JPH0969719A - Tracking antenna device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tracking antenna which can be automatically reset when the correction of a gyrosensor is inaccurate. SOLUTION: The radio wave received by a planar antenna 1 is converted into an IF band by an LNB 2, and a reception detection circuit 5 detects the presence or absence of signals which are distributed by a distributor 3. If the distributed signals are confirmed, i.e., a satellite is acquired, the output of the circuit 5 is turned on. On the other hand, the output of the circuit 5 is turned off if the distributed signals are not confirmed, i.e., the satellite is not acquired. That is, the output of the circuit 5 is repetitively turned on and off if a tracking mode is not secured. This characteristic is utilized by a decision part 10 to decide that the tracking mode cannot be secured when the output of the circuit 5 is first turned on after application of a power supply and then repetitively turned on and off by the fixed frequency or more within a fixed time. Then the procedure is carried out again from the operation that is done when the power supply is applied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tracking antenna device used for receiving satellite broadcast radio waves and communication radio waves on a moving body such as an automobile.

[0002]

2. Description of the Related Art In recent years, an increasing number of mobile units (for example, trains, ships, automobiles, airplanes) are equipped with an antenna for mobile communication with a ground station or an artificial satellite station and for receiving broadcast waves. I'm doing it. In particular, with the spread of satellite broadcasting, there is an increasing need to receive satellite broadcasting on mobile units.

In order to receive a weak radio wave from a satellite like a satellite broadcast, a high-gain antenna having a sharp directivity is generally required. Therefore, when trying to receive on a moving body, it is always a radio wave source. It is necessary to track the satellite at high speed and with high accuracy, which is an expensive device. Therefore, there is a strong demand for an inexpensive tracking antenna device.

Of the several tracking methods proposed as the tracking method for the tracking antenna device, one of the most satisfying needs is the step track tracking method. This step track tracking method has a feature that the number of attached circuits is relatively small and the system is simple. Among them, especially in pursuit of low cost, there is a 1-axis step track tracking system with a fixed elevation angle.

FIG. 3 is a block diagram showing a conventional tracking antenna device, and FIG. 4 is a flow chart showing the operation of the conventional tracking antenna device. Taking the BS reception tracking antenna device of the step track tracking system with the azimuth direction of 1 axis as an example, the tracking antenna device is
A plane antenna 1 as a microwave receiving antenna from a satellite, an LNB (low noise block down converter) 2, a distributor 3, a receiving level detecting circuit 4 as a receiving level detecting means, a receiving detecting circuit 5 and a controlling means. The control circuit 6 and the azimuth direction drive motor 7 and the azimuth direction drive mechanism section 8 which form the azimuth direction drive means of the planar antenna 1. The plane antenna 1 receives the microwave signal from the satellite, and the LNB 2 converts the microwave signal received by the plane antenna 1 into an IF signal. The distributor 3 divides the IF signal converted by the LNB 2 into two parts, one of the distributed signals is sent to a receiver (not shown) as a video signal, and the other signal is sent to the reception level detection circuit 4. The reception level detection circuit 4 outputs a reception level detection signal corresponding to the strength of the reception level to the control circuit 6
To send to. The control circuit 6 sends a control signal to the azimuth direction drive motor 7 based on the value of the reception level detection signal. At this time, the reception detection circuit 5 is turned ON / OFF.
Based on the signal, it is determined whether or not the satellite is captured, and the satellite tracking mode and the satellite search mode are switched and controlled. The azimuth direction drive motor 7 is for rotating the azimuth direction drive mechanism portion 8 by a control signal from the control circuit 6 and setting the azimuth direction angle so that the planar antenna 1 faces the satellite direction.

The control circuit 6 refers to the output signal of the reception level detection circuit 4 while always swinging the flat antenna 1 to the right and left by a slight angle, and drives it in the azimuth direction so as to rotate the flat antenna 1 in the direction in which the reception level increases. It drives the means.

Further, since the step track tracking system is generally suitable only for low speed tracking, by adding a gyro sensor 9 and referring to the output of the gyro sensor 9, low speed tracking to high speed tracking are possible.

