JPH0626284B2 - 3-axis antenna control method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a three-axis antenna control method, and more particularly to a zenith using a directional antenna of a three-axis mount provided with three axes of an azimuth axis, an elevation axis and an orthogonal elevation axis. The present invention relates to a three-axis antenna control method for tracking a medium altitude satellite passing in the vicinity in a self tracking mode.

[Conventional technology]

Of all omnidirectional antenna support methods, a horizontal elevation axis (EL axis) is provided on an azimuth revolving base that can rotate around a vertically provided azimuth axis (AZ axis), and around this EL axis. The AZ-EL mount system in which the directional antenna is mounted so as to be rotatable from the horizontal to the zenith is structurally most advantageous and widely used. However, this method has a drawback that the rotational angular velocity around the AZ axis becomes very large when tracking a satellite passing near the zenith. On the other hand, a horizontally fixed axis (X axis)
The XY mount, which has a movable axis (Y axis) that rotates around this fixed axis and is orthogonal to this fixed axis, does not hinder tracking of satellites passing near the zenith, but tracking of satellites with a low elevation angle. In addition to the drawbacks, the support structure becomes large, which is not suitable for large antennas with a large diameter.

As one method for solving the above problem, an orthogonal elevation axis (XEL axis) orthogonal to the EL axis is provided on the AZ-EL mount, and the directional antenna can be rotated around this XEL axis only within a limited range. Japanese Unexamined Patent Publication No. 60-22803 proposes a drive control method that has a mounted triaxial mount antenna and can reduce the rotatable range around the XEL axis. With this method, when tracking a satellite that passes near the zenith, by driving the satellite in advance around the AZ axis before reaching the maximum elevation angle, half the rotation range around the XEL axis is not driven. The method can be limited to the following.

FIG. 6 shows 3 described in the above-mentioned JP-A-60-22803.
FIG. 7 is a block diagram of the control system of the axial mount antenna, and FIG. 7 is a flow chart for explaining the operation of FIG. 6th below
This control method will be described with reference to FIGS.

The three-axis antenna control system shown in FIG. 6 includes a tracking receiver 1 that detects two error signals 101 and 102 that are orthogonal to each other, and trajectory prediction calculation based on the angle display information from each axis angle detector 2, 3, and 4. Zenith tracking device 5 for performing EL axis drive system 6, A
The Z-axis drive meter 7 and the XEL-axis drive system 8 are constituted by respective axis drive systems. When the satellite position exceeds the lower limit and the initial acquisition of the satellite ends and the reception level of the tracking receiver 1 becomes self-trackable, the XEL axis is displayed as an angle as shown in step 201 of FIG. The position is fixed at 0 ° and self-tracking is performed using only the AZ axis and the EL axis as in the case of a normal AZ-EL mount. If the elevation angle exceeds a certain value during this time, an orbit prediction calculation is performed in step 202, and when it is determined that the required drive speed of the AZ axis exceeds the maximum drive speed when the satellite passes near the zenith, the mode is switched to the zenith tracking mode. As shown in step 203, the AZ axis is pre-driven at a constant speed, the error signal 102 of the tracking receiver 1 is switched from the AZ axis drive system 7 to the XEL axis drive system 8, and self-tracking by the EL axis and the XEL axis is performed. . When the satellite passes near the zenith and the elevation angle becomes less than the predetermined angle, the AZ axis constant speed drive is terminated and the AZ axis and EL axis return to the self-tracking mode again, and when the elevation angle decreases and reaches the lower limit, tracking is performed. The operation ends.

[Problems to be solved by the invention]

As shown in the above-mentioned example, in the conventional three-axis antenna control method, the error signals 101 and 102 orthogonal to each other in the tracking receiver 1 are used in most areas except the vicinity of the zenith, as in the case of the AZ-EL mount. Controls the rotations of the AZ and EL axes, and in the zenith tracking mode that tracks satellites near the zenith, EL
It is configured to perform self-tracking using the axis and the XEL axis. The connection of the error signal output of the tracking receiver 1 is changed during the self-tracking operation, and accordingly, the control sensitivity adjustment of the AZ axis is performed. Therefore, there is a problem in that it is complicated to insert or remove the cosec correction circuit.

An object of the present invention is to provide a three-axis antenna control method that can be used while the output of a tracking receiver is always connected to the EL axis and the XEL axis and does not require connection change of the tracking receiver output during operation. is there.

