A multi-stage on-board calibration device for improving calibration speed

Abstract

This invention relates to a multi-stage on-board calibration device for improving calibration speed, comprising a blackbody, a controller, a temperature control element, a temperature sensor, a rope, a mounting plate with corner fixing seats and a fixed cylinder, limiting blocks, rubber pads, a motor, and a transmission mechanism, comprising multiple layers. The rope passes through through holes in four protrusions of the blackbody and then connects to the four corner fixing seats on the mounting plate. After being taut, the rope is finally wrapped around the fixed cylinder and secured with adhesive. Four limiting blocks are fixed above the four protrusions of the blackbody, confining the blackbody between the limiting blocks and the mounting plate. A flexible pad is locally placed on the side of the limiting blocks and the mounting plate facing the blackbody. The temperature control element and a high-precision temperature sensor are attached to the back of the blackbody. The temperature sensor and temperature control element are controlled by the controller for multi-stage temperature control. The entire back of the blackbody is covered with a multi-layer thermal insulation (MLI) assembly for radiative thermal insulation. The controller controls the operation of the motor and transmission structure to control the blackbody's optical path entry and exit. This invention features good temperature uniformity, fast switching speed between multi-stage calibration temperatures, wide calibration range, light weight, and small size.

Description

Technical Field

[0001] This invention relates to a multi-stage on-board calibration device for improving calibration speed, belonging to the field of temperature control technology, and is particularly suitable for the design of multi-stage on-board infrared calibration blackbody devices with large area and high temperature uniformity requirements. Background Technology

[0002] After a spaceborne infrared camera is launched into orbit, its performance changes due to factors such as the space environment and its own aging. Furthermore, the non-uniformity of response of each detector element and its time-varying characteristics affect image quality. Without on-orbit radiometric calibration, image applications will be affected. There are many on-orbit calibration methods, including cross-calibration, substitution calibration, and half-optical and full-optical calibration. Each method has its advantages and limitations. For large-aperture infrared cameras, half-optical calibration is typically used, employing a blackbody placed inside the camera as the radiation source for on-board radiometric calibration. Moreover, research by Ma Wenpo et al. shows that blackbody calibration at a fixed temperature point limits its calibrable temperature range, resulting in lower radiometric calibration accuracy and failing to meet users' increasingly stringent quantitative data requirements. Therefore, blackbody calibration generally requires multiple stages of calibration.

[0003] The temperature uniformity requirements for spaceborne infrared calibration blackbodies are very high, generally requiring a uniformity better than ±0.1℃. See the literature "A Review of the Development of Radiometric Calibration Technology for Spaceborne Infrared Remote Sensing Cameras". As the aperture of remote sensors increases, the area of ​​the internal calibration blackbody also increases, and the difficulty of achieving blackbody temperature uniformity also increases accordingly, mainly in the following aspects: 1) Large blackbody mass; as the blackbody area increases, in order to meet the blackbody temperature uniformity requirements, the thickness of the blackbody also increases, and thus the mass also increases. Wang Qiang et al. [Optimization Design and Evaluation of Temperature Uniformity of Blackbody with Microcavity Surface] designed a 100mm diameter copper blackbody with a temperature uniformity better than 0.1℃, and its thickness exceeded 5mm. 2) Blackbodies are large. To meet the high temperature uniformity requirements of large-diameter blackbodies, thick thermal insulation pads are needed to insulate the blackbodies from their mounting structures. The blackbodies in "Research on Calibration Heat Sources of Spaceborne Microwave Radiometers" are fixed with thermal insulation materials and screws, which increases the size of the blackbodies. A larger blackbodies require larger openings in the optical path, thus impacting the optical path design. 3) Blackbody calibration is slow. Larger blackbodies have higher heat capacities, leading to longer heating and cooling times during multi-stage calibration. This longer time results in poor usability and low usage frequency for multi-stage calibrated blackbodies.

