An deployable-retractable RCS adjustable reflector and its control method

Abstract

The present invention discloses an expandable-foldable RCS adjustable reflector and a control method thereof. The reflector comprises a layer of reflector components and another layer of reflector components arranged in a mirror image, each reflector component comprises n reflector units connected to each other, and n is a positive integer greater than or equal to 6; the two layers of reflector components are correspondingly hinged through n supporting points of each layer to form a movable structure; each layer of reflector components is provided with an expansion-folding mechanism, which is used to expand or fold the expandable-foldable RCS adjustable reflector as a whole about an expansion-folding axis, and the expansion-folding axis is a line passing through the centers of two joint interface diameter surfaces, and the RCS is controlled by different expansion degrees of the joint interface diameter surfaces. The problem that the product structure volume is fixed, RCS control cannot be performed, or RCS control within a very small range in the prior art is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of radars, and in particular relates to an expandable and retractable RCS adjustable reflector and a control method thereof. Background Art

[0002] As the current electromagnetic environment becomes more and more complex, electronic countermeasures are developing faster and faster, and the development of reflectors is gradually unable to keep up with the pace of demand. Existing reflector products often have fixed sizes, volumes and large weights. They are troublesome and bulky in use and transportation, and cannot meet the requirements of easy transportation and loading and lightweight. Moreover, when the size and volume are fixed, they often do not have the ability to control RCS, and cannot meet the requirements for different scattering characteristics in today's complex electromagnetic environment and the requirements for convenient use, transportation and loading.

[0003] Some existing reflector products mostly use metal planes or other materials as the reflective surface, and arrange multiple reflector units. Once they (existing reflector products) have a certain structure, it is difficult to change them. As a result, the overall weight is large, and the excessive volume brings great difficulties to use, transportation and loading.

[0004] There are a few reflector products that have the ability to control RCS, but they generally have complex structures and large volumes, and the range of control is very small. The reason is that the volume and structure are fixed. For existing reflector products, when different scattering characteristics need to be achieved, different reflector products need to be selected. If the traditional method is still used, it cannot meet the complex and changeable requirements for scattering characteristics, resulting in the problem of not being able to change the target scattering characteristics in time. Therefore, the shortcomings of existing reflectors are that the product structure and volume are fixed, RCS control cannot be performed, or RCS control is limited to a very small range. Summary of the invention

[0005] The object of the present invention is to provide an expandable and retractable RCS adjustable reflector and a control method thereof, so as to solve the problem in the prior art that the product structure volume is fixed, RCS control cannot be performed or RCS control is performed within a very small range.

[0006] The present invention adopts the following technical solution: an expandable and retractable RCS adjustable reflector, comprising a layer of reflector components and another layer of reflector components arranged in a mirror image therewith, each reflector component comprising n reflector units connected to each other, where n is a positive integer greater than or equal to 6;

[0007] Each reflector unit is a triangular trihedral corner reflector, each reflector unit has an aperture surface with an open top and a side surface equipped with a metal wire mesh, the three endpoints of each aperture surface are boundary vertices, the vertex of each reflector unit is a support point, adjacent boundary vertices are hinged through two upper chord rods, adjacent boundary vertices and support points are connected through support rods, and the two upper chord rods are connected by a folding joint to form a foldable structure;

[0008] The connection form of the n reflector units is: six reflector units are spliced ​​to form a regular hexagonal splicing interface diameter surface with the same aperture opening direction; or, with the regular hexagonal splicing interface diameter surface as the center, the remaining reflector units are sequentially and alternately connected at each boundary vertex outside the central regular hexagon in positive and negative directions until the splicing interface diameter surface forms a regular polygon;

[0009] The two layers of reflector components are hinged correspondingly through n supporting points of each layer to form a movable structure;

[0010] Each layer of reflector assembly is provided with an expansion-folding mechanism, which is used to expand or fold the expandable-foldable RCS adjustable reflector as a whole about the expansion-folding axis. The expansion-folding axis is a line passing through the centers of the two joint diameter surfaces. The RCS is controlled by different expansion degrees of the joint diameter surfaces.

