Electric field strength measuring device

Abstract

To provide an electric field strength measuring device which enables a three-dimensional electric field strength distribution to be obtained and enables influence on directivity of a receiving unit to be reduced.SOLUTION: An electric field strength measuring device 1 comprises a flight vehicle 2 and a measurement unit 3 mounted in the flight vehicle 2. The measurement unit 3 includes a digital terrestrial broadcasting reception antenna 31 as a receiving unit capable of receiving radio waves, a spectral analyzer 32 as a measurement unit body measuring electric field strength on the basis of received information of the digital terrestrial broadcasting reception antenna 31, and a GPS device 321 as a position acquisition unit acquiring self-position information. The digital terrestrial broadcasting reception antenna 31 includes a belt-like first power feed element 311, a belt-like second power feed element 312, and a belt-like passive element 313. The first power feed element 311, the second power feed element 312, and the passive element 313 are arranged in parallel in the order stated while being spaced apart from each other, the dimension of the first power feed element 311 is larger than the second power feed element 312 and the dimension of the second power feed element 312 is larger than the passive element 313 in the longitudinal direction.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a field intensity measuring device. [Background technology]

[0002] In general, the characteristics of antennas for broadcast transmission, etc. are measured at the time of shipment, but there is a possibility that the characteristics may change when the antenna is actually installed. Therefore, a method has been proposed in which a field strength measuring device is mounted on a field strength measuring vehicle and the vehicle is driven to measure the field strength distribution of the antenna (see, for example, Patent Document 1). In the method described in Patent Document 1, a GPS receiver is mounted on the field strength measuring vehicle, and data processing is performed to associate the measured field strength data with position data. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 5-302944 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the method described in Patent Document 1 could obtain the distribution of electric field strength on the ground, but could not obtain a three-dimensional distribution of electric field strength. Therefore, a method of mounting an electric field strength measuring device on an aircraft such as a drone could be considered, but there is a possibility that the propeller part for flying may affect the directivity of the antenna (receiving part) of the electric field strength measuring device.

[0005] The present invention has been made in consideration of the above-mentioned problems, and its object is to provide a field strength measuring device that can obtain a three-dimensional field strength distribution and reduce the effect on the directivity of the receiving unit. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the electric field strength measuring device of the present invention is an electric field strength measuring device comprising an aircraft and a measurement unit mounted on the aircraft, wherein the measurement unit has a receiving unit capable of receiving radio waves, a measurement unit main body that measures electric field strength based on information received by the receiving unit, and a position acquisition unit that acquires self-position information, wherein the receiving unit has a strip-shaped first feed element, a strip-shaped second feed element, and a strip-shaped parasitic element, wherein the first feed element, the second feed element, and the parasitic element are arranged in this order in parallel with a gap between them, and wherein, in the longitudinal direction, the first feed element is larger in dimension than the second feed element, and the second feed element is larger in dimension than the parasitic element.

[0007] In an electric field strength measuring device according to one embodiment of the present invention, the receiving unit is attached to the aircraft so that it can rotate at least 90 degrees around an axis of rotation along the direction in which the first feed element, the second feed element, and the parasitic element are aligned.

[0008] In an electric field strength measuring device according to one embodiment of the present invention, the receiving unit has a holding plate portion on which the first feeding element, the second feeding element, and the parasitic element are arranged, and a through hole is formed in the holding plate portion. Effect of the Invention

[0009] According to the electric field intensity measuring device of the present invention, it is possible to obtain a three-dimensional electric field intensity distribution and reduce the effect on the directivity of the receiving section. [Brief description of the drawings]

