1. An antenna device comprising: an antenna unit; a camera unit fixed so that its direction relative to the antenna unit doe5 s not change; and a direction adjustment control unit that adjust s a direction of the antenna unit, wherein the direction adjustment control unit controls to return the direction of the 10 antenna unit back to an initial direction based on an image taken by the camera unit.

2. The antenna device according to Claim 1, wherein when the antenna uni t is oriented in the initial direction, the antenna unit 15 is oriented in a direct ion in which it can perform good wireless communication with an opposite station, the camera unit captures an arbitrary object in an imaging area when the antenna unit is oriented in the initial direction, and the direction adjustment control unit adjusts the direction of the antenna 20 unit based on a direct ion in which the object is displaced in the imaging area.

3. The antenna device according to Claim 1 or 2, wherein the direction adjustment control unit has a function of automatically changing the direct ion of the antenna unit and updat ing the ini tial direction based 25 on an image taken by the camera unit and a radio wave strength received by the antenna unit .

4. A control method of an antenna device including an antenna unit mounted so that its direction is adjustable, a motor-driven unit that changes a 30 direction of the antenna unit , a camera uni t fixed so that its direction relative to the antenna unit does not change, and a direction adjustment control unit that supplies a drive signal to the motor -driven unit and adjusts the direction of the antenna unit , the method comprising: control ling to return the direction of the antenna unit back to an initial 18 direction based on an image taken by the camera unit.

DESCRIPTION
ANTENNA DEVICE AND CONTROL METHOD OF ANTENNA DEVICE
Technical Field
[0001]
The present invention relates to an antenna device and a control method o5 f
an antenna device that automatically adjust the direction of an antenna.
Background Art
[0002]
When installing a directional antenna, it is important to orient it toward an
10 appropriate direction in order to maximize the reception level. Since radio waves
at mil limeter-wave frequencies have been used recently, it is required to set the
antenna orientat ion with respect to the wave source antenna with a level of
accuracy equivalent to the accuracy needed to thread the eye of a needle. For
example, extremely fine angle adjustment of 1.0º or less, such as 0.4º or 0.2º, is
15 required today. Various methods for sett ing the antenna orientation (i.e.,
orientating the antenna) toward the wave source direction have been proposed (for
example, Patent Literature 1, 2 and 3).
Citation List
Patent Literature
20 [0003]
PTL1: Japanese Unexamined Patent Application Publication No.
2007-33380
PTL2: Japanese Unexamined Patent Application Publication No.
2007-88576
25 PTL3: Japanese Unexamined Patent Application Publication No.
2005-72780
Summary of Invention
Technical Problem
[0004]
30 In recent years, small cells with a coverage of about several tens to several
hundreds meters have been used for the purpose of increasing the communication
capacity, enhancing the communication speed and improving the coverage hole
mainly in city areas. Small cel ls are also called picoce lls and femtocells. When
installing a large number of antenna devices in a city area, it is necessary to install
3
an antenna device in a position near the ground or on a non -robust structure in
many cases, and, for example, there is a case where an antenna device is installed
on a lamp post .
However, a lamp post or the like is subject to deformation and mechanical
vibration due to external forces such as wind, vibrat ion from a subway and a5 n
earthquake. For example, in Fig. 14, the antenna 10 is mounted on a structure
(for example, a lamp post ). When a structure 40 vibrates, the antenna 10 vibrates
accordingly. Because the antenna 10 transmits and receives a directional beam
51, if the orientation of the antenna 10 (e.g. the directional beam 51) changes due
10 to a mechanism vibration, the communicat ion quality of a radio link is
significantly degraded.
Further, when the antenna 10 is mounted on a lamp post 50, even if the
vibration of the lamp post 50 is very small , the vibration of the antenna 10 that is
mounted at the upper part of the lamp post 50 is not necessarily small . Further, in
15 the case where the frequency of a mechanical vibration happens to be synchronous
with the natural frequency of the lamp post , there is a concern that the vibration of
the antenna 10 can be significantly large.
[0005]
Additionally, the fact that not only the antenna i tself but also a station
20 opposite to the antenna (hereafter, ‘an opposite station’) is subject to vibration
makes the problem more complicated.
