Calibration equipment and method for calibrating measuring devices

Abstract

A calibration device and a method for calibrating a measuring device are provided that can prevent a decrease in the calibration accuracy of a microwave radiometer. [Solution] The calibration equipment comprises a first stand 11 on which a calibration tool 10 filled with liquid nitrogen is placed, a second stand 12 on which a measuring device 21 to be calibrated is placed, and a fan 13 that blows air to the calibration tool. [Effect] By using a fan to blow air into the calibration fixture, the possibility of condensation occurring in the liquid nitrogen-filled calibration fixture can be reduced, making the calibration results less susceptible to the effects of condensation. This prevents a decrease in the calibration accuracy of the measurement device.

Description

[Technical Field]

[0001] The present disclosure relates to calibration equipment and methods for calibrating measurement devices. [Background technology]

[0002] Conventionally, there are known techniques for calibrating microwave radiometers that observe the amount of water vapor in the atmosphere. For example, see MP-3000A and HATPRO Calibration Comparison, [Retrieved August 27, 2024], Internet, <https: / / radiometrics.com / wp-content / uploads / 2022 / 04 / MP-3000A_and_HATPRO_Calibration_Comparison_160101.pdf> Non-Patent Document 1 discloses a technique for calibrating a microwave radiometer using a container filled with liquid nitrogen. [Prior art documents] [Patent documents]

[0003] [Non-Patent Document 1] MP-3000A and HATPRO Calibration Comparison, [Retrieved August 27, 2024], Internet, <https: / / radiometrics.com / wp-content / uploads / 2022 / 04 / MP-3000A_and_HATPRO_Calibration_Comparison_160101.pdf> Summary of the Invention [Problem to be solved by the invention]

[0004] For example, when a microwave radiometer is calibrated, a container filled with liquid nitrogen is placed around the microwave radiometer. When the microwave radiometer is calibrated in a room temperature environment, condensation may occur on the bottom of the container, which has been cooled by the liquid nitrogen. If the microwave radiometer is calibrated in a state where condensation has occurred, the calibration accuracy may be reduced.

[0005] The present disclosure has been made to solve the above-mentioned problems, and its purpose is to provide a calibration instrument and a calibration method for a measurement device that can prevent a decrease in the calibration accuracy of the measurement device. [Means for solving the problem]

[0006] (1) A calibration device according to an embodiment of the present disclosure includes a first stand on which a calibration tool filled with liquid nitrogen is placed, a second stand on which a measuring device to be calibrated is placed, and a fan that blows air to the calibration tool.

[0007] In this way, by using a fan to blow air into the calibration tool when calibrating a measurement device, the possibility of condensation occurring in the calibration tool filled with liquid nitrogen can be reduced, making the calibration results less susceptible to the effects of condensation, and therefore preventing a decrease in the calibration accuracy of the measurement device.

[0008] (2) In the above (1), the first frame may be provided above the second frame, and the fan may be provided below the first frame.

[0009] If condensation occurs on the bottom surface of the calibration tool, which is the surface facing the measurement device, there is a high possibility that the calibration accuracy of the measurement device will decrease. With the above-described configuration, it is possible to more reliably reduce the possibility of condensation occurring on the bottom surface of the calibration tool.

[0010] (3) In the above (2), the first frame may include an opening, and the fan may send air to the calibration instrument through the opening.

[0011] With this configuration, it is possible to more reliably blow air toward the bottom surface of the calibration tool.

[0012] (4) In the above (2) or (3), when the calibration instrument is placed on the first stand, a flow path may be formed for air to flow from the fan to the outside of the calibration equipment via the space between the calibration instrument and the measurement device.

[0013] With this configuration, the air blown to the bottom surface of the calibration tool can be smoothly discharged to the outside of the calibration tool.

[0014] (5) In any of the above (2) to (4), the airflow direction of the fan may intersect with the vertical direction of the calibration device so that the fan blows air toward the bottom surface of the calibration tool.

[0015] If condensation occurs on the bottom surface of the calibration tool, which is the surface facing the measurement device, there is a high possibility that the calibration accuracy of the measurement device will decrease. With the above-described configuration, it is possible to more reliably reduce the possibility of condensation occurring on the bottom surface of the calibration tool.

[0016] (6) In any of (1) to (5) above, the calibration equipment may be provided with a plurality of the fans, and the fans may be arranged in a row so as to blow air in one direction toward the calibration tool.

