JPH03264879A - Radar video compression system - Google Patents

Abstract

PURPOSE:To make the capacity of a circuit low and thereby to reduce the cost of maintenance such as the rental fee of the circuit, by providing a digitizing means, a block dividing means, a data storing means, a clutter detecting means, a data averaging means, a data editing means, and a timing control means. CONSTITUTION:A digitizing means 1 digitizes a radar row video for each sweep video and a block dividing means 2 divides a digital signal by a distance into data blocks, while a data storing means 3 stores data of each block. A clutter detecting means 5 makes discrimination as to whether or not a clutter signal exists in each block, and outputs only the data of the block containing a clutter, while a data averaging means 4 receives the data of the block wherein the clutter exists, and takes the average value of the data in the block. A data editing means 6 edits the blocks in the same azimuth on the basis of the data of each block, the average value outputted by the means 4 and the result of detection of the means 5. A timing control means7 controls an operation timing of each means.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a radar video compression system, and more particularly, to a radar video compression system for compressing clutter-suppressed raw radar video output from a receiver of a radar device to a display device. This invention relates to a radar video compression system for digital transmission.

[Conventional technology]

Conventionally, when radar video output from a receiver of a radar device is digitally transmitted to a display device at a remote location, the radar video is simply AD converted and transmitted.

As shown in Figure 3(a), the radar video output from the receiver of the radar device contains reflected signals (hereinafter referred to as target signals) from objects moving at high speed such as aircraft.
Figure 3 (b) shows a radar low video that includes reflected signals from fixed objects such as buildings and mountains, and meteorological phenomena such as falling snow (hereinafter referred to as clutter signals), and receiver noise signals. As shown, there is a processed video that suppresses the clutter signal and consists of only the target signal and receiver noise signal.

The present invention relates to the case of digitally transmitting the radar low video of both videos.

[Problem to be solved by the invention]

Sampling when digitizing the radar row video described above uses fine time quantization units in order not to reduce the range resolution of the target. For this reason, high-capacity digital lines are used for transmission, but
Another drawback is that it is necessary to bundle a large number of small-capacity digital lines for time-division transmission, resulting in high maintenance costs such as usage fees for the digital lines.

Furthermore, as shown in FIG. 4, sampling of the radar low video is uniformly performed over the entire distance range of a so-called sweep video in the same direction, and the target signal and clutter signal contained in the radar low video are transmitted. This clutter signal is distributed over a wide range in the distance direction of the sweep video, and is, so to speak, one solid signal. This clutter signal can be used to determine whether the radar device is operating normally or not by using the display position of the signal, to confirm the relative position of the target signal, and to understand the weather conditions around the target signal. Since the target signal is used as a target signal, precise range resolution is not required. Therefore, fine amplitude changes in the clutter distance direction are not necessary for display purposes, but in the conventional method, this clutter signal is also finely sampled as shown in Figure 4, so the above-mentioned clutter signal Due to its nature, there is a lot of redundant data, which has the disadvantage of being inefficient in terms of transmission.

[Means to solve the problem]

The radar video compression system of the present invention is a radar video compression system for digitally transmitting a radar video signal to a display device, and converts analog radar video into a digital signal for each sweep video as video in the same direction. digitizing means; block dividing means for dividing the digital signal into data blocks by dividing the digital signal into data blocks; the block dividing means; data storage means for storing data for each block; and each block in the data for each block. a clutter detection means for determining whether or not a clutter signal exists in the block by looking at a predetermined direction and outputting only the data of the block where the clutter signal exists; data averaging means that takes an average value and replaces each data with one average value, data in blocks output from the data storage means, data regarding the average value output from the data averaging means, and the clutter. a data editing means that collects, edits and outputs blocks for each same direction based on the detection results of the detection means; and a data editing means that generates a clock signal necessary within the system and uses a radar trigger signal input from an external input and the clock signal to and timing control means for controlling input/output timing.

Further, in the radar video compression system of the present invention, the clutter detection means detects clutter when the signal exceeds a predetermined threshold level, and the continuity thereof is greater than the width of the target signal in the distance direction. It has a configuration in which the determination is made using the detection criteria.

