Large dynamic range, large aperture and high precision on-board blackbody radiation source and temperature control method thereof

Abstract

This application relates to the field of infrared remote sensing instrument calibration technology, and provides a high-dynamic-range, large-aperture, high-precision on-board blackbody radiation source and its temperature control method. The main body of this on-board blackbody radiation source is temperature-controlled by a refrigerator, exhibiting a large dynamic range, capable of temperature control from 200K to 310K. Through a three-layer structure consisting of the radiation source cavity, a cooling inner shell, and an outer shell, zoned temperature control via a heat transfer bracket, and a three-layer thermal insulation installation design, the temperature uniformity and stability of the blackbody radiation source are significantly improved, with temperature uniformity exceeding 30mK. Simultaneously, it possesses high emissivity (spectral emissivity reaching 0.998) and an aperture as large as 310mm, meeting the requirements for large field-of-view, long-distance use.

Description

Technical Field

[0001] This application relates to the field of infrared remote sensing instrument calibration technology, and in particular to a large dynamic range, large aperture, high precision on-board blackbody radiation source and its temperature control method. Background Technology

[0002] Onboard blackbody radiation sources are one of the key technologies for infrared remote sensing payloads, primarily used for their calibration. The stability, uniformity, and spectral emissivity of the onboard radiation source significantly impact the calibration accuracy of the infrared remote sensing payload.

[0003] Therefore, how to set up an on-board blackbody radiation source with high stability, high uniformity and high spectral emissivity is a technical problem that needs to be solved. Summary of the Invention

[0004] In view of this, this application provides a high dynamic range, large aperture, high precision on-board blackbody radiation source and its temperature control method to solve the problem that the calibration accuracy of on-board blackbody radiation sources in the prior art is limited due to narrow temperature range and insufficient uniformity.

[0005] A first aspect of the embodiments of this application provides a large dynamic range, large aperture, high precision on-board blackbody radiation source, including a radiation source body 2 and a cooler 4;

[0006] The radiation source body 2 includes an outer shell 6, a radiation source cavity 7, a cooling inner shell 8, and a heat transfer bracket 9. The radiation source cavity 7, the cooling inner shell 8, and the outer shell 6 are thermally insulated from the inside out.

[0007] The refrigeration unit 4 is connected to the refrigeration inner shell 8 to control the temperature of the refrigeration inner shell 8;

[0008] The cooling inner shell 8 is connected to the radiation source cavity 7 through a heat transfer bracket 9 to transfer the heat of the cooling inner shell 8 to the radiation source cavity 7.

[0009] A second aspect of this application provides a temperature control method for a large dynamic range, large aperture, and high precision on-board blackbody radiation source, comprising:

[0010] Configure a radiation source body 2; the radiation source body 2 includes an outer shell 6, a radiation source cavity 7, a cooling inner shell 8, and a heat transfer bracket 9, and the radiation source cavity 7, the cooling inner shell 8, and the outer shell 6 are installed with thermal insulation from the inside to the outside;

[0011] The temperature of the inner shell 8 is controlled by the refrigeration unit 4 through the heat-conducting block 10;

[0012] The heat from the cooling inner shell 8 is transferred to the radiation source cavity 7 through the heat transfer bracket 9 to achieve temperature control of the blackbody radiation source.

[0013] The beneficial effects of this application embodiment compared with the prior art are as follows: The main body of the on-board blackbody radiation source provided in this application embodiment controls the temperature through a refrigerator, which has a large dynamic range and can achieve temperature control from 200 Kelvin (K) to 310 K; Through the three-layer structure of radiation source cavity, cooling inner shell and outer shell, heat transfer bracket zoned temperature control, and three-layer structure insulation installation design, the temperature uniformity and stability of the blackbody radiation source are greatly improved, with the temperature uniformity being better than 30 millikelvin (mK); At the same time, it has a high emissivity, with a spectral emissivity of 0.998, and an aperture of up to 310 mm, which can meet the requirements of large field of view and long-distance use. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the structure of the on-board blackbody radiation source provided in the embodiments of this application.

[0016] Figure 2 This is a schematic diagram of the structure of the radiation source body provided in the embodiments of this application.

[0017] Figure 3 This is a schematic diagram of the structure of the heat transfer bracket provided in the embodiment of this application.

[0018] Figure 4 This is a schematic diagram of a heating device installed at the bottom of the radiation source cavity.

[0019] Figure 5 This is a schematic diagram of a heating device installed on the side wall of the radiation source cavity.