[0011] Furthermore, the unfolding-folding mechanism on each layer of reflector assembly includes:

[0012] A plurality of roller joints (10) are located at each boundary vertex of the outermost circle of the joint diameter surface, and include a roller structure and a movable sleeve structure; wherein the roller structure includes a U-shaped roller support, and a pin shaft and a roller are arranged in parallel and at intervals at the opening of the roller support, and a threading gap is left between the pin shaft and the roller; and the movable sleeve structure has a plurality of sleeves for being respectively hinged to the upper chord rod and the support rod;

[0013] A thin metal rope, one end of which is fixed to any one of the roller supports, and the other end of which passes through the threading gaps of each roller support in turn, and is finally led out from the threading gap in the roller support to which the thin metal rope is fixed;

[0014] A stepping motor is connected to the lead-out end of the thin metal rope and is used to drag the thin metal rope through its external force so as to shrink the diameter surface of the joint.

[0015] Furthermore, the size ratio of the upper chord and the support rod is 1:1.477. In the fully deployed state, the angle between adjacent upper chords and support rods is 45°, and the angle between every two support rods is 90°.

[0016] Furthermore, adjacent connections between upper chord rods and upper chord rods, adjacent connections between upper chord rods and support rods, and adjacent connections between support rods and support rods are hinged by a joint structure made of aluminum-magnesium alloy.

[0017] Furthermore, when n=6, the boundary vertices of the six reflector units are connected to each other, and the six aperture surfaces are spliced ​​into a regular hexagon with the same opening direction.

[0018] Furthermore, the upper chord rod and the support rod are hollow carbon fiber rods.

[0019] Furthermore, the metal wire mesh is gold-plated molybdenum wire, gold-plated iron wire or stainless steel wire, the wire diameter of the metal wire mesh is 0.02mm-0.5mm, and the mesh diameter is 3mm-10mm.

[0020] The second technical solution adopted by the present invention is a control method of an expandable-foldable RCS adjustable reflector. Based on an expandable-foldable RCS adjustable reflector, the control method includes the following contents:

[0021] Folding process: the thin metal rope is stretched by the driving motor, so that the thin metal rope passing through the roller joint (10) is tightened, and each reflector unit is folded around the expansion-folding axis, and the metal wire mesh is also folded, and the reflector aperture is reduced;

[0022] Unfolding process: The driving motor does not apply external force to the thin metal rope, and each reflector unit unfolds under the reaction of the folding joint, and the metal wire mesh also unfolds to form a reflective surface, and the reflector aperture increases;

[0023] The stretching degree of the thin metal rope is controlled by driving the motor to control the expansion and contraction degree of the splicing interface diameter surface, so that the splicing interface diameter surface can be expanded and contracted to different degrees, and correspondingly different RCSs can be obtained. The RCS can be controlled according to the corresponding relationship between the splicing interface diameter surface and RCS.

[0024] The beneficial effects of the present invention are as follows: the present invention is based on a triangular three-sided corner reflector unit, performs a specific structural design and unit combination to form a specific array structure, the reflector can achieve target scattering characteristics that change according to requirements in different unfolded and folded states, and can also conveniently realize unfolding and folding operations, thereby achieving an RCS control effect. Figure 6 and 7The figure shows the change of RCS curve with frequency under different expansion and contraction degree states (state 1, 2, 3, 4). It can be seen that the RCS adjustable range is up to nearly 30dB, and the control range is large. In addition, the present invention relies on the expansion and contraction mechanism to achieve variable volume operation that traditional corner reflectors cannot achieve, which greatly facilitates the loading, transportation and use of the reflector. For example, when it needs to be transported, the reflector can be completely folded. At the same time, the carbon fiber hollow rod and the metal wire mesh greatly reduce the weight of the reflector, which is not only convenient for loading and transportation, BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of a corner reflector unit of an expandable and retractable RCS adjustable reflector according to the present invention;

[0026] Figure 2 It is a structural schematic diagram of the joint diameter surface of one layer of corner reflector components of an expandable-collapsed RCS adjustable reflector of the present invention when n=6;

[0027] Figure 3 It is a structural schematic diagram of a corner reflector assembly of one layer of an expandable-foldable RCS adjustable reflector of the present invention when n=6;

