JPS61270679A - Radar searching equipment - Google Patents

Abstract

PURPOSE:To detect only a received video signal of small area such as an aircraft and to detect its position automatically by handling the received video signal as a two-dimensional image and giving an area number to a group of the same received video signals. CONSTITUTION:The received video signal is converted by a binarization circuit 23 into a binary video signal 24. Then, binary video signals 24 in a two-dimensional array are given an area number 26 by an ara number giving circuit 25. Further, an area measuring circuit 28 calculates the area of each area number of the circuit 25 and a gavity center detecting circuit 27 detects the center gravity of a video amplitude as the difference between received video signals having each area number of the circuit 25 and the threshold value of the circuit 23. Then, a target decision circuit 33 nullifies the center position of gravity of a target having large area on the basis of the measured area of the area number and signifies the center point of gravity of a target having small area to detect the center position of gravity of the signified target, detecting the point target such as an aircraft automatically.

Description

[Detailed description of the invention] [Industrial application field] 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.

[Conventional technology]

Conventional radar search equipment displays the received video signal of the search radar on a PPI display, and the operator uses a trackball etc.
A marker was placed on the target on the PI display and the position was sent out as a target position (R, θ) signal.

FIG. 6 is a diagram showing an example of the configuration of a conventional device of this kind, in which (1) is a search radar, (2) is a transmission pulse signal, (
3) is a received video signal, (4) is a bearing antenna angle signal, (5) is a PPI display, (6) is a trackball, (7N is a target position IR, θ) signal, and 17B1 is a maquisition signal.

In Fig. 6, the search radar (11) is constantly rotating in the direction of the bearing, and the rotation angle is sent out as a bearing antenna angle signal (4).
2. At the same time, a transmission pulse signal (21) is sent out.

The reflected electromagnetic waves from the target are sent out as a received video signal (3) from the search radar (1+) and displayed on the PPI display (5). , identify the target with the trackball (6), and set the output of the trunk ball to the target position fR, θ
) signal (7A) and a signal from a relay contact indicating that the target has been designated 17 are sent as an acquisition signal (7B) to other equipment such as a tracking radar.

Figure 7 shows the transmitted pulse signal (2) and the received video signal (3).
(8) is an example showing the relationship with target echo 1.
, +91 is the clutter echo l.

In Fig. 7, an electromagnetic wave is emitted from the search radar (11) at the timing of the transmission pulse signal (2).The electromagnetic wave reflected from a point target such as an aircraft is a target echo 1 (8 ).Also, electromagnetic waves reflected by mountains, large buildings, etc. can be obtained as clutter echo 1 (
9).

FIG. 8 is a diagram showing one display example of PPI display +5+1 of the conventional radar search device shown in FIG.
PI display example: (+1) is a target echo 2.03 is a clutter echo 2.13 is a target indicating marker.

In Figure 8, the point targets such as 6 aircraft are transmitted pulse signals (
The target echo 1 (1
J] and the target echo 20υ. In addition, clutter such as mountains is displayed as clutter echo 1 (91, clutter echo 2θ2) with a pulse width larger than the pulse width of the transmitted pulse signal (2).In addition, in general, the reflection area of 9 is larger than that of the point target. The operator operates the trackball (6) to place target echo 1 (target indication marker 0 above 81).
3 and sends out the output of the trackball (6) at that position as the target position fR, θ) signal (7A).

At the same time, an acquisition signal (7B) indicating that the target has been designated is sent out.

[Problems to be solved by the invention] As described above, in the conventional device, the operator can
Detection of point targets such as aircraft on the CRT screen of the I display 1-.
Sending the target position fR, θ) signal requires the operator's skill and complicated operations. I cut it. If the area around the search radar is complex, there will be a lot of clutter, making it difficult to detect the target.

This invention measures the area of the received video signal and removes the received video signal with a large area such as clutter.12. The purpose is to detect only the received video signals in a small area such as an aircraft, and to fully automatically detect the position.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention treats a received video signal as a two-dimensional image.

A means for assigning an area number to a block of the same received video signal, a means for measuring the area for each area number, a means for measuring the target position (angle and distance) for each area, and two small areas. This method uses means for detecting the target position of the region.

[Effect]

In the apparatus according to the present invention, a received video signal is binarized to generate a binary video signal 1 to 1, and an area number is assigned to the binary video signal in the two-dimensional array by 17. Area and 1 position (angle) for each area number.

distance). Disable the large target position (angle, distance) of 1 area according to the area of each measured area number.
A small target position with 0 area (1 angle, distance) is valid, and a valid target position (angle, distance) is valid.