If an opposite stat ion is stable and thus not moved, a decrease in reception
strength is attributed only to vibration of the antenna itself. In this case, it is
only necessary to search for a direct ion in which the reception strength is
25 maximized and adjust the direct ion so that it is oriented to that direction. (Such
an operation may be achieved by feedback control on the basis of the reception
strength.)
However, if an opposite station vibrates also, a decrease in reception
strength is not attributed only to vibration of the antenna itself. It is impossible
30 to search for a direction in which the reception strength is maximized in the
circumstances where both the antenna i tself and the opposite station are vibrating,
and their control operat ions collapse (diverge) in the worst case.
[0006]
An exemplary object of the present invention is to provide an antenna
4
device and a control method of an antenna device that can maintain the
communicat ion quality even when a mechanical vibrat ion occurs in a structure on
which an antenna device is mounted.
Solution to Problem
[00075 ]
An antenna device according to an exemplary aspect of the present
invention includes an antenna unit, a camera unit fixed so that its direction relative
to the antenna uni t does not change, and a direct ion adjustment control unit that
adjusts a direction of the antenna unit, wherein the direction adjustment control
10 unit controls to return the direction of the antenna unit back to an initial direction
based on an image taken by the camera unit.
[0008]
A control method of an antenna device according to an exemplary aspect
of the present invention is a control method of an antenna device including an
15 antenna unit mounted so that its direction is adjustable, a motor -driven uni t that
changes a direction of the antenna unit, a camera unit fixed so that its direction
relative to the antenna unit does not change, and a direction adjustment control
unit that supplies a drive signal to the motor -driven unit and adjusts the direction
of the antenna unit, the method including control ling to return the direction of the
20 antenna unit back to an initial direction based on an image taken by the camera
unit.
Advantageous Effects of Invention
[0009]
According to the exemplary aspects of the present invention, it is possible
25 to maintain the communication quality even when a mechanical vibration occurs in
a structure on which an antenna device is mounted.
Brief Description of Drawings
[0010]
Fig. 1 is a view showing the state where an antenna device according to a
30 first exemplary embodiment is set up.
Fig. 2 is a functional block diagram of a control unit.
Fig. 3 is a flowchart showing an operation procedure of automatically
adjusting the orientat ion of an antenna uni t in the most appropriate direction.
Fig. 4 is a view showing the antenna device viewed from above.
5
Fig. 5 is a view showing an example of a camera image at an ini tial
position.
Fig. 6A is a view showing the state where a lamp post is bent due to
vibration.
Fig. 6B is a view showing the state where a lamp post is bent due t5 o
vibration.
Fig. 7 is a view showing the state where a lamp post is skewed due to
vibration.
Fig. 8 is a view showing the state where the antenna device is displaced in
10 paral lel due to vibrat ion for reference.
Fig. 9 is a view showing the state where a lamp post is bent due to
vibration.
Fig. 10 is a view showing an example of a camera image.
Fig. 11 is a view illustrating a process of matching images.
15 Fig. 12 is a view illustrating a gap.
Fig. 13 is a view il lustrating a change of the orientation of the antenna unit
so as to cancel vibrat ion.
Fig. 14 is a view illustrating background art.
Description of Embodiments
20 [0011]
Exemplary embodiments of the present invention are illustrated in the
drawings and described hereinafter by ref erring to the reference symbols of
elements in the drawings.
(First exemplary embodiment)
25 A first exemplary embodiment of the invention is described hereinafter.
Fig. 1 is a view showing the state where an antenna device according to a
first exemplary embodiment is set up.
An antenna device 100 is mounted, for example, on a lamp post 50 (fixed
structure). When mounting the antenna device 100 on the lamp post 50, an
30 installat ion base 60 is first attached to the lamp post 50. The installat ion base 60
includes an L-shaped member 61 and a bracket 62. The lamp post 50 is placed
between the L-shaped member 61 and the bracket 62, and the L-shaped member 61
and the bracket 62 are fastened by a bolt 63 and a nut 64. The L-shaped member
61 serves as an instal lation plane.
6
[0012]
The antenna device 100 is fixed on the installation plane (L-shaped
member 61). The antenna device 100 includes an antenna uni t 110, a pan head
120, a camera 130, and a control unit 140.
