JP3845280B2 - Directional direction control device for phased array antenna - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
It is a technology that uses beacon radio waves to direct the main beam irradiation direction of the target antenna in a predetermined direction with high accuracy, and is a phased array used for antennas mounted on artificial satellites, synthetic aperture antennas, antennas mounted on ships, etc. Related to antenna.
[0002]
[Prior art]
FIG. 5 shows an example of the configuration of a conventional antenna directivity direction control device. The purpose of this example is to control the directivity of the antenna mounted on the satellite with high accuracy. A communication station 6-1 and a communication station 6-2 that communicate via this satellite are arranged in a predetermined area on the ground irradiated by this antenna, and communication waves 9-1 and 9-2 are radiated from these stations, respectively. ing.
[0003]
In addition, a beacon wave 8 is radiated from a ground beacon station 7 toward the same satellite in a predetermined area of the satellite-mounted antenna. In the equipment configuration mounted on the satellite, 1-1, 1-2, 1-3, 1-4, 1-n are n antenna elements of the antenna feeding unit, and four antennas 1-1 to 1-4 are provided. The element is an antenna element for receiving the communication waves 9-1 and 9-2 and detecting the antenna pointing error.
[0004]
Reference numeral 2-1 indicates that the signal of the antenna cord 1-1 that simultaneously receives the communication wave received by the antenna element and the beacon wave 8 is branched into the communication signal 10-1 and the sensor signal 11-1 used for detecting the directivity. It is a waver. Similarly, the same type of duplexers are provided on the output sides of the antenna elements 1-2, 1-3, and 1-4, respectively.
[0005]
For other antenna elements including 1-n not used for pointing error detection, the output is the communication signal 10 as it is. Reference numeral 3 denotes a sensor beam forming circuit that forms a fixed beam pattern from four sensor signals. Reference numeral 4 denotes a sensor low noise amplifier that amplifies the output of the sensor beam forming circuit. Reference numeral 5 denotes an orthogonal biaxial pointing error signal. It is a sensor processing circuit that generates X12-1 and Y12-2.
[0006]
FIG. 6 is a diagram for explaining a conventional method of detecting a pointing direction error. In the same figure, the four antenna elements with numerals 1-1 to 1-4 are square-shaped, spaced by 90 degrees so that the two elements face each other as a set, and the center lines of the two elements are orthogonal to each other. Is arranged. 13-1 is one X error direction of the orthogonal center line, and the error in the direction is obtained as an output error signal X12-1 from the sensor processing circuit. Similarly, 13-2 is a Y error direction, and an error in this direction is obtained as an error signal Y12-2 as an output from the sensor processing circuit.
[0007]
When the antenna elements 1-1, 1-2, 1-3, 1-4 mounted on the satellite are accurately oriented in the direction of arrival of the beacon wave, error signals 12-1 and 12 in the X and Y directions are used. -2 is set to 0, and when the direction of the feeding element is deviated from the beacon arrival direction due to a change in the attitude of the satellite, error signals X and Y are output according to the deviated angle. Can be detected.
[0008]
[Problems to be solved by the invention]
Phased array antennas are indispensable for beam scanning, and have begun to be used mainly for terrestrial mobile communication base station antennas and satellite-mounted antennas aiming for higher functionality. However, when the irradiation area angle is relatively small and the pointing direction is greatly impaired due to factors other than the antenna feeder itself, such as a satellite-mounted antenna, the basic antenna performance such as antenna gain and isolation is greatly degraded. Eventually causes problems in communication performance.
[0009]
In order to solve this problem, it is necessary to control the pointing direction with high accuracy by control based on the arrival direction of the beacon wave radiated from the beacon station installed in the antenna irradiation area. However, detection of the directivity direction with respect to beacon waves has become indispensable.
[0010]
When the configuration of the conventional directivity direction embodiment shown in FIG. 5 is applied to this phased array antenna, signals of only four antenna elements are used from the many antenna elements of the phased array antenna in which beams are formed by all antenna elements. As a result, a sufficient signal-to-noise ratio cannot be ensured, and high-precision pointing error detection is impossible.
[0011]
Also, in phased array feeding, it is necessary to input the output signals of all feeding elements to the beam forming circuit in consideration of multiple line phases between both devices for beam formation. The increase in the phase deviation due to the branching of the sensor signal only caused the deterioration of the basic characteristics of the antenna.
