Manufacturing method for observation device, observation device, and computer program

Abstract

This manufacturing method is for manufacturing an observation device (110) for observing precipitation particles such as raindrops. The manufacturing method comprises: a step for preparing an antenna module (30) that transmits electromagnetic waves (E) and receives electromagnetic waves (E) reflected by a storage container (20) and electromagnetic waves (E) reflected by precipitation particles; a step for outputting information relating to a placement position for placing the antenna module (30) in the storage container (20) on the basis of the value of the dielectric constant of the wall (21) of the storage container (20), the value of the thickness of the wall (21), and a theoretical formula for converting a function indicating the relationship between the electromagnetic waves (E) transmitted from the antenna module (30) and the electromagnetic waves (E) reflected by the storage container (20) into a function having, as variables, the dielectric constant of the wall (21), the thickness of the wall (21), and the placement position; and a step for storing the antenna module (30) in the storage container (20) and placing the antenna module (30) at the placement position.

Description

Method for manufacturing an observation device, observation device, and computer program

[0001] This invention relates to a method for manufacturing an observation device, an observation device, and a computer program.

[0002] Non-Patent Document 1 discloses a small Doppler rain sensor. The small Doppler rain sensor in Non-Patent Document 1 comprises a Doppler module and a rectangular transparent acrylic case, with the Doppler module housed inside the transparent acrylic case. Non-Patent Document 1 discloses fixing the directional direction of the Doppler module to vertically upward.

[0003] Shiho Onomura, Kazuki Minami, and Nobuhito Nakayoshi, "An Attempt at Rainfall Movement Observation Using a Small Doppler Rainfall Sensor," Transactions of the Japan Society of Civil Engineers, Series B1 (Hydraulic Engineering), 2020, Vol. 76, No. 2, I_211-I_216.

[0004] However, Non-Patent Document 1 does not disclose the position of the Doppler module within the transparent acrylic case. The inventors of this case have diligently researched observation devices for observing precipitation particles. As a result, they have found that the position of the antenna module within the housing container that contains the antenna module affects the accuracy of precipitation particle observation.

[0005] The present invention has been made in view of the above problems, and its purpose is to provide a method for manufacturing an observation device, an observation device, and a computer program that can observe precipitation particles with greater accuracy.

[0006] A method for manufacturing an observation device according to the present invention is a method for manufacturing an observation device that observes precipitation particles using transmitted electromagnetic waves and electromagnetic waves reflected by precipitation particles, and includes the steps of: preparing a containment container; preparing an antenna module that transmits electromagnetic waves and receives the electromagnetic waves reflected by the containment container and the electromagnetic waves reflected by precipitation particles; a theoretical formula that converts a function showing the relationship between the electromagnetic waves transmitted from the antenna module and the electromagnetic waves reflected by the containment container into a function having the dielectric constant of the wall portion of the containment container, the thickness of the wall portion, and the installation position in which the antenna module is installed within the containment container as variables; outputting information regarding the installation position based on the value of the dielectric constant of the wall portion and the value of the thickness of the wall portion; preparing a holding member for holding the antenna module; and housing the antenna module and the holding member in the containment container and installing the antenna module at the installation position.

[0007] In one embodiment, the method for manufacturing the observation device further includes the step of electrically connecting the antenna module and the recording device, wherein the antenna module outputs a voltage based on the electromagnetic waves emitted from the antenna module and the electromagnetic waves received by the antenna module, and the recording device records the voltage output from the antenna module.

[0008] In one embodiment, the portion of the outer surface of the wall of the containment container through which the electromagnetic waves pass is convex.

[0009] In one embodiment, the theoretical formula includes Maxwell's equations for the electromagnetic waves emitted from the antenna module, Maxwell's equations for the electromagnetic waves reflected at the boundary between the inner surface of the wall of the containment container and the internal space of the containment container, Maxwell's equations for the electromagnetic waves incident on the wall of the containment container, Maxwell's equations for the electromagnetic waves reflected at the boundary between the outer surface of the wall of the containment container and the external space of the containment container, and Maxwell's equations for the electromagnetic waves transmitted from the wall of the containment container to the external space.

[0010] The observation device according to the present invention is an observation device for observing precipitation particles using transmitted electromagnetic waves and electromagnetic waves reflected by precipitation particles, comprising: a housing container having a wall portion that partitions an internal space and an external space; an antenna module that transmits electromagnetic waves and receives the electromagnetic waves reflected by the housing container and the electromagnetic waves reflected by the precipitation particles; and a holding member that holds the antenna module, wherein the housing container houses the holding member that holds the antenna module in the internal space, the antenna module is installed at an installation position within the housing container determined based on a predetermined theoretical formula, the dielectric constant value of the wall portion and the thickness value of the wall portion, and the predetermined theoretical formula converts a function showing the relationship between the electromagnetic waves transmitted from the antenna module and the electromagnetic waves reflected by the housing container into a function having the dielectric constant of the wall portion, the thickness of the wall portion and the installation position as variables.

[0011] In one embodiment, the observation device further comprises a recording device electrically connected to the antenna module, wherein the antenna module outputs a voltage based on the electromagnetic waves emitted from the antenna module and the electromagnetic waves received by the antenna module, and the recording device records the voltage output from the antenna module.

[0012] In one embodiment, the portion of the outer surface of the wall of the containment container through which the electromagnetic waves pass is convex.

[0013] In one embodiment, the antenna module installed at the installation location transmits electromagnetic waves mainly in a vertically upward direction.

[0014] In one embodiment, the theoretical formula includes Maxwell's equations for the electromagnetic waves emitted from the antenna module, Maxwell's equations for the electromagnetic waves reflected at the boundary between the inner surface of the wall of the containment container and the internal space, Maxwell's equations for the electromagnetic waves incident on the wall of the containment container, Maxwell's equations for the electromagnetic waves reflected at the boundary between the outer surface of the wall of the containment container and the external space, and Maxwell's equations for the electromagnetic waves transmitted from the wall of the containment container to the external space.

[0015] The present invention relates to a computer program that causes a computer to function to output information regarding the installation position of an antenna module in an observation device that observes precipitation particles using transmitted electromagnetic waves and electromagnetic waves reflected by precipitation particles, wherein the observation device comprises the antenna module, a holding member for holding the antenna module, and a housing container having a wall portion that partitions an internal space and an external space, the internal space housing the holding member for holding the antenna module, and the antenna module emits electromagnetic waves, and the electromagnetic waves reflected by the housing container and the precipitation The system receives the electromagnetic waves reflected by water particles, and the installation position indicates the position in the containment container where the antenna module is installed. The computer program, upon receiving the dielectric constant value of the wall and the thickness value of the wall, causes the computer to output information regarding the installation position based on a predetermined theoretical formula, the dielectric constant value of the wall, and the thickness value of the wall. The predetermined theoretical formula converts a function showing the relationship between the electromagnetic waves emitted from the antenna module and the electromagnetic waves reflected by the containment container into a function having the dielectric constant of the wall, the thickness of the wall, and the installation position as variables.

[0016] According to the method for manufacturing the observation device, the observation device, and the computer program of the present invention, it becomes possible to observe precipitation particles with greater accuracy.

[0017] This figure shows an observation system including an observation device according to an embodiment of the present invention. This is a cross-sectional view of a first holding member included in the observation device according to an embodiment of the present invention. This is a cross-sectional view of a second holding member included in the observation device according to an embodiment of the present invention. This is a plan view of an antenna module included in the observation device according to an embodiment of the present invention. This figure shows an example of the output voltage of an antenna module included in the observation device according to an embodiment of the present invention. This is a cross-sectional view showing a part of the observation device according to an embodiment of the present invention. This is an enlarged cross-sectional view showing a part of the observation device according to an embodiment of the present invention. This figure shows the relationship between the theoretical value of the output voltage of the antenna module and the installation position of the antenna module. This is a process diagram showing a method for manufacturing the observation device according to an embodiment of the present invention. This is a block diagram of an information processing device that executes an installation position determination program according to an embodiment of the present invention. This is a flowchart showing the processing flow by the installation position determination support program according to an embodiment of the present invention. This figure shows the results of a first experiment according to an embodiment of the present invention and the theoretical value of the AC component. This figure shows the results of a second experiment according to an embodiment of the present invention. This figure shows an example of the results of a second experiment according to an embodiment of the present invention. This figure shows an example of the results of an actual measurement taken by installing the observation device according to an embodiment of the present invention outdoors. This figure shows an enlarged view of a part of the graph in Figure 15. This figure shows another example of the results of an actual measurement taken by installing the observation device according to an embodiment of the present invention outdoors. This figure shows an enlarged view of a part of the graph in Figure 17. This figure shows yet another example of the results of an actual measurement taken by installing the observation device according to an embodiment of the present invention outdoors. This figure shows an enlarged view of a part of the graph in Figure 19. This figure shows the relationship between the hourly cumulative value calculated based on actual measurements taken by installing an observation device according to an embodiment of the present invention outdoors, and the hourly rainfall measured separately.

[0018] Hereinafter, embodiments of the present invention will be described with reference to Figures 1 to 11, and examples of the present invention will be described with reference to Figures 12 to 21. However, the present invention is not limited to the following embodiments and examples, and can be implemented in various forms without departing from its essence. In addition, explanations may be omitted where necessary to avoid repetition. Furthermore, in the figures, the same or corresponding parts are denoted by the same reference numerals and their descriptions are not repeated.

