JPH05335828A - Antenna for satellite communication for mobile body - Google Patents

Abstract

PURPOSE:To minimize line interruption and to simplify the structure of the equipment by deciding the azimuth by the earth magnetism and controlling the directivity of the antenna by a gyro scope so as to be in a prescribed azimuth thereby setting a communication line without a delay. CONSTITUTION:A computing element 3 compares the direction of the earth magnetism measured by an azimuth sensor 1 and a travelling direction of a mobile body measured by a gyro scope 2 prior to the system operation and an obtained azimuth is adopted when rates of change in the both are coincident over a prescribed time. Then the output of the sensor 1 and the output of the scope 2 are always compared and when a rate of a change in the output of the sensor 1 is larger, the output of the scope 2 is adopted to prevent malfunction due to disturbance in the earth magnetism and mechanical vibration. Furthermore, when a difference between the rate of changes in the output of the both is a prescribed value or below, the output of the sensor 1 is adopted to correct an accumulated error of the scope 2. Finally the output of the computing element 3 controls a driver 5 to direct the directive antenna 4 in a prescribed azimuth at all times.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile satellite communication antenna used for mobile satellite communication and having a function of controlling the direction of a directional antenna.

[0002]

2. Description of the Related Art Is a conventional mobile antenna omnidirectional?
When the antenna has directivity, the antenna directivity is controlled so that the received electric field strength is maximized. In mobile satellite communication, the use of high-gain antennas is desirable for improving communication quality because the satellites are distant, but there is a limit in terms of installation space and cost.

On the other hand, since the directional antenna needs to be controlled so that the directivity of the antenna is always directed toward the satellite in accordance with the movement of a moving body such as an automobile, the directivity is set so that the electric field strength received from the antenna becomes maximum. It is generally controlled. However, if the passage of the radio wave is blocked by a tunnel or the like, the directivity cannot be controlled, so the satellite was re-acquired and communication was performed after the shield was released.

[0004]

As described above, the conventional mobile satellite communication antenna has a drawback that it takes time to reacquire satellites.

The object of the present invention is to provide a satellite communication of a mobile body which always tries to direct the directivity of the antenna to the satellite regardless of the presence or absence of radio waves from the satellite and the presence or absence of shielding of the propagation path even when the geomagnetism is disturbed. To provide an antenna.

[0006]

The antenna for mobile satellite communication according to the present invention is a directional antenna mounted on a mobile body, a direction sensor for measuring the direction by geomagnetism, and a gyroscope for measuring the traveling direction of the mobile body. And a computing unit that integrates and compares the output of the azimuth sensor and the output of the gyroscope, and a drive device that rotates a directional antenna by the output from the computing unit, and the moving body itself in the gyroscope. Of the gyroscope and the output of the azimuth sensor are compared after determining the azimuth after confirming that the direction of the geomagnetism measured by the azimuth sensor is stable. When the difference between the change rate of the output of the azimuth sensor and the change rate of the output of the gyroscope is less than or equal to a certain value, the output of the azimuth sensor is adopted, By providing the function of correcting the accumulated error Rosukopu the calculator performs mutual correction of the output of the output of the azimuth sensor gyroscope,
The directivity of the directional antenna is always oriented in a fixed direction regardless of the direction of the moving body.

[0007]

The present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention. In the embodiment shown in FIG. 1, an azimuth sensor 1 using geomagnetism, an arithmetic unit 3 for comparing the output of the azimuth sensor with the output of the gyroscope 2, and a driving device for moving the directional antenna 4 by the output from the arithmetic unit 3. 5 and.

Next, the operation of this embodiment will be described. First, before operating this system, the calculator 3 compares the direction of the geomagnetism measured using the azimuth sensor 1 with the traveling direction of the moving body measured using the gyroscope 2. As a result, when the rates of change of both agree with each other for a certain period of time, it is considered that the geomagnetism there is stable, and the value of the azimuth obtained at that time is adopted.

Thereafter, the output of the azimuth sensor 1 and the output of the gyroscope 2 are constantly compared, and the change rate of the output of the azimuth sensor 1 is compared with the change rate of the moving direction of the moving body obtained by the gyroscope 2. If it is larger, the output of the gyroscope 2 is adopted to prevent malfunction due to the disturbance of the earth's magnetism and mechanical vibration, and conversely, the change rate of the output of the azimuth sensor 1 and the change rate of the output of the gyroscope 2 are compared. When the difference is less than a certain value, the output of the azimuth sensor 1 is adopted to correct the accumulated error of the gyroscope 2. By giving the calculator 3 such a function, the output of the azimuth sensor 1 and the output of the gyroscope 2 are mutually corrected.
Finally, the drive unit 5 is moved by the output from the computing unit 3 and the directional antenna 4 is always oriented in a fixed direction.

The geostationary satellite for communication is distant from the ground by about 30,000 km, and it can be seen in a substantially constant azimuth in the range of several thousand km in which an ordinary automobile or the like moves. Therefore, if the directivity is placed in a certain direction, it is possible to capture the communication satellite within a range that is practically acceptable.

[0012]

As described above, according to the present invention, the azimuth is determined by the geomagnetism and the gyroscope is controlled so that the directivity of the antenna is directed to a fixed azimuth. Since it is not necessary, the communication path can be set without a time delay. Further, there is an effect that the disconnection due to the blocking of the communication path can be minimized.

In addition to the effect that effective communication is possible because the method of satellite acquisition by the received signal is not used even if the generation of the received signal is burst-like as in packet communication, it can be used. The effect is that the device structure can be simplified.

[Brief description of drawings]

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

[Explanation of symbols]

 1 azimuth sensor 2 gyroscope 3 arithmetic unit 4 directional antenna 5 drive device

Claims (2)

[Claims] 1. A directional antenna mounted on a mobile body,
An azimuth sensor that measures the azimuth by geomagnetism, a gyroscope that measures the traveling direction of the moving body, an arithmetic unit that integrates and compares the output of the azimuth sensor and the output of the gyroscope, and an output from the arithmetic unit It has a driving device for rotating a directional antenna, measures the traveling direction of the moving body itself with the gyroscope, and determines the azimuth after confirming that the direction of geomagnetism measured by the azimuth sensor is stable. After that, the output of the gyroscope and the output of the azimuth sensor are compared, and when the difference between the change rate of the output of the azimuth sensor and the change rate of the output of the gyroscope is less than or equal to a value, By adopting the output, by giving the arithmetic unit a function of correcting the accumulated error of the gyroscope, the output of the azimuth sensor and the gyroscope Performs mutual correction of the output of-loop, regardless of the orientation of the moving object, always mobile satellite communication antenna, characterized in that the facing is the orientation of the directional antenna in a certain azimuth. 2. When the rate of change of the output of the azimuth sensor and the rate of change of the gyroscope are significantly different, the output of the gyroscope is adopted to prevent malfunction due to disturbance of the geomagnetic field or mechanical vibration. The antenna for mobile satellite communication according to claim 1.