A method for designing a missile-borne radar forward-looking imaging guidance system

Abstract

The application provides a missile-borne radar front-oblique imaging guidance system design method, which comprises the following steps: determining the range resolution and azimuth resolution requirements of a small short-range tactical missile radar seeker that meets the identification requirements according to the combat scene of a short-range missile and the target type of an attack; based on the frame angle constraint of the radar seeker, establishing the radar guidance geometry and the radar imaging mode of the small short-range tactical missile, constructing the relationship between the synthetic aperture rotation angle accumulation and the central oblique angle, and then designing the flight path, the time length and other parameters of the missile to form the imaging guidance system of the small short-range tactical missile. The method can improve the target detection and identification capability of the small tactical missile and provides a method and technical support for the design of the imaging guidance system of the radar-guided small tactical missile.

Description

Technical Field

[0001] The present invention relates to the field of small short-range tactical missile guidance system design, and in particular to a missile-borne radar forward oblique imaging guidance system design method. Background Art

[0002] In the system design of small, short-range tactical missiles, the ballistic trajectory is often designed to maintain a nearly straight trajectory, which helps improve the missile's flight speed and penetration capability while reducing energy loss during flight. In this trajectory mode, the missile's flight path typically does not involve significant curvature. Unlike optoelectronic guidance systems, radar-guided missiles fly directly toward their targets. This means that the radar seeker can only detect and identify targets using a one-dimensional range profile. While this can capture target characteristics such as structure and size, the target information obtained is still limited compared to a two-dimensional image. On the one hand, the one-dimensional range profile lacks detailed information about the target in the horizontal direction, which can make it difficult for the missile to discern the target's true shape and size during attack, thus affecting strike accuracy. On the other hand, the one-dimensional range profile has weak target recognition capabilities, especially in complex battlefield environments, and is easily affected by noise and interference, resulting in a high risk of misidentification during missile missions.

[0003] Two-dimensional imaging can capture more dimensional information about a target, extracting richer target features for a more precise description of its characteristics. Once a short-range tactical missile has locked onto a detected target, the target remains within the missile seeker's field of view. To achieve higher resolution, a spotlight mode is used for imaging processing. Therefore, designing a two-dimensional imaging guidance system for short-range tactical missiles to improve their target detection and recognition capabilities is of great significance to the field of radar-guided homing systems for small, short-range tactical missiles. Summary of the Invention

[0004] The purpose of the present invention is to provide a design method for a missile-borne radar forward oblique imaging guidance system, which is used to plan the ballistic path of a tactical missile and improve the target recognition performance of radar-guided short-range tactical missiles in complex scenarios.

[0005] In order to achieve the above tasks, the present invention adopts the following technical solutions:

[0006] A design method for a missile-borne radar forward oblique imaging guidance system, comprising:

[0007] Step 1: Determine the technical parameters required for tactical missile radar guidance based on the combat scenario, target type, and target recognition probability requirements;

[0008] Step 2: Utilizing the radar seeker detection capability in the technical parameters, combined with the missile altitude and the target position measured by the fire control radar, the tactical missile initial position, initial missile-target range, initial yaw angle, initial pitch angle, and downward viewing angle are calculated based on the large forward squint initial squint angle; wherein the large forward squint initial squint angle satisfies the large forward squint angle constraint in the technical parameters;

[0009] Step 3: Determine the range signal transmission bandwidth based on the range imaging resolution requirements of the radar seeker in the technical parameters and the downward viewing angle;

[0010] Step 4: Based on the requirements for the radar seeker's azimuth imaging resolution in the technical parameters, combined with the initial squint angle, the wavelength of the transmitted signal, and the velocity of the missile-carrying platform, determine the relationship between the synthetic aperture center squint angle and the synthetic aperture angle accumulation as the first equation;

[0011] Step 5: Based on the scene geometry requirements of the radar seeker's large forward squint system, combined with the initial squint angle and the initial missile-target distance, the relationship between the synthetic aperture center squint angle and the synthetic aperture angle accumulation is determined as the second equation;

[0012] Step 6: Solve the first and second equations together using the Newton-Raphson method to obtain the central squint angle of the synthetic aperture and the accumulation of the synthetic aperture angle.

[0013] Step 7: Determine the synthetic aperture time and synthetic aperture length required to achieve the required resolution based on the accumulated synthetic aperture central squint angle and synthetic aperture rotation angle, which serve as the imaging guidance flight time and flight distance of the short-range missile at the final moment.

[0014] Step 8: Calculate the pitch angle and yaw angle at the end of the synthetic aperture imaging guidance according to the radar field of view angle, and determine whether the pitch angle and yaw angle at the end of the synthetic aperture imaging guidance are within the frame angle range specified in the technical parameters; calculate the missile-target distance, and determine whether the missile-target distance at the end of the synthetic aperture imaging guidance is within the radar imaging guidance strike range;

[0015] If the pitch angle and yaw angle are both within the frame angle range, and the missile-target distance is within the radar imaging guidance strike range, then the guidance system design is successful; otherwise, return to step 2 and redesign.

