JPS6382002A - Antenna system for radio direction finding - Google Patents

Abstract

PURPOSE:To obtain an antenna system which has a small site error even to a radio wave short wavelength like an ultrasonic wave by arranging plate type antennas which are axially symmetric about respective parabolas on >=3 parabolas in a detection plane. CONSTITUTION:Antennas 11 - 14 are plate type antennas provided on parabolas (a), (b), (c) and (d) at 90 deg. intervals, and constituted by arranging conductor plates which are axially symmetric about the respective parabolas, e.g. square aluminum plates so that their diagonals coincide with the parabolas. Consequent ly, directivity characteristics of the antennas 11 - 14 are cardiod type unidirectivity shown in a figure (a). When the respective directivity characteris tics of the antennas 11 - 14 are represented together in one plane, directivity characteristics 11A - 14A shown in a figure (b) are obtained and four-phase rectangular signals which shift in phase in order are used as switching signals to allow the antenna 1 whose radio wave arrival direction is alpha to generate the maximum output 11, thereby performing direction finding.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an antenna device for radio direction finding that detects the arrival direction of radio waves using a plurality of plate antennas.

[Prior art]

A method of detecting the direction of arrival of radio waves using the azimuth component in the output obtained by a plate antenna having a plane parallel to the plane on which the direction of arrival of the radio waves to be detected is arranged is disclosed in Japanese Patent Laid-Open No. 60-14766, It is disclosed in 1988-10'8404 and the like. These are implemented by means of alternately switching each vertex of two rectangular plates between signal extraction and termination, or by means of stacking a plurality of rectangular plates one above the other and performing similar switching.

[Problem that the invention seeks to solve]

In general, among the measurement errors in radio direction finding K, the zero sight error due to the influence of disturbance objects in the pond is:
The larger the outer diameter of the antenna arrangement, the less it will be. However, with the conventional antennas mentioned above, when a groove is formed for use in the ultra-high frequency band, it cannot be spread beyond the wavelength of the detection radio wave, so there is a limit to reducing this site error. There was a problem that there was.

[Means for solving problems]

This invention makes it possible to increase the outer diameter of the antenna arrangement and reduce errors by arranging three or more plate antennas at intervals on a radial line.

[For production]

Each antenna is formed as an antenna with a unidirectional directional characteristic whose directional direction is the radial line direction in which it is arranged, and each antenna is switched so that the maximum or minimum sensitivity direction determined by the change in the output size is determined by the direction of the arrival of radio waves. Detect as a direction.

〔Example〕

An embodiment of a direction finding antenna device of 250 MHz to 500 MHz will be described with reference to the drawings.

In the figure, antennas 11 to 14 are plate-shaped antennas installed on radial lines a, b, c, and d at 90° intervals, and are made of a conductive plate having a line-symmetric shape with respect to each radial line, such as a rectangular aluminum conductor plate. The plates are arranged so that their diagonal line coincides with the radial foreshadowing line.

The terminating resistors 21 to 24 are resistors corresponding to the terminating impedance described later, and are located at the inner apex point of each antenna 11 to 14,
That is, the core wire side of the receiving side of the coaxial cable connector is used as a terminal at the termination points 25 to 28, for example as shown in FIG.
A non-inductive resistor is connected between the frame-side core wire and the shield side of the connector, that is, a coaxial non-reflection terminator, which is electrically connected to a grounding board 10 (described later).

The signal extraction terminals 61 to 64 are terminals provided at the outer apex points of each antenna 11 to 14, that is, at the extraction points, and for example, the receiving side of a coaxial cable connector is used as the terminal, as shown in FIG. As shown in (a), the core side is connected to the extraction point, the shield side is connected to a grounding board 1O (described later), and coaxial cables 101 to 104 are connected to the frame side.

The signal outputs of the signal extraction terminals 61 to 64 are connected to respective switching circuits 41 to 41 to be described later by signal extraction cables 101 to 104.
Guided by 44.

