1. A radio wave reflection device that relays, by reflection, radio communicat ions between a first antenna device and a second antenna device distant from each other, comprising5 : a mounting unit that securely mounts the radio wave reflection device on a stable installation place; a reflector unit that holds two reflectors; and a joint unit that connects the reflector unit and the mounting unit, wherein 10 the two reflectors are respectively held at a specified til t angle with respect to support shafts, have reflective surfaces facing each other, are coaxial with each other , and at least one of the two reflectors is rotatable about the support shaft, and the joint uni t has rotational freedom along two axes orthogonal to each 15 other.

2. The radio wave reflection device according to Claim 1, wherein the two reflectors are respect ively held at a tilt angle of 45º with respect to the support shafts. 20

3. The radio wave reflection device according to Claim 1 or 2, further comprising: an angle measurement means that measures an elevation angle and an azimuth angle of the reflector unit, wherein 25 a main scope that is displaced together wi th the reflector unit can be attached to the reflector unit .

4. The radio wave reflection device according to Claim 3, wherein the angle measurement means is an angle scale for reading a rotat iona l angle of each 30 rotational axis of the joint unit.

5. The radio wave reflection device according to Claim 3, wherein the angle measurement means is one of an acceleration sensor and a gyro sensor incorporated into the reflector unit. 24

6. The radio wave reflection device according to any one of Claims 1 to 5, wherein a scope can be attached to a rotat ing support shaft of each of the two reflectors. 5

7. The radio wave reflection device according to any one of Claims 1 to 6, wherein an angle scale for reading a rotational angle is placed on a rotating support shaft of each of the two reflectors. 10 8. A method for installing a radio wave reflection device that relays , by reflection, radio communications between a first antenna device and a second antenna device distant from each other, the radio wave reflection device including a mounting unit that securely mounts the radio wave reflection device on a stable installat ion place, a reflector unit that holds two reflectors at a t ilt angle of 45º and 15 which reflectors are coaxial and rotatable independently of each other , and a joint unit that connects the reflector unit to the mounting unit and has rotat ional freedom along two axes orthogonal to each other , the method comprising: measuring a direction of the firs t antenna device and a direction of the second antenna device; 20 specifying a plane of incidence defined by the first antenna device, the second antenna device and the radio wave reflection device; adjusting an angle of the joint uni t so that a normal to the plane of incidence and a rotational axis of the two reflectors coincide with each other ; and pointing the two reflectors respectively in the direction of the first antenna 25 device and the direct ion of the second antenna device.

DESCRIPTION
RADIO WAVE REFLECTION DEVICE
Technical Field
[0001]
The present invention relates to a radio wave reflection device5 .
Specifically, the present invention relates to a radio wave reflection device that
relays radio waves for wireless communications by means of reflection.
Background Art
[0002]
10 As a wireless system for mobile backhaul , a point -to-point system using
parabolic antennas is used. Because i t is necessary to provide an unobstructed
view between the antennas to achieve favorable communications, the antennas are
often placed in a high position in order to obtain an unobstructed view.
[0003]
15 Cells for mobile base stat ions tend to decrease in size, such as picocells
and femtocells. Accordingly, a base station needs to be placed at a lower
position; however, an environment with an unobstructed view cannot be obtained
when antennas are placed at lower posi tions in an urban area, which makes it
difficult to implement point-to-point wireless communications . Techniques to
20 overcome this problem by relaying radio waves by reflection on a reflector in the
situation where there is an unobstructed view between two antennas are known
(Patent Literature 1 to 6).
Citation List
Patent Literature
25 [0004]
PTL1: Japanese Unexamined Patent Publ ication No. S58-73205
PTL2: Japanese Unexamined Patent Publ ication No. H07-154320
PTL3: Japanese Unexamined Patent Publ ication No. 2007-299232
PTL4: Japanese Unexamined Patent Publ ication No. 2006-245886
30 PTL5: Japanese Uti li ty Model No. 3108453
PTL6: Japanese Unexamined Patent Publ ication No. 2012-199617
Summary of Invention
Technical Problem
[0005]
3
The methods of relaying radio waves by reflection disclosed in the above
literature simply relay radio waves using one reflector. It is possible with one
reflector to reflect radio waves so as to divert the waves around an obstacle.
However, in the case of reflecting radio waves with one reflector, it is difficult to
achieve high reflection intensity when the angle of incidence is large, and in such 5 a
case it is necessary to use a significantly large reflector to obtain sufficient
reflection intensity.
[0006]
Further, although it is possible to relay radio waves by reflect ion in
10 principle, it is very difficult in practice to adjust the angle of a reflector and set it
up so as to obtain a good reception level. Patent Literature 4 to 6 disclose a solid
plate reflector with a mechanism capable of angle adjustment , and it is possible in
theory to make a fine adjustment of the angle of the reflector to obtain the
maximum reception level by using such an angle adjustment mechanism.
15 However, assume a case where, for example, a reflector is placed so as to
relay radio waves between a first antenna and a second antenna. In this case, it
would be necessary to try to maximize the recept ion level of the second antenna by
making various changes in the orientation of the first antenna, the orientat ion of
the reflector and the orientation of the second antenna. There are at least three
20 parameters: the orientation of the first antenna, the orientation of the reflector and
the orientat ion of the second antenna, each of which is a vector in a
three-dimensional space. As a practical matter, it would be almost impossible to
adjust these orientations by trial and error , checking the reception level each time.