[0020] Figure 6 This is a schematic diagram of a heating device installed inside the refrigeration shell.

[0021] Figure 7 This is a schematic diagram of a thermometer installed at the bottom of the radiation source cavity.

[0022] Figure 8 This is a schematic diagram of a thermometer installed on the side wall of the radiation source cavity.

[0023] Figure 9 This is a schematic diagram of a thermometer installed on the side wall of the refrigeration inner shell.

[0024] Figure 10 This is a schematic diagram of a thermometer installed at the bottom of the refrigeration inner shell.

[0025] Figure 11 This is a schematic diagram of a thermometer mounted on the side wall of the casing.

[0026] Figure 12 This is a schematic diagram of a thermometer mounted on the bottom of the casing.

[0027] Figure 13 This is a flowchart illustrating the temperature control method for a large dynamic range, large aperture, and high precision on-board blackbody radiation source provided in this application embodiment.

[0028] Among them, 1-light blocking plate; 2-radiation source body; 3-main body support; 4-refrigeration unit; 5-controller; 6-outer shell; 7-radiation source cavity; 8-refrigeration inner shell; 9-heat transfer support; 10-heat conduction block; 11-bottom of radiation source cavity; 12-sub-support I; 13-sub-support II; 14-sub-support III; 15-sub-support IV; Detailed Implementation

[0029] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0030] The following will describe in detail, with reference to the accompanying drawings, an embodiment of the present application of a high dynamic range, large aperture, high precision on-board blackbody radiation source and its temperature control method.

[0031] As mentioned above, how to set up an on-board blackbody radiation source with high stability, high uniformity and high spectral emissivity is a technical problem that needs to be solved.

[0032] In view of this, this application provides a high-dynamic-range, large-aperture, high-precision on-board blackbody radiation source. The main body of the on-board blackbody radiation source is temperature-controlled by a refrigerator, which has a large dynamic range and can achieve temperature control from 200K to 310K. Through a three-layer structure consisting of a radiation source cavity, a cooling inner shell, and an outer shell, zoned temperature control of the heat transfer bracket, and a three-layer thermal insulation installation design, the temperature uniformity and stability of the blackbody radiation source are greatly improved, with temperature uniformity better than 30mK. At the same time, it has a high emissivity, with a spectral emissivity of 0.998, and an aperture of up to 310mm, which can meet the requirements for long-distance use with a large field of view.

[0033] Example 1

[0034] Figure 1 and Figure 2 This illustration shows a high-dynamic-range, large-aperture, high-precision on-board blackbody radiation source provided in an embodiment of this application. (Reference) Figure 1 and Figure 2 The blackbody radiation source on this satellite includes a main body 2 and a cooler 4. Furthermore, the blackbody radiation source can be mounted on the main support 3.

[0035] The radiation source body 2 includes an outer shell 6, a radiation source cavity 7, a cooling inner shell 8, and a heat transfer bracket 9. The radiation source cavity 7, the cooling inner shell 8, and the outer shell 6 are insulated from the inside out.

[0036] The outer shell 6 serves as a support. Furthermore, since the external heat flow of spaceborne instruments varies considerably, the outer shell 6 can also be used to reduce the impact of these variations on the temperature uniformity of the radiation source cavity 7.

[0037] The refrigeration unit 4 is connected to the refrigeration inner shell 8 to control the temperature of the refrigeration inner shell 8.

[0038] The cooling inner shell 8 is connected to the radiation source cavity 7 through a heat transfer bracket 9 to transfer the heat of the cooling inner shell 8 to the radiation source cavity 7.

[0039] Further reference Figure 3 The heat transfer bracket 9 includes sub-bracket I 12, sub-bracket II 13, sub-bracket III 14 and sub-bracket IV 15.

[0040] Among them, sub-support I12 and sub-support IV15 are non-metallic material supports, while sub-support II13 and sub-support III14 are metallic material supports.

[0041] Each sub-support surface is fitted with a heating device, and the outer surfaces of the cooling inner shell 8 and the radiation source cavity 7 are also fitted with heating devices to achieve temperature control. Each sub-support is independently controlled and transfers heat to different areas of the radiation source cavity 7.

[0042] In some embodiments of this application, the radiation source cavity 7 may include a bottom 11 and sidewalls, wherein the bottom 11 is a square pyramid structure.

[0043] Among them, M miniature phase change fixing points are installed on the outer surface of the bottom 11 of the radiation source cavity 7, and the M miniature phase change fixing points are used to mount N thermometers.