[Means for solving problems]

The three-axis antenna control method according to the present invention includes a vertical azimuth axis, a horizontal elevation axis that can rotate about the azimuth axis, and an orthogonal elevation axis that can rotate about the elevation axis and that is orthogonal to the elevation axis. A three-axis mount antenna equipped with a directional antenna mounted so as to be able to rotate within a limited angle range around the orthogonal elevation axis and a tracking receiver that detects a pointing direction error of the directional antenna is self-assembled. In a three-axis antenna control method for controlling in a tracking mode, the rotations of the normal elevation axis and the orthogonal elevation axis are speed-controlled so that mutually orthogonal error signal components from the tracking receiver are minimized, and the azimuth axis, The angle display of the azimuth axis and the command angle calculated by a predetermined functional relationship from the angle display of each rotation axis of the elevation axis and the orthogonal elevation axis are matched so as to be the same. Is configured to position control the rotation of the position axis.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

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

In FIG. 1, error signals 101 and 102 from a tracking receiver (not shown) that are orthogonal to each other are converted into digital signals by A / D converters 9 and 10, respectively, and then servo control circuits 11 and 12 and tracking are performed. D- via the mode switch 13
The speed control signal 10 of the EL axis and XEL axis drive system is added to the A converters 14 and 15 and converted into an analog signal.
It is sent out as 3,104.

On the other hand, the angle display signal of each axis detected by the resolver (not shown) is converted into a digital signal by the resolver converters 16, 17, and 18, and the command angle from the coordinate conversion circuit 19 or the angle command generation circuit 20 is output. Information 105, 106,
After being compared with 107, the servo control circuits 21, 22,
It is sent to the tracking mode switch 13 via 23. In the self-tracking mode in which the tracking mode switches 13 and 13a are connected to the A side (P is the program tracking mode, S is the speed control mode), the EL axis and XEL axis drive systems are always operated by the error signal from the tracking receiver. The AZ axis drive system is controlled by the command angle information from the angle command generating circuit 20, and position control is performed so that the angle display of the AZ axis matches the command angle of the angle command generating circuit 20. ing. The angle command generation circuit 20 is a circuit that performs trajectory prediction calculation based on the angle display information of each axis, and generates command angle information of the AZ axis from this prediction result.

FIG. 2 is a flow chart for explaining the operation of the embodiment of the angle command generating circuit shown in FIG. 1, showing the case of a three-axis mount antenna capable of rotating about the EL axis up to 180 degrees beyond the zenith. There is. When the satellite position exceeds the lower limit and the tracking receiver output becomes self-trackable, E
Self-tracking is performed by controlling the L-axis and XEL-axis drive systems, and as shown in step 204, the command angle Θ _AZ for the AZ-axis drive system is set so that Θ _AZ = θ _AZ −θ _XEL (1) To be done. Here, θ _AZ and θ _XEL are angle displays of the AZ axis and the XEL axis, respectively. Since the position of the AZ axis is controlled so that the angle display θ _AZ becomes equal to the command angle θ _AZ , the control is performed so that θ _XEL = 0 ° from the equation (1). Next, in step 205, EL
The axis angle display θ _EL makes a trajectory prediction between 65 ° and 70 °,
The maximum elevation angle θ _ELM is calculated. θ _EL exceeds 70 °, θ _ELM
When is larger than 83 °, the process proceeds to step 206, and the angle command generating circuit 20 outputs the command angle information such that Θ _AZ = θ _AZ −θ _XEL + (90 ° −θ _ELM ) (2). Then, the zenith tracking mode for rotating the EL axis over the 90 ° zenith is driven. At this time, since the position control is performed so that θ _AZ = θ _AZ , the angle display of the XEL axis is θ _XEL = 90 ° −θ _ELM from the equation (2).

FIG. 3 is a vector diagram for explaining the change in the angle display of each axis when the satellite with the maximum elevation angle of 85 ° is tracked by the control method of FIG. In Fig. 3, the thin solid arrow indicates A when the satellite passes from E to W in parallel with the reference line of azimuth of 0 °.
A vector indicating the angle display of the Z axis and the EL axis, and a thick solid line arrow is a vector indicating the angle display of the XEL axis. AZ so that θ _XEL = 0 ° until the satellite elevation angle reaches 70 °
Tracking is performed by the axis and EL axis, and becomes constant at θ _AZ = 0 ° and θ _XEL = 5 ° when the satellite elevation angle is from 70 ° to almost 110 °, and tracking is performed by changing only θ _EL . With this method, the command angle of the AZ axis is constant regardless of θ _EL during zenith tracking, and the information of θ _EL is used only for trajectory prediction and switching to the zenith tracking mode, and the configuration of the angle command generation circuit 20 is simple. Therefore, there is a feature that mutual control between the axes is small and stable control can be easily performed.