[0010] [Figure 1] 1 is a block diagram of a field intensity measuring device according to an embodiment of the present invention. [Diagram 2] 1 is a perspective view of a receiving section of a field intensity measuring device according to an embodiment of the present invention; [Diagram 3] 3 is a side view of the receiving section in the electric field intensity measuring device according to the embodiment of the present invention when the propeller section is not rotating. FIG. [Figure 4]3 is a side view of a receiving section in a state where a propeller section is rotating in the electric field intensity measuring device according to the embodiment of the present invention. FIG. [Diagram 5] 3 is a plan view of a receiving section in a state where a propeller section is not rotating in the electric field intensity measuring device according to the embodiment of the present invention. FIG. [Figure 6] 3 is a plan view of a receiving section in a state where a propeller section is rotating in the electric field intensity measuring device according to the embodiment of the present invention; FIG. [Figure 7] 3 is a side view of a receiving section in a field intensity measuring device according to an embodiment of the present invention in a state compatible with vertical polarization. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0012] FIG. 1 is a block diagram of an electric field strength measuring device 1 according to an embodiment of the present invention, FIG. 2 is an oblique view of a terrestrial digital receiving antenna 31 as a receiving section of the electric field strength measuring device 1, FIG. 3 is a side view of the terrestrial digital receiving antenna 31 in a state in which the propeller section is not rotating in the electric field strength measuring device 1, FIG. 4 is a side view of the terrestrial digital receiving antenna 31 in a state in which the propeller section is rotating in the electric field strength measuring device 1, FIG. 5 is a plan view of the terrestrial digital receiving antenna 31 in a state in which the propeller section is not rotating in the electric field strength measuring device 1, FIG. 6 is a plan view of the terrestrial digital receiving antenna 31 in a state in which the propeller section is rotating in the electric field strength measuring device 1, and FIG. 7 is a side view of the terrestrial digital receiving antenna 31 in a state corresponding to vertical polarization in the electric field strength measuring device 1.

[0013] 1 and 2, the electric field intensity measuring device 1 according to the embodiment of the present invention includes an aircraft 2 and a measuring unit 3 mounted on the aircraft 2. The measuring unit 3 includes a terrestrial digital receiving antenna 31 as a receiving unit capable of receiving radio waves, a spectrum analyzer 32 as a measuring unit main body that measures electric field intensity based on information received by the terrestrial digital receiving antenna 31, and a GPS device 321 as a position acquiring unit that acquires self-position information. The terrestrial digital receiving antenna 31 includes a strip-shaped first feed element 311, a strip-shaped second feed element 312, and a strip-shaped parasitic element 313. The first feed element 311, the second feed element 312, and the parasitic element 313 are arranged in this order in parallel with a space between them. In the longitudinal direction, the first feed element 311 is larger in size than the second feed element 312, and the second feed element 312 is larger in size than the parasitic element 313. The electric field intensity measuring device 1 will be specifically described below.

[0014] The field intensity measuring device 1 is for measuring the directivity pattern of a broadcasting transmission antenna installed in, for example, a transmitting station or relay station of terrestrial digital broadcasting. In the following description, it is assumed that the measurement results of the field intensity measuring device 1 are stored in an SD card 322 serving as a storage unit, but the measurement results may be transmitted to an external device by wireless communication, for example. Information output to the outside by the field intensity measuring device 1 may be the measurement results before processing, or may be information that has been subjected to a predetermined process (for example, a field intensity map).

[0015] The flying object 2 is, for example, a drone, which has a drone body 21 and a camera 22 mounted on the drone body, and is capable of unmanned remote control. The drone body 21 has multiple propeller parts, and the attitude and moving speed of the flying object 2 can be adjusted by independently controlling the rotation speed of each propeller part. The multiple propeller parts have rotation axes that are approximately parallel to each other, and a state in which these rotation axes are approximately aligned in the vertical direction is called the normal attitude of the flying object 2. Hereinafter, the direction of the rotation axis (up and down direction) in the flying object 2 is defined as the Z direction, one direction in a plane perpendicular to the Z direction is defined as the X direction, and a direction perpendicular to both the Z direction and the X direction is defined as the Y direction. In other words, the X direction, the Y direction, and the Z direction are determined based on the flying object 2, and are determined regardless of the vertical direction or the horizontal plane.

[0016] The measurement unit 3 has a terrestrial digital receiving antenna 31 as a receiving section capable of receiving radio waves, and a spectrum analyzer (electrical measuring device) 32 as a measuring section main body that measures electric field intensity based on information received by the terrestrial digital receiving antenna. The spectrum analyzer 32 is provided with a GPS device 321 as a position acquisition section that acquires self-position information, and an SD card 322 as a removable storage section.

