JPH0868841A - Radio wave incoming direction detector - Google Patents

Abstract

PURPOSE: To detecting the incoming direction of a radio wave having narrow pulse width. CONSTITUTION: Delay lines 8a-8f having delays, corresponding at least to the switching time difference of a switch 6, is inserted between the output terminals of directive antennas 7a-7f and the corresponding input terminals of the switch 6, respectively. The timing selected at each switching input terminal of the switch 6 and the receiving time of incoming signal are then adjusted. Consequently, even when the pulse width of radio wave is too narrow to be neglected as compared with the switching time of the switch 6, the switch 6 can switch the signal received by any directive antenna surely without causing extinction thereof and can deliver the signal to a pulse amplitude detector 5. Consequently, the incoming direction of radio wave having narrow pulse width can be detected accurately.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio wave arrival direction detecting device for detecting the direction of arrival of a pulse modulated wave emitted from a radar or the like.

[0002]

2. Description of the Related Art As a radio wave arrival direction detecting device for detecting the direction of arrival of a pulse modulated wave emitted from a radar or the like, a conventional radio wave arrival direction detection apparatus has been proposed.
For example, the one shown in FIG. 3 is known. In FIG.
This radio wave arrival direction detecting device includes an omnidirectional antenna 1, a signal detector 2, a receiver 3, a signal processor 4, a pulse amplitude detector 5, a switch 6, and a plurality of directional antennas (7
a to 7f) are basically provided.

The omnidirectional antenna 1 has an omnidirectional characteristic in a horizontal plane, for example, and outputs to the signal detector 2 received signals of radio waves coming from all directions in the horizontal plane. On the other hand, the plurality of directional antennas (7a to 7f) are arranged in, for example, an arc shape at predetermined angular intervals (equal intervals or unequal intervals) and are directed from, for example, a specific azimuth range in a horizontal plane, and come from a specific azimuth The received signal of the radio wave is output to the switch 6.

The signal detector 2 outputs a trigger signal to the switch 6 when detecting a received signal related to the pulse modulated wave from the received signals input from the omnidirectional antenna 1, and outputs the detected received signal. Give to the receiver 3.

[0005] The receiver 3 detects the frequency, pulse width, and the like of the input received signal and supplies the detected signal to the signal processor 4.

On the other hand, the switch 6 is a multi-input, one-output switch using a PIN diode, and a reception signal of a corresponding one of a plurality of directional antennas (7a to 7f) is applied to each of the switching input terminals S1 to S6. When the trigger signal is input, the switching input terminals S1 to S6 are sequentially selected at predetermined time intervals, and the received signals are sequentially applied to the pulse amplitude detector 5.

[0007] The pulse amplitude detector 5 detects the amplitude of the pulse modulated wave received by the plurality of directional antennas (7 a to 7 f), and supplies the amplitude to the signal processor 4.

In the signal processor 4, the input amplitude values are compared, the directional azimuth of the directional antenna that gives the maximum value is detected as the arrival direction of the radio wave, and the azimuth data is obtained from the frequency and pulse width of the receiver 3. Along with it, it is recorded as radio wave specifications.

[0009]

In the conventional radio wave arrival direction detecting device, when a radio wave with a narrow pulse width arrives,
There is a problem that it may be difficult to calculate the azimuth accurately. That is, in FIG. 3, the arrival direction of the radio wave is 7
It is determined by comparing the amplitudes of the received signals of all the directional antennas a to 7f, but the switch 6 selects each switching input terminal from S1 to S6 at constant time intervals. Then, for example, when the pulse width of the incoming radio wave is t, the time for switching from the switching input terminals S1 to S4 of the switch 6 is T, and the relationship between them is T> t, the directional antennas of 7e and 7f are The reception signal of No. 2 ends while the switch 6 switches from the switching input terminals S1 to S4, is not transmitted to the pulse amplitude detector 5, and does not serve as a reference for azimuth determination.

An object of the present invention is to provide a radio wave arrival direction detecting device which can accurately detect the radio wave arrival direction even when the pulse width of the radio wave is so small that the switching time of the switch cannot be ignored.