[0017] This configuration makes it possible to prevent the air flow generated by one fan from interfering with the air flow generated by another fan, thereby enabling air to be blown to the calibration instrument more efficiently.

[0018] (7) In any of the above (1) to (6), the calibration equipment may further include an alignment unit for aligning the calibration tool with the antenna of the measurement device.

[0019] This configuration makes it easy to align the calibration tool with the antenna of the measurement device.

[0020] (8) In any one of the above (1) to (7), the second stand may be provided at a distance from an installation surface of the calibration equipment.

[0021] With this configuration, the influence of the temperature of the installation surface of the calibration equipment on the measurement device can be reduced, thereby further improving the calibration accuracy of the measurement device.

[0022] (9) In any one of the above (1) to (8), the calibration equipment may further include the calibration tool having a radio wave absorber provided therein.

[0023] For example, a measuring device may measure the brightness temperature of microwaves using the intensity of microwaves radiated from the atmosphere and a reference value of the intensity. This reference value needs to be calibrated, and the above-described configuration makes it possible to more reliably calibrate the reference value using the intensity of microwaves radiated from a radio wave absorber.

[0024] (10) In any one of the above (1) to (9), the second frame may include a guide portion for guiding the measuring device.

[0025] With this configuration, the measuring device can be easily installed on the second stand.

[0026] (11) In any of the above (1) to (10), the calibration device may further include a calibration tool including a display unit that indicates the amount of liquid nitrogen filled.

[0027] With this configuration, the amount of liquid nitrogen filled in the calibration tool can be easily determined.

[0028] (12) In any of (1) to (11) above, the second stand may include a main surface on which the measuring device is installed and an adjustment unit that can adjust the height of the main surface from the installation surface of the calibration equipment depending on the size of the measuring device.

[0029] With this configuration, the height of the main surface of the second stand from the installation surface can be adjusted to an appropriate height depending on the size of the measuring device to be calibrated, thereby reducing the effect of the temperature of the installation surface on the measuring device when calibrating measuring devices of various sizes.

[0030] (13) In any one of the above (1) to (12), wheels may be provided below the second frame.

[0031] This configuration allows the calibration equipment to be easily moved.

[0032] (14) A method for calibrating a measuring device according to an embodiment of the present disclosure includes the steps of preparing calibration equipment including a first stand on which a calibration tool filled with liquid nitrogen is placed, a second stand on which a measuring device to be calibrated is placed, and a fan provided on the first stand, placing the measuring device on the second stand, placing the calibration tool on the first stand, and blowing air toward the calibration tool using the fan.

[0033] In this way, by using a fan to blow air into the calibration tool when calibrating a measuring device, the possibility of condensation occurring in the calibration tool filled with liquid nitrogen can be reduced, making the calibration results less susceptible to the effects of condensation, and therefore preventing a decrease in the calibration accuracy of the measuring device. [Effects of the Invention]

[0034] According to the present disclosure, it is possible to prevent a decrease in the calibration accuracy of a measurement device. [Brief explanation of the drawings]

[0035] [Figure 1] FIG. 1 is a perspective view showing a configuration of a calibration device according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a side view showing the configuration of a calibration device according to an embodiment of the present disclosure. [Figure 3] FIG. 3 is a perspective view showing the configuration of a first frame and a second frame in a calibration device according to an embodiment of the present disclosure. [Figure 4] FIG. 4 is a front view showing the configuration of a calibration device according to an embodiment of the present disclosure. [Figure 5] FIG. 5 is a side view showing the configuration of a calibration device according to an embodiment of the present disclosure. [Figure 6] FIG. 6 is a cross-sectional view showing an example of the configuration of a calibration tool in the calibration device according to the embodiment of the present disclosure. [Figure 7] FIG. 7 is a flowchart defining an example method for calibrating a microwave radiometer using a calibration device according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0036] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, identical or corresponding parts are designated by the same reference numerals, and their description will not be repeated. Furthermore, at least some of the embodiments described below may be combined in any manner.

[0037] [Calibration equipment configuration] Fig. 1 is a perspective view showing a configuration of a calibration device according to an embodiment of the present disclosure. Fig. 2 is a side view showing a configuration of the calibration device according to an embodiment of the present disclosure. With reference to Figs. 1 and 2, calibration device 101 is a device for calibrating a microwave radiometer 21. Microwave radiometer 21 is an example of a measurement device.

