JPH0460479A - Broadcasting satellite mobile receiver - Google Patents

Abstract

PURPOSE:To make an automatic tracking of the highest strength azimuth possible by providing an envelope-detecting measure of a satellite broadcasting receiving antenna measure, a measure to revolve the antenna measure judging between heights of a receiving field strength, etc. CONSTITUTION:An antenna device 18 is provided on a revolving mechanism 19, and a gyroscope 24 is set up in the mechanism 19 and generates a voltage according to a revolving angular velocity of the device 18. A servo motor 20 is driven by an output of an adding circuit 32 increased through a servo amplifier 21 and the mechanism 19 is revolved. The output of the device 18 is detected by an envelope-detecting circuit 22, the detected output is given to the first voltage comparator 27 to be compared with a reference voltage and the mode is judged. An electronic switch 30 is connected to a contact point (a) and an output signal of a low-frequency oscillator 31 is inputted to one side of the adding circuit 32, if it is the first mode. The adding output of the circuit 32 becomes positive if the reference wave and the receiving electric field of the device 18 are the same and the motor 20 is vibrated and rotated to a prescribed direction through a servo amplifier 21.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a mobile broadcasting satellite receiver, and more particularly to an improvement in a simple and inexpensive tracking system for broadcasting satellites.

[Summary of the Invention] A broadcasting satellite mobile receiving device that tracks a broadcasting satellite by means of an antenna means consisting of a plurality of antenna elements,
When the received electric field strength is high, tracking is performed by rotating the antenna means with slight vibrations, and when the received electric field strength is low, the antenna means is rotated in a predetermined direction by an integral signal of the output of a gyro that is linked to the rotation. It is something that makes you

[Prior Art] The following systems have been proposed for devices that receive radio waves from broadcasting satellites while moving.

(i) The antenna is divided into a plurality of blocks and the output of each block is combined as the output of a converter having the same frequency, thereby expanding the directivity of the antenna and improving the CN ratio.

(11) Measure the arrival time of radio waves from multiple antennas, calculate the antenna deflection angle using a monopulse corresponding to this time, and use the servo system to track the antenna to the broadcasting satellite so that this deflection angle becomes ○. . This tracking is performed with respect to the azimuth and elevation angles of the antenna.

(River) A gyro is attached to the antenna, and the gyro can track the broadcasting satellite even if it enters a tunnel or the shadow of a building.

[Problems to be Solved by the Invention] However, according to the method (i), not only a special converter is required, but also the synthesis circuit becomes complicated.

Further, the method (u) requires a monopulse circuit. Furthermore, the method (iii) requires a microcomputer to determine whether to use the antenna output or the gyro output to detect the orientation of the antenna, resulting in a complicated configuration.

[Object of the Invention] Accordingly, an object of the present invention is to enable mobile reception of a broadcasting satellite using an output signal of an antenna and an output of a gyro with a simpler configuration than the conventional one.

[Means for Solving the Problems] In order to achieve the above object, a broadcasting satellite mobile receiving device according to the present invention includes a satellite broadcasting receiving antenna means including a plurality of antenna elements, and detecting an envelope of an output signal of the antenna means. means for causing the antenna means to track a broadcasting satellite; means for comparing the output signal of the envelope detection means with a reference signal; and a signal obtained by synchronously detecting the output signal of the envelope detection means using the signal, and means for applying the signal to the tracking means to rotate the antenna means while slightly vibrating the antenna means, and the receiving electric field strength is determined to be low by the comparison means. In this case, the gist includes means for applying a signal obtained by integrating the output of a gyro interlocked with the antenna means to the tracking means to rotate the antenna means in a predetermined direction.

[Operation] The envelope of the antenna output is detected, and if the received electric field strength is high, the azimuth servo system is driven to rotate the antenna while causing slight vibrations. When the received electric field strength is low, the output of the gyro linked to the antenna is integrated, and the integrated signal is used to drive the servo system.

Embodiments The present invention will be described below with reference to embodiments shown in the drawings. FIG. 1 shows an embodiment of a broadcasting satellite mobile receiver according to the present invention. In the figure, 18 is an antenna device, 19 is an antenna device rotation mechanism, 20 is a servo motor, 21 is a servo amplifier, 22 is an envelope detection circuit, 23 is a multiplication circuit, 24 is a gyro, 25 is an integration circuit, and 27 is a first A voltage comparator, 28 is a first reference voltage source, 29 is a low-pass filter, 30 is an electronic switch, 31 is a low frequency oscillator, 32 is an adder circuit, 33 is a second voltage comparator, 34 is a second reference voltage source .

