JP2001264412A - Radar having polarization plane control function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radar using the V polarized wave and the H polarized wave which effectively uses both received polarized waves, and finely selects the polarized waves to the change of the external environment. SOLUTION: A setting unit 14 sets the area based on the information on the range of the azimuth angle and the distance inputted by an operator, and one of the received vertical and horizontal polarized wave signals is set for the area based on the input of the operator. An indication switch 12 switches the information on the vertical and horizontal polarized wave reception according to the area and the received signal set in the area, and displays it on an indicator 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a normal environment, a clutter environment, that is, an environment in which reflection from the ground or reflection of clouds and rain due to terrain, and other disturbances (ECs).
M) A radar device that detects and tracks a target in an environment.

[0002]

2. Description of the Related Art Conventionally, a radar apparatus capable of extracting orthogonal polarization components can only process V (vertical) polarization or H (horizontal) polarization.

It is well known that in a noise environment such as clutter, the characteristics are different depending on each polarization. For example, with respect to ground clutter (reflection from the ground caused by the terrain), the H-polarized wave is less affected by clutter because the clutter reception intensity is smaller. Similarly, circular polarization is less affected by weather clutter (reflection of clouds and rain), and V polarization is less affected by multipath. The multipath indicates a reflected wave that reflects a target object and further reflects another object such as the sea surface to reach a radar.
When this multipath exists, one target is observed in a plurality. Further, depending on the shape of the target, the received signal strength may be higher in oblique polarization than in V polarization or H polarization.

The external environment such as the target environment and the clutter environment
Since it is changing every moment, the selection of the polarization needs to be finely changed according to the change. In a normal radar device, the direction of polarization is fixed, so that it has advantages and disadvantages in the above environment. At the time of weather clutter, there is a possibility that a target cannot be detected due to strong clutter intensity with linear polarization such as V polarization or H polarization.

In order to solve such a problem, there is a radar device which switches the polarization depending on the clutter environment or the like. Conventionally, however, switching of the entire screen or switching by designating a certain angle range is performed. I just went.

[0006]

In such a system,
In an environment in which the short distance is greatly affected by ground clutter and the long distance is greatly affected by multipaths in the same direction, it has not been possible to take measures to reduce both effects.

As described above, the present invention provides V-polarization and H-polarization.
It is an object of the present invention to provide a radar apparatus using polarized waves, which effectively uses both polarized waves and selects a polarized wave finely in response to changes in the external environment.

[0008]

According to the present invention, in order to solve the above problem, both V / H polarizations are transmitted at the time of transmission, and V / H polarizations are separately received at the time of reception. In addition to the polarization processing system and H polarization processing system, circular and polarized waves are generated by performing weighted addition of amplitude and phase on the received signal of V / H polarization, and the operator selects while viewing the display of each polarization. Control.

That is, a radar apparatus according to the present invention receives a vertical polarization and outputs a vertical polarization reception signal, and a horizontal polarization receiving means that receives a horizontal polarization and outputs a horizontal polarization reception signal. Wave receiving means, area setting means for setting an area based on the input azimuth and distance, and signal setting for setting one of the vertical and horizontal polarization reception signals for the area set by the area setting means And display means for switching and displaying information received by the vertical and horizontal receiving means in accordance with each area set by the area setting means and the received signal set by the signal setting means.

According to the present invention, the reception information display of the V polarization and the H polarization can be set separately for an arbitrary area defined by the azimuth and the distance, and the received V and H polarizations are used effectively. be able to.

Also, depending on the shape of the target, V polarization or H
An oblique polarization having a received signal strength larger than the polarization can be used for the above-mentioned arbitrary area, and the detection capability is improved.

Further, a circularly polarized wave can be selected in the above-mentioned arbitrary area where the weather clutter is generated, and the clutter suppressing ability is enhanced.

[0013]

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

FIG. 1 is a block diagram showing a configuration of a radar apparatus according to a first embodiment of the present invention. The V and H polarization transmission signals output from the transmitter 5 are output from the circulators 3 and 4
Are supplied to the vertical antenna element 1 and the horizontal antenna element 2 via the. The circulators 3 and 4 have a transmission / reception switching function. The length of the antenna elements 1 and 2 corresponds to the wavelength,
The supplied transmission signal resonates in the antenna element, and vertically and horizontally polarized waves are radiated.

