JPH0758536A - Method and device for tracking satellite by mobile antenna - Google Patents

Abstract

PURPOSE:To provide a method and device for tracking a satellite by a mobile antenna in which the mobile antenna is set to a direction where reception signal strength is a maximum in a short time. CONSTITUTION:Cross reference data between a difference of reception strength when a mobile antenna 1 is turned by a unit angle and a deviation in the direction of the antenna 1 with respect to a direction maximizing the reception strength are stored in advance in a memory table, and when the difference from the reception strength before and after the turning through the turning of the mobile antenna 1 actually by a unit angle is calculated, the turning angle of the antenna 1 required to maximize the reception strength is decided based on the cross reference data and the antenna 1 is driven by the decided turning angle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a satellite tracking method for a mobile antenna which is installed in a transportation means such as an automobile and receives a signal transmitted from a communication satellite or a broadcasting satellite, and a satellite tracking method using the mobile antenna. With the device.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram schematically showing the control relationship of a conventional vehicle-mounted satellite tracking device, and FIG. 4 is a flowchart showing the satellite acquisition / tracking operation of the conventional example.

As shown in FIG. 3, a conventional vehicle-mounted satellite tracking device has a mobile antenna 1 having a vertical axis and whose azimuth can be changed, and a drive device 2 for rotationally driving the mobile antenna 1 stepwise. A control device 3 for controlling the drive device 2, a receiver 4 to which a high frequency signal received by the mobile antenna 1 is supplied, and a reception intensity of a voltage or the like proportional to the intensity of the high frequency signal from the receiver 4. Computing device 5 to which information is supplied
And a level memory 6 connected to the arithmetic unit 5. That is, the receiver 4 has a built-in detection unit for detecting the reception intensity of the high-frequency signal supplied from the mobile antenna 1, and the detected value indicates the mobile antenna 1 at a predetermined unit angle (step angle). It is supplied to the arithmetic unit 5 that compares the magnitude of the reception intensity before and after the rotation when it is rotated, and to the level memory 6 that can temporarily store data and can read it as needed. Then, the calculation result of the calculation device 5 is output to the control device 3, and the drive device 2 is controlled based on the calculation result.

Next, in the above-described conventional vehicle-mounted satellite tracking device, an operation for pointing the mobile antenna 1 to a desired azimuth angle at which the reception intensity becomes maximum will be described with reference to FIG.

Now, the control device 3 controls the mobile antenna 1
If the rotation drive direction of is set to the clockwise direction (procedure 1), in this state, the reception strength as the initial value is first detected (procedure 2), and the detected value is compared to the reception strength for comparison. It is temporarily stored in the level memory 6 as Lm (procedure 3). Next, the mobile antenna 1 is rotated by a predetermined unit angle, that is, one step in the set rotational drive direction (procedure 4), and the reception intensity L after rotation is detected (procedure 5), and the detected value L And the detected value Lm read from the level memory 6 before one step rotation are compared by the arithmetic unit 5 (procedure 6). And the comparison result is L
If> Lm, it can be determined that the mobile antenna 1 has approached the desired azimuth by rotating the mobile antenna 1. Therefore, L is set as a new comparison reception intensity Lm without changing the rotational driving direction of the mobile antenna 1. After temporary storage in the memory 6 (procedure 7), the procedure returns to the procedure 4 and the moving antenna 1 is rotated one step in the same direction as the previous time, that is, in the clockwise direction. On the other hand, in step 6, the comparison result is L ≦ Lm
In this case, it is possible to determine that the mobile antenna 1 is moving away from the desired azimuth even if the mobile antenna 1 is rotated.
A signal for setting the rotation driving direction of the reverse direction to that of the previous time is output from the arithmetic unit 5 to the control unit 3 (procedure 8),
Further, L is temporarily stored in the level memory 6 as a new comparison reception intensity Lm (procedure 9), and then the procedure 4
Then, the mobile antenna 1 is rotated one step in the direction opposite to the previous one, that is, in the counterclockwise direction. After that, step 4 →
When the operation of 5 → 6 → 7 → 4 or procedure 4 → 5 → 6 → 8 → 9 → 4 is repeated several times, the mobile antenna 1 gradually turns to a desired azimuth angle at which the reception intensity becomes maximum. Become. When the desired azimuth angle is closest, steps 4 → 5 →
The operations of 6 → 8 → 9 → 4 → 5 → 6 → 7 → 4 are repeated.