[0004] The above analysis shows that traditional calibration blackbody designs have drawbacks such as poor temperature uniformity, large mass, large volume, and slow calibration speed. These limitations make it difficult to meet the development needs of large-aperture on-board calibration blackbody designs. Summary of the Invention

[0005] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a multi-stage on-board calibration blackbody device with good temperature uniformity, fast switching speed between different temperatures, wide calibration range, light weight, and small size.

[0006] The technical solution of the present invention is: a multi-stage on-board calibration device for improving calibration speed, the device comprising a blackbody, a controller, a temperature control element, a temperature sensor, a rope, a mounting plate, a motor, and a transmission mechanism;

[0007] The blackbody is suspended and fixed to the mounting plate by ropes. Temperature control elements and temperature sensors are attached to the back of the blackbody, and the entire blackbody is covered with multi-layer heat insulation components for radiative heat insulation. The mounting plate is fixedly installed on the transmission mechanism, and the motor is used to drive the movement of the transmission mechanism.

[0008] When the spaceborne infrared camera images the target, the motor rotates forward to drive the transmission mechanism to place the blackbody outside the optical path of the spaceborne infrared camera. When performing on-board radiometric calibration, the controller controls the blackbody to a preset temperature through the temperature control element based on the temperature collected by the temperature sensor. Then the controller controls the motor to rotate in reverse, driving the transmission mechanism to cut into the optical path with the blackbody. After completing the on-board radiometric calibration, the blackbody is moved out of the optical path.

[0009] Preferably, the blackbody is rectangular, with a boss on each side extending outwards, and a through hole parallel to the side length in the middle of the boss; a fixing seat and a fixing cylinder are provided on the mounting plate plane, the fixing seat is an arc-shaped column structure with a groove in the middle; the blackbody is placed on the mounting plate, and the fixing seat is located at one corner of the blackbody;

[0010] The rope first wraps around the groove of the first fixing seat on the mounting plate, passes through the through hole in the first boss on the black body, then wraps around the groove of the second fixing seat on the mounting plate, passes through the through hole in the second boss on the black body, then wraps around the groove of the third fixing seat on the mounting plate, passes through the through hole in the third boss on the black body, then wraps around the groove of the fourth fixing seat on the mounting plate, passes through the through hole in the fourth boss on the black body, and finally, after the two ends of the rope are tightened, they are respectively wrapped around two fixing cylinders and fixed with glue.

[0011] Preferably, the multi-stage on-board calibration device for improving calibration speed further includes a limiting block, and a limiting seat is provided on the mounting plate. The limiting block is installed on the limiting seat of the mounting plate, and the limiting block is located above the protrusions of the blackbody, restricting the blackbody between the limiting block and the mounting plate.

[0012] Preferably, a flexible gasket is provided locally on both the limiting block and the mounting plate facing the blackbody side.

[0013] Preferably, the limiting block is made of aluminum alloy, and the flexible gasket is preferably a silicone rubber gasket or a rubber gasket.

[0014] Preferably, the blackbody is made of copper and has a V-groove on its front side. The back of the blackbody has reinforcing ribs, on which the temperature sensor is attached, and the temperature control element is positioned away from the reinforcing ribs.

[0015] Preferably, the temperature control element is a heating element or a cooling element. If the ambient temperature is lower than the preset temperature of the blackbody, a heating element is attached to the back of the blackbody. If the ambient temperature is higher than the preset temperature of the blackbody, a cooling element is attached to the back of the blackbody.

[0016] Preferably, the temperature sensor is a platinum resistance temperature sensor.

[0017] Preferably, the motor is a stepper motor, and the transmission mechanism is a gear transmission mechanism.

[0018] Preferably, the rope used is a polyimide rope or a glass fiber rope.

[0019] The advantages of this invention compared to the prior art are:

[0020] (1) The blackbody of the present invention is suspended and fixed by rope, and the total thermal resistance between the blackbody and the mounting plate reaches more than 10,000℃ / W. The thermal leakage can be ignored, and the temperature uniformity of the blackbody is good.

