JP2000258521A - Direction finder and direction finding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a correct arrival direction from a target by removing a radar wave and an unwanted wave returning from a target through a pulse repetition frequency synchronism filter(PRI filter) thereby separating the unwanted wave. SOLUTION: A signal group received by a rotary antenna 1 is narrowed down to the frequencies in the proximity of a target frequency by a tuning receiver 2 and unwanted waves causing false direction is included therein. Filtering is performed through use of a PRI filter 6 passing only the pulse repetition frequency(PRF) of the target in order to extract only the target. Subsequently, a direction detector 5 detects the arrival direction of the target in congested radio wave environment by indicating the arrival direction of a signal from the target, along with the strength thereof, with a rotational angle signal (digital) 3b obtained through S/D(synchro/digital) conversion of a rotational angle signal (synchro) 3a from the rotary antenna 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an azimuth detecting apparatus and method, and more particularly to an azimuth detecting apparatus and method using an ESM (Electronic Support Measure: radio wave detecting function).

[0002]

2. Description of the Related Art Since a frequency band used by a radar detector is managed by a radio control station, frequencies used by a plurality of radar detectors are generally close to each other. Therefore, E
In an azimuth detecting apparatus and method using an SM, a radar wave reflected and returned from a target whose azimuth is to be detected (hereinafter, referred to as a “target target”) and another target different from the target target (hereinafter, “another target”) ) And another radar wave (hereinafter referred to as “unnecessary wave”) reflected and returned from the antenna.

FIG. 3 shows a conventional direction detecting device. FIG.
, Reference numeral 1 denotes a broadband rotary antenna for receiving incoming radio waves returned from a target and another target, 2 denotes a tuned receiver for receiving a frequency near the frequency of the target, 3a denotes angle information of the rotary antenna 1 (Analog signal), 4 is an S / D converter for converting angle information (analog signal) 3a into a digital signal 3b, and 3b is a rotary antenna 1 converted from an analog signal to a digital signal by the S / D converter 4. Angle information 5 is an azimuth detector for calculating the azimuth at which a radar wave arrives from a target by combining the output of the tuning receiver 2 and the angle signal (digital) 3b of the rotary antenna 1.

Next, the operation will be described. A signal group including a radar radio wave and an unnecessary wave reflected from the target and received by the rotary antenna 1 is input to a tuning receiver 2 connected to the rotary antenna 1 and the frequency of the radio wave of the target is received. The frequency is reduced to a nearby frequency, and then input to the azimuth detector 5 connected to the tuning receiver 2. On the other hand, the angle signal (analog) 3a of the antenna of the rotary antenna 1 is converted into a digital signal 3b by the S / D converter 4 and input to the azimuth detector 5 connected to the S / D converter 4. Direction detector 5
Inputs the signal received by the rotary antenna 1 and the digitized signal 3b of the angle signal (analog) 3a of the rotary antenna 1 at that time, and detects the arrival direction of the signal returned from the target. I was

[0005]

However, in the conventional azimuth detecting device, the signal received by the rotary antenna 1 as described above includes a radar wave and an unnecessary wave reflected and returned from the target. If the radar wave reflected from the target is not separated from the unwanted wave because it is often mixed, there is a problem in that the direction in which the radar wave reflected from the target arrives is often erroneously detected. Was. Therefore, an object of the present invention is to solve the above-described problem, and it is an azimuth detection method that can detect a correct direction of arrival from a target by separating radar waves and unnecessary waves returned from the target. It is to provide an apparatus and a method.

[0006]

An azimuth detecting device according to the present invention comprises: a rotary antenna for receiving a pulsed radar wave returned from a target and a target different from the target; A tuned receiver that receives a received pulsed radar wave and outputs a radar wave near the target frequency, and receives a pulsed radar wave near the target frequency output from the tuned receiver. An analog pulse repetition interval filter that passes only the signal of the target target pulse repetition frequency; and a synchro / digital converter that inputs a synchro signal indicating the rotation angle of the rotary antenna and converts it into a digital signal. A signal having only a pulse repetition frequency of a target which has passed through the analog pulse repetition interval filter, Enter a digital signal indicating the rotation angle of the converted the rotary antenna by Le converter, in which a direction detector for detecting the azimuth of the target goal. The azimuth detecting device of the present invention is a rotary antenna for receiving pulsed radar waves returned from a target and a target different from the target, and a pulsed radar wave received by the rotary antenna. A tuned receiver for inputting and outputting a radar wave near a target frequency; a synchro / digital converter for inputting a synchro signal indicating a rotation angle of the rotary antenna and converting it into a digital signal; An analog / digital converter for inputting a radar wave near the frequency of the target output from the machine and converting it into a digital signal indicating information of the radar wave near the frequency of the target; and the analog / digital converter. The synchro / digital converter converts the digital signal into a signal indicating radar wave information in the vicinity of the target frequency. An attachment unit that attaches and outputs a signal indicating the rotation angle converted to a digital signal, and a digital pulse repetition interval filter that receives the output of the attachment unit and passes only the signal of the target target pulse repetition frequency. And an azimuth detector for detecting the azimuth of the target by inputting a signal passed through the digital pulse repetition interval filter. here,
In the azimuth detecting device according to the present invention, the attachment unit further includes a storage unit that stores a signal indicating information of a radar wave near a frequency of a target which is converted into a digital signal by the analog / digital converter. A signal indicating a rotation angle converted into a digital signal by the synchro / digital converter after the signal indicating the information of the radar wave near the frequency of the target stored in the storage unit; It can output a signal indicating radar wave information near a target frequency and a signal indicating a rotation angle.