Even if the rotational driving direction of the mobile antenna 1 is set to the counterclockwise direction in the above procedure 1,
It goes without saying that the operating principle is the same.

[0007]

However, the above-mentioned conventional technique adopts the step track method of rotating the mobile antenna 1 by a unit angle and comparing the reception intensity before and after the rotation each time to determine the rotation drive direction. Therefore, it is not possible to instantly direct the antenna 1 to the azimuth angle at which the reception intensity is maximum, and in particular, the mobile antenna 1
There was a problem that when a vehicle equipped with a car drastically changed its traveling direction in a short time due to a sharp curve, communication and broadcasting were interrupted because it took time to capture and track satellites.

The present invention has been made in view of the above problems of the prior art. A first object of the present invention is to provide a mobile antenna satellite capable of setting the mobile antenna in the direction in which the reception intensity is maximum in a short time. It is an object of the present invention to provide a tracking method, and a second object of the present invention is to provide a satellite tracking device suitable for implementing such a satellite tracking method.

[0009]

The first object of the present invention described above is that the degree of change in the reception intensity before and after rotation obtained when the mobile antenna is rotated by a predetermined unit angle and the reception intensity is the maximum. If the data for comparison corresponding to the deviation of the orientation of the antenna with respect to the different direction is stored in advance and the degree of change in the reception intensity before and after the rotation is calculated by actually rotating the mobile antenna by a unit angle, It is achieved by determining the rotation angle of the antenna required for maximizing the value based on the control data, and rotationally driving the antenna by the rotation angle thus determined.

A second object of the present invention described above is to provide a mobile antenna whose azimuth angle can be changed, a driving unit for rotationally driving the antenna, a control unit for controlling the driving unit, and the antenna for receiving. In the satellite tracking device having a detection unit that detects the reception intensity of the received signal and a temporary storage unit that temporarily stores the reception intensity of the antenna detected by this detection unit, the mobile antenna is rotated by a unit angle. A mobile data unit is provided with a comparison data storage unit that stores in advance the degree of change in reception intensity before and after rotation, which is associated with the deviation of the orientation of the antenna with respect to the direction in which the reception intensity is maximum. When the antenna is rotated by an angle, the degree of change in the reception intensity before and after the rotation of the antenna is calculated, and the deviation of the orientation of the antenna corresponding to this calculated value is calculated from the reference data storage unit. Out look, a signal for giving a rotation angle corresponding to the deviation of the orientation to the antenna is achieved by providing an arithmetic unit for outputting to the control unit.

[0011]

As shown in FIG. 5, the relationship between the direction of the mobile antenna with respect to the direction of the satellite and the received intensity is as follows. Since a characteristic curve that can be approximated by the nth power of cosA is shown, the degree of change in reception intensity before and after rotation obtained when the mobile antenna is rotated by a unit angle (for example, ratio or difference) and the orientation of the antenna immediately after rotation are shown. The shift A can be associated in advance. Therefore, if this correspondence is stored as the control data, the deviation of the direction of the mobile antenna from the degree of change in the reception intensity when the mobile antenna is actually rotated by a unit angle, that is, the required remaining rotation angle By rotating the antenna by the rotation angle thus determined, the antenna can be oriented in the direction in which the reception intensity is maximum in a short time.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. Here, FIG. 1 is a block diagram schematically showing the control relationship of the vehicle-mounted satellite tracking device according to the present embodiment, and FIG. 2 is a flowchart showing the satellite acquisition / tracking operation of the same embodiment. 3 corresponding to those used in FIG.

