JPH10221421A - Orthogonal biaxial control type monopulse tracking circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the size, weight, and cost of an orthogonal biaxial monopulse tracking antenna by constructing the antenna in a planar structure and reducing the number of members by installing two feeding points having opposite phases to each element antenna. SOLUTION: Four element antennas 1-1 to 1-4 are arranged in two lines and two rows and two feeding points of opposite phases are installed to each antenna 1-1 to 1-4. A sum signal is generated by adding the receiving power of the feeding points (for example, 2-7 and 2-8) having the same phase of the antennas (for example, 1-3 and 1-4) belonging to the same line or row to each other. In addition, a difference signal is generated by adding the power of the receiving power of the feeding points (for example, 2-5 and 2-2) having opposite phases of the antenna (for example, 1-1 and 1-2) belonging to the same line or row to each other. Therefore, an orthogonal biaxial monopulse tracking antenna can be reduced in size and weight by constructing the antenna in a planar structure, because no three-dimensional wiring is required and a simple microstrip line can be used for feeding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a quadrature two-axis control type monopulse tracking circuit and an antenna structure suitable for the circuit.

[0002]

2. Description of the Related Art One of the methods of tracking an object to be tracked such as an aircraft, a helicopter, an artificial satellite or the like by a moving object such as a vehicle is to move a pulse signal (guided radio wave) from the object to be tracked. There is a method of variably controlling the attitude or the beam direction of the receiving antenna so that it can be received by the body and the guided radio wave can be more appropriately received. Monopulse tracking is one such method, which generates and uses a sum signal and a difference signal of the received outputs obtained from a plurality of element antennas.

To explain the principle of monopulse tracking, FIG. 2 shows an example of a single-axis control type monopulse tracking circuit. In the figure, reference numerals 201-1 and 201-2 denote element antennas for receiving a guided radio wave from the tracking target 205 at a moving body or the like, and a motor through a belt 208 and a pulley 207. At 209, it is juxtaposed and fixed on a rotary table 206 driven to rotate. The reception output of the element antennas 201-1 and 201-2 is supplied to the rat race 204 via a rotary joint or the like (not shown), and the rat race 204 applies the reception power of the element antenna 201-2 to the reception power of the element antenna 201-1. A sum signal having a power value obtained by adding the received power, and an element antenna 20
A difference signal indicating a power value obtained by subtracting the reception power of the element antenna 201-2 from the reception power of 1-1 is generated using a signal propagation delay on the flattening circuit.

The sum signal and the difference signal respectively represent equivalent beams obtained by combining the beams of the element antennas 201-1 and 201-2, that is, a sum beam and a difference beam (see FIGS. 3 and 4). However, the vertical axis in Fig. 4 is the absolute value of the amplitude). The phase detector 210 detects the phases of the sum signal and the difference signal, and detects the arrival direction of the induced radio wave from the tracking target 205 by comparing the phases. Servo amplifier 211
Is a control member for driving the motor 209 in accordance with the detected direction of arrival, and also has a function of compensating for signal delays in various parts of the circuit and preventing hunting (fluctuation in the angular position of the rotary table 206). I have. Therefore, based on the phase of the sum signal detected by the phase detector 210, the tracking target is initially captured between the left and right maximum gain points of the difference beam, and
The function of performing tracking of the tracking target 205 using a difference beam (difference signal) having a steep directivity in the vicinity of the front direction can be realized by the circuit of FIG.

FIG. 5 shows a circuit configuration obtained by extending the configuration of FIG. 2 to orthogonal two-axis control. In the figure, 301-1 to 301-4 are 2 × 2
Element antennas arranged in rows and columns, 309-1 and 3092 are motors for rotating the element antenna group around the elevation and azimuth axes, respectively, 304 is a rat race, 310-1 and 310
-2 is a phase detector corresponding to the X-axis ("row" of the element antenna arrangement) and Y-axis (also "column"), and 311-1 and 311-2 are servo amplifiers corresponding to the X-axis and Y-axis, respectively. It is. The functions of these members are the same as those of the members having the same names in FIG. However, servo amplifier 311-1 and
311-2 also performs conversion from the (X, Y) coordinate system to the (azimuth, elevation) coordinate system. According to such a configuration, since a sum signal and a difference signal are obtained for each of the two orthogonal axes of X and Y, the tracking target can be tracked by the element antenna group for each of the azimuth and the elevation angle.

