JPH04341002A - Corner reflector for radar - Google Patents

Abstract

PURPOSE:To reduce a defect area of radar finding by changing a pattern of an azimuth polar coordinate diagram of the corner reflector for rader from four petals into six petals. CONSTITUTION:Three radio wave reflecting plates comprising a radio reflecting plate made up of upright plates A11, D14, a radio reflecting plate made up of upright plates B12, D14, and an equator plate 10 are made orthogonal to form a reflection body 2 having light corner reflectors A41, B42, C43, D44, E45, F46, G47 and H48. The reflection body 2 is mounted to a pole 3 by tilting the three radio reflection plates by 45 deg. transmission with respect to a horizontal plane. The six corner reflectors B42, C43, D44, E45, F46, and H48 have respectively a radar cross sectional area with respect to a plane wave of a radar radio wave made incident in the horizontal direction and the azimuth polar coordinate diagram of the corner reflector 1 shows a six petal pattern.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a radar corner reflector that is attached to a small target such as a small ship or a structure on the sea and serves to enhance the reflection of radar radio waves.

0002

2. Description of the Related Art A corner reflector 50 shown in FIG.
As shown in Japanese Patent Application Laid-Open No. 61-93697, this is an example of a conventional radar corner reflector having eight corner reflectors formed by three radio wave reflecting plates orthogonal to each other. Figure 4 shows the disassembled state.
is shown.

The circular equatorial plate 51 of the corner reflector 50 is made of a high-density polyethylene plate with aluminum foil heat-sealed on both sides to serve as radio wave reflecting surfaces. A total of 8 rectangular holes 59 are penetrated at equal pitches, 4 each, symmetrically with respect to the center point, and from both ends of the diameter perpendicular to the diameter where the rectangular holes 59 are lined up, respectively, toward the center of the equatorial plate 51. A slit 58 is opened to half the length of the radius, and the width of the slit 58 is the same as the thickness,
The shapes of the rectangular holes 59 are all the same, and are shaped so that the largest cross-sectional area portion of the protrusion 56 of the semicircular plate a52 is inserted densely.

[0004] The substantially semicircular semicircular plates a52 and b53, which are made of the same material as the equatorial plate 51 and have radio wave reflecting surfaces on both sides, each have a diameter that is the same length as the diameter of the equatorial plate 51. from the midpoint of the diameter section 60 to the diameter section 60.
0 toward one end of the projection 56, a semicircular recess 57,
Irregularities are formed in the order of the protrusion 56 and the recess 57, and the pitch of the recesses and recesses is the same as the pitch of the rectangular holes 59 of the equatorial plate 51. Recesses and recesses are formed in the order of the recess 57, the protrusion 56, the recess 57, and the protrusion 56, and the pitch of the recesses and recesses is the same as the pitch of the rectangular holes 59 of the equatorial plate 51, and the shape of the recess 57 is as follows.
The shape allows the projections 56 to be inserted tightly.

Further, each of the semicircular plates a52 and b53 has four rectangular holes 59 extending from the midpoint of the diameter portion 60 to a straight line orthogonal to the diameter portion 60. The shape and pitch of the holes 59 are the same as the shape and pitch of the rectangular holes 59 of the equatorial plate 51.

The semicircular plate a52 has a protrusion 56 inserted into a rectangular hole 59 of the equatorial plate 51 on one side of the equatorial plate 51 so that the midpoint of the diameter portion 60 and the center of the equatorial plate 51 coincide. The semicircular plate b53 is attached perpendicularly to the equatorial plate 51 on the other side of the equatorial plate 51.
The protrusion 56 is inserted into the rectangular hole 59 of the equatorial plate 51 and is attached perpendicularly to the equatorial plate 51, and the semicircular plate a52
The protrusions 56 and recesses 57 of the and semicircular plates b53 are integrally coupled with each other by convex-concave fitting to form one radio wave reflecting plate.

[0007] The semicircular plate c54 and the semicircular plate d55, which are made of the same material as the semicircular plate a52 and have radio wave reflecting surfaces on both sides, are each made by removing the rectangular hole 59 from the semicircular plate a52 and adding a slit 58. The slit 5
8 is opened along a straight line perpendicular to the diameter part 60 from the midpoint of the diameter part 60 to the midpoint of the straight line, and has a width equal to the thickness of the equatorial plate 51.

