JPH01303903A - Method and apparatus for controlling attitude of reception antenna - Google Patents

Abstract

PURPOSE:To detect the incoming direction of radio waves from the phase difference between the signals received by two antennas and to allow to drive plural antennas separately by shifting the phase of the reception signal of one antenna by a phase corresponding to the distance between the radiating points of these antennas projected on an optional straight line in parallel with the become of the antennas. CONSTITUTION:The distance between projecting points in case of projecting substantial beam radiation points of the 1st and 2nd reception antennas on an optional straight line in parallel with each beam is represented as a vertical distance Lphi' between antennas 41 and 43. Thus, the reception signal of the antenna 41 is shifted by a phase corresponding to the distance Lphi', and when the phase difference of the reception signals is made zero with the direction of each antenna beam coincident with the incoming direction of the radio wave, the phase difference of the reception signal of the antenna 4a after the shift and the reception signal of the antenna 43 is caused by the deviation between the direction of each antenna beam and the incoming direction of the radio wave. That is, the incoming direction of the radio wave is detected correctly depending on the phase difference of the signals received by the 1st and 2nd reception antennas whose attitude is separately varied thereby controlling the attitude of each antenna.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to attitude control of a receiving antenna, and for example, to satellite tracking when receiving satellite broadcasting on a moving body such as a car.

[Prior art]

Since the realization of satellite communications, there has been a trend to receive radio waves from satellites not only in fixed buildings but also in mobile objects such as cars, but in order to receive weak radio waves from satellites, high Since a gain antenna, that is, an antenna with sharp directivity is used, attitude control of the antenna is required.

One of them is a satellite communication antenna device disclosed in Japanese Patent Publication No. 61-28244. Simply put, this device has a communication antenna and rate gyro installed on a flywheel-type stabilizer, and maintains the initially set antenna attitude in the communication direction, using so-called passive control. There is.

However, the high-gain antenna for receiving weak radio waves from satellites is relatively large and heavy. is required. For this reason, it is not very suitable for installation in small moving objects such as automobiles.

Separately, in parallel with reception, the direction of arrival of radio waves is detected and the satellite is tracked. There is so-called active control. In this case, the antenna attitude can be changed every time the arrival direction of the radio waves changes, so a flywheel is not needed.
The device itself can be downsized.

One type of active control is a simultaneous roving method that uses a plurality of antennas to detect the direction of arrival of radio waves from differences in the reception conditions of each antenna and performs attitude control.

[Problems with conventional technology]

Differences in reception conditions appear as level differences and phase differences between the signals received by each antenna, but the former largely depends on the electrical characteristics of each antenna and signal processing circuit, and the latter depends on the physical relationship (location) of each antenna. ), so
The latter method is effective for detecting the arrival direction of radio waves.

By the way, in this simultaneous roving method, when each antenna is separate, it is not possible to detect the arrival direction of the radio wave based on the phase difference between the received signals of each antenna.

This will be explained with reference to FIGS. 3a and 3b. However, these drawings are prepared for explaining the embodiments, and the explanation here should be considered separately from the embodiments described later.

FIG. 3a shows a model in which the antennas 41 and 42 rotate together around the rotation axis 13', the broken lines indicate the beams of each antenna, and the dashed-dotted lines indicate radio waves. In this case, the angle O between each antenna beam and the radio wave is the same as the angle θ' between the straight line connecting the centers of each antenna and the radio wave surface (perpendicular to the direction of travel), and the rotation around the rotation axis 13' Change. In other words, the phase difference between the received signal of the antenna 41 and the received signal of the antenna 42 is caused by the distance difference Lθ represented by Qθ・sinθ (Qθ is
2). Therefore, by detecting the phase difference between the received signals of the antennas 41 and 42, it is possible to detect the angle O1 between each antenna beam and the radio waves, that is, the relative direction of arrival of the radio waves.

On the other hand, FIG. 3b shows a model in which the antenna beams are held parallel, but the antenna 41 and the antenna 43 rotate separately around the rotation axis 111' and 121', respectively. □In this case, the angle φ between each antenna beam and the radio wave changes as each antenna rotates, but the angle φ′ between the radio wave surface and the straight line connecting the centers of each antenna remains constant regardless of the rotation of each antenna. . In other words, even if the phase difference between the signals received by each antenna is detected, the arrival direction of the radio waves cannot be detected.

[Purpose of the invention]

The present invention provides antenna attitude control technology that accurately detects the arrival direction of radio waves based on the phase difference between signals received by each antenna and controls the attitude of each antenna even when the attitude of multiple antennas is changed separately. The purpose is to provide.

[Structure of the invention]

In order to achieve the above object, the present invention includes a first receiving antenna whose attitude can be freely changed in a first direction;
When a second receiving antenna whose attitude can be freely changed in a second direction similar to the direction is driven with each beam kept parallel and directed in the direction of the radio wave source, the actual beam radiation point of the first receiving antenna is And the phase of the received signal of the first receiving antenna is adjusted by the phase corresponding to the distance between each projected point when the substantial beam radiation points of the second receiving antenna are projected onto an arbitrary straight line parallel to each beam. The direction of the radio wave source is determined based on the phase difference between the received signal of the first receiving antenna and the received signal of the second receiving antenna after the shift, and the postures of the first and second receiving antennas are set. .

[Effect]

Please refer to FIG. 3C for the operation of the present invention.

This drawing is an enlarged version of the above-mentioned FIG. 3b, but as before, the description here should be considered separately from the description of the embodiments to be described later.

In this case, 1. In the present invention, when the substantial beam radiation point of the first receiving antenna and the substantial beam radiation point of the second receiving antenna are projected onto an arbitrary straight line parallel to each beam, The distance between each projection point is the antenna 41
The vertical distance between the antenna 43 and the antenna 43 is shown as Lψ'. Now, if we consider the case where the angle φ between each antenna beam and the radio wave is zero, that is, the direction of each antenna beam matches the arrival direction of the radio wave, then the position of the received signal of antenna 41 and the received signal of antenna 43 is The phase difference is controlled by this vertical distance Lφ'. Therefore, the received signal of the antenna 41.