The grounding board 10 connects each antenna 11 to 14 with respect to incoming radio waves.
A conductor plate that is considered to be electrically grounded when viewed from above, for example, 2~
It is an aluminum plate with an outer diameter about 3 times the size, and is supported on the ground or in the air by an appropriate method. Height h at which each antenna 11 to 14 is supported on the ground board 10
The relationship between γ and the value γ of the terminating resistors 21 to 24 is determined by adjusting the height h so that the value γ of the impedance terminating resistor at the terminating point of the wave impedance between each antenna 11 to 14 and the grounding board IO becomes the value γ. For example, each antenna 11
Each piece of ~14 is 12 cm, the distance S between the antennas is 5 cm, the value γ of the terminating resistors 21 to 24 is 50 ohms, and the signal extraction cables 101 to 104
If the impedance of is 50 ohms, the height h is 2 to 3
The heights of the signal extraction terminals 61 to 64 and the terminal points 25 to 28 are set to be centimeters.

In this case, the outer diameter of the antenna arrangement is about 41 cm, and the outer diameter of the grounding board 10 is about 100 cm.

The switching unit 5 is a shield box body that houses switching circuits 41 to 44 described later and a switching signal generation circuit 9 that generates switching signals 9A to 9D, etc., and is a cabinet made of an aluminum plate, for example, and is a cabinet made of an aluminum plate. antennas 11-14
and fix it on the opposite side.

The switching circuits 41 to 44 each include a diode 7 and a resistor 8 provided individually, and a choke coil 11 provided in common.
0, and by applying switching signals 9A to 9D given from a switching signal generation circuit 9 to be described later between each resistor 8 and a choke coil 110, the input of each diode 7 is controlled by cables 101 to 104. Each antenna 11-1 given on the side
4 received outputs in a defined order, for example, antenna 1
1, 12, 13, and 14 are repeated in the order of 1, 12, 13, and 14 to sequentially switch and take out the signals and output them to the common output line 111 to obtain the detection signal 111A.

In the above configuration, the directivity characteristics of each of the antennas 11 to 14 become a cardioid type unidirectional directivity as shown in FIG. 4(a). Therefore, if the directional characteristics of the antennas 11 to 14 are expressed all at once, the directional characteristics are 11A-14A as shown in FIG. 4(b), and the switching signals 9A to 9D are sequentially expressed as shown in FIG. 4(C). By using four-phase rectangular wave signals with shifted phases, the antenna 11 whose arrival direction of the radio wave is α, such as the detection signal 111A in the figure, has the maximum output 11a, and the antenna 13 in the opposite direction has the minimum output. Detection signal 1 with an azimuth component such as output 13a
11A can be obtained, and direction detection can be performed by, for example, performing Fourier expansion on the signal shown in FIG. 4(C) and detecting the direction based on the phase point of the fundamental wave.

[Modification example]

This invention can be implemented in the following modifications.

(1) The number of antennas 11 to 14 should be three at the minimum as shown in FIG. 5, and it is better to provide as many antennas as possible in order to improve the arrangement outer diameter effect, detection sensitivity, direction accuracy, etc.

(2) Radial line a in the direction in which the antennas 11 to 14 are arranged
- If the angular intervals between b and c cannot be made equal due to the structure of the device, appropriate unequal angular intervals are set and the angle calculation for direction finding is made accordingly.

(3) If the positions of the antennas 11 to 14 on the radial line, that is, the distances from the center of the antenna arrangement, cannot be made equal due to structural reasons, they are made uneven as shown in Figure 6 to calculate the angle for direction finding. to correspond to this.

(4) The shape of the plate of the antennas 11 to 14 should be circular, rhombic, even polygonal, etc., symmetrical to each radial line of each antenna 11 to 14, and also symmetrical to a line perpendicular to the radial line. shape, and each apex angle or edge of the circular arc is used as a signal extraction point and a terminal point.

In addition, if the frequency band of the radio waves to be detected can be narrowed, it is possible to create a shape that is symmetrical only with respect to each radial line and asymmetrical with respect to the line orthogonal to each radial line, for example, as shown in Figure 8 (a). You can.

(5) Supports 31 to 34 made of high frequency insulating material for supporting each antenna 11 to 14 are provided as shown in FIG. 8(b).

Also, if the impedance on the signal extraction point side, that is, the impedance of the signal extraction cable, and the impedance on the termination point side, that is, the value γ of the terminating resistor, are different, or
If the shape of the antenna is different on the inside and outside, change the height hl on the signal extraction point side of each antenna 11 to 14 and the height h2 on the termination point side as shown in Figure 8(b) for matching. do.