[0021] (2) In this invention, a rope is passed through the through hole in the blackbody boss and connected to the corner retainer on the mounting plate. This ensures that there is a sufficiently long heat conduction and heat transfer distance between the blackbody and the mounting plate. It also ensures that the blackbody assembly has a small size in the optical path direction, i.e., in the direction perpendicular to the blackbody surface, which facilitates the entry and exit of the blackbody into and out of the optical path.

[0022] (3) Under the same temperature uniformity index, the blackbody of the present invention is thinner, lighter, and has a smaller heat capacity. The heating and cooling time during multi-level calibration of the blackbody is shorter, and the calibration range is wider.

[0023] (4) The present invention combines rope pulling and fixing with limiting block limiting, which ensures that the mechanical properties of the blackbody assembly meet the mechanical environment requirements of rocket launch, and also ensures that the overall size of the blackbody assembly in the optical path direction is small, thus having little impact on the optical path design. Attached Figure Description

[0024] Figure 1(a) is a black body back view in an embodiment of the present invention;

[0025] Figure 1(b) is a front view of the boldface in an embodiment of the present invention;

[0026] Figure 1(c) is a bold side view of an embodiment of the present invention;

[0027] Figure 1(d) is a partial enlarged view of the boldface figure 1(c) in an embodiment of the present invention;

[0028] Figure 2(a) is a top view of the mounting plate structure in an embodiment of the present invention;

[0029] Figure 2(b) is a side view of the mounting plate structure in an embodiment of the present invention;

[0030] Figure 3(a) is a schematic diagram of the structure of the blackbody component assembly in an embodiment of the present invention;

[0031] Figure 3(b) is a cross-sectional view of the blackbody component assembly in an embodiment of the present invention;

[0032] Figure 3(c) is a partial enlarged view of Figure 3(b) in an embodiment of the present invention;

[0033] Figure 4 This is a general structural diagram of the calibration device according to an embodiment of the present invention;

[0034] Figure 5 This is a temperature field cloud diagram of a blackbody calibrated at 345K in an embodiment of the present invention;

[0035] Figure 6 This is a temperature field cloud map of a blackbody calibrated at 300K in an embodiment of the present invention;

[0036] Figure 7 This is a temperature field contour plot of a blackbody calibrated at 345 K in Comparative Example 2 of this invention; Detailed Implementation

[0037] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0038] like Figure 4 As shown, the present invention provides a multi-stage on-board calibration device for improving calibration speed, comprising a blackbody 1, a controller 10, a temperature control element 2, a temperature sensor 3, a rope 7, a mounting plate 4, a motor 11, and a transmission mechanism 12; the temperature control element and the temperature sensor are arranged on the back of the blackbody, and the two are connected to the controller, thereby realizing multi-stage temperature control of the blackbody through the controller.

[0039] The blackbody 1 is suspended and fixed to the mounting plate 4 by rope 7. The temperature control element 2 and temperature sensor 3 are pasted on the back of the blackbody 2, and the whole body is covered with a multi-layer heat insulation structure 13 for radiation heat insulation. The mounting plate 4 is fixedly installed on the transmission mechanism 12, and the motor is used to drive the transmission mechanism 12 to move.

[0040] When the spaceborne infrared camera images the target, the motor 1 rotates forward to drive the transmission mechanism 12 to place the blackbody 1 outside the optical path of the spaceborne infrared camera. When performing on-board radiometric calibration, the controller 10 controls the blackbody 1 to a preset temperature through the temperature control element 2 based on the temperature collected by the temperature sensor 3. Then, the controller 10 controls the motor to rotate in reverse, driving the transmission mechanism 12 to cut into the optical path with the blackbody 1. After completing the on-board radiometric calibration, the blackbody 1 is moved out of the optical path.

