JP3306758B2 - Satellite broadcasting mobile receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a satellite broadcasting mobile receiving apparatus for satisfactorily receiving radio waves from satellite broadcasting during flight.

[0002]

2. Description of the Related Art Some devices related to the reception of image information of a satellite broadcast while moving are already developed in trains, ships, buses, small passenger cars and the like, and some of them are in a practical stage. However, devices relating to the reception of satellite broadcast image information during the flight of an aircraft have different technical requirements.

[0003]

SUMMARY OF THE INVENTION A satellite broadcast receiver for an aircraft is required to be miniaturized due to restrictions on installation locations and the need to minimize the influence on the aircraft during flight. Also, since it is mounted on the surface of the body of an aircraft, it is often used in places where environmental conditions are severe, such as changes in external atmospheric pressure or wide-range temperature changes. Further, in order to protect the apparatus from wind pressure during flight, parts including active elements should be installed in a pressurized room having a good operating environment as much as possible. Further, it is required to improve the tracking performance of the antenna.

[0004]

SUMMARY OF THE INVENTION In order to solve the above problems, a satellite broadcast mobile receiving apparatus according to the present invention is provided. Therefore, in the present invention, the conventional satellite broadcasting mobile receiving device is divided into a plurality of devices, and each of the divided devices is reduced in size and weight as much as possible so that it can be installed in a radome used in an aircraft. ing. The antennas of multiple mobile satellite broadcast receivers installed in the radome are:
In the prior art, since the tracking sensor output added to the antenna is used to direct the satellite broadcast, the device is divided and the tracking circuits are required by the number of divisions. By using the navigation data output from the aircraft, the antenna of each device can be directed to the broadcast satellite with a simple circuit regardless of the number of divisions of the device. In addition, a metal piece adhered to the radome surface to obtain a lightning storm effect greatly affects the transmission characteristics of radio waves in relation to the antenna installed in the radome, but multiple antennas are arranged in the radome As a result, any of the antennas in the radome can always receive the broadcast satellite radio wave at a high level with respect to the incoming radio waves in all directions, and the antenna output is mounted on the aircraft of the present invention by combining a plurality of antenna outputs. The satellite broadcast mobile receiver can stably receive the radio waves of the broadcast satellite in all attitude states of the aircraft.

[0005]

An embodiment of the present invention will be described below with reference to the drawings. This satellite broadcast mobile receiver includes a radome 1 made of FRP, and an antenna 3 having directivity such as an array antenna, a phased array antenna, a parabolic antenna, and the like.
Inertial navigation device 5 that outputs navigation data during flight, control unit 7 that obtains a control signal for controlling the directional direction of antenna 3 by navigation data, and controls antenna 3 toward a broadcast satellite by a control signal from control unit 7. It comprises a driving unit 9 for directing and a signal synthesizing unit 11 for in-phase synthesizing the output of the signal received by the antenna 3. Signal synthesis unit 11
Synthesizes the output of the intermediate frequency from each antenna in phase. The antenna 3 is a rectangular planar antenna having a size of about 15 cm × about 40 cm. One side of the dielectric substrate is a ground plane, and the other side has a structure in which about 200 radiating elements are regularly arranged. I have. Since the present invention is premised on the use in high altitudes where the atmospheric pressure is reduced to one-fourth above the ground, the antenna substrate material is made of polyethylene and air, which provide high gain and are not damaged even when depressurized. A composite rigid substrate or a composite substrate material of polytetrafluoroethylene and glass fiber is used.

