JPH0381115B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radar image display device, and more particularly to a radar image display device that facilitates recognition of weak aircraft echo signals with a low blip scan ratio.

Conventionally, very weak aircraft echoes (video) are affected by radio wave propagation conditions and weather conditions, so BSR
(BLIP SCAN RATIO) was low, making it difficult to detect visually on a radar image display device.
In addition, weak video signals have a short storage time and disappear quickly due to lack of stored energy. Therefore, it cannot be recognized as a continuous aircraft echo and cannot be detected.

The present invention provides a radar image display device that solves the above-mentioned drawbacks and makes it possible to easily recognize even weak aircraft echoes.

In order to achieve the above object, the present invention provides a method for storing images.
IC memory, data writing to memory, erasing,
It is equipped with a control circuit for readout, etc., and applies a predetermined attenuation characteristic to the data obtained for each scan and the data at the corresponding address stored in the memory for areas designated in advance for video processing when storing images. The configuration is such that the data obtained by performing processing that takes into account the data is compared, and the data with the higher level is written into the memory as new data.

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

The embodiment of the present invention is for converting a PPI display into a TV display, and as shown in FIG. an A/D converter 2 that receives a video signal and converts it to digital; and an address conversion circuit 1.
an image storage memory 3 designated by
A trail control circuit 4 displays a trail by reducing the brightness of the video stored in the radar during the next radar scan, and controls the operating state of the trail control of the trail control circuit 4 for a predetermined specified area. an area setting circuit 5 for changing the trail display state, and the image memory.
For reading out in synchronization with the synchronization signal for TV display,
It includes a read address circuit 6 and a D/A converter 7 which converts the read digital video signal into a TV video signal.

Address conversion circuit 1 receives the direction signal from the radar.
ACP (Azimuth change Pulse) and ARP
(Azimuth Reference Pulse) to obtain the direction of the antenna (azimuth O), and perform XY conversion from RO to obtain the X-Y coordinates (address) of the memory corresponding to each range (distance R) of the radar video. It is. The A/D converter 2 converts analog video signals in real time and stores them in the image storage memory 3 in order of distance. The image storage memory 3 is used to write data into the storage memory 3 based on information from the address conversion circuit 1 and the A/D converter 2 between TV video reading operations in which the read address circuit 6 exclusively uses the image storage memory 3. However, when writing to the memory 3, it is related to the trail control circuit 4, and if a trail display function is added to the video display, the same address position is written before writing to the memory 3. After data is read and its value is attenuated according to a certain law, trail control is performed in which it is compared with new data and the larger one is set as the rewritten data. The area setting circuit 5 uses the upper few bits of the output of the address conversion circuit converted into the orthogonal coordinate system to read out the situation stored in a predetermined area setting map as shown by the shaded area in FIG. , determines whether the data is within the set area, and if it is within this area, executes processing different from trail processing control for other areas. An example of this is changing the attenuation constant related to the trail processing, and it is also possible to store the trail for a long time. In particular, if the attenuation is zero, it is even possible to preserve the wake forever.

Normally, the position of an aircraft's echo changes every time the radar antenna scans, so by setting the attenuation to zero, the video signals that have already been written will not disappear, and new video signals will be added one after another. A wake as shown in the figure is stored in an image memory, and by reading it in TV synchronization, a TV image is obtained and the display shown in FIG. 3 is performed.

That is, if the area is set in the area setting circuit 5 using the upper bits of the address signal from the address conversion circuit 1, a signal is sent to the attenuation curve setting circuit 8 to inform the attenuation curve setting circuit 8 of the situation. The attenuation curve setting circuit 8 has a plurality of video amplitude versus radar scan attenuation characteristics, as shown in the example of the attenuation curve shown in FIG. Therefore, it can be used for normal attenuation curves and for cases with area settings. This information is sent to the trail control circuit 4, which attenuates the currently read data from the image storage memory according to the characteristics of the selected attenuation curve. If F is used here, as in the example shown in FIG. 4, there will be no attenuation, and if A is used, attenuation will occur rapidly. The output of the trail control circuit 4 is sent to a comparator 9, where it is compared with the video data after A/D conversion, and the larger one is re-stored in the image storage memory 3 as re-write data. If F of the attenuation curve in FIG. 4 is used, the image must be erased from time to time. This can be done automatically at certain time intervals or manually. When using F, if you leave it for too long and do not erase it, noise etc. will accumulate throughout the image memory.
This is because it will interfere with the detection of the wake.

This example shows an example and does not specify the present invention.In other words, as for the region setting method, it is also possible to use the polar coordinate method, and it is possible to use a polar coordinate method without using the region setting memory and to set the area at a constant distance from the center of the radar. It is also possible to make a determination based on the distance of , or to set it on the control panel of the scan conversion device. Nor is it based on scan conversion.

By adopting such a configuration in the present invention, even distant and faint aircraft that could not be detected using PPI images that were conventionally viewed only by real-time video can be detected without the need for complex and enormous video processing. Since the time-series correlation of videos can be visually monitored at all times, it is highly effective in early detection of aircraft intruding into airspace.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention;
FIG. 2 is a diagram showing an example of memory area setting, FIG. 3 is a diagram showing an example of track display according to the present invention, and FIG. 4 is a diagram showing an example of attenuation curve setting. In the figure, 1...address conversion circuit, 2...
A/D converter, 3... Image storage memory, 4... Trail control circuit, 5... Area setting circuit, 6... Read address circuit, 7... D/A converter, 8...
Attenuation curve setting circuit, 9...comparison circuit.

Claims (1)

[Claims] 1 A memory for storing radar video in correspondence with position coordinates, an area setting circuit for setting a predetermined area of the display area, and a area setting circuit for setting a predetermined area in the display area, and a memory for storing radar video in correspondence with the area setting circuit, and a area setting circuit for setting a predetermined area in the display area, and a a processing circuit that performs processing that takes into account a predetermined attenuation characteristic determined by the above processing and outputs the processed data; and a comparison circuit that outputs a signal of a large level, the output of the comparison circuit is replaced with data at the corresponding position coordinates of the memory and written, and the signal read from the memory is displayed as a video. radar image display device.