Communications: directive radio wave systems and devices (e.g. – Return signal controls radar system – Antenna control
Reexamination Certificate
2001-11-05
2003-04-29
Gregory, Bernarr E. (Department: 3662)
Communications: directive radio wave systems and devices (e.g.,
Return signal controls radar system
Antenna control
C342S074000, C342S175000, C343S757000, C343S762000, C343S763000, C343S766000
Reexamination Certificate
active
06556165
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an antenna apparatus that is mounted on a moving body such as an airplane for microwave communication with a communication satellite or the like, as well as to a waveguide rotary coupler used in such an antenna apparatus.
2. Description of the Related Art
FIG. 10
is a block diagram showing the configuration of a conventional antenna apparatus. In
FIG. 10
, reference numeral
1
denotes a movable part and reference numeral
2
denotes a fixed part that supports the movable part
1
in a moving body such as an airplane or a vehicle that is mounted with an antenna. The movable part
1
is provided with an antenna
3
for microwave communication with a communication satellite, a ground base station, or the like, an EL motor
4
for rotating the antenna
3
about the EL (elevation) axis, and an AZ motor
5
for rotating the antenna
3
about the AZ (azimuth) axis. The movable part
1
is also provided with an EL angle detector
6
for detecting the EL angle of the antenna
3
, an AZ angle detector
7
for detecting the AZ angle of the antenna
3
, and an antenna control section
8
for controlling the EL motor
4
, the AZ motor
5
, the EL angle detector
6
, and the AZ angle detector
7
. The antenna control section
8
is provided with a drive control section
9
for driving the EL motor
4
and the AZ motor
5
and a position detecting section
10
for reading antenna angles detected by the EL angle detector
6
and the AZ angle detector
7
and for outputting the antenna angles thus read to the drive control section
9
.
In the fixed part
2
, reference numeral
11
denotes a transceiver for generating a radio signal to be output from the antenna
3
and for frequency-converting a reception signal that is supplied from the antenna
3
and performing signal processing on a resulting signal. Reference numeral
12
denotes an attitude information detecting section for detecting the attitude of the moving body such as an airplane or a vehicle that is mounted with the antenna
3
. For example, the attitude detecting section
12
detects attitudes of the moving body about the roll axis, the yawing axis, and the pitch axis and a latitude and longitude. Reference numeral
13
denotes a drive instruction generating section for converting attitude information obtained by the attitude detecting section
12
into information suitable for a coordinate system that is employed in the antenna control section
8
and for generating a drive instruction for a motor drive control. Reference numeral
14
denotes an AC power source of the movable part
1
and the fixed part
2
, and reference numeral
15
denotes an AC/DC converter for converting an AC output of the AC power source
14
into DC power.
Reference numeral
16
denotes a waveguide rotary coupler that is provided between the movable part
1
and the fixed part
2
to transmit a radio output signal from the transceiver
11
to the antenna
3
and to transmit a reception signal from the antenna
3
to the transceiver
11
. Reference numeral
17
denotes a slip ring that is provided between the movable part
1
and the fixed part
2
to transmit a drive instruction signal from the drive instruction generating section
13
to the drive control section
9
. Reference numeral
18
denotes a slip ring that is provided between the movable part
1
and the fixed part
2
to transmit DC power produced by the AC/DC converter
15
to the antenna control section
8
.
The operation of the above conventional antenna apparatus will be described below. The directivity of an antenna that is mounted on a moving body varies depending on the attitude of the moving body. The conventional antenna apparatus of
FIG. 10
has the EL motor
4
and the AZ motor
5
for driving the antenna
3
about the EL axis and the AZ axis, respectively. A result of driving of the antenna
3
by the motors
4
and
5
is detected as antenna angles by the EL angle detector
6
and the AZ angle detector
7
, read by the position detector
10
, and then input to the drive control section
9
. On the other hand, latitude/longitude information and attitude information of the moving body are obtained by the attitude detecting section
12
. In many cases, as in this antenna apparatus, the attitude information of a moving body is represented by a roll coordinate, a pitch coordinate, and a yawing coordinate. The attitude information of the moving body concerned is coordinate-converted by the drive instruction generating section
13
into information suitable for the EL/AZ coordinate system that is employed in the drive control section
9
, and the converted information is output to the drive control section
9
as a drive instruction. The drive control section
9
calculates a direction to which the antenna
3
should be directed based on the latitude/longitude information of the moving body and position information of a counterpart station such as a communication satellite, and drives the EL motor
4
and the AZ motor
5
after compensating the calculated direction for the attitude information of the moving body, that is, angular variations of the antenna
3
that are caused by a variation in its attitude.
For exchange of signals between the movable part
1
and the fixed part
2
, the conventional antenna apparatus uses transmission parts such as the waveguide rotary coupler
16
and the slip rings
17
and
18
. It is necessary to transmit a radio signal from the transceiver
11
to the antenna
3
and to transmit a reception signal from the antenna
3
to the transceiver
11
. For transmission of a radio signal, a waveguide, which is high in transmission efficiency, may be used depending on the frequency band. In this antenna apparatus, the waveguide rotary coupler
16
is used between the movable part
1
and the fixed part
2
. The waveguide rotary coupler
16
, which is a waveguide coupler capable of rotation about a single axis, is disposed on the AZ axis as usual. That is, the movable part
1
is supported by the fixed part
2
in such a manner as to be able to rotate about the AZ axis and the waveguide rotary coupler
16
is disposed on the AZ axis. The slip rings
17
and
18
for transmitting attitude information and power, respectively, is disposed between the movable part
1
and the fixed part
2
on the same axis (i.e., the AZ axis) as the waveguide rotary coupler
16
is. The waveguide rotary coupler
16
and the slip rings
17
and
18
can transmit a radio output signal, attitude information, and power, respectively.
Although in the configuration of
FIG. 10
the AZ motor
5
and the AZ angle detector
7
are provided in the movable part
1
, they may be provided in the fixed part
2
. In the latter case, the AZ motor
5
that is provided in the fixed part
2
rotates the movable part
1
about the AZ axis. Also in this case, it is necessary to transmit a radio output signal, attitude information, and power from the fixed part
2
to the movable part
1
via the waveguide rotary coupler
16
and the slip rings
17
and
18
, respectively, that are disposed on the AZ axis.
The conventional antenna apparatus is configured in such a manner as to use the slip rings
17
and
18
to transmit attitude information and power, respectively, from the fixed part
2
to the movable part
1
. Each of the slip rings
17
and
18
has a structure that a brush that is provided on a rotary shaft of one of the fixed side and the movable side is in contact with a ring-like electrode that is provided on a rotary shaft of the other, and hence is an electric part in which abrasion occurs between the brush and the ring-like electrode. Whereas communication equipment to be used in airplanes, ships, etc. are in many cases required to be highly reliably, the conventional antenna apparatus has a problem that the slip rings
17
and
18
used therein lower the reliability. That is, the slip rings
17
and
18
are a factor of causing such a failure as impairs signal transmission, because abrasion or dew cond
Fukushima Tomoaki
Iida Akio
Konishi Yoshihiko
Shirokawa Ichiro
Yamauchi Hidetaka
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