JPH0231504A - Parabola antenna system - Google Patents

Abstract

PURPOSE:To improve the observation accuracy of various kinds of observations, such as VLBI observation, etc., by finding the moving quantity of the intersection of AZ end EL axes by detecting the moving quantity of a mirror against a moving quantity detecting means and performing modification, etc., of the received wave arriving time based on the found moving quantity of the intersection. CONSTITUTION:A moving quantity detecting means 11 which detects the moving quantity of the intersection of the AZ and EL axes 7 and 8 of a parabola antenna main body by detecting the moving quantity of a mirror 10 united with the antenna to one body is provided to a collimator 2. When the antenna is deformed and moved in the mirror axis direction by means of an external force, etc., the mirror 10 united with the antenna main body is also moved and the moving quantity of the mirror is equal to the moving quantity of the intersection of the AX and EL axes resulting from the deformation. Therefore, when the moving quantity of the mirror against the moving quantity detecting means 11 is detected, the moving quantity of the intersection of the AZ and EL axes 7 and 8 can be found and the received wave arriving time is modified based on the moving quantity. Thus the measurement accuracy of various kinds of measurements, such as VLBI measurement, etc., can be improved sharply.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a device suitable for use as a large-diameter parabolic antenna that adopts the AZ-EL mount system, and particularly relates to a device suitable for use as a large-diameter parabolic antenna that adopts the AZ-EL mount system. This invention relates to a parabolic antenna device that is capable of detecting the amount of displacement caused by an external force at the intersection with a movable horizontal axis.

[Prior art] Fig. 3 is a schematic diagram for explaining the radio wave path of a general large-diameter parabolic antenna, and Fig. 4(a) is a schematic diagram for explaining the radio wave path of a general large-diameter parabolic antenna.
FIG. 4(b) is a side view showing a detailed enlarged view of the
It is a view taken along the IVb arrow in FIG.
1 is a main reflecting mirror parabolic surface, 2 is a master collimator provided on an independent foundation that has no contact point with the main body of the parabolic antenna, 3 is the focal point of the main reflecting mirror parabolic surface 1, 4 is a sub reflecting mirror mirror surface, 5 is a focusing reflector, 6 is a focusing point, 7 is an AZ axis, 8 is an EL axis (the focusing point 6 is on this EL axis), 9
1 is the baseline reference point when performing VLBI (Very Long Range Baseline Interference) WA measurement using a parabolic antenna.
0 is a mirror for the master collimator 2 provided on the back side of the focusing reflector 5.

Next, the operation will be explained. The main reflecting mirror parabolic surface 1 is
Its mirror axis is oriented in the direction in which the radio waves arrive. The master collimator 2 is located at the intersection of the AZ axis 7 and the EL axis 8, and precisely detects the direction in which the main reflecting mirror parabolic surface 1 faces by pointing the mirror 10.

Then, the radio waves incident on the main reflecting mirror parabolic surface 1 are reflected toward the focal point 3, and the radio waves enter the main reflecting mirror parabolic surface 1 and the focal point 3.
After being reflected by the sub-reflector mirror surface 4 that shares the same, the light passes through the converging reflector 5 and reaches the converging point 6.

Using such a parabolic antenna, for example, VLB I
When performing @measurement, the time when a radio wave arriving from a distance passes the baseline reference point 9 without being reflected by the parabolic surface 1 of the main reflector is called the "received wave arrival time", It is necessary to accurately record the arrival time of received waves.

The radio waves received by the antenna arrive at the focusing point 6 with a delay corresponding to the amount reflected by the parabolic surface 1 of the main reflector, compared to radio waves that directly pass through the baseline reference point 9. This delay is
It is called antenna delay, and its approximate value can be obtained by calculating or actually measuring the radio wave path length.The arrival time of a received wave for a certain radio wave is calculated by subtracting the antenna delay time from the time when the radio wave was actually received. Obtained by subtracting.

[Problem to be solved by the invention] By the way, the parabolic antenna deforms due to external force and
When the intersection of the axis 7 and the EL axis 8 moves in the mirror axis direction of the main reflecting mirror parabolic surface 1, the antenna delay changes and an error occurs in the arrival time of the received wave.

There is a problem in that the accuracy of VLBI observation deteriorates.

This invention was made to solve the above-mentioned problems.
By making it possible to detect the amount of movement at the intersection of the axis and the EL axis,
The object of the present invention is to obtain a parabolic antenna device that improves the accuracy of various observations such as VLBIR measurement.

[Means for Solving the Problems] A parabolic antenna device according to the present invention includes a collimator that detects the amount of movement of a mirror that is integrated with the parabolic antenna, and detects the movement of the intersection of the AZ axis and the EL axis of the parabolic antenna main body. A moving amount detecting means capable of detecting the amount of movement is provided.

[Function] In the parabolic antenna device of the present invention, when the parabolic antenna is deformed by an external force or the like and moves in the direction of the mirror axis, the mirror integrated with the parabolic antenna main body also moves by the amount of movement. This amount of movement is also equal to the amount of movement of the intersection of the AZ axis and the EL axis due to the above deformation. Therefore, by detecting the amount of movement of the mirror with respect to this movement amount detection means using a movement amount detection means provided on a collimator that is independent from the parabolic antenna body, the amount of movement at the intersection of the AZ axis and the EL axis can be determined. You can ask for it.