[0038] The microwave radiometer 21 measures the amount of water vapor in the atmosphere. Specifically, for example, the microwave radiometer 21 receives microwaves emitted from the atmosphere and measures the brightness temperature of the microwaves based on the intensity of the received microwaves. The microwave radiometer 21 then calculates the amount of water vapor in the atmosphere by substituting the measured brightness temperature into a predetermined arithmetic expression.

[0039] Calibration equipment 101 calibrates the brightness temperature measurement function of microwave radiometer 21. Calibration equipment 101 includes calibration fixture 10, first mount 11, second mount 12, multiple fans 13, multiple support members 14, and multiple stoppers 15. Stoppers 15 are an example of an alignment unit.

[0040] The calibration instrument 10 is filled with liquid nitrogen. The calibration instrument 10 is, for example, a rectangular parallelepiped container. The calibration instrument 10 is made of, for example, polystyrene foam. The calibration instrument 10 may include a display unit that indicates the amount of liquid nitrogen filled.

[0041] The first mount 11 is a mount on which the calibration tool 10 is installed. The second mount 12 is a mount on which the microwave radiometer 21 to be calibrated is installed.

[0042] 1 and 2, the axis along the vertical direction is defined as the z-axis, the axis perpendicular to the z-axis is defined as the x-axis, and the axis perpendicular to the x-axis and z-axis is defined as the y-axis.

[0043] (First mount) 3 is a perspective view showing the configuration of a first frame and a second frame in a calibration device according to an embodiment of the present disclosure. Referring to FIG. 3, first frame 11 is provided above second frame 12. For example, first frame 11 includes a plurality of frame members 31.

[0044] 3, the first frame 11 includes four frame members 31A, 31B, 31C, and 31D that are the plurality of frame members 31. Each frame member 31 is made of a material such as metal.

[0045] For example, the first frame 11 is formed in a rectangular frame shape. Specifically, for example, four frame members 31A, 31B, 31C, and 31D are arranged to form a rectangular frame shape. As a result, the first frame 11 includes an opening P.

[0046] (Support member) Each support member 14 supports the first frame above the second frame 12. In the example shown in Fig. 3, the calibration equipment 101 includes a plurality of support members 14, namely, support members 14A, 14B, 14C, and 14D. Each support member 14 extends in the z-axis direction.

[0047] (Second mount) 2 and 3, for example, the second frame 12 includes a plurality of frame members 51.

[0048] 2 and 3, the second frame 12 includes four frame members 51A, 51B, 51C, and 51D that are the plurality of frame members 51. Each frame member 51 is made of a material such as metal.

[0049] For example, the second frame 12 is formed in a rectangular frame shape. Specifically, for example, four frame members 51A, 51B, 51C, and 51D are arranged to form a rectangular frame shape.

[0050] The second frame 12 includes a main surface Q on which the microwave radiometer 21 is placed. More specifically, for example, the second frame 12 is provided with a top plate 61 on which the microwave radiometer 21 is placed.

[0051] Specifically, in second frame 12, top plate 61 is attached on frame members 51B and 51D. Microwave radiometer 21 is provided on top plate 61. In the present embodiment, the surface of top plate 61 that faces first frame 11 corresponds to main surface Q.

[0052] Second frame 12 also includes frame member 71A provided above frame member 51B and frame member 71B provided above frame member 51D. For example, when microwave radiometer 21 having a small size in the x-axis direction, i.e., the width direction, is installed on second frame 12, top panel 61 is attached to frame members 71A and 71B.

[0053] Referring again to FIG. 2, for example, the second frame 12 is provided at a distance D from the installation surface S of the calibration equipment 101.

[0054] Specifically, for example, in the second frame 12, each frame member 51 is supported by a plurality of support members 14 so that a bottom surface 52 of the frame member 51 is spaced a distance D from the installation surface S.

[0055] In addition, the calibration equipment 101 may be provided with wheels below the second stand 12 to facilitate movement of the calibration equipment 101.

[0056] Furthermore, second frame 12 may include a guide portion for guiding microwave radiometer 21. Specifically, for example, when microwave radiometer 21 is installed on second frame 12, frame members 51B, 51D of second frame 12 may include, as the guide portion, a rail portion for guiding microwave radiometer 21 by sliding it in the y-axis direction.

[0057] (fan) 4 is a front view showing the configuration of a calibration instrument according to an embodiment of the present disclosure. With reference to FIGS. 1, 2, and 4, each fan 13 blows air toward calibration instrument 10. For example, each fan 13 is provided below first frame 11.

[0058] In this embodiment, for example, each fan 13 is provided on the bottom surface of a frame member 31C of the first frame 11. Note that each fan 13 may also be provided below and to the side of the first frame 11.