[0007]
25 An exemplary object of the present invention is to provide a radio wave
reflection device that can relay radio waves at a sufficient reflection intensity.
Further, another exemplary object of the present invention is to provide a radio
wave reflection device that can adjust the direction easily and accurately.
Solution to Problem
30 [0008]
A radio wave reflection device according to the exemplary aspects of the
present invention is a radio wave reflection device that rela ys, by reflection, radio
communicat ions between a first antenna device and a second antenna device
distant from each other, including a mount ing unit that securely mounts the radio
4
wave reflection device on a stable instal lat ion place, a reflector unit tha t holds two
reflectors, and a joint unit that connects the reflector unit and the mounting unit ,
wherein the two reflectors are respectively held at a specified t i lt angle with
respect to support shafts, have reflective surfaces facing each other, are coax ial
with each other, and at least one of the two reflectors is rotatable about the suppor5 t
shaft, and the joint unit has rotational freedom along two axes orthogonal to each
other.
[0009]
A method for instal ling a radio wave reflection device according to the
10 exemplary aspects of the present invention is a method for installing a radio wave
reflection device that relays, by reflection, radio communications between a first
antenna device and a second antenna device distant from each other, the radio
wave reflection device including a mounting unit that securely mounts the radio
wave reflection device on a stable instal lat ion place, a reflector unit that holds two
15 reflectors at a ti lt angle of 45º and which reflectors are coaxial and rotatable
independently of each other, and a joint unit that connects the reflector unit to the
mounting unit and has rotational freedom along two axes orthogonal to each other,
the method including measuring a direction of the first antenna device and a
direction of the second antenna device, specifying a plane of incidence defined by
20 the first antenna device, the second antenna device and the radio wave reflection
device, adjusting an angle of the joint uni t so that a normal to the plane of
incidence and a rotational axis of the two reflectors coincide with each other, and
pointing the two reflectors respect ively in the direction of the first antenna device
and the direction of the second antenna device.
25 Advantageous Effects of Invention
[0010]
According to the exemplary aspects of the present invention, it is possible
to provide a radio wave reflection device that relays radio communications
between a first antenna device and a second antenna device at a sufficient
30 reflection intensity.
Brief Description of Drawings
[0011]
Fig. 1 is a view showing a communication system;
Fig. 2 is a view showing a radio wave reflection device;
5
Fig. 3 is a view showing the structure of a joint unit;
Fig. 4 is a view i llustrat ing the path of radio waves in a reflection unit;
Fig. 5 is a view showing a detachable scope;
Fig. 6 is a flowchart showing an installation procedure of the radio wave
reflection device5 ;
Fig. 7 is a flowchart showing an installation procedure of the radio wave
reflection device;
Fig. 8 is a view i llustrat ing parameters;
Fig. 9 is a view exemplifying an angle meter at tached to a support shaft;
10 Fig. 10 is a view exemplifying a theodolite; and
Fig. 11 is a view showing the way of adjusting the orientation of a
reflector wi th laser light.
Description of Embodiments
[0012]
15 Exemplary embodiments of the present invention are illustrated in
drawings and described with reference to symbols denot ing elements in the
drawings.
(First exemplary embodiment)
A first exemplary embodiment of the present invention is described
20 hereinafter.
Fig. 1 shows a communication system 100.
The communication system 100 includes a first antenna device 110 and a
second antenna device 120, and transmits and receives communication radio waves
between the first antenna device 110 and the second antenna device 120. The
25 first antenna device 110 and the second antenna device 120 transmit and receive
radio waves by direct ional antennas such as parabolic antennas. Note that, in
view of a demand for a rapid increase in channel capacity, a wider bandwidth, a
higher frequency and the like, today radio waves have wavelengths of mi llimeters,
and the beam width is extremely narrow.
30 [0013]
It is assumed that there is no direct view between the first antenna device
110 and the second antenna device 120 due to an obstacle 10 between the first
antenna device 110 and the second antenna device 120. The obstacle 10 is
typically an artificial structure l ike a house or a building, though it may be a
6
mountain or the l ike. Given this situation, a radio wave reflection device 200 is
placed as a part of the communication system 100, so that the radio wave reflection
device 200 reflects radio waves to divert the waves around the obstacle 10.
Point-to-point communications are thereby implemented between the first antenn a
device 110 and the second antenna device 120. This exemplary embodiment i5 s
characterized in the structure of the radio wave reflect ion device 200 and a method
of appropriately installing the radio wave reflection device 200.
This above structure and method are described hereinafter.
[0014]
10 Fig. 2 shows the radio wave reflection device 200.
The radio wave reflection device 200 includes a mounting unit 210, a joint
unit 220, and a reflector unit 300.
[0015]
Ideal ly, the radio wave reflection device 200 is placed at a high position,
15 and, it is supported at the high position by use of a pole 20 or a building. In Fig.
2, the pole 20 is placed to support the radio wave reflection device 200 at a high
position. The structure of the mounting unit 210 is not particularly limited as
long as it can securely mount the radio wave reflection device 200 on the pole 20.
