JPH11194172A - Loop antenna and electromagnetic wave generating-source locating system using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely detect the direction to an electromagnetic wave generating source, such as a thunderbolt, earthquake, etc., over a wide frequency range. SOLUTION: When an electromagnetic wave RW1 caused by a thunderbolt, etc., and having a strong magnetic-field signal strength and a high frequency arrives from the horizontal direction, output voltages are respectively generated across the first and fourth terminals 1 and 4 of orthogonal first and second antennas 10 and 20 and across the second and fifth terminals 2 and 5 of the antennas 10 and 20 which are the intermediate terminals of the antennas 10 and 20. From the output voltages, the arriving azimuth of the electromagnetic wave RW1 can be measured. When another electromagnetic wave RW2 caused b an earthquake, etc., and having a low magnetic-field signal strength and a weak frequency arrives from the horizontal direction, output voltages are respectively generated across the first and fourth terminals 1 and 4 and across the third and sixth terminals 3 and 6 of the antennas 10 and 20. From the output voltages, the arriving azimuth of the wave RW2 can be measured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a loop antenna for detecting electromagnetic waves generated from an electromagnetic wave source such as lightning or an earthquake, and an electromagnetic wave for measuring the position of the electromagnetic wave source using the loop antenna. It relates to a source location system.

[0002]

2. Description of the Related Art Conventionally, an orthogonal loop antenna has been known as a device for detecting a magnetic field component of an electromagnetic field (that is, an electromagnetic wave) generated by a lightning strike as a ground discharge lightning. The orthogonal loop antenna includes a loop-shaped first antenna and a loop-shaped second antenna orthogonal to the first antenna.
This is an antenna installed vertically to the ground. In this loop antenna, when an electromagnetic wave arrives from the horizontal direction with respect to the ground, an induced voltage is generated by the electromagnetic wave and the electromagnetic wave is received. In the conventional electromagnetic wave source location system using such an orthogonal loop antenna, a plurality of orthogonal loop antennas are installed over a wide area. When an electromagnetic wave is generated in the area due to a lightning strike or the like, the electromagnetic wave is received by a plurality of loop antennas, and the direction of the electromagnetic wave source such as a lightning strike is calculated from the ratio of the peak values of the received signal. The location and size of the source are specified.

[0003]

However, the conventional orthogonal loop antenna and the electromagnetic wave source position locating system using the same have the following problems. A conventional orthogonal loop antenna includes a loop-shaped first antenna in which an antenna conductor is wound several times, and a loop-shaped second antenna in which an antenna conductor is wound several times orthogonal to the antenna. Then, by detecting an induced voltage generated by the electromagnetic wave arriving from the horizontal direction, the arrival direction of the electromagnetic wave is detected. Therefore, when the electromagnetic wave source has a strong magnetic field signal strength such as a lightning strike, the direction of the electromagnetic wave source can be detected. However, for an electromagnetic wave having a small magnetic field signal strength, it is difficult to detect the direction of the electromagnetic wave source. is there.

[0004] In particular, in recent years, expectations for earthquake prediction are high, and this is also a public desire. Although various observations and researches have been carried out to obtain a certain result, they are still insufficient, and are influential in leading to earthquake prediction. The collection of reliable observation data is awaited. As one observation means for detecting this earthquake prediction, for example, the use of electromagnetism has been proposed.
According to research reports that electromagnetic anomalous phenomena often occur several hours to several tens of days before an earthquake, a discharge is generated due to the destruction of the earth's crust, and this discharge generates low-frequency electromagnetic waves. It is intended to predict the occurrence of an earthquake by receiving this electromagnetic wave. However, the generation of electromagnetic waves, which is a precursor to the occurrence of an earthquake, has an extremely low magnetic field signal intensity compared to electromagnetic waves due to lightning that also occurs in other natural environments. There is also a large amount of electromagnetic wave noise, such as corona discharge, which is generated periodically. Therefore, it is difficult to efficiently detect only the electromagnetic wave of the precursor of an earthquake while discriminating them by a conventional method using an orthogonal loop antenna.

SUMMARY OF THE INVENTION The present invention solves the problems of the prior art, and detects not only electromagnetic waves having a large magnetic field signal intensity generated by lightning or the like but also electromagnetic waves having a small magnetic field signal intensity generated by an earthquake or the like. Another object of the present invention is to provide a loop antenna capable of reliably receiving a signal and an electromagnetic wave source position locating system using the loop antenna.