[Embodiments of the invention] An embodiment of the present invention will be described below with reference to the drawings.

In FIGS. 1(a) and 1(b), reference numeral 2 denotes a master collimator installed on a foundation independent from the parabolic antenna main body, and is placed at the intersection of the AZ axis 7 and the EL axis 8, and the mirror 1
0, the direction in which the main reflecting mirror parabolic surface (see reference numeral 1 in FIG. 3) faces is detected. Also,
5 is a focusing reflector, 9 is a parabolic antenna for VLBI
Baseline reference point when performing WA measurement, 10 is a mirror for the master collimator 2 that is provided on the back side of the focusing reflector 5 and is integrated with the parabolic antenna body. 11 is a laser displacement meter attached to the top of the master collimator 2. (movement amount detection means), this laser displacement meter 11 is a mirror 10
A device capable of detecting the distance between the displacement meter 11 and the mirror 10 by irradiating a laser beam toward the mirror 10 and obtaining the reflection, thereby detecting the amount of movement of the mirror 1o with respect to the displacement meter 11. It is.

Next, the operation of the device of this embodiment will be explained.

In this embodiment as well, the master collimator 2
is located at the intersection of the AZ axis 7 and the EL axis 8, and the mirror 10
By pointing the main reflecting mirror parabolic surface 1, the direction in which the main reflecting mirror parabolic surface 1 faces is precisely detected.

The laser displacement meter 11 also points toward the mirror 1°, and the distance between the laser displacement meter 11 and the mirror 10 is detected based on the laser beam reflection time.

When the parabolic antenna main body receives external force and deforms so that the focusing reflector 5 moves relative to the baseline reference point 9, the mirror 10 also moves together with the focusing reflector 5, while the master collimator 2 and laser displacement meter 11 does not move because it is independent and has no contact point with the antenna.

Therefore, the distance between the mirror 10 and the laser displacement meter 11 changes, and the laser displacement meter 11 detects the mirror axis direction component of the amount of change.

Here, since the distance from the intersection of the AZ axis 7 and the EL axis 8 to the mirror 10 is sufficiently small compared to the size of the parabolic antenna body, the distance between the AZ axis 7 and the EL axis when the parabolic antenna body is deformed by external force is The amount of movement of the intersection with 8 and the amount of movement with mirror 1o are almost the same.

As described above, according to the device of this embodiment, the laser displacement meter 11 can measure the AZ axis 7 as the parabolic antenna main body deforms.
Since it is possible to detect the amount of movement in the mirror axis direction of the intersection of the EL axis 8 and the EL axis 8, by correcting the received wave arrival time based on the detected amount of movement, VLBIl! This will greatly improve the accuracy of various observations such as measurements.

In the above embodiment, a case was explained in which the laser distance meter 11 was used as the movement amount detection means, but instead of the laser distance meter 11, an x-y tracker 12 as shown in FIG. 2 was used. Good too.

In FIG. 2, 12 is an X-Y tracker (movement amount detection means) attached to the upper part of the master collimator 2;
13 is a scale plate provided on the back side of the focusing reflector 5 so as to be parallel to the AZ axis 7 and perpendicular to the EL axis 8;
is a prism provided on the back side of the focusing reflector 5. On the surface of the scale plate 13, a large number of directrix lines perpendicular to the AZ axis 7 and the EL axis 8 are drawn at equal intervals.

In the case of a device using the X-Y tracker 12 as described above, when the parabolic antenna main body is deformed by receiving an external force, the amount of movement of the mirror 10 in the mirror axis direction with respect to the baseline reference point 9 is , is detected by reading the movement of the directrix of the scale plate 13 through the prism 14 with the x-y tracker 12. Therefore, even if the XY tracker 12 is used, the same effects as in the above embodiment can be obtained.

[Effects of the Invention] As described above, according to the present invention, the movement amount of the mirror relative to the movement amount detection means can be detected by the movement amount detection means to obtain the movement amount of the intersection of the AZ axis and the EL axis. With this configuration, the accuracy of various observations such as VLBI observation can be greatly improved by correcting the arrival time of the received wave based on the detected amount of movement.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) show a parabolic antenna device according to an embodiment of the present invention, and FIG. 1(a) is a side view showing the main parts [corresponding to FIG. 4(a)]. ], FIG. 1(b) is a view in the direction of arrow Ib in FIG. 1(a), FIG. 2 is a side view showing the main parts of a parabolic antenna device according to another embodiment of the present invention, and FIG. 3 is a general view. 4(a) is a schematic diagram for explaining the radio wave path of a large-diameter parabolic antenna, and FIG.
) is a view taken along the rVb arrow in FIG. 4(a). In the figure, 1 - main reflector parabolic surface, 2 - master collimator, 5 - focusing reflector, 7 - AZ axis, 8 - EL
axis, 10-mirror, 11-.-laser type displacement meter (movement amount detection means), 12-XY tracker (movement amount detection means). In addition, in FIG. 1, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] A parabolic antenna comprising a collimator on a foundation independent of a parabolic antenna body and a mirror integrated with the parabolic antenna body, the direction of the mirror axis of the parabolic antenna being adjustable by directing the collimator toward the mirror. In the parabolic antenna, the collimator is provided with movement amount detection means capable of detecting the movement amount of the mirror and detecting the movement amount of the intersection of the AZ axis and the EL axis of the parabolic antenna main body. Device.