JPH04238285A - Radar device - Google Patents

Abstract

PURPOSE:To obtain a single image data from radar images obtained from multiple radars, and display and detect a target. CONSTITUTION:Radar transmit-receive circuits 3, 4 use radar antennas 1, 2 respectively to transmit and receive the pulse electric wave. A/D converter circuits 5, 6 convert the received signal to the digital data respectively, and R memories 7, 8 store the data by one sweep respectively. A control circuit 9 switches a switch circuit 10 in response to the direction of the radar antennas 1, 2 to write the content of the Rtheta memories 7, 8 to an XY memory 12. Single image data is thereby obtained from two radar images.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radar apparatus that detects a target using a plurality of radars.

0002

2. Description of the Related Art Conventionally, in systems equipped with two radar devices, each radar has been used in a form depending on its purpose. For example, an interswitch is used to determine which radar antenna and transmitting/receiving section of a radar device is used and which indicating section is used for detection.

0003

[Problems to be Solved by the Invention] However, in conventional radar devices, even when using multiple radars, image display is performed using only a single radar antenna and transmitting/receiving section; It was not possible to simultaneously display and detect radar video signals from the radar antenna and transmitter/receiver.

An object of the present invention is to provide a radar device that can display radar images and detect targets using radar image signals obtained from a plurality of radars substantially simultaneously.

[0005]

[Means for Solving the Problems] A radar device according to claim 1 of the present invention includes means for converting video signals obtained from a plurality of radars into digital image data, and dividing the image data into sections at approximately equal intervals. an image memory that is allocated to each image and stored as a single image; means for determining a write address to the image memory from antenna azimuth signals and transmission/reception timing signals obtained from a plurality of radars; and means for writing image data into the divided sections.

[0006] A radar device according to a second aspect of the present invention includes: an image memory that stores digital image data of radar images obtained from a plurality of radars; and an image data readout control means that reads data at the same address from the plurality of image memories. and image data synthesizing means for calculating an added value or an average value of each read data.

Furthermore, the radar apparatus according to claim 3 has an image memory that stores digital image data of radar images obtained from a plurality of radars, and reads images from each image memory at an address different from the readout address of the other image memories. The image forming apparatus is characterized in that it comprises a means for reading out data, and an image for one screen is constructed from the image data read out from each image memory.

[0008]

[Operation] In the radar device according to claim 1, video signals obtained from a plurality of radars are each converted into digital image data, and these image data are allocated to sections at approximately equal intervals to form a single image. stored in memory. At that time, the write address to the image memory is determined from the antenna azimuth signals and transmission/reception timing signals obtained from multiple radars, and the image data is stored at the determined address and within the section of the memory allocated to each radar. is written.

For example, when writing one sweep of images obtained each time the radar antenna rotates by a certain angle into the image memory, when allocating the images obtained from each radar at each fixed angle, the images are synthesized as shown in FIG. image data can be obtained. Furthermore, for example, when images obtained from two radars are allocated to areas partitioned at equal intervals on the XY coordinates, a single image is formed by combining the two radar images as shown in FIG. 5.

In the radar device according to the second aspect, digital image data of radar images obtained from a plurality of radars are stored separately in the image memory, and data at the same address is read from the plurality of image memories by the image data reading control means. Read out. Then, the image data synthesizing means calculates the sum or average value of the data read from each image memory as synthesized image data. Since images of reflected waves from the same point are written to the same address in the image memory, the composite image is obtained as an image in which the radar images detected by each radar are superimposed.

In the radar apparatus according to the third aspect of the present invention, digital image data of radar images obtained from a plurality of radars are stored separately in each image memory. The image data in each of these image memories is read out at an address different from the readout address of the other image memories, and the image data read out from each image memory constitutes one screen's worth of images.

For example, when the radar detection range is divided finely in the X-axis and Y-axis directions in the If the digital image data of the radar image that has been combined is shown in (A) and (B) in FIG. 10, the image data after the synthesis is shown in (
C).

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a block diagram of a radar apparatus according to a first embodiment of the present invention. In FIG. 1, 1 and 2 are radar antennas, respectively. Radar transmitting/receiving circuits 3 and 4 transmit and receive pulsed radio waves via radar antennas 1 and 2, respectively. The control circuit 9 provides a transmission trigger pulse to the radar transmitting/receiving circuits 3 and 4, and counts a distance counter (not shown) to obtain distance data R. Further, the directions of the radar antennas 1 and 2 are detected, and the switching circuit 10 is switched according to the direction of each antenna.