[0008] In the semicircular plate c54, the slit 58 is connected to the equatorial plate 5.
The protrusions 56 are inserted into one slit 58 of 1, and inserted into the rectangular holes 59 of each of the semicircular plates a52 and b53 attached to the equatorial plate 51. Each semicircular plate d55 is attached perpendicularly to the disk b53, and the slit 58 of the semicircular plate d55 is inserted into the other slit 58 of the equatorial plate 51, and the semicircular plate d55 is attached to the equatorial plate 51. rectangular hole 5
9, the protrusion 56 is inserted into the equatorial plate 51 and the semicircular plate a52.
and semicircular plate b53, respectively, and the semicircular plate c54 and the semicircular plate d55 are attached to the respective protrusions 3.
6 and the recess 37 are integrally coupled with each other by concave-convex fitting, and the 1
It forms two radio wave reflecting plates.

[0009] The equatorial plate 51 further has a shape on the center line of the sector in one of the four sector shapes divided by two diameters, the diameter where the rectangular holes 59 are lined up and the diameter where the slits 58 are lined up. A circular hole 69 is penetrated at a position close to the arc of the large sector, and a string 70 is attached to the hole 69.

Corner reflector 5 configured as described above
0 is the equatorial plate 5 that is orthogonal to each other, as shown in FIG.
1. Corner reflectors a61 and e65 are formed by semicircular plate b53 and semicircular plate d55, and corner reflectors b62 and f66 are formed by equatorial plate 51, semicircular plate a52, and semicircular plate c54, which are orthogonal to each other. Equatorial plate 51, semicircular plate a52 and semicircular plate d5
Corner reflectors c63 and g67 are formed by 5, and corner reflectors d64 and h68 are formed by the equatorial plate 51, semicircular plate b53, and semicircular plate d55, which are perpendicular to each other, and a total of eight corner reflectors are formed.

The corner reflector 50 is attached to a small target such as a small ship or a structure on the sea with a string 70, and is used suspended as shown in FIG. The radio wave reflecting surface formed by semicircular plate a52 and semicircular plate b53 and the radio wave reflecting plate formed by semicircular plate c54 and semicircular plate d55 are perpendicular to the horizontal plane. It is tilted at 45 degrees.

For this reason, the horizontal radar cross-sectional area of the corner reflector 50 is measured, and the plane wave of the radar radio wave incident on the reflector 50 corresponds to the equatorial plate 51 in FIG.
If the angle perpendicular to the left side of the plane is 0 degrees, and the incident direction of the radar radio waves is changed counterclockwise in Fig. 3 and expressed in a polar coordinate diagram, the radar cross section will be as shown in Fig. 5. The radar radio waves show peaks at two horizontal angles of 0 degrees and 180 degrees, where they are reflected by 180 degrees by the equatorial plate 51, and at 90 degrees, where the radar radio waves are reflected by 180 degrees by the semicircular plates b53 and d55. Horizontal angle and semicircular plate b5
A peak is also shown at a horizontal angle of 270 degrees, where the radar radio waves are reflected 180 degrees by the corner reflector 50 and the semicircular plate d55, but at the four horizontal angles, the radar radio waves incident on the corner reflector 50 are all directed in the same direction. Since it is reflected, if the radar radio wave deviates even slightly from the horizontal angle, the radar cross-sectional area decreases rapidly.

By the way, a corner reflector consisting of three radio wave reflecting plates perpendicular to each other detects radar radio waves that are incident from all angles around the point where the three radio wave reflecting plates of the corner reflector intersect. For plane waves, the three radio wave reflecting plates have a radar cross-sectional area at a solid angle that simultaneously reflects radar radio waves, and the radar cross-sectional area shows a peak at the center angle of the solid angle.

For this reason, the corner reflector 50 has four corner reflectors c63, d64, e65 and f66 for plane waves of radar radio waves incident from the horizontal direction.
Each of the corner reflectors has a horizontal angle such that the three radio wave reflecting plates constituting each corner reflector simultaneously reflect radar radio waves. That is, the above 4
The corner reflectors are 45 degrees, 135 degrees, 22 degrees
The radar cross section shows a peak corresponding to each of the four angles of 5 degrees and 315 degrees, and the radar cross section continues to exist at the horizontal angle that each corner reflector has.