[0008]

However, in the tracking antenna device having the above-described structure, the gyro tracking mainly by the gyro sensor is dominant, and the accumulated tracking error which is a defect of the gyro tracking is detected by the step track tracking method. This is a tracking method for correction, and the accuracy of the gyro sensor 9 becomes a problem.

The correction of the accumulated tracking error of the gyro tracking by the above step track tracking method means that when the tracking antenna device is in the tracking state, the antenna itself is spatially stationary even if the moving body is in the rotating state. Because it is in a state,
As long as the peak of the reception level is captured by the step track tracking, the cumulative tracking error of the gyro can be corrected from the output at that time, and the correction value can be updated.

By the way, since the gyro sensor 9 has a drift due to temperature and the like, and this drift amount is superimposed on the output, it is necessary to detect the gyro drift amount and correct the output of the gyro sensor 9. However, since the satellite was not captured when the power was turned on, it cannot be corrected as described above.

Therefore, when the power is turned on, the moving body stands still,
Or, if the vehicle is in a straight traveling state, the drift amount can be accurately corrected, but if the moving body is in a rotating state, the error in the drift amount correction will be large, and the tracking accuracy will be greatly affected, possibly resulting in a situation where tracking cannot be performed. there were.

Here, the control state until the satellite is captured for the first time when the power is turned on and the drift correction is stabilized is called an initial capture mode, and then the stable control state is called a tracking mode.

In FIG. 4, if there is a large error in the calculation of the correction value of the gyro output when the power is turned on, the correction value is largely deviated even if the initial acquisition mode is started, and if the acquisition is not completed completely, manual operation is performed. There was a problem that it would not return forever unless the power was turned off and then turned on again.

More specifically, the gyro sensor 9 for high-speed rotation has a temperature drift in the output, and it is necessary to fetch the correction value into the CPU of the control circuit 6 in order to correct this. However, since it is not always known whether or not the moving body is moving, the correction value cannot be simply determined, and it is necessary to estimate the correction value using a filter or the like.
Therefore, since the correction value and the drift amount do not completely match in the initial acquisition mode until the satellite tracking mode in which the gyro correction is stable, the accuracy is slightly deteriorated and the satellite may not be acquired in some cases. In this case, it will not recover unless the power is turned on again manually.

The present invention has been made in view of the above points, and an object thereof is to provide a tracking antenna device capable of automatically returning when the correction of the gyro sensor is incorrect. To provide.

[0016]

According to the first aspect of the present invention,
A plane antenna provided on the mobile unit for receiving signals from the satellite, a reception level detection circuit for detecting the level of the received signal and outputting it as a reception level detection signal, and whether or not the signal from the satellite is being received. A reception detection circuit that detects whether or not the azimuth direction driving unit that rotates the planar antenna in the azimuth direction, a gyro sensor for knowing the amount of rotation of the moving body in the azimuth direction, and control that controls the azimuth direction driving unit. A gyro sensor output after the power is turned on, the drift amount of the gyro sensor output is detected after the power is turned on, and the zero point of the gyro sensor output is corrected using the drift amount as a drift correction amount. The tracking antenna device detects the satellite direction from the output of the satellite and drives the azimuth direction drive unit so that the planar antenna always faces the direction of the satellite. Then, a judgment unit for recognizing that the satellite cannot be captured due to a large correction value between the time when the power is turned on and the correction of the temperature drift of the gyro sensor is stabilized is added. When it is recognized that the correction value of the sensor has largely deviated, the drift correction amount of the gyro sensor is set again.

According to a second aspect of the present invention, in the tracking antenna apparatus according to the first aspect, the judging section is configured to switch the ON / OFF switching of the output of the reception detecting circuit at a constant cycle. It is characterized in that the correction value of the sensor is recognized to have largely deviated, and the drift correction amount of the gyro sensor is set again.

According to a third aspect of the present invention, in the tracking antenna device according to the first aspect, the judging section is configured to: when the ON / OFF switching of the output of the reception detecting circuit is more than a certain number of times within a certain time, It is characterized in that the correction value of the gyro sensor is recognized to have largely deviated, and the drift correction amount of the gyro sensor is set again.