[0014] A/D conversion circuits 5 and 6 convert received signals outputted from radar transmitting and receiving circuits 3 and 4, respectively, into digital data. The Rθ memories 7 and 8 store the converted digital data for one sweep. The switching circuit 10 selects the Rθ memory 7 or 8 according to the switching signal from the control circuit 9.
Selectively read data from either one. The coordinate conversion circuit 11 converts polar coordinates based on distance data R and antenna orientation data θ given from the control circuit 9 into XY coordinate data. The XY memory 12 stores coordinate-converted X,
Using the Y data as an address, Rθ is sent via the switching circuit 10.
Stores data read from memory 7 or 8. The display unit 13 displays the XY memory 1 according to the scanning of the CRT, for example.
The contents of 2 are read out, a display signal is created, and the radar image is displayed.

The control circuit 9 shown in FIG. 1 detects the directions of the two radar antennas 1 and 2, and also controls the switching circuit 10 so that the Rθ memory 7 is selected when the radar antenna 1 is in a predetermined direction. When the direction of the radar antenna 2 is the predetermined direction, the Rθ memory 8
The switching circuit 10 is switched so that . For example, when switching one 360-degree scan every sweep, radar images from two radars are combined as shown in FIG. In the same figure, for example, the solid line is radar antenna 1.
The dashed line is a radar image using radar antenna 2.

In the embodiment shown in FIG. 1, since the control circuit 9 detects each direction of the radar antennas 1 and 2, the radar antennas 1 and 2 can be scanned asynchronously. In addition, radar antennas 1 and 2
Regardless of the direction of the radar antennas 1 and 2, the Rθ memories 7 and 8
The contents of XY memory 1 are read out alternately at fixed time intervals.
It is also possible to write to 2.

Furthermore, in the embodiment shown in FIG. 1, an Rθ memory is provided for each radar transmitting/receiving circuit, but if the direction of each radar antenna and the radio wave emission timing are synchronized, one Rθ memory can be used.
It is also possible to use memory for this purpose.

Furthermore, in the example shown in FIGS. 1 and 2, video signals from two radars are used over the entire range in the distance direction, but as shown in FIG. The other radar for long-distance detection is used for short-distance detection, and by combining the two radar images, it is possible to efficiently utilize the two radars in the distance direction.

In the radar device according to this embodiment, if the number of XY memories is increased to a certain extent (for example, 800 x 800 pixels or more), even if image data is alternately stored in the image memory, 2
It is possible to memorize two radar images without sacrificing their resolution. Furthermore, since the stored contents of the image data of each radar image can be updated in synchronization with the rotation of each radar antenna, unstable targets such as small targets can be displayed without affecting the other radar.

Next, a block diagram of a radar device according to a second embodiment is shown in FIG. The difference from the configuration of the radar device shown in FIG. 1 is that a write selection circuit 14 is provided. This write selection circuit 14 is used when finally writing the image data of the radar image obtained using the radar antenna 1 and the image data of the radar image obtained using the radar antenna 2 to the XY memory 12. This is for selecting the writing area. That is, whether or not data can be written to the XY memory 12 is controlled depending on which of the Rθ memories 7 and 8 is selected by the switching circuit 10 and the write address of the XY memory. If the image data of the two radar images are allocated alternately at equal intervals in the XY coordinates, a single radar image is created in which the two radar images are partially replaced with other radar images, as shown in Figure 5. is obtained. Here, for example, the black portions are pixels of the image obtained by the radar antenna 1, and the white portions are the pixels of the image obtained by the radar antenna 2.

The combination of two radar images is not limited to the pattern shown in FIG. 5; for example, a linear area may be allocated as shown in FIG. 6, and when three radar images are combined, the pattern shown in FIG. As shown, the pixels of each radar image may be arranged regularly. In FIG. 7, A, B, and C correspond to pixels of three types of radar images.

The radar device according to the second embodiment can uniformly superimpose two radar images regardless of the area in the image memory, and each allocated area in the image memory has a corresponding radar image. This has the effect that the superimposition operation is performed reliably because only the data is written.

Next, a block diagram of a radar apparatus according to a third embodiment is shown in FIG. In FIG. 8, 1 and 2 are radar antennas, respectively. Radar transmitting/receiving circuits 3 and 4 transmit and receive pulsed radio waves using radar antennas 1 and 2, respectively. Radar control circuits 19 and 20 provide trigger pulses to radar transmitting and receiving circuits 3 and 4, respectively, and count up distance counters (not shown) to obtain distance data. The radar antennas 1 and 2 are also controlled to rotate, and their orientations are detected to obtain orientation data. Data control circuits 15 and 16 convert the received signals outputted from radar transmitting and receiving circuits 3 and 4, respectively, into digital data, convert it into an XY coordinate system, and write it into image memories 17 and 18, respectively. Read control circuit 21
reads the contents of the image memories 17 and 18 simultaneously. The address control circuit 22 sequentially increments the read addresses of the image memories 17 and 18 from the start address to the end address, and repeats the control. The adding circuit 23 adds the values of image data output simultaneously from the image memories 17 and 18. The 1/2 division circuit 24 divides 1/2 of the addition result.
Calculate the value of The display unit 25 converts the obtained image data string into a video signal and displays it on, for example, a CRT.