Therefore, the azimuthal polar coordinate diagram of the radar corner reflector 50 is a four-valve pattern having four broad patterns as schematically shown in FIG. There was a problem in that radar detection was poor in the area h.

Furthermore, since the radar corner reflector 50 is assembled as described above, it can be easily assembled at the installation site, but there is a problem in that the assembly strength is low.

[0017]

SUMMARY OF THE INVENTION In view of the above problems of the prior art, an object of the present invention is to provide a corner reflector for radar that solves the following problems.

(a) By increasing the number of corner reflectors that effectively act on radar radio waves incident from the horizontal direction from four to six, while maintaining the structure having eight corner reflectors. To reduce the area where radar detection is poor in all horizontal directions of a corner reflector for radar.

(b) Increase assembly strength.

[0020]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a three
The center points of the two radio wave reflectors are aligned,
and eight corner reflectors are formed so as to be orthogonal to each other, and two of the eight corner reflectors are located in a point symmetrical position with respect to a point shared by the three orthogonal radio wave reflecting plates. In the corner reflector shown in FIG.
The configuration is such that two radio wave reflectors are rotatably supported on a vertical axis passing through a common point, and one main radio wave reflector is divided into two sub-wave reflectors.
The reinforcement plate and the outermost edge of the radio wave reflection plate piece are connected by screws, which are connected together by concave-convex fitting through the through-hole of the main radio wave reflection plate.

[0021]

[Operation] Since the present invention has the above structure, each of the three radio wave reflecting plates is inclined with respect to the horizontal plane. Therefore, six of the eight corner reflectors formed by the three radio wave reflecting plates have a radar cross-sectional area for the radar radio waves incident from the horizontal direction, and the azimuthal polar coordinate diagram 6 patterns
Since the pattern is a valve pattern, the area of poor detection by the radar is reduced in all horizontal directions.

Furthermore, since the present invention has the above-mentioned configuration, when an external force such as wind is applied, the external force can be deflected by rotating. Therefore, together with the reinforcement by the reinforcing plate, it is durable.

Furthermore, since the present invention has the above configuration and structure, it is easy to assemble and disassemble each component such as the main and sub radio wave reflecting plates. Therefore,
It can be transported to the assembly site in a disassembled state, and it can be easily assembled at the assembly site.

[0024]

[Embodiment] An example of the implementation of claims 1 and 2 is as follows:
1, and FIG. 2 shows an exploded state of the reflector 2 of the corner reflector 1, the top plate 15, which is a reinforcing plate, and the bottom plate 16.

In FIG. 2, the equatorial plate 10, which is the main radio wave reflecting plate of the reflector 2, is made of square high-density polyethylene and has four sides, side A28, side B29, side C30, and side D31, and is covered with aluminum foil on both sides. is thermally welded to make both sides serve as radio wave reflecting surfaces, the four corners are chamfered roundly, and an elongated hole 24 is provided in the center along an arbitrary diagonal line.
4 has both ends of a semicircle and a straight line part connecting both ends.

[0026] Furthermore, the equatorial plate 10 has side A28 and side C30.
Along the center line, a total of six rectangular holes 25, three through holes, are opened from the midpoint of the center line toward side B29 and side D31 at equal pitches, and side B29 and side D3
Even along the center line with 1, from the midpoint of the center line to rectangular hole 2
5 are opened at equal pitches toward side A28 and side C30, three in total, six in total. All pitches and shapes of the rectangular holes 25 are the same, and the shape of the rectangular holes 25 is as follows.
The rectangular protrusions 21 of the same shape each of the upright board A11, the upright board B12, the upright board C13, and the upright board D14 have are shaped to be densely inserted.

The upright board A11 and the upright board C13, which are made of the same material as the equatorial board 10 and have radio wave reflecting surfaces on both sides, have a long side that is the same length as one side of the equatorial board 10, and a long side that is the same length as one side of the equatorial board 10, respectively. A semicircular recess 23 is formed at the center of one of the long sides, and the short side extends perpendicularly to the midpoint of the other long side. A slit 20 is formed up to half the length, and the width of the slit 20 is the same as the thickness of each standing board.

