JPH01227979A - Radar equipment - Google Patents

Abstract

PURPOSE:To prevent reduction in the search covering area of radar equipment due to target tracking operations and, at the same time, to improve the tracking accuracy of the equipment by maintaining a desired search covering area and searching targets by using a searching beam spot array which is changed in accordance with the number of the targets. CONSTITUTION:A beam spot number calculating circuit 9 calculates the number of beam spots searchable within an assigned searching time and inputs the calculated number to a searching beam coordinate calculating circuit 10. The circuit 10 calculates arraying intervals and positional coordinates of the beam spots from the searching beam spot number to a search covering area and outputs the calculated results to a beam scanning sequence circuit 7. The circuit 7 forms a searching sequence for searching the search covering area and, at the same time, outputs a beam orienting direction to an antenna drive controller 8 and transmits transmitting information to a transmitter 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a radar device that can perform both a search function and a tracking function at the same time.

[Conventional technology]

Figure 3 shows a functional block diagram of a typical conventional radar device. (5) is a target detection circuit.

(6) is a target tracking circuit, (7) is a beam scanning sequence circuit, and (8) is an antenna drive controller.

The conventional radar device a is configured as described above, and the transmitting/receiving antenna (1) emits microwave power into the gold space, receives the reflected wave from the target, passes through the transmitting/receiving switch (2), and receives the received signal. input into machine (4). The receiver (4) converts the received signal into a video signal and supplies it to the target detection circuit (5).

The target detection circuit (5) determines the presence or absence of a target from the supplied video signal, converts it into an all-digital signal containing information on target distance, azimuth, elevation, etc., and outputs it to the target tracking circuit (6). .

The target tracking circuit (6) classifies and stores the input target information, establishes the target's track and speed tL from the position information, and determines the target's position (!1 total) at the primary target tracking time. The prediction is calculated and the child pick-up first position and tracking request are supplied to the beam scanning sequence [path (7)].

In addition, the beam scanning sequence circuit (7) forms the entire search sequence for searching the search coverage area, and at the same time performs all interrupt processing in response to a tracking request from the target tracking circuit (6). Output to (8) and transmit at the same time t#@(pulse width, )) It 1'
, number of hits, etc.) is output to send@t3+. An antenna drive controller (8) drives the antenna in the instructed beam pointing direction. The transmitter (3) generates all the microwave power necessary for searching and tracking the target, and transmits and receives the transmitter (3).
Supply 2) with vinegar to the transmitter/receiver 4 antenna fi+.

In addition, the search frame time (time period required to search the entire predetermined spatial coverage area) TF of such a radar device is the sum of the time Ts required for search and the time Pt required for target tracking, as shown in the following equation. Tr = 'I's + Tt
-----・---(11Tt is also 9
It is determined by the number of pulse hits nl required for tracking, the number of targets to be tracked, and the pulse repetition period (hereinafter referred to as P Tt) required for target tracking as follows.

T+ =N, nt-P R'l' 1 ・”-
(21TS is also determined by the product of the number of beam spots n3 in the search coverage area and the pulse repetition period (hereinafter referred to as PRTs) required for the search, as shown in the first order.

T3 = NB −nB −P RT s −・−
” f31 Here, NB is determined by the search coverage area Ω and the search beam -○B in a first-order manner.

to B−η Ω/θB2 ・・・・・・・・・
(4) However, η is an arrangement coefficient determined by the beam arrangement.

[Problem to be solved by the invention]

In the radar device described above, the search frame time ′l
Since l is constant, if the number of pulse hits ni is increased to improve the tracking accuracy (the tracking accuracy is inversely proportional to 0%), or if it increases to the number of tracking targets, the tracking time T will change. By increasing f! The J-line time T8 is limited and the search coverage area is missed. Or T
If N is constant at +', the number nl of tracking pulse hits decreases due to an increase in N, which leads to a deterioration in tracking accuracy.

This invention has been made to solve this problem, and the array coefficient η is completely changed in response to the tracking time Tt which increases according to the number of tracking targets, and the number of search beam spots NB= By decreasing i, the purpose is to simultaneously secure q't, maintain the desired tracking accuracy, and prevent a decrease in the search coverage area.

[Means to solve the problem]

This invention VC and the related radar device have the number of beam spots k that can be searched from the search time that is reduced according to the number of targets to be tracked.
This is the addition of a ``beam spot number calculation circuit j'' that calculates gt and a ``search beam position calculation circuit'' that calculates all the spatial coordinates of the search beam so that the beam spots are arranged at a constant interval.

