JP2716165B2 - Large, elliptical radar reflector - Google Patents

Description

The present invention relates to an improved and versatile radar reflector. In particular, the present invention relates to improvements in the shape of the outer envelope, the shape of the internal reflectors, and the geometry for suspensions that deploy those reflectors in a precise flat array.

[Conventional technology]

The effectiveness of radar detection is related to the effectiveness of a radar source signal being reflected from an object, ie, a radar reflector. Radar reflectors are used for air and sea rescue, escape from ships, marking temporary runways and indicating danger zones. In such applications, the larger the reflector cross section of the reflector, the better.
It has been found that successful integration of an effective corner reflector array into a versatile device can produce radar cross-sections many times larger than objects of the same size without such a corner reflector array.

Corner reflector arrays are traditionally designed, which provide a very small collapsible, flexible or deflating internal corner reflector, such as in a life vest pocket for easy storage. It is included in an enormous flexible assembly. The corner reflector array is placed in a flexible material that is elastic and does not easily damage. The corner reflector array, located within the versatile flexible envelope, ensures that the reflector will not be distorted or impaired even when subjected to severe use. This versatile reflector can be inflated by mouth, inflated with compressed air, or with a gas lighter than air gas.

[Problems to be solved by the invention]

Prior art prior art patents relate to the design of a versatile corner reflector system. Such examples are described in U.S. Patent Nos. 2,463,517, 3,103,662,
No. 3,115,631. However, due to the versatile configuration of the prior art radar reflector,
The corner reflector array has substantially lost its effectiveness as a radar reflector, especially in today's modern radar systems utilizing short wavelengths.

U.S. Pat.No. 4,673,934 discloses a further improved and versatile radar reflector whose corner reflector array is held flat with the reflectors taut in the appropriate orthogonal direction and yet has a conventional shape. Wrinkles, sagging, twisting and misalignment of angles as seen in technology are greatly reduced. As a result, this versatile radar reflector has a significantly larger radar cross section.

In many versatile radar reflector applications, it is necessary to supply compressed gas to blow in automatically. The weight and volume required for the blow-in system is greater than the weight and volume of the packed radar reflector. For this reason, the vast volume of radar reflectors constitutes a limiting factor in the design. Thus, the effectiveness of the versatile radar reflector is significant when the volume required for a given radar cross section is minimal.

Basically, in all of the versatile radar reflectors of the prior art, a plurality of triangular reflectors are arranged in a tetrahedral array, with eight corner reflectors suspended in a sphere of a versatile outer envelope. It has also been found that such spherical, triangular, and tetrahedral shapes limit the radar cross-section obtained per unit volume.

[Means for solving the problem]

Thus, the present invention relates to an improvement in the shape of the enormous outer envelope of the radar reflector, an improvement in the shape of the reflecting surface suspended therein, and an improvement in the suspension device. The present invention is an improvement over the prior art to reduce the volume required to obtain the same unit cross-sectional area as the prior art of the sphere, and also eliminates sagging and wrinkles and folds that occur on suspended reflective surfaces. Provide improvements such as reduction.

The present invention uses an enormous outer envelope that, when inflated, assumes an elliptical shape. The enormous elliptical outer envelope has a larger surface area per unit volume than the spherical enormous outer envelope. The radar cross section of the internal radar reflector depends on the surface area of the suspended reflector. The effective surface area of the internal reflector increases in the same way as the surface area of the enormous outer envelope. The surface area of a suspended reflector is greater for an ellipsoid than for a sphere of the same volume. For this reason, the elliptical universal envelope of the present invention has a larger radar cross section than the universal radar reflector in the form of a sphere having the same volume.