[0019] Figure 1 shows an observation system 100 including the observation device 110 of this embodiment. The observation device 110 is installed outdoors, for example. Figure 1 shows the observation device 110 installed outdoors. The observation device 110 observes precipitation particles using transmitted electromagnetic waves E and electromagnetic waves E reflected by precipitation particles. Note that "transmitted electromagnetic waves E" may be "generated electromagnetic waves E" or "radiated electromagnetic waves E". In this embodiment, the observation device 110 observes raindrops RD. Raindrops RD are an example of "precipitation particles". In the following, this embodiment and this embodiment will be described using raindrops RD as an example. However, the observation device 110 may be installed indoors. For example, the observation device 110 may be installed indoors to observe raindrops RD (water droplets) of artificial rain. Note that precipitation particles are not limited to raindrops RD and water droplets; precipitation particles include snow, sleet, etc., in addition to raindrops RD and water droplets.

[0020] In this embodiment, the observation system 100 calculates precipitation from the observation results of raindrop RD by the observation device 110. Specifically, as shown in Figure 1, the observation system 100 comprises an observation device 110 and an analysis device 80. The observation device 110 comprises a first holding member 10, a housing container 20, an antenna module 30, a second holding member 40, a support member 50, a cable 60, and a recording device 70. Figure 1 shows cross-sections of the first holding member 10, the housing container 20, the antenna module 30, the second holding member 40, and the support member 50. The vertical direction in Figure 1 indicates the orientation of the observation device 110 when in use. In the following, to facilitate understanding, this embodiment and this embodiment will be described based on the orientation of the observation device 110 when in use.

[0021] The first holding member 10 holds the antenna module 30. The first holding member 10 is an example of a "holding member". Specifically, the first holding member 10 fixes and holds the antenna module 30 within the housing container 20 so that the antenna surface 30a of the antenna module 30 faces upward and is horizontal. The antenna module 30 is installed in a predetermined installation position within the housing container 20 by the first holding member 10. Here, the installation position indicates the position in the housing container 20 where the antenna module 30 is installed.

[0022] A gap (space) is formed between the antenna module 30, which is installed in a predetermined position, and the housing container 20. The first holding member 10 holds the antenna module 30 so that the gap between the antenna module 30 and the housing container 20 is formed above the antenna module 30 (antenna surface 30a).

[0023] The antenna module 30 and the first retaining member 10 are housed in the internal space of the housing container 20. More specifically, the housing container 20 houses the first retaining member 10 that holds the antenna module 30 such that the antenna surface 30a of the antenna module 30 faces upward and is horizontal. The housing container 20 also houses the first retaining member 10 such that an inner space 22 is formed between the first retaining member 10 and the housing container 20. The gap between the antenna module 30 and the housing container 20 is part of the inner space 22. The inner space 22 is formed above the first retaining member 10. The housing container 20 may be, for example, a capsule having an upper member and a lower member, with the upper member and lower member being separable. In this case, for example, the upper member and lower member may be separated, the first retaining member 10 that holds the antenna module 30 may be held inside the lower member, and then the upper edge of the lower member and the lower edge of the upper member may be fitted together to house the antenna module 30 and the first retaining member 10 in the housing container 20.

[0024] In this embodiment, the containment container 20 is spherical. Because the containment container 20 is spherical, raindrops RD can be observed regardless of the direction from which they fall on the containment container 20. The material of the containment container 20 is not particularly limited as long as it is a material that can transmit electromagnetic waves E. The containment container 20 may be made of a resin such as polystyrene, for example.

[0025] The second holding member 40 holds the housing container 20. More specifically, the second holding member 40 holds the housing container 20 that houses the antenna module 30 and the first holding member 10 so that the antenna surface 30a of the antenna module 30 faces upward and is horizontal. In this embodiment, the second holding member 40 is a "base". Hereafter, the second holding member 40 may be referred to as "base 40". Also, the first holding member 10 may be referred to as "holding member 10".

[0026] The support member 50 supports the base 40. More specifically, the support member 50 holds the base 40 so that the antenna surface 30a of the antenna module 30 faces upward and is horizontal.

[0027] The support member 50 may be, for example, a support column. In this case, one end of the support column (support member 50) is fixed to the base 40, and the support column (support member 50) extends vertically downward from the base 40. The other end of the support column (support member 50) is fixed to, for example, a concrete block. The concrete block is, for example, placed on the ground.

[0028] The antenna module 30 emits electromagnetic waves E from its antenna surface 30a. The antenna module 30 also receives electromagnetic waves E reflected by the housing 20 and electromagnetic waves E reflected by raindrops RD (precipitation particles) on its antenna surface 30a.

[0029] In this embodiment, the antenna module 30 outputs a voltage based on the electromagnetic wave E emitted from the antenna surface 30a of the antenna module 30 and the electromagnetic wave E received by the antenna surface 30a of the antenna module 30. Specifically, the antenna module 30 outputs a voltage obtained by multiplying the electromagnetic wave E emitted from the antenna surface 30a and the electromagnetic wave E received by the antenna surface 30a. In the following description, the voltage output from the antenna module 30 may be referred to as the "output voltage". Also, the value of the voltage output from the antenna module 30 may be referred to as the "output voltage value".

[0030] The antenna module 30 continuously emits electromagnetic waves E. In other words, electromagnetic waves E are continuous waves. When the antenna module 30 is installed in a predetermined position, it emits electromagnetic waves E toward the inner space 22. Specifically, the antenna module 30 mainly emits electromagnetic waves E in the vertically upward direction.

[0031] A portion of the electromagnetic wave E is reflected by the housing container 20. As will be explained in detail with reference to Figure 7, a portion of the electromagnetic wave E is reflected at the boundary between the inner surface 21a of the wall portion 21 of the housing container 20 and the inner space 22 of the housing container 20 (the internal space of the housing container 20). Another portion of the electromagnetic wave E is reflected at the boundary between the outer surface 21b of the wall portion 21 of the housing container 20 and the external space of the housing container 20. The remainder of the electromagnetic wave E passes through the housing container 20. A portion of the electromagnetic wave E that has passed through the housing container 20 is reflected by raindrops RD during rainy weather. Therefore, the antenna module 30 receives the electromagnetic wave E reflected by the housing container 20 during sunny weather, and receives the electromagnetic wave E reflected by the housing container 20 and the electromagnetic wave E reflected by raindrops RD during rainy weather. As a result, the output voltage value of the antenna module 30 fluctuates depending on whether or not the antenna module 30 receives the electromagnetic wave E reflected by raindrops RD. Furthermore, the antenna module 30 is incident on both electromagnetic waves E reflected by the inner surface 21a of the wall portion 21 of the housing container 20 and electromagnetic waves E reflected by the outer surface 21b of the wall portion 21 of the housing container 20. Because multiple reflected waves thus incident on the antenna module 30 from the housing container 20, the installation position of the antenna module 30 within the housing container 20 affects the sensitivity of the antenna module 30.

[0032] The output voltage of the antenna module 30 fluctuates significantly when raindrops RD come into contact with the housing 20. In this embodiment, the antenna module 30 mainly emits electromagnetic waves E vertically upward from its center CP (see Figure 4). Therefore, when raindrops RD come into contact with the portion 20a of the housing 20 that faces the center of the antenna module 30, the output voltage of the antenna module 30 fluctuates significantly. Hereinafter, the portion 20a of the housing 20 that faces the center of the antenna module 30 may be referred to as the "zenith portion 20a". The zenith portion 20a is located vertically above the center of the antenna module 30.

[0033] The recording device 70 is electrically connected to the antenna module 30. Specifically, a cable 60 electrically connects the antenna module 30 and the recording device 70. The cable 60 transmits the output voltage of the antenna module 30 to the recording device 70. The recording device 70 records the output voltage value of the antenna module 30. The sampling rate of the recording device 70 is, for example, 10 kHz. According to this embodiment, by electrically connecting the antenna module 30 and the recording device 70, the output voltage value of the antenna module 30 can be recorded at the site where raindrop RD is observed.

[0034] The analysis device 80 calculates the amount of precipitation by analyzing the output voltage value of the antenna module 30 recorded in the recording device 70. The analysis device 80 may be, for example, a general-purpose computer equipped with a processor and memory. The analysis device 80 may be installed in a location different from the site where raindrops (precipitation particles) are observed. For example, the analysis device 80 may be installed indoors.

[0035] More specifically, the analysis device 80 calculates precipitation by statistically processing the output voltage value of the antenna module 30. Specifically, the analysis device 80 extracts the component that fluctuates due to rainfall from the output voltage value of the antenna module 30. Hereinafter, the component of the output voltage value of the antenna module 30 that fluctuates due to rainfall may be referred to as the "voltage fluctuation component." The analysis device 80 calculates an integrated value by integrating the voltage fluctuation components extracted from the output voltage value of the antenna module 30. Then, the analysis device 80 calculates precipitation based on the integrated value.

