Method and application of airborne passive radar cross section change

Abstract

The application discloses an airborne passive radar scattering cross-section changing method and application. Under the driving of an ultrasonic motor, a dihedral angle reflector and a trihedral angle reflector composed of a plurality of iron sheets can realize accurate angle change. Meanwhile, based on a special mechanical structure design, the angle of each dihedral angle reflector and the angle of each trihedral angle reflector are equal respectively during the angle change process. The device has good aerodynamic performance and reduces the influence on the flight state of an aircraft. The application can accurately and selectively increase the radar scattering cross-section, so that a small or medium-sized aircraft has the ability to simulate a large aircraft to some extent, and can deceive the radar of an enemy, which is an important supplement to the current active simulation mode.

Description

TECHNICAL FIELD

[0001] The application relates to an airborne radar scattering cross section changing method, in particular to an airborne passive radar scattering cross section changing method capable of realizing accurate control. BACKGROUND

[0002] In modern radar countermeasures, the electromagnetic field scattering characteristics of a target are extremely important. The radar cross section (RCS) is a physical quantity representing the intensity of a return wave generated by a target under radar wave irradiation, and the RCSs of different warplanes are generally different. By changing the RCS of an airplane, different targets can be simulated in a radar, so that the role of a target airplane can be realized in a drill, and the target airplane can be used as a decoy airplane in a war to consume the number of enemy ammunition and divert the attention of an enemy air defense system.

[0003] Therefore, a new RCS changing scheme is urgently needed to simulate different airplane models. Existing RCS changing methods are divided into active and passive methods. The active method suppresses or deceives the interference of an enemy electronic device by intentionally transmitting or retransmiting a certain type of electromagnetic wave, but the system is complex, expensive and energy-consuming. The traditional passive scheme has problems such as too large RCS increment and uncontrollable increment, and cannot meet the needs of simulating specific airplane models.

[0004] The ultrasonic motor has accurate positioning, an angular displacement resolution of 0.375 urad, stable motion speed, low speed of 10 um / s, high speed of 250 mm / s, standard response time of 50-75 us, and setting time obviously better than that of a general servo motor. Taking a resolution of 0.1 um as an example, only 1-2 ms are needed, which is 1 / 10 of that of a general servo motor, and there is no shaking problem existing in the general servo motor after positioning. In addition, the ultrasonic motor has the characteristics of light weight, small size, unlimited travel, large torque at low speed, fast response, good control characteristics, and no electromagnetic interference. The ultrasonic motor is used in the RCS changing device, the characteristics of accurate control of the ultrasonic motor are used to realize accurate motion of the mechanical structure, so that the RCS is accurately changed; and the characteristics of accurate positioning and non-shaking of the ultrasonic motor can realize the maintenance of the RCS and reduce errors.

[0005] Owing to the above advantages, the ultrasonic motor is widely used in the control of aerospace machinery, but there is no scheme for using the ultrasonic motor to control the radar scattering cross section. In view of the problem that the RCS is difficult to accurately control, the application provides a new passive RCS changing design scheme, which uses an ultrasonic motor to drive to accurately control, can realize continuous change of the RCS in a large range, and reach a set value. Meanwhile, the shell design has good aerodynamic performance and is suitable for airborne use. SUMMARY

[0006] In view of the above technical problems, the present application aims to provide a piezoelectric-driven airborne passive radar cross section changing device to solve the problem that the current radar cross section simulation is mainly active and lacks passive radar cross section changing devices, and to realize accurate increase of the radar cross section of small and medium-sized aircrafts to simulate other aircrafts.

[0007] The technical scheme of the present application is as follows:

[0008] The present application provides an airborne passive radar cross section changing method based on an ultrasonic motor, which is realized based on the following device:

[0009] The device comprises hinged steel sheets (2), a rotary ultrasonic motor (3), a plurality of shaft-rotating steel sheets, and a gear set, wherein the output end of the rotary ultrasonic motor (3) is connected to the middle part of the gear set, the gear set is distributed in an axial direction, and a direction-changing gear is connected to the tail part of the gear set; a plurality of shaft-rotating steel sheets are arranged coaxially outside the gear set, and a hinged steel sheet is connected between a group of adjacent shaft-rotating steel sheets.

