JPH03264880A - Automatic apparatus for radar plotting - Google Patents

Abstract

PURPOSE:To know the occurrence of transfer and the situation thereof without fail and to continue monitoring of a target to be tracked, by a manual operation or the like, by detecting the transfer automatically and by displaying the information on the transferred target. CONSTITUTION:A target tracking element 8 adds an identification code to each relative position information on another ship being tracked and supplies it to an another ship track processing element 9 in each scan or in each prescribed scanning. Since the track processing element 9 recognizes the current and past positions of the other ship, it compares the area T minutes before with the current position and determines whether or not the current position exists in the area T minutes before. When it does not exist therein for several successive scans, it is judged that transfer has occurred, and an alarm is issued by flicker of a lamp, the sound of a buzzer or the like, while a target name is displayed in a transferred target display section, a color of the track of the target being changed from orange to yellow. As the result, the target before transfer can be tracked again by checkup of the content of display or a manual operation of an apparatus by a watchman.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application This invention relates to an automatic radar plotting device that captures and tracks a target object from a radar echo signal 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. Graphic or character track
indicate.

The so-called α is a method for automatically tracking targets detected by radar.
-There is a β tracker method. This is as follows: 1) Calculate the difference between the predicted position and the actual observed position, smooth this variation, and set the current target position (smoothed position).

■Similarly, calculate the velocity (smoothed velocity) from the previous smoothed position to the current smoothed position, consider the future velocity of the target object, and predict the future position from the current smoothed position of the target object. .

By repeating steps 20 and 2, the target is automatically tracked. That is, the range predicted as the future position of the target object is set as a gate, and the target object that enters this gate next time is regarded as the target object.

(C) Problem to be solved by the invention However, when there is another target near the target being tracked,
If another target enters the tracking gate, the other target may be mistakenly tracked instead of the target being tracked, resulting in so-called transfer. At this time, since ARPA cannot detect by itself that a transfer has occurred, no alarm is output.

This means that although the observer (crew) thinks that Vessel A, which is the target of surveillance, is being automatically tracked and that it is being displayed on the display screen, sometime during the process, an unknowing (transfer) occurs. )
What happens is that we are tracking Vessel B. Therefore, in this case, it will be impossible to monitor Vessel A, and Vessel A's track will not be recorded, so for example, how Vessel A moved and acted as a fishing act, whether it did not exceed the 200 nautical mile line, etc. becomes incomprehensible.

An object of the present invention is to provide an automatic radar plotting device that automatically detects the occurrence of transfer and displays the target.

(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 that continuously identifies a tracked target; a tracked target track storage unit that stores a track of a tracked target; and a transfer object that detects a target that is not at a predicted position after a scheduled time or at a scheduled time as a transferred target. The apparatus includes a target detection means, and a display means for displaying the stored contents of the tracked target track storage means and information regarding the transferred target in graphics or characters.

(e) Operation 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 detects the same target. Tracking is performed by continuous identification. The tracked target track storage means sequentially stores the tracks of the tracked target. The transfer target detection means detects a target that is not at the predicted position after the scheduled time or at the scheduled time as a transfer target. The display means displays the stored contents of the tracked target track storage means and information regarding the transferred target in graphics or characters.

Since the transfer target object is automatically detected and the transfer target object is displayed in this way, it becomes possible to track the target object before transfer again by checking the display contents by the observer or manually operating the device.

(f) Embodiment Before giving a detailed explanation of an automatic radar plotting apparatus which is an embodiment of the present invention, the l1ltc of each part and its modification will be described.

First, the following method can be cited as a method for detecting transfer.

(1) In the case of a moving target, set a line or area, set the time or time until it crosses the line or enters the area, and when the scheduled time elapses or the scheduled time is reached. A transfer is considered to have occurred when the target does not cross the line or enter the area.

For example, the method for setting a line or area is as follows (A
There are three methods: ) to (C).

(A) Method of setting a line or area on a map As shown in the upper part of FIG. 4 (A), a line is set on the planned course of the target object to pass after or at the scheduled time. In the example shown in the figure, the line is set to pass through line 1 at 9:15, line 2 at 9:30, and line 3 at 9:45.

Further, as shown in the lower part of FIG. 4(A), an area to be reached after the scheduled time or at the scheduled time is set on the map. In the example shown in the figure, the area will be reached within 35 minutes and 50 minutes later.
It is assumed that the vehicle will reach area 2 in 1 minute and reach area 3 in 65 minutes.

(B) Method of setting by distance and direction from own ship Figure 4 (B)
), set the position of the target after the scheduled time has elapsed or at the scheduled time using the distance and direction from the own ship. In the example shown in the figure, the line is set to be crossed at 9:20.

(C) Method of setting by distance and direction from target Figure 4 (C
), the position of the target object after the scheduled time has elapsed or at the scheduled time is set using the distance and direction from the current target object.

In the example shown in the figure, the position of Ship A is set to arrive within the area in 10 minutes.