[00135 ]
The antenna unit 110 is a parabolic antenna in this example. The antenna
unit is an antenna having directional ity, and it is not limited to being a parabolic
antenna, and it may be instead a planar antenna,
The pan head 120 includes a base table 121, a rotating table 122 that can
10 rotate at 360º in the horizontal direct ion (azimuth direction) wi th respect to the
base table 121, and a turning table 123 that can turn in the vertical direction
(elevation and depression directions) wi th respect to the rotating table 122.
The control unit 140 and the antenna unit 110 are held by the turning table
123 and their positions change in accordance with a change in the posi tion of the
15 turning table 123.
[0014]
Further, the pan head 120 includes a rotating motor 124 that drives the
rotating table 122 to rotate it and a turning motor 125 that drives the turning table
123 to turn.
20 [0015]
The camera 130 may be a so-called digital camera, for example, which
includes a lens and an image sensor (CCD or CMOS) and has a function of taking
images. A direction which the camera 130 takes images of is arbitrary. Note
that , however, as will be apparent from the following descript ion, an object whose
25 position is set (fixed) needs be within an imaging region. In other words, an
imaging direction to merely take a sky image, for example, is of no use. It is
preferred that a construct such as a building or a house, for example, appears in the
image. Further, if possible, it is more preferred that an object with a clear color,
shape or the l ike appears in the image. A wor ker who installs the antenna device
30 100 looks over the surroundings and roughly determines the orientation of the
camera 130 so that the above-described construct appears in the image. Then, the
worker fixedly mounts the camera 130 on an appropriate place on the antenna
device 100. For easier understanding, Fig. 1 shows the case where the
transmitting and receiving direction of the antenna unit 110 and the imaging
7
direction of the camera are shifted by about 90º. Specifically, the transmitting
and receiving direct ion of the antenna uni t 110 is rightward, and the imaging
direction of the camera is frontward.
[0016]
Although the camera 130 is mounted on the antenna unit 110 in Fig. 1, i5 t
may be fixed to the housing 141 of the control unit 140. The camera 130 may be
fixed to any place on the antenna device 100. Although the camera 130 may be
mounted on the antenna device 100 by any means, even when the easiest way of
mounting the camera 130 is employed, it is necessary that the positions and
10 orientations of the antenna unit 110 and the camera 130 are not displaced relative
to each other. Stated differently, if the position or orientation of the antenna unit
110 changes, the posi tion or orientat ion of the camera 130 should change in the
same way.
[0017]
15 The camera 130 and the antenna device 100 are not necessarily separated
from each other, and the camera 130 may be embedded in the antenna device 100.
In other words, the camera 130 may be built in the antenna device 100.
[0018]
The control unit 140 includes a housing 141 and an internal circuit.
20 Fig. 2 is a functional block diagram of the internal circuit. In Fig. 2, the
functions of the control uni t 140, except for a motor driver 220, may be
implemented as a result of a CPU loading a program.
[0019]
The control unit 140 includes a transmit ting and receiving unit 150 and a
25 direction adjustment control unit 200.
The transmitting and receiving unit 150 is an electrical circuit unit that
includes a receiving circuit 151 and a transmitting circuit 152 and performs
modulation and demodulation of signals according to the need.
The direction adjustment control unit 200 includes a central control unit
30 210, a motor driver 220, and an image processing unit 230.
The image processing unit 230 includes an image capture uni t 231, an
initial image recording unit 232, an image matching processing unit 233, and a
displacement calculat ion unit (position calculation unit) 234.
The detailed operation of each functional unit is described later with
8
reference to the flowchart and the illustrat ion.
[0020]
(Description of Operation)
A series of operations for automatical ly adjusting the orientation of the
antenna unit 110 in the most appropriate direction is described hereinafter 5 .
To implement the automatic orientation adjustment, the antenna device
100 needs to be set up appropriately as shown in Fig. 1. Specifically, i t is a
prerequisite that the antenna unit 110 is oriented in the direction of an opposite
station and it favorably transmits radio waves to the opposite station and receives
10 them therefrom when there is no vibration or the like. To orient the direction of
the antenna unit 110 toward the opposite station 20, an existing method may be
used, or a direction in which the reception strength level reaches its peak may be
searched for by trial and error.