[0010] The method comprises the following steps:

[0011] The method drives the gear set to rotate through the rotary ultrasonic motor 3, thereby driving the shaft-rotating steel sheets to rotate, changing the included angle between the shaft-rotating steel sheets, and changing the radar cross section.

[0012] Further, the method comprises the following steps:

[0013] The rotary ultrasonic motor 3 drives the two bevel gears to rotate in opposite directions, thereby driving the two connecting rods to rotate in opposite directions; the number of teeth of the inner gear 8 and the outer gear 10 is 1:3, the rotation speed ratio of the front connecting rod 12 and the inner gear 8 is 3:1 according to the transmission ratio of the inner gear 8 and the outer gear 10, which is the inverse of the ratio of the number of teeth of the outer gear 10 to the number of teeth of the inner gear 8, and the rotation speed ratio of the connecting rod 1213 and the outer gear 10 is also 3:1.

[0014] The entire device presents a symmetrical motion state, i.e., the first shaft-rotating steel sheet 4 and the third shaft-rotating steel sheet 6 move in the same direction at a set ratio, and the second shaft-rotating steel sheet 5 and the fourth shaft-rotating steel sheet also move in the same direction at the set ratio, so that the angles of the steel sheets are always equal during the motion from complete overlap to complete unfolding, the connected hinged steel sheet 2 is unfolded during the unfolding of the adjacent two shaft-rotating steel sheets, and the radar cross sections in all directions are consistent.

[0015] The present application also provides an application of an airborne passive radar cross section changing device based on an ultrasonic motor, and the process of the application comprises the following specific steps:

[0016] Step 1: hang the airborne passive radar cross section changing device based on ultrasonic motor under the wings of the aircraft, all the around-the-axis rotating steel sheets are in the initial position of folding down, at this time the radar cross section is minimum;

[0017] Step 2: the aircraft carrying the device takes off, the relationship between the radar cross section of the device and the opening angle is calculated, and the around-the-axis rotating steel sheets are made to present different included angles by controlling the rotating angle of the rotary ultrasonic motor 3 to achieve the predetermined radar cross section.

[0018] The beneficial effects of the present application are:

[0019] In view of the current situation that the airborne passive analog radar cross section device is lacking, the present application proposes a reasonable scheme to fill the related vacancy. The present application adopts ultrasonic motor driving, has the characteristics of light weight, small size, unlimited travel, low speed and large torque, fast speed, good control characteristics, no electromagnetic interference, etc. The problem of low precision and inaccurate control of the rotating angle in the traditional control mode is solved, and after the relationship between the rotating angle and the radar cross section of the device is calculated, the predetermined radar cross section can be simulated by controlling the ultrasonic motor. At the same time, through design, the angles of the three quasi-biangular reflectors and the three quasi-triangular reflectors composed of the device are always equal during the change process, which ensures that the radar scattering characteristics in each direction are basically the same. And through the wrapping of the shell, the whole device has good aerodynamic performance, which is suitable for aircraft mounting to perform tasks. The present application can effectively realize the simulation of the predetermined radar cross section under passive condition, and provides a new method for airborne target simulation and enemy interference.

[0020] The present application utilizes the precise driving characteristics of the ultrasonic motor, and through the design of a special transmission device, the accurate change of the radar cross section under passive condition is realized. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is the overall schematic diagram of the device of the present application;

[0022] Figure 2 is the internal core structure schematic diagram of the device of the present application;

[0023] Figure 3 is the rear isometric schematic diagram of the internal core structure of the device of the present application. DETAILED DESCRIPTION

[0024] The application will be further described below in connection with the drawings and specific embodiments. It should be noted that the following embodiments are only used to illustrate certain implementation examples of the method and do not limit the protection scope of the application. Any modification or change made by the person skilled in the art based on the radar scattering cross-section changing device in the application after the application is disclosed belongs to the protection scope defined in the claims of the application.