[0006]

According to a first aspect of the present invention, a first antenna having a loop shape and a second antenna having a loop shape orthogonal to the first antenna are provided. However, in a loop antenna installed in a direction perpendicular to the ground, the first antenna is configured by a first antenna conductor and a second antenna conductor as follows, and the second antenna is , The third antenna conductor and the fourth
Antenna conductor.

The first antenna conductor has one end connected to the first terminal and the other end connected to the second terminal, and is wound in a direction perpendicular to the ground, and has a first magnetic field signal strength. When a first electromagnetic wave of a first frequency band arrives from a horizontal direction, a first induced voltage generated by the first electromagnetic wave is output from the first and second terminals.
The second antenna conductor has one end connected to the second terminal and the other end connected to the third terminal, and is wound along the first antenna conductor, and the second antenna conductor is different from the first electromagnetic wave.
When the second electromagnetic wave of the second frequency band having the magnetic field signal intensity of the second electromagnetic wave arrives from the horizontal direction, the second induced voltage generated by the second electromagnetic wave is output from the first terminal and the third terminal. Is what is done. A third antenna conductor, the second antenna having one end connected to the fourth terminal and the other end connected to the fifth terminal, and wound in a direction perpendicular to the ground; Comes from the horizontal direction, a third induced voltage generated by the first electromagnetic wave is output from the fourth and fifth terminals. Further, the fourth antenna conductor has one end connected to the fifth terminal and the other end connected to the sixth terminal.
When the second electromagnetic wave arrives from the horizontal direction, a fourth induced voltage generated by the second electromagnetic wave is output from the fourth terminal and the sixth terminal. Things.

In the invention according to claim 2, in the loop antenna according to claim 1, the number of turns Na and the conductor diameter Da of the first and third antenna conductors and the number of turns Nb and Nb of the second and fourth antenna conductors are provided. The conductor diameter Db is set to have a relationship of Na <Nb and Da> Db. By adopting such a configuration, for example, when a first electromagnetic wave of a first frequency band having a large first magnetic field signal intensity generated from an electromagnetic wave source such as a lightning strike arrives from the horizontal direction, the first electromagnetic wave is transmitted to the first frequency band. When a first induced voltage is generated in the antenna conductor,
A third induced voltage is generated in the third antenna conductor, and
Is output from the first and second terminals, and the third induced voltage is output from the fourth and fifth terminals. Thus, the direction of the electromagnetic wave generation source can be detected by receiving the first electromagnetic wave. Further, when a second electromagnetic wave of a second frequency band having a small second magnetic field signal intensity generated from an electromagnetic wave source such as an earthquake arrives from the horizontal direction,
A second induced voltage is generated in the second antenna conductor, a fourth induced voltage is generated in the fourth antenna conductor, and the second induced voltage is output from the first and third terminals. , The fourth induced voltage is output from the fourth and sixth terminals. Thus, the direction of the electromagnetic wave generation source can be detected by receiving the second electromagnetic wave.

According to a third aspect of the present invention, in the loop antenna, the first and second antennas of the first or second aspect are horizontal to the ground and orthogonal to the first and second antennas. And the third antenna is configured as follows. The third antenna has an antenna conductor which is connected to the seventh terminal at one end and connected to the eighth terminal at the other end and wound in a horizontal direction with respect to the ground, and has a third magnetic field signal strength. When the third electromagnetic wave of the third frequency band having
A third induced voltage generated by the third electromagnetic wave is output from the seventh and eighth terminals.

According to a fourth aspect of the present invention, in the loop antenna of the third aspect, an intermediate terminal is extended from an intermediate portion of the antenna conductor forming the third antenna. In the invention according to claim 5, in the loop antenna according to claim 4, the conductor diameter of the antenna conductor from the seventh terminal to the intermediate terminal and the conductor diameter of the antenna conductor from the intermediate terminal to the eighth terminal. The conductor diameter is set to a different value. By adopting such a configuration, for example, when a third electromagnetic wave of a third frequency band having a small third magnetic field signal intensity generated from an electromagnetic wave generation source such as an earthquake arrives from the vertical direction, the third electromagnetic wave is generated. A third induced voltage is generated in the antenna, and the third induced voltage is output from the seventh and eighth terminals. Thereby, the direction of the electromagnetic wave generation source can be detected by receiving the third electromagnetic wave.