[0021]
15 It is assumed that the antenna device 100 is set up appropriately.
The direction (azimuth, elevation) in which the antenna unit 110 is
oriented at this time is referred to as the "initial direction" of the antenna unit 110
or the "init ial position" of the antenna uni t 110.
If it is possible to control the antenna uni t 110 to always turn back to the
20 initial direct ion (initial position), it would be possible to maintain the high
communicat ion quality of a radio l ink.
The problem is how to return the antenna unit 110 back to the initial
direction (initial posi tion).
[0022]
25 Fig. 3 is a flowchart showing an operation procedure of automatically
adjusting the orientat ion of the antenna unit 110 in the most appropriate direction.
The first to be performed is the capture of an initial image (ST110). The
camera 130 is already mounted on the antenna device 100, and the image capture
unit 231 captures the current image in the camera 130 as an init ial image (ST110).
30 [0023]
Fig. 4 is a view showing the antenna device 100 viewed from above. In
Fig. 4, the imaging range of the camera 130 is indicated by the dotted line. (Note
that the alternate long and short dashed line indicates the center line of the
imaging range. ) In the example of Fig. 4, it is assumed that a building 30 stands
9
near the center of the imaging range of the camera 130. Accordingly, the
building 30 appears on the right of the center of the camera image as shown in Fig.
5. The initial image is recorded in the ini tial image recording unit 232.
[0024]
After capturing the initial image (ST110), the central control unit 215 0
performs position feedback control based on the camera image at a specified
control cycle in ST130 to ST170.
[0025]
To better understand the effects of this exemplary embodiment, assume the
10 case where a relatively large vibration is applied to the lamp post 50. When the
relatively large vibration is applied to the lamp post 50, the lamp post 50 is bent or
skewed. For example, i t i s assumed that a pole wi th a height of 10 m is bent and
the upper end is displaced by about 10 mm as shown in Fig. 6A. In this case, the
transmitting and receiving direction of the antenna unit is shifted by about 0.6º in
15 the EL direction (elevation angle, elevation and depression directions) even based
on simple linearization (Fig. 6A). In practice, the displacement of the direction
of the antenna unit is larger because the pole is bent at a multi -order curve (Fig.
6B).
[0026]
20 Further, as shown in Fig. 7, the pole is also skewed. In Fig. 7, the section
of the pole is a square, not a circle, for easier understanding the skew. According
to some experimental data, the upper end of the pole is skewed by about 3º, and in
this case, the transmi tting and receiving direction of the antenna unit is displaced
by about 3º to the AZ direction (azimuth angle).
25 [0027]
The communication quality is degraded if the pole is bent or skewed and
the transmitting and receiving direction of the antenna unit 110 is displaced by
about 0.6º or more, and it is thus necessary to take some measures.
[0028]
30 Note that , some may think that translational motion (parallel translation)
would occur in the antenna device when a relatively large vibration is applied to
the lamp post 50, and this is described in addition.
For example, it is assumed that the antenna device moves in paral lel by 10
mm in a lateral direct ion when it is at a distance of 100m from the opposite station
10
20 as shown in Fig. 8. The displacement of the direction in this case is about
0.06º, and therefore i ts effect on the communication quality is smaller than the
displacement of the direction due to bending or skewing described above.
[0029]
Further, it is assumed that if a relatively large vibration is applied to th5 e
lamp post 50, the lamp post 50 is skewed as shown in Fig. 9, and thereby the
orientation of the antenna device 100 is changed. (Note that, although the
position of the antenna device 100 is largely displaced in Fig. 9 for the
convenience of description, it is an exaggeration). The camera 130 is displaced
10 together with the antenna device 100. Accordingly, an image taken by the camera
130 changes. As a result , the building 30 is displaced leftward in the imaging
region as shown in Fig. 10.
[0030]
The image capture unit 231 captures the current image taken by the camera
15 130 (ST130). Then, the image processing unit 230 compares the current image
with the init ial image and thereby calculates a gap between the current image and
the initial image (ST140). Comparing two images and recognizing the images to
see how much one is deviated from the other is an application of pattern matching
and implemented by various methods. For example, Phase -Only Correlation is
20 known.