[0036] For example, the analysis device 80 calculates the moving average value per unit time of the output voltage value of the antenna module 30. Then, the analysis device 80 calculates the absolute value of the deviation from the moving average value of the output voltage value of the antenna module 30. The unit time is, for example, one second. The calculated absolute value of the deviation represents the voltage fluctuation component. The analysis device 80 further integrates the voltage fluctuation component (absolute value of the deviation) at regular intervals. Then, the analysis device 80 calculates the amount of precipitation for a regular period based on the integrated value of the voltage fluctuation component for that regular period. The regular period is, for example, one hour. In this case, the analysis device 80 calculates the amount of precipitation every hour.

[0037] Figure 2 is a cross-sectional view of the first holding member 10 included in the observation device 110 of this embodiment. As shown in Figure 2, the holding member 10 has a recess 11 and a through hole 12. Note that in Figure 2, for the sake of explanation, the vertical direction is shown as in Figure 1.

[0038] The recess 11 holds the antenna module 30 shown in Figure 1. Specifically, the holding member 10 has a spherical shape with the upper part cut off. The recess 11 is formed on the upper surface 10a of the holding member 10 and recesses downward from the upper surface 10a. The shape of the recess 11 substantially matches the outer shape of the antenna module 30. For example, the recess 11 may be rectangular in plan view. By housing the antenna module 30 in the recess 11, the antenna module 30 is held by the holding member 10 (see Figure 1).

[0039] The through-hole 12 extends from the inner surface of the recess 11 to the outer surface 10b of the retaining member 10. One end 12a of the through-hole 12 opens onto the outer surface 10b of the retaining member 10. The outer surface 10b refers to the portion of the surface of the retaining member 10 excluding the top surface 10a. The outer surface 10b is spherical. More specifically, the outer surface 10b refers to a part of a sphere. The other end 12b of the through-hole 12 may open, for example, onto the bottom surface 11a of the recess 11.

[0040] A cable 60, as shown in Figure 1, is inserted into the through-hole 12. For example, a cable 60 connected to an antenna module 30 is inserted into the through-hole 12 from the other end 12b, and a portion of the cable 60 is led out from one end 12a of the through-hole 12 to the outside of the holding member 10 (see Figure 1).

[0041] The holding member 10 is formed so that the antenna module 30 held by the holding member 10 is installed in a predetermined position within the housing container 20. In the example shown in Figure 2, the holding member 10 is formed so that the antenna module 30 housed in the recess 11 is installed in a predetermined position within the housing container 20. The material of the holding member 10 is not particularly limited. For example, the holding member 10 may be made of resin.

[0042] In this embodiment, the retaining member 10 has a spherical shape with the upper part cut off, but the shape of the retaining member 10 is not particularly limited as long as the antenna module 30 can be installed in a predetermined installation position within the housing container 20. For example, the retaining member 10 may consist of a flat plate-shaped member with a recess 11 formed therein and a support column that supports the flat plate-shaped member. Also, in this embodiment, the antenna module 30 is housed in the recess 11, but the configuration for positioning the antenna module 30 is not limited to the recess 11. For example, the antenna module 30 may be positioned by fastening members such as screws or by adhesive.

[0043] Figure 3 is a cross-sectional view of the second holding member 40 (base 40) included in the observation device 110 of this embodiment. As shown in Figure 3, the base 40 is substantially rectangular parallelepiped in shape. The base 40 has a recess 41 and a through hole 42. The material of the base 40 is not particularly limited. For example, the base 40 may be made of resin. Note that in Figure 3, the vertical direction is shown as in Figure 1 for the sake of explanation.

[0044] The recess 41 holds the storage container 20 shown in Figure 1. Specifically, the recess 41 is formed on the upper surface 40a of the base 40 and recesses downward from the upper surface 40a. In this embodiment, the shape of the recess 41 is a part of a sphere, and a part of the storage container 20 is housed in the recess 41 (see Figure 1). By housing the storage container 20 in the recess 41, the storage container 20 is held by the base 40.

[0045] The through-hole 42 extends from the inner surface 41a of the recess 41 to the side surface 40b of the base 40. One end 42a of the through-hole 42 opens onto the side surface 40b of the base 40. The other end 42b of the through-hole 42 opens onto the inner surface 41a of the recess 41. The cable 60 shown in Figure 1 is inserted into the through-hole 42. Specifically, the cable 60, which is led out from the through-hole 12 of the holding member 10 shown in Figure 2, is inserted into the through-hole 42 from the other end 42b through a through-hole 21 that penetrates the wall portion 21 of the housing container 20, and the tip of the cable 60 is led out from one end 42a of the through-hole 42 to the outside of the base 40 (see Figure 1).

[0046] Figure 4 is a plan view of the antenna module 30 included in the observation device 110 of this embodiment. As shown in Figure 4, one or more antennas 31 are formed on the antenna surface 30a. Note that in Figure 4, the front-to-back direction and the left-to-right direction are shown for the convenience of explanation. However, the front-to-back direction and left-to-right direction shown in Figure 4 are not intended to limit the orientation of the observation device during manufacturing and use according to the present invention.

[0047] In this embodiment, the antenna module 30 is a rectangular flat plate. For example, the width of the antenna module 30 in the left-right direction is 25 mm. The width of the antenna module 30 in the front-back direction is 25 mm. The thickness of the antenna module 30 is 7 mm. The electromagnetic wave E emitted from the antenna module 30 is, for example, a 24 GHz band microwave. The electromagnetic wave E is mainly emitted from the center CP of the antenna module 30. For example, the 3 dB beam width of the antenna module 30 in the left-right direction is 80°. The 3 dB beam width of the antenna module 30 in the front-back direction is 35°. The antenna module 30 is, for example, a patch antenna.

[0048] Figure 5 shows an example of the output voltage of the antenna module 30 included in the observation device 110 of this embodiment. More specifically, Figure 5 shows the fluctuation in the output voltage value of the antenna module 30 caused by the contact of a raindrop RD with respect to the zenith 20a of the containment container 20, as described with reference to Figure 1. In Figure 5, the first graph G1 shows the output voltage of the antenna module 30 installed at a predetermined installation position inside the containment container 20. The vertical axis represents the voltage value. The horizontal axis represents time. Time t1 indicates the time when the raindrop RD contacted the zenith 20a of the containment container 20.

[0049] As shown in Figure 5, the output voltage value of the antenna module 30 is a first voltage base value V1 until time t1 is reached. The first voltage base value V1 is approximately constant, and the output voltage value of the antenna module 30 is maintained at approximately constant value until time t1 is reached. In other words, the output voltage value of the antenna module 30 remains in a steady state until the raindrop RD contacts the top 20a of the containment container 20.

[0050] When a raindrop RD contacts the zenith 20a of the containment container 20 (time t1), the output voltage value of the antenna module 30 fluctuates significantly. Specifically, the output voltage value of the antenna module 30 rises sharply from a first voltage base value V1 to a voltage value V2, and then gradually decreases from a voltage value V2 to a second voltage base value V3. The amount of fluctuation from the first voltage base value V1 to a voltage value V2 is, for example, 100 mV or more. By installing the antenna module 30 at a predetermined installation position inside the containment container 20 in this way, the voltage fluctuation (amount of voltage fluctuation) caused by the detection of a raindrop RD can be made larger. As a result, it becomes possible to observe raindrops RD (precipitation particles) with greater accuracy.

[0051] After the raindrop RD contacts the top 20a of the containment container 20, the output voltage value of the antenna module 30 is maintained at the second voltage base value V3. The second voltage base value V3 is approximately constant. Therefore, the output voltage value of the antenna module 30 decreases from the voltage value V2 to the second voltage base value V3, and then remains at an approximately constant value. In other words, the output voltage value of the antenna module 30 decreases sharply from the voltage value V2 to the second voltage base value V3, and then reaches a steady state.

[0052] In the example shown in Figure 5, the second voltage base value V3 is greater than the first voltage base value V1. This is because a portion of the raindrop RD adheres to and remains on the top 20a of the containment container 20. In other words, the antenna module 30 receives electromagnetic waves E reflected by the raindrop RD adhering to the top 20a of the containment container 20, causing the second voltage base value V3 to be greater than the first voltage base value V1. Specifically, when a raindrop RD collides with the top 20a of the containment container 20, some of the raindrop RD scatters into the surroundings, some of the raindrop RD flows down from the top 20a along the containment container 20, and the rest of the raindrop RD remains on the containment container 20.

[0053] Next, a method for determining the installation position of the antenna module 30 will be explained with reference to Figures 6 to 8. Figure 6 is a cross-sectional view showing a part of the observation device 110 of this embodiment. Note that in Figure 6, the vertical direction is shown as in Figure 1 for the sake of explanation.

[0054] As shown in Figure 6, the containment container 20 has a wall portion 21. In this embodiment, the wall portion 21 is spherical, as described with reference to Figure 1. The wall portion 21 separates the internal space from the external space of the containment container 20. The wall portion 21 has an inner surface 21a and an outer surface 21b. The wall portion 21 also has a thickness d. In this embodiment, the thickness d of the wall portion 21 is uniform.

[0055] The antenna module 30 is installed at a distance h from the wall portion 21. As a result, the antenna module 30 is installed in a predetermined position. Specifically, the holding member 10 that holds the antenna module 30 is housed in the housing container 20 such that the center CP of the horizontally positioned antenna module 30 is located vertically below at a distance h from the portion of the inner surface 21a of the wall portion 21 that faces the center CP of the antenna module 30.