[0017] As shown in FIG. 2, the terrestrial digital receiving antenna 31 has two antenna parts 31A and 31B, and each of the antenna parts 31A and 31B has a strip-shaped first feeding element 311, a strip-shaped second feeding element 312, a strip-shaped parasitic element 313, a holding plate part 314 on which these elements 311 to 313 are arranged, and a connection line 315 connecting the first feeding element 311 and the second feeding element 312. The terrestrial digital receiving antenna 31 is attached to the flying object 2 so as to be rotatable by 90° around a rotation axis along the X direction. The terrestrial digital receiving antenna 31 may be rotatable by 90° or more. In the following, a state corresponding to a horizontally polarized wave and a state corresponding to a vertically polarized wave will be described separately.

[0018] FIG. 2 shows a state corresponding to horizontal polarization. The holding plate 314 is formed in a flat plate shape and is provided along the XY plane, and the strip-shaped elements 311 to 313 arranged thereon are also aligned along the XY plane. The longitudinal direction of the elements 311 to 313 coincides with the Y direction. The first feed element 311, the second feed element 312, and the parasitic element 313 are arranged in this order in parallel with a gap between them. That is, the first feed element 311, the second feed element 312, and the parasitic element 313 are arranged in the X direction. When the flying object 2 is in the normal attitude, the elements 311 to 313 are arranged in one direction in the horizontal plane. The Y direction dimension of the first feed element 311 is larger than the Y direction dimension of the second feed element 312, and the Y direction dimension of the second feed element 312 is larger than the Y direction dimension of the parasitic element 313.

[0019] The holding plate parts 314 of the two antenna parts 31A, 31B are arranged in parallel with a gap therebetween in the Z direction, and a column member or the like may be provided between them as appropriate. A plurality of through holes 314A are formed in a non-arrangement area of ​​the holding plate part 314 where the elements 311 to 313 are not provided. Note that the through holes 314A are not shown in figures other than FIG. 2. There may be only one through hole, and the number is not limited. The shape of the through hole may be circular or another shape such as a polygonal shape.

[0020] When the digital terrestrial broadcasting receiving antenna 31 is rotated 90 degrees from the state shown in Fig. 2, it becomes in a state corresponding to vertical polarization. That is, the elements 311 to 313 and the holding plate part 314 become in a state along the ZX plane (see Fig. 7).

[0021] The electric field intensity measuring device 1 as described above is capable of measuring the electric field intensity while changing the measurement position by performing measurements with the measurement unit 3 while moving with the flying object 2. At this time, the self-position information (three-dimensional information) obtained by the GPS device 321 and the measurement information obtained by the spectrum analyzer 32 are associated and stored in the SD card 322. The flight path of the flying object 2 may be set appropriately. For example, the flying object 2 may be rotated at the same height while performing measurements, or the flying object 2 may be moved only in the vertical direction while performing measurements, or these operations may be combined.

[0022] The directivity of the terrestrial digital receiving antenna 31 when measuring the electric field intensity while flying the flying object 2 as described above will be described with reference to Figs. 3 to 7. Figs. 3 and 5 show the flying object 2 in a state where the propeller part is not rotating and not flying, and Figs. 4 and 6 show the flying object 2 in a state where the propeller part is rotating and flying. Figs. 3 and 4 show the appearance as seen from the Y direction, and Figs. 5 and 6 show the appearance as seen from the Z direction. In Figs. 3 and 4, the propeller part is located above the antenna part 31A, and in Figs. 5 and 6, the propeller part is located at a position sandwiching the terrestrial digital receiving antenna 31 from the left and right. In either case, the terrestrial digital receiving antenna 31 is arranged in a manner that corresponds to horizontal polarization.

[0023] Since elements 311 to 313 have the above-described arrangement and dimensional relationship, the directivity of terrestrial digital broadcasting receiving antenna 31 is concentrated, and although the directivity changes slightly as the propeller part rotates, it is easy to maintain the directivity in the X direction, which is the arrangement direction.

