JPH028670B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radar device that performs beam scanning electronically, and includes a beam scanning controller for original beam scanning, a phase correction amount storage circuit for antenna pattern shaping, and an adder. By installing a switch and controlling the phase shifter of the phased array antenna, the null that occurs in the antenna side roll can be reduced, and even when a launched missile attempts to fly in the null direction of the antenna, the radar transmits radio waves. The missile self-destructs by providing sufficient irradiation,
To prevent deterioration of the target tracking performance of the radar inside the missile, to form a wide beam pattern in the front direction of the antenna, and to irradiate radar transmission radio waves to missiles and targets flying within the beam pattern,
The object is to provide a radar device that can easily guide missiles.

In radar equipment using conventional mechanical scanning antennas or phased array antennas, a null-filling horn antenna with a wide beam pattern that covers the side lobes is installed near or in front of the main antenna to fill in the nulls that occur in the antenna side lobes. However, it is necessary to take out a part of the transmitted radio wave from the coupler and radiate it, and the size increases due to the installation of the Knull-Fillinghorn antenna and coupler.
There were drawbacks such as a complicated configuration. Furthermore, the radar device tracks the target using transmitted radio waves that guide the missile, and even when it is impossible to direct a pencil beam to the target, the missile can track the radar transmitted radio waves reflected from the target. It is necessary to switch the radar transmission radio waves from the main antenna to have a relatively large beam pattern, and radiate it to the missile and target from the flat horn antenna installed parallel to the antenna center axis, which requires installation of the flat horn antenna. There were disadvantages such as an increase in size and an increase in size and weight due to the addition of a switching device. This invention was made in order to eliminate such drawbacks in conventional radar equipment. Phase correction amount storage circuit in the scan controller,
With a simple configuration that only requires an adder and a switch, the phase distribution on the antenna aperture can be controlled, making it possible to easily embed nulls in the antenna side lobes and form a wide beam pattern, allowing for good missile guidance. The aim is to provide a radar device that can.

The present invention will be explained in detail below with reference to the drawings.

FIG. 1 is a diagram showing an example of the configuration of a conventional radar device. In FIG. 1, 1 is a controller, 2 is a transmitter, 3 is a transmitter/receiver switch, 4 is a phased array antenna, 5 is a target, 6 is a receiver, 7 is a signal processor,
8 is an indicator, 9 is an information processor, 10 is a beam scanning controller, 11 is a phase amount calculation control circuit, 12 is a drive circuit, 13 is a missile, 14 is a coupler, 15 is a Nullfield horn antenna, 16 is a Switch, 1
7 is a flat horn antenna, Δ is a monopulse difference channel, and Σ is a monopulse sum channel.

Next, the operation of the above radar device will be explained.

Based on the radar transmission mode selected by the controller 1, the transmitter 2 generates pulsed transmission radio waves, and sends them to the phased array antenna 4 via the transmitter/receiver switch 3. The transmitted radio waves are radiated into space from the phased array antenna 4, and the radio waves reflected by the target 5 are received by the phased array antenna 4, and are inputted again to the receiver 6 via the transmitter/receiver switch 3, where they are amplified and post-missile signal processed. The video signal is subjected to necessary processing in the device 7 and displayed on the indicator 8. Also, based on the coverage area and beam scanning pattern selected by the controller 1, when the information processor 9 sends the beam scanning angle command signal a to the phase amount calculation control circuit 11 in the beam scanning controller 10, the phase amount calculation is performed. The control circuit 11 calculates the amount of phase shift to be given to the phase shifters in a large number of antenna elements (not shown) that constitute the phased array antenna 4, and the drive circuit 12 outputs a phase shifter drive signal b. Set the phase shifter to drive.