[0025] A design scheme of airborne passive changing of RCS features based on an ultrasonic motor is an important supplement to the current common active changing of RCS features. The ultrasonic motor has the characteristics of low speed, large torque, no need of gear reduction mechanism, small rotor inertia and fast response, and can realize accurate control of the corner reflector. Through the design of the mechanical structure, the corner reflector is used to achieve the purpose of variable radar scattering cross-section.

[0026] Embodiment 1

[0027] The application is an airborne passive radar scattering cross-section changing device based on an ultrasonic motor. The device comprises hinged steel sheets 2, a rotary ultrasonic motor 3, a plurality of shaft rotating steel sheets and a gear set. The output end of the rotary ultrasonic motor 3 is connected to the middle part of the gear set. The gear set is distributed in the axial direction. A direction changing gear is connected to the tail part of the gear set. A plurality of shaft rotating steel sheets are arranged coaxially outside the gear set. A hinged steel sheet is connected between a group of adjacent shaft rotating steel sheets.

[0028] Further, the plurality of shaft rotating steel sheets comprise a first shaft rotating steel sheet 4, a second shaft rotating steel sheet 5, a third shaft rotating steel sheet 6 and a fourth shaft rotating steel sheet 7. The four shaft rotating steel sheets are distributed at equal angles outside the gear set.

[0029] Further, the device comprises three groups of hinged steel sheets 2. The hinged steel sheet 2 is hinged by two triangular steel sheets. The three groups of hinged steel sheets 2 are located on the front side of the device. The two ends of the first group of hinged steel sheets are fixedly connected to the first shaft rotating steel sheet 4 and the third shaft rotating steel sheet 6. The two ends of the second group of hinged steel sheets are fixedly connected to the third shaft rotating steel sheet 6 and the fourth shaft rotating steel sheet 7. The two ends of the third group of hinged steel sheets are fixedly connected to the second shaft rotating steel sheet 5 and the fourth shaft rotating steel sheet 7. The hinged steel sheet moves with the movement of the shaft rotating steel sheet.

[0030] Further, the gear set comprises an internal gear 8, a bevel gear 9, an external gear 10, a change direction gear 11, a front side connecting rod 12, and a rear side connecting rod 13; the device comprises two symmetrically arranged bevel gears, the conical surfaces of the two bevel gears are opposite; the device comprises two internal gears and two external gears, wherein the output end of the rotary ultrasonic motor 3 is connected to the middle of the two bevel gears, the rotary ultrasonic motor 3 drives the two bevel gears to rotate, and on the outer side of the two bevel gears, the internal gear and the external gear are arranged in sequence; each gear is mounted on the front side connecting rod 12 and the rear side connecting rod 13.

[0031] The first rotation around the axis steel sheet 4 is fixed to the rear side connecting rod 13, the second rotation around the axis steel sheet 5 is fixed to the front side connecting rod 12, the third rotation around the axis steel sheet 6 is fixed to the front side internal gear, and the fourth rotation around the axis steel sheet 7 is fixed to the rear side internal gear.

[0032] As a preferred embodiment of the present application, the device is further provided with a shell 1, which is arranged outside the whole device and wraps the rotation around the axis steel sheets; all the change direction gears 11 are fixed in space position by the fixed shafts leading to the inside of the shell 1, so that they can only rotate around the center.

[0033] As a preferred embodiment of the present application, the gear ratio of the external gear 10 and the internal gear 8 is 1:3.