According to the methods (A) to (C) above, it is possible to detect sudden changes in targets such as sudden turns, sudden acceleration, and sudden deceleration, which are limited to transfer targets.

Note that the length and position of the line and the size and position of the area may be constant, or may be changed depending on the movement and size of the target and the movement of the own ship. Further, the number of lines and areas may be plural, and the lines may be straight or curved. Further, the area can take various shapes such as fan-shaped, circular, square, or rectangular. Furthermore, the required time may be set as the time from the current time, or may be set as the required time between lines or areas.

(2) In the case of a stationary target If the target is a stationary target such as a buoy, an area is set on the map or centered around the target's current position, and if the target moves outside of that area, the area will not change. deemed to have occurred.

In the embodiments of the present invention described below, the above (1)-(C
), that is, the transfer is detected by setting the moving target based on the distance and direction from the target. In addition, the capturing method will be manual. (Automatic acquisition will be described later.) The specific setting method is as shown in FIG. The area is fan-shaped, the time is the time required from the current position, and the direction of the fan shape is the path of the target at that time.
The size of the fan shape is made proportional to the speed of the target at that time. At this time, the required time is T (minutes), and the fan-shaped azimuth width is Δθ (degrees).
Set to . If the speed of the target at this time is V (mile 7 minutes), R+ΔR/2=VT ΔR=ct −VT+Rmin Here, α and Rmin are constants.

Note that Δθ may be a function of V.

In this way, the block diagram of the entire device constantly compares the area position T minutes ago with the current position, outputs a transfer warning when the current position does not exist within the area, and displays the transfer target in characters and graphics. is shown in Figure 1.

First, the scale, vector length (time corresponding to the vector length), latitude of the center of the screen, and
The value indicating the longitude and the trackball mark position set by the trackball operation (the position on the screen, the unit is a dot. However, in order to display the character, the position is set in latitude and longitude, and the trackball mark position is set by the trackball operation.) When sent to
The position is converted by the own ship track processing unit 1 as a relative position (azimuth and distance) from the own ship. ), Own ship information i (Own ship information i includes position, ship speed, and course; position is sent from navigation equipment such as Loran, Denka, GPS, etc., ship speed is sent from ship speed measurement such as electromagnetic log, Doppler log, etc.) and the course is sent from a heading angle measuring device such as a gyro compass or a magnetic compass.) are sent to the ship's track processing section 1, respectively.

Own ship's track processing section 1 converts the following contents into information for displaying graphics and characters based on the above information and coastline information previously stored in internal memory, and sends the converted information to track processing section 2. .

■Character display of scale, vector length, own ship position, ■Graphic and character display of latitude and longitude lines created from scale and screen center value, ■Coastline created from scale, screen center value, and coastline information (1) Scale, value at the center of the screen, and own ship information ii (including the own ship's track obtained by storing the own ship's position in the internal memory of the own ship's track processing section 1 and the above own ship information i);

) graphical ink display of own ship's mark, vector and track; ■ graphic and character display of trackball mark (+) position created from scale, screen center and trackball mark position The ship track processing unit l sends the scale, vector length, screen center value, and own ship information i to the control unit 5 at all times or at regular intervals. Furthermore, the own ship's track processing section 1 sends the trackball mark position, identification code, and code setting signal to the target tracking section 8 and other ship's track processing section 9 for manual acquisition, which will be described later, through the control section 5. Send α, Rmin, T, and Δθ set using the keys, respectively.

The track processing unit 2 has a refresh memory for storing color CRT screen information, and displays the information from the ship's track processing unit 1 in predetermined colors and marks on the color display 4.
The synchronizing signal generator 11 converts the information into color CRT screen information corresponding to T and writes it into the refresh memory.
A signal is read out from the refresh memory 5 according to a synchronization signal from , and the video signal is sent to the mixer 3 . Further, the synchronization signal generator 11 also sends a synchronization signal to the display section IO and the color display 4.

The mixer 3 combines a plurality of video signals, including video signals such as own ship information and chart information from the track processing section 2, and video signals such as radar images and information on other ships, which will be described later, from the display section 10. are combined and sent to the color display 4.

The color display 4 is a raster scan type display that receives the video signal from the mixer 3 and displays chart information on the CRT.
It displays graphics, links/characters, and radar images of own ship and other ships.The above describes the display method mainly for own ship, but next we will explain how to display radar images.

The radar echo, bow marker, radar antenna finger angle, 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/snow reflection suppression on the echoes, and then quantizes the echoes at a predetermined period (the period is constant and not linked to the scale) and internally One sweep is stored in the buffer memory. 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 it is displayed on the display 4 in a north-up orientation, 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 information in a superimposed manner on the nautical chart created by the ship's track processing section 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 center point of the CRT display screen and the center point of the radar image based on the length ratio in the longitude direction and 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. Further, the radar image processing unit 7 converts the radar echo sent from the radar interface 6 into CRT screen information in one color (or several colors may be used) depending on the intensity of the radar echo, and converts the radar echo sent from the radar interface 6 into CRT screen information. The information and the above-mentioned write address information are sent to the display section 10 and written into the refresh memory of the display section 10.