The operator of the radar device operates the controller 1 based on the signal of the target 5 displayed on the indicator 8 to issue a tracking command. Based on this tracking command, the information processor 9 receives information about the target 5 from the signal processor 7, performs tracking processing, extracts accurate distance, angle, and speed information, displays it on the indicator 8 in symbols and numbers, and displays it on the antenna. The beam scanning angle signal a is transmitted to the beam scanning controller 1 so that the beam always irradiates the target 5.
0, and also sends a distance tracking command signal to the signal processor 7 so as to always extract only the target signal. When the target 5 is within the range of the missile 13, the operator fires the missile 13. In response to the missile launch signal, the combiner 14 combines a portion of the transmitted radio waves, and the transmitted radio waves are radiated from the Null-Filling horn antenna 15, filling in the nulls of the side lobes of the phased array antenna 4. Since the missile 13 is semi-active, the radar has a high pulse repetition frequency that is high enough to avoid target velocity uncertainty for the missile 13.
It is necessary to irradiate missile 13 and target 5 with PRF (Pulse Repeatation Frequency) or continuous waves. The semi-active missile 13 continuously receives the transmission reference signal from the side lobe of the radar's phased array antenna 15 with its rear antenna, and stabilizes the local signal for reception of the missile 13 itself in synchronization with this signal. The antenna main beam of the phased array antenna 15 of the radar receives the reflected signal from the target 5 continuously irradiated by the front antenna, and performs phase detection with the transmission reference signal received by the rear antenna. The Doppler frequency due to the relative movement between the target 5 and the missile 13 is detected. By constantly tracking this Doppler frequency, it detects the direction of the target 5, controls the direction, flies in the direction of the target 5, and when it approaches the target 5, explodes and destroys the target 5. In this way, the missile 13 needs to constantly receive radar radio waves from the front antenna and the rear antenna, and if either of these signals is interrupted, it will lose track of the signal from the target 5 and will be unable to control its direction. becomes possible and cannot be induced. By the way, at high PRF, when the target 5 approaches against the radar, the approach speed is different from the clutter caused by unnecessary reflections from the ground, etc., so the Doppler frequency surface that changes due to the approach speed It is possible to detect and track the reflected signal from the doppler frequency signal as a Doppler frequency signal. On the other hand, when Target 5 changes direction and the radar tracks it, the approach speed between the radar and Target 5 becomes slower, and there is no difference in the approach speed between the radar and the ground, and the difference between Kuratsuta's Doppler frequency and Target 5 decreases. The Doppler frequencies of the reflected signals match, making it difficult to separate them and making it impossible for the radar to track them. If the radar cannot track, the antenna main beam cannot irradiate the target 5, and the missile 13 cannot be guided. Under these circumstances, when the operator launches the missile 13, the radar switches the switch 16 to the flat horn antenna 17 with a wide beam pattern in order to irradiate the transmitted radio waves to both the target 5 and the missile 13. Emit transmitting radio waves.

In order to guide a missile, it is necessary to install a null-filling horn antenna, a flat horn antenna, a switch, and a coupler in addition to the phased array antenna, which increases the size of the device and increases the cost. In particular, it had the disadvantage that it was difficult to secure an installation space when mounting it on an aircraft. This invention has been made to improve these drawbacks.

More specifically, this invention utilizes the fact that when a quadratic phase distribution is applied to the antenna aperture surface, the null of the antenna side lobe decreases, and when a large phase distribution is applied, the antenna beam widens. Figure 2a shows the aperture amplitude distribution,
FIG. 2b is a diagram showing a quadratic system phase distribution. Figure 2c is a diagram showing the antenna pattern when the magnitude of the quadratic phase distribution, that is, the maximum phase amount β at the end of the antenna aperture, is changed, and the null of the side lobe is reduced and the antenna beam is The fact that it spreads is obvious to anyone who understands antennas.

In FIG. 2, A shows the aperture amplitude, B shows the antenna aperture plane, and C shows the phase of the secondary system.