[0034] Referring to Figure 1 , 2,3, through the FEKO software calculation, the radar scattering cross section area changes with the angle change of the three groups of hinged steel sheet 2, the first around the shaft rotating steel sheet 4, the second around the shaft rotating steel sheet 5, the third around the shaft rotating steel sheet 6, the fourth around the shaft rotating steel sheet 7, through the precise control of the rotating ultrasonic motor 3, the RCS can be realized in a large range continuously change, reach the predetermined reflection cross section area. As shown, the rotating ultrasonic motor 3 drives two bevel gears 9, ensures that the two groups of opposite motion, on two connecting rods are respectively installed two external gear 10 two direction gear 11, plus two external gear 10, in the case of ensuring the external gear 10 and the internal gear 8 on the rod tooth number ratio is 1:3, can be calculated the speed ratio of the rod and the internal gear is 3:1, need to pay attention, four around the shaft rotating steel sheet shape and connection mode exist difference, the first around the shaft rotating steel sheet 4 is connected with the rear connecting rod 13, the second around the shaft rotating steel sheet 5 is connected with the front connecting rod 12, the third around the shaft rotating steel sheet 6 is connected with the front internal gear 8, the fourth around the shaft rotating steel sheet 7 is connected with the rear internal gear 8, through such design, makes the several iron sheet in from the most below to such completely spread out the movement process, each angle is always equal, the lower steel sheet rotating stroke is 0-45 DEG, the upper iron sheet rotating stroke is 0-135 DEG, ensure that the radar scattering cross section area in each direction is basically the same; At the same time, the front six iron sheet is hinged two by two to form three three-sided angle reflectors, which increases the RCS changing performance of the front, and there is no dead point position when fully expanded, which is convenient for folding and unfolding. Under the wrapping of the shell, the device has good aerodynamic performance and can be used for aircraft carrying.

[0035] Example 2:

[0036] Based on the above device, the application also provides an airborne passive radar scattering cross section changing method based on ultrasonic motor, which comprises the following steps:

[0037] The method drives the gear set to rotate through the rotating ultrasonic motor 3, thereby driving the around-the-shaft rotating steel sheet to rotate, so that the included angle between the around-the-shaft rotating steel sheets changes, thereby changing the radar scattering cross section.

[0038] Further, the method comprises the following steps:

[0039] The rotating ultrasonic motor 3 drives the two bevel gears to rotate in opposite directions, thereby driving the two connecting rods to rotate in opposite directions; the internal gear 8 and the external gear 10 have a tooth number ratio of 1:3, and according to the transmission ratio of the internal gear 8 and the external gear 10 being equal to the inverse of the ratio of the tooth number of the external gear 10 to the tooth number of the internal gear 8, the speed ratio of the front connecting rod 12 and the internal gear 8 is calculated to be 3:1, and then the speed ratio of the connecting rod 1213 and the external gear 10 is also 3:1;

[0040] The entire device presents a symmetrical motion state, that is, the first rotating steel sheet 4 and the third rotating steel sheet 6 move in the same direction at a set ratio, and the second rotating steel sheet 5 and the fourth rotating steel sheet also move in the same direction at the set ratio, so that the angles of the steel sheets are always equal in the process of unfolding from complete overlap, and the adjacent rotating steel sheets drive the connected hinged steel sheet 2 to unfold in the unfolding process, thereby ensuring that the radar scattering cross-sectional area in each direction is consistent.

