at the middle part of the support frame; the super-gallium fixed-point blackbody is installed on the calibration shutter; the multi-stage temperature control cavity is arranged at the lower part of the support frame, the double-layer filter and the detector are both arranged in the multi-stage temperature control cavity, and the The double-layer filter is located at the bottom of the metagallium fixed-point black body, and the detector is located at the bottom of the double-layer filter; the field diaphragm is arranged on the inner wall of the multi-stage temperature control cavity, and the field diaphragm is located at the bottom of the calibration shutter; the first aperture diaphragm and the second aperture diaphragm are both arranged on the inner wall of the multi-stage temperature control cavity, the position of the first aperture diaphragm corresponds to the position of the double-layer filter, and the position of the second aperture diaphragm corresponds to the position of the detector; the isotope heat source is connected to the multi-stage temperature control cavity; the control circuit is connected to the calibration shutter, and the control circuit is used to control the calibration shutter.

[0005] In the above-mentioned wide-band superstructure on-board calibration blackbody device, the light shield is used to suppress background stray light; the calibration shutter is used to realize the on-orbit observation and on-orbit calibration of the deep space exploration radiometer on the earth; the superstructure gallium fixed-point blackbody is used to provide calibration reference temperature point radiation information during the on-orbit radiation calibration of the deep space exploration payload; the detector is used to extract the radiation information of the observed earth target, the cold sky background and the superstructure gallium fixed-point blackbody.

[0006] In the above-mentioned wide-band superstructure satellite on-board calibration blackbody device, the superstructure gallium fixed-point blackbody includes a carbon nanotube array coating, a superstructure graphite top cover, a graphite crucible, metal gallium, a heating plate, a temperature sensor and an rubber ring plug; wherein, the carbon nanotube array coating is deposited on the upper surface of the superstructure graphite top cover; the lower surface of the superstructure graphite top cover is glued to the graphite crucible to form a hollow cylindrical shape; a filling port is reserved at the bottom of the graphite crucible, and the metal gallium is injected into the graphite crucible through the filling port, and the filling port of the graphite crucible is glued and sealed with the rubber ring plug; the temperature sensor is glued in the bottom groove of the graphite crucible; the heating plate is connected to the bottom of the graphite crucible.

[0007] In the above-mentioned wide-band superstructure on-satellite calibration blackbody device, the superstructure gallium fixed-point blackbody also includes a polytetrafluoroethylene protective layer; wherein the lower surface of the graphite top cover and the inner wall of the graphite crucible are both sprayed with the polytetrafluoroethylene protective layer.

[0008] In the above-mentioned wide-band superstructure on-board calibration blackbody device, the superstructure gallium fixed-point blackbody is installed on the calibration shutter through a connecting device.

[0009] In the above-mentioned wide-band superstructure on-satellite calibration blackbody device, the connecting device includes screws, a pressing plate, a rubber ring and a metal shell; wherein the superstructure gallium fixed-point blackbody is arranged in the metal shell; the pressing plate and the rubber ring are both connected to the top of the metal shell through the screws, and the rubber ring is located between the pressing plate and the metal shell; the metal shell is connected to the calibration shutter.

[0010] In the above-mentioned wide-band supersatellite on-board calibration blackbody device, the multi-stage temperature-controlled cavity includes a primary temperature-controlled cavity, a secondary temperature-controlled cavity and a tertiary temperature-controlled cavity; wherein the primary temperature-controlled cavity is connected to the lower part of the support frame; the primary temperature-controlled cavity and the secondary temperature-controlled cavity are both connected to the tertiary temperature-controlled cavity; the secondary temperature-controlled cavity is located inside the primary temperature-controlled cavity, and part of the primary temperature-controlled cavity is located inside the secondary temperature-controlled cavity; the double-layer filter and the detector are both arranged in the tertiary temperature-controlled cavity; the field diaphragm, the first aperture diaphragm and the second aperture diaphragm are all arranged on the inner wall of the multi-stage temperature-controlled cavity.

[0011] In the above-mentioned wide-band superstructure on-board calibration blackbody device, in standby mode, the temperature of the superstructure gallium fixed-point blackbody is maintained at 29.76°C; after entering the measurement mode or the on-orbit calibration mode, the calibration shutter is first opened to observe the earth or deep space. While the calibration shutter is open, the superstructure gallium fixed-point blackbody is heated, and the heating is stopped after reaching the melting temperature of metal gallium, and then the metal gallium is cooled to enter the plateau period, ensuring that the plateau preparation period time Tp is within the shutter opening time period; then the calibration shutter is closed, and the detector measures the radiation of the superstructure gallium fixed-point blackbody. At this time, the metal gallium of the superstructure gallium fixed-point blackbody remains in the plateau period, and the platform holding period time Tu+plateau preparation time Tp is required to be ≥10min, so that the metal gallium is always in the plateau period during the closing of the calibration shutter.

[0012] In the above-mentioned wide-band superconstructor on-board calibration blackbody device, the filling amount of metal gallium accounts for 80% to 90% of the volume of the graphite crucible.

