JPS6022307B2 - radar device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is used in a three-dimensional radar device using a pencil beam, etc., to shorten the time required to search a predetermined coverage area in a predetermined order, and improve the data rate. The present invention relates to a radar device.

Generally, a phased array antenna is used to
2. Description of the Related Art A three-dimensional radar system that searches a predetermined airspace within a predetermined azimuth and elevation angle range by electronic scanning alone or in combination with mechanical scanning is well known. Note that FIGS. 1 and 2 show different methods in which the elevation angle range (2) is scanned in a raster manner by a pencil beam. As shown in FIGS. 1 and 2, a three-dimensional radar system normally searches a predetermined airspace at a fixed altitude and a fixed elevation angle. In this case, in order to shorten the time required to scan the elevation range (2) (referred to as frame time T), the radar pulse repetition time is often shortened as the elevation angle becomes higher. On the other hand, search radars such as three-dimensional radars often require MT1 (moving target detection) processing.

MTI processing in a three-dimensional radar device using pencil beam scanning is performed by stagger processing using a plurality of pulse trains or more for only the necessary low-elevation angle beam. That is, in Fig. 3, #1 to #7 respectively indicate pencil beams, and among these, #1 and #2
It is assumed that a pencil beam of 1 is required to be subjected to MTI processing. Here, an example of the timing relationship of transmission and reception by pencil beams #1 to #7 is shown in FIG. Note that for beams #1 and #2 that require MTI processing, for example, four (symbols a to d) pulse trains for stagger processing are shown.
Also, in Fig. 4, as mentioned above, the radar pulse repetition time becomes shorter as the elevation angle becomes higher, that is, as the pencil beam changes from #1 to #7.
It has become. By the way, the longer the maximum detection distance of low elevation angle pencil beams #1 and #2 that require MTI processing,
The time required for MTI processing becomes long, the frame time required to scan the elevation angle range (2) becomes long, and the data rate deteriorates.

However, in long-distance three-dimensional radar equipment, M
There is no practical need to perform TI processing over the entire range of the maximum detection range of the low-elevation pencil beam; for example, the maximum detection range of 2
In the case of 00NM (nautical miles) or more, the required detection distance for MTI processing is often about 80 to 10 km.

In addition, in terms of clutter suppression performance for MTI-processed bag counterfeits, MT
It is well known that it is advantageous to shorten the radar pulse repetition time by shortening the distance range in which I processing is performed. Focusing on this point, it is already possible to provide beams dedicated to MTI processing, ie, MTI beams #8 and #9, as shown in Figure 5, which have a maximum detection distance B of about 80 to 10 degrees M in the low elevation angle range. Are known.

In this case, in order to search for areas A beyond the maximum detection distance range of the MTI beam in which MTI processing is not performed within the low elevation angle range, it is necessary to perform beam scanning at approximately the same elevation angle with pencil beams #1 and #2 separately from the MTI beam. Yes, like this M
FIG. 6 shows the timing of radar transmission and reception when using the TI beam. In this way, the maximum detection distance is relatively short M
In the case of the system with TI beams, as is clear from Figure 6, in the radar reception section by pencil beams #1 and #2, the distance section where searching has already been carried out by MTI beams #8 and #9 is also affected. It will be received again.
This has the disadvantage of increasing the frame time required to scan a given elevation angle range (2). The present invention has been made in order to eliminate the above-mentioned drawbacks.The present invention has been made in order to eliminate the above-mentioned drawbacks. The present invention provides a radar device that can shorten frame time by performing detection.

An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 7, reference numeral 71 is a radar antenna using an electronic scanning array antenna, and the beam is scanned in the height direction by an electronic scanning controller 72, and in the azimuth direction, the beam is scanned, for example, mechanically. A beam scan similar to that shown in Figure 5 was performed.

However, in the present invention, the transmission/reception timing corresponding to the beam scanning in FIG. 5 is different from the subordinate transmission/reception timing corresponding to the beam scanning in FIG. 5, and this point will be described later. Further, 73 is a circulator, 74 is a coder transmitter, 75 is a coder receiver, and 76 is a timing controller. In the radar device with the above configuration, beam scanning (MT as in Fig. 5)
I-beams #8 and #9 are used.

) is shown in FIG. 8.
That is, during each transmission/reception period of the low-elevation pencil beams #1 and #2, the high-elevation pencil beam #6 has a shorter search range than the maximum detection range B of the MTI beams #8 and #9.
The timing controller 76 controls the transmission and reception according to #7. Here, the electronic scanning controller 7
FIG. 9 shows an example of the timing of beam scanning calculation in a radar apparatus having a phased array antenna using a latching ferrite mover for beam angle variable setting in No. 2.

That is, when the pencil beam #6 with a high elevation angle is shot on the forehead immediately after the pencil beam #1 with a low elevation angle hits the fin, and after receiving the reflected wave of this beam #6, the reflected wave of the beam #1 is received. Before the neck shot of beam #1, set the latching phase shifter to the phase shift amount for beam #1 transmission, and after beam #1 shot and before beam #6 fin shot, set the latching phase shifter to the phase shift amount for beam #6 transmission. Set to phase shift amount.

