JP2591226B2 - Radar signal transmission system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a radar signal transmission system, and more particularly to a radar signal transmission system for digitally transmitting a radar video signal excluding a target signal from a target at a low speed.

[Conventional technology]

In a general radar device, a signal obtained by directly converting a reflected signal into a video signal is referred to as normal video. This normal video shows the radar receiver noise,
Fixed clutter, which is a reflection signal from mountains and buildings, and weather crack, which is a reflection signal from rain clouds, occupy most of the
There are few target signals which are reflection signals from a target such as an aircraft.

The conventional radar video low-speed transmission method is a transmission method in the case where the above-mentioned fixed clutter and weather clutter described above are mainly intended to be displayed on a screen as a background of a screen in which only a target is extracted.
The radar video display screen by one scan of the radar is divided into sections covering a certain angle range, and a video on a scanning line (hereinafter referred to as a sweep) in the section is directly subjected to AD.
This is a method of converting and outputting. As shown in FIG. 3 (a), the sections to be transmitted within the time of one scan are sections # 1-1 to # 1-m at intervals of n sections, in this case, intervals of 5 sections. First, only the normal video in the m section is transmitted. In the next scan, as shown in FIG. 3B, the next # 2-1 section, ##
In the next scan, the normal video of the # 2-2 and # 3-2 sections is transmitted as shown in FIG. As shown in FIG. 4, the screen of one scan reproduced on the receiving side is a method of transmitting radar video for one scan by multiplying by # 1 and # 2 of different scanning sections transmitted on the transmitting side. , # 3, etc., and a background normal video signal can be transmitted with a small line capacity.

[Problems to be solved by the invention]

In the conventional low-speed transmission method described above, a target signal related to a moving target in normal video is also A / A.
When the target signal is present in the transmission section for D-conversion and transmission, the bright spot of the target signal is used and displayed on the reproduction screen of the receiving side a plurality of times until the next video update.

FIGS. 5 (a) to 5 (d) show transmission side # 1 to # 4, respectively.
A moving target 10 such as an aircraft is shown by displaying successive display images of scanning.
When 1 moves in the azimuth direction as shown by the arrow,
FIG. 5 (a) shows a state in which the target signal 102 is displayed in the # 1 scan and the # 3 scan in FIG. 5 (c). As shown in FIG. And # 3-
Bright spots of the same target are displayed in two sections as afterimages 106 until the next video update. In this case, the actual target should exist at the position indicated by the dotted line as the target 104. In addition, 105 is a synthetic fixed clutter.

Normally, normal video is displayed as a background of a screen on which only the target is extracted. Therefore, there is a disadvantage that these target luminescent spots existing as the afterimage 106 are mistaken for the original target signal.

An object of the present invention is to provide a radar signal transmission system in which the above-mentioned disadvantages are eliminated and a target luminescent spot existing as an afterimage is largely suppressed.

[Means for solving the problem]

In the system of the present invention, the radar is one in 360 degrees in all directions.
A radar signal that transmits radar video for one scan in several scan times by dividing radar video obtained by scanning into sections of a predetermined angle unit and outputting several of these sections in one scan time In the transmission method, radar video is stored on the transmitting side,
Scan integration means for integrating the radar video in the same section as the stored radar video over a predetermined number of scans and outputting the integrated video, and integrating the integration video obtained by the scan integration means by dividing by the number of integration scans and averaging them Integrated video averaging means for outputting an averaged video, the receiving side storing the averaged video transmitted from the transmitting side, and outputting the averaged video to the radar video display screen updating path in the same section. And a scan reproduction unit for suppressing the afterimage of the target signal appearing on the radar video display screen.