According to a sixth aspect of the present invention, in the electromagnetic wave source position locating system, a plurality of first antennas of the loop antenna according to any one of the first to sixth aspects are installed on the ground in a north-south direction. A configuration in which the direction of the electromagnetic wave generation source is detected by the plurality of loop antennas, and the position of the electromagnetic wave generation source detected at the same time by at least two of the plurality of loop antennas is detected. I have to. By adopting such a configuration, when an electromagnetic wave is generated from an electromagnetic wave source such as a lightning strike having a large magnetic field signal strength or an electromagnetic wave source such as an earthquake having a small magnetic field signal strength, the electromagnetic wave is generated by at least two loop antennas at the same time. Is received. From the intersection of the directions of the electromagnetic wave sources received at the same time by the two loop antennas, the position and the like of the electromagnetic wave sources are measured.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment FIG. 1 is a schematic configuration diagram of an orthogonal loop antenna according to a first embodiment of the present invention. The orthogonal loop antenna is installed in a direction perpendicular to the ground, and has first, second, third, fourth, fifth, and sixth terminals for extracting an induced voltage induced by an incoming electromagnetic wave RW. 1,2,3,
4, 5, and 6. First terminal 1 and third terminal 3
, A first antenna 10 having a rectangular loop shape oriented in the north-south direction is connected, and the first antenna 10 is connected between the third terminal 3 and the sixth terminal 6. A second antenna 20 having a rectangular loop shape orthogonally directed in the east-west direction is connected.

The first antenna 10 has a first antenna conductor 11 connected at one end to the first terminal 1 and connected at the other end to the second terminal 2 and wound in a direction perpendicular to the ground.
And a second antenna conductor 12 having one end connected to the second terminal 2 and the other end connected to the third terminal 3 and wound along the first antenna conductor 11. . The first antenna conductor 11 has a conductor having a conductor diameter D1 and a winding number N1.
(For example, 7 to 10 times), and a first frequency band (for example, 1 KHz to 300 KHz or several KHz) having a large first magnetic field signal strength such as a lightning strike.
When the first electromagnetic wave RW1 (to several MHz) arrives from the horizontal direction with respect to the ground, the first induced voltage generated by the first electromagnetic wave RW1 is applied to the first terminal 1 and the second terminal 2.
Is output from In the second antenna conductor 12, the conductor having the conductor diameter D2 has the number of turns N2 (for example, 700
And a second electromagnetic wave R of a second frequency band (for example, about 0.1 KHz to 10 KHz) having a small second magnetic field signal strength such as an earthquake.
When W2 arrives from the horizontal direction, the second electromagnetic wave RW2
Is generated from the first terminal 1 and the third terminal 3.

The second antenna 20 has a third antenna conductor 21 connected at one end to the fourth terminal 4 and connected at the other end to the fifth terminal 5 and wound in a direction perpendicular to the ground.
And a fourth antenna conductor 22 having one end connected to the fifth terminal 5 and the other end connected to the sixth terminal 6 and wound along the third antenna conductor 21. . The third antenna conductor 21 is configured by winding a conductor having a conductor diameter D3 (e.g., equal to the conductor diameter D1) with a number of turns N3 (e.g., equal to the number of turns N1). When the first electromagnetic wave RW1 of the first frequency band having the magnetic field signal strength arrives from the horizontal direction, a third induced voltage generated by the first electromagnetic wave RW1 is generated from the fourth terminal 4 and the fifth terminal 5. It is output.
The fourth antenna conductor 22 has a conductor having a conductor diameter D4 (e.g., equal to the conductor diameter D2) having a number of turns N4 (e.g.
) And a small second
When the second electromagnetic wave RW2 of the second frequency band having the magnetic field signal strength of the second electromagnetic wave arrives from the horizontal direction, the second electromagnetic wave R
The fourth induced voltage generated by W2 is output from the fourth terminal 6 and the sixth terminal 6.

FIGS. 2A and 2B are explanatory diagrams of the principle of azimuth measurement using the orthogonal loop antenna of FIG. 1. FIG. 2A shows the first antenna conductor 11 of FIG. Number of turns N
1 is a perspective view of 1), and FIG. 2B is a plan view of the first antenna conductor 11. The principle of azimuth measurement using the first antenna conductor 11 will be described with reference to FIGS.

