JPH07307608A - Antenna system - Google Patents

Abstract

PURPOSE:To turn an antenna main body in a direction where reception sensitivity is high at all times regardless of the direction and posture of a mobile object in an antenna device mounted to the mobile object such as a vessel and a vehicle, etc. CONSTITUTION:A movable part A is supported by a shaft 2 and the shaft 4 to a supporting body C integrated with a base B and the center axis O is made vertical at all times by the gravity of a weight 6. Thus, regardless of the posture of the mobile object D such as the vessel or the like, the antenna main body 1 becomes parallel to a horizontal surface at all times. Also, by a mechanism and a circuit inside an antenna supporting mechanism 7, the antenna main body 1 is rotated with the center axis O as a center and the antenna main body 1 is turned to the direction where the reception sensitivity is high at all times. Thus, the antenna main body 1 is turned to the direction optimum for receiving broadcasting radio waves at all times.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna device for supporting an antenna body having a different receiving sensitivity depending on the orientation, such as a planar antenna for receiving BS broadcasts. As described above, the present invention relates to an antenna device in which the attitude of the antenna device with respect to the horizontal plane is always stable even if the attitude of the support body changes.

[0002]

2. Description of the Related Art FIG. 5 shows a flat antenna body 1 for receiving a BS broadcast mounted on an automobile or the like. The antenna body 1 is provided with a plurality of receiving elements arranged therein. The antenna body 1 of this type has directivity in reception sensitivity, and the direction S with high reception sensitivity has a predetermined elevation angle θ with respect to a line (plane) H having a constant azimuth F and parallel to the horizontal plane. In the case of BS broadcast reception, the direction in which radio waves are sent from the satellite is 36 degrees in the southwest direction in the Kanto region and 44 degrees in the northeast direction in Shikoku and Kyushu regions.
Therefore, it is preferable that the antenna body 1 is installed so that the direction S in which the receiving sensitivity of the antenna body 1 is high matches the direction in which the radio wave is sent, depending on the region where the antenna body 1 is used.

[0003]

However, for example, when the antenna main body 1 is mounted on a ship or a vehicle, even if the direction S with high reception sensitivity is set to the 36 degrees or 44 degrees, When the vehicle is swaying and largely tilted with respect to the horizon, or when the vehicle is traveling on a sloping ground such as a mountain area, the elevation angle θ (angle with respect to the horizontal plane) of the antenna body 1 in the direction S with high reception sensitivity is substantially However, there is a problem that the reception sensitivity is lowered. Further, when the antenna main body 1 is mounted on a ship or a vehicle, the azimuth F of the direction S with high reception sensitivity changes at any time depending on the traveling direction of the ship or vehicle, which causes the reception sensitivity to constantly fluctuate.

The present invention is to solve the above-mentioned conventional problems, and even if the antenna is mounted on, for example, a ship or a vehicle, and the tilt angle of the support changes, the radio wave is transmitted in the direction in which the receiving sensitivity of the antenna is high. Being able to always adjust to the elevation angle being sent, and to be able to always adjust the direction with high antenna reception sensitivity to the direction in which radio waves are being sent, even if the traveling direction of the ship or vehicle changes. It is an object of the present invention to provide an antenna device capable of preventing a decrease in reception sensitivity.

[0005]

SUMMARY OF THE INVENTION An antenna device according to the present invention comprises an antenna body having different receiving sensitivities depending on the orientation, a movable part on which the antenna body is installed, a support for supporting the movable part, and a movable body for the support. A weight provided on the movable portion below the supporting portion of the portion, and the movable portion is supported by the support so that the weight is always in the same posture with respect to the horizontal plane due to the gravity of the weight. It is a feature.

It is meant that the movable portion is supported so as to always have the same posture with respect to the horizontal plane so that the reference plane of the movable portion (for example, the installation surface of the antenna body) is always parallel to the horizontal plane (or the horizontal plane). Supported so that they always have the same tilt angle with respect to
An intermediate member that is rotatably provided on the support body by the shaft is provided, and a movable portion is provided on the intermediate member by a second shaft that is orthogonal to the first shaft in the same plane as the first shaft. It can be realized by a structure that is supported so as to be rotatable.

In addition, a table which can be rotated together with the antenna main body with respect to a vertical axis in the movable portion, a drive source for rotating the table, and the drive source which is controlled according to the receiving sensitivity of the antenna main body. And a control circuit unit for setting the amount of rotation.

Further, it is preferable that a flexible cover is provided between the base to which the support is fixed and the movable portion so as to surround a portion where the support supports the movable portion.

