JPH0213753B2 - - 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 data storage circuit for fan beam formation, and an adder. The fan beam is scanned at high speed by driving and controlling the phase shifter of the phased array antenna, and when a target is detected by a signal processor, the beam is fixed in that direction. Then, using the monopulse difference channel in the wide beam width direction of the Fan beam, an angular error signal indicating the direction of the target is obtained, and the information processor switches the Fan beam to a pencil beam and directs it to the target direction to track the target. By doing so, the present invention aims to provide a radar device that can search for a target from a wide angular range and greatly shorten the time required to capture and track a target.

Conventional radar devices using phased array antennas or mechanical scanning antennas have the disadvantage that it takes a long time to scan the entire angular range because the pencil beam scans a wide angular range. In addition, in the case of mechanical scanning antennas, it is difficult to change the antenna beam shape, and even if the signal processor detects a target, the beam cannot be instantly fixed in the target direction due to the inertia of the antenna. , scan the antenna beam over a narrow angular range in the target direction,
Because it uses means to capture and track the target, it takes even longer.

Generally, during close combat of fighter aircraft, radar equipment for fighter aircraft is required to detect, capture, and track targets at relatively short distances in a short time rather than detecting targets at long distances. . Therefore, the length of time it takes to search for and acquire a target determines the target attack ability and survivability of a fighter aircraft. This will reduce the performance of the machine.

This invention was made in order to eliminate such drawbacks in conventional radar equipment, and it provides a beam scanning controller for original beam scanning with a phase data storage circuit, an adder, and a switch. It is possible to easily form a fan beam with a simple configuration that only controls these, and when this fan beam is scanned at high speed and the information processor fixes the fan beam using the target detection signal from the signal processor. , the signal processor extracts the error signal of the monopulse difference channel and sends out an angle signal in the wide beam width direction of the fan beam, so the information processor switches the fan beam to a pencil beam and directs it to the target direction. The present invention aims to provide a radar device that can significantly shorten the time it takes to search for, acquire, and track a target located at a relatively short distance by capturing and tracking a target.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A conventional radar device and a radar device of the present invention will be explained below with reference to the drawings. FIG. 1 is a diagram showing an example of the configuration of a conventional radar device, in which 1 is a controller, 2 is a transmitter, 3 is a transmitter/receiver switch, 4 is a phased array antenna, 5 is a receiver, and 6 is a signal processor, 7 is a display, 8 is an information processor, 9 is a beam scanning controller, 10 is a phase shift calculation control circuit, 11 is a drive circuit, Σ is a monopulse sum channel, and △ is a monopulse difference channel. .

Since the configuration of the conventional radar device described above is as described above, the transmitter 2 transmits a pulsed transmission signal to the phased array antenna through the transmission/reception switch 3 based on the radar transmission mode selected by the control unit 1. Send to 4. The transmitted signal is radiated into space from the phased array antenna 4, reflected by the target, received by the phased array antenna 4 again, and inputted again to the receiver 5 through the transmitter/receiver switch 3. This received signal is amplified and mixed by the receiver 5 to become an intermediate frequency band signal, which is further amplified and then detected, converted into a digital signal, and sent to the signal processor 6. The signal processor 6 performs processing such as detection of the digitally converted video signal, and when it is determined and detected as a signal, the information is sent to the display 7 for display. The output of the signal processor 6 is also sent to the information processor 8, where it undergoes target tracking processing based on the target tracking command from the controller 1, extracts accurate distance, speed, and angle information, and provides instructions. It is displayed on the container 7 with symbols and numbers.

On the other hand, when the information processor 8 sends the beam scanning angle command signal a to the phase shift amount calculation control circuit 10 in the beam scanning controller 9 based on the coverage area and beam scanning pattern selected by the controller, the phase shift amount calculation is performed. Control circuit 1
0 calculates the amount of phase shift to be applied to the phase shifters of a large number of antenna elements (not shown) constituting the phased array antenna, outputs a phase shifter drive signal b from the drive circuit 11, and shifts the phase of the antenna elements. Set the device to drive. As a result, the antenna main beam is directed in the command angle direction.

Furthermore, in order to fire weapons such as missiles at targets from a long distance, fighter jet radars are required to discover, capture, and track targets at long distances, but in this case, a high-gain pencil beam is used. Scanning at a relatively slow speed is advantageous because the data rate is higher and targets can be detected over longer distances. On the other hand, when fighter jets engage in close combat, the distance to the target is short, so they fire short-range weapons such as machine guns, so they are required to spot, capture, and track the target faster than the enemy. However, since conventional radars scan with a pencil beam, it takes a long time to scan a wide angular range. In close combat, the distance to the target is short, so the signal reflected from the target has sufficient strength, and sufficient target detection performance can be ensured even if a fan beam with reduced gain is used. Since the angular range is expanded when a fan beam is used, the time required to scan a wide angular range can be reduced compared to when a pencil beam is used.

