JPH1194931A - Radar equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform display after scanning correlative processing also to improve its discriminating ability even if a target moves at high speed. SOLUTION: A target designation part 17 for designating a target desired to be observed out of the targets included in image data stored in an image memory 5 and performing scanning correlative processing. A tracking and position prediction correction part 18 including a tracking prediction circuit 181 for tracking the designated target and predicting the position at the time point of receiving in the new image data of the target and a position correction circuit 182 moving and correcting the position of the designated target of the image data from the image memory 5 to a prediction position and output as position corrected image data is provided. Scanning correlative processing of new image data stored in an image memory 4 and the position corrected image data is performed by an image data processing part 6, and it is shown on a display 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a radar device,
In particular, the present invention relates to a radar device mounted on a ship configured to perform a correlation process between a newly received video signal and a video signal received before the video signal to display an image.

[0002]

2. Description of the Related Art A radar device mounted on a ship stores video signals for one rotation of the antenna (one scan) in order to improve the sea surface reflection at short distances and the ability to identify targets in rain and snow clutter. In advance, an image is displayed by performing a correlation process with a video signal for the next rotation of the antenna.

In such a configuration, the positions where sea surface reflection and rain and snow clutter occur are random at each scan, so that correlations cannot be obtained and are not displayed, whereas the target to be observed has almost the same position. (In the case of a stopped state or a low-speed movement) and the correlation is obtained, the information can be displayed on the display screen and identified. The above-described correlation processing is generally called scan correlation processing.

FIG. 3 shows a block diagram of a typical conventional example of such a radar apparatus. The radar device includes a transmitting / receiving unit 1 that emits microwave radio waves at predetermined time intervals from an antenna rotating at a predetermined speed, receives a reflected wave from a target by the antenna, and outputs the received signal as a video signal, and a setting unit. A noise removing circuit 2 for removing noise of a video signal from the transmitting / receiving section 1 based on the threshold value of the level, and an A / D for converting an analog video signal from the noise removing circuit 2 into digital video data. The conversion circuit 3 receives the transmission trigger TXT from the transmission / reception unit 1 and receives the distance clock generation circuit 1
1. Write address Aw1 for coordinate conversion based on distance data RD generated by distance counter 12 and azimuth signal DS from antenna azimuth control unit 8 and based on azimuth data DD generated by azimuth clock generation circuit 9 and azimuth counter 10. And the read address A
r1 for generating a read address, an address switching circuit 14 for switching between a write address Aw1 and a read address, and an output. A first video memory 4 which converts video data into X, Y coordinate type video data, stores the data for one rotation of the antenna (for one scan), and reads out the read data in accordance with a read address Ar1;
Video data Vs for one scan after scan correlation processing
cr is the write address A from the address generation circuit 16x.
The second video memory 5 for writing and storing according to w2 and reading according to the read address Ar2, the video data for one scan from the first video memory 4, and 1
A video data processing circuit 6 for performing scan correlation processing with video data from the video memory 5 before scanning and outputting the result as video data Vscr;
A display unit 7 for displaying an image of a target or the like by cr is provided.

[0005] Next, an image display based on video data including noise caused by sea surface reflection, rain and snow clutter, and the like and a target will be described with reference to FIGS. 4 and 5. In this case, each scan timing of the target and the noise is represented by T, its position is represented by i, and the target is represented by Si (T) and the noise is represented by Ni (T) (where T = 1, 2, 3,..., i = 1,2,3, ...
…). Further, with respect to the levels (signal and noise intensities) of the target Si (T) and the noise Ni (T), in a general radar, the signal intensity is often expressed by two or more bits, for example, 4 bits. , The signal strength ranges from 0 to 1.
Although represented by a value of 5, here, the description will be made as the simplest 1-bit data. That is, the signal strength is “0”
(No signal and noise) or "1" (Signal and noise).

Here, the target Si in each scan is
Since (T) and noise Ni (T) exist and occur at respective positions, their levels (hereinafter, referred to as signal strength including noise) are “1”. That is, when these signal intensities are also displayed using the above symbols, Si (T) =
1, Ni (T) = 1.

In a radar apparatus having no scan correlation processing function, these targets Si in each key scan are used.
(T), since the image of the noise Ni (T) is displayed as it is, the display is as shown in FIG. 4. If noise occurs near the target, the target cannot be identified.