The flow chart shown in FIG. 2 shows a case where the command angle Θ _AZ is expressed by the equation (2) regardless of θ _EL at the time of zenith tracking in step 206, but the command angle Θ _AZ is a function of θ _EL . The angle command generation circuit may be configured so that θ _AZH = θ _AZ −θ _XEL + f (θ _EL ) (3).

For example, when θ _EL is 70 ° and 110 °, f (θ _EL ) = 0
When θ and θ _EL are 90 °, f (θ _EL ) = 90 ° −θ _ELM = 5 °, and if f (θ _EL ) is set to continuously change like a cosine function during this period, the third The angle display of each axis when tracking the same satellite as in the case of the figure shows changes as shown in FIG. 4, and there is a characteristic that θ _XEL does not change suddenly.

Although the above description has been made on the case of controlling a three-axis mount antenna rotatable from 0 ° to 180 ° around the EL axis, the present invention has a rotation range around the EL axis of 0 ° to 90 °.
It can also be applied to a 3-axis mount antenna up to °. That is, when the maximum elevation angle θ _ELM is expected to exceed a certain value by orbit prediction, the AZ-axis preceding drive similar to the method described in Japanese Patent Application Laid-Open No. 60-22803 described in the prior art is used. After reaching a certain value, the vector for the angle display of the AZ axis and the EL axis may be moved along a predetermined certain locus. FIG. 5 is a vector diagram showing changes in the angle display of each axis when the satellite passes right above the antenna in the azimuth angle direction of 0 ° to 180 °, and the angle command generation circuit 20 shown in FIG. The command angle from is up to 70 ° in Eq. (1), and above 70 ° becomes Eq. (3), f
When (θ _EL ) is set to be the length of the thick solid arrow vector, the angle display of the AZ axis and EL axis is θ _EL
It shows that it changes from = 70 ° along the broken line.

〔The invention's effect〕

As described above, according to the present invention, when the satellite passing near the zenith is tracked in the self-tracking mode by using the 3-axis mount antenna, the output of the tracking receiver is connected from the AZ axis to the XEL axis during tracking. There is an effect that it is not necessary to change and various problems associated with switching can be eliminated.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG.
FIG. 3 is a flow chart for explaining the operation of the embodiment of the angle command generating circuit shown in FIG. 3, FIGS. 3 to 5 are vector diagrams showing changes in the angle display of each axis during satellite tracking, and FIG. A block diagram of an example of the axial antenna control method, and FIG. 7 is a flow chart for explaining the operation of FIG. 1 ... Tracking receiver, 2, 3, 4 ... Angle detector, 5 ...
Zenith tracking device, 6, 7, 8 ... Drive system, 9, 10 ... A
-D converter, 11, 12, 21, 22, 23 ... Servo control circuit, 13, 13a ... Tracking mode selector, 14,
15 ... DA converter, 16, 17, 18 ... Resolver converter, 19 ... Coordinate converter, 20 ... Angle command generating circuit.

Claims (1)

[Claims] 1. An azimuth axis provided vertically, a horizontal elevation / depression axis rotatable about the azimuth axis, an orthogonal elevation / depression axis rotatable about the depression / elevation axis and orthogonal to the elevation axis, and an orthogonal elevation axis of the orthogonal elevation axis. Controlling in a self-tracking mode a three-axis mount antenna equipped with a directional antenna mounted so as to be able to rotate within a limited angular range and a tracking receiver for detecting pointing error of this directional antenna In a three-axis antenna control method, rotations of the elevation axis and the orthogonal elevation axis are always controlled so that error signal components orthogonal to each other from the tracking receiver are minimized, and the azimuth axis, elevation axis and orthogonal elevation axis are controlled. The rotation of the azimuth axis is controlled so that the command angle calculated by a predetermined functional relationship from the angle display of each rotation axis of the axis coincides with the angle display of the azimuth axis. 3-axis antenna control method characterized by.