JPH02183191A - Tracing apparatus of many objects - Google Patents

Abstract

PURPOSE:To improve tracing accuracy and to reduce tracing time by changing the beam width in accordance with the distance to an object during tracing of said object. CONSTITUTION:A calculating circuit 8 calculates the suitable receiving width of beams for tracing an object from a predicting distance Rt of the object from a distance measuring circuit 5 and inputs the width to a beam orientation controller 7. The calculating circuit 8 calculates from the detected predicting distance Rt (output of the measuring circuit 5) the beam width thetaB corresponding to the predicting distance Rt by an equation such as D=2.Rt.tan(thetaB/2) so that the diameter D of the beam width is constant. The beam width thetaB can be obtained from an equation thetaB=2.tan<-1>(D/2Rt) when the value of the diameter D is set. The value of thetaB is input to the controller 7, where the phase data corresponding to the value thetaB is formed. The phase data is then output to a phased array antenna 1 to receive a reflecting wave from the tracing object by the beam width. Accordingly, as compared with the system whereby the reflecting wave from the tracing object is received by a constant beam width, the tracing object can be positively put in the beams.

Description

[Detailed Description of the Invention] [Field of Application] This invention relates to a multi-target tracking device equipped with a phased working array radar that simultaneously performs search and multi-target tracking by scanning a single beam. It is.

[Conventional technology]

Figure 4 shows a functional block diagram of a multi-target tracking device using a typical conventional phased array radar system. In Figure 1, (1) is a phased array antenna, (2) is a transmitter/receiver switch, (3) is a receiver, (4) is an angle measurement circuit, (5) is a distance measurement circuit, and (6) is a transmitter.

(7) is a beam direction suppressor.

A conventional multi-target tracking device using a phased array fist radar system is configured as described above, and the nine microwave power generated by the transmitter (6) is sent to the phased array antenna (1) via the transmitter/receiver switcher (2). ).

The phased array antenna (1) radiates this microwave power in the direction determined by the phase data of the beam direction control device (7), receives the reflected wave from the target, and uses the built-in monopulse antenna. A sum signal (distance signal) and a difference signal (angular error signal) are created by a comparator and inputted to a receiver (3) via a transmission/reception switch (2). Receiver 1
3) converts each of them into a video signal, and supplies the sum signal (distance signal) to the distance measuring circuit (5) and the difference signal (angular error signal) to the angle measuring circuit (4).

The angle measuring circuit (4) and the distance measuring circuit (5) calculate a target angle and a target distance, respectively, from the supplied signals.

Also, the search frame time (time required to search a predetermined space) T7 of such a multi-target tracking device is the sum of the time required for search Ts and the time required for target tracking Tt as shown in the following equation.

Ty ; Tg + Tt Tj is also the number of pulse hits n required for tracking as follows
and the number of tracking targets.

TI, ==N*na PR work [Problem to be solved by the invention] In the above-mentioned multi-target tracking device, when the target movement is large and the target approaches the neighbor @, it will be located at the outer button of the beam width. There was a problem that tracking was lost. (This is because the diameter of the beam width θB is proportional to the target distance Rf, and as the target approaches, the target movement width exceeds D. D=2・Rt・taa (θB/2)) In addition, when tracking is performed with a constant beam width, if the peripheral area is scanned at the ninth point without losing tracking, the search frame time TF becomes thicker due to the larger Tt.
This has the problem of not only increasing the system reaction time until target detection, but also reducing the maximum detection distance performance defined by the cumulative detection probability. (This is due to the fact that R(max) = -RQ・Ty 8. Here, R(maK) is the maximum detection distance defined by the cumulative detection probability, and RQ is the detection probability of 50%. This invention was made with the aim of improving this problem, and utilizes the feature of phased array radar that the beam width can be arbitrarily set by phase control, and uses The purpose of this invention is to obtain a system that improves tracking accuracy and reduces tracking time Tt (prevents increase in search frame time TF) by controlling the beam width during tracking.

CII! ! As a precautionary measure to solve the problem, the multi-target tracking device according to the present invention is equipped with a "transmission/reception beam width calculation circuit" that calculates an appropriate value of the transmission and reception beam width according to the target distance. It is something.

In addition, in order to prevent the transmitting antenna gain G from deteriorating, a "receiving beam width calculation circuit" is installed that calculates only the receiving beam width according to the target distance.

(This is because the antenna gain G is inversely proportional to the square of the beam width θB, and the tracking accuracy is inversely proportional to β.) [Operation] In this invention, target tracking is performed using a constant beam width. Unlike conventional tracking methods, the beam width is changed according to the target distance to track the target, which not only prevents loss of tracking when the target movement is large or the angle measurement error of the target is large. Since the antenna gain G is controlled by changing the beam width, tracking accuracy can be kept constant. (This is because the tracking accuracy is proportional to Rt2/β and it is possible to keep Ht2/β constant.) Also, beam scanning of one peripheral area is not required.

It is possible to prevent a significant increase in search frame time due to tracking.