[0044] N thermometers are installed on the sidewall of the radiation source cavity 7; N and M are both positive integers greater than 1, and N is greater than or equal to M. In one example, the thermometers can be platinum resistance thermometers.

[0045] The inner surface of the bottom 11 of the radiation source cavity 7 can be coated with a high emissivity blackbody to increase emissivity while reducing the length of the on-board blackbody radiation source.

[0046] In other words, the on-board blackbody radiation source body provided in this application embodiment may include an outer shell, a radiation source cavity, a cooling inner shell, and a heat transfer support, with the installation sequence being the radiation source cavity, heat transfer support, cooling inner shell, and outer shell. The outer shell, radiation source cavity, and cooling inner shell are thermally insulated from each other. This three-layer shell design can improve the temperature uniformity and temperature stability of the blackbody.

[0047] Based on blackbody design specifications and emissivity requirements, the radiation source cavity adopts a cavity design, consisting of two parts: sidewalls and a bottom. The bottom features a square pyramid design, with four micro-phase transition fixing point mounting slots on its reverse side (outer surface). After the sidewalls and bottom are fixed together, the inner surface can be coated with high-emissivity black paint. In one example, the spectral emissivity of the radiation source cavity after black paint coating was tested, yielding a result of 0.998.

[0048] The thermal design of the entire on-board blackbody radiation source can also be carried out based on the requirements for temperature uniformity and stability of the on-board blackbody radiation source.

[0049] In some implementations, heating elements can be attached to the outer surfaces of the cooling inner shell and the radiation source cavity. Five platinum resistance thermometers and four miniature phase-change fixing points can be mounted on the bottom of the radiation source cavity, each containing a platinum resistance thermometer. Three to four platinum resistance thermometers can be installed on the sidewalls of the radiation source cavity for temperature measurement and control. The miniature phase-change fixing points calibrate the resistance values ​​of the platinum resistance thermometers through phase changes, thereby ensuring the long-term reliable operation of the instrument in orbit.

[0050] The cooling inner shell and the radiation source cavity can be designed for radiation temperature equalization through a heat transfer bracket.

[0051] Because the radiation source cavity has a large diameter, this embodiment employs a design with independent temperature control in different zones using heat transfer supports to ensure temperature uniformity within the cavity. The heat transfer supports can include four parts: sub-support I, sub-support II, sub-support III, and sub-support IV. Sub-support I and sub-support IV are made of non-metallic materials, while sub-support II and sub-support III are made of metallic materials. Heating devices, such as heating elements or heating films, are attached to the surfaces of all four sub-supports for temperature control.

[0052] Five platinum resistance thermometers mounted on the bottom of the radiation source cavity monitor the temperature of each area in real time. Based on the detected temperature, the controller 5 controls the heating amplitude of the heating device in the heat transfer bracket to ensure that the temperature detected by the five platinum resistance thermometers is consistent, thereby ensuring the temperature uniformity of the radiation source cavity.

[0053] Figure 4 The various heating devices installed at the bottom of the radiation source cavity are shown. Figure 5 The various heating devices installed on the sidewall of the radiation source cavity are shown. Figure 6 The various heating devices installed within the refrigeration housing are shown. Figures 4 to 6 The distribution of heating devices on the bottom, side walls, and inner cooling shell of the radiation source cavity can be observed. One heating device can be installed in each heating area. This method of installing heating devices allows for independent temperature control of different zones within the radiation source cavity.

[0054] Figure 7 The thermometers installed at the bottom of the radiation source cavity are shown. Figure 8 The thermometers mounted on the sidewall of the radiation source cavity are shown. Figure 9 The thermometers mounted on the side wall of the refrigeration inner shell are shown. Figure 10 The thermometers installed at the bottom of the refrigeration housing are shown. Figure 11 The thermometers mounted on the side wall of the housing are shown. Figure 12 The thermometers mounted on the bottom of the housing are shown. Figures 7 to 12 As can be seen, the temperature of different heating zones can be monitored in real time using thermometers installed in those zones. K1 to K10 represent different platinum resistance thermometers. K10 can also be achieved using miniature phase transition points. C11 to C17 represent different miniature phase transition points.

[0055] In some embodiments of this application, the refrigerator 4 can be connected to the cooling inner shell 8 via a heat-conducting block 10 to achieve temperature control of 200K~310K for the cooling inner shell 8.