The antenna device 18 is configured as shown in FIGS. 2 and 3, for example.

Since the present invention is based on simple reception, the condition is that the road condition is good and the vehicle travels on a substantially flat surface.Therefore, as shown in FIG. 4, each position of the planar antenna element ANT is It is assumed that the elevation angle φ with respect to the broadcasting satellite is always constant at X, .

In reality, the directivity of the antenna is broadened to enable reception even on somewhat uneven surfaces or on gentle slopes.

For example, if eight planar antenna elements A8 to D3 are integrated into four sets of planar antennas, two each of which is shown in FIG. 2, the directivity will be as shown by the solid line in FIG. Although the angle is ±1 degree, the directivity of each antenna element is spread out as shown by the broken line. Therefore, if the outputs of each set of antenna elements are combined, the gain will be large and the directivity will be wide.

Further, the advantage of having the antenna in a split configuration is that the height H of the antenna is reduced, which is often convenient when attaching it to a moving object.

FIG. 3 shows an example of an output combining circuit for different IF frequencies of the pair of antenna elements A, .

In the figure, ■ and 7 are antenna outputs, 2°4.8 and 10 are frequency converters, 3 and 9 are first local oscillators, 5 and 11 are second local oscillators, 6 and 12 are IF bandpass filters, and 13 14 is a multiplication circuit, 14 is a band pass filter, 15 is a 1/2 frequency downshift circuit, and 16 is a band pass filter.

The output 1 of the antenna element A1 is given to the frequency converter 2 together with the output of the first local oscillator 3 and converted to a lower frequency, and the converted output is also given to the frequency converter 4 together with the output of the second local oscillator 5. For example 400MHz
The signal is converted to an IF signal of the band, and excess frequency components are removed by a bandpass filter 6. Similarly, for the output of the antenna element A, the output of the bandpass filter 12 is a 400MHz band ■F from which extra frequency components have been removed.
You can get twice the signal.

The outputs of the frequency converters 6 and 12 are applied to a multiplier circuit 13, and a band pass filter 14 extracts an 800 MHz frequency component from the output, which is converted into a 400 MHz band FM signal by a 172 frequency down-down circuit 15 consisting of flip-flops and the like. Furthermore, if necessary, a combined output of antenna elements A1 and A is obtained through a 400 MHz bandpass filter 16.

Similar output combining can be performed for other sets of antenna elements B, B, . . . D, D, or output combining of antenna elements A, B, C, D, etc. , A, , B, and C, , D can be combined in the same way.

The device of the present invention uses a gyro in combination with an automatic tracking servo system for the electric field strength of the antenna input to maintain the orientation of the antenna in the direction of the broadcasting satellite when the electric field decreases in a tunnel or in the shadow of a building. With the configurations shown in Figures 2 and 3, a relatively wide directivity for receiving broadcasting satellites can be obtained by only in-plane rotation of the antenna, and when the received electric field strength is high, the antenna can be rotated by minute vibrations to move toward the highest direction of the received electric field. The first mode automatically tracks the antenna, and the second mode keeps the antenna azimuth constant using the output of the gyro when the received field strength is low.

The antenna device 18 is mounted on the rotating machine $19,
A gyro 24 is installed in this rotation mechanism and generates a voltage according to the rotational angular velocity of the antenna device 18.

The rotating machine @19 is rotated by driving the servo motor 20 with the output of the adding circuit 32 applied via the servo amplifier 21. In the first mode, the input signal to the adder circuit 32 consists of a DC component that changes the azimuth of the antenna to maximize the electric field strength, and a signal that gives a minute rotational vibration of the antenna to search for the highest electric field, and in the second mode Now Gyro 2
This is a signal obtained by integrating the output of 4.

The above mode is determined by detecting the output of the antenna device 18, for example, by the IF multiplied signal envelope detection circuit 22 output from the bandpass filter 6 in FIG. This is done by comparing with a reference voltage Er. That is, if it is determined by this comparison that the received electric field strength is strong, the electronic switch 3° becomes the first mode and selects contact a, and if it is determined that the received electric field strength is weak, it becomes the second mode. Then, the electronic switch 30 selects the contact point.

Now, in the first mode, the eleventh switch 30 is connected to contact a, and the output signal (fundamental wave C
O8ω,1) is applied to one input terminal of the adder circuit 32. The output signal of the antenna device ] 8 is envelope-detected by an envelope detection circuit 22 , and the detected output is multiplied by the fundamental wave COS ω, L by a multiplier circuit 23 , and the product component is extracted via a low-pass filter 29 . [The stream is obtained and applied further through an electronic switch 30 to the other input terminal of the summing circuit 32.]