[0059] For example, the fans 13 are arranged in a line in the x-axis direction so as to blow air in one direction toward the calibration fixture 10.

[0060] Here, calibration tool 10 is installed on top of frame members 31A, 31B, 31C, and 31D of first frame 11 so as to close opening P. Bottom surface 10a of calibration tool 10 is exposed from opening P.

[0061] The liquid nitrogen is filled into the calibration tool 10 while the calibration tool 10 is installed on the first frame 11. This allows the calibration work of the microwave radiometer 21 to be performed more safely than a method in which the calibration tool 10 is filled with liquid nitrogen and then the calibration tool 10 is placed above the microwave radiometer 21.

[0062] 5 is a side view showing the configuration of a calibration instrument according to an embodiment of the present disclosure. With reference to FIGS. 2 and 5, when the calibration instrument 10 is placed on the first frame 11, a flow path C is formed through which air flows from the fans 13 to the outside of the calibration instrument 101 via the space V between the calibration instrument 10 and the microwave radiometer 21. Each fan 13 blows air to the bottom surface 10a of the calibration instrument 10 through an opening P in the first frame 11.

[0063] For example, the airflow direction of each fan 13 intersects with the vertical direction of the calibration equipment 101, that is, the z-axis direction, so that the fan 13 blows air toward the bottom surface 10a of the calibration fixture 10.

[0064] Specifically, for example, each fan 13 is fixed at an angle with respect to the bottom surface of the frame member 31C so that the air blowing surface 13a of the fan 13 faces the bottom surface 10a of the calibration instrument 10.

[0065] In the present embodiment, the multiple fans 13 in the calibration equipment 101 are arranged in a row on the bottom surface of the frame member 31C, but this is not limitative. At least one of the multiple fans 13 may be provided on the bottom surface of a frame member 31 other than the frame member 31C, instead of on the bottom surface of the frame member 31C. Furthermore, at least one of the fans 13 may be provided on the second frame 12 or the support member 14, rather than on the first frame 11.

[0066] Furthermore, the second frame 12 may include an adjustment unit that can adjust the height of the main surface Q from the installation surface S of the calibration device 101 in accordance with the size of the microwave radiometer 21. Specifically, for example, the second frame 12 may include, as the adjustment unit, rails that allow the frame members 51B, 51D, on which the top plate 61 is provided, to slide in the z-axis direction.

[0067] (Stopper) 3 to 5, stopper 15 is a member for aligning calibration tool 10 with the antenna of microwave radiometer 21. Stopper 15 is made of a material such as metal.

[0068] In this embodiment, for example, calibration equipment 101 includes a plurality of stoppers 15, that is, stoppers 15a, 15b, 15c, and 15d.

[0069] Stoppers 15a and 15b are stoppers 15 for aligning the calibration tool 10 with the antenna of microwave radiometer 21 in the z-axis direction. Stoppers 15a and 15b are provided on frame member 31B, for example.

[0070] Stoppers 15c and 15d are stoppers 15 for aligning the calibration tool 10 with the antenna of microwave radiometer 21 in the y-axis direction. Stoppers 15c and 15d are provided on frame member 31C, for example.

[0071] (Radio wave absorber) 6 is a cross-sectional view showing an example of the configuration of a calibration tool in the calibration equipment according to the embodiment of the present disclosure. Referring to Fig. 6, for example, a radio wave absorber 41 is provided inside calibration tool 10.

[0072] Radio wave absorber 41 emits microwaves for calibrating microwave radiometer 21. The material of radio wave absorber 41 is, for example, a dielectric material. When calibration tool 10 is filled with liquid nitrogen, radio wave absorber 41 is immersed in the liquid nitrogen.

[0073] Here, the microwave radiometer 21 shown in FIG. 1 measures the brightness temperature of the microwave based on the intensity of the microwave in the atmosphere and a reference intensity Rs calculated in advance.

[0074] For example, the microwave radiometer 21 calculates the reference intensity Rs based on the intensity of the microwave radiated from the radio wave absorber 41. Specifically, for example, the microwave radiometer 21 calculates the reference intensity Rs based on the intensity R1 of the microwave radiated from the radio wave absorber 41 having an absolute temperature of 77 K and the intensity R2 of the microwave radiated from the radio wave absorber 41 having an absolute temperature of 300 K, i.e., from the radio wave absorber 41 in a room temperature environment.

