JPH05142322A - Satellite tracking receiver of antenna for moving body - Google Patents

Abstract

PURPOSE:To provide a simple and inexpensive satellite tracking receiver of an antenna for a moving body, which has sufficient responsiveness for frequent position change of the moving body. CONSTITUTION:A receiving signal from an antenna 53 is converted into a frequency signal by a frequency converter 54, and is sent to a level detector 55, and the level (DC) is detected. The level signal is given to a level change detection circuit 56, and +V or -V is selected by a switch 57 according to the level change, and an output signal omega is sent to an calculator 59. An angle velocity signal omegag from an angle velocity sensor 58 is input into a calculator 59, and a composite signal between omega and omegag is sent to a motor driving circuit 60, while a motor 52 is driven and controlled by the circuit through the composite signal, and the direction from the antenna 53 is tracked by a satellite.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a satellite tracking receiver for a mobile antenna, and more particularly, to a mobile object using an angular velocity sensor for detecting the angular velocity of the mobile object and a receiving level change detecting means. It relates to a configuration for effectively performing satellite tracking of the upper antenna.

[0002]

2. Description of the Related Art There is a phase monopulse system as one of satellite tracking systems for mobile antennas. First, the system will be described with reference to FIG. As shown in FIG. 6A, when the antennas 3 and 4 placed on the turntable 1 face perpendicularly to the direction of arrival of radio waves, the two antennas are at the same distance from the satellite, Both received signals are cos
(Ω ₀ t). On the other hand, as shown in FIG. 6B, when the antennas 3 and 4 are deviated from the arrival direction of the radio wave, a phase difference of ψ occurs due to the deviation of the distance from the satellite. As a result, the received signal of the antenna 3 is cos (ω ₀ t), the antenna 4
The received signal of is cos (ω ₀ t + ψ). The motor 2 is controlled by detecting this phase difference, and its method will be described.

A signal cos (ω ₀ t) received by the antenna 3 is converted into a signal cos (ω ₀ t) by the frequency converter 6, and similarly, cos (ω ₀ t + ψ) received by the antenna 4.
Is converted into a signal of cos (ω ₀ t + ψ) by the frequency converter 7. At this time, since the frequency signal from the VCO 5 input to the frequency converter is shared, the phase difference ψ is retained even after the frequency conversion.

When the output of the frequency converter 6 is passed through the 90 ° phase shifter 8, it becomes sin (ω ₁ t). This signal and the output cos (ω ₁ t + ψ) of the frequency converter 7 are sent to the phase comparator 9. When input, a high frequency component of sin (2ω ₁ t + ψ) and a DC signal of sin ψ are obtained. Since this DC signal has a DC value representing the phase difference, the low-pass filter (LPF) 10
To remove high frequency components.

Since the DC signal sin ψ corresponding to this phase difference changes as shown in FIG. 7 with respect to the shift ψ from the satellite,
Within the range of ± π, the signal of the control direction of the motor 2 is ± π
In the range of / 2, it can be used as a signal of the motor control speed. For this reason, the signal from the LPF 10 is fed to the amplifier 11,
Input to the motor 2 through the motor drive circuit 12 to control the motor 2. Further, the outputs of the frequency converter 6 and the frequency converter 7 are combined by the combining circuit 13 and sent to the monitor 15 through the demodulation circuit 14.

Next, an amplitude monopulse, which is another satellite tracking method, will be described with reference to FIG. The antenna 23 and the antenna 24 are arranged on the turntable 21 with their beam directions shifted. The output of the antenna 23 is converted into an intermediate frequency (IF) signal by the frequency converter 26, and converted into a DC signal according to the reception level by the level detector 28. Similarly, the output of the antenna 24 is the frequency converter 27.
And the level detector 29 converts the signal into a DC signal. Two
Since the beam directions of the antennas 23 and 24 are deviated, the two level detectors 28 and 29 generate different outputs as shown in FIG. 9 depending on the deviation from the satellite direction. An output as shown in FIG. 10 is obtained by passing these two outputs through the subtractor 30 and the amplifier 31. The output is controlled by the motor drive circuit 32 with the sign as the rotation direction of the motor 23 and the absolute value as the rotation speed. To do.

The outputs of the frequency converter 26 and the frequency converter 27 are combined by the combining circuit 33 and sent to the monitor 35 through the demodulation circuit 34. Further, as another method for tracking a satellite by one antenna, there is a step track method, which will be described with reference to FIG.

The output of the antenna 43 passes through a frequency converter 44 and is then converted by a level detector 45 into a DC value according to the reception level. The turntable 41 is moved in a certain direction to slightly change the orientation of the antenna. At this time, the reception level becomes higher as the position approaches the direction of the satellite, and conversely the reception level becomes lower as the position moves away from the satellite. This change in the reception level is detected by the level change detection circuit 46 and sent to the motor drive circuit 47. If the reception level increases, the motor 42
Move the antenna further in the same direction without switching the rotation direction. Conversely, when the reception level decreases, the rotation direction of the motor 42 is switched and the antenna is moved in the opposite direction.

[0009]

In each of the conventional methods, the phase monopulse and the amplitude monopulse have a drawback that the apparatus becomes complicated because a plurality of antennas and frequency converters are required and a synthesizing circuit is required. there were. The step track method uses a single antenna and a frequency converter, but since the turntable including the antenna has a large inertia, it cannot be used for a moving body that has poor responsiveness and changes its posture significantly. could not.

An object of the present invention is to propose a configuration of a simple and inexpensive device for effectively performing satellite tracking of a mobile antenna, which is an improvement over the above-mentioned drawbacks of the conventional system.

[0011]

In order to achieve the above object, the first invention of the present application comprises frequency conversion means for converting a reception signal from an antenna provided in a moving body into a predetermined frequency signal, In the satellite tracking receiver of the mobile antenna for detecting the deviation of the antenna with respect to the satellite direction based on the frequency signal and drivingly controlling the direction and rotation speed of the antenna so as to track the satellite according to the detection result, Level detection means for detecting a level change and outputting a level change detection signal, angular velocity detection means for detecting an angular velocity of the moving body to detect a satellite direction and outputting an angular velocity detection signal, and a signal based on the level change detection signal And the angular velocity detection signal are added and calculated, and the rotation speed of the antenna is changed according to the addition result and the direction is switched to track the satellite. And arithmetic processing means that is characterized by having a.

According to a second invention of the present application, in the device of the first invention, a level change detection signal from the level detecting means is input, and a predetermined first signal corresponding to the level change of the signal is input.
A first control signal output means for outputting a control signal; and a second control signal output means for inputting the level change detection signal and outputting a predetermined second control signal according to the level of the signal, The first control signal and the second control signal are output to the arithmetic processing means as signals based on the level change detection signal and added, and the angular velocity detecting means is set so that the addition result is substantially the same as the true angular velocity. It is characterized by calibrating the detection deviation in.

According to a third invention of the present application, in the apparatus of the first invention, it is detected based on an angular velocity detection signal from the angular velocity detection means that the angular velocity of the moving body is substantially zero, and a zero angular velocity signal is detected. Input angular velocity zero detection means, the level change detection signal from the level detection means and the angular velocity zero signal, and based on the both signals, the elevation angle and the azimuth angle of the antenna direction at predetermined time intervals. And a time-division control unit that causes the satellite to be tracked by a time-division control signal that alternately performs time-division control.

A fourth invention of the present application is, in the device of the first invention, demodulating means for demodulating the frequency signal from the frequency converting means and outputting a video signal including a detection signal and luminance information, and the detection signal. A noise detection / determination unit that detects a noise component included in a signal, and determines the presence or absence of an impulse noise component having a large single-shot luminance change included in the video signal based on the noise component amount and outputs a noise determination signal, When there is the impulse noise component by the noise determination signal, the impulse noise component is detected by detecting the impulse portion in the video signal, the luminance of the portion is interpolated, and the video signal from which the impulse noise component is removed is output. Noise detection / removal means for outputting the video signal from the demodulation means when there is no signal.

A fifth invention of the present application is, in the apparatus of the fourth invention, a frame difference component for extracting a frame difference component signal from a video signal containing the luminance information and a signal obtained by delaying the signal for a predetermined frame period. A motion for comparing the levels of the frame difference component signal and a predetermined reference signal with the extraction means and detecting the presence / absence of motion in upper and lower adjacent pixels in the same field based on the comparison result and outputting a motion detection signal. The detection means and the motion detection signal determine that the impulse noise component does not exist only when there is motion detection, and the impulse noise determination in which the output of the noise detection / removal means is only the video signal from the demodulation means Means and are provided.

According to a sixth invention of the present application, in the device of the fourth or fifth invention, when the noise detecting / removing means detects an impulse portion, the detection time is based on a control signal having a predetermined cycle. Residual impulse noise that is determined to be residual impulse noise when the time is longer than a predetermined time, the detection time is extended based on the cycle so as to remove the residual impulse noise, and an impulse noise removal signal with the extended detection time is output. A removing means is included.

A seventh invention of the present application is the apparatus according to the first, fourth or sixth invention, wherein the video signal includes an impulse noise component in the synchronizing signal, and the video signal is charged and A charging / discharging means for obtaining a video output signal which is discharged and synchronously clamped based on a synchronizing signal, a clamp reference signal generating means for generating a reference signal for performing the clamping operation, and the charged video signal as an input. Depending on the difference between the low frequency component extraction means for smoothing the impulse noise component contained in the synchronization signal and outputting it as a low frequency component image signal, the synchronization signal level of the low frequency component image signal, and the clamp reference signal level. Control signal generating means for generating and outputting a predetermined control signal, and the charging / discharging so that the synchronization signal level becomes the reference signal level based on the control signal. And discharge control means for obtaining a charge control and a video output signal from which the noise component has been removed means, characterized by comprising a.

