JPH0579951B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a radar device that searches for targets on the ground or sea surface, and more particularly to a radar device that aims to improve azimuth resolution.

[Conventional technology]

Figure 4 is a diagram showing the configuration of a conventional radar device, for example Introduction to Radar System (MI
Written by SKOLNIK, McGRAW-HILL
The principle explanation is shown in KOGAKUSHA Publishing). In the figure, 1 is a transmitter that generates a transmission pulse signal every predetermined pulse repetition period, 2 is a transmitter/receiver switch, 3 is an antenna, 4 is a local oscillator, and 5 is an output signal of the transmitter/receiver switcher 2 and a local oscillator 4. 6 is an intermediate frequency amplifier, 7 is an amplitude detector, and 8 is an amplitude detector 7.
a pulse integrator for improving the signal-to-noise power ratio of the output signal; 9 is an indicator;

Next, the operation will be explained. A transmission pulse signal generated by a transmitter 1 is radiated to an external space from an antenna 3 via a transmitter/receiver switch 2. On the other hand, the reception signal received by the antenna 3 is input to the mixer 5 via the transmission/reception 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 amplitude detector 7 at the subsequent stage, and inputted 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, targets on the ground or sea surface can be searched for and detected.

[Problem to be solved by the invention]

Since conventional radar equipment is configured as described above, the azimuth resolution of the radar is determined by the antenna beam width, and is generally 1.5 of the antenna beam width.
It will be about double. Therefore, there was a problem in that a large antenna had to be used in order to improve the azimuth resolution.

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

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

[Means to solve the problem]

A radar device according to the present invention includes a horizontal uniaxial monopulse antenna, a gain adjuster and an amplitude detector in the sum channel thereof, and a subtracter that calculates the difference between the output signals of the amplitude detectors of both channels;
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, in the radar device according to another invention of the present invention, in the above-mentioned one, a horizontal and vertical two-axis monopulse antenna is used instead of the horizontal one-axis monopulse antenna, and a difference pattern in the horizontal or vertical direction is used. A switch for selecting one of the received signals and an attitude detector for detecting the roll angle of the radar platform are added.

[Effect]

The radar device of the present invention subtracts the amplitude-detected signal received in the difference pattern and subjected to gain adjustment from the amplitude-detected signal received in the sum pattern of the horizontal uniaxial monopulse antenna, and removes the negative amplitude component. Equivalently narrow the antenna beam width,
The lateral resolution is improved by performing pulse integration in a number matching the beam width.

Further, in another aspect of the present invention, the radar can be operated by selecting either the received signal in the horizontal or vertical direction difference pattern depending on the roll angle of the radar platform and performing the same signal processing as above. - Improving azimuth resolution by equivalently narrowing the antenna beam width even if the platform rolls.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is a transmitter that generates a transmission pulse signal at every predetermined pulse repetition period, 2 is a transmitter/receiver switch, 10 is a horizontal uniaxial monopulse antenna, 4 is a local oscillator, and 11 is a uniaxial monopulse antenna. 10 is a sum channel processing unit that processes the received signal in a sum pattern, 12 is a difference channel processor that processes the received signal in a difference pattern of the uniaxial monopulse antenna 10, and 5 is a sum channel processor 11 and a difference channel processor. 12 is a mixer, 6 is an intermediate frequency amplifier, 7 is an amplitude detector, 1
3 is a gain adjuster that changes the amplitude gain in the difference channel processor 12, 14 is a gain controller that controls the gain of the gain adjuster 13, 15 is a subtracter, and 16 is a negative amplitude of the output signal of the subtracter 15. 8 is a pulse integrator that improves the signal-to-noise power ratio of the output signal of the half-wave rectifier 16; 9 is a display.

Next, the operation will be explained using FIGS. 1 and 2. FIG. 2 is an explanatory diagram of the operation of this invention.

