JPH01297578A - Radar plotting device - Google Patents

Abstract

PURPOSE:To obtain a continuous wake display and to easily understand a target position by inferring the target position whose tracking is impossible, when tracking of the target has become impossible temporarily. CONSTITUTION:A radar equipment detects a target position in the periphery of its own vessel at a prescribed time interval, and a target memory stores a position of a target which has been detected. Also, the position of the target which has been detected is plotted in an image display use memory and a wake of the target is displayed. Subsequently, a target moving azimuth calculating means and a target moving speed calculating means calculate a moving azimuth and a moving speed of the target from time series data of the target position of plural points which have been derived, and a target position inferring means infers the present position of the target from the target position which has been stored in a target memory, an elapsed time after it has been stored in the target memory, the target moving azimuth and the moving speed. Moreover, an inferred target position plotting means plots the target position which has been inferred, in the image display use memory. In such a way, even if the target cannot be captured by a radar equipment and tracking becomes impossible, the target position can be inferred.

Description

Detailed Description of the Invention (a) Industrial Application Field This invention is a radar plotting system that automatically captures and tracks targets such as other ships detected by radar and displays their positions on a display screen. Regarding equipment.

(bl Prior Art) A conventional radar plotting device uses a radar device to detect the position of a target object such as another ship at regular time intervals, and plots the position of the target object sequentially on a display screen to track the target object's wake. is displayed automatically.

(e) Problems to be Solved by the Invention In order to display the trajectory of a target from target echoes detected by a radar device, it is necessary to combine echoes from previously or previously detected targets and newly detected The target must be acquired sequentially based on the echoes from the target. In conventional radar pro-7 tracking devices, when a target object such as another ship enters the shadow of an island or a huge ship and a few seconds have elapsed, it issues an "untrackable" warning and abandons tracking. After that, even if other ships came out of the shadows,
Assuming that a new ship has appeared, they begin tracking it separately.

Therefore, the conventional radar plotting apparatus has the following disadvantages.

■If tracking becomes impossible, the track up to that point will disappear, or even if it does not disappear, the track of the target that has reappeared will become discontinuous.

■It is difficult for the observer to judge the identity of the target before tracking became impossible and the target that is being tracked again. At night and? Especially when it's li.

■If another vessel with an identification code cannot be tracked and is re-tracked, the observer will need to attach the identification code again.

■If it becomes impossible to track the target, the collision predicted closest approach distance (C
Danger calculations such as PA) and time of closest approach (TCPA) cannot be performed.

An object of the present invention is to provide a radar plotting device that solves the above-mentioned conventional problems by estimating the position of the target that cannot be tracked when the target is temporarily unable to be tracked. .

(Means for Solving Problem d1) The radar plotting device of the present invention comprises: a radar device that detects the positions of targets around its own ship at regular time intervals; a target memory that stores the positions of the targets; A radar plotting device is equipped with a means for plotting the positions of targets sequentially detected by a radar device in an image display memory, and the moving direction and direction of the target are determined from time-series data of multiple target positions sequentially determined. A target moving direction calculating means and a target moving speed calculating means for calculating a moving speed, a target position stored in the target object memory, an elapsed time after being stored in the target object memory, and the target object movement. A target position estimating means for estimating the current position of the target from the azimuth and the target moving speed, and an estimated target position plotting means for plotting the estimated target position on the image display memory. It is a feature.

(e) Effect In the radar plotting device of the present invention, the radar device detects target positions around own ship at regular time intervals,
The target object memory stores the position of the target object detected by the radar device. Furthermore, the position of the detected target is plotted in the image display memory to display the track of the target. The target position estimation means calculates the moving direction and moving speed of the target from the time series data of the target position of multiple points, and the target position estimating means calculates the target position stored in the target memory and the target position stored in the target memory. The current position of the target is estimated from the elapsed time since storage, the target moving direction, and the target moving speed. Further, the estimated target position plotting means plots the estimated target position on an image display memory.

As a result, even if the radar device cannot capture the target and cannot track it, the position of the target can be estimated, so that tracking can be continued and risk calculations such as CPA and TCPA can be performed. Furthermore, since the estimated target position is plotted, continuous track display is possible.