[0041] The front end of the rotary ultrasonic motor 3 is provided with a bevel gear, which is engaged with two same bevel gears on the front connecting rod 12 and the rear connecting rod 13, drives the two bevel gears to rotate in opposite directions, and drives the two connecting rods to rotate in opposite directions; two outer meshing gears 10 are additionally provided on the two connecting rods, and are engaged with two variable direction gear idlers 11; the variable direction gear idlers 11 are fixed at a space-determined position by the shaft led out from the inside of the shell, and can only rotate around the center; in the transmission process, the variable direction gear does not change the gear transmission ratio, but only changes the rotation direction of the gear; the variable direction gear is additionally engaged with two inner and outer meshing gears 810; under the condition that the tooth number ratio of the outer meshing gear 10 on the rod and the inner meshing gear 8 is 1:3, the variable direction gear idler does not change the transmission ratio, and the speed ratio of the connecting rod and the inner meshing gear can be calculated as 3:1; it should be noted that the shapes and connection modes of the four rotating steel sheets are different; the first rotating steel sheet 4 is connected with the rear connecting rod 13, the second rotating steel sheet 5 is connected with the front connecting rod 12, the third rotating steel sheet 6 is connected with the front inner meshing gear 8, and the fourth rotating steel sheet 7 is connected with the rear inner meshing gear 8; through such a design, the first rotating steel sheet 4 and the third rotating steel sheet 6 move in the same direction, and the speed ratio is 3:1, so the stroke ratio is also 3:1; the second rotating steel sheet 5 and the fourth rotating steel sheet move in the same direction, and the speed ratio is 3:1, so the stroke ratio is also 3:1; in the process of folding from the most lower end to unfolding of the four rotating steel sheets, the entire device presents a symmetrical motion state, and the rotation of the front connecting rod 12, the rear connecting rod 13 and the inner meshing gear 8 is output for the motion of the four rotating steel sheets; since the angle stroke ratio of the connecting rod and the inner meshing gear is always 3:1, and the motion directions of the left and right sides are opposite, the three angles below the four rotating steel sheets make the angles always equal in the process of folding from the most lower end to unfolding, and the adjacent rotating steel sheets drive the connected hinged steel sheet 2 to unfold in the unfolding process, thereby ensuring that the radar scattering cross-sectional area in each direction is basically consistent.

[0042] Example 3:

[0043] The application also provides an application of the airborne passive radar scattering cross-sectional area changing device based on an ultrasonic motor, and the process of the application includes the following specific steps.

[0044] Step 1: before the aircraft takes off, the device is hung under the aircraft wing, all the iron sheets are in the initial position of folding down, at this time the radar cross section is minimum;

[0045] Step 2: the aircraft takes off with the device, according to the relationship between the radar cross section of the device and the opening angle calculated, the iron sheets are made to present different included angles by controlling the rotation angle of the ultrasonic motor to achieve the predetermined radar cross section according to the task requirement.

[0046] The above describes the embodiments of the present application in combination with the drawings, but the present application is not limited to the above embodiments, and can be changed in various ways according to the purpose of the present application, any change, modification, replacement, combination or simplification made according to the spirit and principle of the technical solution of the present application shall be an equivalent replacement, as long as it meets the purpose of the present application, as long as it does not deviate from the technical principle and inventive concept of the present application, it belongs to the protection scope of the present application.

Claims

1. An airborne passive radar cross section changing method based on an ultrasonic motor, characterized in that, The method is realized based on the device: The device comprises articulated steel sheets (2), a rotary ultrasonic motor (3), a plurality of axis rotating steel sheets, and a gear set, wherein the output end of the rotary ultrasonic motor (3) is connected to the middle of the gear set, the gear set is distributed in an axial direction, and a direction-changing gear is connected to the tail of the gear set; a plurality of axis rotating steel sheets are coaxially arranged outside the gear set, and articulated steel sheets are connected between three adjacent axis rotating steel sheets. The method comprises the following steps: The method drives the gear set to rotate by the rotary ultrasonic motor (3), thereby driving the axis rotating steel sheets to rotate, changing the included angle between the axis rotating steel sheets, and changing the radar scattering cross section. The method comprises the following steps: The rotary ultrasonic motor (3) drives the two bevel gears to rotate in opposite directions, thereby driving the two connecting rods to rotate in opposite directions; the number of teeth of the outer meshing gear (10) and the inner meshing gear (8) is 1:3, the transmission ratio of the inner meshing gear (8) and the outer meshing gear (10) is equal to the inverse of the ratio of the number of teeth of the outer meshing gear (10) to the number of teeth of the inner meshing gear (8), the rotation speed ratio of the front connecting rod (12) and the inner meshing gear (8) is 3:1, and the rotation speed ratio of the connecting rod (12) (13) and the outer meshing gear (10) is also 3:1; The entire device presents a symmetrical motion state, i.e., the first axis rotating steel sheet (4) and the third axis rotating steel sheet (6) move in the same direction at a set ratio, and the second axis rotating steel sheet (5) and the fourth axis rotating steel sheet also move in the same direction at the set ratio, so that the angles of the steel sheets are always equal during the motion from complete overlap to complete unfolding, and the articulated steel sheet (2) connected between the two adjacent axis rotating steel sheets is unfolded during the unfolding process, thereby ensuring that the radar scattering cross sections in all directions are consistent.