The radar cross section is further enhanced by the present invention by using non-triangular reflective surface members. The cross-section of the reflector is increased by using a regular quadrilateral, a regular pentagon or, more generally, a regular polygonal reflector. Radar cross section is increased by increasing the area of the reflector surface. A versatile radar reflector with a regular polygonal reflector will have a significantly larger radar cross section than an equal volume versatile radar reflector with a triangular reflector. The polygonal reflector is effective because it has a large surface area and a good stress balance when standing up. Since the reflectors are attached to the inner surface of the versatile outer envelope at two or more points, the stress transmitted from the versatile outer envelope to the reflector is more evenly distributed. Due to this pulling equilibrium in the reflector, the surface is suspended more completely flat and there is little sagging, wrinkling, twisting or other disadvantages.

Each of the reflectors utilized by the present invention is independently suspended within a voluminous envelope by a string, i.e., a pulling device, that wraps around the reflector through a folded seam along the edges of each reflector arranged in the array. You. The lace, i.e. the pulling device, is passed through the edge seam of the reflector, then through the mounting clip device, through another edge seam, through another mounting clip device, etc. and finally the reflector. It will go around all. The mounting clip device may be mounted in a stoma or otherwise mounted on the inner surface of a versatile outer envelope. The reflector is held taut and flat when extended, and levitates to a suitable orthogonal section. This suspension system is greatly enhanced by the introduction of multiple rings spaced along a common adjacent edge of the reflector surface where the notch is cut in the edge seam. These Linders provide stress balance by distributing stress to the reflector structure. This reduces sagging, wrinkling, twisting, and anything that interferes with flat deployment.

〔Feature〕

A major feature and advantage of the present invention is that it significantly increases the radar cross section obtained per unit volume.

Another feature and advantage of the present invention is that the reflective surface of the corner reflector is held more taut and flat, improving the shape of the reflector and reducing the stress of the reflector by using multiple rings at adjacent seams. The good distribution is that wrinkles, sagging and lack of flatness can be significantly reduced.

Another feature and advantage of the present invention is that the laser cross-section is less than that of a reflector that is the same size and shape but has wrinkles, sags, twists, and other lacks of flatness associated with prior art designs. Is to be even greater.

Another feature or advantage of the present invention is that its wrinkling, sagging, or lack of flatness can reduce the wavelength of the radar signal.
A larger radar cross-section for radar systems operating at higher frequencies, ie, shorter wavelengths, than with similar reflectors that exceed 1/6.

Yet another feature and advantage of the present invention is that the elliptical enormous outer envelope is constructed using fewer seams than the spherical enormous outer envelope, which is less expensive to manufacture and more reliable. High, with very little chance of leaking from the seam.

Many other objects and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings.

〔Example〕

FIG. 1 shows a preferred embodiment of the present invention. The corner reflector array 1 includes eight regular pentagonal reflectors 2 each having a reflecting surface on each side, and four regular quadrilateral reflectors.
2a, which are made of, for example, a cloth containing metal, a flexible radar wave reflector such as a metallized film material, laminated foil or saturated rubber. When the reflector members 2, 2a are in place and form a plurality of three-sided corner reflectors, their vertices effectively coincide with the center 3 of the array 1. In the embodiment of FIG. 1, each of the reflectors 2 forms a regular pentagon, two sides are at right angles to each other, and the other three sides coincide with the contour of the ellipse. Each of the reflectors 2a forms a regular quadrilateral, two sides are at right angles to each other, and the other two sides substantially correspond to the major diameter contour of the ellipse. Reflector array 1 has eight three sides (three sides)
Consisting of corner reflectors, their sides are at right angles to each other in effect.

