JPH03252583A - Automatic radar plotting device - Google Patents

Abstract

PURPOSE:To accurately grasp the state of disappearance and carry on subsequent monitoring by storing the disappearance position and/or identification code of a disappearing material, and displaying and confirming its contents upon occasion. CONSTITUTION:A target tracking part 8 receives code setting signals of other ships through a control part 5, extracts a ship to be tracked from a radar echo signal, and sends its position (relative position with this ship), a future predicted position, etc., to an other-ship wake processing part 9. The processing part 9 calculates and stores the longitude, latitude, absolute speed, absolute course, and vectors of the target ship according to target-ship information and information on this ship sent through the control part 5. If the ship is mistracked in a monitor area, an alarm is generated and the disappearance position, identification code, etc., are stored in a disappearing ship display field and also displayed 10. Further, when the ship in the disappearing ship display field appears on the screen, a tracking part 8 sends its identification code to the processing part 9, which erases the identification code in the disappearing- ship display field and displays a new and an old wake on a display part 10.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to an automatic radar plotting device that captures and tracks a target from radar echo signals and automatically displays its trajectory.

(b) Prior Art Conventionally, a so-called ARPA (automatic radar plotting device) has been used as a navigational aid device or a device for monitoring other ships.

Conventional automatic radar plotting equipment manually or automatically captures targets (ships, buoys, islands, etc.) detected by radar, and then automatically tracks them to obtain the target's identification code, position, ship speed, course, and other information. Graph the wake ink or character.
indicate.

However, the tracked target may be lost (disappeared) due to various reasons listed below.

■When the target cannot be detected by radar because it is too far away, or because it is behind an island or a huge ship.

■Multiple targets approach and the radar echoes become one
When it is considered a target.

■When ARPA is unable to track the target because it suddenly turns or accelerates or decelerates suddenly.

In this way, when ARPA is unable to track a target, conventionally it outputs a warning sound such as a buzzer for several seconds to several tens of seconds, and displays a blinking mark indicating the position of the missing target and a vector display indicating the ship's speed and course. After informing the observer (crew) of the disappearance, the character display of the position and identification code of the lost object and the graphic display of the mark and vector of the lost object are erased, and the track is displayed graphically. It is configured so that only

(C) Problem to be Solved by the Invention However, unless the observer is in front of the display device during the output of the alarm sound for several seconds to several tens of seconds, it is impossible to know the position or identification code of the missing object. Even if a watchman is present, if multiple targets disappear almost simultaneously, it is difficult to accurately identify all the disappeared targets. This may mean that the target that the observer thinks is being tracked has already disappeared, or that the identification code, position, speed, and course of the target at the time of disappearance are unknown. There was a risk that monitoring would be interrupted and a collision could occur. On the other hand, if the situation at the time of the disappearance can be grasped, the observer can continue monitoring by increasing the gain of the radar or predicting the current position of the target.

SUMMARY OF THE INVENTION An object of the present invention is to provide an automatic radar plotting device that stores the situation at the time of disappearance of a lost target and can confirm the situation as needed.

(d) Means for Solving the Problems The automatic radar plotting device of the present invention includes a target extracting means for extracting a target to be tracked from a radar echo signal, a target extracting means for extracting a target to be tracked from a radar echo signal, a target extracting means for predicting the position of the target, a target tracking means for continuously identifying the tracked target; a tracked target track storage unit for storing the track of the tracked target; The apparatus includes a missing target storage means for storing an identification code for specifying a disappeared target, and a display means for displaying the stored contents of the tracked object track storage means and the lost target storage means in graphics or characters.

te1 Effect In the automatic radar plotting device of the present invention, the target extraction means extracts the target to be tracked from the radar echo signal, and the target tracking means predicts the position of the target and continuously tracks the same target. Tracking is performed by identifying the The track of the tracked target is sequentially stored by the tracked target track storage means,
When it is detected that tracking of a target object has failed, the disappearing position of the target object and/or the identification code for specifying the disappeared target object are stored in the lost target storage means. The stored contents of the tracked target track storage means and the lost target storage means are then displayed graphically or in characters by the display means.

Since the vanishing position and/or identification code of the vanishing object are stored in this way, the situation at the time of the disappearance of the vanishing target can be reliably grasped by displaying the contents as needed.

