JP2001264415A - Detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a correct radar image irrespective of the turn of a ship. SOLUTION: The rotational angular velocity of a radiation unit in an antenna 1 is controlled according to the steering angular velocity of the ship so that the rotational angular velocity in the detection signal transmission direction in the coordinate system fixed to the surface of the earth is constant. Thus, under a circumstance in which the ship (more generally, a mounted moving body) is turned, the write on a memory to provide the two-dimensional storage space is achieved following the detection signal transmission method in the coordinate system fixed to the earth surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a detection device mounted on a moving body.

[0002]

2. Description of the Related Art A radar device mounted on a ship is an example of a detection device mounted on a moving body. The ship radar device wirelessly detects the existence, position, behavior, and the like of another object, for example, another ship or land (hereinafter, "target"), and displays the result on a screen of a display such as a CRT. It is a device that displays as video, safe and efficient operation of ships,
It contributes to the realization of operations.

[0003] There are various display forms of radar images on a display screen. Among them, a PPI for displaying the presence or absence of a target around the own ship in a two-dimensional manner, that is, in a form similar to a map or a chart. Display is frequently used. When performing PPI display, a frame memory that provides a two-dimensional storage space corresponding to the screen of the display is prepared. Further, a write address corresponding to the two-dimensional position of the target is specified, and a received signal, that is, an echo signal related to a reflected wave from the target is written on the frame memory. Then, this data is read out in synchronization with the screen scanning of the display.

Here, the echo signal is associated with the direction in which the detection signal was transmitted and the time from the transmission of the detection signal until the reflected wave is obtained. Since the latter represents the distance from the ship to the target, it can be said that the echo signal is associated with the position of the target expressed in a polar coordinate format. When writing an echo signal to the above-mentioned frame memory, a write address is generated in accordance with the position of a target associated with the echo signal, and the write address is designated and the echo signal is written. As a result, on the frame memory, data indicating the target existing around the own ship is stored according to the two-dimensional position of the target, etc., and displayed on the screen of the display that performs display based on the data on the frame memory. Means that a radar image indicating the presence or absence of a target around the own ship is displayed by PPI.

[0005] Further, among the information necessary for generating a write address to the frame memory, the direction of transmission of the detection signal is obtained by providing a member for detecting the angle of the antenna for transmitting the detection signal. be able to.
Since the angle detected by this type of member is an angle in a coordinate system fixed to the ship on which the antenna is mounted, that is, the ship, the write address to the frame memory is:
It rotates in synchronization with the rotation of the antenna in the coordinate system fixed to its own ship and at the same angular velocity. For example, when the radiation direction of the antenna is directed to the own bow direction and an echo signal is obtained from that direction, the received echo signal is written to an address belonging to the own bow direction in the data on the frame memory. After that, when the radiation direction of the antenna turns to the direction of the ship's bow again, the echo signal received from the direction of the ship's own bow is written to the address belonging to the direction of the ship's bow in the data on the frame memory. It is. That is, the data on the frame memory is updated at the same speed as the speed at which the radiation direction of the antenna rotates. If the own ship is not turning, the new position and trend of each target existing around the own ship can be correctly known sequentially by such writing.

[0006]

However, when the ship is turning, the speed of change of the detection signal transmission direction on the earth surface and the change speed of the detected detection signal transmission direction (=
(The rotation speed of the write address on the frame memory) does not match.

[0007] For example, it is assumed that the radiation direction of the bow of the own ship and the aerial is pointing to the north at a certain time. Also,
Thereafter, it is assumed that the ship turns. Further, it is assumed that when the radiation direction of the aerial is again directed to the direction of the own bow, as a result of the turning of the own ship, the direction of the own bow has shifted from true north by an angle θ1. Since it is the angle in the coordinate system fixed to the own ship that is detected as the detection signal transmission direction and used for the generation of the write address, in this case, it is actually obtained from a direction shifted from true north by θ1. The echo signal is written at the address where the echo signal obtained from the true north direction was written last time.

[0008] As described above, in the conventional ship radar device, when the ship turns, the echo signal is written to an address related to a direction shifted from the detection signal transmission direction in the coordinate system fixed on the earth surface. Problem. In other words, there is a problem that the radiation direction of the antenna rotates more than one rotation on the earth's surface while the radiation direction of the antenna makes one rotation with respect to the own ship, or only rotates less than one rotation. Was. This is because the target that should be able to be detected cannot be detected depending on the turning angular velocity of the ship, the size of the detected target on the image changes according to the turning angular velocity of the ship, the detection signal is continuously detected in the same or almost the same direction. , Which results in obtaining an overlapped echo signal.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and has been made in consideration of the situation where the ship itself (more generally, the moving body on which the vehicle is mounted) is turning. An object of the present invention is to enable writing on a memory providing a two-dimensional storage space in accordance with a detection signal transmission direction in a coordinate system fixed on the earth surface.