〔Example〕

FIG. 1 shows an embodiment of the present invention.

(1) to (7) are exactly the same as the conventional device described above, (8) is a receiving beam paddle calculation circuit, and a distance measuring circuit (5) is the receiving beam paddle calculation circuit.
), a beam width for optical reception suitable for tracking the target 5 is calculated and input to the beam direction controller (7).

In the multi-target tracking device configured as described above, the predicted target distance Rt (ranging circuit (5)
), the receiving beam width calculating circuit (8) calculates the beam width θB corresponding to the predicted target distance Fj1; Ic using the following equation so that the diameter of the beam width is constant.

D=21IRte-(θB/2) (3
1 If the value of D is determined here, θB becomes the following equation.

θB=2 ・--' (!)/2 Rt)
14) This θB is output to the beam directivity controller (7), which creates phase data corresponding to θB, and outputs it to the phased array antenna (1) to detect the distance from the tracking target. Receive the reflected wave with that beam width.

Therefore, the reflected wave from the tracking target is received with a constant beam width.
Compared to conventional methods, it is possible to reliably place the tracked target within the beam.

Taking this situation as an example when the target approaches from a long distance,
@ Shown in Figure 2.

In FIG. 2, 17) shows tracking with a constant beam width in the conventional method, (a) is a cross-sectional view thereof, (1) is tracking with a variable beam width in the present invention, and (b) is a cross-sectional view, (a)
is the beam width when the distance is Rt1, (b) is the movement width of the target in the angular direction, (C) is the diameter of the beam width (a) when the distance is Rt1, and (d) is the beam @ (a) when the distance is Rt2. diameter, (e
) is the beam width in the present invention at the distance 11)lRt2.

Furthermore, since the pulse repetition period can be set to correspond to the target distance, FIG. 2 also explains how the tracking time can be shortened.

Note that in the above embodiment, the beam width is calculated according to the target distance to prevent a significant increase in the search frame time due to tracking, but target tracking is performed by changing the number of pulse hits according to the target distance. Therefore, similar behavior can be expected.

FIG. 3 shows another embodiment of the present invention, (1
) to (8) are exactly the same as in the above embodiment.

(9) is a transmission beam width calculation circuit, and distance measuring circuit (5)
Based on the predicted distance of the target from the target, a transmission beam width suitable for tracking the target is calculated and input to the beam direction controller (7).

In the multi-target tracking device configured as described above, the predicted distance Rf of nine targets detected by search, (ranging circuit (
From the output of 5), the transmission beam width calculation circuit (9) calculates the target predicted distance f! as shown in the following formula so that the diameter of the beam width is constant even during transmission. Calculate the beam width θB corresponding to fleRt.

θB=2・tm-' (D/2Rt)
(5) Output this θB to the beam direction controller (7), create phase data corresponding to θB in the beam direction controller (71), and output it to the phased array antenna (1) K to the tracking target. Transmission and reception are performed using that beam width.

Therefore, compared to the conventional system in which the beam is transmitted to and received from the tracking target using a constant beam width, it is possible to reliably place the tracking target within the beam.

〔Effect of the invention〕

As explained above, the present invention adds a mechanism that calculates the beam width corresponding to the predicted target distance to perform target tracking by changing the beam width according to the target tracking distance. This not only prevents tracking from being lost when the angle measurement error of the target is large, but also controls the antenna gain G by changing the beam width, which has the effect of keeping the tracking accuracy constant.

[Brief explanation of the drawing]

FIG. 1 is a system block diagram showing an embodiment of the present invention;
FIG. 2 is the ninth diagram for explaining its function and effect, FIG. 3 is a system block diagram showing another embodiment of the present invention, and FIG.
The figure is a system block diagram of a conventional multi-target tracking device. In the figure, f1+ is a phased array antenna (2
) is the transmitter/receiver switch, (3) is the receiver, (4) is the angle measurement enclosure,
(5) is a ranging circuit, (6) is a transmitter, and (7) is a beam direction controller. (8) is a receive beam width calculation circuit, (9) is a transmission beam width calculation circuit, (a) is the beam width at distance @ Rt1, (b) is the movement width of the target in the angular direction, (C) is the distance Rt1 (a) is the diameter of the beam width at the time, (d) is the beam width f at the time of the distance Rt2.
(a) is the diameter, and (e) is the beam width in the present invention at distance Rt2. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (2)

[Claims] (1) A phased array antenna equipped with a phase shifter that controls the phase of the element antenna, and the received signal received by this phased array antenna is input through a receiver, and the signal is transmitted from the received signal to the target. A multi-target tracking device comprising: a distance measuring circuit for measuring the distance; and means for calculating a receiving beam width according to the target distance using distance information obtained by the distance measuring circuit. . (2) A phased array antenna equipped with a phase shifter that controls the phase of the element antenna, and the received signal received by this phased array antenna is input through a receiver, and the signal is transmitted from the received signal to the target. and means for calculating a transmitting/receiving beam width according to the target distance using the distance information obtained by the distance measuring circuit. Target tracking device.