If the fundamental wave cosω, t and the received electric field of the antenna device 18, which is the envelope detection output, are in phase, the addition output of the adder circuit 22 becomes positive and moves the motor 20 via the servo amplifier 21 in the direction of cosω, and -1. Vibrate and rotate. On the other hand, if the phase is reversed, the addition output is negative and the remoter 20 is COSω. When the antenna device 18 is vibrated and rotated in the direction of 1 and 1, and as a result, the added output converges to zero, the orientation of the antenna device 18 coincides with the broadcasting satellite.

FIG. 6 shows changes in the received electric field strength and the IF output level of the antenna device 18. (a) of the figure shows an envelope detection output corresponding to the received electric field strength, and the period up to t=ta-tB is lower than the reference voltage Er, and is the period of the second mode. FIG. 6(b) shows the mode selection of the electronic switch 30. In addition, FIG. 6(c) shows the rotation angle of the antenna by enlarging the time axis. In this (C), the broken line tB-tB is the second mode of control by the gyro. After tB shown by the solid line, the received electric field strength is sufficiently strong, and as described above, the motor 20 is in the first mode controlled by the antenna output. In this mode, fez is set at an antenna rotation angle of △θ.
It is vibrating. FIG. 6(d) shows the envelope detection circuit corresponding to the antenna output, and the IF level converges at a high point, that is, the highest value of the electric field received from the broadcasting satellite.

Next, in the second mote, the output signal of the shy c724 is integrated by the integrating circuit 25, and the motor 20 is driven by the integrated output.

Generally, the output of a gyro is a rotational angular velocity dθ/dt. Therefore, by integrating this gyro output by the integrating circuit 25, θ=f0 (here) dt, and the integrated output becomes the rotation angle θ.

FIG. 7 shows the time change of the gyro output with respect to the rotation angle of the antenna. Figure 7(e) Rotation of the antenna relative to the broadcasting satellite, for example, angle θ when a moving object changes direction
shows. The figure (f) shows the gyro output dθ/dA at this time.
shows. The figure (g) also shows the integral output θ.

The integrated output of the integrating circuit 25 is sent to the comparator 33, and the reference voltage Er
, and the comparison output is applied to the adder circuit 32 and the servo amplifier 21 via the b contact of the electronic switch 30 to drive the servo motor 20. By setting Er,=O, the deflection angle θ of the antenna can be maintained at 0. FIG. 7(h) shows the deviation of the antenna from the broadcasting satellite in such a state.

Assuming that the servo system operates in Fig. 7(e), (f), and (g), the integral value θ1 for the period 1 to 1 in Fig. 7(f) is td θ θ, = f, ° < -70=)d, the integral output corresponding to the shaded area in (f) is fed back to the servo system, and the motor 20 is driven so that 01 in (g) becomes zero.

[Effects of the Invention] As explained above, according to the present invention, the output of the antenna device and the gyro output are combined to drive the servo motor for rotating the antenna device. The azimuth angle of the antenna device can be held constant, and when the received electric field strength becomes strong, radio waves from the broadcasting satellite can be immediately received.

When the electric field strength is strong, it is possible to automatically track the azimuth angle of the highest strength due to vibration rotation of the antenna device and continuously receive radio waves from the broadcasting satellite.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIGS. 2 and 3 are diagrams showing an example of an antenna device, FIG. 4 is a diagram showing antenna elevation angles for mobile reception of a broadcasting satellite, and FIG. 5 is a diagram showing an example of an antenna device. is a diagram showing the directivity of the antenna, and FIGS. 6 and 7 are waveform diagrams for explaining the operation of the above embodiment. 18...Antenna device, 19...
...Rotating mechanism, 20... Servo motor, 22... Envelope detection circuit, 23
・・・・・・・・・Multiplication circuit, 24・・・・・・・・・
Gyro, 25... Integral circuit, 27.3
3・・・・・・Comparator, 30・・・・・・・・・
Electronic switch, 31...Low frequency oscillator,
32...Addition circuit.

Claims (1)

[Scope of Claims] Satellite broadcast receiving antenna means including a plurality of antenna elements; means for detecting an envelope of an output signal of the antenna means; means for causing the antenna means to track a broadcasting satellite; means for comparing the output signal with a reference signal; and when the received electric field strength is determined to be high by the comparison means, the signal of a predetermined frequency and the signal obtained by synchronously detecting the output signal of the envelope detection means with the signal are tracked. a means for rotating the antenna means while causing minute vibrations; and means for rotating the antenna means in a predetermined direction.