If the phase is shifted by the phase corresponding to this vertical distance 11EiLφ'' and the phase difference of each received signal is set to zero when the direction of each antenna beam matches the arrival direction of the radio wave, then the antennas 41 and 43 are aligned in the same straight line. (plane), and the phase difference between the received signal of the antenna 41 and the received signal of the antenna 43 after the shift is caused by the deviation between the direction of each antenna beam and the direction of arrival of the radio wave. Become.

That is, for the received signal of the first receiving antenna.

By applying the phase shift as described above, the first part changes its posture separately. It becomes possible to correctly detect the direction of arrival of radio waves based on the phase difference between the signals received at the second receiving antenna, and to control the attitude of each antenna.

This means that each antenna can be driven separately, which reduces the inertia of the movable parts.

This is extremely advantageous for downsizing the device. In particular, the effect is remarkable when a planar antenna is used instead of a three-dimensional antenna.

Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

〔Example〕

FIG. 1a and FIG. 1b show the configuration of the mechanical system of a car-mounted satellite broadcasting receiving system that implements the present invention as an example.
Figure a shows the configurations of the control system and signal processing system. This system tracks broadcast satellites using a modified simultaneous roving method using four planar antennas and a gyro, receives satellite broadcasts, and outputs video and audio to a television set installed in the car.

Each part will be explained in detail below.

First, please refer to Figures 1a and 1b.

The mechanical system maintains the beams of each planar antenna parallel and adjusts the azimuthal (azimuth) and elevation (azimuth) angles.
The support mechanism can be roughly divided into 1. It is divided into an azimuth drive mechanism 2 and an elevation drive mechanism 3.

The support mechanism 1 includes an antenna carriage 11.12. Turntable 1
3. The main components are a fixing table 14 and a pace 15.

The antenna carriages 11 and 12 are elongated rectangular flat plates having the same shape, and shafts 111 and 121 are fixed to the back surfaces of each of the antenna carriages 11 and 12 along the center line in the elongated direction. Each of these carriages is equipped with a planar antenna, a signal processing circuit, a gyro, etc. (described later).

The rotating table 13 has a horizontal arm 1319 rotating shafts 132 and 2
It has two vertical arms 133,134. Rotating shaft 132
is fixed to the center of the horizontal arm 131 in a vertically downward direction, and vertical arms 133 and 134 are integrally molded at both ends of the horizontal arm 131 in a vertically upward direction. Vertical arms 133 and 134 are identical.

At each opposing end, a shaft 111 fixed to the antenna carriage 11 or a shaft 121 fixed to the antenna carriage 12 is pivoted in parallel.

In this, as shown in FIG. 1b, the shaft 111
is supported higher than fill1121.

The fixed table 14 is fixed on the base 15 and pivotally supports the rotary table 13. A thrust bearing 141 is inserted between the rotating table 13 and the fixed table 14. Note that the base 15 is fixed to the roof of the automobile.

The azimuth drive mechanism 2 includes an azimuth motor 21. It consists of an hourglass-shaped worm 22 and a wheel gear (not shown). The azimuth motor 21 is fixed to the fixed base 14,
A drum-shaped worm 22 is fixed to the output shaft. A wheel gear (not shown) is fixed to the rotating shaft 132 of the rotating table 13 and meshes with the hourglass-shaped worm 22. That is, the rotation of the output shaft of the azimuth motor 21 is transmitted to the rotating shaft 132 via the hourglass-shaped worm 22 and the wheel gear, thereby rotating the rotating table 13. In this embodiment, this configuration allows rotation of the rotary table 13 at a maximum speed of approximately 180°/sec.

The elevation drive mechanism 3 includes an elevation motor 3
1. Drum-shaped worm 32. It consists of a fan-shaped wheel 33, links 34 & 35, etc. Elevation motor 31
is fixed to a vertical arm 133 of the rotary table 13, and an hourglass-shaped worm 32 is fixed to its output shaft. The fan-shaped wheel 33 is fixed to the shaft 121 of the antenna carriage 12 and meshes with the hourglass-shaped worm 32. Links 34 and 35 connect respective ends of axis 111 of antenna carriage 11 and axis 121 of antenna carriage 12, respectively. In other words, the rotation of the output shaft of the elevation motor 31 is caused by the rotation of the output shaft of the elevation motor 31.
3 to the axis 121 of the antenna carriage 12 and further via links 34 and 35 to the axis 111 of the antenna carriage 11, causing the antenna carriages 11 and 12 to rotate simultaneously. In this embodiment, this configuration allows rotation of the antenna carriages 11 and 12 at a maximum speed of approximately 120'/see. However, this rotation is limited to a range of ±30° around the attitude in which the antenna beam is directed upward at 35° with respect to the base 15.

Note that each element described above is covered by a radome RD with a cooling fan.

Please now refer to Figure 2a.

The signal processing system includes antenna group 4. BS converter group 5. B
S tuner group 6. The main components are an in-phase combining circuit group 7 and a television set 8, which combine the radio waves received by the antenna group 4 and output it to the television set 8, and also correct the error between the direction of the broadcasting satellite and the pointing direction of the antenna beam. To detect.

Antenna group 4 includes four planar antennas 41.42°43
and 44. Of these, planar antennas 41 and 42 are mounted on the antenna carriage 11,
Planar antennas 43 and 44 are attached to the antenna carriage 12
It is installed in. Each of the planar antennas has the same specifications, and each has a main beam with an offset angle (deviation angle from the normal) of about 35° and a half-power angle of about 7° at a working frequency of about 12 Gllz. The main beams of each planar antenna are maintained parallel by a mechanical system, and the azimuth directivity angle is updated integrally by the azimuth drive mechanism 2, and the elevation drive iFl+
Mechanism 3 integrally updates the elevation directivity angle.