[0013] In the above-mentioned wide-band superconstructor on-board calibration blackbody device, the double-layer filter has high transmittance in the spectral ranges of 0.2μm to 4.3μm, 0.7μm to 4.3μm, and 4.3μm to 100μm respectively.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The present invention proposes to use a fixed-point black body as a radiometer shutter and proposes an optimized on-orbit working mode for the radiometer. The on-orbit radiation calibration is organically integrated with earth observation, so that each shutter-closed measurement state becomes a part of the on-orbit radiation calibration, ensuring that each measurement result of earth radiation can correct the influence of the radiometer's own instability, ensuring high-precision measurement throughout the life cycle of the radiometer. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0017] Figure 1 is a schematic diagram of a blackbody calibration device on a wide-band supersatellite provided by an embodiment of the present invention;

[0018] Figure 2 It is a calibration strategy diagram of a blackbody device for calibration on a satellite provided by an embodiment of the present invention;

[0019] Figure 3 is a design diagram of a gallium fixed-point blackbody structure provided by an embodiment of the present invention;

[0020] Figure 4is a schematic structural diagram of a connecting device provided by an embodiment of the present invention;

[0021] Figure 5 This is a working timing diagram of the on-board blackbody calibration device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0022] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to be able to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features described in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0023] Studying global climate change by detecting the Earth's radiation budget has extremely high requirements for the detection accuracy and on-orbit stability of the radiometer. Although the absolute radiometer has the characteristics of high precision, its on-orbit performance will be affected by the performance degradation of the filter and ultra-black coating, as well as the ambient temperature drift. The radiation detection equipment has an on-orbit calibration function. By tracing back to the standard temperature point of the international temperature scale, it can monitor and correct the decline of instrument performance, establish a relationship with the high-precision radiation calibration value on the ground, and maintain the accuracy of the on-orbit data. Therefore, on-orbit radiation calibration is of great significance for obtaining accurate and reliable scientific data.

[0024] The main scientific task of the lunar-based earth observation radiometer is to obtain the radiation expenditure at the top of the earth's atmosphere on the lunar surface. The lunar-based earth radiation detection has the characteristics of weak target energy, wide detection spectrum, high sensitivity, large ambient temperature difference, and strong stray light interference. The lunar-based radiometer on-orbit calibration calibrates the instrument's own changes by observing the stable deep space equivalent to 4K temperature, and realizes the two-point calibration of the instrument by adding the observation of a fixed-point black body that is stable during the phase change material platform period, thereby improving the calibration accuracy.

[0025] The energy radiated outward from the top of the Earth's atmosphere includes reflected solar energy and the infrared radiation energy of the atmosphere itself, and its energy is mainly distributed in the range of 0.2μm to 100μm. Among them, 0.2μm to 4.3μm is the solar reflection spectrum; 0.7μm to 4.3μm is the solar near-infrared spectrum; 4.3μm to 100μm is the earth's infrared radiation spectrum. Therefore, the radiometer needs to have the function of full-spectrum energy detection. Considering the measurement of the total outgoing radiation of the earth in the design, the radiometer needs to have a wide-spectrum response capability. Different spectral screening filters need to be designed to accurately screen the radiation information of the solar reflection spectrum, the solar near-infrared spectrum and the earth's infrared radiation spectrum, and then measure and extract the radiation target information after accurate screening through the detector.

[0026] At the top of the Earth's atmosphere, radiation is the only way to exchange energy. The radiation difference at the top of the Earth's atmosphere reflects how much energy the Earth system accumulates or releases, and is one of the most important overall indicators of global climate change. The Moon is a permanent Earth observation platform that can provide long-term, accurately calibrated time series data, which will greatly facilitate the study of changes in the Earth's climate system; secondly, the Moon always faces the Earth with its front side, and an observation station on the front side of the Moon only needs a very small field of view (about <5°) to observe the full disk image of the Earth and continuously obtain the overall radiation data of the Earth's hemisphere.

[0027] After the radiometer enters the measurement mode and the on-orbit calibration mode, the radiometer opens the shutter for 5 minutes and then closes the shutter for 5 minutes as a cycle (a total of 10 minutes) to perform periodic radiation measurement. The gallium fixed-point blackbody works in the same cycle by preparing to work during the shutter opening period and maintaining the plateau period during the shutter closing period.

[0028] The wide-band super-construction on-board calibration blackbody device of this embodiment can realize the use of the gallium fixed-point blackbody on the shutter and the deep space background as the value traceability standard under on-orbit conditions. The deep space background, that is, the background radiation of the deep space of the universe, is a radiation from the early universe, which provides important information about the origin and evolution of the universe. As a traceability standard, the deep space background has the following characteristics: Universality: The deep space background radiation exists throughout the universe and provides a common background reference for all celestial bodies. Stability: The deep space background radiation has remained stable over the past few decades, making it a reliable traceability standard. When designing the on-board gallium fixed-point blackbody radiation source, on the one hand, it is necessary to maintain the excellent thermal conductivity between gallium and the blackbody cavity, so as to minimize the temperature gradient between gallium and the radiation surface of the blackbody cavity; on the other hand, it is necessary to provide a stable heat source for gallium melting to obtain an ideal phase change plateau; at the same time, in order to reduce the influence of environmental radiation on the radiation value of the blackbody cavity, it is necessary to maximize the emissivity of the blackbody radiation surface.

