JPH0797725B2 - Antenna drive - Google Patents

Description

The present invention relates to a directional antenna driving device for tracking the arrival direction of radio waves transmitted from a flying target.

[Conventional technology]

As a structure for driving the antenna so as to direct it in an arbitrary direction, there are two typical systems, an AZ-El mount and an XY mount.

The configuration of the AZ-El mount system is shown in Fig. 5 (a). In the figure, 1 is a reflecting mirror forming an antenna aperture plane, 2 is a vertical axis (hereinafter referred to as AZ axis), and 3 is a horizontal axis orthogonal to the AZ axis 2 (hereinafter referred to as El axis). The antenna rotation angle around the AZ axis 2 is 0 to 360 °, and the antenna rotation angle around the El axis 3 is 0 to
If the antenna is driven so that the angle can be set to 90 °, it becomes possible to direct the antenna in any direction by combining the rotation angles of both axes.

However, as shown in FIG. 6, assuming that the angle change amount of the flight path of the target is Δe on the vertical plane including the target and Δa in the plane including the target orthogonal to the vertical plane, AZ axis 2 and El axis The antenna rotation angles of 3 are ΔAZ = Δa / cosEl (1) ΔE = Δe ((2), where AZ and El are the original angles and ΔAZ and ΔEl are the rotation angles according to the angle change amount of the target object. ) Is represented. Therefore, in order to direct the incoming radio wave direction from the target flying near the zenith, the rotation speed of the AZ axis 2 must be higher than the flight angular velocity Δa of the target.
It becomes infinite at the zenith and cannot be traced.

On the other hand, the configuration of the XY mount system is shown in FIG. In the figure, 1 is a reflecting mirror that forms an antenna aperture, and 22 and 23 are horizontal axes (referred to as X-axis and Y-axis, respectively) orthogonal to each other. 0 ° to 18 both around X axis 22 and around Y axis 23
If the antenna is driven so as to obtain a rotation angle of 0 °, it is possible to direct in any direction by combining the rotation angles of both axes.

In this case, high-speed rotation is required for the target object flying in the vicinity of the extension line of the X-axis, but the vicinity of the zenith (including the zenith) has an axis rotational speed equivalent to the flight angular velocity of the target object. If you do, you can track it.

FIG. 7 shows the structure of the antenna drive device in the AZ-El mount or the XY mount. Reference numerals 11 and 12 denote motors for driving the AZ axis or the X axis and driving the El axis or the Y axis, respectively. Reference numerals 13 and 14 denote power amplifiers for driving a required motor according to an automatic tracking error of each axis instructed from the outside.

[Problems to be solved by the invention]

As is clear from the above, in this type of antenna driving device, the XY mount system should be used when it is necessary to track a target object passing near the zenith. However, in this XY mount method, the center of gravity of the entire antenna is constant with respect to the rotation of the AZ axis and the center of gravity moves only with respect to the rotation of the El axis, unlike the AZ-El mount. The center of gravity moves with both rotations of the X axis and the Y axis.
For this reason, there are drawbacks that the structure becomes complicated and the weight becomes large in adjusting the overall balance.

The present invention has been made to eliminate the above-mentioned drawbacks, and an object of the present invention is to provide an antenna drive device based on the AZ-El mount system and capable of tracking the vicinity of the zenith.

[Means for solving problems]

