JP3097797B2 - Mobile antenna satellite tracking method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of tracking a mobile antenna mounted on a vehicle such as an automobile and receiving a signal transmitted from a communication satellite or a broadcasting satellite, and a satellite tracking using the mobile antenna. Related to the device.

[0002]

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

As shown in FIG. 3, a conventional on-vehicle satellite tracking device includes a movable antenna 1 having a vertical axis and an azimuth that can be changed, and a driving device 2 for rotating the movable antenna 1 in a stepwise manner. A control device 3 for controlling the driving device 2; a receiver 4 to which a high-frequency signal received by the mobile antenna 1 is supplied; and a reception intensity such as a voltage proportional to the intensity of the high-frequency signal from the receiver 4. Arithmetic unit 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 strength of the high-frequency signal supplied from the mobile antenna 1, and the detection value is used to set the mobile antenna 1 to a predetermined unit angle (step angle). The data is supplied to an arithmetic unit 5 for comparing the magnitude of the reception intensity before and after the rotation when rotated, and to a level memory 6 for temporarily storing data and reading it out 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.

[0004] Next, the operation of the above-mentioned conventional vehicle-mounted satellite tracking device for directing the mobile antenna 1 to a desired azimuth at which the reception intensity becomes maximum will be described with reference to FIG.

Now, the control device 3 controls the mobile antenna 1
Assuming that the rotational drive direction is set to the clockwise direction (procedure 1), in this state, the reception intensity as an initial value is first detected (procedure 2), and the detected value is compared with the reception intensity for comparison. Lm is temporarily stored in the level memory 6 (procedure 3). Next, the mobile antenna 1 is rotated by a predetermined unit angle, that is, one step in the set rotational drive direction (step 4), and the reception intensity L after rotation is detected (step 5). The arithmetic unit 5 compares the detected value Lm read from the level memory 6 before the one-step rotation with 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 angle by rotating it, so that L is set as a new comparison reception intensity Lm without changing the rotational driving direction of the mobile antenna 1. After being temporarily stored in the memory 6 (procedure 7), the procedure returns to the above procedure 4, and the mobile antenna 1 is rotated one step in the same direction as the previous time, that is, clockwise. On the other hand, in step 6, the comparison result is L ≦ Lm
In this case, it can be determined that the mobile antenna 1 is moving away from the desired azimuth even if it is rotated.
A signal for setting the rotational drive direction of the camera to the opposite direction to the previous one is output from the arithmetic unit 5 to the control unit 3 (step 8).
Further, L is temporarily stored in the level memory 6 as a new comparison reception intensity Lm (procedure 9).
Then, the mobile antenna 1 is rotated by one step in the direction opposite to the previous time, that is, in the counterclockwise direction. Thereafter, step 4 →
When the operation of 5 → 6 → 7 → 4 or the procedure 4 → 5 → 6 → 8 → 9 → 4 is repeated several times, the mobile antenna 1 gradually turns to the desired azimuth at which the reception strength becomes maximum. Become. Then, when approaching the desired azimuth most, procedure 4 → 5 →
The operation of 6 → 8 → 9 → 4 → 5 → 6 → 7 → 4 is repeated.

[0006] When 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 operation principle is the same.

[0007]

However, the above-mentioned prior art employs a step-track method in which the rotational driving direction is determined by comparing the reception intensity before and after rotation each time the mobile antenna 1 is rotated by a unit angle. Therefore, the antenna 1 cannot be instantaneously turned to the azimuth at which the reception intensity becomes maximum.
When a vehicle equipped with a vehicle drastically changes the traveling direction in a short time due to a sharp curve or the like, there is a problem that it takes time to acquire and track a satellite, and communication and broadcasting are interrupted.