[0041] like Figures 1(a) to 1(d) As shown, the black body 1 is rectangular, with a boss on each side extending outwards, and a through hole parallel to the side length in the middle of the boss; the mounting plate 4 has 4 fixing seats 5 and a pair of fixing cylinders 6 on its plane, the fixing seats 5 are arc-shaped cylinder structures with a groove in the middle; the black body 1 is placed on the mounting plate 4, and the 4 fixing seats 5 are located at the 4 corners of the black body.

[0042] The rope 7 first wraps around the groove of the first fixing seat 5 on the mounting plate, passes through the through hole in the first boss on the black body 1, then wraps around the groove of the second fixing seat 5 on the mounting plate, passes through the through hole in the second boss on the black body 1, then wraps around the groove of the third fixing seat 5 on the mounting plate, passes through the through hole in the third boss on the black body 1, then wraps around the groove of the fourth fixing seat 5 on the mounting plate, passes through the through hole in the fourth boss on the black body 1, and finally, after the two ends of the rope 7 are tightened, they are respectively wrapped around the two fixing cylinders 6 and fixed with glue.

[0043] This invention employs a rope that passes through a through-hole in the blackbody boss and is connected and fixed to an angle retainer on the mounting plate. This ensures a sufficiently long thermal conduction distance between the blackbody and the mounting plate, while also ensuring that the blackbody assembly has a small size in the optical path direction, i.e., the direction perpendicular to the blackbody surface, facilitating the entry and exit of the blackbody into and out of the optical path.

[0044] The multi-stage on-board calibration device is characterized by further comprising four limiting blocks 8, and four limiting seats provided on the mounting plate. The limiting blocks 8 are mounted on the limiting seats of the mounting plate by screws. The four limiting blocks 8 are located above the four protrusions of the blackbody 1, restricting the blackbody 1 between the limiting blocks 8 and the mounting plate 4. A flexible gasket 9 is partially provided on the side of the limiting blocks 8 and the mounting plate 4 facing the blackbody 1.

[0045] This invention limits the movement range of the blackbody by using a limiting seat and a flexible pad, ensuring that the blackbody is not damaged during rocket launch vibrations.

[0046] Preferably, the blackbody is made of a material with a thermal conductivity greater than 180 W / (mK). The surface of the blackbody facing the detector is the front side, with a V-groove and painted black. A temperature control element and a temperature sensor are mounted on the back side of the blackbody. The temperature control element mainly includes a heating element or a cooling element. The heating element can be a thin-film heater, while the cooling element can be a thermoelectric cooler. If the ambient temperature is lower than the preset temperature of the blackbody, a thin-film heater is attached to the back side of the blackbody, and the heater is designed according to the shape of the blackbody to cover as much of the back side as possible. If the ambient temperature is higher than the preset temperature of the blackbody, a thermoelectric cooler is attached to the back side of the blackbody. The temperature sensor is preferably a Pt1000 platinum resistance thermometer with a temperature measurement accuracy better than ±0.01℃. The temperature sensor 3 is attached to a reinforcing rib, and the temperature control element avoids the location of the reinforcing rib.

[0047] The rope is preferably a polyimide rope with poor thermal conductivity but meeting mechanical performance requirements, or a fiberglass rope. The mounting plate is preferably an aluminum alloy plate, the limiting block is preferably an aluminum alloy block, and the flexible gasket is preferably a silicone rubber gasket or a rubber gasket to ensure that the blackbody and mounting plate are not damaged during rocket launch vibrations. The motor is preferably a stepper motor, and the transmission mechanism is preferably a gear transmission structure.