[0031]
The image matching processing unit 233 compares the init ial image P10
with the current image P20 and shifts the current image P20 so that the current
image P20 most closely matches the initial image P10. Fig. 11 is a view showing
25 the state where the current image P20 is superimposed on the initial image P10 so
that they match. It is assumed that the building 20, which has appeared in the
right of the center in the initial image P10, appears to the left in the current image
P20. In this case, it is found that the image center Oc of the current image P20 is
displaced to the right relative to the image center Oi of the initial image P 10.
30 [0032]
The displacement calculation unit 234 calculates the gap between the
current image P20 and the initial image P10 based on a result of matching by the
image matching processing unit 233 (ST140). In this example, i t is calculated
how many pixels are left as a gap. As shown in Fig. 12, it is assumed that the
11
crosswise direction is the x-axis direction and the lengthwise direction is the
y-axis direct ion in the display image. The displacement calculation unit 234
calculat es th e gap b y calculat in g how man y (ΔX) pix els in th e x -direct ion and how
man y (ΔY) pix els in t he y-direction the current image P20 is deviated from the
initial image P105 .
[0033]
After the posit ion of the current image P20 is obtained (ST140), it is
determined whether the gap is within the allowable range. This processing is
performed by the central control uni t 210. It is assumed that the allowable range
10 is preset to the central control unit 210. Fo r ex ampl e, it is ass umed t hat εx and ε y
are set as the allowable range of the gap.
[0034]
The central control unit 210 comp ares th e gap (ΔX, ΔY) wi th th e allowable
ran ge (εx , ε y) . Wh en th e gap (ΔX, ΔY) is wit hin th e al lowab le ran ge (εx , ε y) , th e
15 control loop is returned to ST130. Not e t hat, ΔX≤εx and ΔY≤ε y ar e s atis fi ed
wh en t he gap (ΔX, ΔY) is withi n th e all owable r an ge ( εx , ε y) .
[0035]
On the other hand, when th e gap (ΔX, ΔY) is o utsid e th e allowable r an ge
(εx , ε y) , th e ori ent ati on adju stment of th e ant enn a unit is per fo rmed (ST 170).
20 Note that ΔX>εx an d /or ΔY>ε y ar e sat isf ied wh en th e gap (ΔX, ΔY) is ou tsid e t he
allowabl e ran ge (εx , ε y) .
[0036]
A direct ion in which the current position is displaced with respect to the
initial position is known by the calculation of the gap. Thus, the rotating table
25 122 and the turning table 123 are turned t o can cel t he gap (ΔX, ΔY).
Specifically, drive signals are sent from the motor driver 220 to the rotating motor
124 and the turning motor 125.
[0037]
Note that , although it is known how many pixels the cur rent position is
30 deviated in the image taken, the actual "amount" is not known. In other words,
even if th e gap (ΔX, ΔY) i n th e image is k nown, it is not poss ib le t o o btai n a
specific number of degrees of the angle the antenna unit 110 should be turned in
the azimuth or elevat ion (depression) direction. (To accurately obtain this value,
it would be necessary that a precise distance between the antenna device 100 and
12
the opposite station 20 is given.)
[0038]
Thus, when driving the motors 124 and 125, a predetermined amount
(number) of pulse signals are appl ied to the motors 124 and 125 for micro driving
of the motors 124 and 125. After that, the control operation is returned to ST135 0
and it is determined whether there is a remaining gap (ST150), and micro driving
of the motors 124 and 125 is repeated unti l the gap falls within the allowable
range. Then, the antenna unit 110 turns in the direction of the opposite station 20
as shown in Fig. 13.
10 [0039]
In this manner, by performing posit ion feedback contro l on the basis of a
camera image in ST130 to ST170, it is possible to always set the direction of the
antenna unit 110 toward the opposite station 20 even when a vibration is appl ied to
the lamp post 50.
15 [0040]
According to the first exemplary embodiment with the above-described
structure, the following advantageous effects can be obtained.