[0056] In this embodiment, distance h indicates the installation position of the antenna module 30. Distance h is determined based on a predetermined theoretical formula, the dielectric constant ε of the wall portion 21 of the housing container 20, and the thickness d of the wall portion 21 of the housing container 20. The predetermined theoretical formula is an equation that converts a function showing the relationship between electromagnetic waves E emitted from the antenna module 30 and electromagnetic waves E reflected by the housing container 20 into a function having the dielectric constant ε of the wall portion 21 of the housing container 20, the thickness d of the wall portion 21 of the housing container 20, and distance h (installation position) as variables.

[0057] Figure 7 is an enlarged cross-sectional view showing a part of the observation device 110 of this embodiment. More specifically, Figure 7 schematically shows an enlarged view of a part of the housing container 20, the antenna module 30, and a part of the holding member 10. Also, Figure 7 shows the electromagnetic wave E. More specifically, Figure 7 shows the electric field E. Ａ（＋） , E Ａ（－） , E Ｂ（＋） , E Ｂ（－） and E Ｃ This is shown. Note that in Figure 7, for the sake of explanation, the vertical direction is shown as in Figure 1.

[0058] In this embodiment, the vertical direction (the z-axis direction) is defined as the Z-axis direction, and the point where the Z-axis passing through the zenith of the housing container 20 intersects the inner surface 21a of the housing container 20 is defined as the origin. Then, the coordinate of the Z-axis is determined as the distance h. Also, the direction of the electric field orthogonal to the Z-axis is defined as the X-axis direction, and the direction of the magnetic field orthogonal to the Z-axis is defined as the Y-axis direction. Note that the zenith of the housing container 20 is included in the outer surface 21b of the housing container 20. That is, the position of the zenith of the housing container 20 is a position separated from the origin by the thickness d of the wall portion 21 in the +Z side. In the following description, the coordinate of the Z-axis may be described as "z". The coordinate z of the Z-axis of the origin is "z = 0". The coordinate z of the Z-axis of the zenith is "z = d".

[0059] Also, here, the region from the antenna surface 30a of the antenna module 30 to the inner surface 21a of the housing container 20 is defined as region A, the inside of the wall portion 21 of the housing container 20 is defined as region B, and the external space of the housing container 20 is defined as region C. The electromagnetic wave E transmits or reflects at the boundary (z = 0) between region A and region B, and transmits or reflects at the boundary (z = d) between region B and region C. Note that region A is the inner space 22 described with reference to FIG. 1.

[0060] As shown in FIG. 7, an electric field E Ａ（＋） is transmitted from the antenna module 30. The Maxwell equation of the electric field E Ａ（＋） transmitting through region A is expressed by the following equation (1).

[0061] The Maxwell equation of the electric field E Ａ（－） reflected at the boundary (z = 0) between region A and region B is expressed by the following equation (2). In other words, equation (2) shows the Maxwell equation of the electric field E Ａ（－） reflected at the boundary (z = 0) between the inner surface 21a of the wall portion 21 of the housing container 20 and the inner space 22 (the internal space of the housing container 20) of the housing container 20.

[0062] The Maxwell equation of the electric field E Ｂ（＋） transmitting through region B is expressed by the following equation (3). In other words, equation (3) shows the Maxwell equation of the electric field E Ｂ（＋） incident on the wall portion 21 of the housing container 20.

[0063] The electric field E reflected at the boundary between region B and region C (z = d) Ｂ（－） Maxwell's equations are expressed by the following equation (4). In other words, equation (4) represents the electric field E reflected at the boundary (z=d) between the outer surface 21b of the wall portion 21 of the containment container 20 and the space outside the containment container 20. Ｂ（－） We will now present Maxwell's equations.

[0064] Electric field E passing through region C Ｃ Maxwell's equations are expressed by the following equation (5). In other words, equation (5) represents the electric field E transmitted from the wall 21 of the containment container 20 to the outside space. Ｃ We will now present Maxwell's equations.

[0065] More specifically, equations (1) to (5) are one-dimensional approximations of Maxwell's equations. In this embodiment, the distance h can be determined from the directivity of the antenna module 30 using the vertical one-dimensional Maxwell's equations. However, the distance h may also be determined using Maxwell's equations that are not one-dimensionally approximated (three-dimensional equations).

[0066] In equations (1) to (5), e ｘ ω represents the unit vector in the X-axis direction, and ω represents the frequency. Also, z represents the coordinate of the Z-axis, and k ０ k indicates the wavenumber. ０ It is defined by the following equation (6). In equation (6), f ０ This indicates the frequency of the electromagnetic wave E emitted from the antenna module 30. In this embodiment, the electromagnetic wave E is a microwave, for example, f ０ is "24.15 GHz". Also, c is the speed of light in a vacuum (3.0 × 10⁻⁶). ８ ms -１ ) indicates k ０ = 2πf ０ / c...(6)

[0067] Furthermore, in equations (1) to (5), A ０ is electric field E Ａ（＋） The complex amplitude of R is shown, ０ is electric field E Ａ（－） The complex amplitude of A is shown.１ is electric field E Ｂ（＋） The complex amplitude of R is shown, １ is electric field E Ｂ（－） The complex amplitude of A is shown. ２ is electric field E Ｃ This shows the complex amplitude. In equations (3) and (4), n represents the complex refractive index of the wall portion 21 with respect to electromagnetic waves E (microwaves). The complex refractive index n is equal to the relative permittivity ε / ε ０ It is obtained from the square root of ε. Here, ε ０ The permeability of vacuum is (8.85 × 10⁻⁶). －１２ Fm －１ This shows that ε represents the dielectric constant of the wall portion 21, as already explained. More specifically, ε represents the dielectric constant of the wall portion 21 with respect to electromagnetic waves E (microwaves).

[0068] From equations (1) to (5), the electric fields E in regions A, B, and C are given. Ａ , E Ｂ and E Ｃ These are expressed by equations (7) to (9) below.

[0069] Therefore, according to Faraday's law, the magnetic field B in regions A, B, and C is Ａ , B Ｂ and B Ｃ These are expressed by the following equations (10) to (12).

[0070] From the continuity of the electric and magnetic fields at the boundary between region A and region B (z=0), the above complex amplitude A can be obtained from equations (7), (8), (10), and (11). ０ , R ０ A １ and R １ The following equations (13) and (14) hold true for A. ０ +R ０ = A １ +R １ ... (13) A ０ -R ０ = n(A １ -R １ ) ... (14)

[0071] Furthermore, from the continuity of the electric and magnetic fields at the boundary between region B and region C (z=d), the above complex amplitude A can be obtained from equations (8), (9), (11), and (12). １ , R １ and A ２ The following equations (15) and (16) hold true for this.

[0072] Then, by solving the system of equations (13) to (16) above, we obtain equations (17) and (18) below.

[0073] Below, the electric field E Ａ（＋） "The transmitting electric field E" Ａ（＋） It states, " and electric field E Ａ（－） "Received electric field E" Ａ（－） It may be written as "."

[0074] As already explained, the antenna module 30 outputs a voltage obtained by multiplying the electromagnetic wave E emitted from the antenna surface 30a by the electromagnetic wave E received by the antenna surface 30a. Therefore, the emitted electric field E Ａ（＋） and the received electric field E Ａ（－） The voltage obtained by multiplying by the DC component is the output electric field E. Ａ（＋） and the received electric field E Ａ（－） It is proportional to the inner product of the two. In other words, the emitting electric field E Ａ（＋） and the received electric field E Ａ（－） The AC component of the voltage obtained by multiplying by is the generating electric field E Ａ（＋） and the received electric field E Ａ（－） It is proportional to the dot product of . Therefore, the following equation (19) holds.

[0075] Equation (19) is an example of a predetermined theoretical formula. Equation (19) is given by the generating electric field E Ａ（＋） and the received electric field E Ａ（－） The function showing the relationship (left side) is transformed into a function (right side) that has the dielectric constant ε of the wall portion 21, the thickness d of the wall portion 21, and the coordinate z of the Z axis as variables.

[0076] Here, the generating electric field E Ａ（＋）and the received electric field E Ａ（－） The function showing the relationship is the generating electric field E, as shown on the left side of equation (19). Ａ（＋） and the received electric field E Ａ（－） This is the formula for the dot product of the two. Also, equation (19) has the coordinate z of the Z axis as a variable. Furthermore, the complex amplitude A ０ And the complex amplitude R ０ The formula for the product of the complex conjugate includes equations (17) and (18), where equation (18) has the complex refractive index n of the wall portion 21 with respect to electromagnetic waves E (microwaves) and the thickness d of the wall portion 21 as variables. The complex refractive index n has the dielectric constant ε of the wall portion 21 as a variable.

[0077] Therefore, the right-hand side of equation (19) has the dielectric constant ε of the wall portion 21, the thickness d of the wall portion 21, and the coordinate z of the Z-axis as variables. Thus, equation (19) can be calculated with the coordinate z of the Z-axis as a variable, based on the value of the dielectric constant ε of the wall portion 21, the value of the thickness d of the wall portion 21, and equations (17) to (19). Note that equation (19) is derived using equations (1) to (18). Therefore, equation (19) includes equations (1) to (5).