According to the azimuth detecting method of the present invention, a radar wave receiving step of receiving a pulsed radar wave returned from a target and a target different from the target by a rotary antenna, and the radar wave receiving step. A tuned receiving step of inputting the received pulsed radar wave and outputting a radar wave near the target target frequency, and inputting a pulsed radar wave near the target target frequency output by the tuned receiving step An analog pulse repetition interval filter processing step of passing only a signal of the target target pulse repetition frequency, and a synchro / digital conversion step of inputting a synchro signal indicating the rotation angle of the rotary antenna and converting it into a digital signal And the pair passed by the analog pulse repetition interval filtering step. An azimuth detecting step of inputting a signal of only the target pulse repetition frequency and a digital signal indicating the rotation angle of the rotary antenna converted by the synchro / digital conversion step, and detecting an azimuth of the target target; It is a thing. In the azimuth detecting method according to the present invention, a radar wave receiving step of receiving a pulse-shaped radar wave returned from a target target and a target different from the target target by a rotary antenna, and the radar wave receiving step is received by the radar wave receiving step. A tuning receiving step of receiving a pulse-like radar wave and outputting a radar wave near the target frequency, and a synchro / digital conversion of receiving a synchro signal indicating a rotation angle of the rotary antenna and converting it into a digital signal Step, input a radar wave near the frequency of the target target output by the tuning receiving step,
An analog / digital conversion step of converting a radar signal in the vicinity of the target frequency into a digital signal indicating information on the radar wave; and information on the radar wave in the vicinity of the target frequency converted into a digital signal by the analog / digital conversion step. An attaching step of attaching a signal indicating a rotation angle converted into a digital signal by the synchro / digital converter to the signal and outputting the signal; and inputting the output of the attaching step to input a signal having only the pulse repetition frequency of the target. A digital pulse repetition interval filter processing step to be passed; and an azimuth detection step of inputting a signal passed through the digital pulse repetition interval filter processing step and detecting an azimuth of a target.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. Embodiment 1 FIG. FIG. 1 shows an azimuth detecting device according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 1 denotes a broadband rotary antenna for receiving incoming radio waves returned from a target and another target, 2 denotes a tuned receiver for receiving a frequency near the frequency of the target, and 6 denotes a tuned receiver transmitted from the target. (Input) type pulse repetition interval synchronization (Pulse Re
petition Interval (PRI) filter, 3a: fine rotation angle information (synchro signal) of rotary antenna 1; 4: synchro / digital (S / S) for converting rotation angle information (synchro signal) 3a to digital signal 3b
D) a converter, 3b: rotation angle information of the rotary antenna 1 converted from a synchro signal to a digital signal by the S / D converter 4, 5: an output of the analog (input) type PRI filter 6 and the rotary antenna 1 This is an azimuth detector that calculates the azimuth at which the radar wave from the target target arrives by combining the rotation angle signal (digital) 3b of FIG.

In the first embodiment, an unnecessary wave existing near the frequency of the radar wave returned from the target is converted into a PRI.
Since the signal can be suppressed by the filter 6, the signal of the radar wave input to the azimuth detector 5 is only the signal returned from the target. The PRI filter 6 has a pulse repetition frequency (Pulse Repetition Frequency) radiated by the pulse radar.
: PRF) is a filter that passes only signals synchronized with the interval of (PRF). For example, if the distance from the radar detection device to the target is 300 km, that is, 600 km round trip,
The time required for a radar wave to go and return is 600 km / light speed c =
2 ms. Therefore, a radar detection apparatus for a target target up to a distance of 300 km uses a PRF of 2 ms or more, in other words, a PRF of 500 Hz or less. In this case, the PRI filter 6 may be a filter that passes only a signal synchronized with 500 Hz. As described above, the signal group received by the rotary antenna 1 is narrowed down to a frequency near the frequency of the target target by the tuning receiver 2, but includes unnecessary waves (a plurality of radar waves) as a source of a false azimuth. . Therefore, in order to extract only the target target, filter processing is performed using the PRI filter 6 that passes only the pulse repetition frequency PRF of the target target. Thereafter, a rotation angle signal (digital) obtained by S / D converting the rotation angle signal (synchro) 3a of the rotary antenna 1 to the azimuth detector 5
By displaying the direction of arrival of the signal from the target target together with its intensity in 3b, the direction of arrival of the target target in a congested radio wave environment can be detected.