For example, the mounting unit 210 may have a structure to hold the pole 20 by
20 two plates 211 and 211, as shown in Fig. 2.
[0016]
The joint unit 220 connects the mounting unit 210 and the reflector unit
300 so that the posture of the reflector unit 300 can be changed with respect to the
mounting unit 210 (or the pole 20). The joint unit 220 may be a universal joint,
25 which is well known, and preferably, it has a scale that measures both the azimuth
angle and the elevation angle and that is easy to read. Thus, the structure of the
joint unit 220 preferably has rotat ional freedom along two axes orthogonal to each
other. Although a universal joint with a cross spider can be used from this
perspective, a joint structure in which the AZ axis (vertical axis) and the EL axis
30 (horizontal axis) are separated as shown in Fig. 3 is more preferable.
[0017]
The joint unit 220 has two axes that are orthogonal to each other as
rotational axes. (To be exact , the two axes are not "orthogonal" but are spatially
7
skewed. The two axes become orthogonal when one axis is projected to overlap
the other axis. )
When installing the radio wave reflection device 200, it is preferred to
make an adjustment so that one of the two axes is oriented vertically and the other
axis is oriented horizontally. Thus, the vert ical axis is referred to as the AZ axis5 ,
and the horizontal axis is referred to as the EL axis. Thus, by the rotation about
the AZ axis, the azimuth angle of the reflector unit 300 changes. By the rotation
about the EL axis, the elevation angle of the reflector unit 300 changes.
[0018]
10 The angles are referred to as follows. Al though it is general that the
positive angle from horizontal is referred as the elevation angle and the
negative angle from horizontal is referred as the depression angle with respect to
the horizontal plane, the angle in the pitch direction is referred to as the elevation
angle in this specification without differentiating the depression angle from the
15 elevation angle. Further, for example, the angle from the vertical line, not wi th
respect to the horizontal plane, is also referred to as the elevation angle.
[0019]
In Fig. 3, the joint uni t 220 includes a fixed part 230 that is formed
integrally with the mounting unit 210, a rotating part 240 that is held (rotatably
20 supported) by the fixed part 230 with respect to the AZ axis as a rotational axis,
and a coupl ing unit 250 formed integrally with the backside of the reflector unit
300 and held (rotatably supported) by the rotating part 240 with respect to the EZ
axis as a rotational axis.
[0020]
25 The fixed part 230 has two support pieces 231 and 231 that are shaped like
the letter L from the base surface when viewed from the side, and the two support
pieces 231 and 231 are parallel to and opposite to each other wi th a specified gap
therebetween. The specified gap is the interval along the AZ axis (vertical axis).
Each of the two support pieces 231 and 231 has a hole 232 (which may be a
30 projection or a depression) on one virtual line along the AZ axis (vertical axis) to
rotatably support the rotating part 240. As shown in Fig. 3, a scale 233 for
measuring an angle is engraved on the outer surface of the support piece 231.
This angle scale 233 is an angle scale for measuring the azimuth (AZ) angle. A
part of the outer edge of the support piece 231 is arc-shaped so that the relative
8
angle position of a reference mark 242 placed on the rotating part 240 can be easily
read.
[0021]
The rotat ing part 240 has two coupling pieces 241 and 241 on the backside
of the base surface and has two support pieces 245 and 245 on the front sid5 e
thereof. The side of the rotating part 240 which faces the reflector unit 300 is
referred to as the front side, and the side of the rotating part 240 which faces the
mounting unit 210 is referred to as the backside. The coupling pieces 241 and
241 are shaped like the letter L from the base surface when viewed from the side
10 and rotatably supported by the support pieces 231 and 231 of the fixed part 230.
Because the coupling pieces 241 and 241 are rotatably supported by the support
pieces 231 and 231 of the fixed part 230, the rotating part 240 can rotate in the
azimuth (AZ) direction. The outer surface of the coupling piece 241 has the
reference mark 242 which indicates the relative angle position to the angle scale
15 233 for measuring the azimuth angle (AZ). When placing the reference mark 242
on the outer surface of the coupl ing piece 241, the reference mark 242 may be
engraved on the outer surface of the coupling piece 241, or it may be a detachable
sticker.
[0022]
20 The support piece 245 is shaped like the letter L from the base surface
when viewed from the front, and the two support pieces 245 and 245 are parallel to
and opposite to each other along the EL axis (horizontal axis) with a specified gap
therebetween. Each of the two support pieces 245 and 245 has a hole 246 (which
may be a projection or a depression) on one virtual line along the EL axis
25 (horizontal axis) to rotatably support the coupling unit 250. A scale 247 for
measuring an angle is engraved on the outer surface of each of the support pieces
245. This angle scale 247 is an angle scale for measuring the elevation angle
(EL). A part of the outer edge of each of the support pieces 245 and 245 is
arc-shaped so that the relative angle posit ion of a reference mark 251 placed on the
30 coupling unit 250 can be easi ly read.
[0023]
When placing the reference mark 251 on the outer surface of the coupling
unit 250, the reference mark 251 may be engraved, or it may be a detachable
sticker.
9
[0024]
With the joint unit 220 having the above structure, it is possible to change
the azimuth angle and the elevation angle of t he reflector unit 300 independently
of one another and it is also possible to read the azimuth angle and the elevation
angle independently of one another5 .