[0028] Figure 4 It is a schematic diagram of the three-dimensional structure of a combination of two-layer corner reflector components of an expandable and retractable RCS adjustable reflector according to the present invention;

[0029] Figure 5 This is a schematic diagram of the splicing of aperture surfaces of one layer of corner reflector components of an expandable and retractable RCS adjustable reflector of the present invention when n=24;

[0030] Figure 6 Graph showing changes in RCS with frequency when the expansion and contraction degrees are state 1 and state 2 according to an embodiment of the present invention;

[0031] Figure 7 Graph showing changes in RCS with frequency when the expansion and contraction levels are state 3 and state 4 according to an embodiment of the present invention;

[0032] Figure 8 It is a structural schematic diagram of an expandable and retractable RCS adjustable reflector of the present invention from the perspective of the joint interface diameter plane;

[0033] Fig. 9 A schematic diagram of a state in which a thin metal rope of an expandable and retractable RCS adjustable reflector of the present invention passes through a roller joint;

[0034] Fig.10 The present invention is a schematic diagram of an expandable and retractable RCS adjustable reflector in a fully retracted state.

[0035] Among them, 1. upper chord, 2. support rod, 3. boundary vertex, 4. support point, 5. folding joint, 6. thin metal rope, 7. roller support, 8. roller, 9. pin shaft, 10. roller joint. DETAILED DESCRIPTION

[0036] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] The present invention provides an expandable and retractable RCS adjustable reflector, such as Figure 4 As shown, it includes a reflector component and another reflector component mirrored thereto, such as Figure 3 As shown, each layer of reflector assembly includes n reflector units connected to each other, where n is a positive integer greater than or equal to 6. The structure of the lower layer is the same as that of the upper layer, but is in a mirror-symmetrical relationship with the first layer.

[0038] Each reflector assembly includes n reflector units connected to each other, such as Figure 1 As shown, each reflector unit is a triangular three-sided corner reflector, each of which has an aperture surface with an open top and a side surface with a metal mesh, the three endpoints of each aperture surface are boundary vertices 3, and the vertex of each reflector unit is a support point 4. Specifically, each reflector unit is a triangular pyramid structure with an open bottom surface and three side surfaces, each of which is provided with a metal mesh; the bottom surface is the aperture surface, the three endpoints of the aperture surface are boundary vertices 3, and the vertex of the reflector unit is a support point 4. Each corner reflector unit has a surface composed of three edges of the same length as the aperture surface, and except for the aperture surface, the other surfaces are uniformly covered with metal mesh as a lightweight reflective surface. Adjacent boundary vertices 3 are hinged by two upper chord rods 1 through a folding joint 5, that is, every two upper chord rods 1 are hinged by a folding joint 5 to form a foldable structure. Adjacent boundary vertices 3 and support points 4 are connected by support rods 2. The upper chord rod 1 and the support rod 2 are the supporting framework of the reflector array and can be used as a frame to which the metal wire mesh is attached. At the same time, the upper chord rod 1 is hinged by a folding joint 5 to ensure that the reflector can be unfolded and folded.

[0039] The connection form of n reflector units is: six reflector units are spliced ​​to form a regular hexagonal splicing interface diameter surface with the same aperture opening direction; or, with the regular hexagonal splicing interface diameter surface as the center, the remaining reflector units are sequentially and alternately connected at each boundary vertex 3 outside the central regular hexagon, until the splicing interface diameter surface forms a regular polygon. Wherein, no matter how much the number n of reflector units is, the surface where each aperture surface forming a regular polygon is obtained by splicing each layer is called the splicing interface diameter surface. For the splicing interface diameter surface, the number n of reflector units is at least six, which can be spliced ​​to form a regular hexagon; if n>6, with the regular hexagonal aperture surface as the center, the remaining number of reflector units must just surround the aperture surface at the center to form a regular polygonal splicing interface diameter surface. The number of circles m can be one or more circles.