[0010]

In order to achieve the above object, the present invention provides (1) a detection device mounted on a moving body, and (2) a detection signal while rotating its radiation direction. And (3) a memory for providing a two-dimensional storage space, and (4) a detection signal transmission in a coordinate system fixed to the moving body. Means for detecting the direction; and (5) specifying an address corresponding to the position where the reflected wave is obtained among the addresses on the memory based on the detected detection signal transmission direction, and converting the received signal related to the reflected wave into the above-mentioned signal. (6) means for obtaining information indicating or capable of deriving the turning angular velocity of the moving object;
(7) A circuit for controlling the increase / decrease of the rotational angular velocity in the radiation direction of the transmitting / receiving member in accordance with the turning angular velocity of the moving body so that the rotational angular velocity in the radiation direction of the transmitting / receiving member in the coordinate system fixed to the earth surface is constant. It is characterized by having.

As described above, in the present invention, the rotational angular velocity in the radiation direction of the transmitting / receiving member is controlled to increase or decrease according to the turning angular velocity of the moving body. This control is performed so that the rotational angular velocity in the radiation direction of the transmitting / receiving member in the coordinate system fixed on the earth surface is constant. In other words, the turning direction of the moving body according to the mounting is in the same direction as the rotational angular velocity of the radiation direction of the transmission / reception member, and therefore (without the control according to the feature of the present invention) the radiation of the transmission / reception member in the coordinate system fixed to the earth surface. If the rotational angular velocity in the direction becomes larger than that in the coordinate system fixed to the moving body, the rotational angular velocity of the transmitting / receiving member in the radiation direction is controlled to be reduced by an angular velocity corresponding to the turning angular velocity of the moving body. Conversely, the turning direction of the moving body according to the mounting is opposite to the rotational angular velocity in the radiation direction of the transmitting / receiving member, and therefore (without the control according to the features of the present invention) the transmitting / receiving member in the coordinate system fixed to the earth surface If the rotational angular velocity in the radiation direction of the moving body becomes smaller than that in the coordinate system fixed to the moving body, the rotational angular velocity in the radiation direction of the transmitting / receiving member is controlled to increase by an angular velocity corresponding to the turning angular velocity of the moving body. You.

On the other hand, also in the present invention, a write address to a memory is generated based on a detection signal transmission direction in a coordinate system fixed to a moving body. When the rotational angular velocity in the radiation direction of the transmitting / receiving member is controlled to be reduced by an angular velocity corresponding to the turning angular velocity of the moving body, the change speed of the detection signal transmission direction in the coordinate system fixed to the moving body is reduced by the angular velocity, It increases when the increase is controlled. Therefore, in the present invention, the rotation of the write address to the memory is generated on the earth surface, although the write address to the memory is generated based on the detection signal transmission direction in the coordinate system fixed to the moving object. Since the speed is synchronized with the detection signal transmission direction in the fixed coordinate system and becomes the same speed, it is possible to know more accurately from the data in the memory about the presence or absence and properties of the target (for example, to obtain a more accurate image based on the data in the memory). Display).

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of a marine radar apparatus according to an embodiment of the present invention. In order to transmit a detection signal from the marine radar device and receive a reflected wave from a target existing in the surroundings, the antenna 1 is installed at a location with a good view on the marine vessel to be mounted. The antenna 1 is, for example, a radiator having a predetermined directivity, a motor for rotating the radiator, a transceiver for wirelessly transmitting a detection signal using the radiator, and receiving a reflected wave by the radiator. It has components. The transmission and reception operation by the antenna 1 is performed by the CPU circuit 12.
Is controlled by the transmission / reception control circuit 11. Antenna 1
Is reflected by the A / D conversion circuit 2, and the resulting data is temporarily stored in the sweep memory 3 and further written on the radar video processing display memory 7. The sweep memory 3 sweeps data at least one time (= corresponding to one detection signal)
Is a buffer memory that holds data over a period of time. To perform the PPI display, for the data on the sweep memory 3 to be written to the radar video processing display memory 7, that is, for the write data in the figure, a write address corresponding to the two-dimensional position where the write data was obtained is generated. Then, the write address is designated and the write data is written to the radar video processing display memory 7. The write address is generated by the coordinate conversion circuit 6.