The BS converter group 5 includes two BS converters 51 & 52° mounted on the antenna carriage 11 and two BS converters mounted on the antenna carriage 12.
Contains converters 53 & 54. BS converter 51
The input of the BS converter 52 is connected to the feeding point of the planar antenna 41, the input of the BS converter 52 is connected to the vi point of the planar antenna 42, the input of the BS converter 53 is connected to the feeding point of the planar antenna 43,
The input of the converter 54 is connected to the feeding point of the planar antenna 44,
Each BS converter converts the approximately 12 GIIz signal received by the corresponding planar antenna into approximately 1
, converted to a 3GHz signal.

The BS tuner group 6 includes BS tuners 61 & 62 mounted on the antenna carriage 11, BS tuners 63 & 64 mounted on the antenna carriage 12, and a synthesizer 65. Each BS tuner converts a signal of approximately 1.3 (Jz) converted by a BS converter 51, 52, 53 or 54 into an intermediate frequency signal of approximately 403 MHz using a local oscillation signal provided from a synthesizer 65. The signal that controls the oscillation frequency of the synthesizer 65 is transmitted through a slip ring (in the figure, sp-
(delimited by the sp line) by a channel selector 84 of the television set 8, which will be described below.

The in-phase synthesis circuit group 7 includes three in-phase synthesis circuit blocks 1゜72.
& 75. It includes a phase shift circuit 73 and a D/A converter 74. Of these, the in-phase synthesis circuit 712, the phase shift circuit 73, and the D/A converter 74 are mounted on the antenna carriage 11, and the in-phase synthesis circuits 72 and 7 are mounted on the antenna carriage 11.
5 is mounted on the antenna carriage 12.

Here, before explaining the details of each circuit, let us explain the details of Figures 3a and 3.
The significance of in-phase synthesis will be explained with reference to Figure b and Figure 3c. However, in these drawings, each planar antenna is a linear antenna with no offset angle on the valve chamber of the drawing, and each antenna beam is indicated by a broken line.
A radio wave is shown by a one-dot chain line, and a radio wave surface is shown by a two-dot chain line.

FIG. 3a is a model of the planar antennas 41 and 42, focusing on the azimuth direction. These antennas are on the same straight line and rotate together around a rotation axis 13' (which can be thought of as a symbol of the rotating table 13). In other words, the angle 0 between each antenna beam and the radio wave (hereinafter referred to as azimuth declination angle) is the same as the angle θ' (hereinafter referred to as azimuth phase angle) between the straight line connecting the center of each antenna and the radio wave surface, and rotation It changes by rotation around the axis 13'.

In this case, consider a planar projection image in which a broadcasting satellite exists in the beam direction direction of antennas 41 and 42),
If the azimuth declination angle θ and the azimuth phase angle θ' are in the range of center distance between antennas 41 and 42).

This distance difference Lθ is very small compared to the distance between each antenna and the broadcasting satellite, so it does not affect the strength of the radio waves from the broadcasting satellite, but since radio waves have periodicity, It has a large effect on the phase difference. In other words, antenna 4
If the radio waves arriving at antenna 42 are denoted by COSωL,
The radio waves arriving at .

Since it is delayed by Lθ/C time, cosω(t
-Lθ/c) =cos(ωt-2tc・QB・5inO/λ)—・
It is expressed as 1φ(1). However, ω is the angular velocity of the radio wave,
C is the propagation speed and λ is the wavelength.

If the received signals from each antenna are combined without removing this phase difference, that is, 2π·QB·sin O/λ, they will interfere with each other. Therefore, the in-phase combining circuit 71 removes the phase difference between the received signals of the antennas 41 and 42 and combines them.
An in-phase combining circuit 72 removes the phase difference between the signals received by the antennas 43 and 44 and combines them.

Furthermore, since the 1 phase difference 2π・QB・sLnθlλ uniquely corresponds to the azimuth deviation angle 0, it is extracted in the in-phase synthesis circuit 72, converted into digital data in the A/D converter ADI, and then passed through a slip ring to be described later. It is given to the system controller 91 to

FIG. 3b is a model of the planar antennas 41 and 43 focusing on the elevation direction, each of which maintains parallelism and has a different rotation axis 111' or 121.
' (consider the symbols of axes 111 and 121, respectively). In other words, the angle φ between each antenna beam and the radio wave (hereinafter referred to as the elevation declination angle) changes depending on the rotation of each antenna, but the angle between the radio wave surface and the straight line connecting the centers of each antenna (hereinafter referred to as the elevation reference line) φ' (hereinafter referred to as the elevation phase angle) remains constant regardless of the rotation of each antenna.

In this case, considering the same as above, the distance difference between the antenna 41 and the antenna 43 with respect to the broadcasting satellite LφC=Qφ・
If the phase difference caused by sinφ′: Qφ is the distance between antenna centers is removed, the received signals of these antennas can be combined without interference, but the elevation phase angle φ′ is due to the rotation of each antenna. Therefore, the elevation deviation φ cannot be determined based on the phase difference.

On the other hand, if we consider the case where a broadcasting satellite exists in the beam orientation direction of antennas 41 and 43 (consider a planar projection image), the distance between antenna 43 and the broadcasting satellite is smaller than the distance between antenna 41 and the broadcasting satellite. Vertical distance L between antennas
It becomes longer by φ'. This vertical path aLφ' is defined by the deflection angle (upward is positive: hereinafter referred to as elevation angle) E of each antenna with respect to the elevation reference line, as shown in FIG. 3c.
If Q is defined, it is expressed as Qφ·5inEfl, and the phase delay of the signal received by the antenna 43 with respect to the signal received by the antenna 41 is expressed as 2π·Qφ·5inEQ/λ.