For example, the first antenna conductor 11 having one turn
Has a rectangular shape composed of vertical portions 11a and 11c and horizontal portions 11b and 11d, and has one end connected to the first terminal 1 and the other end connected to the second terminal 2, respectively. When an electromagnetic wave RW arrives from a horizontal direction with respect to a first antenna conductor 11 installed in a direction perpendicular to the ground, induced voltages e1 and e2 are applied to vertical portions 11a and 11c on both sides of the first antenna conductor 11, respectively. But does not occur in the horizontal parts 11b and 11d. Therefore, the output voltage between the first terminal 1 and the second terminal 2 becomes the vector sum of FIG. 2A. In this case, the output voltage is a series connected in the opposite direction, and the difference between the absolute values of the voltages ( e1-e2). The phase of the induced voltage e1 of the vertical portion 11a is advanced by Lcos θ from the center point O of FIG. 2B, and the induced voltage e2 of the vertical portion 11c is Lcos
The phase is delayed by θ. As a result, when the angle θ is 0 °, the phase difference is the largest, and the first terminal 1 and the second terminal 2
Is large, and when the angle θ is 90 °, there is no phase difference and the output voltage becomes zero. Angle θ is 90
When the angle is larger than °, a phase difference occurs again. Arrival direction (angle θ) of electromagnetic wave RW with respect to first antenna conductor 11
Is changed from the first terminal 1 and the second terminal 2 to c
The output voltage changes in proportion to osθ. This output voltage is proportional to the number of turns N1 of the first antenna conductor 11 and the antenna area if the wavelength of the electromagnetic wave RW is constant. Therefore, from the output voltages of the first terminal 1 and the second terminal 2,
The arrival direction (angle θ) of the electromagnetic wave RW can be detected.

FIG. 3 is a schematic configuration diagram of a receiving side circuit connected to the first to sixth terminals 1 to 6 of the loop antenna of FIG. 1 for detecting the arrival direction of the electromagnetic wave RW. This receiving side circuit includes a first electromagnetic wave extraction circuit 41 connected to first, second, fourth, and fifth terminals 1, 2, 4, and 5 of the loop antenna of FIG. , Fourth and sixth terminals 1,
And a second electromagnetic wave extraction circuit 42 connected to 3, 4, and 6. The first electromagnetic wave extraction circuit 41 receives the output voltages of the first, second, fourth, and fifth terminals 1, 2, 4, 5, and 5 and has a first magnetic field signal strength such as a lightning strike. 1
A circuit for identifying the magnetic field waveform of the first electromagnetic wave RW1 in the frequency band of and extracting only the first electromagnetic wave RW1;
It is composed of a bandpass filter and the like. The second electromagnetic wave extraction circuit 42 includes first, third, fourth, and sixth terminals 1, 3, 4,
6, the second electromagnetic wave RW2 of the second frequency band having a small second magnetic field signal strength such as an earthquake.
This is a circuit for extracting only the signal, and is configured by a band-pass filter or the like. On the output side of each of the electromagnetic wave extraction circuits 41 and 42, amplification circuits 43 and 44 for amplifying these output voltages and electromagnetic waves RW1 and RW from the output voltages of the amplification circuits 43 and 44 are provided.
2, direction detection circuits 45 and 46 for detecting the arrival directions are connected respectively.

Next, the operation of detecting the arrival direction of the electromagnetic waves RW1, RW2 will be described with reference to FIGS. When a first electromagnetic wave RW1 of a first frequency band (for example, 1 kHz to 300 kHz, or several kHz to several MHz) having a large first magnetic field signal strength comes from a horizontal direction due to a lightning strike or the like, the first antenna 10 The first and second antenna conductors 11 and 12 and the third antenna 20
And the fourth antenna conductors 21 and 22 have an induced voltage e
1 and e2 respectively occur. Due to the induced voltages e1 and e2 generated in the first antenna 10, the conductor diameter D1 is large,
From the first and second terminals 1 and 2 connected to the first antenna conductor 11 having a small number of turns N1 (for example, 7 to 10 times), an output voltage proportional to the arrival angle cos θ of the electromagnetic wave RW1 is generated. At this time, a voltage is also output from the first and third terminals 1 and 3, but the inductance of the second antenna conductor 12 is small because the conductor diameter D2 is small and the number of turns N2 (for example, 700 to 1000 times) is large. Since the impedance of the components and the like is large, the output voltages of the first and second terminals 1 and 2 are attenuated, and the voltages output from the first and third terminals 1 and 3 are very small.

Similarly, due to the induced voltages e1 and e2 generated in the second antenna 20, the third conductor D3 (for example, equal to the conductor diameter D1) is large and the number of turns N3 (for example, equal to N1) is small. From the fourth and fifth terminals 4 and 5 connected to the antenna conductor 21, an output voltage proportional to the arrival angle cos θ of the electromagnetic wave RW1 is generated. At this time, the fourth
And a voltage is also output from the sixth terminals 4 and 6,
Antenna conductor 22 has conductor diameter D4 (for example, conductor diameter D2
) And the number of turns N4 (e.g., equal to the number of turns N2) is large, so that the impedance such as the inductance component is large. Therefore, the output voltage of the fourth and fifth terminals 4 and 5 is attenuated, and the fourth and fifth terminals 4 and 5 are attenuated. The voltage output from the sixth terminals 4 and 6 is very small.