The antenna drive device according to the present invention includes a first drive means for driving an antenna around a first rotation axis provided in a vertical direction, and a horizontal direction provided orthogonal to the first rotation axis. A second drive means for driving the antenna around a second rotation axis, and a third rotation axis provided orthogonal to both the first rotation axis and the second rotation axis. Third driving means for driving the antenna, a rotation speed detector for detecting a driving speed of the antenna by the first driving means, and a rotation angle of the antenna by the second and third driving means, respectively. When the rotation angle detector for detection and the rotation angles of the antenna by the second and third driving means detected by the rotation angle detector are Y and X, ΔAZ = tan ⁻¹ (tanY / ta
nX) is a tracking angle error calculator that calculates a tracking angle error ΔAZ of the antenna by the first driving means, and a driving speed of the antenna by the first driving means detected by the rotation speed detector. The first comparator for comparing with a predetermined speed, the second comparator for detecting the presence or absence of the following angle error calculated by the following angle error calculator, and the first comparator for the first comparator. When it is detected that the driving speed of the antenna by the driving means exceeds a predetermined speed, the driving by the first driving means and the second driving means to the driving by the second driving means and the third driving means When the second comparator detects that there is no tracking angle error, the drive by the second drive means and the third drive means is changed to the drive by the first drive means and the second drive means. Switch to When the target reaches the vicinity of the zenith, the range in which the AZ axis cannot follow is assisted by the rotation of the traverse axis.

As an example, in the case of an Earth-orbiting satellite with an altitude of 900 km, the rotation speed of the AZ axis is 13 ° in order to track the rotation angle of the El axis up to 88 °.
It is calculated that at least / sec is required. Therefore, the remaining El
In order to track the range of the rotation angle of the shaft from 88 ° to 90 °, the rotation speed of the AZ axis is kept as it is and the rotation angle of the traverse shaft is 88 °.
It has ~ 92 °.

[Action]

In the present invention, since the traverse axis acts only in the vicinity of the zenith due to the configuration as described above, its rotation range may be narrow (4 ° in the above example),
Within that range, the XY mount is formed together with the El axis, so that tracking near the zenith can be easily performed.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 2, 1 is a reflecting mirror that forms an antenna aperture, 2 is the AZ axis as the first rotation axis, and 3 is El as the second rotation.
An axis 34 is a traverse axis as a third axis of rotation for rotating the reflecting mirror 1 around a horizontal axis orthogonal to the El axis 3.

Further, FIG. 3 shows the axial rotation state of the antenna viewed from the zenith with respect to the target object passing near the zenith. 41 is the central position of Antea, 42 is the position of the target, and 53 is the flight path of the target.

FIG. 1 shows the configuration of a driving device for driving such anteer. In the figure, 11, 12, and 37 are AZ axes.
A motor for driving the 2, El axis 3, and the traverse axis 34. 38 is the detector for the rotational speed of AZ axis 2, 39 and 40 are each the El axis
3, rotation angle detectors of the traverse shaft 34, 13, 14, 43 are power amplifiers for driving the respective motors 11, 12, 37 in accordance with required external command angles. 44 is AZ-El AZ while driving both axes
The comparator that detects when the shaft rotation speed has reached the maximum, 45 is
A follow-up angle error calculator that calculates a follow-up angle error ΔAZ of the AZ axis 2 according to a calculation formula described later based on the rotation angles obtained from the rotation angle detectors 39 and 40 of the El axis 3 and the traverse axis 34,
46 to 48 are switchers for switching the inputs of the power amplifiers 13, 14, and 43 by AZ-El axis drive and AZ-El-traverse axis drive, and 49 is whether or not ΔAZ calculated by the error detector 45 is 0 °. It is a comparator that detects whether or not.

Here, when the AZ axis speed reaches the maximum in the comparator 44,
The switches 46 to 48 shift from the state of to the state of. After this, it is shown that the comparator 49 shifts from the state where ΔAZ = 0 °.

Next, the operation will be described.

In FIG. 3, the antenna is now automatically tracking the target so that the beam center of the antenna is directed in the direction of the radio wave coming from the target by driving both the AZ axis 2 and the El axis 3. It is assumed that the target reaches the vicinity of the zenith, the AZ axis 2 is in a region where the target cannot be tracked, and the traverse axis 34 is not driven. At this time the third
In the figure, it is shown that the AZ axis tracking angle error of ΔAZ has occurred.

Whether or not the rotation speed of the AZ axis 2 can no longer track the target is detected by the tacho generator 38 attached to the AZ axis 2, for example, and this is the maximum possible rotation speed of the AZ axis 2. It can be easily determined by comparing with the comparator 44 whether or not it has reached.