[0078] Specifically, based on the dielectric constant ε of the wall portion 21, the complex refractive index n of the wall portion 21 (relative permittivity ε / ε) is determined. ０ The value of the square root of is calculated, and the value of the thickness d of the wall portion 21 and the value of the complex refractive index n are substituted into equation (18) to calculate the value of "α", and the value of the complex refractive index n and the value of "α" are substituted into equation (17) to obtain the complex amplitude A ０ And the complex amplitude R ０ The product of the complex conjugate of can be found. Therefore, equation (19) can be calculated with the coordinate z of the Z axis as the variable. And, as is clear from equation (19), the emitting electric field E Ａ（＋） and the received electric field E Ａ（－） The inner product with the originating electric field E Ａ（＋） When the amplitude is unit, it is proportional to the trigonometric function.

[0079] Note that the generating electric field E Ａ（＋） and the received electric field E Ａ（－） The voltage obtained by multiplying by corresponds to the steady-state voltage explained with reference to Figure 5. That is, the emitting electric field E Ａ（＋） and the received electric field E Ａ（－）The value of the voltage obtained by multiplying [the above] is corresponding to the voltage base value described with reference to FIG. 5. Hereinafter, the transmission electric field E Ａ（＋） and the received electric field E Ａ（－） The voltage obtained by multiplying may be described as the "steady-state voltage".

[0080] FIG. 8 is a diagram showing the relationship between the theoretical value of the output voltage of the antenna module 30 and the installation position (distance h) of the antenna module 30. Specifically, FIG. 8 shows the theoretical value (relative value) of the AC component of the steady-state voltage output from the antenna module 30 when the transmission electric field E Ａ（＋） has a unit amplitude.

[0081] Hereinafter, the steady-state voltage output from the antenna module 30 when the transmission electric field E Ａ（＋） has a unit amplitude may be described as the "steady-state output voltage". Also, the theoretical value of the AC component of the steady-state output voltage may be described as the "theoretical value of the AC component". Also, the value obtained by adding the DC component to the theoretical value of the AC component may be described as the "theoretical value of the output voltage". Here, the DC component indicates the DC component of the steady-state voltage. The DC component may be estimated from the measured value. The theoretical value (relative value) of the output voltage corresponds to the voltage base value described with reference to FIG. 5.

[0082] In FIG. 8, the second graph G2 shows the AC component (theoretical value) of the steady-state output voltage. More specifically, the second graph G2 shows the AC component of the output voltage of the antenna module 30 calculated based on a predetermined theoretical formula, the value of the dielectric constant ε of the wall portion 21, and the value of the thickness d of the wall portion 21. The vertical axis indicates the theoretical value (relative value) of the AC component. The horizontal axis indicates the distance h. In the present embodiment, the predetermined theoretical formula is the above formula (19). Specifically, the predetermined theoretical formula includes the above formulas (17) to (19).

[0083] As shown in FIG. 8, the AC component of the steady-state output voltage is proportional to a trigonometric function when the transmission electric field E Ａ（＋） has a unit amplitude. Therefore, the steady-state output voltage is proportional to a trigonometric function.

[0084] In this embodiment, the operator determines the distance h (coordinate on the Z axis) by referring to the second graph G2. Therefore, in this embodiment, the installation position of the antenna module 30 is determined based on predetermined theoretical formulas (equations (17) to (19)), the dielectric constant ε of the wall portion 21, and the thickness d of the wall portion 21.

[0085] For example, suppose the recording device 70 is designed not to record voltage values ​​below 0V included in the fluctuation component (voltage fluctuation component) of the output voltage of the antenna module 30. In this case, the operator determines the installation position of the antenna module 30 at a distance h such that the steady-state output voltage is greater than the local minimum of the trigonometric function by a predetermined value. Here, the predetermined value is a value smaller than the local maximum and the value near the local maximum of the trigonometric function, and represents a value such that the theoretical value of the output voltage (voltage base value) is greater than 0V. Specifically, the operator determines the distance h such that the theoretical value of the output voltage (voltage base value) is slightly greater than 0V. For example, the operator may determine the distance h such that the theoretical value of the output voltage (voltage base value) is 25mV greater than 0V.

[0086] In more detail, if the distance h corresponding to the maximum value and the value near the maximum value of the trigonometric function is used as the installation position for the antenna module 30, when a raindrop RD comes into contact with the top 20a of the containment container 20, the output voltage value of the antenna module 30 may fluctuate in the negative direction, and a negative value may be included in the fluctuation component (voltage fluctuation component) of the output voltage of the antenna module 30. Therefore, the output voltage value of the antenna module 30 may not be accurately recorded in the recording device 70. Also, if the distance h corresponding to the minimum value and the value near the minimum value of the trigonometric function is used as the installation position for the antenna module 30, the voltage base value may become 0V or less. Therefore, the output voltage value of the antenna module 30 may not be accurately recorded in the recording device 70. For these reasons, the distance h corresponding to the maximum value and the value near the maximum value of the trigonometric function, and the distance h corresponding to the minimum value and the value near the minimum value of the trigonometric function are excluded from the candidates for the installation position of the antenna module 30.

[0087] Furthermore, the closer the theoretical value of the AC component is to the maximum value or a value near the maximum value of the trigonometric function, the smaller the amount of change in the output voltage value of the antenna module 30 (voltage fluctuation) when the raindrop RD comes into contact with the zenith 20a of the containment container 20. Therefore, the operator determines the distance h such that the theoretical value of the output voltage (voltage base value) is slightly greater than 0V. As a result, the amount of change in the output voltage value of the antenna module 30 when the raindrop RD comes into contact with the zenith 20a of the containment container 20 can be made large enough for observing the raindrop RD. Thus, it becomes possible to observe raindrop RD (precipitation particles) with greater accuracy.

[0088] Next, the manufacturing method of the observation device 110 of this embodiment will be described with reference to Figures 1 to 9. Figure 9 is a process diagram showing the manufacturing method of the observation device 110 of this embodiment. As shown in Figure 9, the manufacturing method of the observation device 110 of this embodiment includes steps S1 to S5.

[0089] In step S1, the antenna module 30 and the housing container 20, as described with reference to Figures 1 and 4, are prepared.

[0090] In step S2, as explained with reference to Figures 6 to 8, the installation position of the antenna module 30 is determined based on predetermined theoretical formulas (formulas (17) to (19)), the value of the thickness d of the wall portion 21 of the housing container 20, and the value of the dielectric constant ε of the wall portion 21 of the housing container 20. For details, as will be described later with reference to Figures 10 and 11, information regarding the installation position of the antenna module 30 is output by a computer program. Then, the worker determines the distance h (installation position) based on the information regarding the installation position.

[0091] In step S3, the holding member 10, which was described with reference to Figures 1 and 2, is prepared. More specifically, the holding member 10 is prepared to install the antenna module 30 at the installation position determined in step S2.

[0092] Step S4 is an assembly step. In step S4, as shown in Figure 1, the antenna module 30 is held by the holding member 10, and the holding member 10 that holds the antenna module 30 is housed in the housing container 20. As a result, the antenna module 30 is installed at the installation position within the housing container 20 determined in step S2. After that, as shown in Figure 1, the housing container 20 is held by the base 40. The base 40, which has been described with reference to Figures 1 and 3, only needs to be prepared before step S4.

[0093] In step S5, as shown in Figure 1, the antenna module 30 and the recording device 70 are electrically connected via the cable 60.

[0094] The manufacturing method of the observation device 110 of this embodiment has been described above with reference to Figures 1 to 9. According to the manufacturing method of the observation device 110 of this embodiment, the installation position of the antenna module 30 is determined as described with reference to Figures 6 to 8. Therefore, by using the observation device 110 manufactured by the manufacturing method of this embodiment, it becomes possible to observe raindrop RD (precipitation particles) with greater accuracy.

[0095] Next, the computer program of this embodiment will be described with reference to Figures 10 and 11. Figure 10 is a block diagram of the information processing device 200 that executes the installation location determination support program of this embodiment.

[0096] As shown in Figure 10, the information processing device 200 includes an input unit 201, an output unit 202, a storage unit 203, and a processing unit 204.

[0097] The input unit 201 is a user interface device or man-machine interface device operated by an operator. The input unit 201 inputs signals corresponding to the operator's operation to the processing unit 204. The input unit 201 may have, for example, a keyboard and a mouse. Alternatively, the input unit 201 may have a touch sensor. The touch sensor inputs signals indicating touch operations by the operator to the processing unit 204. The touch sensor may be superimposed on the display surface of a display device. In this case, a graphical user interface may be configured by the touch sensor and the display device.

[0098] In this embodiment, the operator operates the input unit 201 to input the value of the thickness d of the wall portion 21 of the housing container 20 and the value of the dielectric constant ε. Furthermore, the operator operates the input unit 201 to input a range of distance h. The range of distance h may be arbitrarily determined by the operator based on the dimensions of the housing container 20. For example, the range of distance h may indicate the range in which the antenna module 30 can be physically installed inside the housing container 20.

[0099] The output unit 202 is controlled by the processing unit 204 and outputs information regarding the installation position of the antenna module 30. The output unit 202 may include a display device such as a liquid crystal display device or an organic EL (Electro-Luminescence) display device. Alternatively, the output unit 202 may include an image forming device such as a printer or a multifunction device.