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 i and vector length are sent as parameters for displaying other ship track marks and vectors on the chart generated by own ship track processing unit l.

The target tracking unit 8 stores the preprocessed 1-da echo information from the radar interface 6 described above for multiple sweeps in the internal buffer 7 memory, reads out the radar echo from this buffer memory at an appropriate timing, and eliminates noise. Remove echoes such as

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 wishes to monitor, then operates the trackball to place the trackball mark on the radar echo of that ship on the screen, and presses the code hole 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. Thereafter, this process is repeated to track the position of each other ship. Further, the target tracking unit 8 adds individual identification codes of 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, and identification code of each other ship from the target tracking unit 8 and own ship information i, m scale value, hector length, and Δθ, T from the control unit 5.
, Rmin, and α, the latitude, longitude, absolute speed, absolute course, and hector 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 the information of other ships as graphics and characters as individual other ship information on the chart created by own ship's track processing section 1, predetermined colors and marks are used to display the information on the CRT of the color display 4. The information is converted into color CRT screen information and sent to the display section 10.

In addition, since the other ship track processing unit 9 recognizes the current and past positions of each other ship as described above, it compares the area T minutes ago with the current position and Determine whether the current position exists. If it does not exist for several consecutive scans, it is determined that a transfer has occurred, and a warning is issued with flashing lamps and a buzzer, and the name of the target is displayed in the transfer target display field, and the track of the target is displayed. Changes the color from orange to yellow.

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 ships information from the other ship track processing unit 9 at the corresponding address of each refresh memory. The contents are read out in synchronization with the synchronization signal from the synchronization signal generator 11 and sent to the mixer 3 as a video signal of radar images and other ship information.

As described above, the mixer 3 mixes video signals such as own ship information and chart information, and video signals such as radar images and other ship information. As a result, the CRT of color display 4
Chart information, information about own ship and other ships, and radar images are displayed.

A display example of the color display 4 is shown in FIG. This figure is an example in which all of the nautical chart information, information about own ship and other ships, transfer targets, and radar images are displayed in north-up true motion. As shown in the figure, the own ship's track, own ship mark, and own ship vector are each displayed in white as a graphic ink display of own ship information. The own ship vector indicates the course and speed of the own ship, and the vertex of the vector indicates, for example, when the vector length is 3 minutes, the position after 3 minutes when the current ship speed and course are maintained. As the character display of own ship information, the latitude and longitude of the own ship position are displayed in the upper right corner of the screen. In addition, as shown in the same figure, other ships' tracks,
The other ship mark and other ship vector are each displayed in orange, and an identification code (Al, 36) is displayed near the other ship mark as a character display of other ship information. In addition, the wake of another ship detected as a transfer target is displayed in yellow (the solid line is orange before the transfer, and the broken line is yellow after the transfer).
The ship's mark, vector, and identification code (B6) are each displayed in orange. In addition, the identification code (B6) of the target detected as a transfer target is displayed in the transfer target display column.
) is displayed.

Additionally, the nautical chart information is graphically displayed in light blue, the latitude lines and longitude lines are each graphically displayed in blue, and the values of each line are displayed as characters on the periphery of the screen. Additionally, the track pole mark is graphically displayed in yellow, and its value is displayed in characters at the bottom right of the screen. Other character displays include vector length and scale. 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 During manual acquisition> Tracks only radar echoes of other ships specified by the observer. At that time, the observer attaches an identification code to each tracked target. Therefore, the trackball 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 position from the control unit 5,
No identification code and code setting signal are required.

Other ship's track processing unit 9 <When capturing manually> Displays all other ships being tracked on the display 4 with their tracks, marks, vectors, and identification codes. Since the identification code is already attached, the trackball position, identification code, and code setting signal from the control unit 5 are not required.

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

At this time, the "classifiable information" of other ships is replaced with the identification code set by the observer, and the other ships that have been replaced with the identification code take over. Normally, "classifiable information" is not displayed. In addition, the trackball position, identification code, and code setting signal from the control unit 5 are required for the observer to attach the identification code.

(g) Effects of the Invention According to this invention, transfer is automatically detected and information regarding the transfer target is displayed, so that the occurrence of transfer and its situation can be reliably grasped, and subsequent monitoring personnel can It becomes possible to continue monitoring the target object to be tracked by manual operation using .

FIGS. 4A to 4C are diagrams illustrating examples of settings for detecting transfers used in the embodiment. FIGS. 4A to 4C are diagrams illustrating main examples of settings for detecting transfers.

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 object track storage means for storing the following; a transfer target detection means for detecting a target that is not at the predicted position after a scheduled time or at the scheduled time as a transfer target; and the memory contents of the tracked object track storage means and the above. An automatic radar plotting device comprising display means for displaying information regarding moving targets in graphics or characters.