By detecting distance), point targets such as aircraft are automatically detected.

〔Example〕

FIG. 2 is a diagram for explaining an example of a video arrangement when the display example shown in FIG. 8 is binarized, and a◆ is an example of a binary video arrangement, (1 pixel).

In FIG. 2, the horizontal size of one pixel θ corresponds to a lunge bin, and II corresponds to the radar transmission cycle. 8th
When the display example shown in the figure is binarized, it becomes a pixel arrangement as shown in FIG. 2.

FIG. 3(a) is a diagram for explaining the outline of the operation of the area number assigning circuit (c) shown in FIG. 1, and FIG. Figure (1)) is a diagram for explaining the area number storage register string, and 0
1 is an area detection window, and one side is a storage register array with areas.

In the area detection window H, Ad is located at the position of a pixel to which an area number is to be assigned, and B is located at the position of an adjacent pixel to which an area number has already been assigned.

There are C, D, and E. Also, if the pixel width in the distance direction is m pixels, the area number of the pixel that has already been assigned an area number is
The past m+1 pixels are stored in the area number storage register array 071. The values of the binary video at positions A, B, C, D, and E are respectively F (A) ,
F (B), F (C), F (D).

F (E), and the contents of the area storage register array aη indicating the area numbers of the pixels at positions B, (', I), and E are respectively 1u11. Let Rfm-tl, R@, Rfm+11.

Assuming that the area number fN of the pixel located at position A is the area number fN, the theory of area numbering is expressed by the following formula (9).

F (A) = 0 → N = 0 ・・・・・・
...filF(A)=1, F(B)=F
(C)=F(D)=F(E)=0-)N=k
(2) However, , is the smallest natural number among the area numbers not stored in the area number storage register column +171.

F(A)-F(B)=t, F(cl=F(n)
=F(g)=o→N=R(n ・
・・・・・・・・・・・・(31F(^)-F (E)-
1, F (c) = F (D) - o → N = l'j
l m+11 ・・・・・・
... f41F (A) = F (D) = 1
, F (C)= (1→NR)...(5)F(
A)-F(C)-1, F(B)-F(D)-F(E)20→N=Rfm-1)...
......(61F(A)=F'(C)-F'(o)
−1, −*N=R(m−1)・・・・・・・・・・・・−
...(71 F(A)===F(C)=F(Ei==t, F(
D)=o-*N=R(m-h l*R(m+1
) =Rfm-1) -(81F(A)-F(n)=
F'(c)=1, F(D)=F(E)=
o→N=R(m-1), R(ll=R(m-11-=(
9117 Therefore, scan l- with area detection window QI19
, is equivalent to scanning with 8 concatenations, and the same area number is assigned to the part where the binary video is concatenated]7.

Figure 4 is an example of the binary video array shown in Figure 2 Q4)? This is a diagram for explaining an outline of the output of the area number assigning circuit (c) shown in FIG. 1 when input, Qll is an example of assigning an area number, QI#'i area number 1. (To) is area number 2, Qυ is area number 3. (c) is area number 4.

The binary video signal e24 shown in FIG. 1 corresponds to the binary video array example (1411c) shown in FIG.
When 141' is manually input to the area number assigning circuit (c), (1
According to equations 1 to (9), target echo 1 (8) has area number 2 (Ll), and clutter echo 1 (9) has area number 1 (Ll
, target echo 2αυ is output as area number Ji34 (c), and clutter echo 2H is output as area number 3Qυ. In addition,
The clutter echoes 2fi3 at the upper and lower ends are caused by the endless rotation of the search radar (1) shown in FIG. 6 in the direction of the bearing. Since the signals are input as a combined video signal, the same area number 30It is assigned as shown in FIG.

FIG. 1 shows one embodiment of the present invention.
B is the binarization times %, +23A) is the threshold, 341 is the binary video signal, (c) is the area number assigning circuit, @ is the area number signal, @ is the center of gravity detection circuit, @ is the area measurement circuit, (2 )
is the delayed snoring circuit, (7) is the delay area number signal, 00 is the area area signal, and (to) is the area gravity center point IR.

θ) signal, (to) is a target determination circuit.

In FIG. 1, a search radar (11), a transmission pulse signal (
2), the received video signal (3), the bearing antenna angle signal (41), and the operations of the PPI indicator (5) are the same as those shown in FIG. 6, and their explanations will be omitted.