(fl Embodiment) Before giving a detailed explanation of an automatic radar plotting apparatus which is an embodiment of the present invention, the configuration of each part and modifications thereof will be described.

[1] Information display when a target disappears (1) As shown in Figure 3 (A), the other ship's track, position, speed, and course are graphically displayed as the other ship's track, other ship mark, and other ship vector, respectively. do. Also, the identification code of the other ship is displayed as a character near the other ship mark. When the other ship disappears, the other ship's track, the other ship's mark,
It is made clear that this target has disappeared by changing the color or shape of the other ship vector and identification code.

(2) Display the disappeared targets as a character chart as shown below.

F612:13 136°15.78'E 30°0
1.54'N10.5KT 142.5°A312:16 136°15.10'E 30°0
2.06'N5.9KT Perform 329.8°. Monitored areas include the following:

In front of own ship... (Moves on the map) Within the shipping lane... (Fixed on the map) No-fishing area... (Fixed on the map) In territorial waters... (Fixed on the map) Outside territorial waters... (Fixed on the map) (Fixed) [3] Deletion of character or graphic display at the time of re-acquisition When a target that had disappeared from behind an island appears again,
If the same identification code as before the disappearance is set and the object is re-captured, the information on the corresponding lost object among the disappeared objects shown in (2) above will be erased. In addition, the graphic display of the missing object shown in (1) above may be deleted or not.
Good too. Alternatively, the old and new tracks may be displayed connected in a straight line.

An embodiment of the present invention will be explained under the following circumstances (11) A ship (another ship) is used as an example of a target, and a no-fishing area is used as an example of a monitoring area.

(2) Graphically display ships lost in no-fishing areas.

(3) Only the identification code of the information on ships that disappeared within the no-fishing area will be displayed in the pre-disappearance display column.

(4) Ships shall be captured manually. (Automatic acquisition will be described later.) (5) When re-acquired, the old and new tracks are connected and displayed.

A block diagram of the entire device is shown in FIG. First, values indicating the scale, vector length (time corresponding to the vector length), latitude and longitude of the center of the screen, which are set by keyboard operations, are input to the ship's track processing section 1, respectively. Own ship track processing unit 1 displays scale, vector length, and own ship position (described later) as characters, and latitude lines and longitude lines created based on scale and screen center values as characters and graphics. The track processing unit converts the coastline and monitoring area information previously stored in the internal memory of the ship's track processing unit 1 into information that is displayed graphically based on the value and scale at the center of the screen. 2. If the area in front of the ship is to be monitored, graphic display information of the area to be monitored is obtained based on the ship's position, heading angle, and scale.

In addition, the own ship's track processing unit 1 sequentially stores and accumulates position information indicating the latitude and longitude of the own ship sent from a navigation device that measures the own ship's position, such as Loran, Detsuka, or GPS, in an internal memory. At the same time, it is converted into information for graphically displaying the ship's track and marks on the generated nautical chart, and is sent to the track processing unit 2 every time position information is sent from the navigation device.

In addition, the azimuth angle (
own ship's azimuth (course) information sent from an azimuth measuring device that measures the angle relative to north, and own ship's own ship's own ship's azimuth (course) information sent from a ship speed measuring device such as an electromagnetic log or Doppler log that measures ship speed. The ship speed information, vector length, and scale are converted into graphic display information of own ship's vector, and this is sent to the track processing section 2. Furthermore, the input trunk ball value (indicating the position on the screen) is converted into latitude and longitude values from the screen center value and scale, and the value and mark (+) are converted into character and graph ink display information. It is converted and sent to the track processing section 2.

In addition, the ship's track processing unit 1 also provides the control unit 5 with information on the monitoring area,
The scale, vector length, screen center value, and own ship information (own ship position, ship speed, course, and track) are sent constantly or at regular intervals. Furthermore, the own ship's track processing section 1 controls the control section 5.
The relative position of the trackball mark from the own ship for manual acquisition, which will be described later, and the identification code set by the keyboard operation are sent to the target tracking unit 8 through the target tracking unit 8. In addition,
The relative position of the trackball mark from the own ship is determined by the control unit 5.
It is calculated from the latitude and longitude values of the trunk ball mark and the latitude and longitude of the own ship.