[0025]
The structure of the reflector unit 300 is described hereinafter.
The reflector unit 300 includes a radome 310, a support frame 320, a first
support shaft (rotating support shaft) 330, a second support shaft (rotating support
10 shaft) 340, a first reflector 350, a second reflector 360, and three scopes
(collimators). (Note that, in Fig. 2, the radome 310 is shown by a chain line so
that the inside of the radome 310 is visible.)
[0026]
The support frame 320 is U-shaped with right angled corners as a whole.
15 Specifically, the support frame 320 has a U-shape wi th right angled corners as a
whole with support arms 322A and 322B extending horizontal ly from the upper
and lower ends of a column 321 located vertically. The upper support arm is
referred to as a first support arm 322A, and the lower support arm is referred to as
a second support arm 322B. When the side of the column 321 from which the
20 support arms 322A and 322B extend is the front side, and the opposite side is the
backside, the backside of the column 321 serves as the coupling unit 250 and is
supported axially by the rotating part 240 of the joint unit 220. In the space
between the first support arm 322A and the second support arm 322B of the
support frame 320, the space has the column 321 in one direction corresponding to
25 the backside, and the space is open in the other directions, thereby letting radio
waves in and out over a wide angle.
[0027]
The first support shaft 330 is placed to hang down vertically from the first
support arm 322A. Further, the first support shaft 330 is borne by the first
30 support arm 322A so that it can rotate about its axis line as the rotational axis.
The second support shaft 340 is placed to rise from the second support arm 322B.
Further, the second support shaft 340 is borne by the second support arm 322B so
that it can rotate about its axis line as the rotat ional axis. The axis line
(rotat ional axis) of the first support shaft 330 and the axis line (rotational axis) of
10
the second support shaft 340 are designed to be on one virtual axis line. (Thus,
the first support shaft 330 and the second support shaft 340 are coaxial to each
other.) This virtual axis line is referred to as a main axis line L of the reflector
unit 300.
[00285 ]
The first reflector 350 is fixed to the first support shaft 330 at a specified
tilt angle. In this example, the first reflector 350 is fixed to the first support shaft
330 at a tilt angle of 45º. Likewise, the second reflector 360 is fixed to the
second support shaft 340 at a specified tilt angle. To be specific, the second
10 reflector 360 is fixed to the second support shaft 340 at a til t angle of 45º. The
reflective surfaces of the first reflector 350 and the second reflector 360 are
substantially face to face, though not actually "opposite" to each other because
they are til ted at 45º. Thus, as shown in Fig. 4, it is possible to reflect radio
waves emitted from one antenna device (the first antenna device 110) by the first
15 reflector 350 to let them enter the second reflector 360, and further reflect them by
the second reflector 360 toward the other antenna device (the second antenna
device 120). Note that, however, it is necessary to accurately adjust the
orientation of the main axis line L of the reflector unit 300 in order to relay radio
waves between the first antenna device 110 and the second antenna device 120
20 through such a reflection path, which is described later.
[0029]
The three scopes are respectively referred to as a main scope 370, a first
scope 371, and a second scope 372. The main scope 370 is fixed to the support
frame 320, and therefore the main scope 370 and the support frame 320 are
25 displaced together. In other words, the main scope 370 is displaced together with
the whole reflector unit 300.
[0030]
When mounting the main scope 370 on the support frame 320, it is placed
so that the optical axis of the main scope 370 is orthogonal to the main axis line L
30 of the reflector unit 300. (To be exact, the optical axis of the main scope 370 and
the main axis line L of the reflector unit 300 may be spatially skewed, not
"orthogonal" to each other; however, in this case also, it is preferred that the two
axes become orthogonal when the optical axis of the main scope 370 is projected to
overlap the main axis line L of the reflector uni t 300.) Although the significance
11
of this arrangement will become apparent in an angle adjustment procedure
described later, briefly this significance is as follows. Because the first reflector
350 and the second reflector 360 are arranged to be tilted at 45º, it is possible to
relay radio waves from the first antenna device 110 to the second antenna device
120 when the plane of incidence defined by the first antenna device 110, th5 e
second antenna device 120 and the radio wave reflection device 200 and the main
axis line L of the reflector unit 300 become orthogonal to each other. It is thus
necessary to adjust the posture of the reflector unit 300 so that the main axis line L
of the reflector unit 300 becomes orthogonal to the plane of incidence. If the
10 optical axis of the main scope 370 and the main axis l ine L of the reflector unit 300
are orthogonal to each other, it is easy to adjust the orientation of the main axis
line L of the reflector unit 300 by use of the main scope 370.
[0031]
Although the direction toward which the sight line of the main scope is
15 pointed is not particularly significant , it would be natural and user-friendly to
align the direction in which the support arms 322A and 322B extend and the
direction of the sight line of the main scope 370, judging from the shape of the
reflector unit 300 as a whole.
[0032]
20 The first scope 371 is attached to the first support shaft 330, and the
second scope 372 is attached to the second support shaft 340. They are mounted
so that the optical axis of the first scope 371 is orthogonal to the first support shaft
330, and the opt ical axis of the second scope 372 is orthogonal to the second
support shaft 340.