[0011]

Means for Solving the Problems In order to achieve the above object, a radio wave arrival direction detecting device of the present invention has the following configuration. That is, the radio wave direction-of-arrival detection device of the present invention includes: a non-directional antenna for detecting an incoming radio wave; a plurality of directional antennas for detecting the direction of an incoming radio wave; A switch for switching and outputting a plurality of directional antenna reception signals in a predetermined order in response;
A delay line having at least a delay amount corresponding to a switch switching time difference is inserted between each output end of the plurality of directional antennas and a corresponding input end of the switch; It is characterized by the following.

Here, the omnidirectional aerial may have an omnidirectional characteristic in a horizontal plane, or may have a spherical omnidirectional characteristic. Further, the plurality of directional antennas are arranged at a predetermined angular interval so as to direct in a specific azimuth range or an omnidirectional range in a horizontal plane, and further to direct in an omnidirectional range of a spherical surface. Since the arriving radio wave is a weak signal, the delay line is composed of an optical fiber type delay line or a superconducting type delay line with little loss. It should be noted that the plurality of directional antennas that are set by directing in a specific azimuth range in the horizontal plane may be able to be configured by a multi-beam antenna having a plurality of power feeding units.

[0013]

Next, the operation of the radio wave arrival direction detecting apparatus of the present invention configured as described above will be described. According to the present invention, a delay line having at least a delay amount corresponding to a switching time difference between switches is inserted between each output terminal of the plurality of directional antennas and a corresponding input terminal of the switch, and each switching input terminal of the switch is The timing at which the signal is selected and the timing at which the received signal reaches each switching input terminal are adjusted.

Therefore, even if the pulse width of the radio wave is not negligible with respect to the switching time of the switch, the switch can reliably switch and output the received signals of all the directional antennas without extinction. Even when a narrow radio wave arrives, the direction of arrival of the radio wave can be accurately detected.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. The same components as those in the related art (FIG. 3) are denoted by the same reference numerals, and description thereof will be omitted. FIG. 1 shows a radio wave arrival direction detecting apparatus according to a first embodiment of the present invention. In FIG. 1, an omnidirectional antenna 1 has omnidirectional characteristics in a horizontal plane, and a plurality of directional antennas 7a to 7f are arranged at predetermined angular intervals in a specific azimuth range in the horizontal plane. Although the point is the same as the conventional one, in the present invention, S1 of the switch 6
Delay lines 8a to 8f are inserted between the switching input terminals of S6 and the output terminals of the directional antennas 7a to 7f.

The delay times of the delay lines 8a to 8f are set as follows. That is, the signal transmission time from the omnidirectional antenna 1 to the signal detector 2 is T1, the signal transmission time from the signal detector 2 to the switch 6 is T2, and the switching times between the respective switching input terminals of the switch 6 are all equal to T3. To do. Also, the signal transmission time from the directional antenna 7a to the switching input terminal S1 when the delay line 8a is not provided is Ta,
Similarly, from the directional aerial directivity antenna 7b to the switching input terminal S2
Tb, the signal transmission time from the directional antenna 7c to the switching input terminal S3 is Tc, and the directional antenna 7
The signal transmission time from d to the switching input terminal S4 is Td, the signal transmission time from the directional antenna 7e to the switching input terminal S5 is Te, and the signal transmission time from the directional antenna 7f to the switching input terminal S6 is Tf.

Then, the trigger signal is input from the signal detector 2 to the switch 6, and the reception signal of the directional antenna corresponding to the switching input end is input at the timing when the switching input end is selected. Therefore, the delay time of the delay line 8a is T1 + T2-Ta because it is not necessary to consider the switching time. On the other hand, in the delay lines 8b to 8f, it is necessary to consider the switching time.
The delay time of the delay line 8b is T1 + T2 + T3-
Tb, and the delay time of the delay line 8c is T1 +
T2 + 2 * T3-Tc, the delay time of the delay line 8d is T1 + T2 + 3 * T3-Td, and the delay time of the delay line 8e is T1 + T2 + 4 * T3-T.
e, and the delay time of the delay line 8f is T1 + T
It becomes 2 + 5 × T3-Tf.

By setting the delay time of each delay line of 8a to 8f as described above, even if the pulse width of the received radio wave is narrow, the switch 6 can reliably receive the received signals of all the directional antennas 7a to 7f. Therefore, the signal can be output to the pulse amplitude detector 5 as a signal at the same time as the time received by the omnidirectional antenna 1.