An eighth invention of the present application is, in the device of the first, fourth or sixth invention, a brightness component extracting means for obtaining a brightness component signal from the video signal containing an impulse noise component, and the above video. A sync component signal extracting means for extracting a sync component signal from the signal, and clamp control at a level such that the potential difference between the negative peak of the brightness component signal and the pedestal level becomes a predetermined value, and a brightness component signal of a constant pedestal level is obtained. The synchronous clamp means, the reference signal generated at the substantially same level as the pedestal level, and the clamp-controlled luminance component signal are switched based on the synchronous component signal, and the porch portion of the luminance component signal is removed. And a pedestal replacing means for replacing the impulse noise component existing in the pouch portion with the level of the reference signal. And butterflies.

[0019]

In the device of the first invention of the present application, the received signal from the antenna is converted into a predetermined frequency signal. The level change of the frequency signal and the angular velocity of the moving body are detected, and a level change detection signal and an angular velocity detection signal are obtained respectively. The signal based on the level change detection signal and the angular velocity detection signal are added, and the rotation speed of the antenna is changed and the direction is switched according to the addition result, and the satellite is tracked.

In the device of the second invention of the present application, the first
In the invention, further, the first and second control signals corresponding to the level change are obtained from the level change detection signal,
These signals and the angular velocity detection signal are added, and the angular velocity detection deviation is calibrated so that the addition result is substantially the same as the true angle.

In the device of the third invention of the present application, the first
In the invention, further, based on the angular velocity detection signal, the angular velocity of the moving body is detected to be substantially zero to obtain a zero angular velocity signal, and the antenna direction is detected based on the level change detection signal and the zero angular velocity detection signal. The satellite tracking is performed by alternately controlling the elevation angle and the azimuth angle of the.

In the device of the fourth invention of the present application, the first
In the invention, the frequency signal is further demodulated to obtain a video signal including a detection signal and luminance information. A noise component included in the detection signal is detected, and it is determined whether or not the video signal includes an impulse noise component based on the amount of the noise component. When the noise determination signal includes an impulse noise component, the noise is interpolated to remove the noise. The output video signal is output.

In the device of the fifth invention of the present application, the fourth
In the invention, the frame difference component signal extracted from the video signal including the luminance information and the signal obtained by delaying the signal for a predetermined frame period is compared in level with a predetermined reference signal, Presence or absence of motion in the vertically adjacent pixels is detected to obtain a motion detection signal. When there is a motion detection by this motion detection signal, it is considered that there is no impulse noise component.

According to the sixth invention of the present application, in the fourth or fifth invention, further, when the impulse portion is detected, if the detection time is a predetermined time or more, it is judged as residual impulse noise, The detection time is extended to remove the residual impulse noise component.

In the device of the seventh invention of the present application, in the first, fourth, or sixth invention, further, when the sync signal of the video signal includes an impulse noise component, the impulse noise component is smoothed. The synchronous clamp control is performed so that both levels become equal by the control signal according to the difference between the sync signal level of the low frequency component video signal and the clamp reference signal level.

In the device of the eighth invention of the present application, in the first, fourth, or sixth invention, the impulse noise component existing in the pouch portion of the luminance component signal is further removed,
Luminance information is faithfully reproduced on the TV monitor.

[0027]

Embodiments of the present invention shown in the drawings will be described below.

Description of Embodiments of the First Invention FIG. 1 shows an embodiment of a satellite tracking device for a mobile antenna according to the first invention of the present application. In the figure, 51 is a turntable on the moving body, 52 is a drive motor thereof, 53 is an antenna mounted on the turntable 51, and 55 is a frequency converter, which constitutes the frequency converting means. 55 is a level detector, and 56 is a level change detector, which constitute the level change detecting means. Reference numeral 57 is a switch for selecting + V or -V, and 58 is an angular velocity sensor, which constitutes the angular velocity detecting means. An adder 59 constitutes the arithmetic processing means. A motor drive circuit 60 drives and controls the direction and rotation speed of the antenna 53 in accordance with the output of the adder 59 so as to track the satellite. DM is a demodulation circuit, and MO is a monitor.

Next, the operation of the above embodiment will be described. The output of the antenna 53 passes through the frequency converter 54 and is then converted by the level detector 55 into a DC signal corresponding to the reception level. The level change detection circuit 56 detects the level change of the DC signal, and switches the switch 57 according to the detected level change. At this time, the switch 57 is switched only when the level change detection circuit 56 detects a decrease in the level, and is not switched when the level rises. The switch 57 switches the voltage between + V and -V according to the detection signal of the level change detection circuit 56. Adder 59
Then, the + V and −V voltages selected by the switch 57 and the output voltage ωg of the angular velocity sensor 58 are added. The relationship between the angular velocity of the angular velocity sensor 58 and the output voltage is shown in FIG. The sign of the angular velocity ω is the angular velocity generated during the right curve +
I am trying. The motor drive circuit 60 switches the rotation direction of the motor 52 according to the sign of the output of the adder 59, but rotates the motor 52 counterclockwise when the output of the adder 59 is +. Also, a signal is output so that the absolute value of the output of the adder 59 and the rotation speed of the motor 52 are proportional.

The actual control will be described by taking the right curve as shown in FIG. 3 as an example. Now, it is assumed that this device is rotating counterclockwise at a speed of ωg + V as shown in A of FIG. At this time, since the antenna 53 moves away from the direction of the satellite, the reception level drops, and the level change detection circuit 56 detects this and switches the switch 57 from + V to -V. As a result, the rotation speed of the motor 52 is reduced to ωg-V, so that the present apparatus goes from the state B toward the satellite to the state C and captures the satellite. During this period, the reception level increases, so the rotation speed of the motor 52 is fixed at ωg-V. When the state of D is passed after the state of C, the antenna 52
However, the reception level decreases because the deviation from the direction of the satellite. The level change detection circuit 56 detects this level change and switches the switch 57 from -V to + V. As a result, the rotation speed of the motor 52 increases to ωg + V, so that the state becomes like E and heads again toward the satellite.

In the system of the present invention, the angular velocity sensor 58 is used as a bias servo, and the direction of the satellite is first roughly grasped, and the control is performed accurately based on the reception level. As a result, the followability of the antenna 53 can be improved as compared with the above-mentioned conventional step track system, and a single satellite can be used as a mobile satellite tracking device as compared with the monopulse system.

FIG. 4 shows how the rotation speed of the motor 52 is switched when turning the right curve as shown in FIG. Where ω
g is the angular velocity output by the angular velocity sensor 58, and ωo is the true angular velocity of the moving body. As can be seen from FIG. 4, even if the angular velocity ωg output by the angular velocity sensor 58 does not match the true angular velocity ωo of the moving body, ωg−V <ωo <ωg
Control is valid in the range of + V. In other words, it is not necessary to use a highly accurate gyro or the like as the angular velocity sensor, and an inexpensive one may be used.

The frequency signal output from the frequency converter 54 is sent to the demodulation circuit, but since a single antenna is required,
No synthesis circuit is required during this period. As the level detector in the present embodiment, the applicant has applied for
For example, the one described in Japanese Patent Application No. 3-256979 can be applied.

Description of Embodiment of Second Invention Next, FIG. 12 shows an embodiment of a satellite tracking device for a mobile receiving antenna according to the second invention of the present application. In the figure, 61 is an antenna, 62 is a turntable on which the antenna is mounted, and 63 is a frequency converter. Reference numeral 64 is a level detector, and 65 is a level change detection circuit, which constitutes the level detection means. Reference numeral 66 denotes a switch for selecting and outputting the voltage of + V, -L in response to the level change detection signal from the level change detection circuit 65, and constitutes the first control signal output means. 67 is a triangular wave generating circuit, which constitutes the second control signal output means. 68 is an angular velocity sensor as the angular velocity detecting means, and 69 and 70 are adders, which constitute the arithmetic processing means. Reference numeral 71 is a motor drive circuit, 72 is a turntable (antenna) drive motor, 73 is a demodulation circuit, and 74 is a monitor.

Next, as the operation of the above-mentioned embodiment, first,
The case where the radio wave is not shielded will be described. The output of the antenna 61 passes through a frequency converter 63 and is then converted by a level detector 64 into a signal having a DC value DC corresponding to the reception level. In the level change detection circuit 65, this DC value DC
Then, the switch 66 is changed over. The switching of the switch 66 at this time is performed by the level change detection circuit 6
Each time 5 detects a decrease in level, it outputs a level change detection signal of H and L levels alternately to switch the switch 66, and does not switch when the level rises. The switch 66 selects + V when the signal of the level change detection circuit 65 is H, and selects -V when it is L.

The output of the level change detecting circuit 65 is also transmitted to the triangular wave generating circuit 67, and increases the output voltage α of the triangular wave generating circuit 67 when it is at the H level and decreases it when it is at the L level. The adder 69 adds the output voltage α of the triangular wave generation circuit 67 and the output ωg of the angular velocity sensor 68 and outputs the output voltage ωg + α.

In the adder 70, the + V or -V voltage selected by the switch 66 and the output voltage ωg + α of the adder 69.
Is added. The motor drive circuit 71 switches the rotation direction according to the sign of the output of the adder 70, but the motor 72 rotates counterclockwise when the output of the adder 70 is +. In addition, a signal is output so that the absolute value of the output of the adder 70 and the rotation speed of the motor 72 are proportional to each other.