It is also conceivable to realize the circuit shown in FIG. 5 with a planarized element antenna. However, in practice, even though the element antenna itself can be planarized, the entire antenna structure cannot be planarized.

For example, as shown in FIG. 6, a 2 × 2 matrix of planarized element antennas 101-1 to 101-4 is arranged, and a rat race 104-1 is arranged on the X axis and a rat race is arranged on the Y axis. Assume that 104-2 is provided. In this case, for example, in order to generate a sum signal and a difference signal on the X axis, the received powers of the element antennas 101-1 and 101-2 belonging to the upper row in the figure are combined in phase while the lower row in the figure is combined. Element antenna belonging
The received powers of 101-3 and 101-4 are in-phase synthesized, and these two types of in-phase synthesized results are combined in the rat race 104-1. Signals are output from the in-phase combined output terminal and out-of-phase combined output terminal of the rat race 104-1. Must be realized. The output from the in-phase coupled output terminal of the rat race 104-1 is the above-described sum signal on the X-axis, and the output from the anti-phase coupled output terminal is the difference signal. Accordingly, in order to obtain the sum signal and the difference signal on the X axis, in addition to the rat race 104-1, a power combiner 103-7 for synthesizing the received power of the element antennas 101-1 and 101-2 in phase, and an element antenna 101- A power combiner 103-8 for in-phase combining the received powers of 3 and 101-4 is required. To generate the sum signal and the difference signal for the Y axis, similarly, in addition to the rat race 104-2, the element antennas 101-1 and 101-3
And a power combiner 103-6 that performs in-phase synthesis of the received powers of the element antennas 101-2 and 101-4. In addition, for example, it is necessary to distribute the reception output of the element antenna 101-1 to the power combiners 103-7 and 103-5.
It is necessary to provide 103-4 in association with each of the element antennas 101-1 to 101-4.

As described above, in order to realize an antenna structure having a large number of members, that is, a total of eight power combiners and distributors in addition to two rat races, three-dimensional wiring for connecting the respective members is required. What is inevitable will be obvious from the description of FIG. Therefore, according to the conventional technique, planarization of the antenna structure cannot be achieved, and advantages such as reduction in size and weight due to planarization of the element antenna cannot be sufficiently exhibited. In addition, the large number of members constituting the antenna structure itself is an obstacle to reducing the size, weight, and cost.

[0009]

SUMMARY OF THE INVENTION One of the objects of the present invention is to make an antenna structure suitable for a quadrature two-axis control type monopulse tracking circuit flattenable, and to realize a further reduction in size and weight. Another object of the present invention is to reduce the number of members constituting an antenna structure, and realize a reduction in size, weight, and cost. In the present invention, these objects are achieved by modifying the method of feeding power to each element antenna.

An antenna structure according to a preferred embodiment of the present invention includes four element antennas arranged in a 2 × 2 matrix and a feeder circuit related to the reception output of these element antennas. This feeding circuit is the first of the four element antennas.
The X-axis sum signal is generated by performing in-phase synthesis on the reception outputs of the element antennas belonging to the row, and the X-axis difference signal is generated by performing the anti-phase synthesis on the reception outputs of the element antennas belonging to the second row. A Y-axis sum signal is generated by combining the received outputs of the element antennas belonging to the first column in phase, and a Y-axis difference signal is generated by combining the received outputs of the element antennas belonging to the second column in reverse phase. . In this embodiment, further, a sum beam forming power combiner that performs in-phase combining by power addition of the reception output from the feed point whose current phase is the same, and a feed point whose current phase differs by 180 ° from each other And a power divider for difference beam forming that performs antiphase combining by power addition of the received outputs of the X and Y axes in the power supply circuit.