In other words, the received signal of the antenna 41 has a phase difference of 2π·Q.
If the signal is delayed by φ·5inEI2/λ, it can be said that the phase difference between the delayed signal received by the antenna 41 and the signal received by the antenna 43 is caused by the elevation angle φ. Therefore, in the phase shift circuit 73, the in-phase combined output of the antennas 41 and 42 is changed to 2π·Qψ
- After delaying by 5 in EQ/λ, the in-phase combining circuit 75 performs in-phase combining with the in-phase combining outputs of the antennas 43 and 44, extracts information regarding the elevation declination angle φ, and converts it digitally in the A/D converter ADI. The signal is supplied to a system controller 91, which will be described later, via a slip ring.

The details of each circuit will be explained below.

The in-phase synthesis circuit 71 is composed of a plurality of splitters, mixers, low-pass filters, combiners, etc., as shown in FIG. 2b.

Terminal A is given an intermediate frequency signal based on the signal received by antenna 41 from BS tuner 61, and terminal B is given an intermediate frequency signal based on the signal received by antenna 42 from BS tuner 62. The former is distributed by splitter 711 to amplifier 712 and splitter 713, and further distributed by splitter 713 to mixers 714 and 715, and the latter is distributed by 90' phase shift splitter 716 to splitters 717 and 718, and further , splitters 717 and 718 to mixers 714, 715,
71B and 71C. In this case, 906 phase shift splitter 716 is 906 phase shift splitter 716 relative to splitter 718.
Since the phase-shifted input signal is distributed, the signal distributed to the mixers 715 and 71C via the splitter 718 is based on the received signal of the antenna 42 (a signal obtained by shifting the intermediate frequency signal by 90 degrees). .

As mentioned above, the BS tuner 61 applied to terminal A
There is a phase shift between the intermediate frequency signal from the BS tuner 62 and the intermediate frequency signal from the BS tuner 62 applied across the terminal due to the arrangement of the antennas 41 and 42. now,
If the intermediate frequency signal from the BS tuner 61 is cosω and the phase difference is e, the intermediate frequency signal from the BS tuner 62 is expressed as cos (ωt, -e), and the splitter 7
The signal distributed to mixers 715 and 71C via 18 is expressed as 15 inches (ω is 10).

The mixer 714 uses the signal applied through the splitter 713 and the signal applied through the splitter 717 to perform an operation of cosω and cos (ω is one θ). This operation is expressed as cos θ + cos (2 ω and - e) (the arithmetic coefficients are omitted as they are meaningless:
(see below), the cos e component signal can be extracted by removing harmonic components in the low-pass filter 719. This signal is given to mixer 7113,
Here, the calculation cose-cos (ωshi-e) is performed.

The mixer 715 uses the signal applied via the splitter 713 and the signal applied via the splitter 718 to perform the calculation -Cos(11j-sin(ω and -e). sin (2ω
As shown in (10), by removing the harmonic components in the low-pass filter 71A, the signal of the sine component can be extracted. This signal is given to the mixer 71C, where an operation of -5in (lsin (ω + - θ)) is performed.

Combiner 71D adds the output of mixer 71B and the output of mixer 71C.

cosθ・cos(ωshi−e) −5inθ−5in(
The calculation ωt−θ) is performed. As a result, the signal of the cosω component can be extracted, and after level adjustment is performed in the amplifier 71H, it is combined with the output of the amplifier 712 in the combiner 71F.

In addition, in Fig. 2b, the output of the combiner 71F is
cosω, but this coefficient has an arithmetic meaning (
In other words, it should be understood that this does not mean that the two signals, that is, the respective intermediate frequency signals from the BS tuners 61 and 62, are synthesized in phase (hereinafter, the intermediate frequency signals), rather than the one having an amplitude component).

The output signal 2cosωt of the in-phase combining circuit 71 is applied to the terminal X' of the phase shift circuit 73.

The phase shift circuit 73 includes 90° splitters 731 & 732 . as shown in FIG. 2e. Mixer 733 & 73
4 and a combiner 735, the in-phase synthesis circuit 71
The phase of the output signal 2cosω is determined by the phase difference 2π・Qφ・ginEQ based on the vertical distance Lφ′ between the antennas.
/λ (hereinafter abbreviated as E).

That is, the terminal P is given a shift signal cosε corresponding to the cosine of the phase difference ε. This signal is a DC voltage signal obtained by converting digital data, which will be described later, by a system controller 91 in association with the antenna elevation angle EQ at that time, into an analog signal by the D/A converter 74.

The signal 2cosωt applied to the terminal

The mixer 733 is supplied with signals without a phase shift, so the calculation 2cosωt-Co5ε is performed, and the mixer 734 is supplied with signals with a phase shift, so the calculation 2sinωt-5in i is performed. It is done. By adding these output signals in the combiner 735, a signal cos (ω and −ε) obtained by shifting the output signal 2cosωt of the in-phase combining circuit 71 by a phase difference ε is obtained from the output end thereof. This signal is given to the in-phase combining circuit 75.

On the other hand, the in-phase synthesis circuit 72 synthesizes the respective intermediate frequency signals from the BS tuners 63 and 64 in the same phase in exactly the same manner as the in-phase synthesis circuit 71. This configuration is the same as that of the in-phase synthesis circuit 71, except that a low-pass filter 72G is provided for further discussion, as shown in FIG. 2C. This low-pass filter 72G extracts a DC signal corresponding to the phase difference between the intermediate frequency signal outputted by the BS tuner 63 and the intermediate frequency signal outputted by the BS tuner 64.

As described above, there is a phase shift between the intermediate frequency signal output by the BS tuner 61 and the intermediate frequency signal output by the BS tuner 63 due to the arrangement of the antennas 41 and 43. Now, following the above, BS tuner 6
If the intermediate frequency signal outputted by the BS tuner 63 is cosωt and the phase difference is Φ, then the intermediate frequency signal outputted from the BS tuner 63 is expressed as cos(ωL−Φ). Further, as described above, if the phase shift caused by the arrangement of the antennas 43 and 44 is e, the intermediate frequency signal from the BS tuner 64 is expressed as cos (ωL-Φ-e). Therefore, the signal processing process here is as shown by the equation shown in FIG.
It is equivalent to replacing ωL in the explanation of 1 with (ωt-Φ), and the BS tuner 6
A signal 2cos(ωL-Φ) is obtained by combining the respective intermediate frequency signals from 3 and 64 in phase (see above for details).