[0029] Figure 1Schematic diagram of a calibration blackbody device on a wide-band supersatellite provided by an embodiment of the present invention. Figure 1 As shown, the wide-band super-satellite on-board calibration blackbody device comprises: a light shield 1, a calibration shutter 2, a super-gallium fixed-point blackbody 3, a support frame 4, a double-layer filter 5, a multi-stage temperature control cavity 6, a detector 7, a first aperture diaphragm 81, a second aperture diaphragm 82, a field diaphragm 9, an isotope heat source 10 and a control circuit 11; wherein, the light shield 1 is arranged at the upper part of the support frame 4; the calibration shutter 2 is arranged at the middle part of the support frame 4; the super-gallium fixed-point blackbody 3 is installed on the calibration shutter 2; the multi-stage temperature control cavity 6 is arranged at the lower part of the support frame 4, the double-layer filter 5 and the detector 7 are both arranged in the multi-stage temperature control cavity 6, and the double-layer filter 5 and the detector 7 are arranged in the multi-stage temperature control cavity 6. The double-layer filter 5 is located at the lower part of the metagallium fixed-point blackbody 3, and the detector 7 is located at the lower part of the double-layer filter 5; the field diaphragm 9 is arranged on the inner wall of the multi-stage temperature control cavity 6, and the field diaphragm 9 is located at the lower part of the calibration shutter 2; the first aperture diaphragm 81 and the second aperture diaphragm 82 are both arranged on the inner wall of the multi-stage temperature control cavity 6, the position of the first aperture diaphragm 81 corresponds to the position of the double-layer filter 5, and the position of the second aperture diaphragm 82 corresponds to the position of the detector 7; the isotope heat source 10 is connected to the multi-stage temperature control cavity 6; the control circuit 11 is connected to the calibration shutter 2, and the control circuit 11 is used to control the calibration shutter 2.

[0030] Light shield 1, used to suppress background stray light.

[0031] The calibration shutter 2 is used to realize the observation and calibration of the deep space detection radiometer on the earth on orbit. It is driven by the adjustment mechanism to realize the switching between the observation and calibration modes.

[0032] The hypergallium fixed-point blackbody 3 is used to provide the radiation information of the calibration reference temperature point during the on-orbit radiation calibration of deep space exploration payloads.

[0033] The support frame 4 is used to support and connect various functional components, and is designed with an installation interface for installation with the satellite platform. The support frame 4 is made of titanium alloy and needs to be lightweight in accordance with the on-orbit mechanical conditions and mass reduction requirements.

[0034] The double-layer filter 5 can improve the stability of the filter and realize accurate screening of the observed spectrum. The double-layer filter 5 is installed on the filter wheel support plate, and the filter wheel support plate is driven by the filter wheel mechanism to realize the switching of the required filter spectrum bands.

[0035] The multi-stage temperature control chamber 6 realizes precise temperature control of the radiometer working temperature.

[0036] The detector 7 is used to measure, extract and transmit the radiation information of the observed earth target, cold sky background and gallium fixed point black body 3.

[0037] The aperture stop 8 and the field stop 9 are used to suppress background stray light.

[0038] The isotope heat source 10 is used to provide thermal insulation protection for the radiometer payload during non-working hours at night.

[0039] The control circuit 11 controls and supplies power to the radiometer during observation and calibration.

[0040] The main function of the graphite crucible 33 is to hold high-purity gallium, and its structural design should be convenient for metal infusion; the cavity wall should be as thin as possible to reduce the temperature difference between the inner and outer walls after ensuring machinability and sealing, so as to obtain the largest possible isothermal zone.

[0041] The GaS fixed point blackbody 3 is installed on the radiometer calibration shutter 2 and used as the on-orbit radiation calibration reference. During the closing of the calibration shutter 2, the surface of the GaS fixed point blackbody 3 is aligned with the radiation detection assembly, and the radiometer observes the blackbody radiation. The GaS fixed point blackbody 3 can not only provide a long-term stable shutter radiation power reference, but also monitor and correct the long-term performance degradation of the system on-orbit, realizing the on-orbit radiation calibration function.

[0042] like Figure 3 As shown, the super-structured gallium fixed-point blackbody 3 includes a carbon nanotube array coating 31, a super-structured graphite top cover 32, a graphite crucible 33, a metal gallium 35, a heating plate 36, a temperature sensor 37 and a rubber ring plug 38; wherein, the carbon nanotube array coating 31 is deposited on the upper surface of the super-structured graphite top cover 32; the lower surface of the super-structured graphite top cover 32 is glued to the graphite crucible 33 to form a hollow cylindrical shape; a pouring port is reserved at the bottom of the graphite crucible 33, and the metal gallium 35 is injected into the graphite crucible 33 through the pouring port, and the pouring port of the graphite crucible 33 is glued and sealed with the rubber ring plug 38; the temperature sensor 37 is glued in the bottom groove of the graphite crucible 33; the heating plate 36 is connected to the bottom of the graphite crucible 33.