FIG. 2 is a side view showing details of the reflector 2 and the suspension system, and the same reference numerals indicate the same parts throughout these drawings. The reflectors 2, 2a are formed by seams 4 along each outer edge and seams 5 along each inner edge. These marginal seams form passages and enclosures, through which,
String members 6, 6a for causing pulling are passed through. String material 6,
6a also penetrates the mounting clips 7 located at each of the outer vertices of the reflector. This string passes through a ring device 8 located at a notch 9 in the inner edge seam 5 spaced along the adjacent inner edge of the reflector 2, 2a. Each of these ring devices 8 has four segments 6a of lace passing therethrough. That is, each is from each of the four reflectors 2, 2a, which are at right angles to each other and whose edges are adjacent, and thus the four strings at the adjacent edges. For this purpose, a parallel passage is formed. The method for the passage of the laces 6, 6a can be varied using one or more laces. The preferred method is to use 6 strings, of which 3
The book is a perimeter string 6, and each one is turned around the outer edges of the four reflectors 2, 2a in three orthogonal planes, and the remaining three are shaft strings 6a, each of which is three. Pass through adjacent edges of each orthogonal axis. 1 of mounting clip 7
The perimeter string 6 starting from one is passed through the outer edge seam 4, through another mounting clip 7, through another outer edge seam 4, through another clip 7, etc. Circles all of the outer edge seams 4 for all four reflectors 2, 2a. The tie 6a starts from one of the mounting clips 7 located at the end of one of the three orthogonal axes, the inner rim seam 5a.
Through the edge seam in one of the cutouts 9 of the seam, passes through the ring device 8 and then re-enters the edge seam 5 through the notch device 9 and the next to the edge seam 5 , Exits to the next notch device 9, passes through the next ring device 8, enters the notch device again, and finally reaches the mounting clip 7 at the opposite end of the diagonal axis. At this point, the lace has passed through the mounting clip 7 and turned 180 °
A similar passage is completed through the inner edge seam 5 of the individual reflectors 2, 2a and once again passes through the same ring device 8. After four such passes, the edge seam 5 on one axis
Is completed.

The mounting clip 7 is attached to a small hole means (not shown) or to a tab means 11 near the inner surface of the enormous outer envelope 12. The enormous outer envelope 12 may be made of, for example, a polyvinyl chloride film, a polyurethane film, or another plastic film material, a cloth material sealed with rubber, or the like.
It is made of a material that is flexible and impervious to water and air but transmits radar waves. A preferred swellable outer envelope is configured as an ellipse formed of three members as shown in FIG. FIG. 4 is a view showing a case in which a versatile outer envelope is formed by connecting a circular upper member 16 and a circular lower member 17 to a cylindrical member.
It is composed of those joined to 18. In the general case, this versatile envelope, when inflated, will be in the form of a cylinder with top and bottom elliptical caps. The narrower the width of the rectangular member 18, the closer the elliptical end caps will be. If the width of the rectangular member 18 is 0.2133 times the diameter of the circular top member 16 and the circular bottom member 17, the enormous outer envelope, when inflated, will exhibit a true elliptical shape with an eccentricity of 0.866.

FIG. 3 is a graph of the mathematical function for a maximum radar cross section (in square meters) at a provisional wavelength of 3 centimeters (10 gigahertz) for an elliptical radar reflector with eccentricity E. The cross section S of the radar is a dependent variable, and the eccentricity E is an independent variable. The volume of the enormous envelope is standardized to one cubic meter. A spherical, freely variable envelope can be considered as a special case of an ellipse with an eccentricity E = 0. This formula is as follows: That is, This graph shows that the maximum value of the radar cross section corresponds to the eccentricity value of 0.866. The versatile envelope of the preferred embodiment of the present invention is oval with an eccentricity value of exactly 0.866, which optimizes the radar cross section per unit volume.

FIG. 5 shows another preferred embodiment of the universal envelope. In this embodiment, the versatile envelope is formed by only two members. That is, the circular top portion 19 and the same bottom member 20 are formed by joining the two.
When inflated, the envelope assumes an elliptical shape with an eccentricity of 0.707. This is slightly less suitable than the three-piece envelope described above, but has the effect of achieving a maximum radar cross section of 94% and is simpler to manufacture.