Further, from the low-pass filter 72G, the output signal of the mixer 726, -cos(ωt-Φ)・5in(ωt-Φ
-e) Azimuth error voltage Vθ with higher harmonic voltage removed,
That is, the sin θ component is extracted. The phase difference θ that gives this azimuth error voltage Vθ is the phase difference between the received signal of the antenna 41 and the received signal of the antenna 42, or the phase difference of the received signal of the antenna 43 and the received signal of the antenna 44, and is the phase difference between the received signal of the antenna 43 and the received signal of the antenna 44, and Phase difference 2π・Qθ・s used in the explanation
The same is true for inθ/λ.

The output signal 2cos (ωL-Φ) of the in-phase synthesis circuit 72 is given to the in-phase synthesis circuit 75.

The configuration of the in-phase synthesis circuit 75 is the same as that of the in-phase synthesis circuit 72 as shown in FIG. 2d, and in this case,
The output signal 2 cos (ω and −ε
), and the output signal 2cos(ω and Φ
) and a low-pass filter 75G.
Therefore, the phase difference between the received signal of the antenna 41 and the received signal of the antenna 43, or the phase difference Φ between the received signal of the antenna 42 and the received signal of the antenna 44, and the phase difference of the received signal of the antenna 41,
The vertical distance fiLψ' between the antenna 43 and the antenna 43, or the straight distance Lφ between the received J signal of the antenna 42 and the antenna 44
The elevation error voltage Vψ corresponding to the difference from the phase difference ε based on ', that is, the sin (Φ-ε) component is extracted.

The signal processing process performed in this circuit is as shown by the equation in FIG.
)), and is equivalent to B from combiner 75F.
The output signals of the S tuners 51, 52, 53 and 54 are in-phase combined to obtain a signal 4cos (ω and -ε) (see above for details).

Referring again to FIG. 2a, the output of the in-phase synthesis circuit 75 is provided to the television set 8 via a non-contact type coupling transformer Trs.

The television set 8 includes a demodulation circuit 81 . CRT82
, speaker 83. It includes a channel selector 84, a main switch 85, etc., and is installed inside the vehicle.

The demodulation circuit 81 demodulates the signal given from the in-phase synthesis circuit 75 and outputs an image to the CRT 82 and audio to the speaker 83, respectively. Further, the AGC signal used in automatic gain adjustment is branched and given to the system controller 91 via the A/D converter AD2.

As described above, the channel selector 84 is manually operated to set the oscillation frequency of the synthesizer 65, and the main switch 85 is manually operated to energize the power supply unit D. The power supply unit D supplies a predetermined voltage to each component, and also energizes a ventilation cooling fan E installed in the radome RD.

The control system includes a system control unit 9°, an azimuth drive control unit A, an elevation drive control unit B, and various sensors.

The system control unit 9 includes a system controller 91 and an operation board 92, and is installed inside the vehicle. The system controller 91 executes a search and tracking of the broadcasting satellite according to an operator's command from the operation board 92, and the details thereof will be described later.

The azimuth drive control unit A includes an azimuth servo controller 1-roller A1 that controls the energization of the azimuth motor 21, a timing generator A2 coupled to the azimuth motor 21, and the like.

The azimuth servo controller AI is based on the current value (positive or negative) corresponding to the rotation (positive or reverse) of the azimuth motor 21 detected by the timing generator A2 and the current reference value (positive or negative) given by the system controller 91.
The azimuth motor 21 is energized and controlled.

Elevation drive control unit B includes an elevation servo controller B1 and an elevation motor 3 that energize and control the elevation motor 3.
The timing generator 82 and the like are coupled to the timing generator 82 and the like.

The elevation servo controller B1 controls the elevation motor 3I detected by the timing generator B2.
The current value (positive/negative) corresponding to the rotation (positive/reverse) of the , and the current reference value (positive/negative) given by the system controller 91.
Based on this, the elevation motor 31 is energized and controlled.

The main sensors include gyros C1 & C2, rotary encoders C3 & C4, and limit switches SW.
u & Sνd, as well as current sensor and angular velocity sensor (
(not shown).

Gyros CI and C2 are mounted on the antenna carriage 12. Gyro C1 has a degree of freedom in the azimuth direction, and gyro C2 has two degrees of freedom in the elevation direction, and each generates a voltage signal according to the angular velocity of deviation in the azimuth or elevation direction due to changes in attitude or movement of the car, etc. Output. These detection signals are digitally converted by the A/D converter ADI and then provided to the system controller 91 via a slip ring.

The rotary encoder C3 is coupled to the azimuth motor 21 and detects the rotation angle of the rotary table 13, that is, the azimuth angle. In this case, angle detection is performed with clockwise rotation as positive, based on the attitude in which the antenna beam faces directly in the direction of travel of the vehicle.

The rotary encoder C4 is connected to the elevation motor 31
and the antenna carriages 11 and 12
Detect the rotation angle, that is, the elevation angle. In this case, as mentioned above, the elevation reference line (the straight line connecting the centers of antennas 41 and 43 or 42 and 44)
Detect the declination angle with respect to the upper direction as positive.

Limit switches SVu and SVd are both engaged with the elevation drive mechanism 3, and detect the upper and lower limits of the antenna beam's elevation angle.

In this embodiment, as described above, the upper limit is a posture in which the antenna beam is directed upward by 65'' with respect to the pace 15, and the lower limit is a posture in which the antenna beam is directed upward by 5 degrees.

Although not shown, a current sensor and an angular velocity sensor are provided in the azimuth servo controller Al and the elevation servo controller Bl, respectively. These sensors detect the energizing current and rotational angular velocity of the azimuth motor 21 or the elevation motor 31, respectively, as voltage signals. These detection signals are given to the system controller 91 via the A/D converter AD3.