[0056] In other words, the refrigerator is connected to the cooling inner shell through a heat-conducting block to control the temperature of the cooling inner shell. Through radiation heat dissipation, it can achieve temperature control of 200K~310K, enabling the on-board blackbody radiation source to have a large dynamic range.

[0057] When the radiation source cavity is expected to operate at 200K, the refrigerator can be turned on first to cool the inner shell at 180K~195K, and then the inner shell can perform single-stage radiation and heat conduction cooling on the radiation source cavity.

[0058] When the radiation source cavity is expected to operate at a higher temperature, from 200K to a maximum of 310K, the refrigerator can be shut down. Two-stage radiation temperature control of the blackbody radiation source cavity, achieved through both the outer shell and the inner cooling shell, helps reduce uneven heat flow caused by temperature differences within the inner shell. Compared to direct temperature control of the blackbody radiation source cavity, this improves temperature uniformity. Thermal insulation design between the multi-layered structure reduces heat leakage from the refrigerator and eliminates interference between the outer shell, inner shell, and radiation source cavity.

[0059] In some embodiments of this application, the onboard blackbody radiation source may further include a light-blocking plate 1. The light-blocking plate 1 closes during the phase transition at the micro-phase transition fixed point and opens via motor control when the onboard instruments scan the blackbody radiation source, to ensure the stability of the phase transition temperature.

[0060] To verify the performance indicators of the on-board blackbody radiation source provided in this application embodiment, an on-board blackbody radiation source experiment was conducted in a liquid nitrogen environment within a vacuum tank. The cooling temperature of the on-board blackbody radiation source was controlled using a refrigerator, achieving dynamic temperature control within a range of 200K to 310K. During the dynamic temperature control process, the temperature uniformity and stability of the on-board blackbody radiation source were measured, with the temperature uniformity exceeding 30mK.

[0061] Example 2

[0062] Figure 13 The flowchart illustrates the temperature control method for a large dynamic range, large aperture, and high precision on-board blackbody radiation source provided in an embodiment of this application. For example... Figure 13 As shown, the method includes the following steps:

[0063] In step S1301, the radiation source body is configured.

[0064] The radiation source body includes an outer shell, a radiation source cavity, a cooling inner shell, and a heat transfer bracket. The radiation source cavity, the cooling inner shell, and the outer shell are insulated from the inside out.

[0065] In step S1302, a refrigeration unit is used to control the temperature of the refrigeration inner shell through a heat-conducting block.

[0066] In step S1303, the heat from the cooling inner shell is transferred to the radiation source cavity through the heat transfer bracket to achieve temperature control of the blackbody radiation source.

[0067] According to the embodiments of this application, the main body of the on-board blackbody radiation source is temperature-controlled by a refrigerator, which has a large dynamic range and can achieve temperature control from 200K to 310K. Through the three-layer structure of the radiation source cavity, the inner shell and the outer shell, the heat transfer bracket for zoned temperature control, and the three-layer structure for heat insulation installation, the temperature uniformity and stability of the blackbody radiation source are greatly improved, with the temperature uniformity being better than 30mK. At the same time, it has a high emissivity, with a spectral emissivity of 0.998, and an aperture of up to 310mm, which can meet the requirements for long-distance use with a large field of view.

[0068] In some embodiments of this application, the heat transfer support includes sub-support I, sub-support II, sub-support III and sub-support IV.

[0069] Among them, sub-support I and sub-support IV are non-metallic material supports, while sub-support II and sub-support III are metallic material supports.

[0070] Each sub-support surface is fitted with a heating device, and the outer surfaces of the cooling inner shell and the radiation source cavity are also fitted with heating devices to achieve temperature control.

[0071] Each sub-support is independently controlled and transfers heat to different areas of the radiation source cavity.

[0072] The radiation source cavity includes a bottom and side walls, with the bottom being a four-sided pyramidal structure.

[0073] M miniature phase change fixing points are installed on the bottom outer surface of the radiation source cavity. These M miniature phase change fixing points are used to mount N thermometers.

[0074] N thermometers are installed on the side wall of the radiation source cavity; N and M are both positive integers greater than 1, and N is greater than or equal to M.

[0075] All of the above-mentioned optional technical solutions can be combined in any way to form the optional embodiments of this application, and will not be described in detail here.