The on-vehicle satellite tracking device shown in FIG. 1 is largely different from the conventional example in that the function of the arithmetic unit 5 and the addition of the memory table 7 in which the comparison data is stored in advance are added. Reference numeral 5 is adapted to calculate the difference between the reception intensities before and after rotation so that necessary information can be read from the control data. That is, this satellite tracking device has a mobile antenna 1 that has a vertical axis and whose azimuth angle can be changed, a drive device 2 that rotationally drives this mobile antenna 1 in stages, and a drive device 2 for controlling this drive device 2. The control unit 3, the receiver 4 to which the high frequency signal received by the mobile antenna 1 is supplied, and the arithmetic unit 5 to which the detection unit of the receiver 4 receives the reception intensity information such as the voltage proportional to the intensity of the high frequency signal. And a level memory 6 which is connected to the arithmetic unit 5 and which can temporarily store data and can be read out as necessary, and a memory table 7 which is connected to the arithmetic unit 5 and from which comparison data can be read out. I have it. Then, when the mobile antenna 1 is rotated about a vertical axis by a predetermined unit angle (step angle), the arithmetic unit 5 calculates the difference between the reception intensities before and after the rotation while referring to the data in the level memory 6. The deviation of the orientation of the antenna 1 corresponding to this calculated value is read from the comparison data in the memory table 7, and a signal for giving the antenna 1 a rotation angle corresponding to this deviation of the orientation is output to the control device 3. It is supposed to do.

That is, in the memory table 7, the difference between the reception intensities before and after the rotation obtained when the mobile antenna 1 is rotated by a unit angle around the vertical axis, and the specific azimuth angle at which the reception intensity becomes maximum. Since the comparison data created by associating with the deviation of the orientation of the antenna 1 is stored, if the mobile antenna 1 is actually rotated by a unit angle and the difference in the reception intensity before and after the rotation is calculated, the calculated value is obtained. Is compared with the control data, it is possible to determine the deviation of the orientation of the antenna 1, that is, the required remaining rotation angle.

A high-frequency circuit and a baseband circuit are built in the receiver 4, and the reception intensity is generally detected by detecting the received high-frequency signal. It is also possible to substitute by the CN ratio or the like. The reception intensity information input to the arithmetic unit 5 may be an analog value or a digital value.

Next, the operation for pointing the mobile antenna 1 to a desired azimuth angle that maximizes the reception intensity in the above-described vehicle-mounted satellite tracking device will be described with reference to FIG.

Now, the control device 3 controls the mobile antenna 1
If the rotation drive direction of is set to the clockwise direction (procedure 1), in this state, the reception strength as the initial value is first detected (procedure 2), and the detected value is compared to the reception strength for comparison. It is temporarily stored in the level memory 6 as Lm (procedure 3). Next, the mobile antenna 1 is rotated by a predetermined unit angle, that is, one step in the set rotational drive direction (procedure 4), and the reception intensity L after rotation is detected (procedure 5), and the detected value L Then, the reception intensity difference B (= L−Lm) from the detection value Lm before being rotated by one step read from the level memory 6 is calculated by the arithmetic unit 5 (procedure 6). Further, the arithmetic unit 5 reads the deviation of the orientation of the mobile antenna 1 corresponding to the reception intensity difference B from the reference data in the memory table 7 (procedure 7), and moves the rotation angle corresponding to the deviation of this orientation. A signal to be given to the antenna 1 is output to the control device 3, and the moving antenna 1 is rotationally driven by the given rotation angle (procedure 8) so as to face the desired azimuth angle.

Before moving from the procedure 7 to the procedure 8, a procedure for determining the rotational driving direction depending on which side the mobile antenna 1 is largely deviated from the desired azimuth angle may be added. . In addition, the mobile antenna 1
It goes without saying that the rotation drive direction of may be set in the counterclockwise direction.