On the other hand, in the radar apparatus having the scan correlation processing function (the example in FIG. 3), if the target Si (T) does not move (including the case of extremely low speed), the signal is output at the same position in each scan. The intensity becomes “1”, and the signal intensity after the scan correlation process also becomes “1”, so that the signal Ni is displayed on the display screen. The signal intensity after the processing becomes "0" and is not displayed. This state is shown in FIG. 5 (noise not displayed is indicated by a broken line).

Here, the scan correlation processing will be described. As an example of the content of the scan correlation processing, new video data (read from the first video memory 4)
It is assumed that an AND operation is performed with the video data up to one scan before the video data, and the following mathematical expression is obtained when the mathematical expression is displayed. Si (T) * = Si (T) · Si (T−1) * where * indicates that scan correlation processing was performed.
Indicates that an AND operation is performed. The first scan immediately after the operation of the radar device is not scan-correlated because there is no video data of the scan correlation partner, but by setting all data levels of the second video memory 5 in the initial state to “1”, two scans are performed. Scan correlation can be performed from the eye. FIG. 5 does not show the scan immediately after the operation of the radar apparatus.

[0010]

In the conventional radar apparatus described above, new video data from the first video memory 4 and video data up to one scan before this video data (from the second video memory 5 The image display is configured to display an image based on image data that has been subjected to scan correlation processing with the image data. Therefore, while sea surface reflection and rain / snow clutter are not displayed, they do not move or move slowly (relative speed with the ship itself). ) Are displayed, and the identification ability of these targets can be improved. However, when the moving speed of the targets (relative speed with respect to the own ship, the same applies hereinafter) increases, the targets of the new video data can be identified. Since the position and the position of the target in the video data up to one scan before this video data are different, no correlation is obtained, and as shown in FIG. 6, the target is not displayed (broken line display), and the target is not displayed. Another capability there has been a problem that interfere with the safe navigation of the ship decreases.

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, it is an object of the present invention to remove sea surface reflection and rain / snow clutter by correlation processing, and at the same time, to display a target moving at a high speed, thereby improving its identification ability. It is an object of the present invention to provide a radar device capable of contributing to safe navigation of a ship.

[0012]

The radar apparatus according to the present invention comprises:
In order to achieve the above-mentioned object, the following configuration is provided. (B) a transmitting / receiving section that radiates microwave radio waves at predetermined time intervals from an antenna rotating at a predetermined speed, receives a reflected wave from a target through the antenna, and outputs it as a video signal; (C) a video signal stored in the reception video memory and included in the video signal up to one rotation before the antenna and specified. By tracking the target, the position of the target at the time of reception in the video signal stored in the received video memory is predicted,
The position of the specified target is moved and corrected to the predicted position, and the target tracking / outputting is output as a position corrected video signal.
(D) a video signal processing circuit that performs correlation processing between the video signal from the received video memory and the position-corrected video signal from the target tracking / position prediction correction means and outputs the video signal; Display unit that displays images according to the output signal of the processing circuit

Further, the target tracking / position prediction correcting means stores a signal processing result storing video memory for storing and outputting an output signal of the video signal processing circuit, and a video signal stored in the received video memory. A target specifying unit that specifies a predetermined target among the targets included in the video signal up to one rotation before the aerial, and tracking the target specified by the target specifying unit to track the target A tracking prediction circuit that predicts a position at the time of reception in a video signal stored in a reception video memory; and a position of a target specified by the target specification unit in an output signal from the signal processing result storage video memory. Is corrected to the position predicted by the tracking prediction circuit, and is output as the position-corrected video signal.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention relates to a video signal up to one revolution before the antenna, specifically, a correlation process performed by a video data processing circuit with respect to a new video signal stored in a received video memory. A specified one of the targets included in the specified video signal is specified and the specified target is tracked, and at the same time, the position of the specified target at the time of reception in the new video signal is predicted. A target tracking / position prediction correcting means for correcting the movement of the position of the specified target to the predicted position and outputting the corrected position as a position-corrected video signal is provided, and the output from the target tracking / position prediction correcting means is provided. The image is displayed by a video signal that has been subjected to a correlation process between the corrected position-corrected video signal and the new video signal.