The output voltages of the first and second terminals 1 and 2 and the output voltages of the fourth and fifth terminals 4 and 5 are sent to an electromagnetic wave extraction circuit 41, where the magnetic field waveform is identified and Only one electromagnetic wave RW1 is extracted. At this time, the output voltages of the first and third terminals 1 and 3 and the output voltages of the fourth and sixth terminals 4 and 6 are sent to the electromagnetic wave extracting circuit 42, and the electromagnetic wave extracting circuit 42 Since this circuit extracts only the electromagnetic wave RW2, no voltage is output from this circuit 42. The first electromagnetic wave RW extracted by the electromagnetic wave extraction circuit 41
1 is, after being amplified by the amplifier circuit 43, the direction detection circuit 45
Sent to In the direction detection circuit 45, the arrival angle θ of the electromagnetic wave RW1 is calculated from the output voltages of the first and second terminals 1 and 2 and the output voltages of the fourth and fifth terminals 4 and 5.
Ask for. Thereby, the arrival direction of the electromagnetic wave RW1 having a large first magnetic field signal intensity due to a lightning strike or the like can be accurately detected.

On the other hand, a second frequency band (for example, 0.1 kHz) having a small second magnetic field signal strength due to an earthquake or the like.
When the second electromagnetic wave RW2 (about 10 KHz) arrives from the horizontal direction, the first and second antenna conductors 11 and 12 of the first antenna 10 and the third and fourth antenna conductors of the second antenna 20 Induced voltages e1 and e
2 occurs. The induced voltages e1 and e2 generated in the first antenna 10 cause the first and third terminals 1 and 3 connected to the first and second antenna conductors 11 and 12 having a large number of turns (N1 + N2) to generate the number of turns. , A relatively large voltage is output. At this time, a voltage is also output from the first and second terminals 1 and 2, but since the number of turns N1 of the first antenna conductor 11 connected thereto is small, the first and second terminals are not.
A relatively small voltage is output from the terminals 1 and 2.

Similarly, the induced voltages e1 and e2 generated in the second antenna 20 cause the fourth and fourth antenna conductors 21 and 22 having a large number of turns (N3 + N4) to be connected to the fourth and fourth antenna conductors 21 and 22, respectively.
And a relatively large voltage proportional to the number of turns is output from the sixth terminals 4 and 6. At this time, a voltage is also output from the fourth and fifth terminals 4 and 5, but since the number of turns N3 of the third antenna conductor 23 connected thereto is small, the fourth
A relatively small voltage is output from the fifth terminals 4 and 5. The output voltages of the first and third terminals 1 and 3 are sent to the electromagnetic wave extracting circuit 42, where the magnetic field waveform of the second electromagnetic wave RW2 is identified, and only the electromagnetic wave RW2 is extracted.
The output voltages of the first and second terminals 1 and 2 and the output voltages of the fourth and fifth terminals 4 and 5 are sent to an electromagnetic wave extraction circuit 41, which extracts only the first electromagnetic wave RW1. Since the circuit is an extraction circuit, no voltage is output from this circuit 41. The second electromagnetic wave R extracted by the electromagnetic wave extraction circuit 42
W2 is amplified by the amplification circuit 44 and sent to the direction detection circuit 46, where the arrival angle θ of the electromagnetic wave RW2 is calculated by calculation. Thereby, the second electromagnetic wave RW
2 can be detected with high accuracy.

As described above, in the first embodiment,
There are the following advantages (1) and (2). (1) Since the second and fifth terminals 2 and 5 are drawn out from the middle between the first and second antennas 10 and 20, the first and second terminals 2 and 5 of the first frequency band having a large first magnetic field signal strength such as lightning strike are obtained. For the first electromagnetic wave RW1, the first and second terminals 1,
2 and the output voltages of the fourth and fifth terminals 4 and 5,
The direction of arrival of the first electromagnetic wave RW1 is detected, and the first and third terminals 1 and 3 are provided for a second electromagnetic wave RW2 in a second frequency band having a small second magnetic field signal strength such as an earthquake.
3 and the output voltages of the fourth and sixth terminals 4 and 6,
The arrival direction of the second electromagnetic wave RW2 can be detected. As a result, the electromagnetic waves RW1 and RW2 over a wide frequency band can be received accurately and reliably with high sensitivity. Therefore, the present invention can be applied to the improvement of the reliability of electromagnetic wave reception and various uses using the reception result.