(1) According to this exemplary embodiment, it is possible to
automatically adjust the direction of the antenna unit 110 so that it is oriented
20 toward the opposite station 20. In this exemplary embodiment , position feedback
based on a camera image, not feedback control based on the reception strength
level, is performed. If feedback control is performed based on the reception
strength level, control collapses when a mechanical vibration occurs in the
opposite station 20, for example. On the other hand, when position feedback
25 based on a camera image is performed l ike in this exemplary embodiment , the
antenna unit 110 can be oriented in the direction of the opposite station 20
regardless of the state of the opposite stat ion 20 (regardless of the reception
strength level). This is significantly effective in the circumstances where a
mechanical vibration occurs in both the antenna i tself and the opposite station 20
30 like in city areas.
[0041]
(2) The displacement of the antenna device 100 due to a mechanical
vibration and the swinging of the antenna unit 110 by rotation and turn driving can
be detected by a camera image. Thus, in this exemplary embodiment, there is no
13
need for an expensive sensor (for example, a highly accurate rotary encoder,
angular velocity sensor etc. ) or the l ike for detecting the azimuth and the elevat ion
of the antenna unit 110 with high accuracy (for example, at 0.1° or less). This
contributes to size and cost reduction.
[00425 ]
Differences between the exemplary embodiment and the related art are
described for reference.
Although, in this exemplary embodiment , a camera is used as a sighting
device or the like, this exemplary embodiment is different from Japanese
10 Unexamined Patent Application Publications Nos. 2007-33380, 2007-88576 and
2005-72780 in which a camera is used as a sight ing device in the antenna
installat ion stage (Japanese Unexamined Patent Appl ication Publications Nos.
2007-33380, 2007-88576 and 2005-72780 are collectively referred to as related art
literature). In the related art literature, the optical axis of the camera and the
15 transmitting and receiving direction of the antenna unit are aligned in advance.
Then, the orientation of the antenna is adjusted so that an opposi te station appears
at the center of the camera image. The antenna unit is thereby oriented to the
opposite station accurately, which achieves the maximum reception strength
according to the related art literature.
20 [0043]
On the other hand, in this exemplary embodiment, the orientation of the
antenna unit is previously set in a direction in which the maximum reception
strength is achieved by some means. The camera is installed after that . Then,
feedback control is performed so that a certain landmark (the building 30 in the
25 above-described example) does not move in the imaging area even when a
mechanical vibration occurs, and thereby the antenna unit is always oriented to the
opposite station.
[0044]
There is a case where the radio wave emitt ing direction (radio wave
30 receiving direct ion) of the antenna unit is deviated from a designed direction or the
optical axis of the camera is deviated from a designed direction. In such a case, it
is apparent that the techniques of the related art literature do not work well in the
antenna installation stage. On the other hand, in this exemplary embodiment, it is
not at all necessary for the opt ical axis of the camera and the transmi tting and
14
receiving direction of the antenna unit to be aligned, and it is only necessary to
register the camera image when the recept ion strength level is maximum as the
initial image. As a mat ter of course, the related art l iterature disclose s nothing
about position feedback control on the basi s of the camera image after the antenna
installat ion5 .
[0045]
It should be noted that the present invention is not limited to the
above-described exemplary embodiment and may be varied in many ways within
the scope of the present invention.
10 The functional uni ts of the direction adjustment control unit 200 may be
dedicated hardware composed of various logical elements. Al ternatively, the
functions of the central control uni t 210 and the image processing unit 230 may be
implemented by incorporating a given program into a computer having a CPU
(Central Processing Device), a memory (storage device) and the like. The
15 above-described functional units may be implemented by instal ling an antenna
orientation adjustment program to the memory in the computer having the CPU and
the memory through a communication means such as the Internet or a nonvolatile
recording medium such as a CD-ROM or a memory card and causing the CPU or
the like to operate wi th the installed program. The program may be installed by
20 directly inserting the memory card, the CD-ROM or the like into the computer or
externally connect ing equipment that reads such as a storage medium to the
computer. Further , the program may be supplied and installed through
communicat ion by connecting a LAN cable, a wired or wireless communication
line to the computer.