In addition, the two corners of the standing board A11 and the standing board C13, each formed by the long side having the slit 20 and the two short sides, are rounded and chamfered, and the long side having the semicircular recess 23 has a chamfered shape. A rectangular recess 22, a rectangular projection 21, and a rectangular recess 22 are formed in this order from the semicircular recess 23 toward one short side, and from the semicircular recess 23 toward the other short side, the rectangular projection 21, rectangular recess 22, Recesses and recesses are formed in the order of the rectangular protrusions 21, and the pitch of each recess and recess is the same as the pitch of the rectangular holes 25 of the equatorial plate 10. The shapes of the rectangular recesses 22 and the rectangular protrusions 21 of each standing plate are the same, and the rectangular recesses 22 are shaped so that the rectangular protrusions 21 penetrate through the rectangular holes 25 of the equatorial plate 10 and are tightly inserted. .

The upright board A11 has a semicircular recess 23 on one side of the equatorial board 10, and the midpoint of the long side has a semicircular recess 23 and the equatorial board 10
The rectangular protrusion 21 is aligned with the equatorial plate 1 so that the center point of
It is inserted into the rectangular hole 25 of No. 0 and is attached perpendicularly to the equatorial plate 51. In addition, the standing board C13 is the equatorial board 1
0, the rectangular protrusion 21 is inserted into the rectangular hole 25 of the equatorial plate 10, arranged symmetrically with the upright plate A11 with respect to the center point of the equatorial plate 10, and is perpendicular to the equatorial plate 10. The rectangular recesses 22 and rectangular protrusions 21 of the upright plates A11 and C13 are integrally coupled with each other by concave-convex fitting to form one sub-radio wave reflecting plate.

[0030] The standing board B12 and the standing board D14 are each
It is made of the same material as the equatorial plate 10 and has radio wave reflecting surfaces on both sides, and is made to have the same shape as the standing plate A11 except for the slit 20. It is opened parallel to the length of the short side up to half the length of the short side. The width of the slit 20 is the same as the thickness of each vertical plate.

[0031] The slit 20 of the vertical plate B12 is the same as that of the vertical plate A11.
The rectangular protrusion 21 is inserted into the rectangular hole 25 of the equatorial plate 10 and is vertically attached to the equatorial plate A11 and the equatorial plate 10, respectively. Further, the upright board D14 is arranged point-symmetrically with the upright board B12 with respect to the center of the equatorial board 10 on the surface of the equatorial board 10 to which the upright board C13 is attached, and the slit 20 is mutually connected to the slit 20 of the upright board C13. The rectangular protrusions 21 are inserted into the rectangular holes 25 of the equatorial plate 10, and are attached perpendicularly to the equatorial plate C13 and the equatorial plate 10, respectively. This means that the respective rectangular recesses 22 and rectangular protrusions 21 are integrally coupled with each other by concave-convex fitting to form one sub-radio wave reflecting plate.

Corner reflector 1 configured as described above
As shown in FIG. 1, the reflector 2 includes a sub-radio wave reflecting plate consisting of a standing plate A11 and a standing plate C13, a sub-radio wave reflecting plate consisting of a standing plate B12 and a standing plate D14, and an equatorial plate which is a main radio wave reflecting plate. Since the three radio wave reflecting plates 10 have their center points coincident with each other and are perpendicular to each other, the point shared by the three radio wave reflecting plates becomes the center point of the reflector 2, and the center point of the top plate 15 The elongated hole 24 and the semicircular recesses 23 of the standing boards A11, B12, C13, and D14 are all reflectors 2.
Since they are gathered at the center point of the reflector 2, a space 32 is formed at the center point of the reflector 2.

Further, the reflector 2 of the corner reflector 1 configured as described above includes the corner reflectors A41 and B.
42, C43, D44, E45, F46, G47 and H
48 corner reflectors in total, including corner reflectors A41, B42, C43 and D44.
are the equatorial board 10, the standing board A11, and the standing board B12, respectively.
corner reflectors E45, F46, G4.
7 and H48 are each formed by a radio wave reflecting plate piece of three radio wave reflecting plates: the equatorial board 10, the upright board C13, and the upright board D14.