[0043] like Figure 3 As shown, the metagallium fixed-point blackbody 3 further includes a polytetrafluoroethylene protective layer 34 ; wherein the lower surface of the graphite top cover 32 and the inner wall of the graphite crucible 33 are both sprayed with the polytetrafluoroethylene protective layer 34 .

[0044] The carbon nanotube array coating 31 is deposited on the upper surface of the super-graphite top cover 32. The lower surface of the super-graphite top cover 32 is glued to the graphite crucible 33 to form a hollow cylindrical shape. A pouring port is left at the bottom of the graphite crucible 33. After the metal gallium 35 is poured into the inside of the hollow cylindrical cavity through the pouring port, the pouring port of the graphite crucible 33 is glued and sealed with a rubber ring plug 38. The carbon nanotube ultra-black radiation surface 31 is grown on the surface of the super-graphite top cover 32 and faces the radiation detector 7, serving as the calibration blackbody radiation surface on the star. The temperature sensor 37 is glued in the sink groove on the bottom surface of the graphite crucible 33. A layer of polytetrafluoroethylene protective layer 34 is sprayed on the lower surface of the graphite top cover 32 and the inner wall of the graphite crucible 33 to isolate the contact reaction between the metal gallium 35 and the graphite crucible 33 and the super-graphite top cover 32. The high-precision temperature sensor 37 is used to accurately measure the temperature of the super-gallium fixed point blackbody 3.

[0045] like Figure 4 As shown, the connecting device includes a screw 41, a pressing plate 42, a rubber ring 43 and a metal shell 44; wherein the metagallium fixed point blackbody 3 is arranged in the metal shell 44; the pressing plate 42 and the rubber ring 43 are connected to the top of the metal shell 44 through the screw 41, and the rubber ring 43 is located between the pressing plate 42 and the metal shell 44; the metal shell 44 is connected to the calibration shutter 2.

[0046] The entirety of the GaS fixed point black body 3 is connected by screws 41 and fixed to a metal housing 44 by a pressing sheet 42 and a rubber ring 43. The metal housing is designed with an external mounting hole 45 to achieve the connection between the GaS fixed point black body 3 and the calibration shutter.

[0047] The multi-stage temperature control chamber 6 includes: the outermost primary temperature control, the middle secondary temperature control, and the innermost tertiary temperature control. The multi-stage temperature control chamber 6 includes at least three layers but is not limited to three layers, and the number of layers can be increased or decreased according to the temperature control needs.

[0048] like Figure 1 As shown, the multi-stage temperature control chamber 6 includes a primary temperature control chamber, a secondary temperature control chamber and a tertiary temperature control chamber; wherein, the primary temperature control chamber is connected to the lower part of the support frame 4; the primary temperature control chamber and the secondary temperature control chamber are both connected to the tertiary temperature control chamber; the secondary temperature control chamber is located inside the primary temperature control chamber, and part of the primary temperature control chamber is located inside the secondary temperature control chamber; the double-layer filter 5 and the detector 7 are both arranged in the tertiary temperature control chamber; the field diaphragm 9, the first aperture diaphragm 81 and the second aperture diaphragm 82 are all arranged on the inner wall of the multi-stage temperature control chamber 6.

[0049] like Figure 2 and Figure 5As shown, in the standby mode, the temperature of the supergallium fixed-point blackbody 3 is controlled to be maintained at 29.76°C; after entering the measurement mode or the on-orbit calibration mode, the calibration shutter 2 is first opened to observe the earth or deep space. While the calibration shutter 2 is opened, the supergallium fixed-point blackbody 3 is heated, and the heating is stopped after the melting temperature of the metal gallium is reached, and then the metal gallium is cooled to enter the plateau period, ensuring that the plateau preparation period time Tp is within the shutter opening time period; then the calibration shutter 2 is closed, and the detector 7 measures the radiation of the supergallium fixed-point blackbody 3. At this time, the metal gallium of the supergallium fixed-point blackbody 3 is maintained in the plateau period, and the platform holding period time Tu+plateau preparation time Tp is required to be ≥10min, so that the metal gallium is always in the plateau period during the closing of the calibration shutter 2.

[0050] The on-orbit radiation calibration is organically integrated with the earth observation, so that each closed measurement state of the calibration shutter 2 becomes a part of the on-orbit radiation calibration, ensuring that each measurement result of the earth radiation can correct the instability of the radiometer itself, ensuring high-precision measurement throughout the life cycle of the radiometer. The black body is on the shutter, and the shutter is driven by the adjustment mechanism and can be rotated. When the calibration black body is aligned with the radiation detection component, the on-orbit calibration work can be carried out.