The actual control will be described by taking a right curve as shown in FIG. 13 as an example. True angular velocity of moving body ω
o, the output of the angular velocity sensor 68 is ωg, and it is assumed that the two are displaced in the state of ωo> ωg.

It is assumed that the level change detection circuit 65 outputs an H level signal and the device is rotating counterclockwise at a speed of (ωg + α) + V. The output of the level change detection circuit 65 is H
Because of the level, the output α of the triangular wave generation circuit 67 increases,
The output ωg + α of the adder 69 is also the output of the adder 70 (ωg +
α) + V also increases as shown in FIG. When the antenna 61 is in a state A away from the direction of the satellite, the level change detection circuit 65 detects a decrease in the reception level, the output becomes L level, and the switch 66 is switched from + V to -V. As a result, the rotation speed of the motor 72 is reduced to (ωg + α) -V, so that the device turns toward the satellite and reaches the state B where the decrease in the reception level is detected again. During this period, since the output of the level change detection circuit 65 is L, the output α of the triangular wave generation circuit 67 decreases and the output ωg + α of the adder 69 also increases.
The output (ωg + α) -V of 0 also decreases as shown in FIG.
When a decrease in the reception level is detected in the state of B, the output of the level change detection circuit 65 becomes H level and the state returns to the initial state. In this way the device shuttles back and forth between A and B about the satellite direction.

During the beginning of this reciprocating motion, ωg + α <ωo
Therefore, the time required between B and A is longer than the time required between A and B. As a result, ωg + α gradually increases while repeatedly increasing and decreasing, and eventually settles near ωo. Thus, the true angular velocity ωo and the output ωg of the angular velocity sensor
Even if there is a deviation, calibration is performed by the triangular wave generation circuit 67, and the output ωg + α of the adder 69, which is the output after calibration, becomes substantially equal to the true angular velocity.

When the radio wave is shielded, the output of the level change detection circuit 65 is forcibly pulsed with a duty of 50%, so that the output of the adder 69 can be maintained in a state in which the calibration before the shield is effective. ..

The triangular wave generating circuit 67 is, for example, as shown in FIG.
It can be realized by a circuit like 5. In FIG. 15, the signal from the level change detection circuit 65 is changed to UP / DOWN of the counter 74.
When the output of the level change detection circuit 65 is at H level, the counter 74 is connected to the terminal and the clock CLK is input.
Count value increases, and decreases at the L level. This signal may be converted into an analog voltage by the D / A converter 75.

Description of Embodiment of Third Invention Further, FIG. 16 shows an embodiment of a satellite tracking receiver for a mobile antenna according to the third invention of the present application. In the figure, reference numeral 81 is an antenna, and 82 is a frequency converter, which constitutes the frequency conversion means. Reference numeral 83 is a demodulation circuit, and 84 is a monitor. Reference numeral 85 is a level detector, and 86 is a level change detection circuit, which constitutes the level change detection means. 87 is a speed setting unit, 88 is a drive motor switching unit, and the speed setting unit 87
Is provided with the angular velocity detecting means, and the drive motor switching section 88 includes the angular velocity zero detecting means and the time division control means. Reference numeral 89 is an azimuth control motor, and 90 is an elevation control motor.

In FIG. 16, the signal received by the antenna 81 is converted into a low frequency IF signal by the frequency converter 82, and then transmitted to the monitor 84 via the demodulation circuit 83. Upon receiving the frequency signal output from the frequency conversion circuit 82, the level detector 85 outputs a signal Vl having a DC value corresponding to the reception level. At this time, the level detector 85
The output signal Vl of the signal becomes higher as the reception level becomes higher. A change in the reception level is detected by the level change detection circuit 86, and the antenna 81 is rotated through the motors 89 and 90 so that the reception level increases. Motor 89 at this time,
The speed setting unit 87 sets the rotation direction and speed of 90.
Is. Further, the present system is characterized in that both the azimuth angle and the elevation angle are controlled by one antenna 81, but not both are controlled at the same time, but the time division control is performed. Therefore, it is necessary to determine which direction to control, and the drive motor switching unit 88 makes this determination.

Next, each part will be described. First, a concrete example of the level change detection circuit 86 will be described with reference to FIG. In the figure, 86-1 is an adder, 86-2
And 88-5 are low-pass filters (LPF), 86-
3, 86-6 and 86-7 are comparators, and 86-4 is a subtractor.

In FIG. 17, the reception level signal Vl from the level detector 85 is added to the variable resistor R ₁ by the adder GD86-1.
The voltage Vgd from is added and Vl + Vgd is output.
Vfg can be obtained by passing this signal through the LPF 86-2 having an appropriate time constant. As can be seen from FIG. 18, Vl has a higher responsiveness than Vfg, so if Vl rises at a certain rate of rise, Vl> Vfg, and comparator GD8
6-3 The output SGD becomes H level, and the rise of the reception level can be detected. Similarly, the reception level signal Vl from the level detector 85 is subtracted by the voltage Vbd from the variable resistor R ₂ by the subtractor 86-4, and Vl-Vbd is output. Vfb is obtained by passing this signal through the LPF 86-5. As in the case of Vfg, Vl has higher responsiveness than Vfb, so if Vl falls at a certain rate of decline, Vl <V
It becomes fb, the comparator BD86-6 output SBD becomes H level, and the drop of the reception level can be detected. Furthermore, when comparing the voltage Vng from Vl and variable resistor R ₃ in comparator NG86-7, comparator NG if the reception level is Vng more
Since the 86-7 output SNG becomes H level, it can be determined that the satellite is being captured.

Next, the operation of the speed setting unit 87 will be described with reference to FIG.
Will be explained. In FIG. 19, 87-1 is a speed switching circuit, 87-2 is an angle sensor correction circuit, 87-3,
87-6 is an adder, 87-4 is an angle sensor, 87-5
Is a switch. As shown in FIG. 20, the speed switching circuit 87
The output SWS of -1 has a cycle T when the SNG = L level.
Although the pulse has a duty of 50%,
When G = H level and SGD = H level, the above SGD
The value at that time is extended by the time ΔT at the H level. Further, when the SBD changes to the H level at the SNG = H level, the SWS is inverted at the rising edge thereof.

This SWS is an angular velocity sensor correction circuit 87.
-2, the output voltage Vc is increased at the H level and decreased at the L level. This angular velocity sensor correction circuit 87-2 can be realized using, for example, a counter 87-2-1 and a D / A converter 87-2-2 as shown in FIG. When the output AOE of the drive motor switching unit 88, which will be described later, is connected to the ENABLE terminal E of the counter 87-2-1, the AOE becomes L level and the counting operation is stopped during the elevation angle control. During the azimuth control, AOE becomes H level, so the following counting operation is performed.

When the output SWS of the speed switching circuit 87-1 is connected to the UP / DOWN terminal U / D of the counter 87-2-1 and a clock is input, the count value increases when the output of SWS is H level. , L level decreases. This signal may be converted into the analog voltage Vc by the D / A converter 87-2-2.

The adder 87-3 adds this Vc and the output Vωg of the angular velocity sensor 87-4 and outputs Vc + Vωg. This signal is referred to as CLG, and this CLG is transmitted to the drive motor switching unit 88 for switching the drive motor. Since the SWS can be used for switching the rotation direction of the elevation angle control motor 90, it is transmitted to the drive motor switching unit 88. SWS is also used as a switching signal for the switch 87-5. The switch 87-5 has a voltage + Va when SWS = H level and a negative voltage −Va when SWS = L level.
Select. This ± Va and CLG are added by the adder 87-6 to obtain a signal MSA of (Vωg + Vc) ± Va.
This MSA is transmitted to the drive motor switching section 88 as a speed signal of the azimuth control motor 89.

The operation of the circuit when the elevation angle is actually controlled will be described with reference to FIG. Assuming that the satellite radio waves are being captured, the SNG signal from the level change detection circuit 86 is at H level. The graph of FIG. 16 shows the directivity of the antenna in the elevation angle direction when the satellite direction is 0. If the directivity direction of the antenna 81 is changing from point a to point b, the satellite direction is The reception level Vl decreases as it moves away from, and the level change detection circuit 86 detects this and the SBD changes from the L level to the H level. At this rising, the SWS from the speed switching circuit 87-1 is reversed, so that the rotation direction of the elevation angle control motor 90 is also reversed, and the antenna 81 moves toward the satellite. As a result, the reception level Vl rises and the SGD from the level change detection circuit 86 becomes H level. When the antenna 81 moves to point c in FIG. 16, the increase in reception level stops and SGD becomes L level. By the operation of the drive motor switching unit 88 described later, the elevation angle control motor 90 stops at this position, the elevation angle control is completed, and the azimuth angle control is performed. As will be described with reference to the drive motor switching unit 88, when the radio wave of the satellite is not captured, that is, S
The elevation angle is not controlled when NG = L level.

Next, the actual control of the azimuth angle will be described by taking the right curve as shown in FIG. 23 as an example. First, a case where the radio wave is not shielded will be described. The voltage conversion value of the true angular velocity of the moving body is Vωo, and the angular velocity sensor 87-
The output of 4 is Vωg, and these two are now Vωo> Vω
It is assumed that there is a shift of g.