The track processing unit 2 stores color CRT screen information (
It has a refresh memory and displays the information from own ship's track processing section 1 in predetermined colors and marks on the color display 4.
In addition to converting the color CR1 screen information corresponding to T and writing it into the refresh memory, the synchronization signal generator 11
A signal is read out from the refresh memory according to a synchronization signal from , and the video signal is sent to the mixer 3 . Also,
The synchronization signal generator 11 also sends synchronization signals to the display section 10 and the color display 4.

The mixer 3 combines a plurality of video signals, including the own ship's information and chart information from the track processing section 2, and the radar image and other ship's information (described later) from the display section 10. The color display 4 is a raster scan type display that combines video signals such as absolute position, absolute ship speed, absolute course, track, and identification code and sends it to the color display 4. Receive signal and CRT
It displays nautical chart information, graphic ink characters of your own ship and other ships coded in several different colors, and radar images.

The above has described the display method mainly for the own ship, but next we will describe the display method for radar images.

The radar echo, bow marker, directivity angle of the radar antenna, and transmission trigger signals sent from the radar are all received by the radar interface 6.

The radar interface 6 performs preprocessing such as interference removal, sea surface reflection suppression, and rain and snow reflection suppression on the radar echoes, and then quantizes them at a predetermined period (the period is constant and not linked to the scale). 1 in internal buffer memory
Accumulate one swipe. Further, the preprocessed radar echo is read out at an appropriate timing and sent to the radar image processing section 7 and the target tracking section 8. At the same time, the directivity angle of the radar antenna with respect to the bow of the ship is also converted into, for example, a digital value and sent to the radar image processing section 7 and the target tracking section 8.

When calculating the position of an object, such as another ship, from radar echoes, it is normally displayed in a polar coordinate system of the distance from the own ship and the directivity angle of the radar antenna relative to the bow, but this device uses a raster scan method. Since the north amplifier is displayed on the display 4, it is necessary to convert it to an orthogonal coordinate system with north as the reference. Also, when displaying normal radar images, simply set the bow direction or due north direction at the top of the screen, set the own ship's position (center of the radar image) at the center of the display screen, and convert the polar coordinate system to a rectangular coordinate system. However, in this device, it is necessary to display the image in a superimposed manner on the nautical chart generated by the ship's track processing unit 1, so it is necessary to correct the screen position to match the nautical chart. In other words, if a nautical chart is drawn using the Mercator projection, it is necessary to correct the length in the latitude and longitude directions according to the latitude and longitude indicating the own ship's position. This is performed by the control section 5 and the radar image processing section 7. That is, since the control unit 5 receives the own ship's position from the own ship's track processing unit 1 at all times or at regular intervals, based on this, it calculates the latitude line direction and the correction value for the current own ship position. The ratio of the length in the longitude direction and the center point of the CRT display screen and the center point of the radar image at the scale value of the generated nautical chart (same as own ship position)
Both the deviation in the latitude line direction and the deviation in the longitude line direction (center offset amount) are calculated and sent to the radar image processing section 7.

The radar image processing unit 7 determines the azimuth angle (angle with respect to north) of the radar antenna from the own ship's heading angle from the control unit 5 and the directivity angle of the radar antenna with respect to the bow sent from the radar interface 6. , this is converted from a polar coordinate system to a rectangular coordinate system taking into account the scale value, and further correction is performed in the latitude and longitude line directions based on the ratio of the center offset amount from the control unit 5 and the length in the latitude and longitude line directions. Then, the write address of the refresh memory of the display section 10 is calculated. In addition, the radar image processing unit 7 converts the radar echo sent from the radar interface 6 into CR1 screen information in one color shade depending on its intensity, and displays this CR1 screen information and the above-mentioned write address information. 10 and written into the refresh memory of the display unit IO.

Next, we will discuss how to display the tracks of other ships.

In the same way as displaying the radar image described above, preparations for displaying the wake of another ship are made in the control unit 5. That is,
The control section 5 sends the own ship's heading angle from the own ship's track processing section 1 to the target tracking section 8, and also sends the own ship's heading angle from the own ship's track processing section 1 to the other ship's track processing section 9.
Own ship information, monitoring area, and vector length are sent as parameters for displaying other ship's track marks and vectors on the chart generated by own ship's track processing unit 1.