According to a fourth aspect of the present invention, in the tracking antenna device according to the first aspect, the determining section determines that the output from the reception level detecting circuit is unstable and fluctuates,
It is characterized in that the correction value of the gyro sensor is recognized to have largely deviated, and the drift correction amount of the gyro sensor is set again.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the overall configuration of a tracking antenna device according to an embodiment of the present invention. In the tracking antenna device according to the present embodiment, for convenience of description, the same parts as those shown in FIG. 3 as a conventional example are designated by the same reference numerals and the description thereof will be omitted. The determination unit 10 recognizes that the satellite cannot be captured because the correction value of the gyro sensor 9 is largely deviated in the initial capture mode. It should be noted that the judgment unit 10 turns on / off the reception level detection signal output from the reception level detection circuit 4.
When OFF switching is repeated at a constant cycle, when ON / OFF switching of the reception level detection signal is repeated a certain number of times or more within a constant time, or when the output from the reception level detection circuit 4 is unstable and fluctuates. If the correction value of the gyro sensor 9 is deviated, the correction value is recognized.

The operation of this embodiment will be described below with reference to the drawings. FIG. 2 is a flowchart showing the operation according to this embodiment. In the present embodiment,
As a method for the determination unit 10 to recognize the deviation of the correction value of the gyro sensor 9, the case where the ON / OFF switching of the reception level detection signal is performed a certain number of times or more within a certain time will be described.

The feature of this embodiment lies in that the satellite acquisition completion is further confirmed in the conventional example.
Here, the correction value of the gyro sensor 9 is different from the state in which the satellite acquisition is not completed in the initial acquisition mode, and even if the satellite is acquired once, the planar antenna 1 rotates in the azimuth direction and cannot be received. The phenomenon is that the tracking mode is not set. In the present embodiment, the radio wave received by the plane antenna 1 is converted into the IF band by the LNB 2 and the presence or absence of a signal after being distributed by the distributor 3 is detected by the reception detection circuit 5, and when this signal is present, that is, the satellite. The output of the reception detection circuit 5 is ON when the signal is being captured, and the output of the reception detection circuit 5 is OFF when there is no signal after distribution, that is, when the satellite is not captured. In other words, the output of the reception detection circuit 5 is ON / O when the tracking mode cannot be entered.
Since FF will be repeated, use this characteristic,
For example, in the determination unit 10, the output of the reception detection circuit 5 is first turned on after the power is turned on, and then the output is turned on within 10 seconds.
When N / OFF is repeated twice or more, it is recognized that the tracking mode cannot be entered, and the operation at power-on is restarted.

Therefore, according to this embodiment, when the error in the correction value of the gyro sensor 9 is large, the power is manually turned on.
It can be automatically restored without turning it off.

Although the plane antenna 1 rotates in the azimuth direction to capture the satellite, the reception detection circuit 5 repeats ON / OFF during the rotation, and the judgment unit 10 recognizes this. Then, the drift correction amount of the gyro sensor 9 may be set again after the power is turned on, and the determination unit 10 recognizes that the output from the reception level detection circuit 4 is unstable and fluctuates. If the drift correction amount of the gyro sensor 9 is set again after the power is turned on, the deviation of the correction value of the gyro sensor 9 can be determined more accurately.

[0025]

According to the first aspect of the present invention, a plane antenna for receiving a signal from a satellite, which is provided in a moving body, and a reception level detecting circuit for detecting the level of the received signal and outputting it as a reception level detection signal are provided. , A reception detection circuit that detects whether or not a signal from a satellite is being received, an azimuth direction drive unit that rotates the planar antenna in the azimuth direction, and a gyroscope for knowing the rotation amount of the moving body in the azimuth direction. It is composed of a sensor and a control circuit that controls the azimuth direction drive unit.After the power is turned on, the drift amount of the gyro sensor output is detected to correct the zero point of the gyro sensor output, and the gyro sensor output and reception level after this correction are performed. In the tracking antenna device that detects the direction of the satellite from the output of the detection circuit and drives the azimuth direction drive unit so that the planar antenna always faces the direction of the satellite, By adding a judgment unit that recognizes that the satellite could not be captured due to a large correction value until the temperature drift correction of the gyro sensor became stable, the correction value of the gyro sensor greatly changed by the judgment unit. When the error is recognized, the drift correction amount of the gyro sensor is set again, so if the error in the correction value of the gyro sensor is large, turn the power on / off manually.
Therefore, it is possible to provide a tracking antenna device capable of automatically returning when the correction of the gyro sensor is incorrect.

