JPH06334423A - Tracking antenna system - Google Patents

Abstract

PURPOSE:To tract the azimuth angle direction with simple configuration and high accuracy. CONSTITUTION:A phase difference detection means B detects a phase difference between sub array antennas A1, A2 and then the phase of a phase shifter C is controlled and a synthesizer E executes in-phase synthesis. Moreover, a phase difference detected by the phase difference detection means B is subjected to averaging processing at an averaging means G to eliminate fast fluctuation in an elevation angle and the result is fed to a control means H. The control means H uses an elevating angle direction drive means F to control mechanically the elevating angle of the array antenna A. Satellite tracing is always attained in an excellent way by implementing electronic directivity control as a response to a high speed elevating angle fluctuation and implementing mechanical directivity control as a response to a low speed elevating angle fluctuation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tracking antenna which detects the arrival directions of radio waves from the outputs of a plurality of sub-array antennas and controls the direction of elevation of the antennas based on the detected arrival directions.

[0002]

2. Description of the Related Art In recent years, wireless communication using radio waves has been adopted in various fields with the advance of communication technology. That is, in addition to conventional TV broadcasting, radio broadcasting, and wireless communication, various mobile communication, satellite communication, and the like have become popular.

In such wireless communication, especially satellite communication, weak radio waves from the satellite must be received. Therefore, the most important thing is how to efficiently receive and effectively use radio waves. For this purpose, attempts have been made to receive more radio waves by using a plurality of antennas.

An array antenna is a typical example of such an attempt. In this array antenna, antenna elements having directivity in the same direction are arranged in a line or in a plane, and high-frequency signal outputs of a plurality of antenna elements are combined to increase the antenna gain. The gain can be improved by increasing the number of antenna elements, and this array antenna is very effective for receiving weak radio waves.

However, in the array antenna, since a plurality of antenna elements are arranged, the directivity becomes sharp. Therefore, when mounted on a moving body such as an automobile, the azimuth (azimuth) and elevation (elevation) of the directivity are controlled according to the movement of the moving body, and the directivity of the antenna is always directed toward the satellite. Tracking control is required.

As a method of changing the direction of directivity, there are an electronic method and a mechanical method. And
According to the mechanical method, the boresight (maximum gain direction) of the antenna can be always directed toward the satellite, and stable gain can be obtained regardless of the satellite direction. For this reason,
Many mechanical tracking methods are used.

In the mechanical tracking method, for example, in the elevation angle plane, the elevation angle of the array antenna is mechanically controlled based on the phase difference information from the upper and lower sub-array antennas, and the boresight of the array antenna is set in the radio wave arrival direction (satellite direction). To maintain. The outputs of the sub-arrays here are simply combined by a combiner and output. Further, similar control is performed on the azimuth plane based on the phase difference information from the left and right sub-array antennas. As a result, the directivity of the antenna can be always directed toward the satellite by following the traveling situation of the moving body.

Such a mechanical tracking antenna is disclosed in Japanese Patent Laid-Open No. 2-159802.
Further, in this device, as a drive device for the elevation angle surface, a device in which a pulley is provided on a rotation shaft in the elevation angle direction of the antenna and is driven by a motor via a belt is adopted.

[0009]

Now, let us consider changes in elevation angle and azimuth angle when the automobile is running. The change in azimuth is mainly due to the change of course due to the steering wheel operation. Therefore, the variation range is omnidirectional (360 °), but the variation speed is not so high.

On the other hand, the fluctuations in the elevation direction include (i) a large fluctuation range (about 20 °) when changing latitude and running on a slope, but a slow fluctuation speed (ii) vibration when driving on a rough road There are two types, one with a small fluctuation range but a high fluctuation speed.

Therefore, when the tracking in the elevation angle direction is performed by a mechanical method, it is highly accurate to follow the fluctuation of (ii),
A high-performance driving device is required, and there are problems that the entire device becomes complicated, large-sized, and costly. Also,
Even if a high-performance driving device is used, it is not always possible to obtain sufficient tracking reliability.

Further, an antenna for a mobile body is required to have a low posture. For this reason, in the elevation drive device using the pulley and the belt described above, the diameter of the pulley of the antenna rotation shaft cannot be increased, and as a result, the reduction ratio from the motor to the antenna rotation shaft cannot be increased.

Therefore, in order to obtain the required driving torque or holding torque, either (i) use a motor with a large torque or (ii) increase the total reduction ratio by using belts in multiple stages. become. However, even if such a method is adopted, there is a problem that the device eventually becomes large and complicated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a tracking antenna device which can perform tracking in the elevation direction with high accuracy with a relatively simple structure and can make the device in a low posture. The purpose is to provide.

[0015]

According to the present invention, as shown in FIG. 1, an array antenna A having at least two sub-array antennas (A1, A2) having the same normal direction in the elevation direction and arranged in parallel is provided. , One of the sub-array antennas
Phase difference detection means B for detecting the phase difference between the output of another sub-array antenna and the output of the reference sub-array antenna using one sub-array antenna as a reference sub-array antenna, and the phase of the output of the other sub-array antenna is changed according to the phase shift amount. And a first phase shifter C for controlling the amount of phase shift of the phase shifter based on the phase difference detected by the phase difference detecting means.
The control means D, the combiner E for combining the output of the reference sub-array antenna and the output of the phase shifter, and the attitude control of each sub-array antenna while maintaining the parallel relationship to change the normal direction of the sub-array antenna to change the elevation angle of the antenna. The elevation angle direction driving means F for changing the direction of the direction, the averaging means G for calculating the average value of the phase differences detected by the phase difference detecting means, and the elevation angle so that the calculated phase difference average value becomes zero. And a second control means H for controlling the driving of the direction drive means.

As described above, according to the present invention, the outputs of the sub-arrays arranged in the elevation direction are not simply combined, but the phase shifter C is used.
By changing the phase by means of and combining them, the direction of the directivity of the array antenna as a whole is electronically controlled. Further, it has an elevation direction drive means for mechanically changing the elevation angle of the array antenna A, and mechanically controls the directivity of the array antenna A. That is, in the present invention, control of directivity in the elevation direction is performed by a combination of electronic control and mechanical control. Further, the elevation direction drive means F has a low posture.

[0017]

Since the radio waves of the satellite method are very weak, an antenna with a very high gain is required to obtain a high quality image. Since the antenna is required to have a low posture, the array antenna A having a plurality of antenna elements a arranged in a plane is used.

An example of such an array antenna A is shown in FIG.
Shown in. The array antenna A of this example has 10
The antenna is composed of a total of 40 antenna elements a arranged in a row and in four rows at equal intervals. Then, by constructing the outputs from the 40 antenna elements a, a high gain antenna is obtained. Further, the directivity in the elevation direction of the array antenna A is relatively sharp as shown in FIG. Maximum sensitivity direction (bore sight direction)
Is in a direction perpendicular to the plane of the array antenna A.

Here, as shown in FIG. 4, the array antenna A has two sub-arrays A1 and A2 arranged in two rows in the vertical direction.
Consider the case of division into. Directivity G of each sub-array
The width of 2 is wider than that of 4 rows, and the maximum gain is half (G0 / 2) of the case of 4 rows. When these two sub-array outputs are simply combined in phase, the directivity of the entire array antenna A becomes equal to that of four columns. The outputs from the sub-arrays are combined in the combiner E.