2. The method of claim 1, wherein the ultrasonic motor is a piezoelectric motor. The plurality of axis rotating steel sheets comprise a first axis rotating steel sheet (4), a second axis rotating steel sheet (5), a third axis rotating steel sheet (6), and a fourth axis rotating steel sheet (7), and the four axis rotating steel sheets are distributed at equal angles outside the gear set.

3. The method of claim 1, wherein the ultrasonic motor is a piezoelectric motor. The device comprises three sets of articulated steel sheets (2), each of which is formed by articulating two triangular steel sheets, and the three sets of articulated steel sheets (2) are located on the front side of the device, the two ends of the first set of articulated steel sheets are fixedly connected to the first axis rotating steel sheet (4) and the third axis rotating steel sheet (6), the two ends of the second set of articulated steel sheets are fixedly connected to the third axis rotating steel sheet (6) and the fourth axis rotating steel sheet (7), the two ends of the third set of articulated steel sheets are fixedly connected to the second axis rotating steel sheet (5) and the fourth axis rotating steel sheet (7), and the articulated steel sheets move with the axis rotating steel sheets.

4. The method of claim 1, wherein the ultrasonic motor is a piezoelectric motor. The gear set comprises an internal gear (8), a bevel gear (9), an external gear (10), a direction-changing gear (11), a front-side connecting rod (12), and a rear-side connecting rod (13); the device comprises two symmetrically arranged bevel gears, the conical surfaces of the two bevel gears being opposite to each other; the device comprises two internal gears and two external gears, wherein the output end of the rotary ultrasonic motor (3) is connected to the middle of the two bevel gears (9), the rotary ultrasonic motor (3) is used to drive the two bevel gears to rotate, and on the outer sides of the two bevel gears, the internal gears and the external gears are arranged in sequence; each gear is mounted on the front-side connecting rod (12) and the rear-side connecting rod (13). The first rotation-axle steel sheet (4) is fixed to the rear-side connecting rod (13), the second rotation-axle steel sheet (5) is fixed to the front-side connecting rod (12), the third rotation-axle steel sheet (6) is fixed to the front-side internal gear, and the fourth rotation-axle steel sheet (7) is fixed to the rear-side internal gear.

5. The method of claim 1 to 4, wherein the method is based on an ultrasonic motor onboard passive radar cross section changing method. The device is further provided with a shell (1) arranged outside the entire device and wrapping the rotation-axle steel sheets; all the direction-changing gears (11) are fixed in space position by fixed shafts led into the shell (1) and can only rotate around the center.

6. An application of an airborne passive radar cross section changing device based on an ultrasonic motor, characterized in that, The application process comprises the following specific steps: Step 1: hang the airborne passive radar cross section changing device based on the ultrasonic motor under the wings of an aircraft, all the rotation-axle steel sheets are in the initial position of being folded downwards, and the radar cross section is minimum at this time; Step 2: the aircraft carrying the device takes off, the relationship between the radar cross section of the device and the opening angle is calculated, and the rotation angle of the rotary ultrasonic motor (3) is controlled to make the rotation-axle steel sheets present different included angles to achieve the predetermined radar cross section.

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