JPH02216489A - Radar equipment - Google Patents

Abstract

PURPOSE:To shorten the time for measuring the azimuth and the elevation angle of a target by changing a beam scanning system by the use of a fan beam in a beam controller and shortening a PRI by a timing generating device. CONSTITUTION:A radar equipment has a constitution that the fan beam 8 is formed so that the beam scanning may be performed in the azimuth direction by the beam controller 7. And when the target is detected by a signal processor 5, a distance to the target is measured and the distance information is given to the timing generating device 6 by the signal processor 5 at once. And then the measurement of the elevation angle of the target is performed on a phase 2. In the timing generating device 6 having the distance information, a PRI is changed to the PRIEL, shown by an expression I. By comparing the PRIAZ which is used at the time of measuring the azimuth with the PRIEL which is used at the time of measuring the elevation angle, PRIEL <= PRIAZ is realized because of R (detected distance) 1 <= R max (maximum detected distance). Thus, the time for measuring can be shortened by changing the PRI to the short PRIEL so as to transmit.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a radar device that reduces the time required to measure the azimuth and elevation angle of a target.

[Conventional technology]

FIG. 4 is a diagram showing the configuration of a conventional radar equipment. In the figure, (1) is a transmitter, and (2) is a transmitter/receiver switch.

(12) is a mechanically driven antenna with sharp unidirectionality (hereinafter referred to as a pencil beam), (4) is a receiver, (5) is a signal processor, and (13) is an antenna (12) that is mechanically driven. Next, the operation of the antenna driver for rotating the antenna in the beam pointing direction will be explained. A transmitter (1) generates a transmission pulse with a constant pulse repetition period (hereinafter referred to as PRI), and transmits it to the antenna (2) via a transmitter/receiver switch (2).
This PRI transmitted from 12) to the external space is expressed by equation (1)
This is the value required to detect a target at the maximum distance shown in .

PRI-2R@ax/C+ a --
--= (1) where R■ax: maximum detection distance C: speed of light α: margin time FIG. 5 is a diagram showing beam scanning controlled by the antenna driver (13). As shown in the figure, the pencil beam (9) is sequentially scanned from the top to the left and right, then down to the left and right. Note that the beam scanning speed is expressed by the formula %, where ω: Beam scanning speed θ8: Beam width n: Pulse integral number PRI: Pulse repetition period given by formula (1) This pulse integral number n determines the target at the maximum detection distance. This is the number of pulse integrations required for detection. In this way, the elevation angle and azimuth angle are measured from the beam direction when the target is detected.

[Problem to be solved by the invention]

Conventional radar equipment is configured as described above, so
The desired search area must be scanned with a narrow pencil beam and P corresponding to the maximum target distance of interest.
Since the beam is transmitted by RI, beam scanning becomes slow as shown in equation (2), and the time required to measure the elevation angle and azimuth of the target becomes longer. In addition, signal processing must be performed using the number of pulse integrations necessary to detect a target at the maximum distance, which slows down the beam scanning as shown in equation (2), and changes the height angle of the target. There was a problem in that it took a long time to measure the azimuth angle.

This invention was made to solve the above problems, and by changing the beam shape and shortening the PRI to speed up beam scanning, it is possible to shorten the time required to measure the elevation angle and azimuth of the target. The purpose is to obtain radar equipment. Another invention of the present invention is to obtain a radar device that can further shorten the time for measuring the elevation angle and azimuth angle of a target by reducing the number of pulse integrations and increasing the speed of beam scanning in addition to the above-mentioned means. purpose.

[Means to solve the problem]

The radar device according to the present invention includes a beam controller that switches the beam shape from a beam that is wide in the elevation angle direction and narrow in the azimuth direction (hereinafter referred to as a fan beam) to a pencil beam, and a timing generator that changes the PRI. It was established.

A radar device according to another aspect of the present invention includes the above means!
In addition, an integral number controller is provided to change the pulse integral number.

[Effect]

In this invention, when a beam controller forms a fan beam and scans the beam in the azimuth direction to detect a target, the signal processor measures the distance to the target and provides it to the timing generator as distance information. The timing generator changes PRl according to this distance information, and the beam controller switches to a pencil beam and scans the beam in the elevation angle direction, thereby reducing the time required to measure the elevation angle and azimuth of the target.

In another invention of the present invention, in addition to the above-mentioned effects, when a fan beam is formed and a target is detected, the signal processor also provides distance information to the integral number controller, and the integral number controller determines the distance. The time required to measure the elevation angle and azimuth of the target can be shortened by changing the number of pulse integrals according to the information, and by switching to a pencil beam using the beam controller and scanning the beam in the elevation angle direction.

〔Example〕

FIG. 1 is a diagram showing the configuration of a radar device according to the present invention. In the figure, (1) is a transmitter, (2) is a transmitter/receiver switch, (3) is a phased array antenna, and (4) is a receiver.

(5) is a signal processor, (6) is a timing generator connected to the signal processor (5), and (7) is a beam controller connected to the phased array antenna (3) to control the beam. be.

Next, the operation will be explained. The method of measuring the elevation angle and azimuth angle of a target in the present invention is divided into two phases: one is the measurement of the azimuth angle of the target, and the other is the measurement of the elevation angle of the target. To explain the method of measuring the azimuth direction of the target, Fig. 2 shows a beam scanning method.
A fan beam (8) is formed by a beam controller (7) and the beam is scanned in the azimuth direction. PRI at this time
is the value required to detect the target at maximum distance.