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

[0009]

SUMMARY OF THE INVENTION The first object of the present invention is to change the degree of change in reception intensity before and after rotation obtained when a mobile antenna is rotated by a unit angle, and the direction in which the reception intensity is maximized. (A)
Is stored in advance based on a characteristic curve that can be approximated by the nth power of cosA, and the mobile antenna is actually rotated by a unit angle to obtain the change in the reception intensity before and after the rotation. Once the degree has been calculated, the rotation angle of the antenna required for maximizing the reception strength is determined based on the reference data, and the antenna is rotated by the determined rotation angle.

A second object of the present invention is to provide a mobile antenna capable of changing an azimuth, a driving unit for rotating the antenna, a control unit for controlling the driving unit, and a receiving unit for controlling the driving. In a satellite tracking device having a detection unit that detects the reception intensity of the obtained signal and a temporary storage unit that temporarily stores the reception intensity of the antenna detected by the detection unit, the mobile antenna is rotated by a unit angle. The degree of change of the reception intensity before and after rotation, which is sometimes obtained, and the deviation of the direction of the antenna from the direction in which the reception intensity is maximum (A)
And a control data storage unit stored in advance in association with a characteristic curve that can be approximated by the nth power of cosA, and when the mobile antenna is rotated by a unit angle, before and after rotation of the antenna. Calculate the degree of change in reception strength,
An arithmetic unit that reads a deviation of the direction of the antenna corresponding to the calculated value from the data storage unit for comparison and outputs a signal for giving a rotation angle corresponding to the deviation of the direction to the antenna to the control unit; This is achieved by providing

[0011]

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

[0012]

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

The on-vehicle satellite tracking apparatus shown in FIG. 1 differs greatly from the prior art in that the function of the arithmetic unit 5 and the point that a memory table 7 in which comparison data is stored in advance are added. Numeral 5 calculates the difference between the reception intensities before and after rotation so that necessary information can be read from the reference data. In other words, this satellite tracking device has a movable antenna 1 having a vertical axis and an azimuth that can be changed, a driving device 2 for rotating the moving antenna 1 in a stepwise manner, and a control device for controlling the driving device 2. The control device 3, a receiver 4 to which a high-frequency signal received by the mobile antenna 1 is supplied, and an arithmetic device 5 to which reception intensity information such as a voltage proportional to the intensity of the high-frequency signal is supplied from a detection unit of the receiver 4 A level memory 6 that is connected to the arithmetic unit 5 and temporarily stores data and can be read as needed; and a memory table 7 that is connected to the arithmetic unit 5 and can read comparison data. Have. When the mobile antenna 1 is rotated by a predetermined unit angle (step angle) about the vertical axis, the arithmetic unit 5 calculates the difference between the reception intensity before and after the rotation while referring to the data in the level memory 6, and The deviation of the direction of the antenna 1 corresponding to the calculated value is read from the comparison data in the memory table 7 and a signal for giving a rotation angle corresponding to the deviation of the direction to the antenna 1 is output to the control device 3. It is supposed to.

That is, the memory table 7 stores the difference between the reception intensity before and after rotation obtained when the mobile antenna 1 is rotated by a unit angle about the vertical axis and the specific azimuth angle at which the reception intensity becomes maximum. Misalignment of the antenna 1
(A) is approximated by the nth power of cosA as shown in FIG.
Since the comparison data created in association with each other based on the characteristic curve that can be stored is stored, if the mobile antenna 1 is actually rotated by a unit angle to calculate the difference between the reception intensity before and after the rotation,
By comparing the calculated value with the reference data, the deviation of the direction of the antenna 1, that is, the necessary remaining rotation angle can be determined.