It is assumed that the SWS from the speed switching circuit 87-1 is at H level and the device is rotating counterclockwise at a speed of (Vωg + Vc) + Va. Since SWS = H level, the output Vc of the angular velocity sensor correction circuit 87-2 increases, and the output Vωg + Vc of the adder 87-3 and the output (Vωg + Vc) + Va of the adder 87-6 also increase as shown in FIG. When the antenna 81 moves to the state of A away from the direction of the satellite, the level change detection circuit 86 detects the decrease of the reception level Vl, the SBD rises, the SWS is inverted to the L level, and the switch 87-5 is turned to + Va. From-Va
Switch to. As a result, the rotation speed of the motor 81 becomes (V
Since it decreases to ωg + Vc) −Va, the device heads toward the satellite, but at this time the reception level increases and SGD = H level. Even if the satellite is captured and SGD = L level, the state of SWS = L level continues for a while, and the antenna 81 moves away from the satellite. During this time, the output Vc of the angular velocity sensor correction circuit 87-2 decreases, and the output Vωg + Vc of the adder 87-3 and the output (Vωg + Vc) −Va of the adder 87-6 also decrease as shown in FIG.
When the decrease in the reception level is detected in the state of B and SBD rises, the SWS of the speed switching circuit 87-1 becomes H level and returns to the initial state. In this way the device shuttles back and forth between A and B about the satellite direction.

During the first part of this reciprocating motion, Vωg> Vωg
Since it is + Vc, the time required for B → A is A →
It is longer than the time required between B. As a result, Vωg + Vc gradually increases while repeatedly increasing and decreasing, and eventually settles near Vωo. Thus, the voltage conversion value Vωg of the true angular velocity
Then, even if the output Vωg of the angular velocity sensor 87-4 is deviated, the correction is performed by the angular velocity sensor correction circuit 87-2,
The output of the adder 87-3, which is the corrected output, is Vωg + Vc.
Becomes almost equal to the voltage conversion value Vωo of the true angular velocity.

When the electric wave is cut off, SNG becomes L level, and the SWS of the speed switching circuit 87-1 has a duty of 5
Since the pulse is 0%, the output of the adder 87-3 can be maintained in the correction state before being shielded.

Next, there is a drive motor switching unit 88. This is to generate a signal for switching the motor to be driven in order to control the elevation angle only when the satellite is in the capture state and the moving body is stopped or going straight. Has a purpose. In addition, when an angular velocity is generated during elevation angle control, or when electromagnetic waves are shielded, the elevation angle is returned to its original position, and then control is performed for azimuth angle.

FIG. 25 shows an example of the configuration of the drive motor switching section 88. 88-1 and 88-8 are comparators, 88-2 is a set circuit, 88-3 is a reset circuit, 88-4 is a zero detection circuit, 88-5 is a motor switching circuit, 88-6 is a position detection circuit, 88-7 is a position hold circuit, 88-9 is an azimuth motor drive circuit, 88-10 is an elevation motor drive circuit,
R _3, R ₄ is positive, negative voltage + V _2, a variable resistor for generating -V _2.

The operation of the drive motor switching unit 88 having the above-described structure will be described with reference to FIG. In order to determine whether the moving body is stopped or traveling straight, the speed setting unit 87 inputs a signal CLG of Vωg + Vc to the comparator 88-1. If the condition of −Vz <Vωg + Vc <Vz is satisfied, it is determined that the vehicle is stopped or traveling straight, and the output COM is set to the H level.

The set circuit 88-2 is a zero detection circuit 88-4.
From MSW = L level, COM = H level, and SNG = H level from the level change detection circuit 86, S
When GD falls, the output SET is set to L level for a certain period of time (Fig. 20-a1, a2, a3).

When SGD falls at MSW = H level, COM = H level and SNG = H level, the reset circuit 88-3 first sets VAL1 to H level and then RESET to L level for a certain period of time. When RESET returns to H level, VAL1 goes to L level (Fig. 20-
b1). When COM = L level or SNG = L level, RESET = L level and VAL1 = L level are output (FIGS. 20-b2 and b3).

The zero detection circuit 88-4 sets MSW = H level and VAL2 = L level at the falling edge of SET (FIG. 20-a1, a2, a3). If VAL1 = H level at the falling edge of RESET, VAL2 = H level is set, and then MSW = L level (FIG. 20-b1). R
If VAL1 = L level at the falling edge of ESET, VA
MS2 is set to L level while L2 is set to L level (FIG. 20).
-B2, b3).

In the motor switching circuit 88-5, since MSW falls, AOE = L level and bar AOE = H level. At this time, the MSW is the position hold circuit 88-7.
And the value of the position PEL of the elevation angle control motor 90 detected by the position detection circuit 88-6 is transmitted to the position hold circuit 8 as well.
Hold at 8-7 (Fig. 20-a1, a2, a3).
The motor switching circuit 88-5 is VAL at the fall of MSW.
If 2 = H level, AOE = H level, bar AOE =
Set to L level (FIG. 20-b1). If VAL2 = L level at the fall of MSW, VAL3 = H level is set (FIGS. 20-b2 and b3). While VAL3 = H level, the elevation angle motor drive circuit 88-10 ignores the SWS from the speed setting block 87, and the COM of the comparator 88-8 is detected.
In accordance with B, the elevation angle control motor 90 is moved to the position hold circuit 88.
-7 is controlled to return to the held position. When the elevation angle control motor 90 returns to the position of HPEL, the magnitude relationship between PEL and HPEL is reversed, and COMB is also reversed. Upon detecting this inversion, the motor switching circuit 88-5 causes VAL3 = L level, AOE = H level, and bar AOE =.
It is set to L level (FIGS. 20-c2 and c3).

The azimuth motor drive circuit 88-9 has AOE =
At the H level, the azimuth control motor 89 is driven to
Stop when E = L level. The speed and the rotation direction are given by the MAS from the speed setting unit 87, and the absolute value of the MSA determines the speed and the sign determines the rotation direction.

The elevation motor drive circuit 88-10 is a bar AO.
The elevation angle control motor 90 is driven when E = H level, and stopped when the bar AOE = L level. In this embodiment, the speed is constant, but it can be variable.
The rotation direction follows SWS from the speed setting block when VAL3 = L level, but follows COMB when VAL3 = H level.

Finally, the operation of the drive motor switching section 88 will be described by taking an actual traveling state as an example. Now, assume that the mobile body is curving while receiving radio waves. Since it is receiving, SNG = H level, because it is curved, COM = L level, and COM = L level, MSW = L level. When the vehicle goes straight from this state, the comparator 88-1 detects this and becomes COM = H level. The reception level changes due to the control of the azimuth angle, but when the increase in the reception level stops, SGD = L level. Since this corresponds to FIG. 26-a1, AOE and bar AOE are reversed, and control of the motor shifts from azimuth to elevation. If the vehicle continues to go straight without being shielded from radio waves, SNG remains at H level and COM remains at H level. When the elevation angle is controlled until the increase in the reception level stops, SNG falls, but the logic of the angle signal at this time corresponds to that in FIG. 26-b1, so AOE and bar AOE are inverted, and azimuth control is performed again. Move on to.

When the control of the azimuth angle is completed (FIG. 26-a)
2) The control shifts to the elevation angle, but this time, it is assumed that the moving body curves during the elevation angle control. When (Fig. 26-a2), MS
At the rising edge of W, the position of the elevation angle control motor 90 is held by the position hold circuit 88-7. -V depending on the curve
The relationship of z <Vωg + Vc <+ Vz is not established and CO
M = L level. (FIG. 26-b2) Since COM = L level, the reset circuit 88-3 has VAL = L level, R
Outputs ESET = L level. As a result, the zero detection circuit 88-4 causes MSW to fall while keeping VAL2 = L level. The motor switching circuit 88-5 outputs VAL3 = H level, while the elevation motor drive circuit 88-10 controls the elevation control motor 90 according to the COMB from the comparator 88-8. When the motor returns to its original position, COM
Since B is inverted, VAL3 = L level, AOE = H
Level, bar AOE = L level, and control shifts from elevation to azimuth.

When the electric wave is shielded during the elevation angle control, S
Although NG = L level (FIG. 26-b3), the subsequent operation in this case is similar to the above example. By repeating such an operation, the azimuth angle and the elevation angle can be controlled in a time division manner. In addition, 88- in the drive motor switching unit 88
1 to 88-8 can be replaced with a microcomputer.

Fourth Embodiment of the Invention Further, in each of the above embodiments, each demodulation circuit has any one of the following devices for removing impulse noise contained in the demodulation signal system and interpolating the removed portion. Is preferably used.

FIG. 27 is an embodiment according to the fourth invention of the present application, in which the C / N of the received signal is lowered and the impulse noise called medaka noise is generated, the impulse noise is detected and removed from the video signal. Accurately and reliably,
The present invention relates to a noise eliminator that accurately compensates for damaged image quality. In the figure, 91 is an antenna, 92 is an intermediate frequency conversion circuit (LNB), 93 is a first IF signal, 94 is a tuner, 95 is a video signal, 96 is a noise reduction circuit which is a means for detecting and removing medaka noise, and 97 is Detected signal, 98 is a noise detection circuit which is a medaka noise detection / determination means, 99 is a noise reduction control signal, 10
0 is a noise reduction video signal, 101 is an audio signal,
102 indicates a monitor.

