JPH0823576B2 - Wireless direction finding antenna device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention has a structure in which antennas arranged to obtain a phase difference output between a pair of antenna elements arranged at intervals are arranged at intervals on a circular ring, and the positions of the antennas are arranged. The present invention relates to a radio direction detecting antenna device for detecting the arrival direction of a radio wave by using the phase of the amplitude change of a signal extracted by switching the phase difference output as an azimuth component.

[Prior art]

Such an antenna device has a span error determined by the relationship between the distance between the antenna element pair and the wavelength of the radio wave,
The fact that the distance between the pair of antenna elements cannot be increased with respect to the wavelength is taught, for example, in "Radio Direction Measuring Machine" (Ito and Goto, Corona, pages 37-38). Further, the above-mentioned document (pages 180 to 182) teaches that the site error caused by the influence of the disturbing object on the antenna device becomes smaller as the size of the arrangement outer diameter increases.

For this reason, there is proposed a method of avoiding the above span error and site error by arranging antenna elements at intervals along a circumferential ring line, as in Japanese Patent Laid-Open No. 60-80780, "Azimuth Measuring Antenna Device".

[Problems to be solved by the invention]

There is a problem in that the means for performing the sense setting for the output of each antenna element pair must be provided only with the above-mentioned means for arranging the antenna element pairs on the circumferential ring line at intervals.

[Means for solving problems]

This invention delays the output of one of the pair of antenna elements of each antenna to obtain a phase difference output from the output of the other and thereby has unidirectional directivity to eliminate the need for sense determination. It is designed to solve problems.

[Work]

When the delayed antenna element of the output of the antenna element pair is located in front of the arrival direction of the radio wave, the interval between the antenna element pair is apparently narrowed by the delayed amount. Therefore, the phase difference output between the antenna element pair with respect to the radio wave becomes small. On the other hand, when the delayed antenna element is located rearward with respect to the arrival direction of the radio wave, the interval between the antenna elements is widened accordingly, and the phase difference output increases. The output of each antenna exhibits unidirectional directivity with respect to the arrival direction of the radio wave.

Therefore, the arrangement direction of each antenna element pair is made different, and the output obtained by switching the output of each antenna also shows the change of the output having the unidirectional directivity.

In addition, since the output of each antenna exhibits unidirectional directivity, it is possible to remove the restriction on the outer diameter of the antenna and increase the outer diameter of the antenna, which can reduce the site error.

〔Example〕

 An embodiment will be described below with reference to the drawings.

In the figure antennas A1, A2, A3, A4, A5, A6, A7, A8
Are antenna elements 1a and 1b, 2a and 2b, 3a and 3b, 4a and 4b,
It is an antenna in which 5a and 5b, 6a and 6b, 7a and 7b, and 8a and 8b are spaced apart as an antenna element pair, and are, for example, an adcock antenna or a loop antenna.

The antennas A1 to A8 are arranged on the circumferential annular line 20, for example, on the circumferential line with different directional angles of each antenna element pair, that is, with different directional angles of lines connecting the antenna elements of each antenna element pair. It was done.

Each of the antennas A1 to A8 has a delay circuit 1d, 2d, 3d, for delaying one output of the antenna element pair as described later.
4d, 5d, 6d, 7d, 8d are provided, and the phase difference output between the delayed output and the other output is the antenna output signal 1c, 2c, 3c,
Output as 4c / 5c / 6c / 7c / 8c. Each antenna A1 to A8
Looking at one of the antennas A1, as shown in FIG. 2, the antenna elements 1a and 1b are arranged at an interval l (preferably an interval at which the above span error is small), and one antenna element 1b
Is provided with a delay circuit 1d for delaying the interval l by the same time as the time T of propagation of the radio wave, for example, a delay cable, and the phase difference output between this delay output and the output of the other antenna element 1a is output. The output extracted by the differential transformation circuit 1e is output as an antenna output signal 1c, and the other antennas A2 to A8 are also configured in the same manner.