When the rotation speed of the AZ axis 2 reaches the maximum, the El axis and the traverse axis 34 are moved from the target tracking by driving both the AZ axis 2 and the El axis 3.
Switch the terminals of the switching devices 46 to 48 to the side so that tracking is performed by driving both axes. The El shaft 3 and the traverse shaft 34 form a so-called XY mount, and in the state shown in FIG.
El is the rotation angle of the El shaft 3 by the mount, and El is the rotation angle of the traverse shaft 34 by the traverse (XY) mount.
If the rotation angle of X, El axis 3 is Y It is represented by. Therefore Becomes That is, the rotation angle of the El axis 3 when originally tracked by the AZ-El mount is Δ as shown in the equation (4).
It can be seen that even if AZ occurs, the angle changes continuously, while the traverse axis changes from the original 90 ° state to the rotation angle shown in equation (3). Therefore, the non-followable state of the AZ axis 2 in FIG. 3 can be followed by driving both the El axis 3 and the traverse axis 34, and the automatic tracking of the target object can be continuously continued.

However, in order for the target object to exit the vicinity of the zenith and return to the original drive of the AZ and El axes, the AZ axis 2 should be replaced by the El axis 3 and the traverse axis.
Maximum of ΔAZ calculated by the follow-up angle error calculator 45 based on the equation (5) from both rotation angles Y and X detected from the angle detectors 39 and 40 attached to each axis of 34 so as to be 0 °. You need to drive at speed. Δ when the target leaves near the zenith
AZ gradually becomes smaller, and finally AZ axis 2 can follow. In this rotation, it is possible to follow the target object by driving with both the AZ axis 2 and the El axis 3, so ΔAZ = 0 ° is the comparator.
Detected at 49, switch the switching devices 46 to 48 to the automatic tracking side (side) by the AZ-El mount. At this time, if ΔAZ = 0 ° in the equations (3) and (4), X = 90 °, Y = El,
It can be seen that the traverse axis 34 returns to the original state and the El axis is equal to the rotation angle of the El axis in the AZ-El mount.

The flow of the above operation is summarized as shown in FIG.

When such a drive system is used, the AZ and El angles of the target, including the vicinity of the zenith, are expressed as AZ _T and El _T , respectively, and can be expressed by the following equation.

Where AZ is the rotation angle of AZ axis 2, Y is the rotation angle of El axis 3, ΔAZ
Is the following angle error of the AZ axis 2 calculated from the rotation angle of the traverse axis 34 and the El axis 3 when the AZ-El-traverse axis is driven.

By the way, as an antenna driving device made by using the same principle as that of the present invention, there is disclosed in Japanese Patent Laid-Open No. 59-194505.
There is a device described in the publication. This device is intended for the reflection type parabolic antenna, and the traverse axis that rotates the sub-reflecting mirror in the horizontal plane orthogonal to the El axis is the third axis (the rotation of the sub-reflecting mirror makes the beam direction of the main reflecting mirror equivalent. It utilizes that it can rotate in the same direction). In this case, since the sub-reflecting mirror itself is generally lighter than the main-reflecting mirror, there is an advantage that driving is easy. However,
In this conventional device, the range in which the rotation of the sub-reflecting mirror is equivalent to the rotation of the main reflecting mirror in the beam direction is about the beam width of the main reflecting mirror. Can not be removes. Therefore, in a large-diameter parabola in a higher frequency band, the tracking range near the zenith is limited, and it cannot be applied if the flight speed of the target becomes high.

On the other hand, in the apparatus of the present embodiment, the drive range of the traverse axis can be set arbitrarily, and therefore, the tracking range is not limited, and even in a high frequency band, a large diameter, or a high flight speed of the target object. It becomes possible to track.