Here, the antennas 41 to 41 executed in the system of this embodiment
44 will be explained with reference to the block diagram shown in FIG. 4a. This block diagram is
This is shown regarding attitude control in the azimuth direction.
Since the attitude control in the elevation direction is exactly the same, illustrations and explanations will be omitted.

Now, the reference azimuth angle ΔZQ for attitude control in the azimuth direction
is given, and the motor 21 is energized by the current Dθ after performing predetermined compensation. Block FA is motor 2
1, where RA represents the armature resistance and tA represents the electrical time constant.

Due to this energization, a current of 1.9 flows through the armature circuit of the motor 21, and a torque proportional to the armature current ■θ is generated on the output shaft of the motor 21. That is, block FB is a proportional element, and constant KB indicates a torque constant. This torque is caused by torque disturbance T I due to movement of the car, etc.
Receive L.

The torque generated in the motor 21 rotates the rotary table 13 and updates the azimuth angle of the antenna beam. Its angular velocity Qθ
is proportional to the integral value of torque, and the updated azimuth angle is further proportional to the integral value. Block FC indicates the former function, and block ["D indicates the latter function. Note that Jl is
This is a proportionality constant due to the inertia of the azimuth drive mechanism 2, rotating table 13, etc.

The updated pointing direction of the antenna beam deviates from the actual direction of the broadcasting satellite due to angular velocity disturbance AZL caused by movement of a car or the like.

As described above, the antenna 4 is controlled by the current Dθ set based on the reference azimuth angle Az□ for attitude control in the azimuth direction.
The attitude control of Nos. 1 to 44 deviates from the expected results due to disturbances such as electrical loss and movement of the automobile. Therefore, in this embodiment, an angle control loop, a speed control loop, and a current control loop are provided.

The angle control loop determines the reference angle AZ based on the difference in azimuth angle between the pointing direction of the antenna beam detected in the in-phase synthesis circuit 72 and the direction of the broadcasting satellite, that is, the azimuth declination θ.
(However, as mentioned above, disturbances are superimposed on the movement of the antenna beam in the pointing direction, so from this azimuth declination 0, the azimuth angle Az detected by the rotary encoder C3 is By subtracting only the disturbance, the reference angle A z , ) is compensated for.

Blocks F1 and F2 are proportional elements, Kl, 2
indicates the constant of proportionality.

By the way, the azimuth declination angle θ cannot be obtained when there is no reception by the antennas 41 to 44. Therefore, in that case, instead of the azimuth declination O, the angular velocity Gφ (
(hereinafter referred to as gyro data in the azimuth direction) is integrated and used. Block F3 shows this integral, and block F3
11 and F12 indicate these switches.

A velocity control loop compensates for angular velocity disturbances. In this case as well, by subtracting the angular velocity QO of the motor 21 detected by the angular velocity sensor from the angular velocity in the azimuth direction of the antennas 41 to 44 including the angular velocity disturbance, that is, the gyro data Gθ in the azimuth direction by the gyro C1. , only the angular velocity disturbance is extracted, thereby compensating for Z2. Blocks F5 and F6 are proportional elements, and
and 6 is its proportionality constant. However, in this case,
When the reception level has decreased and the reference angle Azo has already been compensated for using the gyro data Gθ, the gyro data Gθ is not fed back again.

This switching is performed in block F61.

The current control loop compensates for electrical loss in the motor 21 and the energizing circuit using the energizing current ■θ of the motor 21 detected by the current sensor. Block F4 is a proportional element, K
4 is its proportionality constant.

In this control process, when the reference angle A z O is compensated for angular disturbance by the angle control loop to obtain 71, proportional-integral compensation (71 is applied to the proportional constant) is performed in block F7.
．． A time constant t7) is applied to obtain Z2, and 73 is obtained by further performing compensation for angular velocity disturbance by the speed control loop and compensation for electrical loss by the current control loop. This value is converted into a current value corresponding to the updated angle in the proportional block F8 (proportionality constant: 8), and the motor 21 is energized. However, since the device of this embodiment is installed in an automobile, current limitation is performed in block F9 in order to protect the power supply.
The motor 21 is energized by the limited current Dθ. This allows proportional-integral compensation (
A current limit will be added to the angle control loop including F7), but since the speed control loop and current control loop are configured inside it, a windup phenomenon will not occur due to the combination of proportional-integral compensation and current limit. do not have.

In other words, in this embodiment, since the speed control loop and the current control loop are configured inside the angle control loop, it is possible to realize high-speed response control without offset, and to protect the power supply without causing wind-up development. There is.

The above control processing is performed by the system controller 91. The control operation of the system controller 91 will be described below with reference to the flowcharts shown in FIGS. 5a and 5b.

When the main switch 85 is turned on and a predetermined voltage is supplied to each part, the system controller 91 outputs Sl (indicates the number attached to the star graph in the flowchart; hereinafter the same meaning).
Initialize memory, registers, flags, etc. at
In S2, the search range for broadcasting satellites is initialized. As will become clear from the explanation given later, this search is a so-called helical scan, and here, the register EQd
The minimum and maximum values of the elevation angle are stored in EI2u and EI2u, respectively, and a helical scan of the entire area is set.

83 to S5 is a loop waiting for input from the operation board 92. In this loop, when the data of the area in which the car is traveling is inputted, the elevation angle of the broadcasting satellite can be specified to some extent, and a corresponding search range is set in S4. Thereafter, when a start instruction is input from the operation board 92, the loop is broken and the process proceeds to S6.

In S6, the elevation angles of the antennas 41 to 44 are set to the search start angle EQd (same as the value 2 or less of the register EQd). In this case, while monitoring the novation angle Efl detected by the rotary encoder C4, an instruction is given to the old elevation servo controller to energize the elevation motor 31.
If it matches Qd, it instructs deactivation.