[0051] like Figure 2 As shown in the calibration strategy diagram of the wide-band superconstructor on-board calibration blackbody device of the present invention, in standby mode, the temperature of the gallium fixed-point blackbody is maintained at 29.76°C. After entering the measurement mode or the on-orbit calibration mode, the shutter is first opened to observe the earth or deep space. While the shutter is open, the gallium fixed-point blackbody 3 is heated, and the heating is stopped after reaching the designed gallium melting temperature point, and then the gallium is cooled to enter the plateau period, ensuring that the plateau preparation period Tp (the time from the start of heating to the entry into the plateau period) is within the shutter opening time period, that is, Tp < 5min. Then the shutter is closed, and the radiation of the gallium fixed-point black body is measured. At this time, the gallium of the gallium fixed-point black body remains in the plateau period. The plateau holding period time (Tu) + plateau preparation time (Tp) is required to be ≥ 10min, so that the gallium is always in the plateau period during the shutter closing period. After one cycle of measurement is completed, the program determines whether to exit the measurement / calibration mode. If not, it enters the next shutter opening and shutter closing measurement cycle. If exited, the program further determines whether to enter the standby mode. If it enters the standby mode, the calibration black body temperature control is maintained at 29.76℃ (tentative). If the standby mode is exited, the calibration black body exits the temperature control and the radiometer enters the shutdown mode.

[0052] like Figure 3As shown, the structural layout diagram of the wide-band super-satellite calibration blackbody device of the present invention, the core components of the wide-band super-satellite calibration blackbody device include: a super-gallium fixed-point blackbody 3, which needs to be clamped by a super-surface microstructure in the range of 0.2μm to 100μm for high emissivity performance. A double-layer filter has high transmittance in the spectral ranges of 0.2μm to 4.3μm (quartz substrate), 0.7μm to 4.3μm (quartz substrate), and 4.3μm to 100μm (diamond substrate). For filters in the 4.3μm to 100μm spectral range, a diamond substrate material needs to be used to increase the response, and a super-surface microstructure needs to be processed on the surface of the diamond substrate to increase its transmittance. A filter wheel is used to fix and switch the filter. A rotating filter wheel is used to select the corresponding filter according to the band. The filter is fixed on the filter plate by a pressure ring. The filter wheel adopts a heat-insulating design, and a heat-insulating gasket is added in the middle to ensure the heat-insulating connection between the filter wheels and effectively shield the stray radiation caused by thermal radiation.

[0053] In order to obtain high-precision radiation measurement, a stable thermal environment with a temperature of 0.01mK~0.08mK@10min will be provided for the detector, and a three-level temperature control cavity 6 will be designed. The first level is the main shell, the second level is the temperature control cavity, and the third level is the environmental cavity of the detector. The first-level main shell material is selected from high thermal conductivity asphalt-based carbon fiber, the outer surface is covered with 18 units of multi-layer thermal insulation components, and the inner surface is covered with 8 units of multi-layer. Three-way active temperature control is designed, each with 1W~5W, and the temperature control point is 3℃~10℃. Isotope heat sources, motors and other internal heat sources are installed on the main shell to reduce the impact of internal heat source disturbances on the internal detector environment cavity; the main shell and the turntable are thermally insulated. The secondary temperature control cavity is made of 2A12O aluminum alloy, with polished inner and outer surfaces, and the thermal insulation support is on the primary main shell; 3-way active temperature control is designed, each with a power of 0.1~3W, and the temperature control point is 20℃±1℃. Thermal insulation support is provided between the secondary temperature control cavity and the primary shell. The third-level temperature control cavity is the detector environment cavity, which is the detector heat sink. The material is oxygen-free copper and designed with a certain thickness of 3mm to 8mm to improve its own temperature uniformity and total heat capacity. The inner and outer surfaces of the environmental cavity are gold-plated to reduce the infrared emissivity. The third-level cavity is thermally insulated and supported on the second-level cavity. Each channel's environmental cavity is designed with a high-frequency temperature control circuit, with a temperature control point of 29.76℃ and a control frequency of about 80Hz to 120Hz. The temperature control element uses a barium strontium titanate sensor.

[0054] The carbon nanotube array coating 31 is deposited on the upper surface of the super-graphite top cover 32. The lower surface of the super-graphite top cover 32 is glued to the graphite crucible 33 to form a hollow cylindrical shape. A pouring port is left at the bottom of the graphite crucible 33. After the metal gallium 35 is poured into the inside of the hollow cylindrical cavity through the pouring port, the pouring port of the graphite crucible 33 is glued and sealed with a rubber ring plug 38. The carbon nanotube ultra-black radiation surface 31 is grown on the surface of the super-graphite top cover 32 and faces the radiation detector 7, serving as the calibration blackbody radiation surface on the satellite. The barium strontium titanate temperature sensor 37 is glued in the sink groove on the bottom surface of the graphite crucible 33 to accurately measure the temperature of the super-graphite fixed point blackbody 3. A layer of polytetrafluoroethylene protective layer 34 is sprayed on the lower surface of the graphite top cover 32 and the inner wall of the graphite crucible 33 to isolate the contact reaction between the metal gallium 35 and the graphite crucible 33 and the super-graphite top cover 32. The barium strontium titanate high-precision temperature sensor 37 is used to accurately measure the temperature of the super-structure gallium fixed-point black body 3.

