JP2000162305A - Radar device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To distinguishably display tracks of a plurality of mobiles respectively by sequentially displaying position data at different time points which have been sequentially stored with time intervals shorter than a predetermined time interval along a passage of time. SOLUTION: A receiving part 30 outputs, as a received waveform, a reflected wave from another object which is emitted and received by an antenna 1, and a coordinate conversion circuit 32 converts it into a coordinate system according to a display screen for outputting as position data. A PPI memory 33 successively updates for each output of new position data with rotation of the antenna 1 to store the data only of the newest screen, and a data update circuit 45 of a storage means 4 sequentially stores this position data. A combination circuit 52 of a display means 5 combines and outputs the position data occasionally output from the PPI memory 33 and position data output from a plot memory 44, and a display device 53 displays it. At this time, a data read circuit 51 outputs the position data of the plot memory 44 with display time intervals shorter than plot interval time along a passage of time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radar apparatus having a function of displaying the position of another moving body or structure, such as a marine radar apparatus.

[0002]

2. Description of the Related Art Conventionally, a radar device mounted on a marine vessel or the like has a function of displaying the position of a moving body, a structure, or the like (hereinafter referred to as a target) of another marine vessel or the like on a screen. And
It is useful for preventing collisions with each other. If the target displayed on the screen is a moving object such as a ship,
Knowing the direction and speed of the target is important for preventing collision. Therefore, the following two methods, (1) echo plot method and (2) echo trail method, are used to add and display information such as the traveling direction and speed of other moving objects on the screen of the radar device. is there. (1) Echo plot method The data on the display screen is stored in the memory every time the data is updated or at predetermined intervals, and these are displayed simultaneously with the current data in thin gradations. Therefore, the past position of the other ship is displayed in a linear or dot-like manner depending on the traveling direction and speed so as to trail from the current position. (2) Echo trail method This is basically the same as the echo plot method, except that the oldest data after a certain period of time has been deleted. Alternatively, the gradation is displayed with a lighter gradation as the elapsed time is longer. Therefore, unnecessary past trajectories do not increase too much on the screen as in the echo plot method.

[0003]

However, the above-mentioned echo plot method and echo trail method have the following problems. (1) Echo plot method (a) Since past data is added sequentially without erasing,
The problem that unnecessary past trajectories increase too much on the display screen. (b) In the sea area where the tracks of multiple ships intersect, the problem is that each track cannot be distinguished. (c) The problem is that it is difficult to intuitively recognize the speed of another ship because it is a static display of the ship. (2) Echo trail method The above problem (a) is solved, but problems (b) and (c) are not. Another problem is that a large memory capacity is required and the circuit becomes complicated.

Accordingly, the present invention provides a radar apparatus which can display the trajectories of a plurality of other moving objects in a distinguishable manner, and also displays the moving speed of each moving object as well as the current position thereof. It was made for the purpose.

[0005]

According to the present invention, there is provided a radar apparatus having position data output means for sequentially outputting position data of a target, wherein the position data output from the position data output means is output from the position data output means. A storage means for sequentially storing at predetermined time intervals, and when the number of stored position data reaches a predetermined number, erases the oldest position data stored each time new position data is stored; Position data at a plurality of different times stored in the storage means, at a time interval shorter than the predetermined time interval,
A display means for sequentially displaying the stored time is provided, so that the trajectory of the target is dynamically displayed.

Accordingly, a plurality of past display data are sequentially displayed along a lapse of time at shorter time intervals than when new position data is stored in the storage means, so that the trajectory appears to be moving. . Therefore, the moving direction and the moving speed of the target can be grasped intuitively. Even when the trajectories of a plurality of targets intersect, it is possible to prevent confusion by the position data displayed in order.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A radar apparatus according to the present invention will be described below in detail with reference to the drawings showing an embodiment.

In FIG. 1 showing the entire configuration of a radar apparatus according to the present invention, reference numeral 1 denotes an antenna which rotates at a fixed period, 2
Denotes a transmitting unit, and 30 denotes a receiving unit. A radar wave emitted from the transmitting unit 2 is radiated from the antenna 1, and a reflected wave alive upon returning to another target is received by the antenna 1, amplified and demodulated by the receiving unit 30, and output as a received waveform. Is done. An A / D conversion circuit 31 converts the received waveform into a digital signal, a coordinate conversion circuit 32 converts the digital signal into a coordinate system corresponding to a display screen based on the converted digital signal, and outputs the coordinate system as position data. Is a PPI memory for sequentially updating the position data output from the coordinate conversion circuit 32 each time the antenna rotates and outputting new position data, and storing only the latest one screen. Antenna 1, transmitting unit 2, receiving unit 30, A / D
The conversion circuit 31, the coordinate conversion circuit 32, and the PPI memory 33 implement a position data output unit. Numeral 4 denotes storage means, a plot memory 44 for storing the position data stored in the PPI memory 33 for N screens, and a plot memory 44 for sequentially storing the position data stored in the PPI memory 33 for each plot interval time. And a data update circuit 45 for storing. Here, if the position data for N screens is already stored in the plot memory 44, the oldest position data is deleted and the stored data is updated.