The corner reflector A41 and the corner reflector G47 are located symmetrically with respect to the center point of the reflector 2, and the three corner reflectors forming each corner reflector are
The outermost ends of the radio wave reflecting plate pieces are each bent outward at 45 degrees, and the holding portion 26 has the same shape as a right-angled isosceles triangle.
are formed at six locations in total, and a hole 27 is provided through the center of each holding portion 26. The size of hole 27 is
They are all the same and have a size that allows the female screw 18 to be tightly fitted.

As shown in FIG. 2, a triangular top plate 15 made of hard polyethylene is attached to each of the three corner portions 26 of the corner reflector A41.
In each corner of the top plate 15, a hole 33 of the same size as the hole 27 of each holding portion is bored at a position corresponding to the hole 27. Top plate 15 which is a reinforcing plate
In this case, a plastic female screw 18 is fitted from the top plate 15 side from the hole 33 to the hole 27, and a plastic male screw 19 inserted from the holding part 26 side is pushed into the female screw 18 and screwed together. Corner reflector A4
1, the equatorial board 10, the standing board A11 and the standing board B
12 are joined together. Further, the top plate 15 has a square packing 17 made of hard polyethylene adhered to the center of the outer surface, and a hole 34 passing through the packing and the top plate 15 is bored in the center. The size of the hole 34 is
The diameter is set to be slightly larger than the diameter of the pole 3 inserted through the space 32 of the reflector 2.

A base plate 16 made of the same material and having the same shape as the top plate 15 is attached to the three holding portions 26 of the corner reflector G47 by the same method as the top plate 15. The base plate 16, which is a reinforcing plate, is connected to the equatorial plate 10,
The vertical plate C13 and the vertical plate D14 are integrally combined, and a gasket 17 made of the same material and having the same shape as the gasket 17 of the top plate 15 is glued to the center of the outer surface, so that it is the same as the gasket 17 of the top plate 15. A diameter hole 34 is provided through the center.

By the way, the female screw 18 and the male screw 19 are
They have the characteristic that they are screwed together simply by pushing them into each other, and can be removed by rotation. Therefore, no tools are required for the work of attaching the top plate 15 and the base plate 16 to the reflector plate 2 of the corner reflector 1, and the work can be easily performed on site.

The pole 3 inserted through the hole 34 of the top plate 15, the hole 34 of the base plate 16, and the space 32 of the reflector 2 is
It is made of hollow vinyl chloride, and one end has a hole A35 and a hole B (not shown) perpendicular to the center line in the longitudinal direction, and the distance between the holes A35 and B is the same as that of the reflector. The reflector 2 to which the top plate 15 and bottom plate 16 are attached is set to be slightly longer than the distance between the outer surfaces of the respective packings 17 of the top plate 15 and bottom plate 16 attached to
The hole A35 and the hole B are arranged between the hole A35 and the hole B.
It is held on the pole 3 by split pins 36 inserted into the respective parts, and is rotatably supported on the pole 3.

Although the corner reflector 1 of the embodiment is constructed as described above, the shape and material of the equatorial plate 10 etc. which are the constituent elements of the corner reflector 1 are not limited to those of the embodiment.

Corner reflector 1 configured as described above
When the pole 3 is installed perpendicularly to the horizontal plane, the top plate 15 and the bottom plate 16 become parallel to the horizontal plane, respectively, as shown in FIG. 1, and the vertical plate A11 and the vertical plate C13
The sub-radio wave reflecting plates formed by the vertical plate B12 and the vertical plate D
The three radio wave reflecting plates, the auxiliary radio wave reflecting plate formed by the auxiliary radio wave reflecting plate 14 and the equatorial plate 10, are each inclined at 45 degrees with respect to the horizontal plane.

Therefore, for plane waves of radar radio waves incident from the horizontal direction, the corner reflectors B42 and C
The six corner reflectors 43, D44, E45, F46, and H48 each act effectively as a corner reflector and have a radar cross-sectional area at a horizontal angle centered on the pole 3, so the orientation of the corner reflector 1 The polar diagram results in a six-valve pattern, an example of which is schematically illustrated in FIG. 6, which reduces the area of poor radar detection when compared to the four-valve pattern of a conventional corner reflector 50, illustrated schematically in FIG.