This value is the same as the PRI transmitted by conventional radar equipment, and is referred to as PRIAz. When the signal processor (5) detects the target, the target distance is measured and the signal processor (5) immediately detects the target.
5) provides distance information to the timing generator (6). Also, in synchronization with this, the beam scan is stopped in that azimuth direction,
A command is sent to the beam controller (7) to switch to the pencil beam (9) and scan the beam in the height angle direction.

Then, we move on to phase 2, which is measurement of the height angle of the target. The timing generator (6) given the distance information is expressed as Equation (3)
Change PRl to L as shown in .

PRIK i, = 2R/c+α・
...(3) However, R: Detection distance C: Speed of light α: Margin time Here, let's compare PRIA□, which is used to measure the azimuth angle, and PR1, L, which is used to measure the elevation angle. Since R (detection distance)≦Rwax (maximum detection #), PRI−g t,≦PRIA.

holds true. In this way, by changing to shorter PRl and L and transmitting, the time can be shortened, and Equation 2 (2)
In addition, in synchronization with changing the PRI, the beam controller (7) switches the beam shape from a fan beam (8) to a pencil beam (9), and scans the beam in the vertical direction. The phased array antenna (3) is controlled so that the In this way, the goal (
10) By measuring the beam direction at the time of detection, the elevation angle and azimuth of the target can be measured. It is possible to measure angles.

Next, FIG. 3 is a diagram showing the configuration of a radar device according to another embodiment of the present invention. This radar device is (1) to (7)
) is completely the same as the configuration of the radar apparatus of the present invention described above, and an integral number controller (11) for changing the number of pulse integrals is connected to the signal processor (5).

To explain the operation, in addition to the method of the radar device described above, when measuring the elevation angle of the target (phase 2), signal processing is performed by changing the number of pulse integrations. The number of pulse integrals during beam scanning in the azimuth direction (phase I) is the value required to detect a target at the maximum distance, and is different from the number of pulse integrals used for signal processing in conventional radar equipment. nA at the same value
Let it be Z. When a target is detected by the signal processor (5), the target distance is measured, and the signal processor (5) immediately provides distance information to the integral number controller (11).

Then, we move on to phase 2, which is measurement of the height angle of the target. The integral number controller (11) given the distance information changes the pulse integral number n11L according to the distance. Comparing the number of pulse integrals nA□ used when measuring the azimuth angle and the number of pulse integrals ngL used when measuring the elevation angle, we find that the pulses necessary to obtain the signal-to-noise power ratio required for target detection are The number of integrals increases in proportion to the fourth power of the distance, and the relationship between target distances for measuring azimuth angle and elevation angle is R (detection distance) ≦ Rmax (maximum detection distance). ngc, ≦nAz holds true. In this way, by performing signal processing instead of using a small number of ngL, beam scanning can be accelerated as shown in equation (2), and one hour can be shortened. Also, the beam controller (7) changes the beam shape to the fan beam (8).
The phased array antenna (3) is then switched to the pencil beam (9) and controlled to scan the beam in the height angle direction. By measuring the beam direction when the target (10) is detected in this way, the elevation angle and azimuth angle of the target can be measured, and the beam also scans once in each of the azimuth and elevation directions. It is possible to measure the elevation and azimuth angle of the target.

〔Effect of the invention〕

As described above, according to the present invention, the beam controller uses a fan beam to change the beam scanning method, and the timing generator shortens PRr, thereby reducing the time required to measure the azimuth and elevation angle of the target. There is.

In addition to the above-mentioned effects, another invention of the present invention has the effect of shortening the measurement time of the target azimuth and elevation angle by reducing the number of integrals using the integral number controller.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a radar device according to an embodiment of the present invention, FIG. 2 is a diagram showing a beam scanning method of the present invention, FIG. 3 is a block diagram of a radar device according to another embodiment of the present invention, and FIG. FIG. 4 is a block diagram of a conventional radar device, and FIG. 5 is a diagram showing a conventional beam scanning system. In the figure, (1) is the transmitter, (2) is the transmitter/receiver switch, and (3) is the transmitter.
) is a phased array antenna, (4) is a receiver, (5
) is a signal processor, (6) is a timing generator, (7) is a beam generator, (g) is a fan beam, (9) is a pencil beam, (10) is a target, (11) is an integral number switch, (12) The antenna (13) is an antenna driver. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (2)

[Claims] (1) A radar device that measures the azimuth and elevation angle of a target using a phased array antenna, which includes a beam controller that controls the beam shape and beam scanning speed of the phased array antenna, and a pulse repetition period according to the target distance. What is claimed is: 1. A radar device comprising a timing generator capable of changing the beam shape, beam scanning speed, and pulse repetition period, and configured to change the beam shape, beam scanning speed, and pulse repetition period in synchronization with target detection. (2) A radar device that measures the azimuth and elevation angle of a target using a phased array antenna, which includes a beam controller that controls the beam shape and beam scanning speed of the phased array antenna, and a pulse repetition period according to the target distance. It is equipped with a timing generator that can change the number of pulse integrals according to the target distance, and an integral number controller that can change the number of pulse integrals according to the target distance. A radar device characterized in that it is configured to perform operations synchronously.