The target tracking unit 8 stores the preprocessed radar echo information from the radar interface 6 described above for multiple sweeps in an internal buffer memory, and reads the radar echo from the radar memory at an appropriate timing. ,
Removes echoes such as noise.

Then, the position of the extracted radar echo is stored in another memory as the distance and azimuth from the own ship.

However, it does not extract all echoes after noise and other echoes have been removed, but only those specified by the monitor.

The above-mentioned designation by the observer is carried out as follows. First, the observer manually enters the identification code of the other ship he wants to monitor, then operates the trunk ball to place the trackball mark on the radar echo of that ship on the screen, and presses the code entry key. As a result, the code setting signal is sent to the target tracking section 8 through the ship's track processing section 1 and the control section 5. When the target tracking unit 8 receives this code setting signal, it extracts radar echoes near the trackball mark based on the relative position of the trackball mark. At this time, other ship identification codes are also stored.

The extraction of the radar echoes described above is repeated in accordance with the sending timing from the radar interface 6 to obtain information for one scan worth of echoes. Furthermore, this process is performed for multiple scans, and for each scan, the position of the echo indicating the relative position to the own ship's position in the past scan stored in the memory and the relative position of the echo in the current scan are calculated for each echo. The position (relative position) of other ships is extracted by comparing with the other ships, and the relative speed and relative course of each other ship is calculated. The relative position of each other ship in the future is estimated from the calculated relative speed and relative course, the radar echoes in the vicinity are sampled, a more accurate position is extracted, and the relative speed and relative course are calculated again. At this time, if there is no radar echo in the vicinity, it is considered a tracking error. Thereafter, this process is repeated to track the position of each other ship. Furthermore, the target tracking unit 8 adds individual identification codes to the relative position information of each other ship being tracked through the above-mentioned processing, and sends the information to the other ship track processing unit 9 at each scan or every fixed scan. do.

The other ship track processing unit 9 receives the relative position, relative speed, relative course, identification code, presence or absence of tracking errors of each other ship from the target tracking unit 8, and own ship information, scale value, and vector length from the control unit 5. Based on this information, the latitude, longitude, absolute speed, absolute course, and vector of each other ship are calculated and sequentially stored in an internal memory in a format that can be classified for each other ship. Furthermore, in order to display information on other ships in graph ink and characters as individual other ship information on the nautical chart generated by own ship's track processing unit 1, the CRT of color display 4 is displayed in predetermined colors and marks.
Converts to color CR7 screen information compatible with the display unit l
Send to O.

In addition, since the other ship's track processing unit 9 recognizes the position, speed, course, tracking error, etc. of each other ship as described above, The blinking of the lamp, the sound of the buzzer, the color of the track, the mark, and the vector disappeared when another ship missed tracking for several consecutive scans within the monitoring area. CR7 screen information is generated to change the color to indicate the color (yellow).

If another ship shown in the disappeared ship display column reappears on the screen and is captured with the same identification code, the target tracking unit 8 sends the same information to the other ship track processing unit 9 as shown in the disappeared ship display column. Since the identification code is sent, the other ship's track processing section 9 erases the corresponding identification code in the lost ship display column and displays the new and old tracks in a connected manner as shown in FIG.

FIG. 3(B) is an example of a display when another ship F6 disappears in the state shown in FIG. 3(A), and is subsequently re-acquired and sailed a distance indicated by the track ■. As shown in the figure, the old track ■ and the new track ■ are connected and displayed with a straight line ■. In this case, ■, ■, and ■ may all be displayed in orange, or ■ and ■ may be displayed in yellow, and ■ may be displayed in orange.

The display unit 10 stores the CRT screen information of the radar image from the radar image processing unit 7 and the CRT screen information of other ship information and disappearance information from the other ship track processing unit 9 at the corresponding address of each refresh memory, These stored contents are read out in synchronization with the synchronization signal from the synchronization signal generator 11 and sent to the mixer 3 as video signals of radar images, other ship information, and disappearance information.