As described above, according to the first embodiment, in order to extract only the target target, the filter processing is performed using the PRI filter that passes only the pulse repetition frequency PRF of the target target. Since the azimuth can be detected only by the obtained signal, the arrival azimuth of the target in the congested radio wave environment can be detected.

Embodiment 2 FIG. 2 shows an azimuth detecting device according to Embodiment 2 of the present invention. 2 having the same reference numerals as those in FIG. 1 have the same functions, and the description thereof will be omitted. 2, reference numeral 1 denotes a rotary antenna, 2 denotes a tuned receiver for extracting a signal having a frequency near a target frequency from signals received by the rotary antenna 1, and 3a denotes a rotation angle of the rotary antenna 1. Information (sync signal) 4 is rotation angle information (sync signal) 3a is converted into digital signal 3b
, 3b denotes rotation angle information of the rotary antenna 1 converted from a synchro signal to a digital signal by the S / D converter 4, and 7 denotes analog / digital (A
/ D) a data combining unit having a converter 10 and an attachment unit 11, wherein the A / D converter 10 converts a signal having a frequency near the frequency of the radar wave returned from the target extracted by the tuning receiver 2. The digital signal is converted into a digital signal, and the
The digital signal converted by the D converter 10 is S / D
Rotary antenna 1 converted to digital signal by converter 4
Attach rotation angle information. For example, the amplitude strength of the received signal is converted into 10-bit digital data by the A / D converter 10 and stored in a memory (not shown) such as a RAM. After the stored 10-bit digital data, S The rotation angle information converted into 8-bit digital data by the / D converter 4 is attached and stored, and both the stored 18 (= 10 + 8) -bit digital data are output from the data combining unit 7. The type of information converted by the A / D converter 10 is not limited to the amplitude intensity of a signal, and the bit length of data is not limited to 10 bits or the like. Referring back to FIG. 2, reference numeral 8 denotes a digital (input) PRI filter that passes a frequency near the pulse repetition frequency of the radar wave transmitted from the target, and 9 denotes a digital (input) PRI filter 8.
Is an azimuth detector that calculates the azimuth at which the radar wave arrives from the target from the output of the target, and displays the azimuth along with the intensity of the radar wave.

In the second embodiment, the signal from the target and the signal of the unnecessary wave are mixed and input to the A / D converter 10.
Since only the signal having the RI is extracted, the signal input to the direction detector 5 is only the signal from the target. As described above, the signal group received by the rotary antenna 1 is narrowed down to a frequency near the target frequency by the tuning receiver 2, and then converted from an analog signal to a digital signal by the A / D converter 10. . The reception signal converted into the digital signal includes the rotation angle signal 3a of the rotary antenna 1 as S
Rotation angle signal 3b digitally converted by A / D converter 4
Is attached by the attachment unit 11. The received signal to which the rotation angle signal 3a of the rotary antenna 1 is attached is subjected to the PRI filter processing for passing only the pulse repetition frequency PRF of the target target by the PRI filter 8, and the signal of the unnecessary wave which may be a false azimuth is deleted. You. Therefore, it is possible to detect the arrival direction of the target in a congested radio wave environment.

As described above, according to the second embodiment, the signal group received by the rotary antenna is converted into a digital signal after being narrowed down to a frequency near the target frequency, and the rotation angle signal of the rotary antenna ( (Digital) is attached, so that the data to which the rotation angle is attached can be filtered using a digital PRI filter that passes only the target target pulse repetition frequency PRF. Therefore, since the direction of arrival can be detected using only the signal returned from the target that does not include the unnecessary wave, the direction of arrival of the target in a congested radio wave environment can be detected.

[0014]

As described above, according to the azimuth detecting apparatus and method according to the present invention, the radar wave and the unnecessary wave returned from the target are used by using the pulse repetition frequency synchronous filter (PRI filter) of the target. Unnecessary waves can be separated by deleting, so that it is possible to provide an azimuth detecting device and method capable of detecting a correct azimuth from the target.