In S8, the reception level L (AG
C signal) is read, it is compared with the minimum reception level L min in S9. At this time, if the reception level L is below the minimum reception level L win, a search flag is set in S13, and the azimuth energizing current Dθ is set to a high value and the elevation energizing current Dφ is set to a low value in S14. The signal is output to the azimuth servo controller A1 and the old elevation servo controller to instruct the azimuth motor 21 and the elevation 31 to be energized.

As a result, the antennas 41 to 44 are continuously rotated at high speed in the azimuth direction and changed in attitude at low speed in the elevation direction, so that the antenna beams draw a spiral. During this time, the reception level L is continuously monitored in a loop consisting of 87 to S14.

If the elevation angle EQ exceeds the search end angle EQu before the reception level exceeds the minimum reception level L win,
The process exits the loop from S14, displays unreceivable on the operation board 92 in S15, instructs each servo controller to stop in 816, and ends the search process, and then returns to S1.
In step 7, the search flag is reset and the process returns to S3. If a stop instruction is input from the operation board 92 while the search process is being executed, the process exits the loop from S7 and proceeds to 516, where the same process is performed.

If the reception level L exceeds the minimum reception level L win before the elevation angle EQ exceeds the search end angle EρU, the loop exits from S9, and in S19, each servo controller is instructed to stop, and the search process is ended, S2
The search flag is reset at 0.

In S21 and S22, the azimuth angle Az and elevation angle EQ at this time are read and stored as the reference azimuth angle and reference elevation angle in the registers A z (1 and EQO, respectively).

After this, in the loop consisting of S23 to S42, the fourth
Attitude control of the antennas 41 to 44 is performed according to the control loop shown in Figure a.

First, when the azimuth angle Az and the elevation angle Efl are read in S24, the antennas 41 and 43 provided by the elevation angle EQ are determined in S25.
The phase difference E due to the vertical path fiLφ' with the antennas 42 and 44 is read from the ROM table and output. This data is transferred to the D/A converter 7 as described above.
4 is converted into a voltage value and applied to a phase shift circuit 73, which shifts the combined received signal of antennas 41 and 43.

In S26, the reception level L is read, and 827 to S
In 29, if the value exceeds the minimum reception level L win, 1 is stored in the A register, and the minimum reception level L
If it is less than min, 0 is stored in the A register. The value of this A register is used for switching the control parameters described above.

In S30, the energizing current θ of the azimuth motor 21 and the energizing current Iφ of the elevation motor 31 are read, and in S31, the angular velocity Qθ of the azimuth motor 21 is read.
and the angular velocity Qφ of the elevation motor 31 are read, and in S32, the antennas 41 to 44 including the disturbance are read.
The angular velocity in the azimuth direction, that is, the gyro data Gθ
, and the angular velocity in the elevation direction of the antennas 41 to 44 including disturbances, that is, gyro data Gθ.

Furthermore, in S33, the azimuth error voltage Vθ (
= sin θ) and elevation error voltage Vφ (=s
in (Φ-ε)) and determines the azimuth declination angle θ and the elevation declination angle φ by referring to the ROM table.

In S34, the azimuth declination θ, the azimuth angle A z
1 azimuth direction gyro data G8. The control parameter Y1 in each feedback loop described above using the energizing current θ and the angular velocity Qθ of the azimuth motor 21
~I'm looking for Y6. In other words.

Azimuth angle 0 is multiplied by a constant Kl and stored in register Y1, azimuth angle Az is multiplied by a constant 2 and stored in register Y2, gyro data Gθ is integrated by the integration method and stored in register Y3, and attached. Multiply the current Iθ by a constant by 4 and store it in register Y4.

Multiply the angular velocity Qθ by a constant by 5 and store it in register Y5,
The gyro data Gθ is multiplied by a constant of 6 and stored in the register Y6.

In S35, first, the reference angle AZO is compensated for the angular disturbance by the angle control loop to obtain the above-mentioned Zl, and then the above-mentioned z2 is obtained by north-integrating it, and further,
After compensating for angular velocity disturbance by the speed control loop and compensating for electrical loss by the current control loop to obtain the above-mentioned Z3, convert it into the energizing current value of the motor 21 to obtain the above-mentioned z4. There is.

In this case, in compensation for angular disturbance, if the value to the register is 1, the difference between parameters Y1 and Y2 is set to the reference angle A.
In addition to zO, if the value to the register is 0, the difference between parameters Y3 and Y2 is added to the reference angle A z o (overline indicates negation).

In addition, compensation for angular velocity disturbance and electrical loss are performed simultaneously, and the proportional integral value Z2 of zl is obtained by the integration method.
If the value of register A is 1, then the difference between parameters Y6 and Y5 is added, and register A
If the value of is 0, only parameter Y5 is added.

In steps 336 to S40, the current limitation described above is performed. In this case, the value z obtained by converting the reference azimuth angle after various compensations into the energizing current value of the motor 21
The azimuth energizing current Dθ is set by adjusting 4 to a value that is greater than or equal to the maximum reverse rotation energizing current −Dθhi and less than or equal to the maximum forward rotation energizing current Dθh.

When the elevation energizing current Dψ is set in S41 using the same procedure as step 1 and above, in S42, the energizing currents Dθ and Dφ are output to the azimuth servo controller A1 and the elevation servo controller B1, and the azimuth motor 21 and Instructs to energize the elevation 31.

The above loop is repeated until a stop instruction is input from the operation board 92, and when the stop instruction is input, 3
The loop exits from 23 and proceeds to S43, where each servo controller is instructed to stop, the tracking process is ended, and S
Return to 3.

By the way, in the above attitude control, the proportional constant has a relationship of 2=-Kl between 1 and 2, and a proportional constant of 5 and 6 has a relationship of 6=-5. It has been found that the offset can be removed without performing proportional integral processing.