In such a configuration, the received signal received by the antenna 91 is sent to the LNB 92 as the first signal.
The IF signal 93 is frequency-converted and sent to the tuner 94. The tuner 94 selects a desired channel and performs FM demodulation. The tuner 94 outputs a video signal 95, a detection signal 97, and an audio signal 101. Detection signal 97
Is a signal immediately after FM demodulation. After de-emphasis of the detection signal 97, the 15 Hz triangular wave is removed, and the LPF in the video signal band is passed to obtain a video signal 95. The noise reduction circuit 96 detects and removes medaka noise, the detailed configuration of which will be described later.

When the medaka noise is detected in the noise reduction circuit 96, a portion which is not medaka noise may be erroneously detected as medaka noise (erroneous detection), and a noise removing operation is performed on this erroneously detected portion. If you do, the image quality of that part will be impaired. Therefore, the occurrence probability of false detection must be made sufficiently smaller than the occurrence probability of medaka noise. Further, when C / N (for example, about 6 dB or less) in which no medaka noise is generated is obtained, it is necessary to prohibit noise removal in the noise reduction circuit 96.

Therefore, a noise detection circuit 98 is provided,
C / N is detected. The noise detection circuit 98 detects only the noise component included in the detection signal 97 and obtains a voltage according to the noise level (for example, about 1 to 2 V). From the voltage, C / N
Or not, and outputs the determination result to the noise reduction circuit 96 as a noise reduction control signal 99.

When the control signal 99 indicates C / N in which medaka noise occurs, the noise reduction circuit 96 detects the medaka noise portion in the video signal and interpolates the luminance of the portion. And supplies it as a noise reduction video signal 100 to the monitor 102. Further, the control signal 99 is a C / N in which medaka noise does not occur.
If it indicates, the video signal 95 from the tuner 94 is supplied to the monitor 102 without being interpolated.
On the other hand, the audio signal from the tuner 94 is supplied to the monitor 102 as in the conventional case.

FIG. 28 shows a schematic structure of the noise reduction circuit. In the figure, FM from the tuner 94
The demodulated video signal 95 is converted into 4 by the A / D converter 103.
A / D conversion is performed at a sampling frequency of fsc (about 14.318 MHz), and a YC separation circuit 104 separates the luminance signal (Y signal) and the chroma signal (C signal). The Y signal is applied to the impulse noise detection circuit 96-1 to generate the Y signal.
Detects impulse noise (medaka noise) from the signal,
Noise interpolation circuits 96-2 and 96- are provided according to the detection result.
With respect to the Y signal and the C signal by 3, the pixel in which the noise is detected is interpolated by the adjacent pixel that does not include noise. The interpolated Y and C signals are mixed by the YC mix circuit 129, D / A converted by the D / A conversion circuit 130, and output.

FIG. 29 is a block diagram showing a concrete example of the configuration of the noise reduction circuit 96. Reference numeral 103 is an A / D converter, 104 is a YC separation circuit, 105 is a luminance signal, and 106 is a luminance signal.
-1 to 106-4 are line memories, 107 is a 1H delayed luminance signal, 108 is a 2H delayed luminance signal, 109 is a frame memory, 110 is a frame delayed luminance signal, 111 to 11
3 is a difference signal, 114-1 to 114-3 are absolute value circuits, 1
15-1 to 115-3 are comparison circuits, 116 is a threshold,
Reference numeral 117 is a 3-input AND circuit, 118 is a medaka noise detection signal, 119 is an interpolation luminance signal, 120 and 121 are switches, 122 is a chroma signal, 123 is a 1H delay chroma signal, 124 is a 2H delay chroma signal, and 125 is a phase inversion circuit. 126 is an interpolated chroma signal, 127 and 128 are switches, 129 is a YC mix circuit, 130 is a DA converter,
131-1 to 131-3 are subtractors, 132-1 to 132
-2 indicates an adder, and 133-1 to 133-2 indicate 1/2 multipliers.

In FIG. 29, the video signal 95 from the tuner 94 is passed through the A / D converter 103, and then separated into the luminance signal 105 and the chroma signal 122 by the YC separation circuit 104, and the line memories 106-1 are respectively provided. To 106-4.

Then, the line memories 106-1 and 1
06-2 to 1H and 2H delayed luminance signals 10 respectively
7 and 108 are obtained. On the other hand, the line memory 106-3
~ 106-4 from 1H and 2H chroma signal 1 respectively
23 and 124 are obtained. Also, the 1H delayed luminance signal 10
7 is passed through the frame memory 109 to obtain the frame delay luminance signal 110.

FIG. 30 shows the 1H delayed luminance signal 107 as a center on the vertical space-time axis. Figure 30
N (0) of 1H delayed luminance signal 1 at a certain time t
07, n (A) and n (B) are 2H, respectively.
Shows the delayed luminance signal 108 and the luminance signal 105, n
(C) shows the frame delay luminance signal 110. Note that (0) such as n (0) represents the subscript of n.

Since the television image signal is statistically highly correlated between the upper and lower lines and between the frames, n
In (0), medaka noise can be determined when none of n (A), n (B), and n (C) has a certain correlation. However, in the case of this embodiment, erroneous detection may occur in the frequency region shown by the hatched portion in FIG. 24, but it was tested that the image quality deterioration due to this erroneous detection is sufficiently smaller than the effect of removing medaka noise. Have been confirmed.

The above medaka noise detection operation will be described with reference to FIG. From the 1H delayed luminance signal n (0) 107,
2H delayed luminance signal n (A) 108, luminance signal n (B) 1
05 and the frame delay luminance signal n (C) 110 are subtracted by subtractors 131-1 to 131-3, respectively, and their difference signals, that is, n (0) -n (A) signals 111, n.
The (0) -n (B) signal 112 and the n (0) -n (C) signal 113 are calculated, and the difference signal between them is calculated by the absolute value circuit 114-.
1 to 114-3 to obtain an absolute value, the comparison circuits 115-1 to 115-3 determine the magnitude of the threshold value 116, and the result is input to the 3-input AND circuit 117 to obtain the value. The one is the medaka noise detection signal 118.
Here, the threshold value 116 is set to an optimum value through experiments.

When medaka noise is detected, an operation for replacing the detected portion with some signal, that is, interpolation is required. Therefore, in the embodiment of FIG. 29, the luminance signal 105 and the 2H delayed luminance signal 108 are added to the adder 132-
The signal is passed through the 1/1/2 multiplier 133-1 and interpolation is performed using the average value of these signals.
Is input to the switch 120.

In the switch 120, the 1H delayed luminance signal 1
07 and the interpolated luminance signal 119 are selected by the medaka noise detection signal 118 output from the AND circuit 117 and output. The switch 121 controls by the noise reduction control signal 99 so as to select the 1H delayed luminance signal 107 in the C / N where medaka noise does not occur and to select the output of the switch 120 in the C / N where medaka noise occurs. To do.

Also for the chroma signal 122, when medaka noise is detected, it is necessary to interpolate. Therefore, the chroma signal 122 and the 2H delayed chroma signal 124 are passed through the adder 132-2 and the 1/2 multiplier 133-2,
The average value of those signals is calculated, and the average value is calculated.
The phase is inverted by 25 to obtain the interpolated chroma signal 126, the signal 126 and the 1H delayed chroma signal 123 are input to the switches 127 and 128, and the switch 127 operating in synchronization with the switch 120 outputs the medaka noise detection signal 118. Select and output. The switch 128 is synchronized with the switch 121, and its operation is exactly the same.

The phase of the interpolated chroma signal 126 is inverted by the phase inversion circuit 125. In the NTSC system, since the phase of the chroma signal is inverted line by line, the interpolated chroma signal 126 is delayed by 1H. Chroma signal 123
This is to make it in phase with. Switches 121 and 12
After the output of 8 is combined by the YC mix circuit 129, D
The signal is converted into an analog signal by the / A converter 130 and output as the noise reduction video signal 100.

In the above-described embodiment of the present invention, theoretically no false detection occurs in a still image. Further, since the luminance signal and the chroma signal are respectively interpolated after YC separation, it is possible to interpolate between upper and lower pixels. That is, since the interpolation can be performed using the closest pixel, the deteriorated image quality can be accurately compensated.

Description of Embodiments of Fifth Invention Next, a fifth invention of the present application is to remove impulse noise contained in a video signal of a moving image as well as a still image like the above-mentioned fourth invention. It is suitable for interpolation, and the motion detection method described below is adopted.

FIG. 32 shows the above-mentioned motion detecting method.
Pixels S10 and S1 above and below the target pixel S11
Consider the three pixels that combine 2 as one block, and
When a motion is detected in either 0 or S12, it is determined that the pixel S11 has a motion. Motion detection of the pixels S10 and S12 is performed by detecting the pixel S20,
The level is compared with S22, and the level difference and the threshold value are compared. That is, assuming that the threshold for motion detection is R2, it is determined that there is motion in S11 when the condition of | S10-S20 |> R2 or | S12-S22 |> R2 is satisfied, and from the candidates of impulse noise, exclude.

FIG. 33 shows a principle circuit configuration for carrying out the above-described motion detecting method of the present invention. In the figure, 200 is the pixel S12, 201 is S11, 202.
Is S10, 203-1 to 203-4 are line memories, 2
04 is a frame memory, 205 is S22, and 206 is S2
1, 207 is S20, 208 is a motion detection signal of 1H before,
209 is a motion detection signal after 1H, 210 is a motion detection signal, 211 is an OR circuit, and 212-1 and 212-2 are frame correlation determination circuits. S12 (200) is added to the line memory 203-1 and the frame memory 204,
S11 (201) is obtained from the line memory 203-1 and S10 is output via the line memory 203-2. S22 is output from the frame memory 204, S21 (206) is obtained from the line memory 203-3, and S20 is further output via the line memory 203-4.