[0075] Microwave radiometer 21 calibrates reference intensity Rs using calibration device 101 shown in Fig. 1. Specifically, when calibration tool 10 is filled with liquid nitrogen, microwave radiometer 21 receives microwaves radiated from radio wave absorber 41 and measures intensity R1 of the microwaves. When calibration tool 10 is not filled with liquid nitrogen, microwave radiometer 21 receives microwaves radiated from radio wave absorber 41 and measures intensity R2 of the microwaves. Then, microwave radiometer 21 calibrates reference intensity Rs based on the measured intensities R1 and R2.

[0076] [Operation flow] FIG. 7 is a flowchart defining an example method for calibrating a microwave radiometer using a calibration device according to an embodiment of the present disclosure.

[0077] Referring to FIG. 7, first, a user of calibration equipment 101 prepares calibration equipment 101 (step ST101).

[0078] Next, the user installs the microwave radiometer 21 on the second stand 12 of the calibration equipment 101 (step ST102).

[0079] Next, the user places the calibration tool 10 on the first stand 11 of the calibration equipment 101, and fills the calibration tool 10 with liquid nitrogen (step ST103).

[0080] Next, the user causes the fan 13 of the calibration equipment 101 to blow air toward the calibration instrument 10 (step ST104).

[0081] Next, the user calibrates the microwave radiometer 21 while the fan 13 is blowing air toward the calibration tool 10 (step ST105).

[0082] In the embodiment of the present disclosure, the calibration target of the calibration device 101 is the microwave radiometer 21, but this is not limited to this. The calibration target may also be a measurement device that measures other types of electromagnetic waves than microwaves, specifically, a measurement device that measures radio waves, light, radio waves, X-rays, etc. other than microwaves. Furthermore, the calibration target is not limited to a measurement device that measures electromagnetic waves, but may be any measurement device that measures physical phenomena, chemical phenomena, biological phenomena, etc.

[0083] The above-described embodiments should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0084] 10 Calibration equipment 11 First Mount 12 Second Mount 13 Fan 13a Blowout surface 14 Support member 15 Stopper 21 Microwave Radiometer 31,51 Frame members 41 Radio wave absorber 101 Calibration equipment P opening Q Main surface S Installation surface

Claims

1. a first stand on which a calibration tool filled with liquid nitrogen is placed; a second stand on which a measuring device to be calibrated is placed; and a fan for blowing air into the calibration fixture.

2. the first frame is provided above the second frame, 2. The calibration equipment according to claim 1, wherein the fan is provided below the first stand.

3. the first mount includes an opening; The calibration equipment of claim 2 , wherein the fan blows air through the opening to the calibration fixture.

4. 4. The calibration instrument according to claim 2, wherein when the calibration instrument is placed on the first stand, a flow path is formed for air to flow from the fan to the outside of the calibration instrument via a space between the calibration instrument and the measurement device.

5. 4. The calibration instrument according to claim 2, wherein the airflow direction of the fan intersects with the up-down direction of the calibration instrument so that the fan blows air toward a bottom surface of the calibration fixture.

6. the calibration equipment comprises a plurality of the fans; 3. The calibration equipment according to claim 1, wherein the plurality of fans are arranged in a line so as to blow air in one direction toward the calibration fixture.

7. The calibration device further comprises:

3. The calibration equipment according to claim 1, further comprising an alignment unit for aligning the calibration tool with an antenna of the measurement device.

8. 3. The calibration equipment according to claim 1, wherein the second stand is provided at a distance from an installation surface of the calibration equipment.

9. The calibration device further comprises:

3. The calibration equipment according to claim 1, further comprising the calibration tool having a radio wave absorber disposed therein.

10. 3. The calibration equipment according to claim 1, wherein the second stand includes a guide portion for guiding the measurement device.

11. The calibration device further comprises:

3. The calibration device according to claim 1, further comprising a display unit that displays the amount of liquid nitrogen filled.

12. The second frame is a main surface on which the measurement device is placed; 3. The calibration instrument according to claim 1, further comprising an adjustment unit that adjusts the height of the main surface from an installation surface of the calibration instrument in accordance with the size of the measurement device.

13. 3. The calibration equipment according to claim 1, wherein wheels are provided below the second stand.

14. preparing a calibration device including a first stand on which a calibration tool filled with liquid nitrogen is placed, a second stand on which a measurement device to be calibrated is placed, and a fan provided on the first stand; placing the measurement device on the second stand; placing the calibration tool on the first mount; and blowing air toward the calibration fixture with the fan.

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