With this configuration, even if the target moves at a high speed, the position of the designated target of the video signal up to one rotation before the antenna changes to the position at the time of reception in the new video signal. Since the movement has been corrected to the vicinity, the result of the correlation processing is “correlated”, and the target is displayed as an image. On the other hand, since sea surface reflection and rain and snow clutter are removed by the correlation processing, the ability to identify the target is improved, which contributes to the safe navigation of the ship.

[0016]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of the present invention. This embodiment is different from the conventional radar apparatus shown in FIG.
The video data from the video memory 5 (the video memory for storing the signal processing result) is supplied to the video data processing circuit 6 as it is, and the new video data from the first video memory 4 (the received video memory) In contrast, in the present invention, the video data from the second video memory 5, that is, the new video data, up to one rotation before the antenna (one scan before) is used in the present invention. Out of the targets included in the video data, the target specifying unit 17 specifies the target, and the specified target is tracked by the tracking prediction circuit 181. The position at the time of reception is predicted, and the video data from the second video memory 5 is moved and corrected by the position correction circuit 182 to the position of the specified target to the predicted position described above. Requires the video data, in that the supplied to the video data processing circuit 6 to perform the scan correlation process between the position corrected image data and the new video data.

In this embodiment, the tracking prediction circuit 18
Reference numeral 1 denotes tracking of a specified target based on the scan correlation-processed video data obtained by the video data processing circuit 6, the distance data RD from the distance counter 12, and the direction data DD from the direction counter 10. Further, the tracking / position prediction correction unit 1 is combined with the tracking prediction circuit 181 and the position correction circuit 182.
It is set to 8. The address generation circuit 16 for supplying the write address and the read address to the second video memory 5 has a slightly longer generation timing than the conventional address generation circuit 16x in consideration of the operation time of the position correction circuit 182. Is different. The target tracking / position prediction correcting means described in claim 1 and the like includes a second video memory 5, an address generation circuit 16, a target designation unit 17, and a tracking / position prediction correction unit 18.

Next, the scan correlation processing in this embodiment will be described. First, since position correction and the like are not performed on noise and an unspecified target, scan correlation processing similar to that of the conventional example is performed. The formula for the specified target is different from the conventional example. Therefore, the contents of the scan correlation processing according to this embodiment (the present invention) can be expressed by the following equations. Si (T) [*] = Si (T). [Si-1 (T-1)
[*]] Here, [*] indicates a scan correlation with the position-corrected video data, and [Si-1 (T-1) [*]] indicates
This indicates that the position of the video data after the scan correlation processing has been corrected to the specified target until one scan before. That is, the position-corrected video data.

Next, a scan correlation processing operation and a display image of this embodiment will be described with reference to FIG.
In FIG. 2, the three display images on the left side are images that are actually displayed on the display unit 7, and the two display images on the right side are not displayed on the display unit 7 or the like, but are displayed by the position-corrected video data. It is an assumed image. First, T =
Target S1 (1) of video data of scan 1 specified
Then, scan correlation processing is performed with the position-corrected video data [S0 (0) [*]] up to one scan before,
It is assumed that the result is displayed as the target S1 (1) [*] (signal strength “1”).

Next, the target S1 after the scan correlation processing is performed.
(1) With respect to [*], the position of the target is moved and corrected to the position predicted by the tracking prediction circuit 181, and the position-corrected target [S1 (1) [*]] is temporarily displayed as an image. Then, it becomes as shown in the upper right (signal strength “1”). Since the position of this target [S1 (1) [*]] is corrected to the vicinity of the position at the time of receiving the target S2 (2) in the next scan of T = 2, the position of the signal strength "1" When the scan correlation process with the target S2 (2) is performed, the target S2 (2) [*] after the scan correlation process with the signal strength “1” is also displayed as an image (middle stage on the left). Hereinafter, similarly, the target S3 (3) [*] after the scan correlation processing is displayed as an image with the signal strength “1” (lower left side).

On the other hand, noise is not displayed as in the conventional example (FIG. 5 and the like). Therefore, even if the target to be observed (that is, specified) is a target moving at high speed, it can be clearly displayed, and the ability to identify the target can be improved and contribute to the safe navigation of the ship. . In particular, the effects of the present invention are extremely large for ships whose speed is increasing.