(2) The number of turns N1, N2, N of the first, second, third and fourth antenna conductors 11, 12, 21, 22
3, N4 and conductor diameters D1, D2, D3, D4
(= N3) <N2 (= N4) and D1 (= D3)> D2
(= D4), the electromagnetic waves RW1, RW
2, the conductor diameters of the first and second antennas 10 and 20 can be made thinner, whereby the weight and size of the entire loop antenna can be reduced.
In addition, by appropriately setting the conductor diameters N1, N2, N3, N4, etc., the reception frequency bandwidth of the loop antenna can be arbitrarily set.

Second Embodiment FIG. 4 is a schematic configuration diagram of a loop antenna according to a second embodiment of the present invention. Elements common to the elements in FIG. 1 according to the first embodiment are shown in FIG. Common symbols are assigned. In this loop antenna, the first and second antennas 1 of FIG.
In addition to the antennas 0 and 20, a third antenna 30 is provided which is horizontal to the ground and orthogonal to the first and second antennas 10 and 20. The third antenna 30 has an antenna conductor that is connected to the seventh terminal 7 at one end and connected to the eighth terminal 8 at the other end, and wound in the horizontal direction with respect to the ground. In this antenna conductor, when a third electromagnetic wave RW3 of a third frequency band having a third magnetic field signal intensity generated vertically from the ground and arriving, such as a direct earthquake, arrives, the third electromagnetic wave RW3 The third that occurs
Is output from the seventh and eighth terminals 7 and 8. The seventh and eighth terminals 7 and 8 are connected to an electromagnetic wave extraction circuit, an amplification circuit and a direction detection circuit as shown in FIG.

In the loop antenna according to the second embodiment, when the electromagnetic waves RW1, RW2 arrive from the horizontal direction,
As in the first embodiment, the first and second antennas 1
By using 0 and 20, the arrival directions of the electromagnetic waves RW1 and RW2 can be accurately detected. Further, when a third electromagnetic wave RW3 generated in the vertical direction from the ground arrives, such as a direct type earthquake, an induced voltage is generated in the third antenna 30,
The output voltage proportional to the arrival angle θ of the electromagnetic wave RW3 is the seventh
And at the eighth terminals 7 and 8. From this output voltage, a third electromagnetic wave R is output by an electromagnetic wave extraction circuit as shown in FIG.
After extracting only W3, the signal is amplified by an amplifier circuit, and the direction of arrival of the electromagnetic wave RW3 is calculated by a direction detection circuit, whereby the direction of arrival of the electromagnetic wave RW3 can be accurately detected. As described above, the second embodiment has substantially the same advantages as the first embodiment, and also has the following advantages (i) to (iii).

(I) Since the third antenna 30 in the horizontal direction is provided, the arrival direction of the third electromagnetic wave RW3 generated vertically from the ground, such as a direct earthquake, can be detected with high accuracy. (Ii) If the intermediate terminal is pulled out from the middle of the antenna conductor forming the third antenna 30, the electromagnetic wave RW3 in the frequency band corresponding to the magnitude of the arriving magnetic field signal strength is received,
The arrival direction of the electromagnetic wave RW3 can be detected with higher accuracy. (iii) An intermediate terminal is pulled out from the middle of the antenna conductor constituting the third antenna 30, and the conductor diameter and the number of turns of the antenna conductor from the seventh terminal 7 to the intermediate terminal, and from the intermediate terminal to the eighth terminal 8 If the conductor diameter and the number of turns of the antenna conductor are set to different values, the electromagnetic wave RW3 arriving from the vertical direction can be received with high sensitivity, and the conductor diameter of the third antenna 30 can be made smaller, whereby the entire loop antenna can be made. Can be reduced in weight and size.

Third Embodiment FIG. 5 is a schematic configuration diagram of an electromagnetic wave source position locating system showing a third embodiment of the present invention using the loop antenna of FIG. 1 or FIG. This electromagnetic wave source position locating system has a plurality of direction finding stations 100-1, 100-2,... Installed over a wide area to detect the direction of generation of the electromagnetic wave source RWS such as a lightning strike or an earthquake. doing.
The plurality of direction finding stations 100-1, 100-2,... Are connected to the position analysis device 110 via the respective transmission paths 105-1, 105-2,. Is connected.