When inflating the enormous amount of the outer package 12, the string material 6,6a is pulled tight. Since each reflector 2, 2a is surrounded by a taut string, the reflective surface of the reflector is kept taut and flat, with no folds, loosening or twisting. The cords 6, 6a can slide through the outer edge seam 4, the inner edge seam 5, the ring device 8 and the mounting clip 7,
The lines should be arranged orthogonally. Adjacent inner edge seam 4
Ring devices 8, spaced along, keep the reflectors 2 close to each other, each of which exerts a force which acts to deploy the reflective surface more completely in a completely flat state. Distributing this force to multiple locations along each axis distributes the reflector material stress more evenly,
Thus, loosening, wrinkling, and other imperfections for flat deployment can be further reduced. The accuracy of the angular arrangement of the reflector 2 changes only depending on the positioning accuracy of a small hole (not shown) or the tab 11 in the enormous outer casing 12, and is not determined by the accuracy of the structure of the reflector 2.

Mouth blow valve 13 or compressed gas cartridge 13
By a, gas is introduced into the outer package 12. The type and number of blow valves used depends on whether the inflation operation is performed by mouth, by compressed gas, or by something lighter than air gas. A huge envelope
Attachment 14 is attached to the outside of 12, which is the attachment for line 15. Draw line 15 is for attaching a hugely flexible laser reflector system to a person or object. Similar fittings can also be used for use as a handle or as a particular fixation device.

In the radar reflector of the present invention, the outer envelope is an ellipsoid as described in this specification, so that the internal radar reflector cross-sectional area is irrespective of the direction of the incoming radio wave, and the conventional outer envelope such as a sphere is used. It has a remarkably large area as compared with, and its technical effect as a radar reflector is remarkable.

Although the present invention has been described in terms of a preferred embodiment, the use of identically functioning members and the same flexible array selection principle allows for a wide variety of envelope and reflector shapes. It should also be understood that the radar reflector can be huge. For example, while the preferred embodiment utilizes eight regular pentagons and four quadrilateral reflectors, the number of sides can be increased to achieve a larger, more versatile laser reflector, and so on. Also, the number of ring devices located at seams adjacent to the orthogonal axis can be increased.
The reflectors can all have the same number of sides, but it is also possible to mix reflectors with different numbers of sides, as in the preferred embodiment. The structure of the enormous envelope can be other shapes, such as an ellipse with an eccentric value in an optimal range when inflated. Indeed, many modifications are possible without departing from the spirit of the invention, and the scope of the invention is limited only by the claims.

[Brief description of the drawings]

FIG. 1 is an isometric view of a versatile radar reflector in accordance with a preferred embodiment of the present invention, and FIG. 2 is a schematic view of a corner reflector array forming one of three diagonal surfaces. FIG. 3 is a side view showing details of a suspension system adapted to be suspended. FIG. 3 is a mathematical function for explaining a relationship between a theoretical maximum radar cross section of an elliptical versatile radar reflector and an eccentricity of an ellipse. FIG. 4 is an exploded view of an enormous outer shell showing how an elliptical outer shell is formed in a preferred embodiment of the present invention, and FIG. 5 is an elliptical outer shell. FIG. 5 is an exploded view of a versatile outer envelope showing how a flexible outer shell is formed in another preferred embodiment of the present invention. [Description of Signs] 1 ... Corner reflector array 2,2a ... Reflector 4, ... Outer edge seam 5 ... Inner edge seam, 6,6a ... String material 7 ... Mounting clip, 8 ... Ring device 9 ... Notch, 11 Tab device 12 ... Extensive outer package, 16 Circular top member 17 Circular bottom member, 18 Rectangular member 19 Circular top, 20 Circular bottom 13 Mouth Injection valve by 14 …… Fixture, 15 …… Train

 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-63-20903 (JP, A) JP-A-60-50511 (JP, U) US Patent 4,901,081 (US, A) US Patent 4,673,934 (US, A)

Claims (14)