〔The invention's effect〕

As described above, according to the present invention, the first drive means for driving the antenna around the first rotation axis provided in the vertical direction, and the horizontal drive provided orthogonal to the first rotation axis. A second drive means for driving the antenna around a second rotation axis in the direction of rotation, and a third rotation axis provided orthogonal to both the first rotation axis and the second rotation axis. Third driving means for driving the antenna around, a rotation speed detector for detecting a driving speed of the antenna by the first driving means, and a rotation angle of the antenna by the second and third driving means .DELTA.AZ = tan.sup.- ¹ (tanY / tan), where Y and X are the rotation angles of the antennas detected by the rotation angle detectors and the second and third driving means detected by the rotation angle detectors, respectively.
X), a follow-up angle error calculator for calculating the follow-up angle error ΔAZ of the antenna by the first drive means, and a drive speed of the antenna by the first drive means detected by the rotation speed detector. The first comparator for comparing with a predetermined speed, the second comparator for detecting the presence or absence of the following angle error calculated by the following angle error calculator, and the first comparator for the first comparator. When it is detected that the driving speed of the antenna by the driving means exceeds a predetermined speed, the driving by the first driving means and the second driving means to the driving by the second driving means and the third driving means When the second comparator detects that there is no tracking angle error, the drive by the second drive means and the third drive means is changed to the drive by the first drive means and the second drive means. Switch to Since it is provided with the switching means, in the antenna configuration based on the lightweight AZ-El mount, as described above, the driving range orthogonal to the AZ axis and the El axis is added with a slight traverse axis, It is possible to continuously track a target flying in all areas including the zenith, and since it has a simple traverse axis compared to the XY mount, it is possible to achieve weight reduction similar to the AZ-El mount. It has the effect of being very effective when applied to a zenith tracking antenna with severe weight restrictions.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an antenna driving device according to an embodiment of the present invention, FIG. 2 is a diagram showing a configuration of an AZ-El-traverse mount, and FIG. 3 is a view showing the vicinity of the zenith in an embodiment of the present invention. FIG. 4 is a diagram showing an axial rotation state of the antenna with respect to the target object, FIG. 4 is a diagram showing an antenna driving sequence according to an embodiment of the present invention, and FIG. 5 (a) is a diagram showing a configuration of a conventional AZ-El mount, FIG. 5 (b) is a diagram showing a configuration of a conventional XY mount, and FIG. 6 is AZ, El in FIG. 5 (a).
7 is a diagram for explaining the angle conversion of FIG. 7, and FIG. 7 is a schematic configuration diagram of a conventional antenna driving device. 2 ... 1st rotation axis (AZ axis), 3 ... 2nd rotation axis (El
Axis), 34 ... Third rotation axis (traverse axis), 38 ... Rotation speed detector, 44 ... Comparator, 39, 40 ... Rotation angle detector, 45 ... Follow-up angle error detector, 49 ...... Following angle error comparator, 46-48 …… Drive input selector for the first, second and third rotating shafts. The same reference numerals in the drawings indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A first drive means for driving an antenna around a first rotation axis provided in a vertical direction, and a second horizontal direction provided orthogonally to the first rotation axis.
Second driving means for driving the antenna around a rotation axis of the antenna, and the antenna around a third rotation axis provided orthogonal to both the first rotation axis and the second rotation axis. Driving means for driving the motor, a rotation speed detector for detecting a driving speed of the antenna by the first driving means, and a rotation angle of the antenna by the second and third driving means, respectively. When the rotation angle detector and the rotation angles of the antenna by the second and third driving means detected by the rotation angle detector are Y and X, ΔAZ = t
A follow-up angle error calculator for calculating the follow-up angle error ΔAZ of the antenna by the first drive means by an ⁻¹ (tanY / tanX), and the first drive means detected by the rotation speed detector. A first comparator that compares the driving speed of the antenna with a predetermined speed; a second comparator that detects the presence or absence of the tracking angle error calculated by the tracking angle error calculator; and the first comparator. When it is detected that the drive speed of the antenna by the first drive means exceeds a predetermined speed, the drive from the first drive means and the second drive means to the second drive means When the second comparator detects that there is no tracking angle error, the drive by the second drive means and the third drive means is changed to the drive by the first drive means. By 2 driving means Antenna driving apparatus characterized by comprising a switching means for switching the movement.