In this embodiment, the target of the video data from the second video memory 5 is designated, the position of the target is corrected to move to the predicted position, and the scan correlation processing with the new video data is performed. However, this is because, in the conventional example shown in FIG. 3, the video data up to one scan before the new video data is stored in the second video memory 5, and this is used. Is the simplest, and thus has such a circuit configuration, and the present invention is not limited to this circuit configuration.

For example, for the video data that has been subjected to the scan correlation processing by the video data processing circuit 6, the target is directly designated and the movement is corrected to the predicted position, and this is stored in the memory, and the next scan correlation processing is performed. The circuit configuration can be used. In short, it is important to specify the target of the video data up to one scan before and correct the movement to the predicted position, and perform scan correlation processing with new video data. The point in time at which the video data is stored may be determined in consideration of the simplicity of the circuit configuration, the relationship with peripheral circuits, and the like. However, considering the accuracy of the predicted position, the first video memory 4
Until new video data is stored in the new video data, the distance data RD and the azimuth data D of the target of the new video data are stored.
Since D also contributes to the position prediction, it is preferable that the correction of the movement of the target to the predicted position is performed immediately before the scan correlation processing (that is, the configuration of the present embodiment).

[0024]

As described above, according to the present invention, a target to be observed is specified from among targets included in a video signal one scan before a new video signal, and this target is tracked. The position of the target at the time of reception in the new video signal is predicted, and the position of the target specified at the predicted position is moved and corrected to obtain a position-corrected video signal. Even if the target is moving at high speed, the target to be observed is clearly displayed, and the sea surface reflection and the rain and snow clutter are reduced even if the target moves at high speed. Since it is removed, its discrimination ability is improved, and there is an effect that it can contribute to the safe navigation of ships, especially ships whose speed is increasing.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a diagram showing noise and target display images for explaining the operation and effect of the embodiment shown in FIG. 1;

FIG. 3 is a block diagram illustrating an example of a conventional radar device.

FIG. 4 is a diagram illustrating a display image of noise and a target when the conventional radar apparatus does not have a correlation processing function.

FIG. 5 is a diagram showing a noise and a display image of a target moving at an extremely low speed or in a stopped state for explaining the operation of the radar apparatus shown in FIG. 3;

FIG. 6 is a diagram showing a display image of noise and a moving target for explaining a problem of the radar device shown in FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transmission / reception part 2 Noise removal circuit 3 A / D conversion circuit 4, 5 Video memory 6 Video data processing circuit 7 Display part 8 Antenna azimuth control part 9 Direction clock generation circuit 10 Direction counter 11 Distance clock generation circuit 12 Distance counter 13 Scan converter Reference Signs List 14 address switching circuit 15 read address generation circuit 16, 16x address generation circuit 17 target designation section 18 tracking / position prediction correction section 181 tracking prediction circuit 182 position correction circuit

Claims (2)

[Claims] 1. A radar apparatus having the following components. (B) a transmitting / receiving section that radiates microwave radio waves at predetermined time intervals from an antenna rotating at a predetermined speed, receives a reflected wave from a target through the antenna, and outputs it as a video signal; (C) a video signal stored in the reception video memory and included in the video signal up to one rotation before the antenna and specified. By tracking the target, the position of the target at the time of reception in the video signal stored in the received video memory is predicted,
The position of the specified target is moved and corrected to the predicted position, and the target tracking / outputting is output as a position corrected video signal.
(D) a video signal processing circuit that performs correlation processing between the video signal from the received video memory and the position-corrected video signal from the target tracking / position prediction correction means and outputs the video signal; Display unit that displays images according to the output signal of the processing circuit 2. The image processing apparatus according to claim 1, wherein the target tracking / position prediction correcting means stores a signal processing result storage video memory for storing and outputting an output signal of the video signal processing circuit, and a video signal stored in the reception video memory. A target specifying unit that specifies a predetermined target among the targets included in the video signal up to one rotation before the aerial, and tracking the target specified by the target specifying unit to track the target A tracking prediction circuit that predicts a position at the time of reception in the video signal stored in the reception video memory;
A position at which the position of the target specified by the target specifying unit in the output signal from the signal processing result storage video memory is moved and corrected to the position predicted by the tracking prediction circuit, and is output as the position corrected video signal. 2. The radar device according to claim 1, comprising a correction circuit.