As described above, in the above embodiment, the reference data for searching the deviation of the orientation of the mobile antenna 1 from the difference in the reception intensity before and after the step of rotating the mobile antenna 1 by one step is stored in advance. If the mobile antenna 1 is rotated by one step to read the misalignment, then the antenna 1 can be directed to the desired azimuth by rotationally driving the misalignment, so that satellite acquisition / tracking can be performed. The time required for can be greatly reduced. Therefore, even when the vehicle equipped with the mobile antenna 1 changes its traveling direction significantly in a short time due to a sharp curve or the like, the antenna 1 can be oriented to the azimuth angle at which the reception intensity is maximum in a short time. It is possible to minimize reception defects such as interruption of broadcasting.

In the above embodiment, the case where the azimuth angle of the mobile antenna 1 is changed has been described, but when changing the elevation angle, the same reference data as above is stored in advance and rotated by one step. After the displacement of the antenna 1 is read out, the antenna 1 can be rotationally driven by a necessary angle to direct the desired elevation angle. However, since the tracking range of the elevation angle of the mobile antenna is narrow, even if the same step track system as that of the conventional example is adopted, no great trouble occurs.

Further, in the above embodiment, from the difference in the reception intensity before and after the rotation when the mobile antenna 1 is rotated by a unit angle,
Although the remaining rotation angle required for the antenna 1 is calculated, the remaining rotation angle can be calculated based on the ratio of the reception strength instead of the difference of the reception strength.

[0022]

As described above, according to the present invention in which the control data is stored in advance, the remaining amount necessary for the antenna is determined from the degree of change in the reception intensity when the mobile antenna is rotated by a unit angle. Since the rotation angle of the antenna can be determined, by rotating the moving antenna at a stretch by the rotation angle thus determined, the antenna can be rotated in the desired direction with the maximum reception intensity in a short time, and the satellite acquisition It has an excellent effect that the time required for tracking can be greatly reduced, and as a result, reception failure hardly occurs even when a vehicle equipped with a mobile antenna changes its traveling direction in a short time due to a sharp curve etc. , Can improve the practicality and reliability.

[Brief description of drawings]

FIG. 1 is a block diagram schematically showing a control relationship of a vehicle-mounted satellite tracking device according to an embodiment.

FIG. 2 is a flowchart showing a satellite acquisition / tracking operation of the same embodiment.

FIG. 3 is a block diagram schematically showing the control relationship of a conventional vehicle-mounted satellite tracking device.

FIG. 4 is a flowchart showing a satellite acquisition / tracking operation of the conventional example.

FIG. 5 is a characteristic diagram showing the relationship between the direction of a mobile antenna and the reception intensity.

[Explanation of symbols]

 1 Mobile Antenna 2 Driving Device 3 Control Device 4 Receiver (Detection Unit) 5 Computing Device 6 Level Memory (Temporary Storage Unit) 7 Memory Table (Comparison Data Storage Unit)

Claims (2)

[Claims] 1. A contrast in which the degree of change in reception intensity before and after rotation obtained when a mobile antenna is rotated by a predetermined unit angle is associated with the deviation of the orientation of the antenna with respect to the direction in which the reception intensity is maximum. If the mobile antenna is stored in advance and the degree of change in the reception intensity before and after the rotation is calculated by actually rotating the mobile antenna by a unit angle, the rotation angle of the antenna required to maximize the reception intensity is calculated as described above. A satellite tracking method for a mobile antenna, characterized in that the antenna is rotationally driven by the rotational angle determined in this way based on the reference data. 2. A mobile antenna whose azimuth can be changed, a drive unit for rotationally driving this antenna, a control unit for controlling this drive unit, and a detection unit for detecting the reception intensity of a signal received by the antenna. In a satellite tracking device having a temporary storage unit for temporarily storing the reception intensity of the antenna detected by the detection unit, a change in reception intensity before and after rotation obtained when the mobile antenna is rotated by a unit angle. And a deviation of the orientation of the antenna with respect to the direction in which the reception intensity is the maximum are stored in advance, and a comparison data storage unit is provided. The degree of change in the reception intensity of the antenna is calculated, and the deviation of the orientation of the antenna corresponding to the calculated value is read from the reference data storage unit and corresponds to the deviation of the orientation. A satellite tracking device comprising: a calculation unit that outputs a signal for giving a rotation angle to the antenna to the control unit.