According to a second aspect of the present invention, in the tracking antenna device according to the first aspect, the determination unit is such that when the ON / OFF switching of the reception level detection signal is repeated at a constant cycle, the correction value of the gyro sensor is set. Is recognized as a large deviation, and the drift correction amount of the gyro sensor is set again. Therefore, when the error in the correction value of the gyro sensor is large, there is no need to manually turn the power on / off, If the correction is incorrect, it can be automatically restored.

According to a third aspect of the present invention, in the tracking antenna device according to the first aspect, the determination unit is configured to detect the gyro sensor when the ON / OFF switching of the reception level detection signal is more than a certain number of times within a certain period of time. Since it is recognized that the correction value has largely deviated and the drift correction amount of the gyro sensor is set again, the deviation of the correction value of the gyro sensor can be recognized within a certain period of time, so it is possible to make a judgment faster. it can.

According to a fourth aspect of the present invention, in the tracking antenna device according to the first aspect, when the output from the reception level detecting circuit is unstable and fluctuates, the drift correction amount of the gyro sensor is set again. Therefore, the deviation of the correction value of the gyro sensor can be determined more accurately.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of a tracking antenna device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing an operation of the tracking antenna device according to the present embodiment.

FIG. 3 is a block diagram showing a tracking antenna device according to a conventional example.

FIG. 4 is a flowchart showing an operation of a tracking antenna device according to a conventional example.

[Explanation of symbols]

 1 Planar Antenna 2 LNB 3 Distributor 4 Reception Level Detection Circuit 5 Reception Detection Circuit 6 Control Circuit 7 Azimuth Direction Drive Motor 8 Azimuth Direction Drive Mechanism Section 9 Gyro Sensor 10 Judgment Section

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[Procedure amendment]

[Submission date] October 16, 1995

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Figure 2

[Correction method] Change

[Correction contents]

[Fig. 2]

[Procedure amendment 2]

[Document name to be amended] Drawing

[Correction target item name] Fig. 4

[Correction method] Change

[Correction contents]

FIG. 4

Claims (4)

[Claims] 1. A plane antenna for receiving a signal from a satellite, which is provided in a mobile body, a reception level detection circuit for detecting the level of the received signal and outputting it as a reception level detection signal, and a signal from the satellite. A reception detection circuit for detecting whether or not it is in the middle, an azimuth direction drive unit for rotating the planar antenna in the azimuth direction, a gyro sensor for knowing the rotation amount of the moving body in the azimuth direction, and the azimuth direction drive unit. And a control circuit for controlling the gyro sensor output after the power is turned on to detect the drift amount of the gyro sensor output and correct the zero point of the gyro sensor output by using the drift amount as a drift correction amount. A tracking amplifier that detects the direction of the satellite from the output of the reception level detection circuit and drives the azimuth direction drive unit to always face the planar antenna in the direction of the satellite. In the tenor device, a judgment unit for recognizing that the satellite cannot be captured due to a large correction value between when the power is turned on and when the correction of the temperature drift of the gyro sensor is stabilized is added. A tracking antenna device, wherein when it is recognized that the correction value of the gyro sensor has largely deviated, the drift correction amount of the gyro sensor is set again. 2. The determination unit recognizes that the correction value of the gyro sensor has largely deviated when the ON / OFF switching of the output of the reception detection circuit is repeated in a constant cycle, and the gyro sensor The tracking antenna device according to claim 1, wherein the drift correction amount is set again. 3. The gyroscope recognizes that the correction value of the gyro sensor has largely deviated when the ON / OFF switching of the output of the reception detection circuit is more than a certain number of times within a certain time, 2. The drift correction amount of the sensor is set again.
The tracking antenna device described. 4. The determination unit recognizes that the correction value of the gyro sensor is largely deviated when the output from the reception level detection circuit is unstable and fluctuates, and the drift correction amount of the gyro sensor is detected. 2. The tracking antenna device according to claim 1, wherein the setting is repeated.