[0040] To illustrate the arrangement principle of multiple corner reflector units, Figure 5 Taking the aperture surface of the upper array shown in the figure as an example, the arrangement is as follows: the arrangement is centered on a regular hexagon and increases in number of circles, such as Figure 5 The dotted line shows the second circle of corner reflector units. And so on. Each time the corner reflector units are added, they are the outermost circle. When the entire corner reflector array has m circles, the number of corner reflector units is 6m. 2 Since the new corner reflector array proposed in the present invention is a mirror-symmetrical structure of the upper and lower layers, the number of units of the entire corner reflector array is 12m 2 At this time, the position where the thin metal rope driven by the driving motor should pass is the boundary vertex 3 of the outermost circle of the aperture surface.

[0041] The two layers of reflector assemblies are hinged through n supporting points 4 of each layer to form a movable structure. Each layer of reflector assembly is provided with an expansion-folding mechanism, which is used to expand or fold an expandable-foldable RCS adjustable reflector as a whole about an expansion-folding axis. The expansion-folding axis is a line passing through the centers of the two joint surface diameters. The RCS is adjusted by different expansion degrees of the joint surface diameters. The folded state is as follows: Fig.10 As shown, the maximum extent of the unfolding is to make the joint diameter surface become a plane state.

[0042] In some embodiments, Figure 8 As shown, the unfolding-folding mechanism includes a plurality of roller joints 10, a thin metal rope 6 and a stepping motor. The plurality of roller joints 10 are located at each of the boundary vertices 3 of the outermost circle of the splicing interface diameter surface, and include a roller structure and a movable sleeve structure. Fig. 9As shown, the roller structure includes a U-shaped roller support 7, and a pin shaft 9 and a roller 8 are arranged in parallel and at intervals at the opening of the roller support 7, and a threading gap is left between the pin shaft 9 and the roller 8. A movable sleeve structure has a plurality of sleeves respectively hinged to the upper chord rod 1 and the support rod 2. One end of the thin metal rope 6 is fixed to any one of the roller supports 7, and the other end passes through the threading gap of each roller support 7 in turn, and finally leads out from the threading gap in the roller support 7 to which the thin metal rope 6 is fixed. A stepper motor is connected to the lead-out end of the thin metal rope 6, and is used to drag the thin metal rope 6 through its external force so that the diameter surface of the splicing interface shrinks.

[0043] A thin metal rope 6 is inserted between the roller 8 and the pin 9 of the roller joint 10. The thin metal rope 6 is inserted from any boundary vertex 3 on the outer periphery of the splicing interface diameter surface, and is sequentially inserted between the roller 8 and the pin 9 of each roller joint 10 along the outer periphery of the splicing interface diameter surface. After the thin metal rope 6 is wrapped around once, the other end of the thin metal rope 6 is fixed to the initial boundary vertex 3. The thin metal rope 6 on the lower reflector assembly that is mirror-symmetrical with the reflector assembly of this layer is also arranged in the same way. The starting boundary vertex 3 of the fixed thin metal rope 6 on the two layers of reflector assemblies should also be mirror-symmetrical. The retracted shape is achieved by stretching the two thin metal ropes 6 at the same time. The thin metal rope 6 is connected to a driving motor, and the stretching of the thin metal rope 6 is achieved by the driving motor; the sleeve of the movable sleeve structure is hinged at the boundary vertex 3, one end of the sleeve is connected to the upper chord rod 1 or the support rod 2, and the other end is hinged at the boundary vertex 3, so that the upper chord rod 1 or the support rod 2 connected to the sleeve can move with the retraction of the reflector, thereby realizing the operation of unfolding and retracting.

[0044] In some embodiments, the boundary vertex 3 and the support point 4 are connected by a support rod 2, and the size ratio of the upper chord rod 1 and the support rod 2 is 1:1.447. In the fully deployed state, the angle between the adjacent upper chord rods 1 and the support rods 2 is 45°, and the angle between each two support rods is 90°. The deployable-foldable RCS adjustable reflector proposed by the present invention is not limited by its size, and can be enlarged or reduced in proportion to the size of the upper chord rod and the support rod. The ratio of the enlargement or reduction is 1:1.447. After proportional enlargement or reduction, the present invention still has good RCS control effect achieved by deployment-folding and lightweight characteristics.