Next, let us consider a case where one of the two sub-array outputs is changed in phase by a phase shifter C by -Δφ and then input to a combiner E for combination as shown in FIG. In this case, the directivity of the entire array antenna becomes maximum with respect to the arrival angle Δθ at which the signals before input to the combiner E have the same phase. The maximum gain is twice the gain in the direction of arrival angle Δθ of each sub-array. That is, Δφ and Δθ have a relationship of Δφ = (Lsin Δθ) / λ (L is the distance between two sub-arrays, and λ is the wavelength of the radio wave).

Therefore, the phase difference detecting means B is used to detect the phase difference Δφ between one reference sub-array output and the other sub-array output, and this phase difference Δφ is detected.
To enter. Then, the first control means D sets the phase shift amount of the phase shifter C to -Δφ. Therefore, by matching the phases of the two signals supplied to the combiner B, the directivity is directed in the direction of Δθ, that is, the direction of arrival of the radio wave. In this way, the directivity of the entire array antenna always faces the direction of arrival of radio waves, that is, the direction of the satellite, and electronic tracking of the satellite can be automatically performed. That is, since this electronic tracking system tracks the satellite by changing the beam elevation angle purely electronically, it can easily cope with high-speed elevation angle fluctuations.

By the way, in this electronic tracking, the maximum gain of the entire array antenna moves on a line (G2 × 2 in FIG. 5) that is twice the directivity of each sub-array. Therefore, as shown in FIG. 5, as the angle of arrival Δθ increases, the gain gradually decreases with respect to the gain G0 in the boresight direction. This gain reduction can be mitigated by increasing the number of divisions of the array antenna and widening the directivity width of each sub-array, but when the arrival angle Δθ increases, the projected area of the array antenna seen from the satellite decreases. Therefore, a decrease in gain cannot be avoided.

Therefore, in the present invention, the electronic tracking as described above is performed, and at the same time, the phase difference Δ is caused by the second control means H.
By controlling the elevation direction driving means F so that φ becomes 0, mechanically controlling the attitude of the entire array antenna to keep the boresight of the antenna in the satellite direction, and only performing electronic tracking, the projected area is reduced. Try to minimize the gain reduction of the antenna.

In the control of the elevation direction driving means F by the second control means H, the phase difference Δφ is not used as it is, but the averaging means G averages it.
When the averaging process is performed in this manner, a high-speed component of the elevation angle variation, that is, an elevation angle variation due to the vehicle vibration or the like accompanying traveling on a rough road is removed. Further, although the variation range is relatively large (20 °) when the latitude is changed or when traveling on a slope, the variation speed remains slow. Therefore, the elevation direction drive means F
May correspond to such a relatively slow change.

As described above, in the present invention, the change in the elevation angle direction, which requires a high-speed response, is taken care of electronically by the component. Therefore, the response speed of mechanical tracking may be slowed down. Therefore, using a small motor with less torque,
The elevation direction drive device F can have a simple structure.
This also facilitates the antenna device to have a low-profile structure.

Further, the ball screw means converts the rotational force of the motor in the elevation direction drive unit F into a linear motion once, and then converts it into a rotation motion in the elevation angle direction of the antenna again, thereby eliminating the need for a pulley and the like, so that the array The structure for rotating the antenna can be a low-profile structure.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vehicle-mounted satellite broadcast receiving antenna device according to an embodiment of the present invention will be described below with reference to the drawings.

In this antenna device, one planar array antenna is divided into four sub-arrays, and the broadcasting satellites are tracked based on a phase monopulse signal generated by distributing and synthesizing the outputs of the individual sub-arrays, and the sub-array is placed inside the vehicle. By outputting a reception signal to the installed BS tuner, it is possible to receive satellite broadcasting while moving.

<Mechanical System> The mechanical system of the present antenna device is roughly classified into a support mechanism, an azimuth angle drive mechanism, and an elevation angle drive mechanism. These configurations are shown in FIGS.

Support Mechanism As shown in FIGS. 6 to 8, the support mechanism includes a turntable 10, a base 12, and the like. Turntable 10
Is a disk-shaped table on which the array antenna 100 for satellite broadcast reception is mounted. The base 12 is a disk-shaped base that supports the entire antenna device, and is fixedly supported on the roof of a moving body such as an automobile. Further, the base 12 is provided with a cylindrical base frame 12a that projects upward around the periphery thereof, and a rib-shaped guide member 16 is provided in the upper part of the base frame 12a in the horizontal direction toward the inside. is there.

The turntable 10 has a shaft support mechanism 14 so that it can rotate in all directions (360 °) in the azimuth direction.
Is rotatably supported on the base 12. This shaft support mechanism 1
Reference numeral 4 denotes a central rotary joint 14a, a support portion 14c extending from the base 12 so as to surround the rotary joint 14a, a slip ring 14b formed on the upper surface of the support portion 14c, and an upper side of the shaft support mechanism 14, ,
It comprises a cap 14d connected to the turntable 10 and a bearing 14e provided between the inner side wall of the cap 14d and the outer periphery of the support portion 14c. With such a shaft support mechanism 14, the turntable 10 is attached to the base 12
On the other hand, the shaft can be stably supported. The rotary joint 14a is electrically connected to supply the signal on the turntable 10 received by the antenna to the BS tuner in the vehicle compartment. Also, the slip ring 14b
Plays a role of supplying power from the passenger compartment to a circuit on the turntable 10 via a slider (not shown) provided on the cap 14d.

Further, as shown in FIG. 6B, an auxiliary roller 3 for supporting the turntable 10 with respect to the base 12 is provided around the turntable 10 so that the rotation is smooth.
0 is provided. That is, this auxiliary roller 30
Comprises a driven roller 30b rotatably supported by a supporting portion 30a on the turntable, and the driven roller 30b travels on the base 12. Five auxiliary rollers 30 are provided every 60 °.

The radome 32 is fixed to the base frame 12a so as to cover the entire apparatus so that satellite broadcasting can be received even in the rain. The radome 32 is made of a non-metal material such as FRP or acrylic.

Azimuth angle drive mechanism The azimuth angle drive mechanism comprises an azimuth angle motor 18, a driving roller 20, and the like. The azimuth motor 18 is installed on the turntable 10 so that the rotation axis is horizontal. The output shaft of the azimuth motor 18 is connected to the upper drive roller 20 via the joint 24 and the bearing 26a. On the other hand, below the bearing 26a, a bearing 26b is attached via a spring (not shown). The driven roller 22 is attached to the shaft extending from the bearing 26b. The driving roller 20 and the driven roller 22 are installed on the peripheral portion of the turntable 10 and sandwich the guide member 16 of the base frame 12a from above and below. Also, the spring is the bearing 2
Since a force is applied between 6a and 26b in a direction in which they approach each other, the force of this spring presses the drive roller 20 and the driven roller 22 against the guide member 16,
Ground pressure is applied. By rotating the azimuth motor 18 in this state, the drive roller 20 rotates,
The drive roller 20 and the driven roller 22 include the guide member 16
The vehicle travels above and drives the turntable 10 to rotate in the azimuth direction.