25 [0033]
It is necessary to align the orientation of the surface of each reflector and
the orientat ion of the optical axis of each scope. For this purpose, the normal to
the reflector and the optical axis of the scope are designed to be contained in the
same virtual plane. Stated differently, the optical axis of the scope intersects the
30 virtual plane containing the reflector at 45º . The important point is that a point at
which the scope is aimed serves as the point of transmission or reception of radio
waves.
[0034]
12
Note that , the main scope, the first scope and the second scope are not
necessarily used simultaneously. Instead, they may be used sequent ially, as is
described later in the angle adjustment procedure. Thus, as shown in Fig. 5, it is
feasible to place mounting units 370A, 371A and 372A for attaching and detaching
the main scope 370, the first scope 371 and the second scope 372, respectively, an5 d
attach one scope 373 to a specified position each for use.
[0035]
(Installation Procedure of Radio Wave Reflection Device 200)
An installation procedure of the radio wave reflection device 200 is
10 described hereinafter.
Figs. 6 and 7 are flowcharts showing the installation procedure of the radio
wave reflection device 200.
Fig. 8 illustrates parameters for reference.
First, the radio wave reflection device 200 is attached to the pole 20
15 (ST110). Because various directions will be measured later, for easy and
intuitive understanding, the AZ axis of the joint unit 220 is set along the vertical
direction and the EL axis is set along the horizontal direct ion. Then, the
reference marks 242 and 251 point at 0º (zero) of the angle scale 233 and the angle
scale 247. In this state, the vertical direction is along the z axis, and the
20 horizontal direct ion is at the elevation angle of 90º . Thus, the elevation angle is
measured as an angle with respect to the vertical direction (z axis). A direction at
the azimuth angle of 0º (zero) is not particularly limited. An arbitrary direction
may be set as a direct ion at the azimuth angle of 0º (zero) , which serves as a
reference for azimuth angle measurement .
25 The direction at the azimuth angle of 0º (zero) is the x axis. The azimuth
angle is measured as an angle wi th respect to the x axis.
[0036]
Next, the main scope 370 is aimed at the first antenna device 110 (ST120).
At this time, rotation occurs around the AZ axis and the EL axis of the joint unit
30 220. Accordingly, the values of the angle scale 233 and the angle scale 247
indicate the direction of the first antenna device (ST130). A unit vector
indicating the direct ion of the first antenna device from the origin at the position
of the radio wave reflection device 200 is referred to as a vector a. (Although it
is desirable in fact to display an ar row (→) abov e th e s ymbol "a" of the vector a or
13
display "a" in bold type, it is not possible to do so due to the limits of the display
function. Please be aware of the meaning and read it appropriately. ) The
direction of the first antenna device 110 (vector a) is represented in
three-dimensional polar coordinates (spherical coordinates). It is assumed that an
an gl e f rom th e z ax is is θ1, and an an gle f rom t he x ax is is φ15 .
[0037]
a=(1, θ1, φ1)
[0038]
Likewise, the main scope 370 is aimed at the second antenna device 120
10 (ST140). Then, the direction of the second antenna device 120 (vector b) is
measured (ST150). The direction of the second antenna device 120 (vector b) is
represented by an an gl e θ2 from the z axis and an an gl e φ2 from the x axis.
[0039]
b=(1, θ2, φ2)
15 [0040]
The directions of the first antenna device 110 and that of the second
antenna device 120 are now known. In other words, the plane of incidence
defined by the first antenna device 110, the second antenna device 120 and the
radio wave reflection device 200 is obtained. The next thing is to make the main
20 axis line L of the reflector unit 300 perpendicular to the plane of incidence.
[0041]
Although there are various methods for making the main axis line L of the
reflector unit 300 perpendicular to the plane of incidence, a method that points the
reflector unit at the direction of the midpoint is described in this example. The
25 midpoint direction is a coined expression in this specification which means the
direction of the midpoint P between the first antenna device 110 and the second
antenna device 120.
[0042]
Because the direction of the first antenna device 110 (vector a) and the
30 direction of the second antenna device 120 (vector b) are already obtained, a unit
vector p (vector p) in the midpoint direction is calculated as follows (ST160).
[0043]
p=(a+b)/ |a+b|
[0044]
14
It is assumed th at, as the mid point di r ecti on p , an an gle θ 3 from the z axis
and an an gl e φ3 from the x axis are obtained. The direction of the reflector unit
300 is aligned in the midpoint direction by using the angle scale 247 and the angle
scale 233 (ST170). Consequently, the main axis line L of the reflector unit 300
becomes perpendicular to the plane of incidence. The angle of the joint unit 5 220
is fixed in this state.
[0045]
After that, the first scope 371 is aimed at the first antenna device 110
(ST180). Then, the first reflector 350 is turned in the direction of the first
10 antenna device 110. Further, the second scope 372 is aimed at the second antenna
device 120 (ST190). Then, the second reflector 360 is turned in the direction of
the second antenna device 120. The first support shaft 330 and the second
support shaft 340 are fixed in this state.
[0046]
15 It is thereby possible to relay radio waves between the first antenna device
110 and the second antenna device 120 by the reflection of the radio wave
reflection device 200.