The radar image processing display memory 7 is a frame memory capable of storing radar data for one scan (corresponding to one rotation of the antenna), and provides a two-dimensional storage space corresponding to the screen of the CRT display 9. are doing. CRT display 9
In order to display the radar image on the screen of the PPI, the data, that is, the PPI display data is read out from the radar image processing display memory 7 in accordance with the display address specified by the CPU circuit 12, and is read by the D / A conversion circuit 8 into the analog image signal. And supplies it to the CRT display 9. The display address generated by the CPU circuit 12 is the CRT display 9
Is an address corresponding to the screen scan of the above. CRT display 9
For example, in order to display various graphics in addition to the radar image on the screen of the CPU, the graphic data is developed on the graphic frame memory 14 by the graphic control circuit 13 under the control of the CPU circuit 12, and the radar image processing display memory 7 is displayed. Is superimposed on the data read from the PPI display data and the data developed on the graphic frame memory 14, that is, the graphic display data.
It is supplied to the T display 9.

The processing for generating a write address is executed as follows. First, the antenna rotation signal generation circuit 4
Generates an antenna rotation signal, for example, a pulse signal, every time the radiating section of the antenna 1 rotates a predetermined angle with respect to the own ship, and supplies the signal to the angle signal control circuit 5. The gyro interface circuit 10 receives a signal indicating the course of the ship from a device such as a gyro (not shown) under the control of the CPU circuit 12 and supplies the signal to the angle signal control circuit 5. The angle signal control circuit 5 calculates the following equation based on the antenna rotation signal from the antenna rotation signal generation circuit 4, the own course from the gyro interface circuit 10, and the display mode and course reset course given from the CPU circuit 12.

## EQU1 ## HUP: .theta. = ANT NUP: .theta. = ANT + GYRO CUP: .theta. = ANT + GYRO-COURSE An angle signal .theta. Is generated. The angle signal θ is supplied to the coordinate conversion circuit 6, which calculates the following equation:

X = XC + R · sin θ Y = YC + R · cos θ The write address (X, Y) is generated.

The equation for generating the angle signal θ depends on which of the three modes, HUP / NUP / CUP, is used as the display mode. In HUP, the bow of own ship is always CR
A mode in which the radar image is displayed so as to face up on the screen of the T display 9, NUP is a mode in which the radar image is displayed so that the north always faces up on the screen of the CRT display 9, and CUP is an illustrated mode. In this mode, the radar image is displayed so that the own course, that is, the course at the time of course reset, when the reset switch is operated or the like is turned upward on the screen of the CRT display 9. In the formula, ANT is an angle derived from the antenna rotation signal, and indicates a direction of transmitting a detection signal of the antenna 1 with respect to the own ship, for example, its bow direction. GYRO is an angle derived from a signal obtained through the gyro interface circuit 10 and indicates a course of the ship based on a predetermined azimuth on the earth surface, for example, north. COURSE is the course at the time of course reset. The display mode can be classified into two modes, TM / RM, from another viewpoint. TM is a mode in which a radar image is displayed so that a fixed target is displayed at a fixed position on the screen of the CRT display 9.
M is a mode in which a radar image is displayed so that the own ship position is displayed at a fixed position on the screen of the CRT display 9. In the formula, (XC, YC) is a conversion start coordinate, and TM
In the case of, it moves with the movement of own ship. The movement of the own ship can be known from ship speed information or the like obtained from a device not shown. In the case of RM, the conversion start coordinates (XC, YC) are fixed to a specific address on the radar video processing display memory 7, for example, an address corresponding to the center of the radar video display window. R is the distance to the target, which can be known from the time from when the detection signal is transmitted from the radiating portion of the antenna 1 to when the reflected wave is received.

By using the write address (X, Y) generated in this way to write to the radar video processing display memory 7, the two-dimensional data provided by the radar video processing display memory 7 is provided. In the storage space, PPI display data indicating the presence or absence of a target around the own ship can be obtained. In addition, it is possible to control which direction is to be displayed on the screen and which one of the fixed target and the own ship is fixed on the screen by designating the display mode.

In this embodiment, an antenna rotation control circuit 15 is further provided. Antenna rotation control circuit 15
Under the control of the CPU circuit 12, and based on a signal supplied from the gyro via the gyro interface circuit 10 and an antenna rotation signal, the motor constituting the antenna 1 is controlled to increase or decrease the rotation speed of the radiation unit. Control.