Then, after beam #6 has been shot, the latching phase shifter is set to the phase shift amount for beam #6 reflected wave reception, and after the beam #6 reflected wave reception period has ended, the latching phase shifter is set to the phase shift amount for beam #1 reflected wave reception. do. Then, before setting the transmission phase shift amount of beam #1 and beam #6, the set phase shift amount is calculated for each,
Timing control is performed so that each calculation result data is transmitted before each phase shift amount is set. Next, regarding the pencil beams #1 and #7, the pencil beams #1 and #7 mentioned above are
Similar to the timing relationship in #6, fin shooting, reception section allocation,
Phase shift amount calculation, calculation result transmission, and phase shift amount setting are performed.
The receiving sections of pencil beams #6 and #7 are set to be the same as or slightly shorter than the receiving sections of dedicated beams #8 and #9 reflected waves during Korean firing. .

The above explanation is for the case using a latching phase shifter, but
Timing control when using a PIN diode phase shifter is performed as shown in FIG.

In other words, beams #1 and #6 are fired continuously, and beam #1
During the Korean firing period, the phase shift amount setting for beam #1 is performed, and the switching from the phase shift amount setting for beam #1 to the phase shift amount setting for beam #6 is controlled by the calculation result data for beam #6. , the phase shift amount setting for beam #6 is performed over the beam emission period of beam #6 and the beam #6 reflected wave reception period, and the phase shift amount setting for beam #6 is changed from the phase shift amount setting for beam #6 to the phase shift amount setting for beam #1 based on the calculation result data for beam #1. Switching to phase shift amount setting is controlled,
Beam #1 reflected wave reception is performed by setting the phase shift amount for beam #1 by this switching. and beam #2, #
7 is also controlled in the same manner as the timing relationship of beams #1 and #6 described above. According to the radar device described above, beam #6 with a high elevation angle is detected by using the reception section where the MTI beams #8 and #9 are separately searched among the sections in which reflected waves by pencil beams #1 and #2 can be received. , #7
beam #6 and reflected waves are received, compared to the conventional transmission/reception timing settings shown in Figure 6.
, #7, the frame time can be shortened by the transmission/reception period AT.

In the above description of the embodiment, the number of beams scanning the predetermined elevation angle range (2) and the number of MTI beams are limited, but it goes without saying that the present invention can be applied to the case where any number of beams are employed.

In addition, although the explanation of the embodiment described above uses a phase shifter to scan a pencil beam, the present invention is also effective when scanning in the elevation direction is frequency scanning or frequency-phase composite scanning. Of course, it can be applied to.

Further, the present invention is not limited to a radar device that uses an MTI beam, and the essential point is to provide means for transmitting a first transmission pulse signal to a first low elevation angle region at a first time interval, and a means for transmitting a first transmission pulse signal to a first low elevation angle region at a first time interval. a second transmitted pulse signal into a second low elevation region at least partially overlapping with the first low elevation region at a second time interval greater than the first time interval; It can be applied to a radar device equipped with a means for transmitting.

Brief explanation of the drawings Figures 1 and 2 are diagrams showing different methods of beam scanning in a three-dimensional radar device, and Figure 3 is a low elevation beam that requires MTI processing in the beam scanning method of Figure 1. FIG. 4 is a diagram showing an example of transmission and reception timing corresponding to the beam scanning of FIG. 3, FIG. 5 is a diagram showing an example of a beam of a conventional radar device, and FIG. is a diagram showing an example of transmission/reception timing corresponding to the beam scanning of FIG. 5, FIG. 7 is a configuration explanatory diagram showing an embodiment of the radar device according to the present invention, and FIG. 8 is a diagram corresponding to beam scanning by the device of the present invention. FIG. 9 is a diagram showing an example of the transmission/reception timing when a latching ferrite phase shifter is used in the radar device according to the present invention, and FIG. 1
FIG. 0 is a diagram shown to explain the relationship between transmission/reception timing and phase shifter control timing when a P-melon diode phase shifter is used in the radar device according to the present invention.

71... Radar antenna, 72... Electronic scanning controller, 74... Radar transmitter, 76...
- Radar receiver, 76...timing controller.

Figure 1 Figure 2 Figure 3 Figure 5 Figure 7 Figure 4 Figure 6 Figure 8 Figure 9 Figure 10

Claims (1)

[Claims] 1 means for transmitting a first transmission pulse signal to a first low elevation angle region at a first time interval; means for receiving a first reflected wave by the first transmission pulse signal; means for transmitting a second transmit pulse signal to a second low elevation region at least partially overlapping with the first low elevation region at a second time interval greater than the second time interval; means for transmitting a third transmission pulse signal to an elevation angle region higher than the second low elevation angle region adjacent to or consecutively with the second transmission pulse signal; and a second reflected wave caused by the second transmission pulse signal. dividing the receivable period into a first period within a period corresponding to the reception period of the first reflected wave and a second period within a period excluding this first period; and means for receiving a third reflected wave caused by the third transmitted pulse signal and receiving the second reflected wave during the second period.