Radio waves from the first antenna device 110 enter the first reflector 350.
Because the first reflector 350 is pointed in the direction of the first
20 antenna device 110 at this t ime, the angle of incidence when the radio waves from
the first antenna device 110 enter the first reflector 350 is 45º.
The radio waves reflected by the first reflector 350 enter the second
reflector 360. The angle of incidence when the radio waves enter the second
reflector 360 is also 45º. The radio waves are reflected by the second reflector
25 360. Because the second reflector 360 is pointed in the direction of the second
antenna device 120, the radio waves reflected by the second reflector 360 enters
the second antenna device 120. (The same applies to the case where radio waves
are emitted from the second antenna device 120 and received by the first antenna
device 110.)
30 [0047]
The following effects are obtained according to the above -described first
exemplary embodiment.
(1) The reflector consists of two plates: the first reflector 350 and the
second reflector 360, which can rotate independent ly of one another.
15
Thus, by pointing the first reflector 350 at the first antenna device 110 and
pointing the second reflector 360 at the second antenna device 120, it is possible to
reflect radio waves at a sufficiently high reflection intensity. In this exemplary
embodiment, the first reflector 350 and the second reflector 360 are each tilted at
45º with respect to the support shafts (330 and 340), and therefore the angle o5 f
incidence of each radio wave is 45º. Even if radio waves are not sharply incident
on the "radio wave reflection device 200" (the angle of incidence is large), this
does not cause any problem in this exemplary embodiment since the orientations of
the first reflector 350 and the second reflector 360 are independently adjustable.
10 Therefore, the radio wave reflection device can relay radio waves at a sufficient
reflection intensity regardless of the arrangement of the first antenna d evice 110,
the second antenna device 120 and the radio wave reflection device 200.
[0048]
(2) The mounting uni t 210 and the reflector unit 300 are connected by the
15 joint unit 220 having rotational freedom along two axes. It is thereby possible to
adjust the posture (orientation) of the reflector unit 300 after attaching the radio
wave reflection device 200 to the pole 20.
[0049]
(3) Because the joint unit 220 is provided with the angle scales 233 and
20 247, it is possible to measure the posture (angle) of the reflector unit. Further,
because the main scope 370 sequentially is aimed at the first antenna device 110
and the second antenna device 120, it is possible to measure the directions of the
first antenna device 110 and that of the second antenna device 120 from the radio
wave reflection device 200. In this manner, because the joint unit 220 is provided
25 with the angle scales 233 and 247 and further is provided with the main scope 370,
it is easy to make the main axis line L of the reflector unit 300 perpendicular to the
plane of incidence.
[0050]
(4) Further, it is provided wi th the first scope 371 and the second scope
30 372, it is easy to point the first reflector 350 at the first antenna device 110 and
point the second reflector 360 at the second antenna device 120 by aiming the
scopes 371 and 382.
[0051]
(Alternative Example 1)
16
In the above-described first exemplary embodiment , the direction of the
reflector unit 300 is aligned in the midpoint direction in ST170. However, i t is
not necessary to set the direction of the reflector unit 300 in the midpoint
direction, as the most important point is to make the main axis l ine L of the
reflector unit 300 perpendicular to the plane of incidence. Therefore, a norma5 l
vector n of the plane of incidence may be calculated, and the posture (angle) of the
reflector unit 300 may be adjusted so that the main axis line L coincides wi th the
normal vector n. Note that the normal vector n of the plane of incidence is
calculated by the outer product of the vector a and th e vector b (a×b).
10 [0052]
(Alternative Example 2)
In the above-described first exemplary embodiment , the first scope 371 is
mounted on the first support shaft 330, and the second scope 372 is mounted on the
second support shaft 340. In place of the first scope and the second scope, an
15 angle meter may be mounted on each of the first support shaft 330 and the second
support shaft 340. Fig. 9 shows an angle meter 341 by way of illustration. In
Fig. 9, the angle meter 341 for measuring a rotational angle is mounted on the
second support shaft . Because the direction of the second antenna device 120
(vector b) is already measured (ST150), it is possible to point the second reflector
20 360 at the second antenna device 120, whi le checking the scale of the angle meter
341. (Because the azimuth angle of the joint unit 220 is added, it is necessary to
subtract that value as a matter of course.)
[0053]
(Alternative Example 3)
25 In order to enhance the visibility by the scopes 370, 371 and 372, visible
light may be emit ted from the first antenna device 110 and the second antenna
device 120. The visible light may be flashing laser light, which is a so-called
searchlight , or the like.
[0054]
30 (Second Exemplary Embodiment )
In the above-described first exemplary embodiment , the joint unit 220 is
provided with the angle scales 233 and 247 to read the angle of the joint unit 220.
In a second exemplary embodiment, the case of measuring an angle using another
device without providing the radio wave reflection device 200 with an angle
17
measurement function is described. As an angle measurement device, a
theodolite 500 as shown in Fig. 10 is known, for example.
[0055]
The directions of the first antenna device 110 and the second antenna
device 120 are measured using the theodol it e 500. The vector a and the vector 5 b
are thereby obtained. The midpoint direction p is calculated from the vector a
and the vector b.