(6) Connect the terminating resistors 21 to 24 between the terminating points 25 to 28 of each antenna 11 to 14 and the ground substrate IO as shown in FIG.

[Effects of the Invention] As described above, according to the present invention, by arranging the plate antennas at intervals, the outer diameter of the antenna arrangement can be increased. The present invention has the advantage of being able to provide a radio direction finding antenna device with little site error. In the above example, the case of 250 MI (Z ~ 500 MH2) was described, but 150 MH 7 ~ 500! Even with IIH2, the minimum signal-to-noise ratio and front-to-back ratio of directional characteristics can be obtained as a direction finder.

In addition, each side of each antenna 11 to 14 is approximately 25 cm, and the spacing between the antennas is approximately 10 cm.
It is possible to obtain an antenna device tailored to the desired frequency band, such as an antenna device for 0 MHz to 20 OMHz.

A detection signal similar to the above can be obtained even with a configuration in which the signal extraction points 61 to 64 and the termination points 25 to 28 of each antenna 11 to 14 are reversed, but the directivity of each antenna 11 to 14 is formed. Since other antennas are arranged in the same direction, the directivity characteristics are disturbed due to the influence of these antennas, making it unsuitable as a direction finding antenna device.

[Brief explanation of the drawing]

Figure 1 is a plan view, Figure 2 is a longitudinal sectional view, Figure 3 is a circuit configuration diagram, Figures 4 (a) and (b) are directivity pattern diagrams, Figure 4 (
c) is a signal waveform diagram of each part, Figures 5 and 6 are a plan view of the antenna arrangement, Figure 7 is a side view of the main parts, Figure 8 (a) is a plan view of the antenna shape, and Figures 8 (b) and 6. FIG. 9 is a sectional view of the main part. 11-14・Antenna, 21-24・Terminal resistor 25-2
8. Termination point, 31-34. Strut. 41-44・Switching circuit 8 5・Switching device. 8.Resistor, 9.Switching signal generation circuit. 10・Grounding board, 110・Choke coil. 111・Output line, 101-104・Signal extraction cable. 11A to 14A・Antenna directional characteristics. 11a to 14a・Output of each antenna. 9A to 9D・Switching signal, h, hl, h2・Height of antenna from ground board. a-d, radial line, D, outer diameter of arrangement. S: Antenna spacing, α: Arrival direction of radio waves. 08~θ, angular interval of radial lines. 7. 41 Beqha C (C) Cα) Engraving of Cb's drawing (no change in content) r(1) (b) 'Kiqm 2IN24 Procedural amendment (method) % formula % 1, of the case Indication Patent Application No. 61-227778 2. Name of the invention: Antenna device for radio direction finding 3. Relationship with the amended case: Patent applicant: 2-10-45 Kamiosaki, Tokyo Parts Industry Ward, 141 Showa 6
November 25, 1 (Delivery date) 5. Full text of the specification to be amended/Drawings 6. Contents of the amendment (1) Specification The engraving of the specification originally attached to Book M/As shown in the attached sheet (in (2) Drawings Figure 8 is amended as shown in the attached red inscription. 7. List of attached documents (1) Specification for amendment 1 copy (2) Drawings for amendment 1 copy Procedural amendment (voluntary) October 1988 3rd day of the month

Claims (1)

[Claims] A ground plane placed in a detection plane that includes all directions to be detected, and a plurality of plate antennas parallel to the ground plane. A terminal resistor is connected to one end of each of the plate antennas parallel to the ground plane, and the other end is used for signal extraction. An antenna device for radio direction finding that detects the direction of arrival of radio waves using a change in the magnitude of a signal in a detection signal obtained by switching the received signals of each antenna as a point in a predetermined order as an azimuth component, comprising: a , antenna arrangement means for arranging the plate antenna having a shape symmetrical with respect to each radial line on three or more radial lines in the detection plane; b. connecting each inner end of the plate antenna to the terminal end; and signal extraction means for obtaining the detection signal by using each outer end as the signal extraction point, thereby increasing the outer diameter of the antenna arrangement and reducing site errors. antenna device.