[0045] In some embodiments, the connection between adjacent upper chord rods 1 and upper chord rods 1, the connection between adjacent upper chord rods 1 and support rods 2, and the connection between adjacent support rods 2 and support rods 2 are hinged by a joint structure made of aluminum-magnesium alloy. Each joint structure includes a main body and a sleeve arranged thereon, and the sleeve and the main body are hinged structures, that is, the sleeve can move within 0°-90°, and the sleeve is used to connect with each upper chord rod 1 and / or support rod 2, and the hinge is realized by the rotation of the sleeve. The movable hinge structure ensures the smooth unfolding and folding of the overall structure of the reflector.

[0046] In some embodiments, Figure 2 As shown, when n=6, the boundary vertices 3 of the six reflector units are connected to each other through the upper chord rod 1 and the folding joint 5, and the six aperture surfaces are located in the same plane and spliced ​​into a regular hexagon with the same opening direction. Because the aperture surface formed by the combination is a regular hexagon, the electromagnetic wave receiving capacity formed in the direction of each aperture surface is equivalent. The present invention includes, but is not limited to, 12 corner reflector units, one or more of which can be taken out and used. Based on the array embodiment composed of 12 units of the present invention, it can still be arranged according to Figure 5 The same corner reflector unit can be added in a two-layer mirror structure, which can also achieve lightweight reflector and RCS control effect by expanding and contracting the reflector. For one or several units, the above technology is still applicable.

[0047] In some embodiments, the upper chord 1 and the support rod 2 are hollow carbon fiber rods, which effectively reduce the weight of the corner reflector array while ensuring high structural strength, making the reflector array lightweight and facilitating loading, transportation and use.

[0048] In some embodiments, the metal mesh is a gold-plated molybdenum wire, a gold-plated iron wire or a stainless steel wire, the wire diameter of the metal mesh is 0.02 mm-0.5 mm, and the mesh diameter is 3 mm-10 mm. The weight of the metal mesh is much smaller than that of a traditional metal reflective surface. The present invention works on electromagnetic waves at a frequency of 2-20 GHz, and through experimental tests, the results obtained can prove that the metal mesh has a reflective effect.

[0049] The present invention provides a control method for an expandable and retractable RCS adjustable reflector:

[0050] Folding process: After the thin metal rope 6 passing through the roller joint 10 is tightened by the driving motor to stretch the thin metal rope 6, each reflector unit is folded around the expansion-folding axis, and the metal wire mesh is also folded, and the reflector aperture is reduced;

[0051] Unfolding process: the driving motor does not apply external force to the thin metal rope 6, and each reflector unit unfolds under the reaction of the folding joint 5, and the metal wire mesh also unfolds to form a reflecting surface, and the reflector aperture increases.

[0052] The stretching degree of the thin metal rope is controlled by driving the motor to control the expansion and contraction degree of the splicing interface diameter surface, so that the splicing interface diameter surface can be expanded and contracted to different degrees, and correspondingly different RCSs can be obtained. The RCS can be controlled according to the corresponding relationship between the splicing interface diameter surface and RCS.

[0053] An expandable-foldable RCS adjustable reflector is expanded or folded as a whole about an expansion-folding axis, and the expansion-folding axis is a line passing through the centers of the two joint diameter surfaces. Different expansion degrees determine the differences in its electromagnetic scattering characteristics, that is, the RCS is regulated by different expansion and folding states. The overall folding of an expandable-foldable RCS adjustable reflector is achieved by driving the thin metal rope 6 to stretch by a stepper motor, and the expansion is achieved by the spring action in the folding joint 5. Usually, the stepper motor is connected to the thin metal rope 6, and the thin metal rope 6 passes through all the boundary vertices 3 of the outermost circle in sequence (these all boundary vertices 3 are the boundary vertices 3 of all the aperture surfaces of the upper and lower layers). During regulation, the two joint diameter surfaces are used as the main scattering surfaces. During the folding process, the stepper motor works to drive the thin metal rope 6 to stretch, so that multiple reflector units are folded under the joint hinge mechanism; during the expansion process, the stepper motor stops working, the thin metal rope 6 relaxes naturally, and multiple reflector units are expanded under the action of the spring in the folding joint 5. Multiple reflector units achieve RCS control through the expansion-contraction process, and the specific target control effect should be determined according to the purpose of use and the electromagnetic environment.