Since the drive roller 20 is directly driven, when the azimuth motor 18 rotates in the CW direction (clockwise when viewed from the output shaft direction), the turntable 10 moves in the CCW direction (counterclockwise direction) when viewed from above. When the angular motor 18 rotates CCW, the turntable 10 rotates in the CW direction.

The drive roller 20 and the driven roller 2
On the surface of No. 2, a layer such as a rubber material, which is an elastic material having a large friction, is formed to prevent slippage.

Further, in this structure, both rollers 20, 22 are
At, there is a difference in radius of gyration between the inside and the outside. Therefore, if it is driven as it is, uneven wear occurs. Therefore, in this example, the guide member 16 is provided with a taper so as to be thin toward the outside, and both rollers 20, 22 are provided.
Corresponding to this, the taper is provided so as to increase toward the outside. As a result, the turntable 10
The rotation angle on the outer side (on the outer circumference side of the turntable) and on the inner side of the roller taper portion with respect to the rotation angle of is matched to prevent uneven wear.

As described above, according to this embodiment, (i) since no gear is used, there is no play and no hunting occurs.

(Ii) Since the drive is performed at the outer peripheral portion, the load (torque) applied to the roller is small. Therefore, a sufficient driving force can be generated even if the force sandwiched by the rollers is not so large.

(Iii) Since the load on the drive mechanism is small and the structure is simple, the operation reliability is high.

(Iv) Since the motor is horizontally arranged,
It is possible to realize a low profile suitable for vehicle mounting.

(V) Since the azimuth motor can be installed on the outer periphery of the turntable, the array antenna can be arranged near the center of the turntable. Since the array antenna is horizontally long, it can be efficiently arranged by passing through the vicinity of the center of the turntable, and the size of the device can be reduced.

(Vi) Since the reduction ratio is determined by the ratio of the diameter of the guide member and the diameter of the driving roller, the degree of freedom in setting the reduction ratio is high and the device design is easy.

Elevation Angle Drive Mechanism The elevation angle drive mechanism, as shown in FIG.
0, a rotary straight line conversion mechanism 52, a link mechanism 54, and an antenna support portion 56.

Array antenna 10 having a horizontally long rectangular planar shape
Both ends of 0 are supported by the antenna support portion 56 shown in FIG. 7B so that the elevation angle can be varied on the turntable 10. That is, the plate member 56a extending to the back surface side is fixed to the end portion of the array antenna 100, and the shaft 56b is fixed to the other end side of the plate member 56a. Further, since the shaft 56b is rotatably supported by the bearing 56c fixed to the turntable 10, the array antenna 100 is rotatable about the shaft 56b. Further, since the shaft 56b extends parallel to the longitudinal direction of the array antenna 100 and the surface of the turntable 10, the array antenna 100 is rotatable on the turntable 10 in the elevation angle direction. A protrusion 56d is provided on the shaft 56b of the antenna support mechanism 56, and a tension spring 56e having the other end fixed to the bearing 56c is attached to the protrusion 56d. Since the protrusion 56d extends to the turntable 10 side, the extension antenna 56e causes the array antenna 100 to move.
Is biased so that its surface rotates downward.

On the other hand, as shown in FIG. 7 (A), the output shaft of the elevation motor 50 is connected to a rotary straight line conversion mechanism 52 composed of a ball screw. The rotary straight line conversion mechanism 52 is provided with a male screw portion 52 that is rotated by an elevation motor.
The output shaft 52c connected to the female screw portion 52b is linearly moved by rotation of the elevation motor 50. The output shaft 52c is linearly moved by rotation of the male screw portion 52a.

A link mechanism 54 is connected to the rotary straight line converting mechanism 52. An output rod 54a is rotatably attached to the tip end side of the link mechanism 54, and the output rod 54a is fixed to the lower side of the back surface of the array antenna 100 perpendicularly to the array antenna.
Then, as described above, the array antenna 100 is rotated about the shaft 56b by the support mechanism 56. Therefore,
When the link mechanism 54 moves to the right side in the drawing, the lower side of the array antenna 100 is pushed by the output rod 54a, and the array antenna 100 moves upward (counterclockwise with respect to the paper surface of the drawing) against the biasing force of the tension spring 56e. Direction). On the other hand, when the link mechanism 54 moves to the left side in the drawing, the array antenna 100 rotates downward (clockwise with respect to the paper surface of the drawing).

In this way, when the elevation motor 50 rotates, its rotational motion is converted into linear motion by the rotary linear conversion mechanism 52, and the back surface of the array antenna 100 is pushed through the link mechanism 54 to rotate the antenna in the elevation direction. To drive.

Since the tension spring 56e constantly urges the array antenna 100 in the direction in which the elevation angle of the antenna is lowered, the link mechanism 54 is always subjected to a force in the direction of pushing the antenna. Therefore, it is possible to prevent the occurrence of backlash during elevation angle control by the link mechanism 54 (particularly when switching between pushing and pulling).

Further, a light shielding plate 58 of a predetermined size is attached to the link mechanism 54. Therefore, the link mechanism 5
With the linear movement of 4, the shielding plate 58 also moves. A pair of photosensors 60 functioning as limit switches are provided at predetermined positions before and after the movement of the shield plate 58. The photosensor 60 has a light emitting element and a light receiving element arranged opposite to each other, and detects when the shield plate 58 enters between them. Therefore, it can be detected by the photosensor 60 that the movement range of the link mechanism 54 has become equal to or larger than a predetermined range.
By limiting the moving amount of 4 based on the output of the photo sensor 60, the elevation angle of the antenna can be limited to this range.

Considering the whole of Japan as a service area,
The elevation angle of directivity required for satellite broadcasting reception is about 40.
It is considered to be in the range of ± 20 °. In the present embodiment, since the directivity control of ± 10 ° can be performed from the boresight of the antenna by the elevation angle electronic tracking function described later, the variable range of the antenna elevation angle is set to 40 ° ± 10 °.

The biasing direction may be changed by using a compression spring instead of the tension spring 56e. Further, instead of the link mechanism 54 described above, a configuration in which a push rod 62 and a roller 64 as shown in FIG. 9 are combined may be adopted. In this structure, the rotation linear conversion mechanism 52 linearly moves the push rod 62, and the push rod 62 is rotatably attached to the tip of the push rod 62 so that the roller 64 hits the back surface of the array antenna 100. Therefore, the movement of the roller 64 causes the array antenna 100 to rotate in the elevation direction. In this example, a protrusion 66 having a predetermined plane is provided on the back surface of the array antenna 100, the roller 64 is pressed against the protrusion 66, and the protrusion 68 is pulled toward the turntable 10 by a spring 68. Therefore, the array antenna 100 and the roller 64 are simply pressed against each other, and a fixing mechanism such as bolting is not required between them.

<Electrical System> FIG. 10 shows the configuration of the electrical system of the antenna device. As described above, the electric system of the present antenna device includes the array antenna unit 100, the combining / distributing unit 200, the phase comparing unit 300, the in-phase combining unit 400, the control unit 500, and the power supply unit 600. All such electric circuits are arranged on the turntable 10. Then, power is supplied from the automobile to the power supply unit 600 on the turntable 10 via the slip ring 14b. In addition, the received signal is transmitted to the BS inside the vehicle through the rotary joint 14a.
TV sent to tuner 700 and connected to it
The satellite broadcast is reproduced on the monitor 702.