[Brief description of the drawings]

FIG. 1 is a diagram showing an azimuth detecting device according to Embodiment 1 of the present invention.

FIG. 2 is a diagram showing an azimuth detecting device according to Embodiment 2 of the present invention.

FIG. 3 is a diagram showing a conventional direction detection device.

[Explanation of symbols]

1 rotary antenna, 2 tuned receiver, 3a rotary antenna angle signal (analog), 3b rotary antenna angle signal (digital), 4 S / D converter, 5
Orientation detector, 6, 8 PRI filter, 7 A /
D converter.

Claims (5)

[Claims] 1. A rotary antenna for receiving pulsed radar waves returned from a target and a target different from the target, and a pulsed radar wave received by the rotary antenna. A tuned receiver that outputs a radar wave near the target frequency, and a pulse-shaped radar wave that is output from the tuned receiver and that is near the target frequency, and receives only a pulse repetition frequency of the target signal. An analog-type pulse repetition interval filter that passes a signal; a synchro / digital converter that inputs a synchro signal indicating the rotation angle of the rotary antenna and converts it into a digital signal; A signal of only the pulse repetition frequency of the target target and the rotary type space converted by the synchro / digital converter. Enter a digital signal indicating the rotation angle of the line, the orientation detecting device characterized by comprising a bearing detector for detecting the azimuth of the target goal. 2. A rotary antenna for receiving a pulsed radar wave returned from a target target and a target different from the target target, and a pulsed radar wave received by the rotary antenna. A tuned receiver that outputs a radar wave near the target frequency, a synchro / digital converter that inputs a synchro signal indicating the rotation angle of the rotary antenna and converts it into a digital signal, and an output from the tuned receiver. An analog-to-digital converter that inputs a radar wave near the target target frequency and converts it into a digital signal indicating information about the radar wave near the target target frequency; and a digital signal by the analog-to-digital converter. A signal indicating information of the converted radar wave near the target frequency is converted into a digital signal by the synchro / digital converter. An attachment unit that attaches and outputs a signal indicating the converted rotation angle, a digital pulse repetition interval filter that receives an output of the attachment unit and passes a signal having only a pulse repetition frequency of a target target, and the digital And an azimuth detector for detecting the azimuth of the target by inputting a signal that has passed through a pulse repetition interval filter of a formula. 3. The attachment unit further includes a storage unit that stores a signal indicating information of a radar wave near a target frequency converted into a digital signal by the analog / digital converter, and the storage unit stores the signal. A signal indicating the rotation angle converted into a digital signal by the synchro / digital converter is attached after the signal indicating the information of the radar wave in the vicinity of the target target frequency, and stored. 3. A signal indicative of information on a nearby radar wave and a signal indicative of a rotation angle are output.
The azimuth detecting device as described in the above. 4. A radar wave receiving step of receiving, via a rotary antenna, a pulsed radar wave returned from a target target and a target different from the target target, and a pulsed radar wave received by the radar wave receiving step. A tuned receiving step of inputting a radar wave and outputting a radar wave near the target target frequency, and inputting a pulse-shaped radar wave near the target target frequency output by the tuned receiving step, An analog pulse repetition interval filter processing step of passing a signal having only a pulse repetition frequency; a synchro / digital conversion step of inputting a synchro signal indicating a rotation angle of the rotary antenna and converting it into a digital signal; Pulse repetition of target target passed by repetition interval filtering step An azimuth detecting step of inputting a signal of only a wave number and a digital signal indicating the rotation angle of the rotary antenna converted by the synchro / digital conversion step, and detecting an azimuth of a target target; Direction detection method. 5. A radar wave receiving step of receiving, via a rotary antenna, a pulsed radar wave returned from a target target and a target different from the target target, and a pulsed radar wave received by the radar wave receiving step. A tuning reception step of inputting a radar wave and outputting a radar wave near a target target frequency; a synchro / digital conversion step of inputting a synchro signal indicating a rotation angle of the rotary antenna and converting it into a digital signal; An analog-to-digital conversion step of inputting a radar wave near the target frequency output by the tuning reception step and converting the radar wave to information indicating radar wave information near the target frequency; Information on radar waves near the target frequency converted to digital signals by the conversion step An attaching step of attaching a signal indicating a rotation angle converted into a digital signal by the synchro / digital converter to the indicated signal and outputting the signal, and a signal having only the pulse repetition frequency of the target by inputting the output of the attaching step A digital pulse repetition interval filter processing step of passing a signal, and a direction detection step of receiving a signal passed through the digital pulse repetition interval filter processing step and detecting a direction of a target target. How to detect.