Each direction detecting station 100-1, 100-2,...
Figure 1 or Figure 4 in east-west and north-south directions
The antenna has a loop antenna 101 for detecting a magnetic field component and a flat electrostatic field antenna 102 for detecting an electric field component, and a direction detector 103 is connected to an output side thereof. The direction detector 103 has a receiving side circuit as shown in FIG. 3, receives signals output from the loop antenna 101 and the electrostatic field antenna 102, identifies the type of the electromagnetic wave generation source RWS, and This is a circuit for calculating the direction and polarity of RWS, the current peak value, and the like, and is configured by a microcomputer or the like. The direction detector 103 is connected to a modem 104 for modulating and demodulating a transmission / reception signal.

The position analyzing device 110 is provided for each direction detecting station 10.
Have a plurality of modems 111, 112,... For performing modulation and demodulation of transmission / reception signals with respect to 0-1, 100-2, and so on, and a position analyzer 113 is connected to these modems 111, 112,. The position analyzer 113 detects the direction of the
Are circuits that locate the position and the like of the electromagnetic wave generation source RWS based on signals sent from 1, 100-2,..., And are configured by a microcomputer or the like. The display / storage device 120 is connected to the position analyzer 113.
The display / storage device 120 includes, for example, a personal computer (hereinafter, “personal computer”) connected to the position analyzer 113.
A CRT display 121, a printer 122, a floppy disk 123, a fixed desk 124, and the like are connected to the personal computer 121.

Next, the operation of the electromagnetic wave source location system of FIG. 5 will be described. Electromagnetic wave source RW such as lightning and earthquake
When an electromagnetic field is generated from S, the direction detecting station
At 0-1, 100-2,..., The magnetic field component of the generated electromagnetic field is detected by the loop antenna 101, and the electric field component is detected by the electrostatic field antenna 102. The direction detector 103 receives the output signals of the loop antenna 101 and the electrostatic field antenna 102, identifies the type of the generated electromagnetic field, and obtains the direction and polarity of the electromagnetic field generation source RWS, the current peak value, and the like. The output signal of each direction detector 103 is transmitted to each modem 104 and transmission paths 105-1, 105-
The modems 111, 1 of the position analysis device 110 via 2,.
, And so on.

The position analyzer 113 in the position analyzer 110
Then, at least two direction finding stations 100-1, 10
The position of the electromagnetic field generation source RWS is calculated by the resection method using the azimuth angle of the electromagnetic wave generation source RWS detected at the same time in 0-2. The position of the electromagnetic field generating source RWS calculated by the position analyzer 113 is displayed on a CRT display 121 by a personal computer 121 in a display / storage device 120, printed on a printer 122, or stored on a floppy disk 123 or a fixed disk. It can be stored on the desk 124.

As described above, in the third embodiment,
In the plurality of direction finding stations 100-1, 100-2,..., The magnetic field component of the electromagnetic field generated from the electromagnetic wave source RWS is detected by the loop antenna 101, and the electric field component is detected by the electrostatic field antenna 102; From these detection signals,
The type of the electromagnetic wave generation source RWS is identified by the direction detector 103, the azimuth and polarity of the electromagnetic wave generation source RWS, the current peak value, and the like are obtained.
., 105-2,... To the position analyzer 110, and the position analyzer 113 calculates the position of the electromagnetic wave source RWS in real time by the resection method. Therefore, an electromagnetic wave generated from the electromagnetic wave generation source RWS can be accurately detected over a wide range.

It should be noted that the present invention is not limited to the above embodiment, and various modifications are possible. For example, various modifications are possible, such as changing the receiving side circuit of FIG. 3 to another circuit configuration, or changing the system of FIG. 5 to another circuit configuration.

[0035]

As described in detail above, according to the first and second aspects of the present invention, the first orthogonal
From the second antenna and the second antenna
Terminal and the fifth terminal are drawn out, so that the electromagnetic waves corresponding to the magnitude of the magnetic field signal intensity arriving from the horizontal direction can be changed from those with a large magnetic field signal strength such as lightning strikes and high frequencies to those of an earthquake or the like. As described above, it is possible to accurately, reliably, and sensitively detect a signal having a low magnetic field signal intensity and a low frequency over a wide range. Moreover, by appropriately setting the number of turns and the conductor diameter of the antenna conductors constituting the first and second antennas, the detectable frequency bandwidth can be set arbitrarily, and the electromagnetic wave detection sensitivity can be improved, and the entire loop antenna can be improved. It is also possible to reduce the weight and size.