[0100] In this embodiment, the output unit 202 outputs the theoretical values ​​of the AC components as described with reference to Figures 6 to 8. For example, the output unit 202 may output the second graph G2 as described with reference to Figure 8. Specifically, if the output unit 202 includes a display device, the display device displays the theoretical values ​​of the AC components (e.g., the second graph G2). Also, if the output unit 202 includes an image forming apparatus, the image forming apparatus prints an image of the theoretical values ​​of the AC components (e.g., the second graph G2) onto a recording medium. In this embodiment, the theoretical values ​​of the AC components are an example of "information regarding the installation position of the antenna module 30".

[0101] The storage unit 203 has a storage device. Specifically, the storage unit 203 has a main memory. The main memory includes, for example, a semiconductor memory. The storage unit 203 may further have an auxiliary storage device. The auxiliary storage device includes, for example, at least one of a semiconductor memory and a hard disk drive. The storage unit 203 may also include removable media.

[0102] The storage unit 203 stores computer programs and setting information. The storage unit 203 is controlled by the processing unit 204 and stores the value of the thickness d and dielectric constant ε of the wall portion 21 of the containment container 20, as well as the range of distance h, which are input via the input unit 201. The storage unit 203 also stores the installation location determination support program 205. The installation location determination support program 205 is a computer program.

[0103] The processing unit 204 executes computer programs stored in the memory unit 203 to perform various processes such as numerical calculations, information processing, and device control. For example, the processing unit 204 may have at least one of a general-purpose processor, a dedicated processor, and an integrated circuit.

[0104] Specifically, the processing unit 204 executes the installation location determination support program 205 stored in the storage unit 203, thereby causing the output unit 202 to output information regarding the installation location of the antenna module 30.

[0105] Figure 11 is a flowchart showing the processing flow by the installation position determination support program 205 of this embodiment. The processing shown in Figure 11 is executed by the processing unit 204, which was described with reference to Figure 10. The processing shown in Figure 11 includes step S11 and step S12.

[0106] In step S11, the processing unit 204 obtains the value of the thickness d and the dielectric constant ε of the wall portion 21 of the containment container 20, which are input by the operator. In this embodiment, the processing unit 204 further obtains the range of the distance h, which is input by the operator.

[0107] When the processing unit 204 receives the value of the thickness d of the wall portion 21 of the housing container 20, the value of the dielectric constant ε, and the range of distance h as input, it causes the output unit 202 to output information regarding the installation position of the antenna module 30 based on the value of the thickness d of the wall portion 21 of the housing container 20, the value of the dielectric constant ε, predetermined theoretical formulas (formulas (17) to (19)), and the range of distance h (step S12).

[0108] More specifically, the processing unit 204 outputs the theoretical value of the AC component to the output unit 202 as information regarding the installation position, based on the value of the thickness d and dielectric constant ε of the wall portion 21 of the containment container 20, predetermined theoretical values ​​(equations (17) to (19)), and the range of distance h, as explained with reference to Figures 6 to 8. For example, the processing unit 204 may output the second graph G2, explained with reference to Figure 8, to the output unit 202 as the theoretical value of the AC component. As a result, the operator can determine the distance h by referring to the theoretical value of the AC component output by the output unit 202, as explained with reference to Figure 8.

[0109] The installation location determination support program 205 of this embodiment has been described above with reference to Figures 10 and 11. According to the installation location determination support program 205 of this embodiment, the theoretical value of the AC component can be output from the output unit 202. Therefore, the operator can determine the installation location of the antenna module 30 as described with reference to Figures 6 to 8. Thus, according to this embodiment, it is possible to observe raindrops RD (precipitation particles) with greater accuracy.

[0110] In this embodiment, the processing unit 204 caused the output unit 202 to output the theoretical value of the AC component. However, the processing unit 204 may instead output the theoretical value of the output voltage (the value obtained by adding the DC component to the theoretical value of the AC component) to the output unit 202.

[0111] As described above with reference to Figures 1 to 11, this embodiment makes it possible to observe raindrop RD (precipitation particles) with greater accuracy. Furthermore, this embodiment provides a small and portable observation device 110. Moreover, the observation device 110 of this embodiment can be manufactured at low cost.

[0112] For example, the measurement accuracy of a typical tipping bucket rain gauge is limited by the size of the tipping bucket, making it difficult to measure the amount of rainfall from very light rain. Furthermore, tipping bucket rain gauges may not adequately capture raindrops during strong winds. In addition, tipping bucket rain gauges require regular maintenance because branches and leaves can clog the tipping bucket, or malfunctions can occur in the internal moving parts. Moreover, tipping bucket rain gauges are difficult to install in hard-to-reach locations such as mountainous areas.

[0113] In contrast, this embodiment allows for the measurement of even minute rainfall compared to a tipping bucket rain gauge. Furthermore, because the containment container 20 is spherical, rainfall can be measured even in strong winds. Moreover, because the containment container 20 of this embodiment is spherical, branches and leaves are less likely to accumulate on the surface of the containment container 20, and because there are no moving parts, the frequency of maintenance can be reduced compared to a tipping bucket rain gauge. In addition, because the observation device 110 of this embodiment is small and portable, it is easier to install in hard-to-reach places such as mountainous areas compared to a tipping bucket rain gauge.

[0114] Furthermore, according to this embodiment, since the electromagnetic waves E are mainly emitted vertically upward, the antenna module 30 can receive the electromagnetic waves E reflected by raindrops RD that have come into contact with the zenith portion 20a of the containment container 20. Therefore, compared to a configuration in which the electromagnetic waves E are emitted horizontally, the amount of fluctuation (voltage fluctuation component) of the output voltage value of the antenna module 30 can be increased. Thus, it becomes possible to observe raindrops RD (precipitation particles) with greater accuracy.

[0115] Furthermore, according to this embodiment, the installation position of the antenna module 30 is determined using a theoretical formula derived from Maxwell's equations. Therefore, the installation position that maximizes the fluctuation amount (voltage fluctuation component) of the output voltage value of the antenna module 30 can be determined with greater accuracy.

[0116] Embodiments of the present invention have been described above with reference to the drawings (Figures 1 to 11). However, the present invention is not limited to the embodiments described above, and can be implemented in various forms without departing from its essence. Furthermore, the multiple components disclosed in the above embodiments can be modified as appropriate. For example, some components from all the components shown in one embodiment may be added to the components of another embodiment, or some components from all the components shown in one embodiment may be deleted from the embodiment.

[0117] The drawings schematically show each component in order to facilitate understanding of the invention, and the thickness, length, number, spacing, etc. of each component shown may differ from the actual dimensions due to the convenience of drawing creation. Furthermore, the configuration of each component shown in the above embodiments is merely an example and is not particularly limiting, and it goes without saying that various modifications are possible without substantially departing from the effects of the present invention.

[0118] For example, in the embodiment described with reference to Figures 1 to 11, the containment container 20 is spherical, but the shape of the containment container 20 is not limited to a spherical shape. It is sufficient that the portion of the outer surface 21b of the wall portion 21 of the containment container 20 that transmits electromagnetic waves E is a convex curved surface. Because the portion of the outer surface 21b of the wall portion 21 of the containment container 20 that transmits electromagnetic waves E is a convex curved surface, it becomes possible to observe raindrops RD regardless of the direction from which they fall on the containment container 20.

[0119] Furthermore, in the embodiments described with reference to Figures 1 to 11, the electromagnetic wave E was a continuous wave, but the antenna module 30 may also emit the electromagnetic wave E intermittently.

[0120] Furthermore, in the embodiment described with reference to Figures 1 to 11, the thickness d of the wall portion 21 of the containment container 20 was uniform, but the thickness of the wall portion 21 does not have to be uniform. In this case, the value of the thickness d of the portion of the wall portion 21 of the containment container 20 through which the electromagnetic wave E passes is substituted into "d" in the above-described equation (18).

[0121] Furthermore, in the embodiment described with reference to Figures 1 to 11, the recording device 70 was specified not to record voltage values ​​of 0V or less included in the fluctuation component (voltage fluctuation component) of the output voltage of the antenna module 30. However, the recording device 70 may record voltage values ​​of 0V or less included in the fluctuation component (voltage fluctuation component) of the output voltage of the antenna module 30.

[0122] Furthermore, in the embodiments described with reference to Figures 1 to 11, the observation device 110 recorded the voltage output from the antenna module 30, but the physical quantities recorded are not limited to voltage, as long as precipitation particles can be observed. For example, the current or power output from the antenna module 30 may be recorded.

[0123] Furthermore, in the embodiments described with reference to Figures 1 to 11, the precipitation particles were raindrops RD, but the precipitation particles observed by the observation device 110 are not limited to raindrops RD. The observation device 110 may also observe precipitation particles other than raindrops RD, such as snow or sleet.

[0124] Furthermore, in the embodiment described with reference to Figures 1 to 11, the operator operated the input unit 201 to input data such as the thickness d of the wall portion 21 to the processing unit 204. However, the configuration for inputting data such as the thickness d of the wall portion 21 to the processing unit 204 is not limited to this. For example, a communication interface device may be provided in the information processing device 200, and data such as the thickness d of the wall portion 21 may be obtained from a network.

[0125] Furthermore, in the embodiment described with reference to Figures 1 to 11, the storage container 20 and the second holding member 40 (base) were different components, but the storage container 20 and the second holding member 40 (base) may be a single component. For example, the lower member of the storage container 20 and the second holding member 40 (base) may be formed integrally.