The reflected signals from the target and the like are similarly received by the receivers 6 and 7 via the circulators 3 and 4. The received signals are frequency-converted by the receivers 6 and 7, and then converted into digital signals, and the signal processors 8, 9,
11 is input. In this embodiment, V polarization or H
In addition to polarization, V-polarization and H-polarization signals are subjected to amplitude and phase weighting operations by both polarization weighting combiners 10 to generate circularly polarized reception signals. The synthesizer 10 has V
The phase difference between the polarized wave and the H polarized wave received signal is adjusted to exactly 90 degrees, the amplitude is adjusted to the same, and both polarized waves are combined.

Each of the polarized signals subjected to the signal processing is selected by the video switch 12 in accordance with the area set by the setting section 14, and the reception result is displayed on the display 13. The display 13 performs color display or classification of line segments in order to make the information of each polarization easy to understand.

FIG. 2 is a diagram for explaining the characteristics of each polarization in the area. For example, for ground clutter from the ground, H-polarized light generally has a lower clutter reception intensity than V or circularly-polarized light. That is, there is little noise. Therefore, in such an area, it is preferable to display the H polarization reception information on the display. Also, V polarization is less affected by multipath from the sea surface, and similarly, circular polarization is less affected by weather clutter caused by clouds or rain. Therefore, it is preferable to display the V-polarized wave reception result in an area where multipath exists, and to display the circularly-polarized wave reception result in an area where weather clutter exists. Thus, it is necessary to set the reception polarization according to each area.

FIG. 3 shows the setting process and the video switch 12
6 is a flowchart showing the operation of the first embodiment.

The operator observes the screen of the display 13 (step S1) and sets which polarization reception information is to be displayed for each area (step S2). FIG. 4 shows a display example of the display screen. For example, in area a, received information affected by ground clutter is displayed. In such an area, the V polarization is strongly affected by clutter, as shown by the waveform on the left, while the H polarization is not significantly affected. Therefore, the operator sets the display of the reception information in the area a to H polarization. Similarly, a multipath has occurred in area b. That is, one target is displayed in a plurality. Since the V polarization is not so affected by multipath, the V polarization is set in such an area. In the area c, a circularly polarized wave is set because weather clutter is generated.

The way of setting is defined by the azimuth and distance range by directly inputting the range of azimuth and distance as numerical values in the setting unit 14 or by designating three points with a pointer provided on the display screen. An area including these three points in a fan-shaped outline may be set as the designated area.

The area thus set is defined by an azimuth angle, a distance, or an elevation angle or an altitude as described later. For example, when the operator sets the area b on the screen to V polarization using the setting unit 14, the setting unit 14 stores the azimuth angle range of this specific area, the distance range from the observation point, and the set polarization. .

When displaying the received information on the display 13, the video switch 12 first calculates the azimuth and distance on the screen of the pixel to be displayed, as in step S3. Next, the video switch 12 selects the input polarization signal set for the display pixel based on the area and polarization information set and stored in step S2, and displays a reception result based on the selected polarization ( Steps S4 to S6). For example, when the V polarization is set for the display pixel, the video switch 12 selects and displays the V polarization reception information Rv.
If "N" in step S6 (if it is neither V-polarization nor H-polarization), the reception result by circular polarization is displayed as in step S8. In this way, the video switch 12 determines the set polarization for all the pixels on the display screen, and displays the reception result on the display 13.

FIG. 5 is a block diagram showing a configuration of a radar apparatus according to a second embodiment of the present invention. This radar device has a plurality of video switches 12a to 12n and displays 13a to 13a.
13n, 14a to 14n. According to this configuration, a plurality of operators can simultaneously observe different areas by using the display 13 and the setting unit 14 with one transmission / reception circuit (1 to 11).

FIG. 6 is a block diagram showing a configuration of a radar apparatus according to a third embodiment of the present invention. This radar device has a configuration in which a combiner 10b and a V / H polarization combined signal processing unit 15 are added to the device shown in FIG. The shape of the target (generally an aircraft) may vary and may be V-polarization alone or H-polarization.
It may be easier to capture using oblique polarization, which combines V polarization and H polarization in a vector manner, than capturing only polarization.