Figure 2a shows the beam scanning method of a conventional radar device, and the time T _P required to scan the entire angular range with the pencil beam 15 is T _P = θ _AZ θ _EL /ωθ _BP θ _AZ : Horizontal scanning Angle range θ _EL : Vertical scanning angle range ω: Beam scanning speed θ _BP : Beam width of the pencil beam, and the average time required to find the target is
T _P /2. FIG. 2b shows a beam scanning system of a radar device based on the present invention, in which the pencil beam 15 is directed in the target direction by scanning the entire angular range of the fan beam 16 and obtaining an angular error signal using a monopulse difference channel. The time required to _{do this is T F =θ AZ θ EL /ωθ BF + T M = 1} /Nθ _AZ θ _EL /ωθ _BP +
T _M = T _P /N + T _M θ _BF : Beam width of the Fan beam T _M : Time required to obtain an angular error signal in the monopulse difference channel N: Ratio of beam widths of the Fan beam and the pencil beam N = θ _BF / θ _BP . The average time it takes to discover a target is
(T _P /2N+T _M ).

As is clear from this equation, the fan beam 16
By scanning with , the time required to move from target detection to acquisition and tracking can be significantly shortened.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 3 is a diagram showing an embodiment of this invention,
The feature of the present invention is that it has a simple configuration in which a phase data storage circuit 12, an adder 13, and a switch 14 are installed in the beam scanning controller 9 of the conventional radar device shown in FIG. When a target is found by scanning a wide angular range with the fan beam, the beam is fixed, the monopulse difference channel is used to obtain the angular error signal d, and the pencil is moved in the direction of the target. It is possible to direct the beam and capture and track the target in a short period of time. The phase data storage circuit 12 stores phase distributions on the antenna aperture plane necessary for forming a fan beam corresponding to a large number of antenna elements.
Based on the beam scanning angle command signal a from the information processor 8, the phase shift calculation control circuit 10 calculates the phase shift amount of each antenna element necessary to direct the beam in the commanded direction. Now, when the short-range target automatic acquisition mode is selected by the controller 1, the information processor 8 receives the mode signal from the controller 1, and transmits the beam shape switching signal e to the switch 14 in the beam scanning controller 9. Send to. The switch 14 receives the beam shape switching signal e and connects the phase shift calculation control circuit 10 and the adder 13. The information processor 8 is the switch 1
4, when the beam scanning angle command signal a is sent to the phase shift calculation control circuit 10, the phase shift calculation control circuit 10 calculates the phase shift amount of each antenna element necessary for beam scanning in the command direction. is calculated and sent to the adder 13 for each antenna element. Adder 1
3 adds the phase shift amount of each antenna element from the phase shift calculation control circuit 10 and the phase data for fan beam formation sent from the phase data storage circuit 12 through the switch 14 for each antenna element and drives the antenna element. The signal is sent to the circuit 11. The drive circuit 11 drives and controls a phase shifter of an antenna element (not shown) of the phased array antenna 4. At the antenna aperture plane, a curved phase distribution for fan beam formation is added and synthesized on a linear phase plane according to the beam directivity angle, so a fan beam is formed in the direction of the beam scanning angle. . The information processor 8 sequentially updates the beam scanning angle command signal a to change the beam pointing angle in order to scan the fan beam over a wide angle range.

On the other hand, in response to the mode signal from the controller 1, the transmitter 2 generates a pulsed transmission signal and sends it to the phased array antenna 4 through the transmitter/receiver switch 3.
The transmitted signal is radiated into a wide space as a fan beam from the phased array antenna 4, and when a target exists within the fan beam, it is reflected and received by the phased array antenna 4, and then passes through the transmitter/receiver switch 3 again and is sent to the receiver 5. The signal is input to the signal processor 6 as a video signal that is amplified, mixed, and converted into a digital signal. The signal processor 6 is the receiver 5
The target signal is detected from thermal noise generated by the ground or clutter reflected from the ground and received at the same time as the target signal. In the case of the pulse radar method, the received signal is envelope-detected, so the magnitude of the amplitude of the pulsed signal and its delay time from the transmitted pulse is determined, and in the case of the pulsed Doppler radar method, the received signal is detected by phase detection. Therefore, the Doppler frequency information and the uncertain delay time from the transmitted pulse are determined. When the signal processor 6 detects the target signal as distance information, it sends it to the display 7 for display, and at the same time sends the target detection signal c to the information processor 8.
The information processor 8 receives the target detection signal c from the signal processor 6.
When received, the beam scanning angle command signal a is held at the angle signal in the direction in which the fan beam detects the target, and at the same time, the signal processor 6 is caused to execute signal processing of the monopulse difference channel. The signal processor 6 is
The magnitude and phase of the monopulse sum channel signal and the monopulse difference channel signal are detected, and an angular error signal d is transmitted to the information processor 8. When the information processor 8 receives the angle error signal d, it generates a beam shape switching signal e.
is sent to the switch 14 in the beam scanning controller 9 to switch the fan beam to the pencil beam. At the same time, the angular direction according to the angular error signal d is calculated, and the beam scan is performed to direct the pencil beam in that direction. The angle command signal a is sent to the phase shift amount calculation control circuit 10 as angle information in the target direction. When the switch 14 receives the beam shape switching signal e, it disconnects the phase data storage circuit 12 and connects it to the ground terminal, so the output from the switch 14 to the adder 13 is always zero. Then, the output signal of the phase shift calculation control circuit 10 is added to zero in the adder 13, and is passed through the drive circuit as it is to drive and control the phase shifters of the many antenna elements of the phased array antenna.