[0009]

In the above first means, even if the supporting member is installed on a ship or a vehicle, the movable portion is moved by the weight of the weight even when the supporting member is changed in angle with respect to the horizontal plane. The posture is always the same with respect to the horizontal plane. Therefore, the elevation angle with high reception sensitivity of the antenna body installed in the movable part can be always matched with the elevation angle at which the radio wave is transmitted. Therefore, even if the ship tilts due to waves or the vehicle travels on a slope, the reception sensitivity does not decrease.

In the second means, a table that rotates about a vertical axis is further provided on the movable portion, and the table can rotate together with the antenna body. This table drives a stepping motor or the like. It is designed to be rotated by the source. The control circuit section is provided with a C / N detection section for the antenna reception output, a main control section such as a microcomputer, and a stepping motor control section. The main control section controls the radio wave reception sensitivity of the antenna body. The drive source is controlled so that the rotation amount of the table is always set. Therefore, the direction in which the receiving sensitivity of the antenna body is high is always adjusted to the direction in which the radio wave is sent.

By the first means, the movable portion is always kept in a stable posture with respect to the horizontal plane, and further, the antenna body is rotated in accordance with the direction in which the radio wave is sent by the rotation control of the table. The antenna body can always be set in a direction with high reception sensitivity regardless of the inclination of the ship or vehicle in any direction, and the reception sensitivity is stable.

In the third means, the supporting portion of the movable portion with respect to the support is surrounded by the flexible cover. Therefore, even when this antenna device is mounted on a ship, it is possible to prevent the supporting portion from being protected by the flexible cover and being corroded by the tide to make the operation awkward. Further, since the cover attached to the movable part is flexible, the cover does not hinder the operation of the movable part.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing an overall structure of an antenna device according to the present invention, FIG. 2 is a perspective view showing an example of a supporting structure of a movable portion by a support, and FIG. 3 is an enlarged sectional view showing an antenna supporting mechanism provided in the movable portion. 4 and 5 are circuit block diagrams showing the circuit mechanism portion of the antenna device. The antenna main body 1 shown in FIG. 1 is the same planar-shaped antenna for BS broadcast reception as shown in FIG. 5, and is provided with a plurality of receiving elements arranged. The antenna body 1 has directional reception sensitivity, and the direction S with high reception sensitivity has a predetermined elevation angle θ with respect to a line (plane) H parallel to the horizontal plane, and the direction S with high reception sensitivity has a predetermined azimuth F. Is directed to.

A base B is fixed to a moving body D such as a ship or a vehicle. A plate-shaped support C is fixed to the base B with a gap or is integrally formed. The first shafts 2 and 2 are fixed to each of the supports C on the same axis. As shown in FIG. 2, the ring-shaped intermediate member 3 is rotatably supported by the first shafts 2 and 2.
The second shafts 4 and 4 are arranged and fixed on the inner peripheral surface of the intermediate member 3 on the same axis. The second shafts 4 and 4 are oriented in the same plane as the first shafts 2 and 2 and are oriented orthogonal to the first shafts 2 and 2. The movable part A has the second shafts 4, 4
It is rotatably supported with respect to.

As shown in FIG. 2, the central axis (vertical axis) O passing through the center of the movable portion A is α with the first axes 2 and 2 as fulcrums.
It can be tilted in the direction, and can be tilted in the β direction with the second shafts 4 and 4 as fulcrums. As a result, the central axis (vertical line) O can be tilted in all directions, and the installation surface E serving as the installation reference of the antenna body 1 in the movable part A can be tilted in all angular directions with respect to the base B. You can do it. The movable portion A has a movable case 5 whose lower part has a spherical shape, and a weight 6 is fixed inside the lower vertex of this spherical shape. The center of gravity of the weight 6 is arranged on the central axis O of the movable portion A. Due to the gravity of the weight 6, the central axis O can always be oriented in the vertical direction regardless of the posture of the moving body D. Further, the installation surface E has a central axis O
Since it is a plane orthogonal to, the installation plane E can always be positioned parallel to the horizontal plane.

An antenna support mechanism 7 is fixed to the installation surface E, and the antenna main body 1 is attached to the antenna support mechanism 7.
Is installed. FIG. 3 shows the internal structure of the antenna support mechanism 7. A support plate 10 parallel to the installation surface E is provided in the antenna support mechanism 7. Support plate 10
Bearings 12, 12 supported by bearing holders 11, 11.
Is provided, and the hollow shaft 13 is rotatably supported by the bearings 12, 12. The center line of the hollow shaft 13 coincides with the central axis O, and the hollow shaft 13 is integrally provided at the rotation center of the large diameter gear 14. A table 16 is fixed to the upper surface of the large diameter gear 14 via a spacer 15. The upper surface 16a of the table 16 is parallel to the installation surface E, and the antenna body 1 is fixed to the upper surface 16a. A stepping motor M as a rotary drive source is fixed to the support plate 10. A pinion 17 is fixed to the output shaft of the stepping motor M, and the rotational force of the pinion 17 is transmitted to the large diameter gear 14 via an intermediate gear 18 and a drive gear 19. The rotary power of the stepping motor M causes the table 16 and the antenna body 1 to rotate about the central axis O.