[0126] The present invention will be described in more detail below using examples. However, the present invention is not limited in any way to the scope of the examples.

[0127] In this embodiment, a commercially available patch antenna (IPM-165 from Innoseent GmbH) was used for the antenna module 30. The antenna module 30 was flat. The width of the antenna module 30 in the left-right direction (see FIG. 4) was 25 mm. The width of the antenna module 30 in the front-back direction was 25 mm (see FIG. 4). The thickness of the antenna module 30 was 7 mm. The electromagnetic wave E emitted from the antenna module 30 was a microwave. The frequency f ０ of the electromagnetic wave E (microwave) was 24.15 GHz. The 3 dB beam width of the antenna module 30 in the left-right direction (see FIG. 4) was 80°. The 3 dB beam width of the antenna module 30 in the front-back direction (see FIG. 4) was 35°.

[0128] In this embodiment, a commercially available transparent capsule was used for the storage container 20. The transparent capsule was spherical with a diameter of 6 cm. The transparent capsule was made of polystyrene. The thickness d of the wall portion 21 of the transparent capsule was 1.45 mm. Also, the holding member 10 and the pedestal 40 were fabricated by a 3D printer. A single-pipe was used for the support member 50. As described with reference to FIG. 1, one end of the single-pipe was fixed to the pedestal 40, and the other end of the single-pipe was fixed to the concrete block.

[0129] In this embodiment, a recording device 70 was fabricated. The sampling rate of the recording device 70 was 10 kHz. Also, the recording device 70 used in this embodiment was specified not to record a voltage value of 0 V or less when the fluctuation component (voltage fluctuation component) of the output voltage of the antenna module 30 included a voltage value of 0 V or less.

[0130] In this embodiment, as described with reference to FIGS. 6 to 8, the theoretical value of the AC component was obtained. Specifically, the relative permittivity of polystyrene with respect to a 1 GHz microwave is 2.53, and the dielectric loss tangent is 36×10 ４ Therefore, the relative permittivity ε / ε ０ of polystyrene (the wall portion 21 of the storage container 20) was "2.53 - 0.009i". Thus, the complex refractive index n of polystyrene (the wall portion 21 of the storage container 20) became the value shown in the following formula (20).

[0131] Therefore, the thickness d (d = 1.45 mm) of the wall portion 21 of the transparent capsule (container 20), the complex refractive index n of the polystyrene (container 20), and the frequency f of the electromagnetic wave E (microwave) ０ (f ０ (=24.15 GHz) and the speed of light in a vacuum c (c = 3.0 × 10⁻¹⁵ GHz) ８ ms -１ ) and, according to the above equations (6) and (17) to (19), the complex amplitude A ０ And the complex amplitude R ０ The value of the product of with its complex conjugate is shown in equation (21) below.

[0132] Figure 12 shows the results of the first experiment according to this embodiment and the theoretical value of the AC component. In Figure 12, the vertical axis on the left shows the theoretical value (relative value) of the AC component, and the horizontal axis shows the distance h. The third graph G3 shows the AC component (theoretical value) of the steady-state output voltage. Specifically, the third graph G3 is calculated using the above equations (6), (17) to (21) and the frequency f of the electromagnetic wave E (microwave). ０ (f ０ (=24.15 GHz) and the speed of light in a vacuum c (c = 3.0 × 10⁻¹⁵ GHz) ８ ms -１ It was calculated using ).

[0133] In Figure 12, the "×" indicates the results of the first experiment. Specifically, the "×" indicates the steady-state output voltage (experimental result). The vertical axis on the right shows the voltage value relative to the results of the first experiment. The first experiment was conducted indoors.

[0134] In the first experiment, the steady-state output voltage value was recorded by varying the distance h, as explained with reference to Figures 6 and 7. In other words, in the first experiment, the voltage base value was recorded by varying the distance h, as explained with reference to Figure 5.

[0135] Specifically, the steady-state output voltage value (measured value) was recorded for each distance h, varying from 8.55 mm, 11.05 mm, 12.55 mm, 13.55 mm, 14.55 mm, 16.05 mm, 18.55 mm, 21.05 mm, and 23.55 mm. Note that Figure 12 does not show the experimental results when the distance h is 21.05 mm or when the distance h is 23.55 mm.

[0136] As shown in Figure 12, the theoretical value of the AC component was proportional to a trigonometric function, as explained with reference to Figures 6 to 8. Furthermore, the results of the first experiment were in general agreement with the theoretical value of the AC component, except for the DC component.

[0137] In this embodiment, a second experiment was conducted along with the first experiment. Figure 13 shows the results of the second experiment according to this embodiment. In the second experiment, the amount of variation in the output voltage of the antenna module 30 was measured at distances H of 10 mm, 12.5 mm, 14 mm, 15 mm, 16 mm, 17.5 mm, 20 mm, 22.5 mm, and 25 mm. Distance H is the distance obtained by adding the thickness d (1.45 mm) of the wall portion 21 of the transparent capsule (container 20) to the distance h explained with reference to Figures 6 and 7. In other words, distance H represents the distance from the zenith as explained with reference to Figure 7.

[0138] Specifically, in the second experiment, water droplets were dropped from a position vertically above the containment container 20 (zenith) using a syringe pump. The syringe pump was fixed at a position 1.3 m vertically above the containment container 20 (zenith). Hereafter, the amount of fluctuation in the output voltage of the antenna module 30 may be referred to as "voltage fluctuation." The second experiment was conducted indoors.

[0139] In Figure 13, the vertical axis represents the voltage value, and the horizontal axis represents the distance H (H = h + 1.45). Also in Figure 13, the black circles represent the voltage base value, that is, the output voltage of the antenna module 30 before water droplets are dispensed by the syringe pump. The arrows indicate the voltage fluctuation.

[0140] As shown in Figure 13, when the distance H was 12.5 mm, 14 mm, and 20 mm, the voltage base value was 0 V or less, so the voltage fluctuation could not be recorded. Also, when the antenna module 30 was installed at distances H (H = 10 mm, 17.5 mm, and 25 mm) corresponding to the maximum value and vicinity of the maximum value in the third graph G3 of Figure 12, the output voltage of the antenna module 30 fluctuated in the negative direction. Furthermore, the voltage fluctuation became smaller as the distance H approached the maximum value in the third graph G3 of Figure 12.

[0141] Figure 14 shows an example of the results of the second experiment according to this embodiment. In Figure 14, the fourth graph G4 shows the output voltage of the antenna module 30 measured when the distance H is 15 mm. The vertical axis represents the voltage value, and the horizontal axis represents time. Time t1 indicates the time when the droplet was dropped using the syringe pump.

[0142] As shown in Figures 13 and 14, when the distance H was 15 mm, the voltage base value was slightly greater than 0 V. Furthermore, when droplets were dropped using a syringe pump, the output voltage of the antenna module 30 fluctuated in the positive direction, with the voltage fluctuation amount exceeding 100 mV. Specifically, when the distance H was 15 mm, the voltage base value was approximately 25 mV, and when water droplets were dropped, the output voltage value became approximately 130 mV. Therefore, in this embodiment, the antenna module 30 was installed at a position where the distance H was 15 mm. The reason why the voltage base value after dropping water droplets is greater than the voltage base value before dropping water droplets is explained with reference to Figure 5, so the explanation is omitted here.

[0143] Figure 15 shows an example of the results obtained by installing the observation device 110 according to this embodiment outdoors and taking measurements. In Figure 15, the vertical axis represents the voltage value and the horizontal axis represents the time. Furthermore, the fifth graph G5 shows the measurement results. Specifically, the fifth graph G5 shows the output voltage of the antenna module 30 during the time period (22:00 to 23:00) when an hourly precipitation of 9.5 mm was observed at the Sapporo Regional Meteorological Observatory. As shown in Figure 15, the observation device 110 of this embodiment measured a large voltage fluctuation during the 60 minutes when precipitation occurred.

[0144] Figure 16 is an enlarged view of a portion of the graph (fifth graph G5) in Figure 15. More specifically, Figure 16 shows an enlarged view of the output voltage of the antenna module 30 recorded between 22:52 and 22:54. In Figure 16, the vertical axis represents the voltage value, and the horizontal axis represents the time.

[0145] As shown in Figure 16, the observation device 110 of this embodiment confirmed that voltage spikes due to raindrop RD were occurring in the output voltage of the antenna module 30. Furthermore, as explained with reference to Figure 1, the amount of precipitation was calculated by statistically processing the voltage fluctuation component. A correlation was found between the calculated amount of precipitation and the hourly precipitation observed at the Sapporo Regional Meteorological Observatory. Prior to the statistical processing, the output voltage of the antenna module 30 was subjected to filtering, as described later, with reference to Figures 19 and 20.

[0146] Figure 17 shows another example of the results obtained by installing the observation device 110 according to this embodiment outdoors and taking measurements. In Figure 17, the vertical axis represents the voltage value and the horizontal axis represents the time. Graph 6 G6 shows the measurement results. Specifically, Graph 6 G6 shows the output voltage of the antenna module 30 during the period (2:30 to 3:30) when rainfall was detected at the Sapporo Regional Meteorological Observatory but no hourly precipitation was observed. In other words, Graph 6 G6 shows the output voltage of the antenna module 30 during the period of light rainfall with an hourly precipitation of 0 mm. As shown in Figure 17, the observation device 110 of this embodiment measured a gradual voltage fluctuation during the 60 minutes when precipitation occurred.