After obtaining the midpoint direct ion p, an object that exists when
viewing the midpoint direction p from the radio wave reflection device 200 is
10 specified. When the main scope 370 aims at the object, the reflector unit 300
turns to the midpoint direction p, and the main axis line L becomes perpendicular
to the plane of incidence at the same time. After that, the first scope 371 aims at
the first antenna device 110 (ST180), and the second scope 372 aims at the second
antenna device 120 (ST190).
15 [0056]
According to this structure, there is no need to put an angle scale on the
joint unit. This increases the range of choi ce for the joint uni t , such as a
universal joint.
[0057]
20 Note that , in the second exemplary embodiment also, it is not necessary to
point the reflector unit 300 at the midpoint direction p as long as the main axis line
L is perpendicular to the plane of incidence. It is only necessary to specify an
object that will be viewed by the main scope 370 when the main axis l ine L
becomes perpendicular to the plane of incidence and make the main scope 370 aim
25 at that object.
[0058]
(Third Exemplary Embodiment)
In the above-described exemplary embodiment , the aiming of the first
scope 371 is used to point the first reflector at the first antenna device 110
30 (ST180). Besides, i t is feasible to emit laser light from the first antenna device
110 to the radio wave reflection device 200, and seek the orientation at which the
reflection intensity of the laser light reaches its maximum, rotat ing the first
reflector 350. As shown in Fig. 11, a light receiving unit 610 is placed directly
below the first reflector 350, and the reception intensity is measured by a
18
measuring uni t 620. (The same applies for the second reflector 360.) This
eliminates the need to mount the scope on the first support shaft 330 or the second
support shaft 340.
[0059]
(Fourth Exemplary Embodiment5 )
In the above-described exemplary embodiment , it is assumed that the angle
(posture) adjustment of the joint unit 220 and the support shafts 330 and 340 is
made manual ly by a person.
In a fourth exemplary embodiment , the semi -automation of the direction
10 adjustment process in the radio wave reflection device is studied.
[0060]
Consider the automat ion of the aiming of the main scope 370, the first
scope 371 and the second scope 372 (e.g. ST120, ST140, ST180, ST190).
A digital imaging function (CCD or CMOS) and an image processing
15 function (image recognition function) may be incorporated to achieve this.
Then, it would be feasible to automate the measurement of the direction of
the first antenna device 110 (vector a) and the direction of the second antenna
device 120 (vector b) by means of emitting light from the antenna devices 110 and
120, for example.
20 [0061]
Consider the automat ion of the detect ion of the angle (posture) (e.g.
ST130, ST150).
To achieve this, a sensor (acceleration sensor, gyro sensor, rotary encoder)
may be mounted on each of the support frame 320, the first support shaft 330 and
25 the second support shaft 340. Alternatively, a sensor (rotary encoder) may be
mounted on each rotational axis (AZ axis, EL axis) of the joint unit 220.
[0062]
Consider the automat ion of the adjustment of the angle (posture) of the
first reflector and the second reflector. To achieve this, a motor may be
30 incorporated into each of the rotational axes (AZ axis, EL axis) of the joint unit
220, the first support shaft 330 and the second support shaft 340.
[0063]
Because an algorithm has become apparent from the above description, it
will be possible to create a computer program that automates the direction
19
adjustment in the radio wave reflection device and cause a computer to implement
this program.
[0064]
The computer may be a typical computer including CPU, ROM and RAM,
or a computer with dedicated hardware composed of various logic elements for th5 e
respective functional units. A direct ion adjustment program for a radio wave
reflection device can be stored and provided to the computer using any type of
non-transitory computer readable medium. The non -transitory computer readable
medium includes any type of tangible storage medium. Examples of the
10 non-transitory computer readable medium include magnetic storage media (such as
floppy disks, magnet ic tapes, hard disk drives, etc.), optical magnet ic storage
media (e.g. magneto-optical disks), CD-ROM (Read Only Memory), CD-R ,
CD-R/W, and semiconductor memories (such as mask ROM, PROM
(Programmable ROM), EPROM (Erasable PROM), flash ROM, RAM (Random
15 Access Memory), etc.). The program may be provided to a computer using any type
of transitory computer readable medium. Examples of the transi tory computer
readable medium include electric signals, optical signals, and electromagnetic
waves. The transitory computer readable medium can provide the program to a
computer via a wired communication line such as an electric wire or optical fiber
20 or a wireless communication line.
[0065]
(Summary)
Because a plurality of exemplary embodiments and alternative examples
are described above, a procedure necessary to install the radio wave reflection
25 device is summarized below.
There are broadly two things to be adjusted for installing t he radio wave
reflection device.
(Step 1) Make the main axis line of the reflector unit perpendicular to the
plane of incidence.
30 (Step 2) Point the first reflector and the second reflect respectively at the
first antenna device 110 and the second antenna device 120.
[0066]
For the above Step 1, the following steps are required.
(Step 1.1) Calculate the plane of incidence.
20
(Step 1.2) Adjust the angle so that the main axis l ine coincides with the
normal to the plane of incidence
[0067]
Further, for Step 1.1, the following step is required.
(Step 1.1.1) Measure the direction of the first antenna device 110 (vecto5 r
a) and the direction of the second antenna device 120 (vector b).
There are the following variations for the above Step 1.1.1
(Step 1.1.1A) Make the main scope aim at the antenna devices 110 and 120
and read the angle.