A top case 8 is fixed on the spherical movable case 5. The upper portion of the top case 8 is a flat plate, and is arranged at a predetermined distance δ from the upper surface of the antenna body 1. This top case 8 and base B
A cylindrical flexible cover 9 is connected between and.
The flexible cover 9 is formed in a bellows shape from rubber or another material, and the flexible cover 9 allows the movable case 5 and the first shaft 2 and the second shaft supporting the movable case 5. The support mechanism (support point) by 4 is sealed. Therefore, when the antenna device is mounted on, for example, a ship, it is possible to prevent the rotation mechanism portion (supporting portion) by the shafts 2, 4 and the intermediate member 3 from being corroded by the tide.

Further, in the embodiment of FIG. 1, the antenna body 1, the antenna support mechanism 7 and the circuit mechanism portion 30 therein are provided.
All are sealed inside the movable case 5 and the top case 8. Therefore, even when the flexible cover 9 is not provided, the above-mentioned members are sealed and protected from the outside. Further, in the embodiment of FIG. 1, the top case 8 covering the upper surface of the antenna body 1 is fixed to the movable portion A, and the top case 8 and the antenna body 1 move together without changing their mutual positional relationship. ing. However, as another structure, the top case 8 is fixed to the base B so as not to move, and under the top case 8,
The antenna body 1 may be provided in a movable portion and supported in a movable state with its central axis always facing the vertical direction. However, the distance δ between the top case 8 and the antenna body 1
Is a factor that affects the receiving sensitivity, so that the top case 8 is provided in the movable portion A as shown in FIG. 1 so that the distance δ between the top case 8 and the antenna body 1 is always constant. Is preferred.

A low noise booster 21 is fixed to the lower surface of the table 16 and is connected to the antenna body 1. The low noise booster 21 is provided at the rotation center position of the table 16, and the antenna input signal from the low noise booster 21 is taken out by the flexible cable 22. The flexible cable 22 passes through the hollow shaft 13,
It is guided into the circuit mechanism portion 30 located below the support plate 10.

FIG. 4 is a block diagram showing the structure of the circuit mechanism section 30. The antenna input signal from the low noise booster 21 is sent to the FM via the flexible cable 22.
It is sent to the demodulation unit 31 and demodulated. The demodulated FM signal is sent to the C / N detector 32, and the carrier signal-to-noise ratio (C / N
(N ratio) is detected and sent to the main controller 33 such as a microcomputer. In the main controller 33, the C / N detector 3
The motor control unit 34 is controlled based on the carrier signal-to-noise ratio detected in 2, and the motor control unit 34 drives the stepping motor M. That is, the main controller 3
When it is determined in 3 that the C / N ratio of the received signal from the antenna main body 1 is below a certain level, a drive command is issued to the stepping motor M, and the large diameter gear 14, the table 16 and the antenna main body 1 are sent. Is driven to rotate. Then, when the C / N ratio of the received signal from the antenna body 1 exceeds a certain level, the stepping motor M is stopped. As a result, even if the traveling direction of the moving body D changes, the direction S with high reception sensitivity of the antenna body 1 is always directed in the direction in which radio waves are sent.

The table 16 and the antenna body 1
When is rotated on the support plate 10, the flexible cable 22 extending from the low noise booster 21 is twisted. Therefore, when the table 16 is rotated by the stepping motor M by a predetermined angle or more than the number of rotations, when the table 16 is rotated next time, the stepping motor M is reversely rotated and the table 16 is rotated in the opposite direction. It is preferable to control the antenna main body 1 so that the antenna main body 1 is directed to a direction having high reception sensitivity by rotating the antenna. As a result, it is possible to prevent the flexible cable 22 from being twisted in many directions in the same direction, and to prevent disconnection.

The F demodulated by the FM demodulation unit 31
The M signal is given to the input switching unit 37 via the video signal processing unit 35 and the still image switching unit 36. Still image switching unit 36
Is for stopping the image when the C / N detector 32 detects that the noise ratio is high. The demodulated FM signal is processed by the audio signal processing unit 38 and the audio noise reduction unit 39 and sent to the input switching unit 37. Video output and audio output from the input switching section 37 are given to the television monitor 40 from respective output terminals. The output line 41 from the circuit mechanism unit 30 is, as shown in FIG.
A flexible cable having a bending margin 41 a extends outside the flexible cover 9.