FIG. 3 is a diagram showing an embodiment of the present invention, in which a phase correction amount storage circuit 18, an adder 19, and a switch 20 are simply installed in the beam scanning controller 10 of the conventional radar device shown in FIG. A simple configuration realizes a quadratic phase distribution on the antenna aperture surface, embeds nulls in the antenna side lobes and widely forms a beam pattern according to missile launch conditions and target tracking conditions. Missiles can be guided without horn antennas, flat horn antennas, combiners and switchers.
The phase correction amount storage circuit 18 stores secondary system phases on the antenna aperture plane for a large number of antenna elements for the case of filling the null of the antenna side lobe and the case of forming a wide beam pattern. Based on the beam scanning angle command signal a from the information processor 9, the phase amount calculation control circuit 11 calculates the amount of phase shift necessary for beam pointing for each antenna element. When the target is successfully tracked, the information processor 9 instructs the phase correction amount storage circuit 18 to send data for embedding the null of the antenna side lobe (instructs the secondary system phase data selection signal d), and launches the missile. In response to the signal, the information processor 9 outputs a switching signal c for connecting the adder 19 and the phase correction amount storage circuit 18 using the switching device 20 . The amount of phase shift and the amount of secondary phase correction for beam directing toward the target direction are added for each antenna element in an adder 19 and sent to the phased array antenna 4 through the drive circuit 12.
drive the phase shifter in the antenna element. When the target cannot be tracked, the information processor 9 sends the beam scanning angle command signal a to the phase shift amount calculation control circuit 11 with the beam scanning angle command signal a in front of the antenna, and when the missile is launched, the switch 20 uses a switching signal to change the phase to the adder 19 and the phase shift amount calculation control circuit 11. The phase shift amount calculation control circuit is connected to the correction amount storage circuit 18, instructs the phase correction amount storage circuit 18 to send out secondary phase correction data for forming a wide beam pattern, and uses an adder 19 to output the phase shift amount calculation control circuit for each antenna element. 11 and drives the phase shifter in the antenna element of the phased array antenna 4 through the drive circuit 12. Before the missile is launched, the switch 20 is grounded, so its terminal is always at zero and normal beam scanning is performed.

As described above, according to the present invention, a radar device that performs beam scanning electronically can be easily configured by simply installing a phase correction amount storage circuit, an adder, and a switch in a beam scanning controller. A quadratic phase distribution is provided on the antenna aperture surface, and depending on the missile launch situation and target tracking situation, it can be used to embed nulls in antenna side lobes without using a null-filling horn antenna, a flat horn antenna, a coupler or a switch. It becomes possible to form a wide beam pattern, allowing for good missile guidance.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of a conventional radar device, FIG. 2 is a diagram showing the effect of pattern forming used in the present invention, and FIG. 3 is a diagram showing an embodiment based on the present invention. Controller, 2 is a transmitter, 3 is a transmission/reception switch, 4 is a phased array antenna, 5 is a target, 6 is a receiver, 7 is a signal processor, 8 is an indicator,
9 is an information processor, 10 is a beam scanning controller, 11
12 is a phase shift calculation control circuit, 12 is a drive circuit, 13 is a missile, 14 is a coupler, 15 is a horn antenna, 16 is a switch, 17 is a horn antenna, 18
19 is an adder, 20 is a switch, β is a phase amount, Σ is a monopulse sum channel, and Δ is a monopulse difference channel. In the drawings, the same or corresponding parts are denoted by the same reference numerals.

Claims (1)

[Claims] 1. In a radar device that performs beam scanning electronically, a phase shift calculation control circuit that calculates the phase shift amount of a phase shifter of a large number of antenna elements constituting a phased array antenna, and a null embedding of an antenna side lobe. a phase correction amount storage circuit that stores the secondary system phase for each antenna element for forming a wide beam pattern; and an adder that adds the output of the phase shift amount calculation control circuit and the output of the phase correction amount storage circuit. , a switch for connecting and disconnecting the adder and the phase correction amount storage circuit, and a drive circuit for outputting the output of the adder to the phased array antenna, and changing the amplitude distribution on both sides of the antenna aperture. By providing a quadratic phase distribution, the nulls that occur in the antenna side lobes can be filled in, and the radar transmission radio waves necessary for missiles flying in the direction of the nulls of the side lobes can be sent out, and the antenna can be A radar device that forms a wide beam pattern and sends radar transmission radio waves to missiles and targets that fly within the beam pattern.