A block diagram 11 for posture control based on this is shown in FIG. 4b. Referring to FIG. 4b, not only the proportional integral processing shown in block F7 in the above-mentioned section 4a[g is omitted, but also the integral processing of the gyro data Gθ shown in block F3 is omitted. ing.

This is because the point of action of the angle control loop, speed control loop, and current control loop (
This is due to the fact that both parties agree on the point of providing compensation. Therefore, the only switching function is Fil, which greatly simplifies control.

Specifically, among the control operations of the system controller 91, the processing contents at 334 and S35 in the flow shown in FIG. 5b are simplified. That is, in S34, there is no need to calculate the control parameter Y3,
Moreover, in S34, Zl.

Instead of calculating Z2 and Z3.

Z3 is directly obtained by performing the calculation ΔzO+AY 1-Y2-Y4-Y5+Y6. Since there are no changes other than these, no new flowchart is shown.

In addition, in the above embodiment, each antenna 41°42,
Although 43 and 44 are constructed using planar antennas, the effects of the present invention will remain the same even if a three-dimensional antenna is used instead.

〔Effect of the invention〕

As explained above, in the present invention, when the posture of the first and second antennas is changed separately on the condition that each beam is kept parallel, the phase of the reception (ffi signal) of one antenna is changed. , the phase is shifted by the phase corresponding to the distance between the radiating points of each antenna projected on the tuning window straight line parallel to each beam, so the phase difference between the received signal after the shift and the received signal of the other antenna is Reflects the declination angle of the radio wave source with respect to the beam.

In other words, by applying this type of phase shift to the received signal of one antenna, it becomes possible to detect the arrival direction of the radio wave from the phase difference between the signals received by each antenna5. Since the antenna can be driven separately, the inertia of the movable part is reduced, which is extremely advantageous for downsizing the device. Further, as described in the description of the embodiment, when using a planar antenna, the three-dimensional operating range can be reduced by dividing it, so that its low profile property can be fully utilized.

[Brief explanation of the drawing]

FIG. 1a is a plan view showing the configuration of a mechanical system of an automobile-mounted satellite broadcast receiving system embodying the present invention as an example, and FIG. 1b is a front view thereof. FIG. 2a is a block diagram showing the configuration of the control system and signal processing system of the embodiment system, and FIG. 2b is a block diagram showing the configuration of the control system and signal processing system of the embodiment system. FIGS. 2c, 2d and 2e are block diagrams showing a portion thereof in detail. FIGS. 3a, 3b, and 3c are explanatory diagrams for explaining the principle of detecting the phase difference occurring in the received signal and the direction of the broadcasting satellite. FIG. 4a is a block diagram showing the operation of the embodiment system, and FIG. 4b is a block diagram showing a modification thereof. FIGS. 5a and 5b are flowcharts showing the operation of the system controller 9I shown in FIG. 2a. 1: Support mechanism (first and second support means) 11.12: Antenna carriage 13: Rotating table 14: Fixed table 15: Base 2: Azimuth drive mechanism 21: Azimuth motor 22: Drum-shaped worm 3: Elevation drive mechanism (Drive means) 31: Elevation motor 32: Drum-shaped worm 33: Fan-shaped wheel 34.35
: Link 4: Antenna group 41.42, 43, 44 : Planar antenna 41.42
: (1st receiving antenna) 43.44 : (2nd receiving antenna) 5: BS converter group 51.52, 53, 54: t3s converter 6: I
IS tuner group 61.62, 63, 64: [lS tuner 65: Synthesizer 7: In-phase synthesis circuit group 71.72: In-phase synthesis circuit 73: Phase shift circuit (phase shift means) 74: D
/A converter 75: In-phase synthesis circuit (second detection means) 8: Television set 81: Demodulation circuit 82: CRT 83: Speaker 84: Channel selector 85: Main switch 9 System control unit 91 System controller 92: Operation board A Near mast drive control unit A1: Azimuth servo controller A2: Timing generator B: Elevation drive control unit El
f Elevation servo controller B2: Timing generator B,! jl: (control means) CI, C2: gyro C3, C4: rotary encoder C4, 91: (first detection means) SWu, 5lld: limit switch D: fri source unit E: fan RD elm dome ADl, AD2. AD3: A/D converter Trs
：Non-contact coupling transformer

Claims (2)

[Claims] (1) Driving a first receiving antenna whose attitude can be changed in a first direction and a second receiving antenna whose attitude can be changed in a second direction similar to the first direction while keeping their respective beams parallel; When pointing in the direction of the radio wave source, when the substantial beam radiation point of the first receiving antenna and the substantial beam radiation point of the second receiving antenna are projected onto an arbitrary straight line parallel to each beam, The phase of the received signal of the first receiving antenna is shifted by the phase corresponding to the distance between each projection point, and the radio wave is transmitted based on the phase difference between the shifted received signal of the first receiving antenna and the received signal of the second receiving antenna. A receiving antenna attitude control method that determines the direction of a source and sets the attitudes of first and second receiving antennas. (2) A first receiving antenna and a second receiving antenna; first supporting means for supporting the first receiving antenna so that its attitude can be changed in a first direction; the second receiving antenna is separated from the first receiving antenna; , a second support means for supporting the second direction so as to be able to change its attitude in a second direction similar to the first direction; keeping the beam of the first receiving antenna and the beam of the second receiving antenna parallel;
Driving means for driving the first receiving antenna in the first direction and the second receiving antenna in the second direction; a substantial beam radiation point of the first receiving antenna, and a driving means for driving the second receiving antenna in the second direction; A first detection means for detecting the distance between each projected point when the substantial beam radiation points are projected onto an arbitrary straight line parallel to each beam; a phase of the received signal of the first receiving antenna; a phase shifter that shifts the phase by a phase corresponding to the distance; a second phase shifter that detects a phase difference between the received signal of the first receiving antenna after the phase shift and the received signal of the second receiving antenna;
An attitude control device for a receiving antenna, comprising: a detection unit; and a control unit that determines the direction of a radio wave source based on the phase difference and controls energization of the drive unit.