Here, each of the delay lines 8a to 8f needs to have a delay time of about 0.2 μsec, but since the signal to be handled is in the microwave band, a coaxial cable of several tens of meters is used. The method is unsuitable because of large size / weight and transmission loss. Therefore, in the present invention, although not shown, an optical fiber type delay line or a superconducting type delay line is used.

The optical fiber type delay line is a photoelectric converter (E
/ O, O / E) and an optical fiber of appropriate length,
Low loss and small size and light weight are possible. Also,
The superconducting delay line is composed of a stripline type superconducting delay line and a cooler. The superconducting delay line is formed by fine processing technology to reduce the size of the delay line, and also cools the superconducting material to solve the transmission loss problem. It is like that.

In the first embodiment, since the directional antennas 7a to 7f are arranged so as to point in a specific azimuth range within the horizontal plane, they may be constructed by a multi-beam antenna. As is well known, a multi-beam antenna has a plurality of feeds and forms a plurality of receive beams having a constant beam spacing in a horizontal plane from a single antenna aperture.

As shown in FIG. 2, the directional antennas 7a to 7f may be arranged at predetermined angular intervals in all directions in a horizontal plane. Further, although not shown, an omnidirectional antenna having a spherical omnidirectional characteristic may be used, and a plurality of directional antennas may be arranged in a predetermined angular interval by directing in the entire azimuth range of the spherical surface.

[0023]

As described above, in the radio wave direction-of-arrival detecting apparatus according to the present invention, at least the switching time difference between the switches between each output terminal of the plurality of directional antennas and the corresponding input terminal of the switch. A delay line having an amount of delay is inserted to adjust the timing at which each switching input terminal of the switch is selected and the timing at which a received signal arrives at each switching input terminal. Even if the switching time is too short to be ignored, the switch can reliably switch and output the received signal of all directional antennas without extinction, so even if a narrow pulse width radio wave arrives, the direction of arrival of the radio wave Has the effect of accurately detecting

[Brief description of drawings]

FIG. 1 is a configuration block diagram of a radio wave arrival direction detecting device according to a first embodiment of the present invention.

FIG. 2 is a configuration block diagram of a radio wave arrival direction detecting device according to a second embodiment of the present invention.

FIG. 3 is a configuration block diagram of a conventional radio wave arrival direction detection device.

[Explanation of symbols]

 Reference Signs List 1 omnidirectional antenna 2 signal detector 3 receiver 4 signal processor 5 pulse amplitude detector 6 switch 7a to 7f directional antenna 8a to 8f delay line

Claims (7)

[Claims] 1. An omnidirectional antenna for detecting incoming radio waves;
A plurality of directional antennas for detecting the direction of incoming radio waves;
A switch for switching and outputting, in a predetermined order, received signals of a plurality of directional antennas in response to detection of radio waves in the omnidirectional antenna; A delay line having at least a delay amount corresponding to a switch switching time difference is inserted between each output terminal of the switch and a corresponding input terminal of the switch. 2. The omnidirectional antenna has an omnidirectional characteristic in a horizontal plane; and the plurality of directional antennas are arranged at predetermined angular intervals in a specific azimuth range in the horizontal plane. The radio wave arrival direction detecting device according to claim 1, wherein 3. The radio wave direction-of-arrival locating device according to claim 2, wherein the plurality of directional antennas are multi-beam antennas. 4. The omnidirectional antenna has an omnidirectional characteristic in a horizontal plane; the plurality of directional antennas are arranged at predetermined angular intervals in all directions in the horizontal plane. The radio wave arrival direction detecting device according to claim 1, wherein 5. An omnidirectional antenna has a spherical omnidirectional characteristic; a plurality of directional antennas are directed at an entire azimuth range of a spherical surface and are arranged at a predetermined angular interval. The radio wave arrival direction detection device according to claim 1. 6. The radio wave arrival direction according to claim 1, wherein the delay line is an optical fiber delay line. Detector. 7. The radio wave arrival direction detecting device according to claim 1, wherein the delay line is a superconducting delay line. apparatus.