Each antenna output signal 1c is differentially transformed when the electric field e ₀ of the incoming radio wave at the midpoint p of each antenna element is e ₀ = E ₀ e ^jwt , and the incoming direction of the radio wave with respect to the antenna element pair line 1f is θ and the wavelength is included. The inputs e ₁ and e ₂ of the circuit 1e are as follows.

Therefore, if the gain of the differential transformation circuit 1e is 1, the antenna output 1c is given by the following equation.

Then, the sin term in equation (3) is Is almost equal to (Cos θ + 1) in the equation (4) indicates the directional characteristic of the antenna, and has the ideal gardioid type unidirectional directional characteristic as shown in FIG. 3-1.

The other antennas A2 to A8 are similarly configured, and the antenna element pair lines 2f, 3f, 4f, 5f, 6f, and
Since 7f and 8f are arranged in different directions with respect to the arrival direction of the radio waves, each antenna output signal 1c to 8c is
The output in each corresponding direction of the directional characteristic of FIG. 1 is obtained.

Although l / λ << 1 is set in the above description, as l / λ increases and approaches 0.5, the directional characteristics deviate from the ideal cardioid type as shown in FIG. 3-2. Although an error occurs, this azimuth error can be reduced by increasing the number of antenna element pairs.

When the antenna element pair pairs 1f to 8f of the antennas A1 to A8 in FIG. 1 are arranged at different angles of 45 degrees on the circumference line as shown in the figure, and the arrival direction of radio waves is 45 degrees. The magnitudes of the output signals 1c to 8c correspond to the directions shown in FIG. 3-1.

In FIG. 1, the switching circuit 11 controls each antenna output signal 1c ...
Outputs obtained by switching connection of 8c are output as a switching detection signal 11a in a predetermined order (1c, 2c, ..., 8c in the figure) by a switching signal 12a described later.

The switching wave circuit 12 is a signal for switching and connecting the antenna output signals 1c to 8c and is a time series in the rectangular wave signal group according to the above definition (in the case of the figure, a pulse train sequentially following as in FIG. 4a). Is output as the switching signal 12a.

The switching detection signal 11a can be amplified and detected by the reception amplification circuit 13 and the AM detection circuit 14 to obtain the detection signal 14a (output signal of the detection circuit 14) of FIG. This detection signal 14a is
As shown in FIG. 4, the basic waveform of the amplitude change, that is, the fundamental wave component changes sinusoidally, and the phase of this fundamental wave component becomes the azimuth component.

The detection signal 14a has a size in each direction shown by 1c to 8c in FIG. 3-1 arranged according to the switching signal 12a.

The adjusting circuit 15 changes the time point of the time-series signal from the switching wave circuit 12 to a switching detection signal by the reception amplification circuit 13 or the like so that the sampling timing described later is accurately performed.
The delay time until the detection signal 14a is obtained from 11a is adjusted, and the sampling pulse signal is given to the sampling circuit 16.

The sampling circuit 16 samples and outputs the analog value of the amplitude of the detection signal 14a at an appropriate time point near the middle of each of the above switching times, outputs the analog value, and converts it into a digital value by the A / D conversion circuit 17 and a processing circuit 18 described later. To the azimuth component data signal 17a.

The reference circuit 21 detects a signal time point at which the time-series signal corresponding to the reference direction s in the switching signal 12a of the switching wave circuit 12 is delay-adjusted by the adjustment circuit 15 and supplies it to the processing circuit 18 as a reference time point data signal 21a.

The processing circuit 18 uses the azimuth component data signal 17a as a sampling value of the fundamental wave component of the signal waveform, that is, the azimuth component shown in the detection signal 14a of FIG. 93363 "Radio azimuth measurement method", etc. are Fourier expanded to calculate the phase point of the fundamental wave component and output as azimuth value signal 18a, and display circuit 1
Display in 9.