[0055] The carbon nanotube ultra-black radiation surface 31 and the super-structured graphite top cover 32 need to deposit a carbon nanotube ultra-black coating 31 on the sealed bottom cover before the metal gallium is infused as the high-emissivity radiation surface of the calibration black body. First, an adhesion layer is deposited on the outside of the graphite top cover 32 to improve the adhesion of the ultra-black coating to the substrate, and then the carbon nanotube ultra-black coating is deposited. The emissivity of the carbon nanotube ultra-black coating should be greater than 0.995 to ensure the accuracy and stability of the value transfer. The preferred carbon nanotube array (height of 80μm to 150μm) is processed by plasma chemical vapor deposition. After the ultra-black material is deposited on the sealing cover, the graphite top cover 32 is bonded to the graphite crucible 33, and its overall mechanical strength and sealing performance are improved by encapsulating the outer shell 44.

[0056] The super-structured graphite top cover 32 needs to be provided with a super-surface structure to enhance the light trapping performance of the radiation surface and improve the emissivity, and can also improve the adhesion of the super-black coating to the substrate.

[0057] The main function of the graphite crucible 33 is to hold high-purity gallium 35. Its design needs to ensure that: the structural design should be convenient for metal infusion; the cavity wall should be as thin as possible to reduce the temperature difference between the inner and outer walls after ensuring machinability and sealing; and the isothermal area should be as large as possible. The side of the graphite crucible 33 is opened with an infusion hole for infusing high-purity gallium 35. The main body of the graphite crucible 33 can be made of high thermal conductivity PA6 nylon / graphite composite material.

[0058] A special slot is provided at the bottom of the graphite crucible 33 for fixing the barium strontium titanate temperature sensor 37. This design ensures that the temperature sensor can continuously and stably contact the side of the crucible containing the gallium metal no matter how the instrument rotates, thereby ensuring the accuracy and real-time performance of temperature monitoring. The diameter of the temperature sensor is 6 mm and the thickness is 3 mm.

[0059] Filling of metal gallium 34: The manufactured graphite crucible 33 needs to be filled with high-purity metal gallium, whose purity reaches 7N level (7N purity gallium: 99.99999%), and the filling amount accounts for 80% to 90% of the crucible volume to prevent the volume change of about 2% to 5% during the phase change of metal gallium, ensuring sufficient heat conduction efficiency and performance requirements.

[0060] Polytetrafluoroethylene protective layer 34, polytetrafluoroethylene (PTFE) is selected as the heat insulation material of the graphite crucible due to its excellent heat resistance, corrosion resistance and non-stickiness. The main functions of the polytetrafluoroethylene protective layer 34 include two aspects. First, as a heat insulation layer, it effectively reduces the heat exchange between the graphite crucible and the external environment, making the temperature inside the crucible more stable. Secondly, due to the corrosion resistance of polytetrafluoroethylene, it can also effectively prevent the leakage of metal gallium, ensuring the safety of the experiment or production process.

[0061] The temperature sensor can monitor temperature changes through its own resistance temperature effect, and convert the temperature changes into electrical signal output through the measurement circuit. In the lunar-based earth observation radiometer, the temperature change of the radiation detection component is monitored with high precision through the temperature sensor, and the electrical substitution compensation power is adjusted through feedback control so that it produces the same heating effect as the optical power, thereby achieving high-precision measurement of the incident radiation. Therefore, the temperature measurement accuracy of the temperature sensor determines the measurement accuracy of the lunar-based earth observation radiometer and is the core of the entire system.

[0062] Barium strontium titanate is an important ferroelectric material, due to its high dielectric constant, low optical loss, high ferroelectric activity, and large temperature coefficient near the Curie temperature. At present, this type of material not only meets the PTC characteristics, but also has a resistance value of more than 10kΩ at room temperature. At 29.7℃, the temperature coefficient of the material is greater than 1000Ω / K, and the accuracy of the thermistor can reach better than 0.01mK.

[0063] The heating plate 36 is an important component of the gallium fixed point calibration black body assembly, which determines the temperature reproduction effect of the calibration black body. The working performance of the calibration black body can be effectively improved by reasonably selecting the heating power distribution. The temperature of the gallium fixed point calibration black body assembly is controlled by using the heating plate 36. The heating plate is connected to a power supply to form a closed circuit. When the current passes through the heating plate, the resistance heating effect of the heating plate is generated, and the electrical energy is converted into thermal energy. This heating method has the characteristics of fast heating speed and high efficiency, so that the material in the crucible can be quickly heated to the required temperature, which improves the efficiency of experiments and production. The heating plate heating system cooperates with the temperature control system to achieve high-precision temperature control, keep the black body temperature within a stable range, and ensure the stability of the black body radiation value during the calibration process. The heating plate 36 is bonded to the bottom of the graphite crucible 33 through silicone rubber. The PI heating film type heating plate is simple in process and easy to install. The heating plate 36 needs to meet the control requirements and low power consumption and long life requirements of the gallium fixed point calibration black body assembly.

[0064] Metal shell, in order to enhance the overall mechanical strength of the graphite crucible and ensure the lightness and durability of the shell, can be made of stainless steel, titanium alloy or aluminum alloy. The thickness of this layer is 2mm, and through precise manufacturing process and connection method, it is ensured to be tightly combined with the internal graphite top cover 32 and the graphite crucible 33 without any gap. The main function of the metal shell 44 is to enhance the overall mechanical strength of the graphite crucible so that it can withstand greater external force and pressure.