[0006] The inertial navigation device 5 uses automatic estimation navigation,
It is a device that determines the position and attitude of an airplane, and calculates the traveling direction, pitch angle, roll angle, altitude, latitude, and longitude data of the aircraft along with other data necessary for the operation of the aircraft.
It is generated by a 32-bit digital signal specified by the EEC (Avionics Industry Commission). For example, the digital signal in FIG. 4 represents the current latitude of the aircraft.
This bit sequence is continuously output for other data according to a certain rule, and the control unit 7 first detects only the bit sequence of the data relating to the attitude, altitude, and position required for the present invention. The type of information is defined by a label represented by the first 8 bits (bit 1 to bit 8) of the bit string, and the first 8 bits' 1100100 in FIG.
0 ′ represents the label 310. If such a bit is set, the control unit 7 detects this bit string as latitude data. If the first 8 bits are '110010
If it is 01 ', it becomes a label 311 and is detected as latitude data. Other data is similarly detected. After detecting the bit sequence of the data necessary for the antenna control by the label, the control unit 7 generates specific data from the bit sequence of bit 9 and thereafter. This data and RO
A processing signal written in M (read only memory) generates a control signal for directing the antenna 3 toward the broadcast satellite. The drive unit 9 sets the antenna 3 to 0.
It is driven in units of 1 °, and without such accuracy, it cannot receive radio waves from broadcast satellites. Further, the control unit 7, the driving unit 9, the signal synthesizing unit 11, the tuner 13, and the monitor 19 are housed in the body of an airplane in a pressurized room as shown in FIG. Then, only the antenna 3 is installed outside the body, and is covered with the radome 1.

FIG. 2 and FIG. 3 show an example of a configuration in which a plurality of divided antennas are housed in a radome 1 on the fuselage of an aircraft. The example of arrangement is shown. A lightning arrester 15 is adhered to the wall of the radome 1. The lightning arrester 15 may be a metal strip or a rod.
Alternatively, a metal disk may be provided so as to be appropriately arranged. In order to reduce the influence of radio wave interference on the antenna 3 by the lightning arrester 15, the antenna 3 is arranged as far away from the lightning arrester 15 as possible. The two antennas 3 are mounted on a turntable 17, respectively. The rotation angle Ф of the turntable 17 and the inclination angle θ of the antenna 3 are controlled by the control unit 7 and the drive unit 9 shown in FIG. And the two antennas 3 are controlled so as to always face the broadcast satellite regardless of the attitude. The antenna 3 is not particularly limited as long as it can receive satellite broadcasting, but a planar antenna is preferable in consideration of miniaturization. During the flight, the temperature inside and outside the radome is almost the same, and the temperature difference is extremely large. Therefore, as a material used for the mechanical parts of the antenna, polytetrafluoroethylene (heat-resistant temperature: 260 ° C. to −270 ° C.) that can withstand not only high temperature but also low temperature is preferable.

FIGS. 5 to 8 show radio waves when the antenna is arranged in the radome to which the lightning arrester is adhered as shown in FIGS. 2 and 3 and the azimuth of the antenna 3 is changed by 22.5 °. It is a result of measuring transmission characteristics. The C / N ratio received by one antenna when the lightning arrester was not covered by the radome to which it was bonded was 11 dB. In this case, the radio wave direction with respect to the radome is a direction as shown in FIG. For example, when a radio wave is incident from the front of the radome, the antenna is driven and controlled so as to face the directions of FIGS. 2 and 3. This corresponds to the case where the angle of the measurement result is 0 °. As can be seen from the tables in FIGS. 5 and 6, the reception C / N ratio of the antenna installed in front of the radome is 9.5 dB, and the reception C / N ratio of the antenna installed in the rear is 8.
It was 75 dB. Radome and lightning arrester 1 for front installation
Due to the influence of No. 5, the reception C / N ratio is deteriorated by 1.5 dB as compared with the reception C / N ratio when the radome is not attached. In the rear installation, it is further affected by the two lightning arresters installed between the antennas and deteriorates by 2.25 dB compared to the reception C / N ratio when the radome is not attached. Thus, the reception C / N ratio of the front installation and the rear installation differs depending on the incident angle of the radio wave,
It can be seen that combining the antenna gain pie charts of FIGS. 7 and 8 results in a uniform antenna gain in almost all directions. That is, the output becomes substantially constant by combining the received signals from the two antennas. By demodulating the image signal with the tuner 13 and selecting a channel, a satellite broadcast can be viewed on the monitor 19. FIG. 10 and FIG.
Reference numeral 1 denotes a place where the radome is installed on an aircraft.