[0076] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A high-dynamic-range, large-aperture, high-precision on-board blackbody radiation source, characterized in that, It includes the radiation source body (2) and the refrigerator (4); The radiation source body (2) includes an outer shell (6), a radiation source cavity (7), a cooling inner shell (8), and a heat transfer bracket (9). The radiation source cavity (7), the cooling inner shell (8), and the outer shell (6) are installed in an insulated manner from the inside to the outside. The refrigeration unit (4) is connected to the refrigeration inner shell (8) to control the temperature of the refrigeration inner shell (8); The cooling inner shell (8) is connected to the radiation source cavity (7) through a heat transfer bracket (9) to transfer the heat of the cooling inner shell (8) to the radiation source cavity (7).

2. The high-dynamic-range, large-aperture, high-precision on-board blackbody radiation source according to claim 1, characterized in that, The heat transfer support (9) includes sub-support I (12), sub-support II (13), sub-support III (14) and sub-support IV (15); Among them, sub-support I (12) and sub-support IV (15) are non-metallic material supports, and sub-support II (13) and sub-support III (14) are metallic material supports; Each sub-support surface is fitted with a heating device, and the outer surfaces of the cooling inner shell (8) and the radiation source cavity (7) are also fitted with heating devices to achieve temperature control.

3. The high-dynamic-range, large-aperture, high-precision on-board blackbody radiation source according to claim 2, characterized in that, Each sub-support is independently controlled and transfers heat to different areas of the radiation source cavity (7).

4. The large dynamic range, large aperture, high precision on-board blackbody radiation source according to claim 1, characterized in that, The radiation source cavity (7) includes a bottom (11) and sidewalls, and the bottom (11) is a square pyramid structure; M micro phase change fixing points are installed on the outer surface of the bottom (11) of the radiation source cavity (7), and the M micro phase change fixing points are used to attach N thermometers; N thermometers are installed on the side wall of the radiation source cavity (7); N and M are both positive integers greater than 1, and N is greater than or equal to M.

5. The large dynamic range, large aperture, high precision on-board blackbody radiation source according to claim 4, characterized in that, The bottom (11) inner surface of the radiation source cavity (7) is coated with a high emissivity blackbody to increase emissivity while reducing the length of the on-board blackbody radiation source.

6. The high-dynamic-range, large-aperture, high-precision on-board blackbody radiation source according to claim 1, characterized in that, The refrigerator (4) is connected to the refrigeration shell (8) through a heat-conducting block (10) to achieve temperature control of 200K~310K for the refrigeration shell (8).

7. The large dynamic range, large aperture, high precision on-board blackbody radiation source according to claim 4 or 5, characterized in that, The on-board blackbody radiation source also includes a light-blocking plate (1). The light-blocking plate (1) closes during the phase transition at the micro phase transition fixed point and opens under motor control when the spaceborne instrument scans the blackbody radiation source, so as to ensure the stability of the phase transition temperature.

8. A method for temperature control of a large dynamic range, large aperture, and high precision on-board blackbody radiation source, characterized in that, include: Configure a radiation source body (2); the radiation source body (2) includes an outer shell (6), a radiation source cavity (7), a cooling inner shell (8) and a heat transfer bracket (9), and the radiation source cavity (7), the cooling inner shell (8) and the outer shell (6) are heat-insulated from the inside to the outside; The temperature of the cooling inner shell (8) is controlled by a refrigeration unit (4) through a heat-conducting block (10); The heat from the cooling inner shell (8) is transferred to the radiation source cavity (7) through the heat transfer bracket (9) to achieve temperature control of the blackbody radiation source.

9. The temperature control method for a large dynamic range, large aperture, high precision on-board blackbody radiation source according to claim 8, characterized in that, The heat transfer support (9) includes sub-support I (12), sub-support II (13), sub-support III (14) and sub-support IV (15); Among them, sub-support I (12) and sub-support IV (15) are non-metallic material supports, and sub-support II (13) and sub-support III (14) are metallic material supports; Heating devices are attached to the surface of each sub-support, and heating devices are attached to the outer surfaces of the cooling inner shell (8) and the radiation source cavity (7) to achieve temperature control; Each sub-support is independently controlled and transfers heat to different areas of the radiation source cavity (7).

10. The temperature control method for a large dynamic range, large aperture, high precision on-board blackbody radiation source according to claim 8, characterized in that, The radiation source cavity (7) includes a bottom and sidewalls, with the bottom being a square pyramid structure; M micro phase change fixing points are installed on the bottom outer surface of the radiation source cavity (7), and the M micro phase change fixing points are used to attach N thermometers; N thermometers are installed on the side wall of the radiation source cavity (7); N and M are both positive integers greater than 1, and N is greater than or equal to M.

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