JPH0213752B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radar device that automatically acquires and tracks a target using a monopulse type phased array antenna that has the function of forming a fan beam and a pencil beam.・By utilizing the beam forming function of the array antenna, the antenna beam scanning function and beam shape switching function synchronized with target detection, and the target angle error detection function of the monopulse tracking radar, the search time for the target is reduced. The present invention also relates to a radar device aimed at shortening acquisition time.

First, a target acquisition and tracking method in this type of radar apparatus using a conventional mechanically driven monopulse antenna will be explained with reference to the drawings.

FIG. 1 is a diagram showing an antenna scanning method in a conventional radar device of this type.

During a search, the antenna is scanned along a search antenna scanning pattern 3 that completely covers the search area 2 with a pencil beam 1 having an antenna beam width of θ _B. Now, the antenna has an azimuth θ _AZ ,
The antenna scanning pattern ₅ at the time of acquisition covers an area where the presence of the target is probabilistically predicted (hereinafter referred to as the "target existence area") when the target is detected by scanning the vicinity of the target direction 4 with an elevation angle θEL. The antenna scans along the path and shifts to monopulse tracking. Therefore, in order to acquire the target and shift to monopulse tracking, the search area 2 must be covered with a narrow pencil beam 1.
The search time required for scanning with the pencil beam 1 and the acquisition time required for scanning the target area with the pencil beam 1 after detecting the target are required.

By the way, in a tracking radar, it is essential to shorten the search time and acquisition time mentioned above in order to quickly acquire a target. , it would be better to narrow the target area by further increasing the accuracy of target indication during the search.
Adding a function to switch the shape of the antenna beam to this type of radar equipment that uses a conventional mechanically driven monopulse antenna requires a hard
Furthermore, since target detection and antenna scanning are independent, it is usually not possible to narrow the target area to less than 2 to 4 times the antenna beam width during search. It was hot.

This invention aims to improve the above-mentioned drawbacks, and has the function of shaping a fan beam with a wide beam width for quickly scanning a predetermined search area and a Vencil beam for tracking. A monopulse type phased array antenna is used to perform beam scanning in synchronization with target detection, and when a target is detected during a search using the fan beam, the pencil beam is sent in the direction of the target obtained using the monopulse principle. It is an object of the present invention to provide a radar device that can shorten the search time and acquisition time by directing the beam and shifting to monopulse tracking.

This will be explained in detail below using FIGS. 2 and 3.

FIG. 2 is a block diagram showing an embodiment of the present invention, and FIG. 3 is a diagram showing the antenna beam scanning method of the present invention. In Figures 2 and 3,
A high frequency pulse signal generated by the transmitter 6 is radiated to the outside space via the transmitter/receiver switch 7 and the phased array antenna 8. On the other hand, the signal received by the phased array antenna 8 on the sum channel is inputted to the sum channel receiver 9 via the transmission/reception switch 7, amplified, and inputted to the signal processor 10 and the divider 11. Also, phased array
The received signal on the difference channel of the antenna 8 is input to the difference channel receiver 12, amplified, and input to the divider 11. The divider 11 calculates the ratio between the output of the receiver 9 for the sum channel and the output of the receiver 12 for the difference channel, and inputs the ratio to the signal processor 10. Note that the received signal of the difference channel includes azimuth angle and elevation angle signals in a time-division manner.

Now, when the radar device 13 of the present invention is in a search state, when the signal processor 10 processes the output signal of the receiver 9 of the sum channel and determines that there is no target, the beam forming controller 14 and the beam scanning control The controller 15 is commanded to continue the search state. At this time, the beam shaping controller 14 controls the phased array antenna 8 so as to continue shaping the fan beam, and the beam scanning controller 15 controls the phased array antenna 8 so as to change the beam directivity angle by θ _S. By repeating such operations, beam scanning is performed with the fan beam 16 along a beam scanning pattern 17 that completely covers the search area 2.

Now, when the Juan beam 16 is directed at the azimuth angle θ _SA and the elevation angle θ _SE , the signal processor 10 detects the target from the output of the receiver 9 of the sum channel, and from the output of the divider 11 at that time. When the angle errors Δθ _AZ and Δθ _EL of the target are detected by the monopulse principle, a command is given to the beam forming controller 14 and the beam scanning controller 15 to perform antenna control in the acquisition state. This command causes the beam shaping controller 14 to switch the beam shape to a pencil beam 1 with a beam width of θ _B , and the beam scanning controller 1
5 is the beam directivity angle when the target is detected.The target is the azimuth angle θ AZ and the elevation angle θ _EL given by the above azimuth angle θ _SA , elevation angle θ _SE and the above angular errors Δθ _{AZ and} Δθ _EL . The phased array antenna 8 is controlled so as to direct the pencil beam 1 in the direction 4, and the transition is made to monopulse tracking.

As described above, according to the present invention, when a target is detected by searching with a fan beam having a wide beam width, a tracking pencil is set in the target direction given by the beam directivity angle at that time and the angular error of the target.
By directing the beam, the search time and acquisition time for a target can be shortened.

Although FIG. 2 shows a configuration example and FIG. 3 shows an antenna beam scanning method as an embodiment of the invention, various modifications can be made without departing from the gist of the invention.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an antenna scanning method in a conventional radar device, FIG. 2 is a block diagram showing an embodiment of the present invention, and FIG. 3 is a diagram showing an antenna beam scanning method of the present invention. In the figure, 1 is the pencil beam, 2 is the search area, 3 is the antenna scanning pattern during search, 4 is the target direction, 5 is the antenna scanning pattern during acquisition, 6 is the transmitter, 7 is the transmitter/receiver switch, and 8 is the transmitter/receiver switch. Phased array antenna, 9
is a Japanese channel receiver, 10 is a signal processor, 1
1 is a divider, 12 is a difference channel receiver, 13
14 is a beam forming controller, 15 is a beam scanning controller, 16 is a fan beam, and 17 is a beam scanning pattern. In addition,
In the figures, the same or corresponding parts are designated by the same numbers.

Claims (1)

[Claims] 1 Automatically captures and tracks targets using a monopulse phased array antenna that has the function of forming a fan beam for quickly scanning a predetermined search area and a pencil beam for tracking. In the radar device configured as above, means for performing antenna beam scanning in synchronization with target detection and switching between the fan beam and the pencil beam, and a sum channel and a difference channel of the monopulse type phased array antenna. It is equipped with a receiver provided corresponding to each of the two receivers, and a divider that calculates the ratio of the outputs of the respective receivers, and when a target is detected during a search using the fan beam, the beam shape is automatically changed. A radar device characterized in that the radar device is configured to switch, direct the pencil beam in a target direction given by the output signal of the divider, and shift to monopulse tracking.