[0009]

As described above, according to the present invention, by using the navigation data output from the inertial navigation device,
Regardless of the number of devices, each antenna can be directed to the broadcast satellite with a simple circuit. In addition, the lightning arrester adhered to the surface of the radome greatly affects the transmission characteristics of radio waves due to the positional relationship with the antenna installed in the radome. By combining the radio waves in phase, the radio waves of the broadcasting satellite can be always received at a high level. Therefore, it has become possible to stably receive the radio wave of the broadcasting satellite in all attitudes of the aircraft.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram of an embodiment of the present invention.

FIG. 2 is a plan view of an antenna installed in a radome according to one embodiment of the present invention.

FIG. 3 is a side view of an antenna installed in a radome according to one embodiment of the present invention.

FIG. 4 shows 32-bit digital signal data representing the latitude of an aircraft used for antenna control according to the present invention.

FIG. 5 is a table of radio wave transmission characteristics measured by an antenna installed in front of a radome according to one embodiment of the present invention.

FIG. 6 is a table of radio wave transmission characteristics measured by an antenna installed behind a radome according to one embodiment of the present invention;

FIG. 7 is a pie chart of a radio wave transmission characteristic measured by an antenna installed in front of a radome according to one embodiment of the present invention;

FIG. 8 is a pie chart of a radio wave transmission characteristic measured by an antenna installed behind a radome according to one embodiment of the present invention;

FIG. 9 is a diagram showing a radio wave receiving direction according to an embodiment of the present invention.

FIG. 10 is a diagram showing an installation location of a radome according to an embodiment of the present invention.

FIG. 11 is a diagram showing a setting place of a radome according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Radome 3 Antenna 5 Inertial navigation device 7 Control part 9 Drive part 11 Signal synthesis part 13 Tuner 15 Lightning arrester 17 Turntable 19 Monitor

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Osamu Ono 1-6-5 Haneda Airport, Ota-ku, Tokyo (72) Inventor Hisayoshi Nakamura 1-6-5 Haneda Airport, Ota-ku, Tokyo (56) References Special JP-A-54-29500 (JP, A) JP-A-59-189730 (JP, A) JP-A-3-1712 (JP, A) JP-A-3-66211 (JP, U) (58) Fields investigated ( Int.Cl. ⁷ , DB name) H01Q 1/00-1/10 H01Q 1/27-1/52 H01Q 3/00-3/46 H01Q 21/00-21/30

Claims (1)

(57) [Claims] 1. An antenna means comprising a plurality of antennas having directivity, a navigation device for generating a navigation signal representing the position and attitude of an aircraft, a navigation signal from the navigation device and a position of a broadcasting satellite stored in advance. A control unit for generating a control signal for controlling the antenna means from information representing the
Driving means for driving the antenna means in response to the control signal to direct the directional direction of the antenna means to the position of the broadcast satellite; in-phase combining means for in-phase combining outputs from a plurality of antennas having the directivity; A radome covering the antenna means in the longitudinal direction in which a plurality of antennas having directivity are arranged, and a metal piece oriented in the longitudinal direction on the radome for the plurality of antennas having directivity, and a gap in the longitudinal direction. A plurality of metal pieces oriented in the transverse direction along the radome for each of the plurality of antennas having the directivity intersecting with the metal pieces oriented in the longitudinal direction and the plurality of antennas having the directivity are provided. A mobile satellite broadcast receiving apparatus for receiving a satellite broadcast including an image signal, comprising an arrester having a metal piece oriented in the short direction and a metal piece oriented in parallel between antennas.