The frame correlation determination circuit 212-1 is | S1.
0-S20 |> R2 is judged and 1H of S11 (201)
Motion detection is performed for the previous S10 (202) and 1H
The front motion detection signal 208 is output. Further, the frame correlation determination circuit 212-2 determines | S12-S22 |> R2, detects the motion of S12 (200) after 1H of S11 (201), and outputs a motion detection signal 209 after 1H. The signals 208 and 209 are ORed by an OR circuit 211 to obtain a motion detection signal 210.

FIG. 34 shows a fifth example of the present application based on the above-described principle.
29, the part indicated by the broken line is the impulse noise detecting part similar to that of FIG. 29, and the part indicated by the alternate long and short dash line is the motion detecting part added by the present invention.

FIG. 35 shows another embodiment of the present invention, which is different from FIG. 34 in that the structure of the impulse noise detector indicated by the broken line is partially changed in order to save the frame memory.

In FIG. 34, the motion detecting section includes a frame memory 301, an adder 315, an absolute value circuit 304,
Comparing circuit 306, line memories 309-1, 309-
2, NOR circuit 311, AND circuit 313,
2 is a frame delay luminance signal, 305 is a frame difference signal,
Reference numeral 307 is a threshold value signal for motion detection, 308 is a backward motion detection signal for 1H, 310 is a forward motion detection signal for 1H, and 312 is a motion detection signal.

In the motion detecting section, the frame memory 301, the adder 315 and the absolute value detecting circuit 304 constitute the frame difference component extracting means. Furthermore, the comparison circuit 3
06, the line memories 309-1 and 309-2 and the NOR circuit 311 constitute the motion detecting means, and the AND circuit 313 constitutes the impulse noise determining means. Then, the impulse noise detecting section is provided with a line memory 31.
6-1, 316-2, 316-3, adder 317-1,
317-2, comparison circuits 318-1, 318-2, 318
-3, absolute value circuits 119-1 and 119-2, and an AND circuit 321 to constitute the noise detection determination means, and the noise detection and removal means has the same configuration as the noise interpolation units Y and C in FIG. Was omitted.

In the embodiment of FIG. 26, the same reference numerals as those in FIG. 25 denote the same or similar circuits, and the motion detecting unit has the same configuration, but the impulse noise detecting unit is the frame memory 3
22, an addition circuit 323, an absolute value circuit 324, and a comparison circuit 325 are further provided, and the configuration is almost the same as that of FIG. The impulse noise detection unit in FIG. 25 shares a frame memory and the like with the motion detection unit, and has substantially the same function as in FIG.

Next, the operation of the motion detector of the embodiment shown in FIG. 25 will be described. The luminance signal Y from the Y / C separation circuit 104 is input to the frame memory 301 and the adder 115, and the difference from the frame delay luminance signal 302 delayed by one frame period is calculated by this frame memory, and the absolute value circuit 304. The frame difference signal 305 is extracted via.

This frame difference signal 305 is sent to the comparison circuit 30.
6, the level is compared with the motion detection threshold value signal 307, the 1H backward motion detection signal 308 is obtained according to the magnitude, and the 1H forward motion signal 310 is obtained via the line memories 309-1 and 309-2. Noa Cairo 31 for both signals
1 and the motion detection signal 312 is output. This motion detection signal 312 becomes L level when motion is detected, and becomes H level when motion is not detected. Further, since the impulse noise candidate signal (the medaka noise detection signal) becomes H level when it is determined that the candidate is impulse noise, it is output from the AND circuit 313 to which the motion detection signal 312 and the impulse noise detection signal 320 are input. The impulse noise detection signal 314 is excluded from candidates for impulse noise when motion is detected,
It is considered that there is no impulse noise component.

In this way, the corresponding pixel can be excluded from the candidates for impulse noise according to the motion detection, and false detection of impulse noise in a moving image can be reduced. By the way, the impulse noise detection signal detected when the line correlation and the frame correlation are used as the detection means of the impulse noise used in the satellite broadcast receiver as described above, the impulse noise depends on the magnitude of the set threshold value. A difference appears in the effect of noise removal.

FIG. 36 shows an impulse noise detection signal when the magnitudes of the threshold values are different. In FIGS. 36 (a) and 36 (b), (a) is better than (b). The threshold value is large. Here, the hatched portion in FIG. 36 indicates the portion that remains without being removed when the impulse noise is removed. For convenience, this part will be called residual impulse noise. This residual impulse noise is reduced by reducing the threshold value as shown in FIG. 36 (b), and the effect of removing impulse noise is improved. However, this increases the probability of erroneously detecting a portion that is not impulse noise as impulse noise, and tends to cause erroneous detection distortion in the image after impulse noise removal, resulting in a deterioration in image quality. Therefore, even in the above-described noise removing circuit, the threshold value cannot be set to an infinitely small value, and there is a problem that some residual impulse noise must be accepted.

Description of Embodiments of Sixth Invention The sixth invention of the present application is to further improve the impulse noise removing effect by reducing the residual impulse noise after the impulse noise removal. An embodiment of the sixth invention shown in the drawings will be described below. Almost all tuners of satellite broadcast receivers use the PLL detection method. The waveform of impulse noise generated during the operation of this PLL detection method has a substantially uniform shape. If the waveform of impulse noise is almost constant, if the threshold value for impulse noise detection is set to a predetermined value, the impulse noise detection signal in that case will have a substantially constant time width. Therefore, if this threshold value is properly set, the time width of the false detection signal can be made smaller than the time width of the true impulse noise detection signal in most cases.

FIG. 37 shows a true impulse noise detection signal having time widths t1 and t2 and an error detection signal having time widths te1 and te2 when the threshold values are appropriately set as described above. In this case, when the average of the time widths of the true impulse noise detection signals is t, t≈t1≈t
2, the relationship of te1 <t and te2 <t is established.

Using this relationship, when the time width of the impulse noise detection signal becomes substantially equal to t, the time for impulse noise removal is extended to reduce the residual impulse noise, and when the time width is smaller than t. Is capable of reducing the residual impulse noise after impulse noise removal by creating a signal for performing control without special processing and replacing it with the impulse noise detection signal (medaka noise detection signal) of the previous application. Impulse noise removal with large noise can be performed.

FIG. 38 shows a residual impulse noise removing circuit which constitutes a main part of an embodiment of the impulse noise removing apparatus according to the sixth aspect of the present invention. In the figure, 360
Is an impulse noise detection signal, 362 is a system clock, 364 is a shift register, 366 is a shift register output, 468 is an AND circuit, 470 is an OR circuit, 372.
Is a D-type flip-flop, 374 is a clock input of the flip-flop, 376 is a Q output of the flip-flop, and 378 is an impulse noise elimination signal.

The residual impulse noise elimination circuit is inserted, for example, at the point AA 'of the noise reduction circuit shown in FIGS. 28 and 29. Noise reduction circuit 96
The impulse noise detection signal 360 output from the shift register 364, the AND circuit 368, and the OR circuit 3 is
70, the output from the AND circuit 368 becomes the clock input 374 of the flip-flop 372, and the shift register output 366 is given to the clear terminal bar CLR of the AND circuit 368 and the flip-flop 372, and its Q output 376 is It is added to the OR circuit 370. As a result, in each of the circuits, signal processing as shown in the timing chart of FIG. 38 is performed, and the detection time of the impulse noise detection signal 360 is set to a constant value, for example, the system clock 362 (that is, the sampling clock). When it is 5 cycles or more, it is determined that there is true impulse noise, and when it is less than 5 cycles, it is determined that it is an erroneous detection.

Table 1 shows a truth table of the flip-flop 72.

[0105]

[Table 1]

That is, in the impulse noise detection signal 360 on the timing chart of FIG. 38, the tn detection time width portion is the true impulse noise, and the te detection time width portion is the erroneous detection portion. The signal 378 is extended only when the detection time width of the impulse noise detection signal 360 is 5 cycles or more of the system clock 362. The extension time ta at this time is 5 cycles or more and less than 6 cycles of the system clock 362.

Although the shift register and the D-type flip-flop are used in this embodiment, the present invention is not limited to these, and any equivalent output can be obtained.
Any circuit may be used.

Description of Embodiment of Seventh Invention Now, the satellite tracking receiving apparatus or the like according to the first or second invention described above is provided with a synchronous clamp circuit for clamping a video signal normally received. .. The purpose of clamping the video signal by the synchronous clamp circuit is to reproduce the DC component lost by transmitting the video signal by capacitive coupling. Generally, the synchronous clamp circuit is shown in FIG.
As shown in 0, the TV monitor unit 3 is used in a satellite broadcast receiver or the like.
It is built in 92 and performs a synchronous clamp. In the figure, 381 is a satellite broadcast receiving antenna, 382 is an intermediate frequency conversion circuit, 383 is an IF signal, 384 is a tuner section, 385 is a video signal, and the TV monitor section 392 has a synchronous clamp circuit 393 and a TV monitor 394. ing.

However, impulse noise may occur in the synchronizing signal when the C / N is lowered due to rain attenuation or the like. In that case, the clamp level fluctuates and the synchronous clamping cannot be performed.