[0054] Example

[0055] The present invention discloses an expandable and retractable RCS adjustable reflector, which includes 12 corner reflector units, wherein the length of the upper chord rod 1 and the support rod 2 of each unit are 213.38 mm and 308.84 mm respectively, and the outer diameter is 5 mm, and the outer diameter of the sleeve used for the hinge in the joint structure is 7 mm and the inner diameter is 5 mm. The reflector support frame is composed of the upper chord rod 1 and the support rod 2 made of carbon fiber hollow rods, and each joint hinge structure, and the reflective surface is fixed on each support rod 2 by a metal wire mesh through a special adhesive.

[0056] Since the upper chord rod 1 and the support rod 2 are both hollow carbon fiber rods, and each articulated joint structure is made of aluminum-magnesium alloy, the metal wire mesh reflective surface ensures the lightweight and high structural strength characteristics of the overall device of the present invention. The usual corner reflector array weighs more than several kilograms or even tens of kilograms because the reflective surface is made of metal, and the size is several meters or even larger. The basic parameters of the embodiment of the present invention are shown in Table 1. The total weight after laying the metal wire mesh is only 1.325Kg, and the folded volume is only 0.004m 3 , indicating that the volume of a deployable and retractable RCS adjustable reflector is very small after being fully retracted, and the deployed volume is 0.325m 3 , the storage rate reaches 81.25%. From Table 1, it can be seen that the deployable-foldable RCS adjustable reflector of the present invention has the advantages of light weight, small folded volume, large deployed volume and high storage rate.

[0057] Table 1 Basic parameters of the reflector in the embodiment

[0058]

[0059] Through experimental testing of this embodiment, it can be learned from the experimental results that the reflector can achieve different scattering characteristics of electromagnetic waves through different expansion and contraction degrees (different states), that is, it realizes the regulation of RCS.

[0060] Based on the above embodiments, an experimental analysis is conducted on four states of an expandable and retractable RCS adjustable reflector of the present invention, and the relationship between RCS (radar cross section) and incident wave frequency in the four expandable and retractable states is obtained, such as: Figure 6 and 7 As shown in the RCS curve. When the required RCS control effect is determined, the RCS change curve under different states can be referred to, and the expansion degree of the reflector aperture surface can be adjusted according to the required RCS. When the reflector is used to interfere with radar detection, the principle is that the reflector frequently and irregularly expands and retracts, that is, constantly changes its own RCS, so that the radar detects the irregularly changing RCS, thereby interfering with its detection.

[0061] Among them, based on the angle formed by the two upper chord rods 1 hinged by the folding joint 5 on the aperture surface of each reflector unit, assuming that the angle is θ, the four unfolding and folding states of an expandable and foldable RCS adjustable reflector are: when θ=180°, it is state 1; when θ=135°, it is state 2; when θ=90°, it is state 3; when θ=45°, it is state 4. The experimental results of the embodiment of the expandable and foldable RCS adjustable reflector are given, the frequency range is 2-20GHz, and after experimental testing, the RCS variation curves with frequency under four unfolding and folding degrees (states 1, 2, 3, and 4) are obtained respectively. In order to present the curves clearly, states 1 and 2, and states 3 and 4 are put together for comparison. Figure 6 The curves of the reflector RCS changing with frequency in state 1 and state 2 show that the reflector has corresponding RCS values ​​at different frequencies, and most RCS values ​​are greater than 10dB, which shows that the reflector has a significant reflection effect. In both states, the reflector RCS is greater than 10dB at most frequency points, which shows that the reflector has the most basic working ability, that is, it can reflect electromagnetic waves. Comparing the curves of the reflector RCS in the two states, it can be seen that the RCS difference in the two states is as high as 25dB at some frequency points, close to 30dB, indicating that the expandable-retractable RCS adjustable reflector can adjust the RCS by switching the state, that is, the stepper motor drives the thin metal rope to make the reflector present different expansion degrees and show the effect of RCS regulation. Figure 7 The curves of the reflector RCS changing with frequency in state 3 and state 4 show that in these two states, the RCS difference in some frequency bands is more obvious, which means that the regulation is effective. By comparing the RCS curves in the above four states, it is also verified that the expandable-retractable RCS adjustable reflector can achieve RCS regulation by adjusting the expansion degree of its own splicing interface diameter surface.