[0012]
[Means for Solving the Problems]
According to the present invention, the above-described conventional problems are solved by the means described in the claims. That is, the invention of claim 1 is connected to a plurality of antenna elements for receiving communication waves and beacon waves from one beacon station, a plurality of amplifiers combined with each of the plurality of antenna elements, and the plurality of amplifiers. A variable beam forming circuit that receives the communication wave with a beam formed by controlling the amplitude and phase of each path and outputs a communication signal ; and the plurality of antenna elements provided in the variable beam forming circuit. And the beacon signal obtained by the plurality of amplifiers are combined and output along a predetermined excitation distribution , and an excitation distribution for forming three or more different beam patterns in the additional circuit is sequentially formed. an excitation distribution output circuit for inputting, gain contours of the beam pattern from the additional circuit output in response to the input excitation distribution from該励oscillation distribution output circuit Phased to the sensor processing circuit for outputting a direction and pointing error signal biaxial directions orthogonal X error direction and the Y error direction corresponding to both positions between the angle from the reference position of the Waru beacon position, in that it has features This is an array antenna directivity direction control device.
[0013]
According to a second aspect of the present invention, in the directivity control apparatus for the phased array antenna according to the first aspect, as an excitation distribution for forming different beam patterns, at a measurement point separated from the center of the beam (reference beam) by a certain angle, An excitation distribution that forms a plurality of beam (array antenna directivity) patterns having different sensor sensitivities represented by a ratio between an antenna gain and an angle is input.
[0014]
According to a third aspect of the present invention, in the directivity control apparatus for the phased array antenna according to the first aspect, as the excitation distribution for forming different beam patterns, the same sensor sensitivity is obtained from the angle from the center of the beam (reference beam). Are configured to input excitation distributions that form a plurality of beam patterns (array antenna directivity) having different measurement points.
[0015]
According to a fourth aspect of the present invention, in the second aspect of the present invention, the beam pattern having a high sensor sensitivity is formed in the additional circuit when the variation in pointing error is fast, and the variation in the pointing error is slow and When the fluctuation range is large, an excitation distribution that forms the beam pattern with low sensor sensitivity is input.
[0016]
As described above, in the phased array antenna according to the present invention, an additional circuit capable of forming a beam pattern for detecting a pointing error is added to a variable beam forming circuit already prepared for communication equipment. Then, a plurality of different excitation distributions are sequentially input to the additional circuit to form a control beam pattern capable of detecting a pointing error, beacon waves received by all antenna elements are input to the additional circuit, A two-axis pointing error signal is obtained by a sensor processing circuit using the output, and high-precision pointing control can be realized.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a first example of an embodiment of the present invention. This example shows the case where the present invention is applied to a phased array antenna mounted on a satellite, and corresponds to the invention of claim 1. In the figure, numeral 7 is a beacon station installed on the ground, 8 is a beacon wave, and this arrival direction is used as a reference for the direction of the phased array antenna.
[0018]
1-1, 1-2, and l-m are m antenna elements, and in the same antenna performance, the number m of antenna elements of the phased array antenna is larger than the number n of elements of the conventional antenna, and in some cases 10 times. That's it. 4-1, 4-2 and 4-m are m low-noise amplifiers, one for each antenna element.
[0019]
Reference numeral 14 is a variable beam forming circuit that forms a beam by controlling the phase and amplitude of the output signals of all the m systems of the low noise amplifiers along a predetermined excitation distribution.
[0020]
The variable beam forming circuit has a phase shifter and a gain variable for each of the m number of paths, and controls the phase and amplitude of each path to form a plurality of different beam patterns. The communication signal 10 is obtained by receiving the communication waves 9-1 and 9-2.
[0021]
15 is an additional circuit provided in the variable beam forming circuit, and has a function of inputting signals of all power feeding systems and outputting them along the set excitation distribution in the same manner as the circuit for obtaining the communication signal. Have.
[0022]
Reference numeral 16 denotes an excitation distribution output circuit for transmitting an excitation distribution of phase and amplitude corresponding to a plurality of different beam patterns. Reference numeral 5 denotes a sensor processing circuit having a function of outputting a directivity error signal of two orthogonal axes with outputs from a plurality of beam patterns output from the variable beam forming circuit 14 as inputs.
[0023]
In addition, a configuration is also possible in which the excitation distribution output circuit and the sensor processing circuit are mounted in the same housing to form one device so that the output of the excitation distribution and the input to the processing circuit are synchronized, and the weight of the entire circuit is reduced.