[0147] Figure 18 is an enlarged view of a portion of the graph (Graph G6, Section 6) in Figure 17. More specifically, Figure 18 shows an enlarged view of the output voltage of the antenna module 30 recorded between 3:00 and 3:02. In Figure 18, the vertical axis represents the voltage value, and the horizontal axis represents the time.

[0148] As shown in Figure 18, it was confirmed that the output voltage of the antenna module 30 increased discontinuously in response to light rainfall with an hourly precipitation of 0 mm. Furthermore, as explained with reference to Figure 1, the amount of precipitation could be calculated by statistically processing the voltage fluctuation component. The discontinuous increase in the output voltage of the antenna module 30 is thought to have occurred due to the merging of multiple raindrops RD attached to the transparent capsule (container 20). Before performing the statistical processing, the output voltage of the antenna module 30 was subjected to a filtering process, which will be described later, with reference to Figures 19 and 20.

[0149] As described above, with the observation device 110 of this embodiment, the output voltage of the antenna module 30 fluctuated even in the case of light rainfall. Furthermore, it was possible to calculate the amount of precipitation even in the case of light rainfall.

[0150] Figure 19 shows yet another example of the results obtained by installing the observation device 110 according to this embodiment outdoors and taking measurements. In Figure 19, the vertical axis represents the voltage value and the horizontal axis represents the time. Furthermore, Graph 7 G7 shows the measurement results. Specifically, Graph 7 G7 shows the output voltage of the antenna module 30 during the time period when no rainfall was detected at the Sapporo Regional Meteorological Observatory (from 12:00 to 13:00).

[0151] Figure 20 is an enlarged view of a portion of the graph (Graph G7, 7th graph) from Figure 19. In Figure 20, the vertical axis represents voltage values, and the horizontal axis represents time. Specifically, Figure 20 shows an enlarged view of the output voltage of the antenna module 30 recorded between 12:00 and 12:02.

[0152] As shown in Figures 19 and 20, when there was no precipitation, noise of approximately ±10 mV sometimes occurred in the output voltage of the antenna module 30. This noise could be removed by filtering. Therefore, by using the observation device 110 of this embodiment, it was possible to observe that there was no precipitation.

[0153] Specifically, the voltage spikes generated in the output voltage of the antenna module 30 due to raindrops RD adhering to the transparent capsule (container 20) showed a characteristic of rising sharply and then gradually decreasing. In contrast, the noise voltage spikes showed a characteristic of rising sharply and then rapidly decreasing. Therefore, a computer program was created to perform a filtering process to remove the voltage spikes that rise sharply and then rapidly decrease, thereby removing the noise voltage spikes through this filtering process.

[0154] Figure 21 shows the relationship between the hourly cumulative value calculated based on actual measurements taken by installing the observation device 110 of this embodiment outdoors, and the hourly precipitation measured separately. In Figure 21, the horizontal axis shows the hourly cumulative value of the voltage fluctuation component, and the vertical axis shows the hourly precipitation. The black circles indicate the actual measurement results of the voltage fluctuation component. Specifically, the output voltage of the antenna module 30 was recorded for about one month using the observation device 110 of this embodiment. Then, the hourly cumulative value of the voltage fluctuation component was calculated as explained with reference to Figure 1.

[0155] Graph G8 is a quadratic regression line obtained from hourly precipitation measured by tipping bucket rain gauges during the same period. As shown in Figure 21, the coefficient of determination R between the hourly integrated value of the voltage fluctuation component and the hourly precipitation is R. ２ The value was "0.96". Therefore, it was confirmed that there is a correlation between the hourly integrated value of the voltage fluctuation component and the hourly precipitation. Specifically, there was a quadratic regression relationship between the hourly integrated value of the voltage fluctuation component and the hourly precipitation. Therefore, it was confirmed that the hourly precipitation can be obtained with greater accuracy by converting the hourly integrated value of the voltage fluctuation component with a quadratic equation.

[0156] This invention can be used for observing precipitation particles.

[0157] 10 First holding member (holding member) 20 Enclosure 21 Wall 21a Inner surface 21b Outer surface 22 Inner space 30 Antenna module 40 Second holding member (base) 50 Support member 60 Cable 70 Recording device 80 Analysis device 100 Observation system 110 Observation device 200 Information processing device 205 Installation position determination support program A Area B Area C Area E Electromagnetic wave h Distance H Distance RD Raindrop

Claims

1. A method for manufacturing an observation device for observing precipitation particles using transmitted electromagnetic waves and electromagnetic waves reflected by precipitation particles, comprising the steps of: preparing a containment container; preparing an antenna module that transmits electromagnetic waves and receives the electromagnetic waves reflected by the containment container and the electromagnetic waves reflected by precipitation particles; a theoretical formula that converts a function showing the relationship between the electromagnetic waves transmitted from the antenna module and the electromagnetic waves reflected by the containment container into a function having the dielectric constant of the wall of the containment container, the thickness of the wall, and the installation position in which the antenna module is installed within the containment container as variables; and outputting information regarding the installation position based on the value of the dielectric constant of the wall and the value of the thickness of the wall; preparing a holding member for holding the antenna module; and housing the antenna module and the holding member in the containment container and installing the antenna module at the installation position.

2. A method for manufacturing an observation apparatus according to claim 1, further comprising the step of electrically connecting the antenna module and a recording device, wherein the antenna module outputs a voltage based on the electromagnetic waves emitted from the antenna module and the electromagnetic waves received by the antenna module, and the recording device records the voltage output from the antenna module.

3. The method for manufacturing the observation device according to claim 1 or claim 2, wherein the portion of the outer surface of the wall of the containment container through which the electromagnetic waves pass is convex curved.

4. A method for manufacturing an observation device according to claim 1 or claim 2, wherein the theoretical formula includes: Maxwell's equations for the electromagnetic waves emitted from the antenna module; Maxwell's equations for the electromagnetic waves reflected at the boundary between the inner surface of the wall portion of the containment container and the internal space of the containment container; Maxwell's equations for the electromagnetic waves incident on the wall portion of the containment container; Maxwell's equations for the electromagnetic waves reflected at the boundary between the outer surface of the wall portion of the containment container and the external space of the containment container; and Maxwell's equations for the electromagnetic waves transmitted from the wall portion of the containment container to the external space.

5. An observation device for observing precipitation particles using transmitted electromagnetic waves and electromagnetic waves reflected by precipitation particles, comprising: a containment container having a wall that separates an internal space from an external space; an antenna module that transmits electromagnetic waves and receives the electromagnetic waves reflected by the containment container and the electromagnetic waves reflected by the precipitation particles; and a holding member for holding the antenna module, wherein the containment container houses the holding member for holding the antenna module in the internal space; the antenna module is installed at an installation position within the containment container determined based on a predetermined theoretical formula, the dielectric constant of the wall, and the thickness of the wall, and the predetermined theoretical formula converts a function showing the relationship between the electromagnetic waves transmitted from the antenna module and the electromagnetic waves reflected by the containment container into a function having the dielectric constant of the wall, the thickness of the wall, and the installation position as variables.

6. The observation apparatus according to claim 5, further comprising a recording device electrically connected to the antenna module, wherein the antenna module outputs a voltage based on the electromagnetic waves transmitted from the antenna module and the electromagnetic waves received by the antenna module, and the recording device records the voltage output from the antenna module.

7. The observation device according to claim 5 or 6, wherein the portion of the outer surface of the wall of the containment container through which the electromagnetic waves pass is convex.

8. The observation apparatus according to claim 5 or claim 6, wherein the antenna module installed at the installation position transmits the electromagnetic waves mainly in a vertically upward direction.

9. The observation apparatus according to claim 5 or 6, wherein the theoretical formula includes: Maxwell's equations for the electromagnetic waves emitted from the antenna module; Maxwell's equations for the electromagnetic waves reflected at the boundary between the inner surface of the wall of the containment container and the internal space; Maxwell's equations for the electromagnetic waves incident on the wall of the containment container; Maxwell's equations for the electromagnetic waves reflected at the boundary between the outer surface of the wall of the containment container and the external space; and Maxwell's equations for the electromagnetic waves transmitted from the wall of the containment container to the external space.

10. A computer program that causes a computer to function to output information regarding the installation position of an antenna module in an observation device that observes precipitation particles using transmitted electromagnetic waves and electromagnetic waves reflected by precipitation particles, wherein the observation device comprises: the antenna module; a holding member for holding the antenna module; and a housing container having a wall that partitions an internal space and an external space, the internal space housing the holding member for holding the antenna module; the antenna module transmits electromagnetic waves and receives the electromagnetic waves reflected by the housing container and the electromagnetic waves reflected by precipitation particles; the installation position indicates a position in the housing container where the antenna module is installed; and the computer program, upon inputting the dielectric constant value of the wall and the thickness value of the wall, causes the computer to function to output information regarding the installation position based on a predetermined theoretical formula, the dielectric constant value of the wall, and the thickness value of the wall. The aforementioned predetermined theoretical formula is a computer program that converts a function showing the relationship between the electromagnetic waves emitted from the antenna module and the electromagnetic waves reflected by the housing into a function having the dielectric constant of the wall, the thickness of the wall, and the installation position as variables.

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