[0048] Example:

[0049] The blackbody is rectangular, measuring 110mm × 130mm (see Figure 1). It is required to have a temperature uniformity better than 0.1℃ and a stability better than ±0.1℃ / 30min. Taking an ambient temperature of 20℃, lower than the blackbody's multi-level calibration temperatures (300K, 320K, 345K), as an example, the blackbody assembly is designed as follows: As shown in Figure 1, blackbody 1 is made of T4 copper with excellent thermal conductivity and low heat capacity. The back of the blackbody has ribs, and the front has V-grooves. The front of the blackbody is painted black. A thin-film electric heater 2, approximately 0.1mm thick, is bonded to the back of blackbody 1 using silicone rubber. Except for the four reinforcing ribs, the electric heater covers the entire back of the blackbody. Two of the thicker reinforcing ribs on the back of blackbody 1 each have a circular hole for attaching two cylindrical temperature sensors 3. The temperature sensors 3 and the electric heater 2 are temperature-controlled using a PID algorithm in controller 10. The back of the blackbody 1 is entirely covered with 10 low-temperature multilayer thermal insulation components 13 for radiative thermal insulation. There is a boss in the middle of each side of the blackbody, for a total of 4 bosses on the 4 sides. Each boss has a through hole of about 1.5mm in diameter in the center for threading.

[0050] As shown in Figures 2(a) and 2(b), the mounting plate 4 is machined with four corner fixing seats 5 for fixing the rope, two fixing cylinders 6 for finally applying adhesive to fix the rope, and four sets of mounting holes for fixing the limiting blocks. As shown in Figures 3(a) to (c), the rope 7 first wraps around the groove of the first fixing seat 5 on the mounting plate, passes through the through hole in the first boss on the black body 1, then wraps around the groove of the second fixing seat 5 on the mounting plate, passes through the through hole in the second boss on the black body 1, then wraps around the groove of the third fixing seat 5 on the mounting plate, passes through the through hole in the third boss on the black body 1, then wraps around the groove of the fourth fixing seat 5 on the mounting plate, passes through the through hole in the fourth boss on the black body 1, and finally, after the two ends of the rope 7 are tightened, they are respectively wrapped around the two fixing cylinders 6 and fixed with adhesive. Four limiting blocks 8 are fixed above the four protrusions of the blackbody 1, confining the blackbody protrusions between the limiting blocks and the mounting plate. A flexible gasket 9 is locally placed on the side of the limiting blocks and the mounting plate facing the blackbody. The distance between the blackbody protrusions and the upper and lower gaskets is approximately 0.2 mm to ensure that the blackbody assembly will not be damaged during rocket launch vibration. When performing on-board radiometric calibration, the controller 10 controls the temperature control element to control the blackbody 1 to the preset temperature. Then, the controller controls the motor and transmission mechanism 11 to drive the blackbody assembly into the optical path, and after completing the on-board radiometric calibration, it moves out of the optical path.

[0051] In the above specific embodiment, the blackbody 1 is preferably made of T4 copper. The blackbody has a V-groove on its front side and is coated with black paint. The measured emissivity reaches 0.97, and the average thickness of the blackbody is only 1.4 mm. The blackbody weighs only 209 g and has a heat capacity of only 73 J / ℃. The temperature sensor 3 is preferably a 4-wire Pt1000 platinum resistance temperature sensor with a calibration accuracy better than ±0.01℃. The controller 10 uses a high-precision temperature control device with a temperature acquisition system capability better than ±0.01℃. The multi-layer thermal insulation component 13 is composed of alternating layers of low-emissivity reflective screens and low-thermal-conductivity insulating layers, with each layer of reflective screen and insulating layer forming a unit. Preferably, a 10-unit low-temperature thermal insulation multi-layer component has an equivalent emissivity of less than 0.03.

[0052] The rope 7 is preferably a 1mm diameter polyimide rope or fiberglass rope, and the flexible gasket 9 is preferably a silicone rubber gasket. The limiting block is preferably made of aluminum alloy, with a total height of only 5.5mm. The mounting plate is preferably made of aluminum alloy with a thickness of 4mm. The total thickness of the blackbody and its fixing components is only 9.5mm, resulting in a small volume that facilitates the entry and exit of the blackbody into the optical path. The motor 11 is preferably a stepper motor, and the transmission mechanism 12 is preferably a gear transmission mechanism 12. The blackbody assembly is mounted on the gear transmission mechanism 12. When the motor 11 rotates forward, the gear transmission mechanism 12 sends the blackbody 1 into the optical path; when the motor 11 rotates in reverse, the gear transmission mechanism 12 sends the blackbody assembly out of the optical path. See Figure 4 .