[For production]

Unlike conventional radar systems that search and track using a fixed beam spot array, this invention maintains the desired search coverage area and searches for targets using a search beam spot array that changes according to the number of targets being tracked. Therefore, it is possible not only to completely prevent the reduction in the search coverage area due to tracking, but also to make it possible to change the tracking accuracy to 1 [Embodiment] The 1st IA shows one embodiment of this invention. 1
) to (8) are exactly the same as the above conventional device, and (
9) is a beam spot number calculation circuit and a σtN4 search beam coordinate calculation circuit.

The beam spot number calculation circuit (9) calculates the number of beam spots to be searched in the allotted search time and inputs it to the search beam coordinate calculation circuit α. Search beam turret meter circuit QIVi From the number of search beam spots for the search coverage area, the total array interval is 1, and the 70th snow coordinate is calculated and output to the beam scanning sequence circuit (7).

In the radar device configured as described above, the target newly detected by the target detection circuit (5) and the target tracking circuit (
From the target that has already been buried in step 6), in the beam spot number calculation circuit (9), the time required for searching is calculated from equations (1) and (2) as shown in the following equation.

Ts-'■1F-Tt-TF-n1 ・PRTt ・
(5) Also, from equations (3) and (5), calculate the total number of projection beam spots as shown in the following equation.

NB n3 PRTI =: '+', -N-n
t, PItT.

However, in equation (6), TF, nl, PR'1
4, ns, PRT, is determined by the radar R[in, and once N is determined, NB is determined.

By searching for B in equation (6) and inputting it into the beam coordinate calculation circuit (, 11), it is possible to form a search beam array on the bow according to the number of targets to be tracked. Naru 1
, At this time, the following equation is obtained from the array coefficient ηC(4) and (6).

Therefore, compared to the conventional method in which the search frame time is constant and the entire beam is irradiated, the time required for target tracking Tt
The ijJ function provides a significant improvement over problems such as a decrease in the search coverage area or a deterioration in the receding accuracy due to an increase in the search area.

An example of the case where the beam is scanned over all the hemispheres 9 is shown in FIG.

Figure 2 (4) is a search coverage map when the number of tracking targets is 1.
Figure (B) shows the search area diagram of the present invention when the tracking (-1 Keyaki increases to 4), and the search area diagram of the conventional method when the tracking (-1 keyaki) increases to 4. Also, in the figure (a) beam spot for searching r, (b11 beam bore k for tracking
(C) is a missing part of the search coverage area due to tracking using the conventional method.

Furthermore, FIG. 2 also explains how to suppress an increase in search frame time due to an increase in the number of targets to be tracked in the conventional method.

〔Effect of the invention〕

As explained above, the present invention includes a mechanism for calculating the number of searchable beam spots corresponding to the number of tracking targets generated, and a mechanism for recalculating the coordinates of the beam spots. By adding this, it is possible to not only suppress the decrease in the search coverage area for target tracking, but also maintain the required tracking accuracy.

[Brief explanation of the drawing]

FIG. 1 is a system block diagram showing an embodiment of the present invention, FIGS. In the figure, +11 is a transmission/reception borrowed antenna;
(2) is a transmitter/receiver switch. (3) is a transmitter, (4) is a receiver, and (5) is a target detection circuit. (6) is a target tracking circuit, (7) is a beam scanning sequence circuit, (8) is an antenna drive controller, (9) is a beam spot number calculation circuit, an urn search beam coordinate calculation circuit,
(a) is the search beam spot; (b) is the tracking beam spot; (C) is the missing part of the search beam spot due to tracking in the conventional method. Note that the same reference numerals in each figure are the same or compatible. The amount of money is also shown.

Claims (1)

[Claims] A transmitting/receiving antenna that emits and receives radio waves, a receiver that receives waves from the transmitting/receiving antenna, a target detection circuit that detects a target using the receiver, and a target detection circuit that detects a target by using the receiver. a target tracking circuit for managing target information obtained from the target tracking circuit; a means for calculating the allowable time for searching from the target information from the target tracking circuit; and a means for calculating the beam scanning interval from the allowable time, the search coverage area, and the transmission repetition period. A radar device comprising: means for calculating; and means for calculating beam scanning coordinates from the beam scanning interval to form a search pattern.