[0062] According to the experimental data of the above embodiments, it can be seen that the control effect of an expandable-foldable RCS adjustable reflector is as follows: when an expandable-foldable RCS adjustable reflector is required to present a large RCS, the whole is adjusted to a corresponding state by the method described, that is, the required scattering characteristics are obtained; when an expandable-foldable RCS adjustable reflector is required to present a small RCS, the whole is adjusted to a corresponding state by the method described. In addition, when an expandable-foldable RCS adjustable reflector is used as an unintentional interference for radar detection, an irregularly changing RCS can be achieved by irregularly switching an expandable-foldable RCS adjustable reflector in different states, thereby interfering with radar detection. It can be seen from the experimental data of the embodiment that the irregular switching in different states has the function of achieving irregular changes in RCS.

[0063] The present invention proposes to use a carbon fiber hollow rod with light weight and high structural strength as the support skeleton of the reflector array. Each joint hinge structure adopts magnesium aluminum alloy to ensure sufficient strength. The woven metal wire mesh is used as the reflective surface. Its elasticity ensures the electromagnetic wave reflection effect of an expandable and retractable RCS adjustable reflector during the expansion and contraction process. These structures also show great advantages in weight, which is much less than the weight of existing reflector products. Among them, the mesh diameter of the metal wire mesh in the embodiment is 5mm, and the experimental test frequency band of the present invention is 2-20GHz. An expandable and retractable RCS adjustable reflector has a reflector effect in this frequency band.

[0064] The present invention is based on a triangular three-sided corner reflector unit. The corner reflector unit has the function of enhancing reflection. In order to make the corner reflector array aperture surface receive the incoming wave to the maximum extent, that is, to make the corner reflector array aperture surface as evenly distributed as possible, the present invention is designed to arrange the corner reflector unit aperture surfaces in a regular polygonal manner, so as to form a considerable electromagnetic wave receiving capability in all directions of the aperture surface. After design, the present invention has been experimentally tested. From the test result data, it can be seen that the expandable-foldable RCS adjustable reflector can select the degree of expansion, that is, different states, according to the different electromagnetic scattering characteristics required, so as to achieve the regulation of RCS in the corresponding state; it can also be achieved by adjusting the expansion degree of an expandable-foldable RCS adjustable reflector to interfere with radar detection, such as the expansion and contraction of an expandable-foldable RCS adjustable reflector with irregular changes.

[0065] The expandable and retractable RCS adjustable reflector of the present invention adopts the expansion and retraction strategy of the aperture surface, aligns the splicing interface radial surface with the incoming wave, and adjusts the expansion degree of the splicing interface radial surface according to the required scattering characteristics in a complex electromagnetic environment, thereby achieving the purpose of RCS regulation.

[0066] In addition to realizing the RCS adjustable operation, the present invention selects lightweight and high structural strength materials according to the characteristics of structure and material. The upper chord rod 1 and the support rod 2 are both made of carbon fiber hollow rods, the joint hinge structure is made of magnesium aluminum alloy, and the reflective surface is made of a metal mesh made of stainless steel wire. In addition to the advantage of light weight, the metal mesh has the unique softness, high elasticity and high elongation rate, which can still ensure a good reflection effect during the unfolding and folding operation of the present invention. At the same time, the folding characteristics of the present invention can reflect a great volume advantage in terms of transportation and carrying.

Claims

1. An expandable and retractable RCS adjustable reflector, characterized in that: The invention comprises a layer of reflector components and another layer of reflector components arranged in a mirror image, each reflector component comprises n reflector units connected to each other, where n is a positive integer greater than or equal to 6; Each reflector unit is a triangular three-sided corner reflector, each of the reflector units has an aperture surface with an open top and a side surface equipped with a metal wire mesh, the three endpoints of each aperture surface are boundary vertices (3), the vertex of each reflector unit is a support point (4), adjacent boundary vertices (3) are hinged by two upper chord rods (1), adjacent boundary vertices (3) and support points (4) are connected by a support rod (2), and the two upper chord rods (1) are connected by a folding joint (5) to form a foldable structure; The connection form of the n reflector units is: six reflector units are spliced ​​to form a regular hexagonal splicing interface diameter surface with the same aperture opening direction; or, with the regular hexagonal splicing interface diameter surface as the center, the remaining reflector units are sequentially and alternately connected at each boundary vertex (3) outside the central regular hexagon, until the splicing interface diameter surface forms a regular polygon; The two layers of reflector components are hinged correspondingly through n supporting points (4) of each layer to form a movable structure; Each layer of reflector assembly is provided with an expansion-folding mechanism, which is used to expand or fold the expandable-foldable RCS adjustable reflector as a whole about an expansion-folding axis. The expansion-folding axis is a line passing through the centers of the two joint diameter surfaces, and the RCS is controlled by different expansion degrees of the joint diameter surfaces.