According to the third to fifth aspects of the present invention, since the third antenna is provided in the horizontal direction with respect to the ground and orthogonal to the first and second antennas, the third antenna can be used as in the case of a direct earthquake. Therefore, the electromagnetic wave generated in the vertical direction from the ground can be detected accurately, reliably and with high sensitivity. According to the invention according to claim 6, since the position of the electromagnetic wave generation source detected at the same time by at least two of the plurality of loop antennas is located, the electromagnetic wave generation is performed over a wide range. The position of the source and the like can be accurately measured.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a loop antenna according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating the principle of azimuth measurement using the loop antenna of FIG. 1;

FIG. 3 is a configuration diagram of a receiving-side circuit connected to the loop antenna of FIG. 1;

FIG. 4 is a configuration diagram of a loop antenna according to a second embodiment of the present invention.

FIG. 5 is a configuration diagram of an electromagnetic wave source position locating system showing a third embodiment of the present invention using the loop antenna of FIG. 1 or FIG. 4;

[Explanation of symbols]

1-8 First to eighth terminals 10, 20, 30 First, second, third antennas 11, 12, 13, 14 First, second, third,
Fourth antenna conductors 41, 42 Electromagnetic wave extraction circuit 43, 44 Amplification circuit 45, 46 Direction detection circuit 100-1, 100-2 Direction detection station 101 Loop antenna 102 Electrostatic field antenna 103 Direction detector 104, 111, 112 Modem 110 Position analysis device 113 Position analyzer 120 Display / storage device

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI G01W 1/16 G01W 1/16 E H01Q 7/00 H01Q 7/00 21/24 21/24

Claims (6)

[Claims] 1. A loop antenna in which a loop-shaped first antenna and a loop-shaped second antenna orthogonal thereto are installed in a direction perpendicular to the ground, wherein the first antenna has one end. The other end is connected to the first terminal, and the other end is connected to the second terminal. The first terminal is wound in the vertical direction with respect to the ground, and the first electromagnetic wave of the first frequency band having the first magnetic field signal strength is applied in the horizontal direction. From the first electromagnetic wave, a first induced voltage generated by the first electromagnetic wave is output from the first and second terminals, a first antenna conductor, one end is connected to the second terminal, and the other end is connected to the second antenna terminal. 3 and respectively wound around the first antenna conductor.
When a second electromagnetic wave of a second frequency band having a second magnetic field signal intensity different from the first electromagnetic wave arrives from the horizontal direction, a second induced voltage generated by the second electromagnetic wave is generated by the first electromagnetic wave. Terminal and a second terminal output from the third terminal.
The second antenna has one end connected to a fourth terminal and the other end connected to a fifth terminal, and is wound in a direction perpendicular to the ground. When an electromagnetic wave arrives from a horizontal direction, a third induced voltage generated by the first electromagnetic wave is output from the fourth and fifth terminals, a third antenna conductor, and one end is connected to the fifth terminal. The other end is connected to each of the sixth terminals and wound along the third antenna conductor,
When the second electromagnetic wave arrives from the horizontal direction, a fourth induced voltage generated by the second electromagnetic wave is constituted by the fourth terminal and a fourth antenna conductor output from the sixth terminal. A loop antenna, characterized in that: 2. The loop antenna according to claim 1, wherein the number of turns Na and the conductor diameter Da of the first and third antenna conductors and the number of turns Nb and the conductor diameter Db of the second and fourth antenna conductors are: , Na <Nb and Da> Db. 3. The antenna according to claim 1, further comprising a first antenna, a second antenna, and a third antenna that is horizontal to the ground and orthogonal to the first and second antennas. The third antenna has an antenna conductor which is connected to the seventh terminal at one end and connected to the eighth terminal at the other end and wound in the horizontal direction with respect to the ground, and has a third magnetic field signal strength. When a third electromagnetic wave of a third frequency band having a vertical direction arrives from the vertical direction, a third induced voltage generated by the third electromagnetic wave is generated by the seventh and eighth electromagnetic waves.
Characterized in that the loop antenna is configured to output from a terminal of the loop antenna. 4. The loop antenna according to claim 3, wherein an intermediate terminal is drawn out from an intermediate portion of the antenna conductor forming the third antenna. 5. The loop antenna according to claim 4, wherein a conductor diameter of the antenna conductor from the seventh terminal to the intermediate terminal and a conductor diameter of the antenna conductor from the intermediate terminal to the eighth terminal. And a different value. 6. A plurality of first antennas of the loop antenna according to claim 1 are installed on the ground in a north-south direction, and the plurality of loop antennas serve as sources of electromagnetic waves. An electromagnetic wave source position locating system, comprising: detecting an azimuth and locating the position of the electromagnetic wave source detected at the same time by at least two loop antennas among the plurality of loop antennas.