As described above, the mixer 3 combines video signals such as own ship information and chart information with video signals such as radar images and other ship information. As a result, the CRT of color display 4
Nautical chart information, information on own ship and other ships coded in several different colors, and radar images are displayed.

A display example of the color display 4 is shown in FIG.

In this figure, all images of nautical chart information, own ship and other ships' information, missing target information, and radar images are displayed in a north-light display, and the own ship's track, own ship mark, and own ship vector are each displayed in white. The own ship vector indicates the course and speed of the own ship, and its hector vertex indicates the position 3 minutes later when the vector length is 3 minutes and the current ship speed and course are maintained. The character display of own ship information is the latitude of own ship position,
The longitude is displayed at the top right of the screen. As a graphic display of other ship information, the other ship's track, other ship's mark, and other ship's vector are each displayed in orange, and as a character display of other ship's information, an identification code (Al, 36) is displayed near the other ship's mark. be done. In addition, the wake of other ships that disappeared,
The marks and vectors of other missing ships are displayed in yellow. The mark of the other ship that disappeared represents the vanishing point, and the vector shows the ship's speed and course just before the ship disappeared. Further, the identification code (B6) of the other ship is displayed near the missing other ship mark. It will be displayed on the screen. Nautical chart information is displayed as a solid light blue line, and boundaries of no-fishing areas (monitored areas) are displayed as broken red lines in graphic ink. Further, the latitude lines and longitude lines are each graphically displayed in blue, and the value of each line is displayed in characters at the periphery of the screen. Additionally, the trackball mark is displayed in yellow graph ink, and its value is displayed in characters at the bottom right of the screen. In addition, vector length, scale, etc. are displayed in characters. In addition to these information displays, radar images of coastlines and ships are displayed superimposed in green.

The example shown above uses manual acquisition in which the target to be tracked is manually extracted, but automatic acquisition is also acceptable. The processing contents of each part shown in the figure differ as follows.

Target Tracking Unit 8 (For manual acquisition) Tracks only radar echoes of other ships designated by the observer. At that time, the observer attaches an identification code to each tracked target. Therefore, the trackball relative position, identification code, and code setting signal from the control unit 5 are required.

<When automatically capturing> All points or within a specified range (for example, 5 points from own ship)
Track radar echoes of other ships (within 0 miles). At that time, for example, information that can be classified by a series of numbers (unrelated to the identification code) is automatically attached to the extracted echoes. No identification code is attached at the time of automatic capture (it is attached by the other ship's track processing section 9). Therefore, the trackball relative position, identification code, and code setting signal from the control unit 5 are unnecessary.

Other ship's track processing unit 9 When manually capturing> All other ships being tracked are displayed on the display 4 with their tracks, marks, vectors, and identification code materials. Since the identification code is already attached, the relative position of the trackball from the control unit 5,
No identification code and code setting signal are required.

<When automatically capturing> Displays all other ships being tracked with their tracks, marks, and hectors. Identification codes will be displayed on other vessels designated by the watchdog with trackball marks.

At this time, the "classifiable information" of other ships is replaced with the identification code set by the observer. (Only other ships with identification codes are monitored for disappearances within the monitoring area.) Normally,
"Classifiable information" is not displayed. Furthermore, in order for the observer to attach an identification code, the trunk ball relative position, identification code, and code setting signal from the control unit 5 are required.

(g1 Effect of the invention According to this invention, a target that has disappeared due to failure in tracking is automatically memorized, and its contents can be confirmed on the display. Therefore, the situation when the target disappears can be accurately determined. Once this information has been identified, monitoring can be continued through subsequent manual operations by the monitoring staff.

FIG. 2, a block diagram of the rosoting device, is an example of the overall display of the color display in the same device. Figure 3 (A),
(B) is an example of displaying other ship information.

Claims (1)

[Claims] (1) A target extraction means for extracting a target to be tracked from a radar echo signal; a target tracking means for predicting the position of the target and continuously identifying the same target; and a track of the tracked target. a tracked target trail storage means for storing a tracked target; and a lost target storage means for storing a disappeared position of a target and/or an identification code for specifying the disappeared target when it is detected that tracking of the target has failed. and display means for displaying the stored contents of the tracked object track storage means and the lost target storage means in graphics or characters.