[0024] 7 shows the directivity of the terrestrial digital receiving antenna 31 when the antenna is arranged for vertical polarization and the propeller part is not rotating. In this case as well, the directivity of the terrestrial digital receiving antenna 31 is unlikely to change even if the propeller part rotates.

[0025] According to the electric field strength measuring device 1 of the embodiment of the present invention as described above, the first feed element 311, the second feed element 312 and the parasitic element 313 are arranged in this order facing each other with a gap between them, and in a direction perpendicular to the arrangement direction (X direction), the first feed element 311 has a larger dimension than the second feed element 312, which in turn has a larger dimension than the parasitic element 313. As a result, a three-dimensional electric field strength distribution can be obtained and the impact on the directivity of the terrestrial digital broadcasting receiving antenna 31 as a receiving section can be reduced.

[0026] Furthermore, the terrestrial digital broadcasting receiving antenna 31 is attached to the flying object 2 so as to be rotatable at least 90 degrees around the X direction as the axis of rotation, thereby enabling it to handle both horizontally polarized waves and vertically polarized waves.

[0027] Furthermore, by forming the through hole 314A in the held area of ​​the holding plate portion 314, the weight of the digital terrestrial broadcasting receiving antenna 31 can be reduced and the aerodynamic characteristics can be improved.

[0028] Although the embodiment of the present invention has been described above, the present invention is not limited to the electric field intensity measuring device according to the embodiment of the present invention, and includes all aspects included in the concept and scope of the claims of the present invention. In addition, each configuration may be appropriately and selectively combined to achieve at least a part of the above-mentioned problems and effects. For example, the shape, material, arrangement, size, etc. of each component in the above embodiment may be appropriately changed depending on the specific use of the present invention.

[0029] For example, in the above embodiment, the terrestrial digital receiving antenna 31 is attached to the flying object 2 so as to be rotatable by at least 90° with the X direction as the rotation axis direction, but the terrestrial digital receiving antenna may not be rotatable with respect to the flying object. That is, the electric field intensity measuring device may be compatible with only either horizontally polarized waves or vertically polarized waves, or it may be compatible with both horizontally polarized waves and vertically polarized waves by adjusting the attitude of the flying object.

[0030] In the above embodiment, through-hole 314A is formed in the held area of ​​holding plate 314, but the presence or absence of a through-hole may be appropriately selected depending on, for example, the material and strength of the holding plate. In addition, the configuration for holding the feed element and the parasitic element is not limited to the one using a holding plate. [Explanation of symbols]

[0031] 1...field intensity measuring device, 2...aircraft vehicle, 3...measurement unit, 31...terrestrial digital receiving antenna (receiving section), 311...first feeding element, 312...second feeding element, 313...parasitic element, 314...holding plate section, 314A...through hole, 32...spectrum analyzer (measuring section main body), 321...GPS device (position acquisition section)

Claims

1. An electric field strength measuring device including an aircraft and a measurement unit mounted on the aircraft, The measurement unit includes a receiver capable of receiving radio waves, a measurement unit main body that measures electric field intensity based on information received by the receiver, and a position acquisition unit that acquires self-position information; the receiving section includes a strip-shaped first feed element, a strip-shaped second feed element, and a strip-shaped parasitic element; the first feed element, the second feed element, and the parasitic element are arranged in this order in parallel with one another at intervals, and in a longitudinal direction, the first feed element is larger in size than the second feed element, and the second feed element is larger in size than the parasitic element; The electric field strength measuring device is characterized in that the side of the first feed element in the arrangement direction of the first feed element, the second feed element, and the parasitic element of the receiving unit faces the propeller portion of the aircraft.

2. The electric field strength measuring device according to claim 1, characterized in that the receiving unit is attached to the aircraft so as to be rotatable at least 90 degrees around a rotation axis along a direction in which the first feed element, the second feed element, and the parasitic element are arranged.

3. the receiving unit has a holding plate on which the first feed element, the second feed element, and the parasitic element are arranged, 3. The electric field intensity measuring device according to claim 1, wherein the holding plate portion has a through hole formed therein.

Images