The seventh invention of the present application proposes a synchronous clamp circuit capable of performing synchronous clamp without being affected by the fluctuation of the clamp level due to such impulse noise. FIG. 41 shows an example of the synchronous clamp circuit. An example is shown. In the figure, 401 is an input video signal, R ₁ and R ₂
Is a bias resistor, 402 is a first NPN transistor,
The video signal input means is configured. Reference numeral 405 is a charging capacitor, and 408 is a discharge resistor, which constitutes the charging / discharging means. 410 is an amplifier, 412 is a low-pass filter (LP
F) and 414 are low frequency component image signals, which constitute the low frequency image component extracting means.

416 is a fourth NPN transistor, 418
Is its output signal, 420 is the fifth NPN transistor, 4
Reference numeral 22 is a switching current, 424 is a load resistance, and 426 is a switching signal (control signal), which constitutes the control signal generating means. A third PNP transistor 428 constitutes the charge / discharge control means. Reference numeral 430 is a video output signal. Further, RV is a variable resistor for generating the clamp voltage Er (clamp reference signal).

In the synchronous clamp circuit of FIG. 41, the input video signal 401 is biased by the power supply voltage + V and the resistors R ₁ and R ₂ and then made into a low impedance by the first transistor 402 connected to the emitter follower,
A clamp operation is performed by charging / discharging the charging capacitor 405.

[0113] Charging of the clamping operation, when the potential of the switching signal 426 is input to the base of the third transistor 428 becomes lower than the emitter voltage of the third transistor 428 (i.e. the supply voltage + V), the charging current I ₁ Flow into the charging capacitor 405. Regarding the discharge, the input current value r of the amplifier 410 is set to a negligibly smaller value than the resistance value R of the discharge resistor 408 to obtain the discharge current I ₂ with the above-mentioned discharge time constant T = RC. Done by

Next, the operation until the switching signal 426 for flowing the charging current I ₁ is generated will be described. The video output signal 430 is output as a video signal that is synchronously clamped as shown in FIG. 42, and is also input to the low-pass filter 412 via the amplifier 410. As its output, the low-frequency component video signal 4 in which impulse noise is smoothed is output.
14 are extracted. At this time, the amount of decrease in the level of the signal by the low-pass filter 412 is preliminarily determined by the amplifier 410.
(Or the clamp voltage may be adjusted in anticipation of this level decrease), and the low-pass filter 412 having a characteristic capable of sufficiently smoothing impulse noise without impairing the synchronizing signal. To use. For example, for impulse noise generated when the FM modulation method is used to modulate a video signal such as satellite broadcasting,
In the present embodiment, when the PLL demodulation method is used as the FM demodulation method, it is more effective to set the cutoff frequency fc of the low pass filter 412 to about 0.1 to 0.5 MHz.

The video output signal 43 is shown in FIGS. 33 (b) and 33 (c).
Examples of 0 and the low frequency component video signal 414 are shown. When the low-frequency component video signal 414 has a low impedance by the fourth transistor 116 and its output signal is applied to the emitter of the fifth transistor 420, the potential (synchronization signal level) of the output signal of the fourth transistor 416 is clamped by the clamp voltage Er. In the lower case, the switching current 422 flows, and the load resistor 424 causes the switching signal 426.
Will be generated. This switching signal 426
As a result, the third transistor 428 is driven so that the negative peak of the synchronizing signal of the output signal of the fourth transistor 416 is kept constant so as to have the potential of the clamp voltage Er. That is, the negative peak of the sync signal of the video output signal 430 can be clamped to the potential of the clamp voltage Er regardless of the presence or absence of impulse noise in the input video signal 401.

As described above, as the video output signal 430, a synchronously clamped video signal can be obtained without being affected by impulse noise.

Description of Embodiment of the Eighth Invention Now, in FM transmission of a video signal represented by satellite broadcasting, if C / N is lowered, impulse noise is generated in the demodulated video signal. FIG. 43 (a) shows the video signal when C / N is good, and FIG. 43 (b) shows the video signal when C / N is lowered, and as shown in FIG. When it occurs in the back porch portion of the video signal, the conventional pedestal clamp circuit has a drawback that the pedestal level is not clamped to the clamp level, and incorrect luminance information is displayed on the display image on the TV monitor. It was

The feature of the eighth embodiment of the present invention is that it can be applied to the first and second inventions in place of the above-described seventh embodiment of the invention. In this way, impulse noise is added to the video signal. In order to ensure that the pedestal clamp is normally performed on the television monitor when it occurs, the back porch portion of the video signal can be replaced with a signal having no impulse noise.

An embodiment according to the eighth invention shown in the drawings will be described below. FIG. 44 shows an embodiment of a synchronous clamp device for pedestal replacement processing according to the present invention, in which 501 is a BS tuner, 502 is a demodulated video signal, and 503 is a sync separation circuit.
The sync component signal extracting means is configured. Reference numeral 504 is a YC separation circuit, which constitutes the luminance component extraction means. Reference numeral 505 is a luminance signal, 506 is a chroma signal, and 507 is a synchronous clamp circuit, which constitutes the synchronous clamp means. Reference numeral 508 is a synchronous clamp luminance signal, 509 is a reference potential, and 510 is a switch circuit, which constitutes the pedestal replacement means.

The demodulated video signal 502 output from the BS tuner 501 is a sync separation circuit 503 and a YC separation circuit 5.
In 04, the luminance signal 505 and the chroma signal 506 are separated, and then the luminance signal 505 is input to the synchronous clamp circuit 507. In this embodiment, normal pedestal clamp is performed even if impulse noise occurs in the video signal.

In FIG. 44, the demodulated video signal 502 from the BS tuner 501 is input to the sync separation circuit 503 and the YC separation circuit 504, and a luminance signal 505, a chroma signal 506 and a back porch signal 511 are obtained. Luminance signal 5
05 is processed by the synchronous clamp circuit 507 and outputs the synchronous clamp luminance signal 508 to the switch circuit 510. The switch circuit 510 switches the reference potential 509 and the signal 508 based on the back porch signal 511, replaces the pouch portion of the signal 508 with the reference potential, removes impulse noise in that portion, and removes the pedestal replacement luminance signal 512. To the YC mix circuit 513 to output the chroma signal 5
06 and the pedestal-replaced video signal 514 is supplied to the television monitor 515. As a result, the porch portion of the luminance component signal is replaced with the level of the reference signal, and the impulse noise component existing in the porch portion is removed.
Note that, as the synchronous clamp circuit 507, for example, FIG.
The circuit shown in is used.

As described above, the sync clamp circuit 507 outputs the sync clamp luminance signal 508 in which the negative peak of the sync signal is clamped to a constant potential without being affected by the impulse noise. At this time, the potential difference between the negative peak of the sync signal of the sync clamp luminance signal 508 and the pedestal level (potential of the back porch portion) is always a substantially constant value. The reason is firstly, for example, the journal of the Television Society of Japan, Vol. 44, No. 2 As disclosed on pages 169 to 172, since the video signal transmitted from the broadcasting station complies with the RS170A standard of the US EIA, the level difference between the negative peak of the synchronization signal and the pedestal level is 4
This is because the level of the demodulated video signal 502 demodulated by the BS tuner 501 is maintained substantially constant by the AGC.

Since the negative peak of the sync signal is clamped to a constant potential and the potential difference between the negative peak of the sync signal and the pedestal level is almost constant, the pedestal level of the sync clamp luminance signal 508 is impulsive noise. It means that a constant potential is maintained regardless of the presence or absence of.

Next, this will be described with reference to FIG. For example, if the potential of the sync clamp level is e _c and the potential difference between the negative peak of the sync signal and the pedestal level is e _o , the pedestal level of the sync clamp luminance signal 508 is maintained at the potential of e _c + e _o . Here, as shown in FIG. 44, if a reference potential 509 having a DC potential of e _c + e _o is prepared and only the back porch portion of the synchronous clamp luminance signal 508 is replaced with the reference potential 509 by the switch circuit 510, The pedestal-replacement luminance signal 512 from which impulse noise has been removed can be obtained from the back porch portion. At this time, the back porch signal 511 for controlling the switch circuit 510 can be easily obtained from the sync separation circuit 503. The pedestal replacement luminance signal 512 and the chroma signal 506 are combined in the YC mix circuit 513 to obtain a pedestal replacement video signal 514. When the pedestal-replaced video signal 514 is supplied to the television monitor 515, normal luminance information is displayed without being affected by impulse noise.

As described above, according to the embodiment, the BS
In FM transmission of video signals typified by broadcasting, C / N
The pedestal clamp is performed normally without being affected by the impulse noise by selecting even if impulse noise occurs in the demodulated video signal due to its low noise, so the luminance information is faithfully reproduced in the image displayed on the TV monitor. can do.

[0126]

As described above, according to each invention of the present application, the following excellent effects can be obtained. (I) According to the first aspect of the present invention, it is possible to provide a simple and inexpensive structure that has sufficient responsiveness to withstand a drastic posture change of the moving body. (Ii) According to the second aspect, the angular velocity sensor can be calibrated, and the antenna can be directed toward the satellite even when the radio wave is shielded by the inexpensive angular velocity sensor, and the satellite can be captured immediately after the shield is released. (Iii) According to the third invention, based on the information of the angular velocity in the azimuth direction of the moving body and the information of the change of the reception level,
The two axes of elevation and azimuth can be controlled in a time-sharing manner. (Vi) According to the fourth invention, even if the C / N of the received signal is lowered and the impulse noise is generated in the video signal to impair the quality of the displayed image, the impulse noise is detected and removed. The deteriorated image quality can be remarkably improved. (V) According to the fifth aspect of the present invention, it is possible to reduce image distortion due to erroneous detection of impulse noise in a specific frequency region of a moving image to a level at which it does not visually interfere. (Vi) According to the sixth aspect of the present invention, residual impulse noise can be reduced without increasing false detection of impulse noise. (Vii), (Viii) According to the seventh and eighth aspects of the present invention, even if impulse noise occurs in the sync signal of the video signal, the sync clamp is performed without being affected by the impulse noise. You can

[Brief description of drawings]

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

FIG. 2 is a characteristic diagram showing a relationship between an angular velocity of an angular velocity sensor and an output voltage.