By the way, the corner reflector 1 of the embodiment is as follows:
The pole 3 is installed perpendicularly to the horizontal plane, and the three radio wave reflecting plates forming the eight corner reflectors each have an inclination angle of 45 degrees with respect to the horizontal plane. There is no need for the three radio wave reflecting plates to be unified, and the angle is not limited to 45 degrees. However, since the reflection efficiency of the corner reflector 2 is highest when all the inclination angles are set to 45 degrees, it is preferable that all the inclination angles are set to 45 degrees.

The reflector 2 of the corner reflector 1 of the embodiment is as follows:
The standing board A11 and the standing board B12 are connected to the equatorial board 1 by the top board 15.
0, the upright plate C13 and the upright plate D14 are connected to the equatorial plate 10 by the base plate 16, and all the upright plates are connected to one equatorial plate 10, so that the conventional corner reflector of FIG. The assembly strength is greater than that of 50.

In the corner reflector 1 of the embodiment, the reflector 2 to which the top plate 15 and the base plate 16 are attached is rotatably supported on the pole 3, so that it can be rotated even when subjected to external forces such as wind. Can absorb external forces. Therefore, together with the reinforcement of the reflector 2 by the top plate 15 and the bottom plate 16, it is durable.

Furthermore, since the corner reflector 1 of the embodiment has the above-described structure, it can be easily assembled from each component such as the equatorial plate 10, and also easily disassembled into each component. Therefore, it can be transported to the assembly site in a disassembled state, and it can be easily assembled at the assembly site.

[0046]

[Effects of the Invention] Since the present invention has the above-described configuration and operation, the area of poor detection by radar is reduced in all horizontal directions, is durable, and can be transported to the assembly site in a disassembled state. This has the effect that it can be easily assembled at the assembly site.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an example of implementation of claims 1 and 2.

FIG. 2 is an exploded perspective view of a reflector, a top plate, and a base plate among those shown in FIG. 1.

FIG. 3 is a perspective view showing an example of a conventional product.

FIG. 4 is a partially exploded perspective view of the device shown in FIG. 3;

5 is a schematic illustration of an example of an azimuth polar diagram of that shown in FIG. 3; FIG.

6 is a schematic representation of an example of an azimuthal polar diagram of the one shown in FIG. 1; FIG.

[Explanation of symbols]

1 Corner reflector 2 Reflector 3 Pole 10 which is the axis Equatorial plate 11 which is the main radio wave reflecting plate Standing plate A12 forming the sub radio wave reflecting plate Standing plate B13 forming the sub radio wave reflecting plate Standing board forming the sub radio wave reflecting plate Plate C14 Standing plate D15 forming a secondary radio wave reflecting plate
Top plate 16 as a reinforcing plate Base plate 18 as a reinforcing plate Female screw 19 Male screw 25 Rectangular hole 41 as a through hole Corner reflector A 42 Corner reflector B 43 Corner reflector C 44 Corner reflector D 45 Corner reflector E 46 Corner reflector F 47 Corner reflector G 48 Corner reflector H

Claims (2)

[Claims] [Claim 1] Eight corner reflectors are formed by three radio wave reflecting plates of the same shape having flat radio wave reflecting surfaces on both sides, with their center points aligned and perpendicular to each other. , in two corner reflectors among the eight corner reflectors located point-symmetrically with respect to a point shared by the three orthogonal radio wave reflecting plates, each three pieces forming the two corner reflectors; The outermost ends of the radio wave reflecting plates are each integrally connected by a reinforcing plate, and are rotatable about a vertical axis passing through the center point of both reinforcing plates and the point shared by the three orthogonal radio wave reflecting plates. Corner reflector for radar supported by. [Claim 2] Two sub radio wave reflectors are each divided into two parts for one main radio wave reflector, and are integrally joined by concave-convex fitting through the through holes of the main radio wave reflector, The radar corner reflector according to claim 1, wherein the reinforcing plate and the outermost end of the radio wave reflecting plate piece are screwed together.