Array Antenna Unit The array antenna 100 receives a radio wave of about 12 GHz from a satellite, converts it to an intermediate frequency (BS-IF) of about 1.3 GHz, and sends it to the combining / distributing unit 200, as shown in FIG. The part that supplies the four sub-arrays 100A1 and 1
00A2, 100A3, 100A4 and BS converters 102A1, 102A2, 102 for individual sub-arrays
A3, 102A4, and the primary local unit 104. The primary local unit 104 includes a local oscillator 104a.
And an amplifier 104b and an in-phase four-way divider 104c. Then, 10.7 GHz of the local oscillator 104a
z local signal output to each BS converter 102A1
Supply to 102A4. Each BS converter 102A1
102A4 mixes the received signal and the local signal from the primary local unit 104 to obtain an intermediate frequency signal. Then, from the BS converters 102A1 to 102A4, the intermediate frequency signals (B
S-IF signals) A1, A2, A3 and A4 are output.
The elevation driver 106 controls the rotation of the elevation motor 50, and the azimuth driver 108
The rotation of the azimuth motor 18 is controlled.

Array Antenna Configuration Sub-arrays 100A1, 100A2, 100A3, 10
The 0A4 has a shape in which one horizontally long rectangular array antenna 100 is divided into four vertically and horizontally. Here, for the sake of explanation, the lower left sub-array is 10
0A1, lower right is 100A2, upper left is 100A3, and upper right is 100A4.

In this example, the array antenna 100 is a receiving antenna, but since the transmitting antenna and the receiving antenna have a reciprocal relationship, the transmitting antenna will be described below.

The structure of one sub-array 100A is shown in FIG.
Shown in. The sub-array 100A is a waveguide 110 for power feeding.
And a plurality of antenna elements 1 provided on the waveguide 110.
24.

The waveguide 110 comprises two rows of rectangular waveguides 11.
The narrow surfaces 4 and 116 (hereinafter referred to as E surfaces) are joined to each other, and the joining surface 112 is cut near the center to provide a window 112a. The rectangular waveguide 1 is provided near the center of the window 112a.
BS converter 1 from the back side of the wide surface of 10 (hereinafter H surface)
02 feeding probe 120 is inserted.

A small hole for coupling the waveguides 114 and 116 and the antenna element 124 is provided on the center line of the front H surface of each of the waveguides 114 and 116.

As shown in FIG. 13, the antenna element 124 is a metal plate (patch) provided on the upper H surface of the waveguide 110 functioning as a ground plate with a dielectric layer 126 interposed therebetween.
The patch 128 includes a leg portion (coupling probe) 130 extending downward from the patch 128. The coupling probe 130 penetrates through a small hole 132 provided in the H surface of the waveguide 110 and projects into the waveguide 110, whereby it is electromagnetically coupled to the waveguide 110. Patch 128
Is formed on the dielectric layer 126 by a method such as photoetching or printing. Therefore, a plurality of patches 128 can be formed simultaneously.

The patch 128 has a circular shape as a whole,
It has a pair of notches at symmetrical positions. Then, the binding probe 1 is placed at a predetermined position (joint point) of the patch 128.
30 is joined. The line connecting the joining point and the patch center is set at 45 degrees with respect to the line connecting the notches.
Then, in this embodiment, the distance from the patch center of this junction point is set according to the installation position of the antenna element 124.

The coupling coefficient α of the power of a predetermined frequency transmitted from the waveguide 110 to the patch 128 is the ratio of the impedance of the coupling probe 130 itself inserted in the waveguide 110 from the patch 128 to the impedance of the patch 128. Depends on. Here, the impedance of the coupling probe 130 can be set to an arbitrary impedance depending on, for example, the length and thickness of the coupling probe 130. There are certain restrictions on the dimensions of the coupling probe 130 due to the shape of the entire antenna, and the impedance of the coupling probe 130 that can be actually changed is about several tens Ω to several hundreds Ω. Further, the input impedance of the patch 128 has different values depending on the relative dielectric constant and the thickness of the dielectric layer 126. Therefore, there are innumerable combinations of coupling coefficients α for exciting each antenna element 124 with equal amplitude.

Here, an example of the relationship between the position of the feeding point with respect to the patch 128 and the coupling coefficient α is shown in FIG. By changing the position of the feeding point in this way, the coupling coefficient α can be set to a desired value. FIG. 14 shows the coupling coefficient α when the impedance of the coupling probe 130 is ⅓ of the input impedance at the outer peripheral portion (edge) of the patch 128.

As described above, when the impedance of the coupling probe 130 and the impedance of the patch 128 are equal to each other, the degree of coupling between the two becomes maximum, and in other cases, the degree of coupling becomes smaller. Therefore, in the present embodiment, by changing the position of the junction point, the coupling degree in each antenna element 124 is adjusted while keeping the length and thickness of the coupling probe 130 in the antenna element 124 the same.

Then, as shown in FIG. 15, by setting the degree of coupling in each antenna element 124 according to the distance from the feeding probe 120, the antenna element 124 caused by the difference in the installation position with respect to the feeding probe 120.
It is possible to correct the difference in the power supplied to the antennas and to excite all the antenna elements 124 with the same amplitude.

Furthermore, the phase of the current in each antenna element differs depending on the distance from the feeding probe 120.
In this example, the phase is adjusted by changing the orientation of the antenna element 124 (arranged by rotating mechanically), and the phase of each antenna element 124 at the time of power combination is matched. That is, the direction of the line connecting the notches in the patch 128 of each antenna element 124 is changed according to the distance from the power feeding probe 120 to adjust the phase.

BS converters 102A1 to 102a4
Is connected to each of the four sub-arrays 100A1 to 100A4 via the power supply probe 120, and converts the received signal into a BS-IF signal of about 1.3 GHz. Further, in the present antenna device, tracking is performed between 100A1 between the outputs of each sub-array.
.. to 100A4 based on the phase difference, the outputs of the converters 102A1 to 102a4 are output to the sub-array 100A.
It is necessary to maintain the phase relationship of the outputs of 1 to 100 A4. Therefore, as described above, each local signal outputs the output of one local oscillator 104a to the in-phase quad divider 104c.
We use what we distributed.

Structure of Combined Distributor In the combined distributor 200, as shown in FIG. 16, four sub-arrays 100A1 to 100A of the array antenna 100 are provided.
4 output signals A1 to A4 are distributed and combined to obtain two combined signals for obtaining an azimuth monopulse signal (left side (A1 + A3), right side (A2 + A4)) and two combined signals for obtaining an elevation monopulse signal. (Lower side (A1
+ A2) and the upper side (A3 + A4)) are generated and supplied to the phase comparison unit 300.

That is, the signals A1 to A4 are input to the two-way dividers 202, 204, 206, and 208, respectively, and two signals are output respectively. Then, the combiner 212 combines the outputs of the two dividers 202 and 206 to obtain A1 + A3, the combiner 214 combines the outputs of the two dividers 202 and 204 to obtain A1 + A2, and the combiner 216 divides into two. The outputs of the devices 204 and 208 are combined to obtain A2 + A4, and the combiner 218 combines the outputs of the two-dividers 206 and 208 to obtain A3 + A4. Therefore, from the outputs from the combiners 212 to 218, four signals for obtaining the elevation angle and azimuth angle monopulse signals supplied to the phase comparison section 300 can be obtained. In addition, the synthesizer 214,
Since the outputs of 218 are output via the two-way dividers 220 and 222, respectively, two signals of A1 + A2 and A3 + A4 are obtained, and one of them is supplied to the in-phase combiner 400.

With this configuration, since both the azimuth and elevation monopulse signals are generated from the received power of the entire array antenna, the S / N ratio of both monopulse signals is high and highly accurate satellite tracking is possible. Become.

Furthermore, the synthesizers 212, 214, 216,
By configuring 218 with a phase difference synthesizer, it is possible to generate a highly accurate monopulse signal and received signal. Here, the phase difference synthesizer, as shown in FIG.
One of the two inputs is phase-shifted by the phase shifter PS and then synthesized by the synthesizer SS.

When the direction of the array antenna 100 is deviated from the incident direction of the radio wave, the signal is output from the sub-array 4
The two signals A1, A2, A3 and A4 have a phase difference with each other. Therefore, the phase difference synthesizer shifts one of the signals on the basis of these phase differences to perform in-phase synthesis.

The synthesizer 212 synthesizes the upper and lower sub-array output signals (hereinafter referred to as the upper and lower signals. The same applies to other signals) A1 and A3.
The phase difference θ between the upper and lower signals is detected. Therefore, the phase difference θ between the signals from the upper and lower sub-arrays is set to the internal phase shifter PS.
By eliminating the above, in-phase combining of two signals with maximum efficiency can be performed. Further, in the combiner 214, the signals A1 and A
2 is a phase difference between the signals, that is, a left / right phase difference φ, a combiner 216 is a vertical phase difference θ for combining the signals A2 and A4, and a combiner 218 is a left / right phase difference for combining the signals A3 and A4. In-phase synthesis can be achieved by setting the amount of phase shift of each internal phase shifter PS based on φ.

The upper and lower phase difference θ obtained by the control unit 500 is a signal (A1 + A2) and (A3 + A4) obtained by shifting one signal by the left and right phase difference φ, and the left and right phase difference φ is similarly one signal. Are phase-shifted by the upper and lower phase difference θ and then combined signals (A1 + A3) and (A2 + A
The phase difference obtained from 4) is that the phase of each signal changes by the same value due to the influence of the phase shift, but the phase difference does not change, so the value of the phase difference is only more accurate. There is no.

According to such a configuration, even when the boresight direction of the antenna is deviated in the elevation direction, an azimuth monopulse signal having a good S / N ratio can be obtained, and similarly, the boresight direction is in the azimuth direction. An elevation monopulse signal with a good S / N ratio can be obtained even when the signals are deviated in the angular direction. Therefore, highly accurate tracking can be achieved for both the elevation angle and the azimuth angle.

Further, all the synthesizers 212, 214, 2
Instead of using the phase difference combiners 16 and 218, only some of the combiners may be phase difference combiners. For example, if only the combiners 214 and 218 are phase difference combiners, as described above, The S / N ratio of the elevation angle monopulse signal when the azimuth direction is deviated is improved, and the in-phase synthesis unit 400 is provided.
The signal supplied to is compensated for the phase difference in the azimuth direction. Therefore, by in-phase combining (A1 + A2) and (A3 + A4) in the in-phase combiner 400, electronic tracking is achieved not only in the elevation direction but also in the azimuth direction.

As shown in FIG. 18, the phase difference synthesizer includes a local oscillator LO, a phase shifter PS, and two mixers M.
It is also possible to use IX1 and MIX2 and a synthesizer SS to perform frequency conversion and in-phase synthesis at the same time. In this configuration, the phase shifter PS shifts one of the phases of the local signal from the local oscillator LO based on the phase shifter control signal, and outputs it. The mixer MIX1 mixes the phase-shifted local signal to the input 1, and the mixer MIX2 directly mixes the phase-shifted local signal from the local oscillator LO to the input 2. Therefore, the output signal of the mixer MIX1 is obtained by shifting the input 1 by the phase shift amount of the phase shifter PS. Therefore, each synthesizer 212, 214, 216, 21
By setting the phase shift amounts of the eight phase shifters PS in the same manner as in the above case, in-phase synthesis can be performed in each synthesizer.
In this configuration, the local signal, not the received signal, is phase-shifted by the phase shifter PS, so that a narrow band phase shifter can be used as the phase shifter PS.

Configuration of Phase Comparing Section As shown in FIG. 19, the phase comparing section 300 has four composite signals A1 + A3, A2 + A4 from the composite distributing section 200.
From A1 + A2 and A3 + A4, an azimuth monopulse signal and an elevation monopulse signal necessary for satellite tracking are generated.

First, the four combined signals of about 1.3 GHz input from the combining / distributing unit 200 are mixed by the mixers 302, 30.
4, 306 and 308. This mixer 302-
Secondary local signals from the secondary local oscillator 310 are supplied to the respective 308 via the in-phase quad divider 312. As described above, the reason why the output of one oscillator is divided into four in-phase in the secondary local is used in order to maintain the phase relationship of each signal as in the primary local. Then, in the mixers 302 to 308, the secondary local signals are converted into about 100 MHz (second IF signal). This second IF signal is a low-pass filter 322-328 and a band-pass filter 332-3.
By extracting the signal of about 100MHz by 38,
A signal component of a specific one channel (tracking channel) is extracted from a plurality of satellite broadcast channels. Further, switching of the tracking channel is performed by changing the frequency of the secondary local signal, and the bandpass filters 332 to 3 are used.
The second IF signal extracted at 38 is always the same frequency signal.

Left side signal A1 + converted to the second IF signal
A3 is input to the 90-degree hybrid 342 and in-phase (0
°) component and orthogonal (90 °) component. The right-side signal A2 + A4 is split into two in-phase (0 °) components by the in-phase two-way divider 344. Then, the quadrature component of the left-side signal from the 90-degree hybrid 342 and the in-phase component of the right-side signal from the in-phase two-way divider 344 are the phase comparator 346.
The left in-phase component from the 90-degree hybrid 342 and the right in-phase component from the in-phase two-way divider 344 are input to the phase comparator 348, and the respective phases are compared. Thereby, the phase comparators 346 and 348 obtain the azimuth angle monopulse signals (A sin φ, A cos φ) which are the DC components of the phase difference between the left and right signals A1 + A3 and A2 + A4. Here, A is proportional to the amplitude of the received signal, and φ is proportional to the deviation angle between the satellite direction in the azimuth plane and the boresight direction of the array antenna.

The lower signal A1 + A2 converted into the second IF signal is input to the 90-degree hybrid 352 and divided into an in-phase (0 °) component and a quadrature (90 °) component. Further, the upper signal is divided into two in-phase (0 °) components by the in-phase two-way divider 354. Then, the quadrature component of the lower signal (A1 + A2) from the 90-degree hybrid 352 and the in-phase component of the upper signal A3 + A4 from the in-phase two-way divider 354 are input to the phase comparator 356, and the lower in-phase signal from the 90-degree hybrid 352 is input. The component and the upper in-phase component from the in-phase two-way divider 354 are input to the phase comparator 358, and the respective phases are compared. This allows the phase comparator 356,
At 358, the up and down signals A1 + A2 and A3 + A4
Elevation monopulse signal (Esin which is the DC component of the phase difference of
θ, Ecos θ) is obtained. Where E is the amplitude of the received signal,
θ is proportional to the deviation angle between the satellite direction and the boresight direction in the elevation plane.

Configuration of In- Phase Synthesizing Section The in-phase synthesizing section 400, as shown in FIG.
2, a combiner 404, a phase shifter driver 406, and a bandpass filter 408. And
The lower signal (A1 + A2) output from the combining / distributing unit 200 is directly input to the combiner 404, and the upper signal (A3 + A4) output is input to the combiner 404 via the phase shifter 402. The amount of phase shift in the phase shifter 402 is controlled by the signal from the phase shifter driver 406. Control of the amount of phase shift of the phase shifter 402 by the phase shifter driver 406 is performed by the control unit 500 with the elevation angle monopulse signal (Esin θ, Eco).
After calculating the phase difference θ of the upper signal with respect to the lower signal by calculating the arc tangent (tan ⁻¹ ) from sθ), operate the 4-bit phase shifter control signal so that the phase shifter has a phase amount of −θ. Then run. Therefore, the phase of the upper signal output from the phase shifter 402 becomes the same as the phase of the lower signal directly input to the combiner 404. Therefore, the combiner 404 performs in-phase combining. The bandpass filter 408 is for removing noise.

In this way, by combining the upper and lower sub-array outputs so that they have the same phase,
The directivity in the elevation plane of the combined array antenna 100 always faces the satellite direction, and elevation electron tracking is realized. The electronic trackable range of this device is approximately ± 10 ° in the boresight direction.

In the above example, the in-phase combining section 40 is used.
The input to 0 is the signals A1 + A2 and A3 + A4 from the upper and lower sub-arrays, and the phase shifter 402 calculates the elevation phase difference θ.
Although the phase shift amount is set on the basis of the signals A1 + A3 and A2 + A4 from the left and right sub-arrays, the phase shift amount may be set on the phase shifter 402 based on the azimuth angle phase difference φ. In this case, the electronic tracking is performed for the azimuth angle instead of the elevation angle.

In this apparatus, a step variable type phase shifter is used as the phase shifter 402. An example of this configuration is shown in FIG.
Microstrip lines that transmit signals include four microstrip line pairs T1L / T1S, T having different lengths.
2L / T2S, T3L / T3S, T4L / T4S are connected via PIN diode switches SW1 to SW8. Here, the subscript L means long, S means short,
A signal is transmitted through one of the four pairs by switching the switches SW1 to SW8. And each pair T1L / T1S, T2L / T2S, T3L / T3S, T4L / T4S is 180 for BS-IF signal of about 1.3 GHz.
Since it has a phase difference of °, 90 °, 45 °, 22.5 °,
4-bit signal (SW1, SW2), (SW3, S
By controlling the switching of W4), (SW5, SW6), and (SW7, SW8), these are combined to 0.
The amount of phase shift can be controlled in 22.5 ° steps in the range of ° to 360 °.

As described above, the phase shift amount of the phase shifter 402 is 2
Because of the 2.5 ° step, the two signals may not be exactly in phase at the time of synthesis and may have a phase error of 11.25 ° at maximum. However, since the loss at the time of synthesis due to this error is extremely small, it is practically acceptable.

The received signal synthesized and produced by the in-phase synthesizer 400 passes through the rotary joint 14a,
It is sent to the BS tuner 700 installed in the vehicle compartment.

Configuration of Control Unit The control unit 500 inputs both the azimuth / elevation monopulse signals from the phase comparison unit 300, and drives the above-mentioned phase shifter for elevation electronic tracking and azimuth drive for mechanical tracking. mechanism,
Satellite tracking is performed by controlling the elevation drive mechanism.

As shown in FIG. 22, the control section 500 has four A / D converters 502 and 50 for converting an analog azimuth / elevation angle monopulse signal into a digital signal.
4, 506, 508, a CPU 512 for performing signal processing for satellite tracking and state control of the present antenna device, and a phase shifter control signal generator 514 for generating a phase shifter control signal to be supplied to a phase shifter driver 406. And an azimuth control signal generator 518 that generates an azimuth control signal to be supplied to the azimuth motor driver 108, and an elevation angle control signal generator 5 that supplies an elevation angle control signal to the elevation motor driver 106.
16 and 16.

FIG. 23 shows a control flow of the entire antenna device by the CPU 512. This antenna device is roughly divided into two operation modes, a search mode and a tracking mode.

After the device initialization (S0), the CPU 512
First, the search mode is entered. In the search mode, the reception level A (= √ {(Acos θ) ²
+ (Asin θ) ² } is checked, and it is determined whether the reception state is the reception state depending on whether the reception level A is equal to or higher than a certain threshold level (S11). If the reception level is equal to or higher than the threshold, the reception state is determined and tracking is performed. Switch to mode.
On the other hand, if the reception level A is less than or equal to the threshold level in S11, the azimuth motor driver 108
The azimuth angle motor 18 is controlled via the to set the rotation speed of the turntable 10 to [high speed]. Then, in this state, the search turn (high-speed search) is started (S12).
The rotation speed at this time is about 180 ° / second, and one rotation is performed in about 2 seconds. During the search, the reception level A is constantly monitored and it is checked whether or not the reception state has been reached (S13). The search turn is stopped at the time of reception during the search, but the speed change of the azimuth motor 18 is limited and sudden stop cannot be performed, so the speed is gradually decelerated and stopped. Therefore, normally, at this point, it has passed the receivable position,
After reversing the rotation direction (S14), the rotation speed is changed to [low speed].
The search turn (low speed search) is performed again as (the limit speed at which the vehicle can suddenly stop) (S15). Then, the reception level A is monitored and it is determined whether or not the reception state is reached (S16). Normally, the reception state is immediately after starting the low-speed search, but if the vehicle is turning or there is a shield such as a building, it becomes difficult to reacquire. Therefore, if the reception state is not reached, it is determined whether a fixed time has elapsed (timed out) (S17). If it cannot be reacquired within a fixed time, the process returns to S11 to restart the search. On the other hand, if the reception state is reached within a certain period of time, the tracking mode is entered.

In the tracking mode, the CPU 512 first obtains the reception level A from the azimuth angle monopulse signal as in the search mode, and determines whether it is in the reception state (S21).
Then, when it is confirmed that the reception state is obtained, azimuth / elevation tracking control is performed (S22).

In the case where the reception level A is lowered and the reception becomes impossible due to the blocking caused by the building or the tree during the tracking,
In S21, it is determined that the reception state is not set. In this case, the tracking operation is temporarily stopped and the process waits for several seconds.
That is, it is determined whether or not it is in the reception state (S23), and if it is not in the reception state, it is determined whether or not a fixed time has elapsed (whether or not it has timed out) (S24), and this is repeated until the time-out. Then, during the standby process, in S23, if the reception state is again obtained, the process returns to S22 to restart the tracking control. When the time-out occurs in S24 (when the reception state is not reached even after waiting for a few seconds), it is determined that the satellite has been lost, and the mode shifts to the search mode (S11) again.

Next, regarding the tracking control operation (S22),
The azimuth control and the elevation control will be separately described in detail.

Configuration of Azimuth Angle Control Azimuth angle tracking control is performed by a closed loop operation by digital signal processing. FIG. 24 is a functional block diagram of the azimuth tracking control system.
Shown in. First, the azimuth angle monopulse signals Acosφ and Asinφ from the phase comparison unit 300 are tan ⁻¹ calculator 52.
The phase difference φ is obtained by inputting 2 to the tan ⁻¹ calculation. For this φ, the loop filter processing unit 530 also uses the perfect integral loop filter to obtain the filter output φ ′. That is, the phase difference φ is input to the amplifier 532 of the gain AG1 and the amplifier 534 of the gain AG2, and the output of the amplifier 532 is input to the adder 536 as it is, but the output of the amplifier 534 is the output of the adder 538 and the adder 538. Delay unit 540 for delaying the output of 538 by one unit time
After being integrated by and input to the adder 536. Then, the loop filter output φ ′ with respect to the phase difference φ is obtained.

Then, this filter output φ'is supplied to the azimuth angle motor driver 108 as an azimuth angle control signal via the rotation direction / speed control section 550. Therefore, the azimuth motor driver 108 controls the rotation of the turntable 10 by the azimuth motor 18. As a result, the azimuth motor 18 is rotated at a speed proportional to | φ ′ | in the direction in which φ ′ becomes 0, and azimuth tracking is executed.

The response characteristic of the system is determined by the proportional gain AG1 and the integral gain AG2 of the loop filter. Actually, the proportional gain and the integral gain are determined within a range that can be sufficiently tracked to the turning motion of the automobile and the vibration due to the influence of noise and the like is reduced. Here, when the phase difference combiner shown in FIG. 21 is used as the combiners 214 and 218 shown in FIG. 20, an electronic tracking operation in the azimuth direction is performed there. Therefore, it is preferable to increase the integral gain of the loop filter 530 to relatively slow the response of mechanical tracking.

In this example, the loop filter 530
The rotation direction / speed control unit 550 is realized by software of the CPU 512.

FIG. 25 shows the relationship between the azimuth angle monopulse signal with respect to the azimuth angle of the boresight of the array antenna with respect to the satellite, and the amplitude and phase obtained from the azimuth angle monopulse signal. As can be seen from the figure, there are multiple points where the phase φ becomes 0, in addition to the point where the azimuth angle is 0. Therefore, if the closed loop operation is performed so that the phase φ becomes 0, the boresight of the array antenna will be correct. There are cases in which the direction is lost. In the present antenna device, by properly selecting the reception threshold level, the range in which the closed loop operation is performed is limited to the range where the phase | φ | <180 °, and the antenna is always controlled to be correctly oriented in the satellite direction.

Configuration of Elevation Angle Control The elevation angle tracking control uses a hybrid tracking method in which a closed loop operation by mechanical tracking and an open loop operation by electronic tracking are combined. Figure 2 shows a block diagram of the elevation tracking control system.
6 shows. First, the elevation angle monopulse signals Ecos θ and E sin θ from the phase comparison unit 300 are tan ⁻¹ calculation unit 562.
Is input to the input terminal, and the tan ⁻¹ calculation is performed here to obtain the phase difference θ. This phase difference θ depends on the signal A3 + A4 from the upper sub-array and the signal A1 + A2 from the lower sub-array.
It is obtained by the phase comparison of. Then, the phase shift amount of the upper side signal A3 + A4 of the phase shifter 402 is set to −θ, in-phase synthesis is performed, and elevation angle electronic tracking is performed.

Here, when the space between the upper and lower sub-arrays is L, and the direction of the satellite (direction of arrival of radio waves) is deviated by α with respect to the boresight direction (direction in which maximum gain is obtained = direction perpendicular to antenna). Is the phase shift θ of the radio waves received by the upper and lower sub-arrays, θ = (Lsin α) / λ 2. Therefore, the radio wave received by the upper sub-array is θ compared to the radio wave received by the lower sub-array.
Only out of phase.

Therefore, the phase shift amount in the phase shifter 402 is set to −
By setting to θ, the signals input to the combiner 404 have the same phase. Therefore, the output of the combiner 404 is such that the directivity of the antenna is directed toward the satellite. By constantly detecting the phase difference by the phase comparison unit 300 and controlling the phase shift amount of the phase shifter 402, the directivity of the antenna can be always directed in the satellite direction (radio wave arrival direction).

All the control of the directivity is performed electrically. Therefore, it becomes possible to easily follow a very high-speed change in elevation angle such as a vibration when a vehicle is running and to track the satellite.

Further, the phase difference θ which is the output of the tan ⁻¹ calculation unit 562 is input to the averaging processing unit 570. The averaging processing unit 570 includes N−1 delay circuits 572 (1) to 572 (N−1), respective outputs of the delay circuits 572 (1) to 572 (N−1), and an input phase difference θ. And are input, and an adder 574 that takes the sum of these
And a 1 / N multiplier 576 for 1 / N the output of this adder
It consists of Therefore, the average value of the phase difference θ for a predetermined time (N times the delay time of one delay circuit) is calculated, and as a result, the average phase difference θ ′ is obtained. This average phase difference θ ′ is one in which the instantaneous fluctuation of θ due to vibration or the like is removed.

Then, the sign / absolute value judgment unit 580 judges the sign and the absolute value of the average phase difference θ ′ which is the averaging result, and when | θ ′ | becomes large to some extent, θ ′.
The elevation motor 50 is rotationally controlled in the direction in which is zero to perform elevation mechanical tracking. This control is the elevation motor driver 1
Via 06. In this example, tan ⁻¹ operation 56
2. The averaging process 570 and the sign / absolute value judgment 580 are realized by the software of the CPU 512.

As described above, the mechanical tracking by the elevation angle motor 50 eliminates the high-speed fluctuation component due to vibration or the like. Therefore, it is possible to perform control to track the boresight of the antenna in the satellite direction by following changes in latitude, changes in attitude due to slopes, and the like. As a result, since a high-speed variation component in the elevation direction due to vibration or the like is dealt with by electronic tracking, good tracking characteristics can be obtained even if the response speed of mechanical tracking is slow. Further, since the response speed of the mechanical tracking in the elevation direction may be slow in this way, there is no problem even if a small one having a relatively small torque is used as the elevation motor 50, which can contribute to downsizing of the device. .

[0107] The flow chart for executing the azimuth and elevation tracking control described azimuth and elevation tracking control flow than shown in Figure 27. During the tracking operation, the processing of FIG. 27 is repeatedly executed about every 5 ms.