Reference numeral 5 denotes display means, and the PPI memory 3
3 and the plot memory 4
A combining device 52 for combining and outputting the position data output from the combining device 4, a display device 53 for displaying the combined data output from the combining circuit 52, and the plotting device for each display interval time shorter than the plotting interval time. A data readout circuit 51 is provided for outputting the position data stored in the memory 44 from the plot memory 44 to the synthesizing circuit 52 in order as the stored time elapses. Here, the position data stored in the PPI memory 33 is output to the synthesizing circuit 52 as needed.

The operation of the data updating circuit 45 and the data reading circuit 51 in the radar device having the configuration shown in FIG. 1 will be described with reference to the flowchart shown in FIG. Step S
In step 1, the plot interval time K and the display interval time L are set to predetermined times. However, K>
L. The number N of screens that can be stored in the plot memory 44 is four. In step S2, the display interval timer t is set to an initial value 0. In step S3, the area designation number m of the plot memory 44 is set to an initial value 0. In step S4, a plot interval timer T is set to an initial value 0. In step S5, the position data of the PPI memory 33 is stored in the plot memory 4
4 to the area M (m). In step S6,
The area designation number m of the plot memory 44 is changed to m + 1. In step S7, the plot interval timer T is compared with the plot interval time K.
The process proceeds to step S8, and if T <K, the process proceeds to step S9.

In step S8, if it is the last area, the process returns to step S3.
Return to 4. In step S9, if it is the last area, the process proceeds to step S10; if not, the process proceeds to step S11.
Proceed to. In step S10, the area designation number n to be read is set to an initial value 0, and the flow advances to step S12. In step S11, the area designation number n to be read is set to m, and the flow advances to step S12.

In step S12, the position data of the area M (n) of the plot memory 44 is output to the synthesizing circuit 52. In step S13, it is checked whether or not the display interval timer t has exceeded the display interval time L. If not, the process proceeds to step S14. If it has passed, the process proceeds to step S15. In step S14, the plot interval timer T is compared with the plot interval time K, and T ≧ K
If T <K, the process proceeds to step S8, and returns to step S12.

In step S15, the display interval timer t is returned to the initial value 0. In step S16, the area designation number n to be read is changed to n + 1. In step S17, the area designation number n to be read becomes the last four. Returns to step S14. Area designation number n to be read is 4
, In step S18, the initial value is returned to 0 and the process returns to step S14.

In this manner, the position data for four screens are stored in steps S4 to S8, respectively, as shown in FIGS.
At 8, the latest position data shown in FIG. 3 e stored in the PPI memory 33 is superimposed on the same screen, and
The images are sequentially displayed like g, h, and i. By displaying in this manner, the displays D (0), D (1), D (2), and D (3) of the target at the past time are sequentially displayed on the same screen over time. Therefore, it is possible to intuitively grasp the moving direction and the moving speed of the target.

A setting means for automatically setting the plot interval time K and the display interval time L according to the range may be provided. The display method of the plot memory is such that the position data from the past position data to the last stored position data are displayed in order from j, k, l, m as shown in FIG. 3, and the last stored position data is displayed. After the screen is cleared,
It may be displayed again from the past display data.

When writing the position data of the PPI memory to the plot memory, a plurality of gradations are not written at all,
If only one arbitrary gradation is written, the memory capacity can be saved. When the position data in the plot memory is displayed, the displayed gradation may be changed according to the elapsed time.

[0017]

As described above, according to the present invention, the position data output from the position data output means of the radar device is stored for a plurality of screens, and the plurality of position data stored in the storage means are stored. Is displayed in order from the oldest position data to the newest position data, so that the trajectory of the target can be dynamically displayed. Can be recognized. Further, as described above, since the moving direction and the moving speed of the target can be intuitively recognized, it is possible to intuitively predict the future position, which is effective in preventing accidents such as collisions. Further, an effect that the amount of memory used can be reduced as compared with the echo trail method can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a configuration of an embodiment of a radar device according to the present invention.

FIG. 2 is a flowchart of a main part of the operation of the radar device.

FIG. 3 is a diagram showing a display example of a display screen of the radar device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 antenna 2 transmission unit 30 reception unit 31 A / D conversion circuit 32 coordinate conversion circuit 33 PPI memory 1, 2, 30, 31, 32, 33 position data output unit 4 storage unit 44 plot memory 45 data update circuit 5 display unit 51 Data readout circuit 52 Synthesis circuit 53 Display device

Claims (1)

[Claims] In a radar apparatus provided with position data output means for sequentially outputting position data of a target, position data output from said position data output means is sequentially stored at predetermined time intervals. Storage means for erasing the oldest position data stored each time new position data is stored when the number of position data obtained reaches a predetermined number;
Display means for sequentially displaying the position data at a plurality of different times stored in the storage means at a time interval shorter than the predetermined time interval in accordance with the lapse of the stored time. Characterized in that the trajectory is dynamically displayed.