Here, the angular velocity of the antenna that can be derived from the antenna rotation signal, that is, the speed of change of the detection signal transmission direction in the coordinate system fixed to the ship, is represented by ωa. Also, the turning angular velocity of the own ship that can be derived from the signal supplied through the gyro interface circuit 10 is represented by ωs. When the turning direction of the ship is the same as the rotation direction of the antenna 1 (FIG. 2B), the antenna rotation control circuit 1
In the case of the ship radar apparatus without 5 or the conventional ship radar apparatus, ωs = 0, that is, when the ship is not turning (FIG. 2).
Compared with (A)), the angular interval between sweeps is increased. For this reason, the address that would have been updated by writing when the ship was not turning may not be updated by writing. Therefore, in the present embodiment, the antenna rotation control circuit 15 is provided, and when the turning direction of the ship is the same as the rotation direction of the antenna 1, the antenna 1
Is reduced by ωs (FIG. 2C). At this time, an antenna rotation signal or a signal indicating a detection signal transmission direction in the own ship fixed coordinate system is input from the antenna rotation signal generation circuit 4, and the rotation angular velocity ω in the detection signal transmission direction in the coordinate system fixed on the earth surface is calculated. Control is performed so that the speed is the same as when the ship is not turning. If the turning direction of the ship is opposite to the direction of rotation of the antenna 1, the direction of the antenna 1 is reversed.
To increase the rotational angular velocity of the radiating section.

As described above, according to this embodiment, the write address to the radar video processing display memory 7 is generated based on the detection signal transmission direction in the coordinate system fixed to the moving body. The rotation of the write address to the radar image processing and display memory 7 is synchronized with the detection signal transmission direction in the coordinate system fixed on the earth surface and becomes the same speed. As a result, while the radiating portion of the antenna 1 makes one rotation, the data in the radar image processing and displaying memory 7 is updated just over the circumference 2π (rad) of the own ship. A situation in which data stored at an address where data should be updated is not updated, and a situation in which echo signals are obtained in duplicate in a plurality of adjacent sweeps (duplicate detection) is less likely to occur. That is, although the image of the target that is actually present is not displayed, the image of the target is displayed, but the number of echo signals (the number of hit sweeps) from the target is different from that when the ship does not turn. Therefore, phenomena such as inaccurate display are unlikely to occur, and it is possible to more accurately and reliably display the presence / absence, position, property, and the like of the target as compared with the related art. This effect is particularly evident in the water area where the ship on which the ship is mounted often makes a turn, or in an operation mode where the ship often makes a large turn.

In the above description, an example of a radar apparatus for a ship has been described. However, the detection device according to the present invention may be mounted on a moving object of another type, and the present invention may be applied to a detection device other than the radar device. It may be realized. The member for transmitting and receiving the detection signal is not limited to the antenna 1. This should be determined according to the type of the detection signal (radio wave, light, sound wave, etc.). When the antenna 1 is used, the configuration is not limited to the configuration described above. Further, correlation processing, movement trajectory generation processing, and the like may be performed using the radar video processing display memory 7, or another type of display device may be used instead of the raster scan type CRT display 9. .

[Brief description of the drawings]

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

FIG. 2 is a diagram showing the effect of antenna rotation control according to the own ship turning angular velocity in a coordinate system fixed to the earth surface, and in particular, FIG. 2A shows a detection signal transmission direction in a state where the own ship is not turning; (B) shows the detection signal transmission direction in the related art when the ship is turning in the same direction as the rotation direction of the antenna, and (C) shows the detection signal transmission direction in the above embodiment in the same state. , Respectively.

[Explanation of symbols]

1 antenna, 4 antenna rotation signal generation circuit, 5 angle signal control circuit, 6 coordinate conversion circuit, 7 radar video processing display memory, 9 CRT display, 10 gyro interface circuit, 12 CPU circuit, 15 antenna rotation control circuit.

Claims (1)

[Claims] 1. A detection device mounted on a moving body,
A transmitting / receiving member for transmitting a detection signal wirelessly while rotating its radiation direction and receiving a reflected wave from a surrounding target, a memory for providing a two-dimensional storage space, and a coordinate system fixed to the moving body. Means for detecting the detection signal transmission direction, and specifying the address corresponding to the position where the reflected wave was obtained among the addresses on the memory based on the detected detection signal transmission direction, and setting the received signal related to the reflected wave to the A detecting device comprising means for writing to a memory; means for obtaining information indicating or capable of deriving the turning angular velocity of the moving object; and wherein the rotational angular velocity in the radiation direction of the transmitting / receiving member in a coordinate system fixed to the earth surface is constant. And a circuit for controlling the increase / decrease of the rotational angular velocity in the radiation direction of the transmitting / receiving member according to the turning angular velocity of the moving body.