25 [0046]
In some structure of the antenna device, the azimuth and the elevation can
be made variable by one orientation adjustment part . Such an antenna device is
disclosed in Japanese Unexamined Patent Application Publication No. H5-67909,
for example. In this case, only one motor is used.
30 [0047]
The reception strength level may be measured, and, for example, when the
average reception strength per unit time falls below a specified threshold, the
automatic orientat ion adjustment in the above -described exemplary embodiment
may be carried out.
15
[0048]
A function of updating the ini tial direction at regular or irregular intervals
may be added. Specifically, the angle position of the antenna unit 110 at which
the reception strength is maximized may be automatically obtained and set as a
new ini tial direction5 .
For example, the direction of the antenna unit is varied in a specified range
by the driving of a motor -driven (i .e., electrically-driven) uni t (the rotating motor
124 and the turning motor 125). At this time, an image taken by the camera 130
and the reception strength of radio waves received by the antenna unit 110 are
10 recorded. Then, the angle position of the antenna uni t 110 in which the recept ion
strength is maximized is obtained.
[0049]
Note that, although it is most preferable to find "the direction in which the
reception strength is maximized", a certain deviation is al lowed for the ini tial
15 direction as long as i t is within a range where the reception strength level, BER
(bit error rate) or SNR (signal to noise ratio) satisfies a specified level (good radio
wave communication is achieved).
[0050]
This applicat ion is based upon and claims the benefit of priority from
20 Japanese patent applicat ion No. 2014-35472, filed on February 26, 2014, the
disclosure of which is incorporated herein in its entirety by reference.
Reference Signs List
[0051]
10 ANTENNA
25 20 OPPOSITE STATION
40 STRUCTURE
50 LAMP POST
51 DIRECTIONAL BEAM
60 INSTALLATION BASE
30 61 L-SHAPED MEMBER
62 BRACKET
63 BOLT
64 NUT
100 ANTENNA DEVICE
16
110 ANTENNA UNIT
120 PAN HEAD
121 BASE TABLE
122 ROTATING TABLE
123 TURNING TABL5 E
124 ROTATING MOTOR
125 TURNING MOTOR
130 CAMERA
140 CONTROL UNIT
10 141 HOUSING
150 TRANSMITTING AND RECEIVING UNIT
151 RECEIVING CIRCUIT
152 TRANSMITTING CIRCUIT
200 DIRECTION ADJUSTMENT CONTROL UNIT
15 210 CENTRAL CONTROL UNIT
220 MOTOR DRIVER
230 IMAGE PROCESSING UNIT
231 IMAGE CAPTURE UNIT
232 INITIAL IMAGE RECORDING UNIT
20 233 IMAGE MATCHING PROCESSING UNIT
234 DISPLACEMENT CALCULATION UNIT
17

WE CLAIM:
1. An antenna device comprising:
an antenna unit;
a camera unit fixed so that its direction relative to the antenna unit doe5 s
not change; and
a direction adjustment control unit that adjust s a direction of the antenna
unit, wherein
the direction adjustment control unit controls to return the direction of the
10 antenna unit back to an initial direction based on an image taken by the camera
unit.
2. The antenna device according to Claim 1, wherein
when the antenna uni t is oriented in the initial direction, the antenna unit
15 is oriented in a direct ion in which it can perform good wireless communication
with an opposite station,
the camera unit captures an arbitrary object in an imaging area when the
antenna unit is oriented in the initial direction, and
the direction adjustment control unit adjusts the direction of the antenna
20 unit based on a direct ion in which the object is displaced in the imaging area.
3. The antenna device according to Claim 1 or 2, wherein
the direction adjustment control unit has a function of automatically
changing the direct ion of the antenna unit and updat ing the ini tial direction based
25 on an image taken by the camera unit and a radio wave strength received by the
antenna unit .
4. A control method of an antenna device including an antenna unit
mounted so that its direction is adjustable, a motor-driven unit that changes a
30 direction of the antenna unit , a camera uni t fixed so that its direction relative to
the antenna unit does not change, and a direction adjustment control unit that
supplies a drive signal to the motor -driven unit and adjusts the direction of the
antenna unit , the method comprising:
control ling to return the direction of the antenna unit back to an initial
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direction based on an image taken by the camera unit.