Therefore, since the aperture plane phase distribution for fan beam formation is removed, the beam becomes a normal pencil beam, and the pencil beam is directed toward the target by the beam scanning angle command signal a in the direction where the target exists. The signal received by the pencil beam is subjected to monopulse processing by a receiver 5 and a signal processor 6, and an angular error signal d is sent to an information processor 8 for precise angular tracking. The information processor 8 detects the difference between this angle error signal d and the beam scanning angle command signal a, and updates the beam scanning angle command signal a so that this difference becomes zero, so that the target can be captured and tracked. .

As described above, according to the present invention, in a radar device that electronically scans a beam, the antenna aperture can be By easily forming and scanning a fan beam by switching the phase distribution of the target, the time required from searching for a nearby target to acquiring and tracking it can be significantly shortened.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of a conventional radar device, FIG. 2 is a diagram showing a beam scanning method of a conventional radar device and a radar device based on the present invention, and FIG. 3 is a diagram showing an embodiment of the radar device based on the present invention. It is a diagram showing the configuration of the device, in which 1 is a controller, 2 is a transmitter, 3 is a transmission/reception switch, 4 is a phased array antenna, 5 is a receiver, 6 is a signal processor, 7 is a display device, and 8 is a Information processor, 9 beam scanning controller, 10 phase shift calculation control circuit, 11 drive circuit, 12 phase data storage circuit, 13 adder, 14 switch, 15 pencil beam, 16 fan beam, a is a beam scanning angle command signal, b is a phase shifter drive signal, c is a target detection signal, d is an angle error signal, e is a beam shape switching signal, Σ is a monopulse sum channel, △ is a monopulse difference channel, T _P is the scanning time by the pencil beam, T _F is the scanning time by the fan beam,
θ _AZ is the horizontal scan angle range, θ _EL is the vertical scan angle range, θ _BP is the beam width of the pencil beam,
θ _BF is the beam width of the fan beam, ω is the beam scanning speed, N is the ratio of the beam widths of the fan beam and the pencil beam, and T _M is the time required to obtain the angular error signal in the monopulse difference channel. Note that the same or corresponding parts in the figures 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 the phase shifter of a large number of antenna elements constituting a phased array antenna, and a fan beam that is a phase data storage circuit that stores phase data for forming the phase data; an adder that adds the output of the phase shift amount calculation control circuit and the output of the phase data storage circuit; the adder and the phase data storage circuit; a beam scanning controller for controlling the phase shifters of the plurality of antenna elements; and a beam scanning controller for controlling the phase shifters of the plurality of antenna elements; a signal processor that simultaneously processes a monopulse difference channel and a monopulse sum channel in which the beam of the Fan beam has a wide range of directions, detects a target signal in the sum channel, and obtains an angular error signal indicating the direction of the target in the difference channel; Upon receiving the visual detection signal from the processor, a beam shape switching signal is generated to the switch, the input of the adder is set to zero, the fan beam is switched to the pencil beam, and the angular error signal from the signal processor is output. an information processor that calculates a beam directing angle for directing the pencil beam in the target direction based on the above information and generates a beam scanning angle command signal to the phase shift amount calculation control circuit; A fan beam is formed by giving phase data for beam scanning from the above and phase data for fan beam formation from the phase data storage circuit, and this is scanned at high speed to search for a target in a wide angular range in a short time. When a target is detected,
Fix the Fan beam there, calculate the wide beam direction angle of the Fan beam based on the angular error signal of the monopulse difference channel, and separate the adder from the phase data storage circuit to form a pencil beam and point it in that direction. A radar device characterized by rapidly tracking a target.