JPS6166173A - Search radar - Google Patents

Abstract

PURPOSE:To control clutter and display only a point target of an aircraft, etc., by handling a received video signal as a 2-dimensional image and displaying a video signal of the area number of small area on a PPI display apparatus. CONSTITUTION:A received video signal 3 from a radar 1 is applied to a circuit 22 through a binarized circuit 20 as an input and allocated with the area number per each image element. A measuring circuit 24 increases by one of the area number corresponding to the case where the area number signal is other than zero and stores it. A delay circuit 28 delays signal 23, signal issuing pulse signal 2, signal 3, bearing antenna angle signal 4 respectively and sends out correspond ing signals 26, 29, 30, 32. The circuit 24, using the signal 26 as the address, sends out the area of the corresponding area number as a signal 25 and the signal 25 is compared with the reference area in a judging circuit 27, judged for its validity and non-validity and if the judgement is in the affirmative, a displaying video signal 31 is transmitted to the PPI display apparatus 5.

Description

[Detailed description of the invention] [Technical field of invention] This invention eliminates clutter such as mountains and buildings.

This invention relates to the improvement of radar search equipment for detecting point targets such as aircraft.

[Prior art]

Conventional radar search equipment uses the search radar's received video signal'
It was displayed on the 1iPPI display.

FIG. 1 is a diagram showing an example of the configuration of a conventional device.
1) is a search radar, (2) is a transmitted pulse signal, (3) is a received video signal, (4) is a bearing antenna angle signal, and (51FiPPI indicator).

In Fig. 1, the search radar (1) is rotating at a constant rate in the bearing direction, and while transmitting the rotation angle as a bare link antenna angle signal (4), it periodically radiates magnetic waves (1), and at the same time transmits pulse signals ( 2) is sent. The reflection box magnetic waves from the target are sent out as a received video signal (3) from the search radar (11) and displayed on the PP optical display 5.

Figure 2 shows the transmitted pulse signal (2) and received video signal (3)
In this example, (6) is the target echo 1° and (7) is the clutter echo 1.

In Fig. 2, an electromagnetic wave is emitted from the search radar (11 power) at the timing of the transmission pulse signal (2), and the electromagnetic wave reflected by a point target such as an aircraft is a target echo with approximately the same pulse width as the transmission pulse signal (21). 1 (6). Also, electromagnetic waves reflected from mountains, large buildings, etc., produce a clutter echo 1 (
7).

PPI of the conventional radar search device shown in Figure 1
It is a diagram showing an example of one display on the CRT screen of the P indicator (51), (8) is an example of the PP display, (9) is the target echo 2, (
1 (6 with IH clutter echo 2.

In Figure 3, a point target such as an aircraft is a transmitted pulse signal (
2) Target echo 1 (
61, displayed as target echo 2 (9). In addition, clutter such as mountains is larger than the pulse width of the transmission pulse signal (2), and the clutter echo 1 +71. Taratsuta Echo 20
It is displayed as 1. The clutter reflection is large in terms of intensity (amplitude) as well.

Therefore, in the conventional radar search device as shown in Fig. 1, P
Detecting targets such as aircraft on the CRT screen of the PIP indicator (5) requires skill and is also difficult.

[Summary of the invention]

This invention treats the received video signal as a two-dimensional image, assigns an area number (label) to the same block, and erases the video signal with the area number having a large area by giving a total area of 11111 L for each area number. By displaying a video signal of a small area number of one area on a PP optical display, a means for eliminating the drawbacks of the conventional method is provided.

[Embodiments of the invention]

FIG. 4 is a diagram for explaining an example of a video arrangement when the display example shown in FIG. 3 is binarized, and the following is an example of a binary video arrangement (13H pixels).

In FIG. 4, the thick awn in the horizontal direction of one pixel az corresponds to a lungi bin, and the vertical line is the transmission period of the radar.

When the display example shown in FIG. 3 is binarized, it becomes the pixel arrangement example shown in FIG. 4.

FIG. 5 is a diagram for explaining the outline of the operation of the area number assigning circuit Q3 shown in FIG. (b) A diagram for explaining the tri area number storage register array.

03 is an area detection window, and 041 is an area number storage register string.

In the area detection window 031, A is at the position of a pixel to which an area number will be assigned from now on, and adjacent to this is the position of a pixel to which an area number has already been assigned, VCB, JD.

E is 5. That's too much. If the pixel width in the distance direction is m pixels, the area numbers of pixels to which area numbers have already been assigned are stored over the past m+1 pixels by the area number H1 storage register column 041. ing. A, B.

(The head of the binary video at positions 3, D, and E, respectively.

'(Al・F(Bl・”(C!l・
F (DI・”(El Toshi・B・C
The contents of area memory 1/register column 04) indicating the area numbers of pixels at positions D and E are respectively converted to R(1 and R(m-1).
- Let R9t be R(m+1), and let N be the area number of the pixel located at position A in 8th and 8th, then the theory of area numbering can be expressed by the following formulas i11 to (9i).

F(Al=0→N=0 ・
・・・(11FfAl"-'1.h'fchome31
=)”(cl= F(])l= F(El=o →N
= k, 121, where k area number storage register string α
4) The smallest natural number among the area numbers not stored in 4).

F(Al-F(B)-1, F(cl=F(D)"1(p
)-0 groanN = R(1)...(3) '(At-F(ml-1,F(cl=F(DJ=0
=+N=R(m+1)...-(4) 'F(A)''FfDl=1. F(cl””O→N
-R(m)...(5)'(A,)='(cP'・F(
Bl=F(DJ-F(gl=o→N=R(m 1)...
・(6) F(A)-F(Ol-F(DJ-1, -JJ=R(m-
1) −(7)F(A)=Ffc)−F(Bl=
1. F(D)-0→N=R(m 1).