2. The expandable and retractable RCS adjustable reflector according to claim 1, characterized in that: The unfolding-folding mechanism on each layer of reflector assembly comprises: A plurality of roller joints (10) are located at each of the boundary vertices (3) of the outermost circle of the joint diameter surface, and include a roller structure and a movable sleeve structure; wherein the roller structure includes a U-shaped roller support (7), and a pin shaft (9) and a roller (8) are arranged in parallel and at intervals at the opening of the roller support (7), and a threading gap is left between the pin shaft (9) and the roller (8); the movable sleeve structure has a plurality of sleeves for being respectively hinged to the upper chord rod (1) and the support rod (2); A thin metal rope (6), one end of which is fixed to any one of the roller supports (7), and the other end of which passes through the threading gaps of the roller supports (7) in sequence and is finally led out from the threading gaps in the roller supports (7) to which the thin metal rope (6) is fixed; A stepping motor is connected to the lead-out end of the thin metal rope (6) and is used to drag the thin metal rope (6) through its external force so as to shrink the diameter surface of the splicing joint.

3. The expandable and retractable RCS adjustable reflector according to claim 1 or 2, characterized in that: The size ratio of the upper chord (1) and the support rod (2) is 1:1.

477. In a fully deployed state, the angle between adjacent upper chords (1) and support rods (2) is 45°, and the angle between every two support rods (2) is 90°.

4. The expandable and retractable RCS adjustable reflector according to claim 3, characterized in that: The connection points between adjacent upper chord rods (1) and upper chord rods (1), the connection points between adjacent upper chord rods (1) and support rods (2), and the connection points between adjacent support rods (2) and support rods (2) are hinged via a joint structure made of an aluminum-magnesium alloy material.

5. The expandable and retractable RCS adjustable reflector according to claim 3, characterized in that: When n=6, the boundary vertices (3) of the six reflector units are connected to each other, and the six aperture surfaces are spliced ​​into a regular hexagon with the same opening direction.

6. The expandable and retractable RCS adjustable reflector according to claim 3, characterized in that: The upper chord rod (1) and the support rod (2) are hollow carbon fiber rods.

7. The expandable and retractable RCS adjustable reflector according to claim 3, characterized in that: The metal wire mesh is gold-plated molybdenum wire, gold-plated iron wire or stainless steel wire, the wire diameter of the metal wire mesh is 0.02mm-0.5mm, and the mesh diameter is 3mm-10mm.

8. A control method for an expandable and retractable RCS adjustable reflector, characterized in that: Based on the expandable and retractable RCS adjustable reflector according to any one of claims 1 to 7, the control method comprises the following contents: Folding process: the thin metal rope (6) is stretched by a driving motor so that the thin metal rope (6) passing through the roller joint (10) is tightened, and each reflector unit is folded around the expansion-folding axis, and the metal wire mesh is also folded accordingly, and the reflector aperture surface is reduced; Unfolding process: the driving motor does not apply external force to the thin metal rope (6), and each reflector unit unfolds under the reaction of the folding joint (5), and the metal wire mesh also unfolds to form a reflecting surface, and the reflector aperture increases; The stretching degree of the thin metal rope is controlled by driving the motor to control the expansion and contraction degree of the splicing interface diameter surface, so that the splicing interface diameter surface can be expanded and contracted to different degrees, and correspondingly different RCSs can be obtained. The RCS can be controlled according to the corresponding relationship between the splicing interface diameter surface and RCS.

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