FIG. 7 is a screen display example of the display 13 for explaining the setting of the oblique polarization. Wake d that seems to be the target
Is set by the setting unit 15, the polarization angle is changed on a separate screen as shown in the lower diagram of FIG. 7, and the polarization angle with the highest reception intensity is set for the wake. This polarization angle changing process is performed by the combiner 10b. That is, the synthesizer 10
b varies the intensity of the vertical and horizontal polarization vectors (0
〜1 times) Both polarizations are combined. The angle between the resultant combined vector and the vertical or horizontal polarization vector is the polarization angle. In this way, each polarization process is set for each wake.

FIG. 8 is a diagram showing a configuration of a radar apparatus according to a fourth embodiment of the present invention. This device is a phased array radar device using a plurality of antenna elements. The transmission signal output from the transmitter 5 is supplied to V-polarization and polarization combiners 16 and 17 via circulators 3 and 4 and further to a plurality of antenna elements 1 and 2 via an amplitude / phase controller 15. Supplied to Multiple amplitude / phase controllers 1
5 sequentially gives a phase difference to a plurality of signals supplied from the polarization combiner 16, for example. Therefore, the transmission signal is supplied to the plurality of V-polarized antenna elements 1 arranged side by side with the phases shifted by a predetermined delay time. Therefore, the radio waves radiated from the phased array radar are directed in a direction in which the radio waves radiated from the respective antenna elements have the same phase. By controlling the phase difference given to the transmission signals supplied to the plurality of antenna elements by the amplitude / phase controller 15, the radiation direction of the radio wave can be set arbitrarily and the radio wave can be scanned in all directions. .

Generally, the received information displayed on the display unit 13 is information obtained by adding signals received by scanning radio waves in the horizontal and vertical directions. The setting of the area according to the present invention is performed not only in the above-described planar setting but also in the vertical direction. FIG. 9 is a view for explaining this vertical setting process. The operator can specify the altitudes (elevation angles) h1 and h2 for the area c as shown in the left diagram, for example, and set the polarization for this area. The video switch 12 switches the polarization set to the three-dimensionally set area and displays the received information on the display 13.

Although the present embodiment has been described as applied to a phased array radar device, it goes without saying that the same applies to a reflector radar device or a digital beam type radar device.

[0029]

As described above, according to the present invention, in a radar apparatus using V-polarization and H-polarization, both polarizations are effectively used, and the polarization is finely adjusted with respect to changes in the external environment. A radar device for selecting a wave can be provided.

[Brief description of the drawings]

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

FIG. 2 is a diagram for explaining the characteristics of each polarization in each area.

FIG. 3 is a flowchart illustrating an area and polarization setting process and an operation of a video switch.

FIG. 4 shows a display example of a display screen.

FIG. 5 is a block diagram showing a configuration of a radar device according to a second embodiment of the present invention.

FIG. 6 is a block diagram showing a configuration of a radar device according to a third embodiment of the present invention.

FIG. 7 is a screen display example of a display for explaining setting of oblique polarization.

FIG. 8 is a diagram showing a configuration of a radar device according to a fourth embodiment of the present invention.

FIG. 9 is a view for explaining vertical setting processing.

Claims (4)

[Claims] 1. A vertically polarized wave receiving means for receiving a vertically polarized wave and outputting a vertically polarized wave receiving signal, a horizontal polarized wave receiving means for receiving a horizontally polarized wave and outputting a horizontally polarized wave receiving signal, Area setting means for setting an area based on the range information of the azimuth and distance to be set; and signal setting means for setting one of the vertical and horizontal polarization reception signals for the area set by the area setting means. And display means for switching and displaying information received by the vertical and horizontal receiving means in accordance with each area set by the area setting means and the received signal set by the signal setting means. Radar equipment. 2. The vertical and horizontal polarization receiving signals are synthesized,
The apparatus further comprises a circularly polarized wave generating means for generating a circularly polarized wave signal, wherein the signal setting means converts one of the vertical and horizontal polarized wave receiving signals and one of the circularly polarized wave signals into the set area. The radar apparatus according to claim 1, wherein the setting is performed. 3. An apparatus according to claim 2, further comprising a designation unit for designating a wake of the target, and an oblique polarization generation unit for combining the vertical and horizontal polarization reception signals to generate an oblique polarization signal having a designated polarization angle. 2. The radar apparatus according to claim 1, wherein said signal setting means has means for setting said obliquely polarized wave signal for said wake specified by said specifying means. 4. A plurality of said display means are provided, said area setting means and signal setting means are provided for each display means, and said area and polarization are set individually for each display. The radar device according to claim 1, wherein: