JPH0238886A - Radar - Google Patents

Abstract

PURPOSE:To achieve higher bearing resolutions by performing a specified processing of sum and difference pattern output of a single-axis monopulse radar to use a difference output thereof with the removal of a negative amplitude component therefrom. CONSTITUTION:A sum pattern output given with a single-axis monopulse antenna 10 and a transmission/reception switch 2 is detected with a mixer 5, an IF amplifier 6 and an amplitude detector 7 of a sum channel element 11 to be supplied to a subtractor 15. A difference pattern signal from the antenna 10 is processed with an identical difference channel processor 12 additionally having a gain adjuster 13 and a detection output is supplied to the subtractor 15. Then, a negative amplitude component is removed with a half- wave detector 16 from a difference signal from the subtractor 15 to narrow an antenna beam width equivalently and a pulse width the number thereof matching the beam width are integrated with a pulse integrator 8 to be supplied to a display device 9 as a signal with a higher S/N ratio. This achieves higher bearing resolutions without a growing size of the antenna.

Description

[Detailed Description of the Invention] [Industrial Applicability] This invention relates to a radar device for searching for targets on the ground or on the sea surface, and more particularly, relates to a radar device aimed at improving azimuth resolution. .

[Conventional technology]

FIG. 4 is a diagram showing the configuration of a conventional radar device.
stems (M, written by KOLNIK, M cG R
The principle explanation is shown in AW-HILL KOG person KUSH person appearance #Ji1. In the figure, (1) is a transmitter that generates a transmission pulse signal every predetermined pulse repetition period;
(2) is the transmitter/receiver switch 2 (3) is the antenna, (4) is the local oscillator, and (5) is the output signal of the transmitter/receiver switcher (2) and the local oscillator! 2 M (mixer that mixes the output signal of 41 and converts it to an intermediate frequency, (6) is the intermediate frequency amplifier i71 is the amplitude detector, (8) is the signal-to-noise power ratio of the output signal of the amplitude detector (7) (9) is an indicator.

Next, the operation will be explained. The transmission pulse signal generated by the transmitter (1) is sent to the antenna (3) via the transmission/reception switch (2).
) should be radiated into the external space. On the other hand, the received signal received by the antenna (3) is input to the mixer (5) via the transmitter/receiver switch (2). The received signal is frequency-converted by the mixer (5) using a local oscillation signal output from the local oscillator (4) to become an intermediate frequency signal, which is input to the intermediate frequency amplifier (6). The intermediate frequency signal is amplified by the intermediate frequency amplifier (6), detected by the subsequent amplitude detector (7), and input to the pulse integrator (8). The pulse integrator (8) improves the signal-to-noise power ratio of the received signal and displays it on the display (9). By performing this series of operations while rotating the antenna (3) in the azimuth direction, it is possible to search for and detect targets on the ground or on the sea surface.

[Problem to be solved by the invention]

Conventional radar equipment is configured as described above, so
The azimuth resolution of the radar is determined by the antenna beam width, −
For boat fishing, it will be about 1.5 times the antenna beam width. Therefore, there was a problem in that a large antenna had to be used to improve the azimuth resolution.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to obtain a radar device that can improve the azimuth resolution of radar without using a large antenna with a narrow beam width.

Another object of the present invention is to obtain a radar device that can improve azimuth resolution even when the radar platform rolls.

[Means to solve the problem]

The radar device according to the present invention includes a horizontal uniaxial monopulse antenna, an amplitude detector for the sum channel, a gain adjuster and an amplitude detector for the difference channel, and a difference between the output signals of the amplitude detectors for both channels. a subtractor that calculates
A half-wave rectifier and a pulse integrator are provided at the subsequent stage to remove the negative amplitude component of the output signal of the subtracter.

Further, there is a radar device according to another invention of the present invention.

In the above, a horizontal and vertical dual-axis monopulse antenna is used instead of a horizontal single-axis monopulse antenna, and a switch and a radar antenna are used to select either the received signal in the horizontal or vertical difference pattern. It is equipped with an attitude detector that detects the roll angle of the platform.

[For production]

In this invention, the Reig device+! , the amplitude-detected signal received in the difference pattern and subjected to gain adjustment is subtracted from the amplitude-detected signal received in the sum pattern of the horizontal uniaxial monopulse antenna, and the negative amplitude component is removed to equivalently form the antenna beam. The lateral resolution is improved by narrowing the beam width and performing pulse integration in a number matching the beam width.

Further, in another aspect of the present invention, the same signal processing as described above is performed by selecting either the horizontal or vertical received signal at the differential Bakun depending on the roll angle of the 1-noder platform. This effectively determines the antenna beam width even when the radar platform rolls, improving azimuth resolution.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, (1) is a transmitter that generates a transmission pulse signal at every predetermined pulse repetition period, and (2) is a transmitter/receiver switch 1.0.
1 is a horizontal uniaxial monopulse antenna, (4) is a local oscillator i! , (+1) is a sum channel processing W that performs reception in the sum pattern of the uniaxial monopulse antenna signal (g processing), (+2) is a difference channel processor that processes the received signal in the difference pattern of the uniaxial monopulse antenna 0α ,
(5) is the mixer in the sum channel processing i1 (11) and the difference channel processor (I2), (6) is the intermediate frequency amplifier, (7) is the amplitude detector, (131 differential channel processing type (121) a gain adjuster that changes the amplitude gain;
(14) is a gain control II device that controls the gain of the gain adjuster (13), (Is) is a subtractor, (16) is a subtractor (
+5) is a half-wave rectifier that removes the negative amplitude component of the output signal; (8) is a pulse integrator that improves the signal-to-noise power ratio of the output signal of the half-wave rectifier (16); (91 is an indicator) .

Next, the operation will be explained using FIGS. 1 and 2.

FIG. 2 is an explanatory diagram of the operation of this invention.

The transmission pulse signal generated by the transmitter IN device (1) is sent to the horizontal uniaxial monopulse antenna (
101 and is projected into the external space. On the other hand, the received signal Σ in the sum pattern of the horizontal uniaxial monopulse antenna 0 is sent to the sum channel processor (1) via the transmit/receive switch (2).
1) is input. In the sum channel processor (II), the mixer (5) receives the 4M signal Σ in the above sum pattern (the frequency is converted by the local oscillation signal output from the local oscillator (4) to an intermediate frequency signal, and the intermediate frequency amplifier (6) ) is amplified and detected by the amplitude detector (7).At this time, since the uniaxial monopulse antenna is scanning in the azimuth direction at a constant speed, the signal shown in Figure 2 (arrow) is generated. Sum channel processing u (outputted from the amplitude detector (7) in 111, this signal waveform is the same as in the case of conventional radar equipment, and (17) shows the envelope of the above signal waveform.
It is well known to those skilled in the art that the spread of this envelope determines the azimuth resolution of the radar.

Also.

Horizontal uniaxial mono zf russ antenna 0 [difference) received signal at f turn 6 people 2 is difference channel processor (12)
be entered into. In the difference channel processor (12).

The received signal ΔAz in the above pattern is converted into an intermediate frequency signal by the mixer (5) using a local oscillation signal outputted by the local oscillator (4), amplified by the intermediate frequency amplifier (6), and then input to the gain adjuster (13). be done. The gain adjuster (13) changes the amplification gain of the received signal in response to a command from the gain controller (14), and the received signal is detected by the amplitude detector M (7). This amplitude detection W
Based on the principle of a monopulse antenna, the output signal of +71 is as shown in Figure 2 (bl).The subtracter (15) converts the output signal of the amplitude detector (7) in the sum channel processor (11) to the difference channel processor. A signal waveform as shown in Fig. 2(e) is obtained by multiplying the output signal of the amplitude detector (7) in (12) by 18. Here, (18) l is the gain adjuster (1).
(3) is the envelope when the amplification gain is low; (19) is the envelope when the amplification gain of the gain: A amplifier (13) is high. In this way, the spread of the envelope of the output signal of the subtractor (15) is controlled by the command of the gain controller (14).

In other words, it is possible to equivalently narrow the antenna beam width. The half-wave rectifier (16) removes the negative amplitude component of the output of the subtracter (+5) and inputs it to the pulse integrator (8). In the pulse integrator (8), the number of integrated pulses matched to the equivalently narrowed antenna beam width is determined by the gain control fal
(13), the signal-to-noise power ratio of the received signal is improved and displayed on the display (9).

Further, FIG. 3 is a block diagram showing an embodiment of another invention of the present invention, and in FIG. 2, fil, (21, T41~
(9) and (11) to (16) are exactly the same as shown in FIG. (20) is a two-axis monopulse antenna in the horizontal and vertical directions, and (21) is a two-axis monopulse antenna in the horizontal and vertical directions. The selection switch (22) is an attitude detector that detects the roll angle of the radar platform.

Next, the operation will be explained. When the roll angle of the radar platform is 0 degrees, the attitude detector (22) switches (2I) the received signal 6 in the horizontal difference pattern of the horizontal and vertical two-axis monopulse antenna (20).
2. For example, if the roll angle of the radar platform is 90 degrees.

In the same way as above, the received signal Δ in the vertical direction difference pattern is
Input EL to the difference channel processing type (+2).

In this way, the received signal input to the differential channel processor (12) is switched according to the roll angle of the radar platform, and the other operations are as described above with reference to FIGS. 1 and 2. is exactly the same.

〔Effect of the invention〕

As explained above, this invention subtracts the amplitude detected signal received in the difference pattern and subjected to gain p4 adjustment from the signal received in the sum pattern of the horizontal uniaxial monopulse antenna and subjected to amplitude detection, thereby removing the negative amplitude component. This has the effect of improving the azimuth resolution by equivalently narrowing the antenna beam width and integrating the received pulses matched to this beam width.

Another invention of the present invention uses a horizontal and vertical dual-axis monopulse antenna to select either the horizontal or vertical differential pattern of received signals depending on the roll angle of the radar platform. By performing the same signal processing as above, even if the relay platform rolls, the antenna beam width is equivalently narrowed and the azimuth resolution is improved.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing one embodiment of the present invention, Fig. 2 is an explanatory diagram of the operation of this investigation, Fig. 3 is a block diagram showing an embodiment in another investigation of this investigation, and Fig. 4 (This is a configuration diagram of a conventional radar device. In the figure, (1) is a transmitter, (21 is a transmitting/receiving switching type, f
31 is the antenna, (4) is the local oscillation! , (51 is a mixer, (6) is an intermediate frequency amplifier, (7) is an amplitude detector, (8
) is a pulse integrator, (9) is a display, 0 is a horizontal uniaxial monopulse antenna, (IIJ sum channel processing tlil!, (12) is a difference channel processor,
(+3) is a gain adjuster, (141 is a gain control tn device,
(Is) l is the subtractor, (16] is the half-wave rectifier. (+71 + envelope of the output amplitude of the amplitude detector of the Shōwa channel, (18) and (19) are the envelopes of the output amplitude of the subtractor. ( 20) is a horizontal and vertical two-axis monopulse antenna, (21) is a switch, and (22) is an attitude detector. In each figure, the same reference numerals indicate the same or equivalent parts. Masuo Iwa

Claims (2)

[Claims] (1) A uniaxial monopulse antenna in the horizontal direction, and an amplitude detector for the sum channel that processes the received signal in the sum pattern of this uniaxial monopulse antenna, and processes the received signal in the difference pattern of the uniaxial monopulse antenna. The difference channel is equipped with a gain adjuster that changes the amplifier gain according to the command of the gain controller, and an amplitude detector at the subsequent stage.
A subtracter that calculates the difference between the output signals of the amplitude detectors of both channels, a half-wave rectifier that removes the negative amplitude component of the output signal of this subtracter, and the number of integral pulses is changed by the command of the gain controller. What is claimed is: 1. A radar device characterized by comprising a pulse integrator capable of (2) A two-axis monopulse antenna in the horizontal and vertical directions, an amplitude detector for the sum channel that processes the received signal in the sum pattern of the two-axis monopulse antenna, and an amplitude detector in the horizontal or vertical direction of the two-axis monopulse antenna. a switch for selecting one of the received signals in the difference pattern;
The difference channel that processes the output signal of this switch is equipped with a gain adjuster that changes the gain of the amplifier according to the command of the gain controller, and an amplitude detector at the subsequent stage, and the difference between the output signals of the amplitude detectors of both channels is provided. a subtracter that calculates the value of A radar device comprising an attitude detector for detecting an angle, and configured to select either a received signal in a horizontal or vertical difference pattern using the switch according to a change in the roll angle. .