(f) Embodiment FIGS. 1 to 6 are diagrams relating to the radar plotting device of the present invention, in which FIG. 1 is a plot diagram, FIG. 2 is a display example, and FIG. 3 is shown in FIG. 1. FIG. 4 is a flowchart showing the processing procedure of the CPU 20. Further, FIG. 5 shows a target object table configured in the RAM 14, and FIG. 6 shows a tracking target table configured in the RAM 22.

Figure 2 is an example of displaying the track of another ship being followed.
- B is the route tracked and displayed by the radar device, and B - C is the section where it was impossible to capture other ships and tracking was done by guessing. Point D is the position where it became possible to capture another ship and re-tracking started, and the line between CD and D shows the deviation between the estimated position at the time of starting re-tracking and the actual position. Point E is the current position of the other ship, and F is a vector representation representing the course and speed of the other ship. Moreover, (A1) is an example of display of the identification code of another ship. Each section of the track is displayed in a different color to clarify its meaning.

In FIG. 1, a pulse generating circuit 1 is a circuit that generates a timing pulse for emitting radio waves from an antenna 3, and a transmitting circuit 2 is triggered by this pulse signal to cause the antenna 3 to emit radio waves. Also, this pulse signal is C
It is given as an interrupt signal (interrupt 1) for P[Jl 1. The receiving circuit 4 is a circuit that receives reflected waves received by the antenna 3. The distance counter 5 is reset by a pulse generated from the pulse generation circuit 1, and counts a value corresponding to the distance from the reflecting object using the pulse generated from the pulse generation circuit 16. An antenna drive circuit 6 is a circuit that rotationally drives the antenna 3, and a direction counter 7.
is a circuit that counts a value corresponding to the direction of the antenna (antenna azimuth with respect to the bow direction), and is an azimuth pulse generator built in the antenna drive circuit 6 (for example, generates a pulse every time it rotates once). Count the pulses generated by the device. The reference direction detection circuit 15 is a circuit that detects that the antenna is directed toward the bow direction of the ship, and at that timing resets the direction counter 7 and
Generates an interrupt signal (interrupt 3) for 1. An adder 17 adds to the count value of the direction counter 7 a value of the bow direction with north as a reference, which is output from a direction detector 18 such as a gyro compass or a magnetic compass. Therefore adder 1
7 outputs the antenna direction based on north.

The distance register 8 is a register that sets the distance when detecting a reflected wave from a specific distance.

The window comparator 9 is a circuit that detects whether or not the value output from the distance counter 5 is within a certain width before and after the value set in the distance register 8.
If they match, the gate circuit 10 generates the output signal of the window comparator 9 as an interrupt signal (interrupt 2) to the CPU I when the output signal is generated from the receiving circuit 4.

The CPU II performs processing according to a program written in the ROM 13 in advance. The RAM 14 stores target data θ and a distance counter 5 that stores distances and directions of multiple targets.
The distance data r output from the distance register 8 is inputted, and the distance data is outputted to the distance register 8.

The CPU 20 performs processing for displaying the track of the winter target based on the contents of the target table received from the CPU II, and the program is written in the ROM 21 in advance. The RAM 22 is a memory that includes a tracking target table including the positions (latitude, longitude), moving direction, and moving speed of a plurality of targets. 23 is an image display memory, and the display control circuit 24 reads the contents of this memory and displays it on the CRT.
A display signal is generated for 25. A positioning device 27 for positioning the own boat is connected to the I10 boat 26, and the CPU 20 determines the own position at a necessary time.

FIG. 5 shows the configuration of the target table provided in the RAM 14, and as shown in the figure, the winter target is a target object table.

Distance, direction, and data on whether or not to update are stored. Here, the target object is a number assigned when a new target is captured, and the update status data is the update state of the data after the target has been captured and distance and direction data have been written to this table. This is data that represents

FIG. 6 shows the configuration of a tracking target table configured in the RAM 22. Each target is a target patient.

Data on latitude, longitude, moving direction, moving speed, and acquisition status are stored, but these data are created based on the data in the target table shown in Figure 5, which is updated at regular intervals. Ru. Note that the data indicating whether or not the target is captured indicates whether the target is being captured or estimated.

Now, the processing procedure of the CPUI 1 shown in FIG. 1 is as follows.

First, when a pulse signal is generated from the pulse generating circuit 1, the interrupt processing shown in FIG. 3(A) is performed. That is, the CPU reads the antenna direction → θ, reads out the target object data in the direction within θ±Δθ from the target object table shown in FIG. 5, and sets the distance data ri in the distance register 8 (nl-' n2→n3).