FIG. 3 is an explanatory diagram showing a state of actual control according to the embodiment of FIG.

FIG. 4 is a waveform diagram for explaining the operation of switching the rotation speed of a motor when turning a right curve.

FIG. 5 is a block diagram showing a conventional phase monopulse system.

6 is a waveform diagram for explaining the operation of the system of FIG.

7 is a characteristic diagram of a DC signal sin ψ in the system of FIG.

FIG. 8 is a block diagram showing a conventional amplitude monopulse system.

9 is an output characteristic diagram of two level detectors in the system of FIG.

10 is a characteristic diagram showing a drive voltage of a motor in the system of FIG.

FIG. 11 is a block diagram showing a conventional step track method.

FIG. 12 is a block diagram showing an embodiment of the second invention of the present application.

FIG. 13 is an explanatory diagram showing an actual control state according to the embodiment of FIG.

14 is a waveform chart for explaining the operation of the embodiment in FIG.

FIG. 15 is a block diagram showing a configuration example of a triangular wave generation circuit.

FIG. 16 is a block diagram showing an embodiment of the third invention of the present application.

FIG. 17 is a block diagram showing a configuration example of a level change detection circuit.

FIG. 18 is a waveform diagram for explaining the operation of the level change detection circuit.

FIG. 19 is a block diagram showing a configuration example of a speed setting unit.

FIG. 20 is a timing chart for explaining the operation of the speed setting unit.

FIG. 21 is a block diagram showing a configuration example of an angular velocity sensor correction circuit in the velocity setting unit.

FIG. 22 is a waveform diagram for explaining the operation of the circuit when actually controlling the elevation angle.

FIG. 23 is an explanatory diagram showing a state of actual control of an azimuth angle.

FIG. 24 is a time chart for explaining the control of the azimuth angle.

FIG. 25 is a block diagram showing a configuration example of a drive motor switching unit in the above-mentioned embodiment.

FIG. 26 is a time chart for explaining the operation of the drive motor switching unit.

FIG. 27 is a block diagram of an embodiment of a television receiving device including a noise removing circuit according to a fourth invention of the present application.

28 is a block diagram illustrating a schematic configuration of the noise reduction circuit of FIG. 27.

29 is a block diagram of an embodiment of the noise reduction circuit of FIG. 27. FIG.

FIG. 30 is a diagram illustrating the principle of detecting medaka noise according to the fourth invention.

FIG. 31 is a diagram showing a frequency region in which erroneous detection occurs in the fourth invention.

FIG. 32 is an explanatory diagram of a motion detecting method according to a fifth invention of the present application.

[Fig. 33] Fig. 33 is a block diagram illustrating a principle configuration for implementing the above-described motion detection method.

FIG. 34 is a block diagram showing an embodiment of the fifth invention of the present application.

FIG. 35 is a block diagram showing another embodiment of the fifth invention of the present application.

FIG. 36 is a waveform diagram showing a relationship between a threshold value and an impulse noise detection signal.

FIG. 37 is a waveform diagram showing an impulse noise detection signal.

FIG. 38 is a block diagram showing an embodiment of the sixth invention of the present application.

39 is a timing chart for explaining the operation of the circuit of FIG. 38. FIG.

FIG. 40 is a block diagram showing a conventional satellite broadcast receiver.

FIG. 41 is a block diagram showing an embodiment of the seventh invention of the present application.

42 is a waveform chart for explaining the operation of the embodiment in FIG. 41. FIG.

FIG. 43 is a waveform diagram showing a pedestal clamp when impulse noise occurs.

FIG. 44 is a block diagram showing an embodiment of the eighth invention of the present application.

45 is a waveform chart for explaining the operation of the embodiment in FIG. 44.

[Explanation of symbols]

 51 turntable 52 motor 53 antenna 54 frequency converter 55 level detector 56 level change detector 57 switch 58 angular velocity sensor 59 adder 60 motor drive circuit 61 demodulation circuit 62 monitor

Claims (8)

[Claims] 1. A frequency conversion means for converting a reception signal from an antenna provided in a mobile body into a predetermined frequency signal, detecting a deviation of the antenna with respect to a satellite direction based on the frequency signal, and detecting the deviation based on the detection result. In a satellite tracking receiver of a mobile antenna for driving and controlling the direction and rotation speed of the antenna so as to track the satellite, the antenna is single and a level change detection signal is detected by detecting a level change of a frequency signal from the antenna. A level detection means for outputting the angular velocity of the moving body, an angular velocity detection means for detecting a satellite direction and outputting an angular velocity detection signal, and a calculation based on the level change detection signal and the angular velocity detection signal And the arithmetic processing means for changing the rotational speed of the antenna according to the addition result and switching the direction to track the satellite. Satellite tracking receiver of mobile antenna, characterized in that it comprises a. 2. A first control signal output means for inputting a level change detection signal from the level detection means and outputting a predetermined first control signal according to a level change of the signal, and the level change detection signal. Second control signal output means for inputting and outputting a predetermined second control signal according to the level of the signal, the first control signal and the second control signal being based on the level change detection signal. 2. The movement according to claim 1, wherein the detection deviation in the angular velocity detecting means is calibrated so that the signal is output as a signal to the arithmetic processing means and added, and the addition result is substantially the same as the true angular velocity. Satellite tracking receiver for body antenna. 3. An angular velocity zero detection unit that detects that the angular velocity of the moving body is substantially zero based on an angular velocity detection signal from the angular velocity detection unit and outputs a zero angular velocity signal, and a level detection unit that outputs the angular velocity zero signal. A level change detection signal and the zero angular velocity signal are input, and the satellite is tracked by a time division control signal that alternately controls the elevation angle and the azimuth angle of the antenna at predetermined time intervals based on the both signals. The satellite tracking receiver for a mobile antenna according to claim 1, further comprising: time division control means. 4. A demodulation unit that demodulates the frequency signal from the frequency conversion unit and outputs a video signal including a detection signal and luminance information, a noise component included in the detection signal, and the noise component amount is detected. Noise detection / determination means for determining the presence / absence of an impulse noise component having a large single-shot luminance change included in the video signal based on the noise detection / determination means, and the noise determination signal, when there is the impulse noise component, A noise for outputting an image signal from the demodulating means when an impulse part in the image signal is detected and the luminance of the part is interpolated to output an image signal from which the impulse noise component is removed. The satellite tracking receiver for a mobile antenna according to claim 1, further comprising: a detecting / removing unit. 5. A frame difference component extracting means for extracting a frame difference component signal from a video signal including the luminance information and a signal obtained by delaying the video signal for a predetermined frame period, the frame difference component signal and a predetermined reference signal. And a motion detection unit that detects the presence or absence of motion in vertically adjacent pixels in the same field and outputs a motion detection signal based on the comparison result, and motion detection is performed by the motion detection signal. The impulse noise determining unit determines that the impulse noise component does not exist only when the noise is detected, and the output of the noise detecting / removing unit is only the video signal from the demodulating unit. A satellite tracking receiver for a mobile antenna as described above. 6. The noise detecting / removing means, when detecting the impulse part, determines that the detection time is a residual impulse noise when the detection time is a predetermined time or more based on a control signal of a predetermined cycle, and determines the residual impulse noise. The movement according to claim 4 or 5, further comprising residual impulse noise removing means for extending the detection time based on the cycle so as to remove the residual impulse noise and outputting an impulse noise removal signal having the extended detection time. Satellite tracking receiver for body antenna. 7. The video signal includes an impulse noise component in a sync signal, which charges the video signal,
A charging / discharging means for obtaining a video output signal that is discharged and synchronously clamped based on the synchronizing signal, a clamp reference signal generating means for generating a reference signal for performing the clamping operation, and the charged video signal are input. A low-frequency image component extracting means for smoothing an impulse noise component contained in the synchronization signal and outputting it as a low-frequency component image signal; and a difference between the synchronization signal level of the low-frequency component image signal and the clamp reference signal level. A control signal generation unit that generates and outputs a predetermined control signal in response to the control signal, and based on the control signal, the charging / discharging unit is charge-controlled so that the synchronization signal level becomes the reference signal level, and noise components are removed. 7. A satellite tracking receiver for a mobile antenna according to claim 1, 4 or 6, further comprising: a charge / discharge control means for obtaining a video output signal. . 8. A luminance component extraction means for obtaining a luminance component signal from the video signal containing an impulse noise component, a synchronization component signal extraction means for extracting a synchronization component signal from the video signal, and a negative component of the luminance component signal. The clamp control is performed at a level such that the potential difference between the peak and the pedestal level becomes a predetermined value, and a synchronous clamp means for obtaining a luminance component signal of a constant pedestal level, a reference signal generated at a level substantially the same as the pedestal level, and A clamp-controlled luminance component signal is switched based on the synchronization component signal, the porch portion of the luminance component signal is replaced with the level of the reference signal, and the impulse noise component existing in the porch portion is removed. A pedestal replacement means, and a satellite tracking for a mobile antenna according to claim 1, 4, or 6. The receiving device.