First, in order to control the azimuth angle, the tan ^-1 calculator 522 calculates φ = tan ^-1 (Asinφ / Acosφ) to calculate the left and right phase difference φ (S31). This phase difference φ is input to the loop filter processing unit 530, the filter output φ ′ is calculated (S32), and it is determined whether φ ′> 0 (S33). Then, the rotation direction / speed control unit 550 rotates the azimuth motor 18 forward when φ ′> 0 (S34), and when φ ′ ≦ 0,
The azimuth motor 18 is rotated in the reverse direction (S35), the speed of the azimuth motor 18 is set to a value proportional to | φ '| (S36), and the azimuth motor 18 is driven.

Next, for elevation angle control, the tan ^-1 operation unit 5
At 62, θ = tan ⁻¹ (Esin θ / Ecos θ) is calculated to calculate the upper and lower phase difference θ (S37). Then, based on this phase difference θ, the phase shift amount in the phase shifter 402 is set to −θ (S38). Further, the averaging processing unit 570 calculates the average phase difference θ ′ (S39), and determines whether the absolute value | θ ′ | of θ ′ is equal to or greater than a predetermined value (the phase difference at which the elevation angle control by the elevation angle motor 50 should be started). It is determined (S40). Then, when θ ′ is less than or equal to the predetermined value, the drive of the elevation angle motor 50 is stopped (S41). On the other hand, if | θ '| is greater than or equal to the predetermined value, it is determined whether θ'> 0 (S42). And θ '
If> 0, the elevation motor 50 is rotated forward and the pointing direction of the antenna is increased (S43). If θ '<0, the elevation motor 50 is reversed and the pointing direction of the antenna is lowered (S44). .

As described above, the azimuth angle direction can be controlled by driving the azimuth angle motor 18 based on the phase difference of the radio waves received in the left and right sub-arrays, and the elevation angle direction can be controlled by high-speed changes due to vibration or the like. The phase shifter 40
It responds at high speed by electronic control by phase shift amount control in 2, and responds to low speed changes such as latitude changes by control of the elevation angle motor 50 based on the average phase difference. As a result, the satellite can be mounted on a moving body such as an automobile to achieve good satellite tracking.

[0111]

As described above, according to the tracking antenna device of the present invention, a high-speed elevation angle fluctuation component is handled by electronic tracking, and a relatively low speed fluctuation component is handled by mechanical tracking. The system does not need to operate at high speed, the elevation drive can be simplified, and the reliability of tracking can be improved, and the cost can be reduced. Also, due to mechanical tracking, the array antenna boresight direction (maximum gain direction)
Since it can be directed toward the satellite, a high gain can be maintained regardless of the direction of the satellite as compared with the case of only electronic tracking. For this reason, it is possible to receive signals over a wide area or on a slope with a small antenna area, and it is possible to realize miniaturization suitable for vehicle mounting.

Further, since the rotational movement of the motor is once converted into the linear movement by the ball screw means, the reduction gear ratio can be increased and the driving torque of the motor can be reduced while keeping the whole device in a low posture. Further, since the ball screw itself has a position holding function, it is not necessary to increase the holding torque of the motor, and the energy efficiency of the motor can be increased. Further, the ball screw means has an elongated shape and the angle is adjusted from the back surface of the antenna element, so that the degree of freedom of arrangement and shape of the antenna element can be increased. In addition, since the driving mechanism is simple, it is easy to attach and detach the array antenna.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a tracking antenna according to the present invention.

FIG. 2 is an explanatory diagram showing an appearance of an array antenna.

FIG. 3 is an explanatory diagram showing the directivity of an array antenna.

FIG. 4 is an explanatory diagram showing the directivity of an array antenna of two sub-arrays.

FIG. 5 is an explanatory diagram showing a configuration for electronic tracking.

FIG. 6 is a front cross-sectional view showing a configuration of a main part of a mechanical system of the antenna device.

FIG. 7 is a front view showing the configuration of an elevation angle moving mechanism.

FIG. 8 is a plan view showing the main configuration of a mechanical system of the antenna device.

FIG. 9 is a front view showing another configuration example of the elevation angle moving mechanism.

FIG. 10 is a block diagram showing an overall configuration of an electric system of the antenna device.

FIG. 11 is a block diagram showing a configuration of an array antenna unit.

FIG. 12 is a schematic perspective view showing a main configuration of an array antenna.

FIG. 13 is an explanatory diagram showing a configuration of an antenna element.

FIG. 14 is a characteristic diagram showing a relationship between a feeding point position and a coupling coefficient.

FIG. 15 is an explanatory diagram showing a power feeding state for an antenna element.

FIG. 16 is a block diagram showing a configuration of a combining / distributing unit.

FIG. 17 is a block diagram showing a configuration of a phase difference synthesizer.

FIG. 18 is a block diagram showing another configuration example of the phase difference synthesizer.

FIG. 19 is a block diagram showing a configuration of a phase comparison unit.

FIG. 20 is a block diagram showing a configuration of an in-phase combining unit.

FIG. 21 is a diagram showing a configuration of a phase shifter.

FIG. 22 is a block diagram showing a configuration of a control unit.

FIG. 23 is a flowchart illustrating a tracking operation.

FIG. 24 is a block diagram showing a configuration for directional azimuth control.

FIG. 25 is a diagram showing a waveform of a signal for azimuth angle control.

FIG. 26 is a block diagram showing a configuration for directivity elevation angle control.

FIG. 27 is a flowchart showing an operation of azimuth angle and elevation angle control.

[Explanation of symbols]

 A array antenna B phase difference detection means C phase shifter D first control means E combiner F driving means G averaging means H second control means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiaki Watanabe, Nagakute-cho, Aichi-gun, Aichi Prefecture 1-41 Yokoshiro, Yokosuka Central Research Institute Co., Ltd. (72) Satoru Matsushima, Aichi-gun, Nagakute-cho, Nagachi 1 at 41 Yokochi Central Research Institute, Ltd. (72) Inventor Kazuhisa Higashi, Nagakute-cho, Aichi-gun, Aichi Prefecture

Claims (2)

[Claims] 1. An array antenna comprising at least two sub-array antennas having the same normal direction in the elevation angle direction and arranged in parallel, and one sub-array antenna among the sub-array antennas is used as a reference sub-array antenna, and other sub-array antennas. Phase difference detecting means for detecting the phase difference between the output and the output of the reference sub-array antenna, a phase shifter for changing the phase of the output of the other sub-array antenna according to the amount of phase shift, and detection by this phase difference detecting means The first control means for controlling the amount of phase shift of the phase shifter, the combiner for combining the output of the reference sub-array antenna and the output of the phase shifter, and the respective sub-array antennas are maintained in parallel relationship based on the phase difference. With the attitude control, the normal direction of the sub-array antenna is changed to change the elevation direction of the antenna. And averaging means for calculating an average value of the phase differences detected by the phase difference detecting means, and second control means for controlling the drive of the elevation direction driving means so that the calculated phase difference average value becomes zero. And a tracking antenna device. 2. The antenna according to claim 1, wherein the elevation direction driving means includes: a motor that outputs a rotational force; a ball screw means that converts the rotational force output by the motor into a linear motion; and a ball screw means. And a linear rotation conversion means for converting the linear motion that is the output of the above into the rotational motion in the elevation direction of the antenna.