10 (Step 1.1.1B) Measure the directions of the antenna devices 110 and 120
by another equipment such as a theodolite.
[0068]
There are the following variations for the above Step 1.2
(Step 1.2A) Calculate the normal to the plane of incidence from the vector
15 a and the vector b and adjust the angle of the joint uni t 220 so that the main axis
line coincides with the normal
(Step 1.2B) Calculate the midpoint direction from the vecto r a and the
vector b and adjust the angle of the joint unit 220 so that the reflector unit points at
the midpoint direction.
20 [0069]
There are the following variations for the above Step 2.
(Step 2A) Aim at the first antenna device 110 and the second
antenna device 120 respectively using the first scope 371 and the second scope
372.
25 (Step 2B) Mount an angle meter on the first support shaft 330 and
the second support shaft 340 and adjust the angle.
(Step 2C) Receive laser light from the first antenna device 110 and
the second antenna device 120 and set it in the direction to maximize the reception
intensity.
30 [0070]
It should be noted that the present invention is not limi ted to the above -descr ibed
exemplary embodiment and may be var ied in many ways wi t hin the scope of the present
invention.
[0071]
35 This appl icat ion is based upon and claims the benefi t of pr ior i ty from Japanese
21
patent appl ication No. 2013-269028, f iled on December 26, 2013, the disclosure of which is
incorporated herein in i ts ent irety by reference.
Reference Signs List
[0072]
10 OBSTACL5 E
20 POLE
100 COMMUNICATION SYSTEM
110 FIRST ANTENNA DEVICE
120 SECOND ANTENNA DEVICE
10 200 RADIO WAVE REFLECTION DEVICE
210 MOUNTING UNIT
220 JOINT UNIT
230 FIXED PART
231 SUPPORT PIECE
15 232 HOLE
240 ROTATING PART
241 COUPLING PIECE
242 REFERENCE MARK
245 SUPPORT PIECE
20 246 HOLE
250 COUPLING UNIT
251 REFERENCE MARK
300 REFLECTOR UNIT
310 RADOME
25 320 SUPPORT FRAME
321 COLUMN
322A SUPPORT ARM
322B SUPPORT ARM
330 FIRST SUPPORT SHAFT
30 340 SECOND SUPPORT SHAFT
341 ANGLE METER
350 FIRST REFLECTOR
360 SECOND REFLECTOR
370 MAIN SCOPE
35 371 FIRST SCOPE
22
372 SECOND SCOPE
373 SCOPE
500 THEODOLITE
610 LIGHT RECEIVING UNIT
620 MEASURING UNI5 T
23
WE CLAIM:
1. A radio wave reflection device that relays, by reflection, radio
communicat ions between a first antenna device and a second antenna device
distant from each other, comprising5 :
a mounting unit that securely mounts the radio wave reflection device on a
stable installation place;
a reflector unit that holds two reflectors; and
a joint unit that connects the reflector unit and the mounting unit, wherein
10 the two reflectors are respectively held at a specified til t angle with
respect to support shafts, have reflective surfaces facing each other, are coaxial
with each other , and at least one of the two reflectors is rotatable about the support
shaft, and
the joint uni t has rotational freedom along two axes orthogonal to each
15 other.
2. The radio wave reflection device according to Claim 1, wherein the two
reflectors are respect ively held at a tilt angle of 45º with respect to the support
shafts.
20
3. The radio wave reflection device according to Claim 1 or 2, further
comprising:
an angle measurement means that measures an elevation angle and an
azimuth angle of the reflector unit, wherein
25 a main scope that is displaced together wi th the reflector unit can be
attached to the reflector unit .
4. The radio wave reflection device according to Claim 3, wherein the
angle measurement means is an angle scale for reading a rotat iona l angle of each
30 rotational axis of the joint unit.
5. The radio wave reflection device according to Claim 3, wherein the
angle measurement means is one of an acceleration sensor and a gyro sensor
incorporated into the reflector unit.
24
6. The radio wave reflection device according to any one of Claims 1 to 5,
wherein a scope can be attached to a rotat ing support shaft of each of the two
reflectors.
5
7. The radio wave reflection device according to any one of Claims 1 to 6,
wherein an angle scale for reading a rotational angle is placed on a rotating support
shaft of each of the two reflectors.
10 8. A method for installing a radio wave reflection device that relays , by
reflection, radio communications between a first antenna device and a second
antenna device distant from each other, the radio wave reflection device including
a mounting unit that securely mounts the radio wave reflection device on a stable
installat ion place, a reflector unit that holds two reflectors at a t ilt angle of 45º and
15 which reflectors are coaxial and rotatable independently of each other , and a joint
unit that connects the reflector unit to the mounting unit and has rotat ional
freedom along two axes orthogonal to each other , the method comprising:
measuring a direction of the firs t antenna device and a direction of the
second antenna device;
20 specifying a plane of incidence defined by the first antenna device, the
second antenna device and the radio wave reflection device;
adjusting an angle of the joint uni t so that a normal to the plane of
incidence and a rotational axis of the two reflectors coincide with each other ; and
pointing the two reflectors respectively in the direction of the first antenna
25 device and the direct ion of the second antenna device.