[0024]
FIG. 2 shows an example of a pointing error detection method for the beacon arrival wave direction of the antenna having the configuration shown in FIG. In the figure, reference numerals 17-1, 17-2, and 17-3 denote reference beams 1, 2, and 3 in different antenna patterns formed by excitation distributions sequentially input to the additional circuit, and the same antenna in each pattern. It represents the contour of the gain level.
[0025]
This contour line is substantially circular, and the gain decreases as the distance from the center of the circle increases. In this description, it is assumed that the gains on the three antenna patterns when the antenna feeding element is accurately oriented in the direction of arrival of the beacon are located at the same reference position 24 from the center of the three circles. Assuming that the beacon wave gains in the respective beam patterns are 18-1, 18-2 and 18-3, the beacon position 25 where the contour lines of the respective gains meet the actual arrival direction of the beacon wave.
[0026]
The sensor processing circuit 5 can obtain the pointing error signal X in the X error direction 13-1 and the pointing error signal Y in the Y error direction 131 according to the direction of the beacon position from the reference position 24 and the angle between both positions. I can do it. As another pointing error detection method to which this claim is applied, the pointing error signal X in the X error direction and the pointing in the Y error direction are generated by forming four beam patterns around the reference position and outputting the two patterns opposite to each other. It is also possible to generate the error signal Y.
[0027]
In this way, by detecting the beacon wave sensor signal using the signal synthesized from the output signals from all the antenna elements, the signal-to-noise ratio of the beacon wave is increased and the error in detecting the pointing error is suppressed. Since high accuracy can be achieved and an arbitrary antenna pattern can be input, a configuration with high versatility and easy design change can be realized.
[0028]
Further, since the pointing error is detected by the additional circuit without changing the configuration of the conventional phased array antenna, it can be realized without affecting the characteristics of the communication antenna. Further, the detection result of the pointing error can be freely acquired even during operation.
[0029]
Further, in a phased array power feed composed of a large number of antenna elements and the same number of low-noise amplifiers, there is no need for demultiplexing in the middle of the line from the feed elements to the variable beam forming circuit, so that antenna characteristics are not deteriorated.
[0030]
FIG. 3 is a diagram showing a second example of the embodiment of the present invention, and corresponds to the invention of claim 2. In the figure, reference numeral 13-1 is the X error direction, 19 is the antenna gain, 21-1, 21-2 and 21-3 are the control beam pattern 1 and control beam pattern 2 in the X error direction used for pointing error detection. And the control beam pattern 3 is shown.
[0031]
Reference numeral 20-1 denotes a measurement point for detecting a pointing error, and 22-1, 22-2, and 22-3 denote tangents of the respective control beam patterns at the measurement point, which represent a gain change with respect to an error change in the X error direction. Sensor sensitivity 1, 2 and 3. By using three control beams having different sensor sensitivities at the same measurement point 20-1, it is possible to select an optimum one from the three control beams according to the error factor in the pointing direction.
[0032]
Therefore, it is possible to optimize the control by selecting a control beam pattern with high sensor sensitivity for factors with relatively fast fluctuations and selecting a sensor beam pattern with low sensor sensitivity for factors with slow fluctuations but large fluctuation ranges. it can. Further, even when the main cause of error changes with time, it can be dealt with by switching the control beam.
[0033]
FIG. 4 is a diagram showing a third example of the embodiment of the present invention, and corresponds to the invention of claim 3. In the figure, reference numerals 20-2, 20-3, and 20-4 denote measurement points having different distance angles from the beam center, and indicate the directivity directions of the control beams 21-4, 21-5, and 21-6, respectively. This is the position to detect.
[0034]
By installing beacon stations at angles corresponding to the three measurement points and transmitting beacon waves of different frequencies from the respective beacon stations, it is possible to simultaneously detect high-precision pointing direction errors near the measurement points with the three control beams. Therefore, it is possible to obtain a wide detection range with high accuracy.
[0035]
【The invention's effect】
As described above, according to the present invention, the signal from all antenna elements is combined to form a beam in the same way as the communication signal as the directivity control in the phased array antenna, so that the signal-to-noise ratio is increased. It is possible to ensure high-accuracy detection.
[0036]
Then, a configuration is adopted in which a plurality of different excitation distributions are sequentially generated in an additional circuit provided in the variable beam forming circuit, a beacon wave signal is received, a beacon wave arrival direction is identified, and an orthogonal biaxial error signal is detected. Therefore, error detection by arbitrary beam pattern formation is possible, and versatile pointing error detection applicable to various pointing direction control can be realized.