[0024] In the above manner, an averaged image of two radar images is obtained.

Two image memories 17 and 18 shown in FIG.
The signals include an unnecessary signal (a) such as noise with a small spread, a target signal (b) received by one radar, and a target signal (c) received simultaneously by two radars. By adding the image data of these two image memories 17 and 18, the signal density of (a) increases and the signal level of (c) increases. Then, by halving the added value, the signal level of (a) is halved and high density, and (b)
The signal level of (c) becomes 1/2 the original level, and the signal of (c) becomes the original level. Therefore, the signal (b) can be left in one image data without displaying the unnecessary signal (a) strongly or weakening the signal (c).

Next, a block diagram of a radar device according to a fourth embodiment is shown in FIG. The difference from the radar device shown in FIG. 8 is that there is no addition circuit 23 and 1/2 division circuit 24 for calculating an average value, and the operations of the read control circuit 21 and address control circuit 22. In FIG. 9, read control circuit 2
1 performs control to read out the contents of the image memories 17 and 18 alternately. The address control circuit 22 is the image memory 17, 18
Addresses are given in order from the start address to the end address, but the same address is not given to the image memory 17 and the image memory 18, but is given alternately. As a result, image data is read out from the image memories 17 and 18 alternately and in sequence.

For example, if the stored contents of the image memories 17 and 18 are as shown in FIGS. 10(A) and 10(B),
A single composite image will be displayed as shown in C). However, in FIG. 10, 1, 2, 3, . . . and a, b, c, . . . are all one pixel.

According to this fourth embodiment, the image memory 1
Image data of a target that appears only on either one of 7 and 18 has 1/2 the number of pixels, but it can be displayed uniformly by making the pixels finer than the spot size of the CRT.

[0029] If the image data of the two radar images are extracted pixel by pixel alternately and combined into a single image data in this way, the effect of averaging the two radar images can be obtained, but the screen is divided relatively roughly. Alternatively, two radar images may be assigned.

[0030]

[Effects of the Invention] According to the present invention, the following effects can be achieved.

[0031] By determining the status of multiple radars according to the purpose of target object detection, for example, unstable targets that can be received by one radar but cannot be received by other radars can be combined on a single screen. This makes target detection easier. In the radar device according to the first aspect, image data of a plurality of radar images can be synthesized using a small amount of image memory, which is substantially the same as in the case of a single radar device. In addition, in the radar device of claim 2, the target object that appears only in some radar images among the plurality of radars can be detected without strongly displaying unnecessary signals such as noise and without reducing the signal level of the target object. The signal can also be obtained as single image data. Therefore, even unstable targets and weak target signals can be easily detected. Furthermore, in the radar apparatus of the third aspect, a composite image of a plurality of radar images can be obtained without increasing the level and density of unnecessary signals such as noise.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a radar device according to a first embodiment.

FIG. 2 is a diagram showing an example of image memory allocation in the radar device according to the first embodiment.

FIG. 3 is a diagram showing another example of allocation of image memory in the radar device according to the first embodiment.

FIG. 4 is a block diagram of a radar device according to a second embodiment.

FIG. 5 is a diagram showing an example of allocation of image memory in a radar device according to a second embodiment.

FIG. 6 is a diagram showing another example of allocation of image memory in the radar device according to the second embodiment.

FIG. 7 is a diagram showing another example of allocation of image memory in the radar device according to the second embodiment.

FIG. 8 is a block diagram of a radar device according to a third embodiment.

FIG. 9 is a block diagram of a radar device according to a fourth embodiment.

FIG. 10 is a diagram showing an example of reading out the image memory of the radar device according to the fourth embodiment, in which (A) and (B) are the contents of two image memories, and (C) is one configured screen. The images are shown respectively.

Claims (3)

[Claims] 1. Means for converting video signals obtained from a plurality of radars into digital image data, an image memory for allocating the image data to sections at approximately equal intervals and storing them as a single image; A radar comprising means for determining a writing address to the image memory from an antenna azimuth signal and a transmission/reception timing signal obtained from the radar, and means for writing image data at the determined address and within the allocated section. Device. 2. An image memory for storing digital image data of radar images obtained from a plurality of radars, an image data readout control means for reading out data at the same address from the plurality of image memories, and an image data readout control means for reading out data at the same address from the plurality of image memories; A radar device comprising image data synthesis means for calculating an added value or an average value. 3. An image memory for storing digital image data of radar images obtained from a plurality of radars, and means for reading image data from each image memory at an address different from read addresses of other image memories, A radar device characterized in that an image for one screen is constructed from image data read from each image memory.