The binarization circuit (c) converts the received video signal (3) to a threshold value (23
A) Binary video signal C! which is "0" when the following is true and "1" otherwise. 41'. Area number assignment circuit (
In (e), as shown in FIG. 7, an area number is assigned to each pixel according to formula m-(9) during the valid period of the received video for each transmission pulse, and an area number signal (c) is generated. The area measuring circuit (2) increases the area of the corresponding area number by 1 to 1-1 and stores it for each pixel when the area number (1) is other than "0". Center of gravity detection circuit @ is area number signal (a)
When f-Oi is 1, the center of gravity position tR, θ) of the corresponding area number is determined using equation 01 and stored.

Center of gravity position (R, θ)2...01 Th: Threshold P(R, θ): Received video amplitude of pixel (R, θ) Binary video signal = When O, K=0 When binary video signal=1, K=1 The delay circuit delays the area number (A) by Td! ,.

A delay area number signal (7) is sent out. In addition, the delay time T
d needs to satisfy formula 011. however.

Td is an integral multiple of the transmission repetition time of the search radar (11).

Td〉θB10B ・・・・・・・・・
...(IllθB: Transmission beam width in the bearing direction of the search radar θB = rotational speed in the bearing direction of the search radar. Also, the area measuring circuit (to) described above uses the delay area number signal c
Using lf1 as an address, the area of the corresponding area number is sent as area area signal 00. Similarly, the 1 centroid detection circuit plane is set to 1 with the delay area number signal (7) as the address.
The center of gravity position f(R, θ) is sent as the region center of gravity tR, θ) signal 0.

The target determination circuit (to) receives the area area signal C11l and the area center point (R, θ) signal 03, and when the area area signal 6υ is larger than the reference value, it receives the area center point (R, θ) signal C(3). When the area area signal el11 is smaller than the reference value, the area center of gravity point (R, θ) signal 63 is made effective and sent as the target position tR, θ) signal (7A). At the same time, it also sends out an acquisition signal (7B) which means that the target has been detected. Figure 5 shows the target position (7B) in Figure 1.
R, θ) signal f7Al (ff is a diagram for explaining, 641 is the target 1 position (R, θ) signal, and (to) is the target 2 position (R2O) signal. Binary video of FIG. If the signal Q4 is an output not shown in FIG. 2, a region number as shown in FIG. 4 is assigned, and the region number IQ with a large area is
value and 1 area number 3011 are suppressed.

Target 1 position iR, θ) signal (b) and target 2 position tR
, θ) signal (to) is detected as the target position (R, θ) signal (7Al) and is sent to the PPI display (5) and other equipment such as a tracking radar.The PPI display (5) indicates the target position Upon receiving the (R, θ) signal (7A), a target indication mark αI is displayed at the corresponding position on the CRT surface 1-.

〔Effect of the invention〕

As described above, according to the present invention, clutter such as mountains and buildings can be suppressed and point targets such as aircraft can be automatically detected.
This can greatly contribute to shortening target detection time and reducing the burden on the operator.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of an embodiment according to the present invention, and FIG. 2 is a diagram showing an example of a video arrangement. Fig. 3 is a diagram for explaining the overall operation of the area numbering circuit, Fig. 4 is a diagram for explaining the outline of the output of the area numbering circuit, and Fig. 5 is a diagram for explaining the outline of the output of the area numbering circuit. Figure 6 is a schematic diagram. FIG. 7 is a diagram showing the configuration of a conventional device, and is a diagram showing the relationship between a transmitted pulse signal and a received video signal, in which (l: search radar, t7A) ti target position (R. θ) signal, @ is the binarization circuit, +23Al is the threshold value, (
C) is an area number assigning circuit, @ is a center of gravity detection circuit, @ is an area measuring circuit, rA is a delay circuit, and (C) is a target determination circuit. In Figure 9, the same or corresponding parts are shown. The same reference numeral is indicated by a j-.

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;
For each area number of this area numbering circuit, the area (number of pixels)
an area measuring circuit for measuring the area, a center of gravity detection circuit for detecting the position of the center of gravity of the video amplitude of the difference between the received video signal for each area number of the area number assigning circuit and the threshold of the binarization circuit; a delay circuit that delays the area number signal of the numbering circuit; and a target determination circuit that determines the center of gravity position of the center of gravity detection circuit as valid or invalid according to the area of each delay area number signal output from the delay circuit. , and means for transmitting the effective center of gravity position of the target determination circuit as a target position signal.