(57) [Claims] 1. An envelope capable of transmitting radar waves and capable of withering and bulging, and a plurality of radar waves arranged to form a plurality of corner reflectors when the envelope bulges. Exhibiting an elliptical shape surrounding a radar reflective array having a reflector, the reflector being made of a flexible material so that the reflector array is crushed when the outer package is deflated; and When the body swells, each of the reflectors floats on a suspension and is substantially independent of the plane formed by the other reflectors, looking for an optimal flat arrangement, and is mutually orthogonal to that plane. And a suspension supporting said reflectors within said envelope in a manner independent of each other so as to form a surface. Zehnder reflector apparatus. 2. One or more of said reflectors has the shape of a regular quadrilateral, two sides of which are orthogonal to each other, and the other two sides form an obtuse angle, and the vertex of the obtuse angle is The improved laser reflector device according to claim 1, characterized in that it serves as an additional attachment point to the inner surface of the enormous outer envelope. 3. The reflector has one or several regular pentagonal shapes, of which two sides are orthogonal to each other and the other three sides form two obtuse angles, 2. The improved radar reflector device according to claim 1, wherein a vertex of the outer reflector serves as an additional attachment point for an inner surface of the outer envelope. 4. One or several of said reflectors have the shape of a regular polygon, of which two sides are orthogonal to each other, the other sides form an obtuse angle, and the vertex of the obtuse angle is The improved radar reflector device according to claim 1, characterized in that it serves as an additional attachment point to the inner surface of the enormous outer package. 5. An edge of each of said reflectors is provided with a vertical seam, and said reflector array passes through a seam of a reflector among said reflectors from an inner surface of said outer package, and said central portion of said reflector device. By means of a stringing device that passes through the other seam of the reflector and then back to the inner surface of the outer envelope, the reflector seam where the seam is suspended parallel to each other is suspended in the outer envelope. The seam is provided with a notch device, and the string coming from each of the parallel seams is disengaged from the seam notch device and sent through the ring device, and then at the notch device so as to return to the seam. And all the laces crossing the parallel seam are sent through the same ring device and Characterized in that it is pulled together at the location, improved radar reflector according to claim 1. 6. Each of said reflectors is in the form of a regular polygon, two inner sides of which are orthogonal to each other,
The other plurality of outer sides form an obtuse angle, and the apex of the obtuse angle is disposed adjacent to the inner surface of the outer package, and a vertical seam is formed along each of the sides. , Which is connected to the inner surface of the outer envelope, wherein the lace assembly part passing through the seam inside the reflector intersects in a substantially orthogonal relationship at the center of the outer envelope. The improved radar reflector device according to claim 1, characterized in that: 7. The improved radar according to claim 6, wherein said string device portion passing through said outer side seam of said reflector is connected to a mounting device mounted on an inner surface of said outer casing. Reflector device. 8. There are twelve reflectors forming eight trihedral corner reflectors, said reflectors being arranged in three sets, one set and four, forming three mutually orthogonal surfaces. The improved radar reflector device according to claim 7, wherein: 9. The ligature device comprises six laces, three of which are peripheral laces, each of which comprises a set of four reflectors forming said three mutually orthogonal surfaces. Sent around the outer edge through the seam, the other three are ties, each of which is sent through the seam on the adjacent reflector side along each of the three orthogonal axes The improved radar reflector device according to claim 8, characterized in that: 10. The outer envelope is composed of three members, the top member and the bottom member are each joined to a rectangular member, and the rectangular member is joined at both ends to form a cylindrical body. The improved radar reflector device according to claim 1, characterized in that when inflated, it takes the shape of a cylinder with an oval end cap. 11. The outer package body comprises three members, of which:
The top member and the bottom member are each joined to a rectangular member, and the rectangular member is joined at its ends to form a cylinder, the width of which is about 2/10 or less the diameter of the circular member, The improved radar reflector device according to claim 1, wherein the outer envelope has an elliptical shape when inflated. 12. The improved radar reflector according to claim 1, wherein the enormous outer envelope comprises two members joined together, and the outer envelope assumes an ellipsoidal shape when inflated. apparatus. 13. The improved radar reflector device according to claim 1, wherein the outer envelope is configured to assume an ellipsoidal shape having an eccentricity value of 0.70 to 0.95 when inflated. . 14. The improved radar reflector device according to claim 13, wherein the eccentricity of the ellipsoid is substantially close to 0.866.