[0053] A total of 8 rope segments connect the blackbody 1 to the four corner fixing bases 5. The total thermal resistance is the parallel value of the thermal resistance of these 8 rope segments. As shown in Figure 3, 4 rope segments are 46 mm long, and the other 4 are 57 mm long. The formula for calculating the thermal resistance is as follows; δ - rope length (mm), A - rope cross-sectional area (1mm diameter), λ - rope thermal conductivity (0.4 W / mK for polyimide rope). Therefore, the total thermal resistance R of the 8 parallel rope segments is 20267℃ / W. Based on the principle that total heat loss equals temperature difference divided by total thermal resistance, even if the temperature difference between the blackbody and the corner mount is 100℃, the total heat loss between them is only 0.005 W.

[0054] Because the blackbody of this invention has low thermal conductivity and heat leakage, when the ambient temperature is 20°C (293.15 K) and the blackbody is calibrated to a maximum temperature of 345 K, the time it takes for the blackbody to heat up from 293.15 K to 345 K is approximately 360 s. The temperature field of the blackbody near 345 K is shown in [the figure]. Figure 5 The maximum temperature difference is 0.09 K. Because there are no electric heaters at the ribs on the back of the blackbody, the temperature field is not strictly centrosymmetric. The blackbody takes 1668 s to cool from its highest rated temperature of 345 K to its lowest rated temperature of 300 K, at which point the temperature uniformity is 0.01 K. (See...) Figure 6 .

[0055] In Comparative Example 1, the blackbody and mounting plate remain unchanged; only the fixing method of the blackbody on the mounting plate is altered. The traditional method is used, placing four polyimide heat-insulating pads with an area equivalent to the four bosses around the blackbody between them and the mounting plate, and securing them with titanium alloy screws. Each of the four heat-insulating pads is a cylindrical pad with an outer diameter of 10mm and an inner diameter of 4.5mm, and the titanium alloy screws have a diameter of 4mm. To achieve the same heat insulation effect, the polyimide pads would need to be approximately 9000mm thick, resulting in a volume far exceeding the dimensions of a typical camera optical path system, making it impossible for the blackbody assembly to enter or exit the optical path.

[0056] In Comparative Example 2, the blackbody and mounting plate remain unchanged, only the fixing method of the blackbody on the mounting plate is changed. The traditional method is still used. The cross-sectional area of ​​the polyimide heat insulation pad and the titanium alloy screw is the same as in Comparative Example 1. The height of the heat insulation pad is adjusted so that the total height of the blackbody and heat insulation pad in Comparative Example 2 is equivalent to the height of the limiting block of this invention, which is 5.5 mm. Because the thickness of the blackbody boss is 3 mm, the thickness of the polyimide heat insulation pad is only 2.5 mm. Therefore, the total thermal resistance of the four heat insulation pads and screws in Comparative Example 2 is approximately 25 °C / W. When the temperature difference is 100 °C, the heat loss reaches 4 W. When the ambient temperature is also 293.15 K, and the blackbody is calibrated to the highest temperature of 345 K, the maximum temperature difference of the blackbody reaches 0.8 K. See [link to relevant documentation]. Figure 7However, at the same calibration temperature of 345K, the maximum temperature of this invention is only 0.09K, a difference of almost an order of magnitude.

[0057] Based on the above analysis, it can be seen that the blackbody component of the present invention has the advantages of good temperature uniformity, light weight, small heat capacity, small size, and fast heating and cooling speed.