R(m+1)-R(m-1)-
-181F(A)=F(B)=F(0)=1. F
fD)−F(E)=0→N=R(m 1).

R(11””R(m-1) ・
(91) Therefore, scanning with the area detection window 03 is equivalent to scanning with 8 concatenations, and the same area number is assigned to the portions where the binary video signals are concatenated.

FIG. 6 is a diagram for explaining the outline of the output of the area number assigning circuit shown in FIG. 7 when the binary video array example QL of [4] is input; 16
+ is area number 1. Q? l is area number 2. Mackerel is area number 3
, 01 is area number 4.

Binary video signal c! shown in FIG. B is 2 shown in Figure 4 1.
Corresponds to the value video array example Ql, and 2-run video array example αb
When inputting into the area number assigning circuit, (formula 11 ~ (9)
According to the formula, flllllll-1(6) is the area number 2(1
71, clutter echo 1 (7) is area number 10G, target echo 2 (91 is area number 4a9. clutter echo 2 (
IItJ, area number 3 (can be output as III.
The clutter echoes 201il''i' at the upper and lower ends of the search radar (1: shown in Figure 1) rotate endlessly in the bearing direction, so they are input as a combined video signal, so they are the same as shown in Figure 6. Area number 3G+8 is assigned.

FIG. 7 shows one embodiment of the present invention, in which 0
0 is a binarization circuit, 0111 is a binary video signal, 02
is an area number assigning circuit, CI3 is an area number signal, 041
is the area measurement circuit, (to) is the area area signal, ■ is the delayed area number signal, @ is the display judgment circuit, @ is the delay circuit, (c) is the delayed transmission pulse signal, (to) is the delayed bearing anti-ten angle signal , C31+H display video signal, and 03 is a delayed received video signal.

In FIG. 7I, the received video signal (3) is binarized by a binarization circuit to generate a binary video signal c2υ.

The area number assigning circuit starts from "0" to "rOJ" when the transmit pulse signal tel changes from "1" to rOJ for each transmit pulse.
1", during the period of 1, a region number is assigned to each pixel according to formulas 11 to (9), and a region number signal (c) is generated. iTn product measuring circuit c!4) Each time the area number signal (C) is other than 0, the area of the corresponding area number is incremented by 1 and stored. The delay circuit (2) receives the area number signal (
C), transmission pulse signal (21), reception video signal (3).

Each signal of the bearing antenna angle signal (4) is II
I.

delay, delay area number signal 弼, delay transmission pulse signal 翰, delay bearing antenna angle signal (7).

Send out delayed received video signal ■. Note that Td can be expressed using a button expression. However, Td is an integer of the transmission repetition time of the search radar.

T(i > θB/θB θB = Transmission beam width in the bearing direction of the search radar δB = Rotational speed in the bearing direction of the search radar Area measurement circuit. 0 is the area of the corresponding area number using the delay area number signal ■ as an address. It is sent as an area signal (c).The display judgment circuit □□□ compares the area number signal and the reference area, and is invalid when the area is greater than the reference area, and F when it is less than the reference area.
It is determined that it is effective, and when it is invalid or the delay area number signal is "0"
When the noise level received by search radar (1) is equivalent to white noise.

Displays delayed received video signal 03 when enabled Video signal c
111. The PPI display device (5) is a delayed transmission pulse signal line and a delayed verification ring antenna angle signal (to).
1 display video signal 60 is displayed.

FIG. 8 is a diagram showing an example of the display on the CRT tube surface of the PPI display (5) shown in FIG.

In FIG. 8, the clutter echo [71,
The 2 clutter echoes are erased, and the target echo 1 (61
, 1 Kusunoki Echo 2 (9) only is displayed.

〔Effect of the invention〕

In this way, the present invention allows relatively simple signals (91,
.

Through processing, clutter such as mountains and buildings can be suppressed and only point targets such as aircraft can be displayed, making it possible to easily detect aircraft, etc., which can greatly contribute to reducing the burden on the operator.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of the configuration of a conventional device, FIG. 2 is a diagram showing an example of the relationship between a transmitted pulse signal and a received video signal,
FIG. 3 is a diagram showing one display example of a conventional device, FIG. 4 is a diagram showing an example of a video arrangement, FIG. 5 is a diagram for explaining the outline of the operation of the area number assigning circuit, and FIG. FIG. 7 is a diagram for explaining the outline of the output of the area number assigning circuit.
FIG. 8 is a diagram showing the configuration of an embodiment, and FIG. 8 is a diagram showing one display example of the device of the present invention.
PI display, circle is binarization circuit, circle is area numbering circuit,
CI4 is an area measuring circuit, @ is a display determination circuit, and @ is a delay circuit. In FIG. 1, the same or corresponding parts are designated by the same reference numerals.

Claims (1)

[Claims] A search radar for obtaining a received video signal reflected from a target object such as an aircraft; a binarization circuit for binarizing the received video signal of the search radar; an area numbering circuit that assigns a number;
An area measuring circuit that measures the area (number of pixels) for each area number of this area numbering circuit, a delay circuit that delays the area number signal of this area numbering circuit and the received video signal from this search radar, and this delay A display judgment circuit that judges the delayed received video signal of this delay circuit as valid or invalid according to the area of each delay area number signal of the circuit, and a display judgment circuit that displays the display video of this display judgment circuit on the screen of a CRT. PPI
A radar search device comprising a display device.