As described above, by using not only the in-phase synthesis but also the anti-phase synthesis with respect to the reception output of the element antenna, the rat race which is a member that outputs two types of inputs by in-phase coupling and anti-phase coupling. Becomes unnecessary. Also,
The above-mentioned in-phase synthesis and anti-phase synthesis can be realized by simple means such as anti-phase two-point feeding for each element antenna. This also makes it possible to simplify the wiring of the wiring between the members on the antenna structure, so that the element antenna, the sum beam forming power combiner and the difference beam forming power combiner are located on the same plane. It is also possible to route the plane wiring between them. Then, by controlling the attitude or the beam direction of the antenna based on the antenna having such a structure and the sum signal and the difference signal obtained for each of the X axis and the Y axis from the antenna, the antenna can control the distance from the target to be tracked. By providing a control circuit for tracking a signal, the orthogonal 2 can be reduced in size and weight and price compared to the conventional one.
An axis-controlled monopulse tracking circuit is obtained.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, in the antenna structure according to the preferred embodiment of the present invention, four element antennas 1-1 to 1-4 are arranged in a 2 × 2 matrix, and each of the element antennas 1-1 to 1-1 is arranged. Each of 1-4 has two feeding points. The current phase at one feed point (for example, 2-1) on the same element antenna (for example, 1-1) is shifted by 180 ° with respect to the current phase at the other feed point (for example, 2-5). One of the features of the present embodiment is that two feed points are provided for each of the element antennas 1-1 to 1-4 as described above. I have set a point. Another feature of the present embodiment is that in-phase feeding points (for example, 2-7 and 2-7) of element antennas (for example, 1-3 and 1-4) belonging to the same row or column.
-8) The sum signal is obtained by adding power to the received output of
In addition, element antennas belonging to the same row or column (for example, 1-1
The above two feed points are used to generate a difference signal by power addition of the received outputs of the feed points (eg, 2-5 and 2-2) having opposite phases of 1-2). Is to be. Therefore, in the antenna structure according to the present embodiment, a rat race is not required, and only four power combiners 3-1 to 3-4 are required in total in the X-axis and the Y-axis. Weight reduction and cost reduction are realized, and three-dimensional wiring is not required, and power can be supplied using a simple microstrip line. A detailed description of the quadrature two-axis control type monopulse tracking circuit using this antenna structure together with the phase detector, servo amplifier, motor, and the like shown in FIG. 5 is omitted, but unclear points arise for those skilled in the art. Will not.

[Brief description of the drawings]

FIG. 1 is a wiring diagram illustrating an antenna structure according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration of a single-axis control type monopulse tracking circuit.

FIG. 3 is a diagram showing directivity of a sum beam and a difference beam.

FIG. 4 is a diagram showing directivity of a sum beam and a difference beam.

FIG. 5 is a diagram illustrating a configuration of a quadrature two-axis control type monopulse tracking circuit.

FIG. 6 is a wiring diagram illustrating an example of a conventional antenna structure.

[Explanation of symbols]

1-1 to 1-4 element antenna, 2-1 to 2-8 feeding point, 3-1
33-4 Power combiner.

Claims (3)

[Claims] An X-axis sum signal is generated by performing in-phase synthesis of four element antennas arranged in a 2 × 2 matrix and reception outputs of the element antennas belonging to a first row.
, An X-axis difference signal is generated by combining the reception outputs of the element antennas belonging to the first row and the Y-axis sum signal by combining the reception outputs of the element antennas belonging to the first column in phase. A feed circuit that generates a Y-axis difference signal by combining the reception outputs of the element antennas belonging to the second column in antiphase, wherein the feed circuit receives signals from feed points having the same current phase. A sum beam forming power combiner that performs the above-described in-phase combining by adding power to the output,
0 ゜ An antenna structure, characterized in that it has a power divider for difference beam formation that performs the above-described inverse-phase combining by power addition of reception outputs from different feeding points, for each of the X-axis and the Y-axis. 2. The antenna structure according to claim 1, wherein
An antenna structure, wherein planar wiring is routed between the element antenna, the sum beam forming power combiner, and the difference beam forming power combiner so that they are located on the same plane. 3. An antenna having the structure according to claim 1 or 2, and a posture or beam direction of the antenna is controlled based on a sum signal and a difference signal obtained from the antenna for each of an X axis and a Y axis. A control circuit for tracking a signal from a tracking target by the antenna, and a quadrature two-axis control type monopulse tracking circuit.