[0058] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A multi-stage on-board calibration device for improving calibration speed, characterized in that... Includes a blackbody (1), a controller (10), a temperature control element (2), a temperature sensor (3), a rope (7), a mounting plate (4), a motor (11), and a transmission mechanism (12). The blackbody (1) is suspended and fixed to the mounting plate (4) by a rope (7). The temperature control element (2) and temperature sensor (3) are pasted on the back of the blackbody (1), and the whole body is covered with a multi-layer heat insulation component (13) for radiation heat insulation. The mounting plate (4) is fixedly installed on the transmission mechanism (12), and the motor (11) is used to drive the transmission mechanism (12) to move. When the satellite-borne infrared camera images the target, the motor (11) rotates forward to drive the transmission mechanism (12) to place the blackbody (1) outside the optical path of the satellite-borne infrared camera. When the satellite radiometric calibration is performed, the controller (10) controls the blackbody (1) to the preset temperature through the temperature control element (2) based on the temperature collected by the temperature sensor (3). Then the controller (10) controls the motor to rotate in reverse, drives the transmission mechanism (12) to cut into the optical path with the blackbody (1), and moves out of the optical path after the satellite radiometric calibration is completed. The black body (1) is rectangular, with a boss on each side extending outwards, and a through hole parallel to the side length in the middle of the boss; the mounting plate (4) has 4 fixing seats (5) and a pair of fixing cylinders (6) on its plane, the fixing seats (5) are arc-shaped cylinders with a groove in the middle; the black body (1) is placed on the mounting plate (4), and the 4 fixing seats (5) are located at the 4 corners of the black body; The rope (7) is first wound around the groove of the first fixing seat (5) on the mounting plate, passes through the through hole in the first boss on the black body (1), then wound around the groove of the second fixing seat (5) on the mounting plate, passes through the through hole in the second boss on the black body (1), then wound around the groove of the third fixing seat (5) on the mounting plate, passes through the through hole in the third boss on the black body (1), then wound around the groove of the fourth fixing seat (5) on the mounting plate, passes through the through hole in the fourth boss on the black body (1), and finally, after the two ends of the rope (7) are tightened, they are respectively wrapped around the two fixing cylinders (6) and fixed with glue.

2. A multi-stage on-board calibration device for improving calibration speed according to claim 1, characterized in that... It also includes 4 limiting blocks (8), and 4 limiting seats are provided on the mounting plate. The limiting blocks (8) are installed on the limiting seats of the mounting plate. The 4 limiting blocks (8) are located above the 4 protrusions of the black body (1) and restrict the black body (1) between the limiting blocks (8) and the mounting plate (4).

3. A multi-stage on-board calibration device for improving calibration speed according to claim 2, characterized in that... A flexible gasket (9) is locally placed on the side of the limiting block (8) and the mounting plate (4) facing the blackbody (1).

4. A multi-stage on-board calibration device for improving calibration speed according to claim 3, characterized in that... The limiting block is made of aluminum alloy, and the flexible gasket is made of rubber.

5. A multi-stage on-board calibration device for improving calibration speed according to claim 1, characterized in that: The blackbody (1) is made of copper. The front of the blackbody (1) has a V-shaped groove and the back of the blackbody has a reinforcing rib. The temperature sensor (3) is attached to the reinforcing rib, and the temperature control element avoids the position of the reinforcing rib.

6. A multi-stage on-board calibration device for improving calibration speed according to claim 1, characterized in that: The temperature control element is either a heating element or a cooling element. If the ambient temperature is lower than the preset temperature of the blackbody, a heating element is attached to the back of the blackbody. If the ambient temperature is higher than the preset temperature of the blackbody, a cooling element is attached to the back of the blackbody.

7. A multi-stage on-board calibration device for improving calibration speed according to claim 1, characterized in that: The temperature sensor (3) is a platinum resistance temperature sensor.

8. A multi-stage on-board calibration device for improving calibration speed according to claim 1, characterized in that... The motor (11) is a stepper motor, and the transmission mechanism (12) is a gear transmission mechanism.

9. A multi-stage on-board calibration device for improving calibration speed according to any one of claims 1 to 8, characterized in that: The rope (7) used is a polyimide rope or a glass fiber rope.

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