The window in the distance direction constituted by the distance register 8 and the window comparator 9 shown in FIG.
If a target exists within the window in the angular direction selected by the process n2 in A), an interrupt signal (interrupt 2) is generated. At this time, the CPU 1 reads the distance r of the target object from the distance counter 5 (n4), as shown in FIG. 3(B). Next, the position of the read target is updated at n2. That is, the distance data is set to r that was read this time, and the azimuth data is set to the azimuth θ that was read at n1 above.

Also, update status data for the updated target data is set (n5).

After that, when the antenna goes around once, an interrupt signal (interrupt 3) is generated from the reference direction detection circuit 15 shown in FIG.
The UI l performs the processing shown in FIG. 3(C). First, all data in the target table is transferred to CI) U3O, and then all data on whether or not to update the target table is reset (
n6-”n7).

The CPU 20 performs processing according to the procedure shown in FIG. First, while the target table data is not transferred from the CPU II, the own ship position is measured (nlO→n1)). If there is data transfer for the target table, enter all the data and
The contents of the tracking target table shown in the figure are updated. Specifically, i, which represents the target target position, is reset (n13).
. Next, if the updated presence/absence data of the target indicated by i in the input target table continues to be captured from the set state section, the distance, direction, and own ship position of the target input this time will be updated. The position of the target (latitude, longitude) is calculated based on the target position, and the moving direction and speed of the target are calculated by comparing the previous target position and the target position determined this time, and the target object table for tracking is calculated. Update the data (n14-
"n15).Furthermore, create track display data (n16)
).

For targets whose updated data has been reset among the target table data, the current target position is estimated based on the target's previously determined moving direction and moving speed, and the tracking target is Update the position data (latitude, longitude) of the target table and reset the capture status data (n
20). Next, create estimated track display data (n2
1).

If the updated presence/absence data of the newly input target data is set when the captured data in the tracked target table is in the reset state, it means that the target has been captured again, and the captured target position is calculated. Then, the position data (latitude, longitude) of the tracking target table is updated, and the capture presence/absence data is set (nl?-n18). Next, create track display data (between C and D in Figure 2) between the final estimated target position and the re-titt capture position (n19)
By performing the above processing for all targets, each data in the tracking target table is updated (n22→n23)
.

In addition, based on the content of the tracking target data shown in Figure 6, risk calculations such as collision predicted closest approach distance (CPA) and closest approach time (TCPA) are performed in the same way as before, and it is determined that the predicted collision distance (CPA) and time of closest approach (TCPA) are below the predetermined value. It is also possible to configure the system to issue an alarm when the alarm occurs.

(G1 Effect of the invention As described above, according to this invention, even if a target such as another ship enters the shadow of a small island or a huge ship, the moving direction, speed, and elapsed time of the target that have already been determined can be determined. Since the current position of the target is estimated based on the following, the following effects are achieved.

■Continuous track display is obtained, making it easy to determine the target position.

- It becomes easy to determine the identity of a target that cannot be tracked once and a target that has been tracked again.

■By automating re-tracking from the estimated position of the target, it becomes unnecessary to assign a new identification code.

■Danger calculations are possible even during periods where detection is impossible.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a radar plotting device that is an embodiment of the present invention, Fig. 2 is a display example of the same device, and Fig. 3 (
A) to (C) are flowcharts showing the processing procedure of the CPU 1 in the same device, and FIG. 4 is a flowchart showing the processing procedure of the CPU 20, respectively. FIG. 5 shows a target object table configured in the RAM 14, and FIG. 6 shows a tracking target table configured in the RAM 22.

Claims (1)

[Claims] (1) A radar device that detects the positions of targets around the own ship at regular time intervals, a target memory that stores the positions of the targets, and an image display of the positions of the targets sequentially detected by the radar device. In a radar plotting device equipped with a means for plotting in a memory, a target movement direction calculating means and a target movement that calculate a movement direction and a movement speed of a target from time series data of a plurality of target positions obtained sequentially. a speed calculating means; estimating the current position of the target from the target position stored in the target memory, the elapsed time since the storage in the target memory, the target moving direction, and the target moving speed; A radar plotting device comprising: a target position estimation means for estimating the estimated target position; and an estimated target position plotting means for plotting the estimated target position on the image display memory.