The calculation of this phase point is performed using the reference time point signal 21a as a reference point.

In other words, for the sine wave or cos wave waveform signal starting from the reference time point data signal 21a, the azimuth component data signal 1
The phase delay value of the sine wave or cos wave signal obtained by 7a is calculated as the azimuth value.

[Modified Example]

 This invention can be modified as follows.

(1) The delay circuits 1d to 8d have the same amount of delay as the time corresponding to the interval l in order to obtain an ideal cardioid type directional characteristic. The error due to the lobe is remedied by increasing the number of antenna devices or performing an appropriate correction process in the processing circuit 18.

(2) In accordance with the topography of the installation location, for example, the peripheral annular line 20 is changed to an elliptical or other deformed annular line as shown in FIG. 5, or
Arrangement intervals and angles of the respective antennas are made unequal, and the time series of the switching signal 12a and the calculation of the azimuth component data signal in the processing circuit 18 are performed in accordance with these modified arrangements.

(3) The number of the antennas A1 to A8 to be arranged may be three or more, an appropriate number, and other circuit parts are modified according to the number.

(4) The switching order of the antenna output signals 1c to 8c is appropriately changed to form an irregular or regular order such as 1c → 6c → 2c → 3c → 5c → 4c → 7c → 8c, and the processing circuit 18 The process of replacing the azimuth component data signal 17a in step 1) with the data in the regular order from the regular or irregular change order is performed.

(5) The antenna element pair lines 1f to 8f of the antennas A1 to A8 are
As shown in FIG. 6, they are arranged on the tangential line or the chordal line of the circumferential annular line 20.

In this case, the signal waveform of the detection signal 14a is the same as that obtained by shifting the detection direction θ by 90 ° with respect to 14a in FIG.

(6) The sides of the respective antennas A1 to 8A into which the delay circuits 1e to 8e are inserted are appropriately made different, and the processing in the processing circuit 18 is corrected in the same manner as in the above item (4).

〔The invention's effect〕

According to the present invention, a unidirectional directional antenna having a delay circuit in one of each antenna pair is arranged on the circumferential annular line at different angles, and the output of these antennas is switched by a simple means to arrange the outer diameter. And the site error can be reduced to provide a radio direction detecting antenna device that does not require sense determining means.

[Brief description of drawings]

The drawings show embodiments, and FIG. 1 is a block diagram of the apparatus.
FIG. 2 is a circuit configuration diagram of each antenna, FIG. 3-1 and FIG.
Fig. 2 shows the antenna directional pattern, Fig. 4 shows the signal waveform of the main part,
5 and 6 are plan views showing the arrangement of the antennas. A1 to A8 …… Antenna, 11 …… Switching circuit, 12 …… Switching circuit, 13 …… Reception amplifier circuit, 14 …… AM detection circuit, 15 …… Adjusting circuit, 16 …… Sampling circuit, 17 …… A / D conversion circuit 18 …… Processing circuit, 19 …… Display circuit 21 …… Reference circuit.

Claims (1)

[Claims] 1. An antenna element pair arranged at intervals is used as one antenna, and a plurality of said antenna elements each having a different direction angle of each antenna element pair are arranged at intervals on a circular loop line, and each antenna is switched to obtain. A radio direction detecting antenna device for detecting a direction of arrival of a radio wave by an azimuth component in a detection signal, comprising: a. Delaying the output of one antenna element of each antenna element pair and then outputting the other antenna element. Delayed phase difference signal means for obtaining a unidirectional directional signal by obtaining a phase difference, b. Based on each unidirectional directional signal obtained by the switching, the fundamental wave component of the amplitude change becomes a sine wave shape. And a detection signal means that obtains the detection signal having the phase of the fundamental wave component as the azimuth component while changing, thereby eliminating the restriction on the layout of the antenna device. However, the wireless direction finding device is characterized in that the layout outline is enlarged to reduce the site error and the sense determination is unnecessary.