[0037]
In addition, since the directivity control configuration as described above can be combined without changing the configuration of the conventional phased array antenna, it can be easily implemented in response to a demand for higher accuracy. Further, the additional device to be added has the same structure as a communication circuit in terms of hardware, and there is no problem in the additional incorporation due to the design, and the realization is high.
[Brief description of the drawings]
FIG. 1 is a diagram showing a first example of an embodiment of the present invention.
FIG. 2 is a diagram illustrating an example of a pointing error detection method for the direction of a beacon arrival wave of an antenna.
FIG. 3 is a diagram showing a second example of an embodiment of the present invention.
FIG. 4 is a diagram showing a third example of an embodiment of the present invention.
FIG. 5 is a diagram illustrating an example of a configuration of a conventional antenna directivity direction control apparatus.
FIG. 6 is a diagram for explaining a conventional method of detecting a pointing direction error.
[Explanation of symbols]
1-1 Antenna element 1
1-2 Antenna element 2
1-3 Antenna element 3
1-4 Antenna cord 4
1-m Antenna element m
2 Demultiplexer 3 Sensor beam forming circuit 4 Sensor low noise amplifier 4-1 Low noise amplifier 1
4-2 Low noise amplifier 2
4-m Low noise amplifier m
5 Sensor processing circuit 6-1 Communication station 1
6-2 Communication station 2
7 Beacon station 8 Beacon wave 9-1 Communication wave 1
9-2 Communication wave 2
10 Communication signal 10-1 Communication signal 1
11-1 Sensor signal 1
12-1 Pointing error signal X
12-2 Pointing error signal Y
13-1 X error direction 13-2 Y error direction 14 Variable beam forming circuit 15 Additional circuit 16 Excitation distribution output circuit 17-1 Reference beam 1
17-2 Reference beam 2
17-3 Reference beam 3
18-1 Beacon wave gain 1
18-2 Beacon wave gain 2
18-3 Beacon wave gain 3
19 Antenna gain 20-1 Measurement point 1
20-2 Measurement point 2
20-3 Measurement point 3
20-4 Measurement point 4
21-1 Control beam pattern 1
21-2 Control beam pattern 2
21-3 Control beam pattern 3
21-4 Control beam pattern 4
21-5 Control beam pattern 5
21-6 Control beam pattern 6
22-1 Sensor sensitivity 1
22-2 Sensor sensitivity 2
22-3 Sensor sensitivity 3

Claims (4)

A plurality of antenna elements for receiving communication waves and beacon waves from one beacon station ;
A plurality of amplifiers combined one by one with the plurality of antenna elements ;
A variable beam forming circuit connected to the plurality of amplifiers, receiving the communication wave with a beam formed by controlling the amplitude and phase for each path, and outputting a communication signal ;
An additional circuit that is provided in the variable beam forming circuit, synthesizes a beacon wave signal obtained by the plurality of antenna elements and the plurality of amplifiers, and outputs the signal along a predetermined excitation distribution ;
An excitation distribution output circuit that sequentially inputs excitation distributions for forming three or more different beam patterns in the additional circuit ;
The X direction orthogonal to the direction from the reference position of the beacon position where the contour line of the gain of the beam pattern from the additional circuit intersects with the input of the excitation distribution from the excitation distribution output circuit and the angle between the two positions. A sensor processing circuit for outputting a pointing error signal in the biaxial direction of the error direction and the Y error direction ;
A directivity direction control apparatus for a phased array antenna, comprising:   As an excitation distribution for forming different beam patterns, a plurality of beams (array antennas having different sensor sensitivities expressed by a ratio of antenna gain and angle at a measurement point separated from the center of the beam (reference beam) by a certain angle are used. The directivity control apparatus for a phased array antenna according to claim 1, wherein an excitation distribution forming a directivity pattern is input.   As an excitation distribution for forming different beam patterns, an excitation distribution for forming a plurality of beam (array antenna directivity) patterns having the same sensor sensitivity at measurement points at different angles from the center of the beam (reference beam). The directivity control apparatus for a phased array antenna according to claim 1, wherein The additional circuit forms the beam pattern with high sensor sensitivity when the variation in pointing error is fast, and the sensor pattern with low sensor sensitivity when the variation in pointing error is slow and the variation range is large. The directivity control apparatus for a phased array antenna according to claim 2, wherein an excitation distribution for forming a beam pattern is input.

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