[0065] The manufacturing process of the gallium fixed point black body 3 is as follows: the carbon nanotube array coating is deposited on the super-graphite top cover; the graphite crucible is bonded to the super-graphite top cover; the barium strontium titanate temperature sensor is pasted; the polytetrafluoroethylene protective layer and the aluminum alloy shell are made; the metal gallium is filled; and the whole is installed.

[0066] like Figure 4 As shown, the design diagram of the on-board calibration blackbody interface includes: titanium alloy screws 41, pressure plates 42, rubber rings 43, and housing 44. The super-structured gallium fixed point blackbody 3 is connected as a whole by screws 41, and the pressure plates 42 and rubber rings 43 are fixed to the metal housing 44. The metal housing is designed with external mounting holes 45 to achieve the connection between the super-structured gallium fixed point blackbody 3 and the load calibration shutter. The metal housing 44 can improve the mechanical strength of the overall structure of the gallium fixed point blackbody.

[0067] like Figure 5As shown, the working timing diagram of the wide-band superconstructor on-board calibration blackbody device of the present invention. In standby mode, the gallium fixed-point blackbody should have the ability to enter the plateau period and start calibration after 5 minutes. After entering the observation mode or the on-orbit calibration mode, first open the shutter to observe the earth or deep space. When the shutter is opened, the gallium fixed-point blackbody enters the pre-work preparation state. When the shutter is closed after 5 minutes, the gallium fixed-point blackbody is ensured to be in the plateau period. After 5 minutes, the shutter is opened again, and the gallium fixed-point blackbody enters the next pre-work preparation, and it repeats in sequence.

[0068] The wide-band super-satellite calibration blackbody device of the present invention achieves the high-precision calibration requirements of accurate, stable and precise deep space detection radiation measurement through optical design, structural design and stray light design.

[0069] This embodiment solves the requirements for the development of a high-performance calibration source with ultra-wide spectrum (0.2μm~100μm), ultra-high emissivity (emissivity ε≥99.5, @0.2μm~100μm), and on-orbit traceable temperature for the lunar-based earth radiometer for deep space exploration. It has the excellent performance of precise measurement, stable control, and accurate determination, and can meet the on-orbit calibration requirements of the deep space exploration radiometer with ultra-wide band, ultra-high emissivity, high measurement and temperature control accuracy, and traceable temperature benchmark.

[0070] A stable on-orbit radiation reference is the premise and guarantee for the on-orbit availability of a normal temperature radiometer. The present invention proposes the use of a fixed-point black body as a radiometer shutter and an optimized on-orbit working mode of the radiometer. The on-orbit radiation calibration is organically integrated with earth observation, so that each shutter-closed measurement state becomes a part of the on-orbit radiation calibration, ensuring that each earth radiation measurement result can correct the instability of the radiometer itself, and ensure high-precision measurement throughout the life cycle of the radiometer. This embodiment proposes the development technology of a calibration reference device based on a multi-means fusion of gallium metal materials + super-structured substrate materials + carbon nanotube ultra-black coatings + high-precision temperature measurement and control modules, and proposes an optimized on-orbit working mode for deep space exploration payloads. The on-orbit radiation calibration is organically integrated with earth observation, so that each calibration shutter-closed measurement state becomes a part of the on-orbit radiation calibration, ensuring that each earth radiation measurement result can correct the instability of the deep space exploration payload itself, and ensure high-precision measurement throughout the life cycle of the radiometer.

[0071] The wide-band super-structure on-board calibration blackbody device of the present invention can realize the use of the gallium fixed-point blackbody on the shutter and the deep space background as the value traceability standard under on-orbit conditions. When designing the on-board gallium fixed-point blackbody radiation source, on the one hand, it is necessary to maintain the excellent thermal conductivity between gallium and the blackbody cavity, so as to minimize the temperature gradient between gallium and the radiation surface of the blackbody cavity; on the other hand, it is necessary to provide a stable heat source for gallium melting to obtain an ideal phase change plateau; at the same time, in order to reduce the influence of environmental radiation on the radiation value of the blackbody cavity, it is necessary to maximize the emissivity of the blackbody radiation surface.

[0072] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A wide-band super-satellite calibration blackbody device, characterized in that include: A light shield (1), a calibration shutter (2), a meta-gallium fixed-point black body (3), a support frame (4), a double-layer filter (5), a multi-stage temperature control cavity (6), a detector (7), a first aperture diaphragm (81), a second aperture diaphragm (82), a field diaphragm (9), an isotope heat source (10) and a control circuit (11); wherein: The light shield (1) is arranged on the upper part of the support frame (4); The calibration shutter (2) is arranged in the middle of the support frame (4); the superstructure gallium fixed point black body (3) is installed on the calibration shutter (2); The multi-stage temperature control cavity (6) is arranged at the bottom of the support frame (4), the double-layer filter (5) and the detector (7) are both arranged in the multi-stage temperature control cavity (6), the double-layer filter (5) is located at the bottom of the meta-gallium fixed-point black body (3), and the detector (7) is located at the bottom of the double-layer filter (5); The field diaphragm (9) is arranged on the inner wall of the multi-stage temperature control cavity (6), and the field diaphragm (9) is located at the lower part of the calibration shutter (2); The first aperture diaphragm (81) and the second aperture diaphragm (82) are both arranged on the inner wall of the multi-stage temperature control cavity (6), the position of the first aperture diaphragm (81) corresponds to the position of the double-layer filter (5), and the position of the second aperture diaphragm (82) corresponds to the position of the detector (7); The isotope heat source (10) is connected to the multi-stage temperature control chamber (6); The control circuit (11) is connected to the calibration shutter (2), and the control circuit (11) is used to control the calibration shutter (2).