〔Example〕

 Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. On the transmission side, the normal video is converted into a digital signal by the A / D conversion circuit 1 and transmitted to the scan integrator 4. The scan integration unit 4 includes the memory 2 and the scan integration control circuit 3. The memory 2 has a memory capacity corresponding to the number of sections obtained by dividing one scan, and the radar video is sequentially written into each section by a write signal of the scan integration control circuit 3. When there is an addition signal from the scan integration control circuit 3, the memory 2 adds the radar video to the information written in the memory 2. The scan integration control circuit 3 generates an ACP (Azimuth Change Pulse) and an ARP (Azimuth
Using a reference pulse, a write / read signal and an addition signal are sent to the memory 2. The write signal is written to the section of the memory 2 determined by ACP and ARP for each trigger. The addition signal is output to the memory 2 together with the write signal for the integral number required for each section of the memory 2. In addition, the addition signal is controlled so that the sections equally divided by the number of sections transmitted in one scan terminate the respective integral numbers for each scan, and further, the integral number of the next section terminates in the next scan. To control the memory 2. A readout signal is output to the section where integration has been completed, and is output to the divider 5 of the integral video averaging section 6 as integrated radar video together with information on the section.

The integral video averaging unit 6 divides the integral video output from the memory 2 by the divider 5 by the number of scan integrals, and outputs an averaged radar video. The integration and averaging of this radar video is shown in FIG. FIG. 2 shows an example in which signals of 20 scans are integrated and averaged, and shows a case where aircraft information exists for only one scan of n-19 scans, and aircraft information is noise of other scans. And averaged over 20 scans. As a result, information on the aircraft is output as an averaged radar video substantially equivalent to noise.

The modem interface 7 is a circuit for interfacing the divider 5 and the modem 8, and the modem 8 outputs the averaged radar video to the receiving side via the transmission line 9.

On the receiving side, the averaged video transmitted via the transmission line 9 is received by the modem 10 and converted by the modem interface 11 into a signal to be used in the scan reproduction 14. The scan reproduction unit 14 includes the memory 12 and the scan reproduction control circuit 13. The memory 12 is a memory for storing an averaged radar video for a scan, and a scan reproduction control circuit.
Controlled by 13. The averaged radar video transmitted via the modem interface 11 is stored in the memory 12 by the scan reproduction control circuit 13 in accordance with the section information included in the averaged radar video signal.

The scan reproduction control circuit 13 internally generates a trigger, an ACP and an ARP, and outputs them to the outside, and at the same time, sends a read signal of a section corresponding to the ACP and the ARP to the memory 12.

With this read signal, the averaged radar video output from the memory 12 is converted into an analog radar video by the D / A conversion circuit 15 and output to the outside as an averaged radar video.

〔The invention's effect〕

As described above, the present invention can reduce the ratio of signal components left by a target signal moving at a high speed such as an aircraft by integrating the radar video for a predetermined plurality of scans and then averaging the integrated signals. Even when displayed, there is an effect that there is no danger of being mistaken for target information.

[Brief description of the drawings]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG.
3 (a) to 3 (c) are explanatory diagrams of the transmission operation of the conventional radar signal transmission system, and FIG. 4 is a diagram illustrating the transmission operation of the conventional radar signal transmission system in the embodiment of the figure. Explanatory drawing of receiving operation, FIGS. 5 (a) to 5 (e)
FIG. 3 is an explanatory diagram of the influence of a residual image due to a target signal in a conventional radar signal transmission system. 1 A / D conversion circuit, 2 memory, 3 scan integration control circuit, 4 scan integration unit, 5 divider, 6
...... Integrated video averaging unit, 7 ... Modem interface, 8 ... Modem, 9 ... Transmission line, 10 ... Modem, 11
… Modem interface, 12… Memory, 13… Scan reproduction control circuit, 14… Scan reproduction unit, 15… D /
A conversion circuit.

Claims (1)

(57) [Claims] 1. A radar video acquired by a radar in one scan over 360 degrees in all directions is divided into sections of a predetermined angle unit, and several of these sections are output in a time of one scan, thereby obtaining several scans. In a radar signal transmission system that transmits radar video for one scan in time, the radar video is stored on the transmission side, and the radar video in the same section as the stored radar video is integrated over a predetermined number of scans and output as an integrated video Scan integrating means, and integrated video averaging means for outputting an averaged video obtained by dividing the integrated video obtained by the scan integrating means by the number of integration scans and outputting an averaged video. And stores the averaged video in the same section until the radar video display screen is updated. A radar signal transmission system comprising: a scan reproduction unit that suppresses an afterimage of a target signal that is output in an image and appears on a radar video display screen.