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

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

Now, the control device 3 controls the mobile antenna 1
Assuming that the rotational drive direction is set to the clockwise direction (procedure 1), in this state, the reception intensity as an initial value is first detected (procedure 2), and the detected value is compared with the reception intensity for comparison. Lm is temporarily stored in the level memory 6 (procedure 3). Next, the mobile antenna 1 is rotated by a predetermined unit angle, that is, one step in the set rotational drive direction (step 4), and the reception intensity L after rotation is detected (step 5). And the received intensity difference B (= L−Lm) between the detected value Lm read from the level memory 6 before the one-step rotation is calculated by the arithmetic unit 5 (procedure 6). Further, the arithmetic unit 5 reads the direction shift 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 this direction shift. A signal to be applied to the antenna 1 is output to the control device 3, and the mobile antenna 1 is driven to rotate by the given rotation angle (procedure 8), and turns to the desired azimuth.

Before moving from step 7 to step 8, a procedure may be added to determine the rotational drive direction according to which side the mobile antenna 1 is greatly deviated from the desired azimuth. . Also, in the above procedure 1, the mobile antenna 1
It is needless to say that the rotational drive direction may be set in the counterclockwise direction.

As described above, in the above-described embodiment, the comparison data from which the deviation of the direction of the antenna 1 can be searched from the difference between the reception intensities before and after the mobile antenna 1 is rotated by one step is stored in advance. After the mobile antenna 1 is rotated by one step to read the deviation of the direction, the antenna 1 can be rotated and driven by the rotation angle of the deviation to direct the antenna 1 to a desired azimuth angle. Can be significantly reduced. Therefore, even when the traveling direction of a vehicle equipped with the mobile antenna 1 is largely changed in a short time due to a sharp curve or the like, the antenna 1 can be directed to the azimuth with the maximum reception intensity in a short time. Poor reception such as interruption of broadcasting can be minimized.

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

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

[0022]

As described above, according to the present invention in which the reference data is stored in advance, the amount of remaining power required for the mobile antenna is determined from the degree of change in the reception intensity when the mobile antenna is rotated by a unit angle. By rotating the mobile antenna at a stroke by the rotation angle determined in this way, the antenna can be rotated in a desired direction with the maximum reception strength in a short time. It has an excellent effect that the time required for tracking can be greatly reduced, and as a result, reception failures hardly occur even when vehicles with mobile antennas change the traveling direction in a short time in a sharp curve etc. , Practicality and reliability can be improved.

[Brief description of the drawings]

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

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

FIG. 3 is a block diagram schematically showing a control relationship of a conventionally used in-vehicle satellite tracking device.

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

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

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 mobile antenna 2 driving device 3 control device 4 receiver (detection unit) 5 arithmetic unit 6 level memory (temporary storage unit) 7 memory table (reference data storage unit)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01S 3/42 H01Q 3/00-3/46 H01Q 21/00-21/30 H01Q 23/00 H01Q 25 / 00-25/04

Claims (2)

(57) [Claims] 1. A degree of change in reception intensity before and after rotation obtained when a mobile antenna is rotated by a unit angle, and a deviation of the direction of the antenna from a direction in which the reception intensity is maximum.
(A) is based on a characteristic curve that can be approximated by the nth power of cosA.
In advance, the corresponding control data is stored in advance,
If the mobile antenna is actually rotated by a unit angle and the degree of change in the reception strength before and after rotation is calculated, the rotation angle of the antenna required to maximize the reception strength is determined based on the comparison data, A satellite tracking method for a mobile antenna, wherein the antenna is driven to rotate by the rotation angle thus determined. 2. A mobile antenna capable of changing an azimuth angle, a driving unit for rotating and driving the antenna, a control unit for controlling the driving unit, and a detecting unit for detecting a 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 the deviation (A) of the direction of the antenna with respect to the direction in which the reception intensity is maximum can be approximated by the nth power of cosA.
A control data storage unit stored in advance in association with the curve is provided, and when the mobile antenna is rotated by a unit angle, the degree of change in reception intensity before and after rotation of the antenna is calculated, and the calculated value is corresponded to the calculated value. A computing unit that reads out a deviation in the direction of the antenna from the reference data storage unit and outputs a signal for giving a rotation angle corresponding to the deviation in the direction to the antenna to the control unit. Characteristic satellite tracking device.