2. The wide-band supersatellite calibration blackbody device according to claim 1, characterized in that: The light shield (1) is used to suppress background stray light; The calibration shutter (2) is used to realize on-orbit observation of earth targets and on-orbit calibration of a deep space detection radiometer; The hypergallium fixed-point blackbody (3) is used to provide calibration reference temperature point radiation information during on-orbit radiation calibration of deep space exploration payloads; The detector (7) is used to extract radiation information of the observed earth target, cold sky background and superstructure gallium fixed point black body (3).

3. The wide-band supersatellite calibration blackbody device according to claim 1, characterized in that: The meta-gallium fixed-point black body (3) comprises a carbon nanotube array coating (31), a meta-graphite top cover (32), a graphite crucible (33), metal gallium (35), a heating plate (36), a temperature sensor (37) and a rubber ring plug (38); wherein: The carbon nanotube array coating (31) is deposited on the upper surface of the super-graphite top cover (32); The lower surface of the meta-graphite top cover (32) is glued to the graphite crucible (33) to form a hollow cylindrical shape; A pouring port is reserved at the bottom of the graphite crucible (33), and the metal gallium (35) is injected into the graphite crucible (33) through the pouring port. The pouring port of the graphite crucible (33) is bonded and sealed to the rubber ring plug (38); The temperature sensor (37) is bonded in the bottom groove of the graphite crucible (33); The heating plate (36) is connected to the bottom of the graphite crucible (33).

4. The wide-band supersatellite calibration blackbody device according to claim 3, characterized in that: The meta-gallium fixed-point black body (3) further includes a polytetrafluoroethylene protective layer (34); wherein: The lower surface of the graphite top cover (32) and the inner wall of the graphite crucible (33) are both sprayed with the polytetrafluoroethylene protective layer (34).

5. The wide-band supersatellite calibration blackbody device according to claim 1, characterized in that: The metagallium fixed-point black body (3) is mounted on the calibration shutter (2) via a connecting device.

6. The wide-band supersatellite calibration blackbody device according to claim 5, characterized in that: The connecting device comprises a screw (41), a pressing sheet (42), a rubber ring (43) and a metal shell (44); wherein: The meta-gallium fixed-point blackbody (3) is arranged in the metal shell (44); The pressing sheet (42) and the rubber ring (43) are both connected to the top of the metal shell (44) through the screw (41), and the rubber ring (43) is located between the pressing sheet (42) and the metal shell (44); The metal housing (44) is connected to the calibration shutter (2).

7. The wide-band supersatellite calibration blackbody device according to claim 1, characterized in that: The multi-stage temperature control chamber (6) comprises a primary temperature control chamber, a secondary temperature control chamber and a tertiary temperature control chamber; wherein: The primary temperature control chamber is connected to the lower part of the support frame (4); The first-stage temperature control chamber and the second-stage temperature control chamber are both connected to the third-stage temperature control chamber; The secondary temperature control chamber is located inside the primary temperature control chamber, and part of the primary temperature control chamber is located inside the secondary temperature control chamber; The double-layer filter (5) and the detector (7) are both arranged in the three-stage temperature control chamber; The field diaphragm (9), the first aperture diaphragm (81) and the second aperture diaphragm (82) are all arranged on the inner wall of the multi-stage temperature control cavity (6).

8. The wide-band supersatellite calibration blackbody device according to claim 1, characterized in that: In standby mode, the temperature of the hypergallium fixed-point black body (3) is controlled to be maintained at 29.76°C; after entering the measurement mode or the on-orbit calibration mode, the calibration shutter (2) is first opened to observe the earth or deep space. While the calibration shutter (2) is opened, the hypergallium fixed-point black body (3) is heated. When the melting temperature of metal gallium is reached, the heating is stopped, and then the metal gallium is cooled to enter the plateau period, ensuring that the plateau preparation period time Tp is within the shutter opening time period; then the calibration shutter (2) is closed, and the detector (7) measures the radiation of the hypergallium fixed-point black body (3). At this time, the metal gallium of the hypergallium fixed-point black body (3) is maintained in the plateau period, and the plateau maintenance period time Tu+plateau preparation time Tp is required to be ≥10min, so that the metal gallium is always in the plateau period when the calibration shutter (2) is closed.

9. The wide-band supersatellite calibration blackbody device according to claim 3, characterized in that: The filling amount of metal gallium accounts for 80% to 90% of the volume of the graphite crucible.

10. The wide-band supersatellite calibration blackbody device according to claim 7, characterized in that: The material of the secondary temperature control chamber is high thermal conductivity asphalt-based carbon fiber.

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