As shown in FIG. 5, in the antenna body 1 mounted on this antenna device, the direction S with high reception sensitivity is the predetermined elevation angle θ and the predetermined azimuth F. In the movable part A in which the antenna body 1 is mounted, the antenna body 1 is oriented orthogonal to the central axis O, and the movable body D in which the antenna device is mounted is in any posture. The center axis O is always oriented in the vertical direction due to the gravity of the weight 6 provided on the center axis O below the supporting point of the shafts 2 and 4. Therefore, moving objects such as ships and vehicles D
The antenna body 1 is always maintained in a posture parallel to the horizontal plane even if is tilted due to waves or sloping ground. Therefore, the direction S with high reception sensitivity shown in FIG. 5 is always directed to the direction of the predetermined elevation angle θ. In addition, the C / N detector 3 shown in FIG.
2, the rotation angle of the stepping motor M is controlled by the control circuit unit including the main control unit 33, the motor control unit 34, etc., and the rotation position of the large diameter gear 14 is controlled by this, so that the receiving sensitivity of the antenna main body 1 is controlled. The high azimuth F is always directed in the direction in which radio waves are sent. Therefore, regardless of the tilted posture and the direction of the moving body D, the direction S with high reception sensitivity of the antenna body 1 is always directed to the direction and elevation angle in which radio waves are transmitted.

The mechanism for rotating the antenna body 1 is not limited to the gear mechanism shown in FIG. 3, but may be a mechanism using a toothed belt. Depending on the structure and type of the antenna, if the antenna body does not have directivity in the installation direction as long as it is installed in a posture parallel to the horizontal plane, use the large-diameter gear 14 or the like shown in FIG. The rotating mechanism of the antenna main body 1 is unnecessary, and the antenna main body and the movable portion are supported by the support structure in which the central axis O is always oriented vertically by using the first and second shafts and the intermediate member. It is possible to obtain the effect of increasing the reception sensitivity only by the above. Also, the antenna body 1 is not limited to BS reception,
For example, it may be one that receives radio waves from GPS satellites for a navigation system.

[0025]

According to the first aspect of the present invention, even when the angular posture of the support body is constantly changed, such as when the antenna body is mounted on a ship or a vehicle, the antenna body is always placed on the horizontal plane. It is possible to maintain a stable posture, and it is possible to prevent a decrease in reception sensitivity due to a change in the angle posture of the antenna device.

According to the second aspect of the present invention, in addition to maintaining the posture with respect to the horizontal plane, the antenna body is rotated together with the table in accordance with the receiving sensitivity of the antenna body so that the antenna body is always directed in the direction of high receiving sensitivity. Even if the traveling direction of the ship or vehicle changes, it is possible to always receive with high sensitivity.

According to the third aspect of the invention, since the support portion of the movable portion of the support is surrounded by the flexible cover,
The supporting part of the movable part can be protected from the tide, etc., and it becomes possible to prevent malfunction due to rust or the like.

[Brief description of drawings]

FIG. 1 is a sectional view showing the overall structure of an antenna device of the present invention,

FIG. 2 is a perspective view showing a support structure of a movable part,

FIG. 3 is a side view showing a mechanism for rotating the antenna body in the antenna support mechanism,

FIG. 4 is a circuit block diagram showing a structure of a circuit mechanism unit,

FIG. 5 is a perspective view showing a planar antenna,

[Explanation of symbols]

 1 Antenna Main Body 2 First Axis 3 Intermediate Member 4 Second Axis 5 Movable Case 6 Weight 7 Antenna Support Mechanism 8 Top Case 9 Flexible Cover 10 Support Plate 12 Bearing 13 Hollow Shaft 16 Table 21 Low Noise Booster 22 Flexible Cable 30 circuit mechanism section 31 FM demodulation section 32 C / N detection section 33 main control section 34 motor control section A movable section B base C support E installation surface M stepping motor

Claims (3)

[Claims] 1. An antenna main body having different reception sensitivity depending on the orientation, a movable part on which the antenna main body is installed, a support for supporting the movable part, and a movable part below the supporting part of the movable part by the support. An antenna device, comprising: a weight provided in a portion, and the movable portion is supported by the support body so that the movable portion always has the same posture with respect to a horizontal plane due to gravity of the weight. 2. The movable part has a table that can rotate with respect to a vertical axis together with the antenna body, a drive source that rotates the table, and the drive source that controls the drive source according to the receiving sensitivity of the antenna body. The antenna device according to claim 1, further comprising a control circuit unit that sets a rotation amount. 3. The antenna device according to claim 1, wherein a flexible cover is provided between the movable part and the base to which the support is fixed, and the flexible cover surrounds a portion where the support supports the movable part.