A transmission pulse signal generated by a transmitter 1 is transmitted via a transmitter/receiver switch 2 to an external space from a horizontal uniaxial monopulse antenna 10. On the other hand, the received signal Σ in the sum pattern of the uniaxial monopulse antenna 10 in the horizontal direction is input to the sum channel processor 11 via the transmission/reception switch 2 . In the sum channel processor 11, the received signal Σ in the sum pattern is frequency-converted by the mixer 5 using the local oscillation signal output from the local oscillator 4, and becomes an intermediate frequency signal, which is input to the intermediate frequency amplifier 6, and then input to the amplifier amplitude detector 7. The wave is detected by At this time, since the uniaxial monopulse antenna is scanning in the azimuth direction at a constant speed,
The amplitude detector 7 in the sum channel processor 11 outputs a signal as shown in FIG. It is well known to those skilled in the art that the spread of this envelope determines the azimuth resolution of the radar. Also,
The received signal ΔAz in the difference pattern of the horizontal uniaxial monopulse antenna 10 is input to the difference channel processor 12 . In the difference channel processor 12, the mixer 5 receives the received signal ΔAz in the above pattern.
is a local oscillation signal output from the local oscillator 4, which is converted into an intermediate frequency signal, amplified by the intermediate frequency amplifier 6, and then input to the gain adjuster 13. Gain adjuster 1
3, the amplification gain of the received signal is changed according to a command from the gain controller 14, and the signal is detected by the amplitude detector 7. The output signal of the amplitude detector 7 is as shown in FIG. 2b based on the principle of a monopulse antenna. Subtractor 15
Then, by subtracting the output signal of the amplitude detector 7 in the difference channel processor 12 from the output signal of the amplitude detector 7 in the sum channel processor 11, a signal waveform as shown in FIG. 2c is obtained. Here, 18 is the envelope when the amplification gain of the gain adjuster 13 is low, and 19
is an envelope when the amplification gain of the gain adjuster 13 is high. The spread of the envelope of the output signal of the subtractor 15 is controlled by the commands of the gain controller 14. In other words, the antenna beam width can be equivalently narrowed. In the half-wave rectifier 16, the subtracter 15
The negative amplitude component of the output of pulse integrator 8 is removed.
Enter. In the pulse integrator 8, the number of integrated pulses matching the equivalently narrowed antenna beam width is selected by the command of the gain controller 13, and the signal-to-noise power ratio of the received signal is improved, and the signal is displayed on the display 9.
will be displayed.

Further, FIG. 3 is a block diagram showing an embodiment of another invention of this invention, and in the figure, 1, 2, 4 to
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; 21 is a switch for selecting either the received signal in the horizontal direction or the vertical direction difference pattern of the two-axis monopulse antenna in the horizontal and vertical directions; This 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 causes the switch 21 to detect the horizontal difference pattern of the horizontal and vertical two-axis monopulse antenna 20. Difference channel processor 1 converts the received signal △Az into
2. Further, for example, when the roll angle of the radar platform is 90 degrees, the received signal ΔEL in the vertical direction difference pattern is input to the difference channel processing section 12 in the same manner as described above. 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 completely the same as the operations of the present invention described above with reference to FIGS. 1 and 2. are the same.

〔Effect of the invention〕

As explained above, this invention subtracts the gain-adjusted amplitude detection signal received in the difference pattern from the amplitude detected signal received in the sum pattern of the horizontal uniaxial monopulse antenna, and removes the negative amplitude component. Find the antenna beam width equivalently,
There is an effect that the azimuth resolution can be improved by performing reception pulse integration in a number matching the 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 the received signal depending on the roll angle of the radar platform. By performing the same signal processing as above, even when the radar platform rolls, the antenna beam width is equivalently determined and the azimuth resolution is improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of this invention, FIG. 2 is an explanatory diagram of the operation of this invention, FIG. 3 is a block diagram showing another embodiment of this invention, and FIG.
The figure is a configuration diagram of a conventional radar device. In the figure, 1 is a transmitter, 2 is a transmitter/receiver switch, and 3 is a transmitter.
is an antenna, 4 is a local oscillator, 5 is a mixer, 6 is an intermediate frequency amplifier, 7 is an amplitude detector, 8 is a pulse integrator, 9 is a display, 10 is a horizontal uniaxial monopulse antenna, 11 is a sum channel processing vessel,
12 is a difference channel processor, 13 is a gain adjuster,
14 is a gain controller, 15 is a subtracter, 16 is a half-wave rectifier, 17 is an envelope of the output amplitude of the sum channel amplitude detector, 18 and 19 are envelopes of the output amplitude of the subtracter, 20 is a horizontal and vertical 21 is a switch, and 22 is an attitude detector. In each figure, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] 1. A uniaxial monopulse antenna in the horizontal direction, and an amplitude detector in the sum channel that processes the received signal in the sum pattern of the uniaxial monopulse antenna.
The difference channel that processes the received signal in the difference pattern of the above-mentioned uniaxial monopulse antenna 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, which detects the amplitude of both channels. A subtracter that calculates the difference between the output signals of the detector, a half-wave rectifier that removes the negative amplitude component of the output signal of the subtracter, and the output of the half-wave rectifier are input, and the output signal is inputted according to the command of the gain controller. A radar device comprising a pulse integrator that can change the number of integrated pulses. 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 to detect the difference in the horizontal or vertical direction of the two-axis monopulse antenna. There is a switch that selects one of the received signals in the pattern, a difference channel that processes the output signal of this switch, 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. 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 the subtracter, and an input of the output of the half-wave rectifier. , is equipped with a pulse integrator that can change the number of integrated pulses according to commands from the gain controller, and an attitude detector that detects the roll angle of the radar platform. A radar device characterized in that it is configured to select one of the received signals in the difference pattern.