〔Example〕

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

FIG. 1 is a block diagram of an embodiment of the present invention, which includes a digitizing means 1 that digitizes an analog radar low video for each sweep video, and a digital signal that is divided into data blocks by the digitizing means 1 in units of distance. a block dividing means for storing data for each block, a data storage means 3 for storing data for each block, and determining whether or not a clutter signal exists in each block in the data for each block, and outputting only data for blocks containing clutter. a clutter output means 5 which receives the data of the block in which clutter exists, and takes an average value of the data within the block; The data editing means 6 edits blocks in the same direction based on the average value output by the clutter detection means and the detection result of the clutter detection means, and the timing control means 7 controls the operation timing of each means.

Next, regarding the operation of the embodiment shown in Fig. 1, Figs. 2(a) to (g)
).

Analog radar low video outputted from a receiver of a radar device is converted into a digital signal with conventional fineness in a digitizing means 1 by a sampling clock 8 provided from a timing control means 7.

This digital signal is divided in the block division means 2 into blocks a, block b, block C, and block d in the distance direction by a block division signal 9 supplied from the timing control means 7, as shown in FIG. 2(a). The data is compiled into blocks, and a block number is added to the data storage means 3. It is output to the data averaging means 4 and the clutter detection means 5.

The data storage means 3 stores data according to block numbers.

The data averaging means 4 calculates the data within the block, for example,
As shown in FIG. 2(b), data a to h in block b are averaged and the average value is output to the data editing means 6.

The clutter detection means 5 sets a threshold level higher than the amplitude level of the noise signal as shown in FIG. 2(c) for the input data for each block,
If the continuity of a signal exceeding that level is greater than the spread of the target signal in the distance direction, that block is determined to be an area where a clutter signal exists.

At this time, if a signal exceeding the threshold level exists continuously but is smaller than or equal to the continuity of the target signal, for example, in the case of a prominent noise signal or target signal, this is regarded as a clutter signal. As a result, it is determined that it is not a clutter signal. In this way, Figure 2 (d
) is output to the data editing means 6 for each block.

The data editing means 6 collects the signals of each block by fine sampling of the data storage means 3 as shown in FIG. 2(e) and the data averaging means 4 as shown in FIG. 2(f).
However, if there is no clutter, the data storage means 3 is output based on the clutter determination signal 10 outputted from the clutter detection means 5 shown in FIG. 2(d).
If there is clutter, the output of the data averaging means 4 is used to edit and output the data as shown in FIG. 2(g).

〔Effect of the invention〕

As explained above, in the digital transmission of radar-low video, the present invention uses averaged data when clutter exists when digitizing radar-low video. This has the effect of reducing line capacity and reducing line usage fees and other maintenance costs.

Furthermore, since the method compresses data by selecting only the clutter signal, it is possible to remove the data redundancy of conventional methods and perform efficient transmission without reducing the resolution of the important target signal. effective.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG.
) to (g) are explanatory diagrams of the operation of the embodiment of FIG. 1, FIG. 3(a) is an explanatory diagram of the radar video including clutter, and
FIG. 4B is an explanatory diagram of a radar-processed video with clutter suppressed, and FIG. 4 is an explanatory diagram of sampling of a conventional radar video. DESCRIPTION OF SYMBOLS 1... Digitization means, 2... Block division means, 3... Data storage means, 4... Data averaging means, 5... Clutter detection means, -6... Data editing means, 7... Timing control means, 8... Sampling clock, 9... Block division signal, 10... Clutter determination signal.

Claims (1)

[Claims] 1. A radar video compression system for digitally transmitting a radar video signal to a display device, which converts analog radar video into a digital signal for each sweep video as video in the same direction. block dividing means for dividing the digital signal into data blocks by dividing the digital signal into data blocks; the block dividing means; data storage means for storing data for each block; a clutter detecting means that determines whether or not a clutter signal exists at predetermined azimuth increments and outputs only the data of the block where the clutter signal exists; data averaging means for taking an average value and replacing each data with one average value; data in units of blocks outputted from the data storage means; data regarding the average value outputted from the data averaging means; and the clutter detection. data editing means that collects, edits, and outputs blocks for each same direction based on the detection results of the means; A radar video compression system comprising: timing control means for controlling output timing. 2. Clutter detection by the clutter detection means is determined based on a signal that exceeds a predetermined threshold level and whose continuity is greater than the spread of the target signal in the distance direction. 2. The radar video compression system of claim 1.