[0016] Furthermore, the technical parameters that need to be met by the tactical missile radar guidance include:

[0017] Range resolution ρ of radar seeker r and azimuth resolution ρ a , radar seeker detection capability Radar seeker frame angle range, including the maximum limit of the pitch frame angle φ maxand the maximum limit of the yaw frame angle ψ max , radar imaging guidance strike range, including minimum strike range and maximum striking distance Radar seeker 3dB beamwidth β 3dB , the constraints of the squint angle in the large front squint scene, including the minimum squint angle under large front squint and the maximum anterior strabismus angle under large anterior strabismus

[0018] Furthermore, the method of calculating the initial position, initial missile-target distance, initial yaw angle, initial pitch angle and downward viewing angle of the tactical missile based on the large forward squint initial squint angle includes:

[0019] Initial position of short-range tactical missile (x m ,y m ,H) is based on the target position (x t ,y t ,z t ) is the dot, the initial projectile-target distance R s The initial target distance R is on the circle with radius s Should be less than or equal to the radar seeker detection capability And the oblique angle with the target position is Calculate the missile initial position (x m ,y m ,H) is:

[0020]

[0021] Seeker initial yaw angle φ s is the angle between the projection of the target azimuth vector on the horizontal plane and the positive x-axis; calculate the initial yaw angle φ of the seeker s for:

[0022]

[0023] Determine the initial yaw angle φ of the seeker s , must be less than or equal to the radar seeker field of view limit;

[0024] Initial pitch angle ψ s is the angle between the projection of the target azimuth vector on the horizontal plane and the positive x-axis; calculate the initial pitch angle ψ s for:

[0025]

[0026] Determine the initial pitch angle ψ of the seeker s , must be less than or equal to the radar seeker field of view Limit, where β 3dB is the 3dB beam width of the radar seeker, ψ max is the maximum limit of the yaw frame angle;

[0027] The seeker uses a large forward squint initial squint angle θ s and the initial yaw angle φ of the seeker s and the initial pitch angle of the seeker ψ s The relationship is:

[0028] θ s =arcsin(cosφ s ·cosψ s ) (4)

[0029] The lower viewing angle α is the angle between the minimum slant range R0 and the self-height of the radar seeker M. The lower viewing angle α is calculated as:

[0030]

[0031] Furthermore, the distance-to-signal transmission bandwidth is determined as:

[0032]

[0033] Where c is the speed of light, ρ r is the imaging resolution in the range direction, and α is the downward viewing angle.

[0034] Furthermore, the construction process of the first equation is:

[0035] The forward oblique imaging guidance system is in the synthetic aperture time range (t s ,t e ) observes the imaging area, and the synthetic aperture time is T s =t e -t s , where t s ,t e are the initial and final moments respectively; the moment at the center of the synthetic aperture is t c ; For the scene center point target, at the initial synthetic aperture time t s , the initial oblique angle is θ s , then the instantaneous Doppler frequency at the initial moment is:

[0036]

[0037] At the end of the synthetic aperture t e , the oblique angle is θ e , then the instantaneous Doppler frequency at the last moment is:

[0038]

[0039] Then, during the entire observation time, the Doppler bandwidth of the echo signal at the center of the scene is:

[0040]

[0041] The azimuth resolution can be calculated as:

[0042]

[0043] Solve equation (10) to get θ c ,Right now:

[0044]

[0045] From this, we can establish the first equation θ c =f1(θ syn ).

[0046] Furthermore, the construction process of the second equation is:

[0047] Initial target distance R s The projected length in the direction of motion of the missile-carrying platform is R s sinθ s , the distance between the projectile and the target at the last moment is R e The projected length in the direction of motion of the missile-carrying platform is R s cosθ s tan(θ s -θ syn ), the distance between the projectile and the target at the center of the synthetic aperture R c The projected length in the direction of motion of the missile-carrying platform is R0tanθ c , then:

[0048] R s sinθ s -R s cosθ s tan(θ s -θ syn )=2R s sinθ s -2R s cosθ s tanθ c (12)

[0049] Simplified:

[0050] -cosθ s tan(θ s -θ syn )=sinθ s -2cosθ s tanθ c(13)

[0051] Solve equation (13) to get θ c ,Right now:

[0052]

[0053] This allows us to establish the second equation θ c =f2(θ syn ).

[0054] Furthermore, the first equation and the second equation are solved by the Newton-Raphson method to obtain the central squint angle of the synthetic aperture and the accumulation of the synthetic aperture rotation angle, including:

[0055] First, θ c =f1(θ syn ) is rewritten as F1(θ c ,θ syn )=0, and θ c =f2(θ syn ) is rewritten as F2(θ c ,θ syn )=0, the system of equations can be obtained as follows:

[0056]

[0057] Next, suppose the solution of the equation x=[θ c ,θ syn ] T , the superscript T represents the transpose; the vector function F(x), Jacobian matrix J(x) and Newton iteration formula are defined as follows:

[0058] The vector function F(x) is:

[0059]

[0060] The Jacobian matrix J(x) is:

[0061]

[0062] The Newton iteration formula is:

[0063] x n+1 =x n -J(x n ) -1 F(x n ) (18)

[0064] Finally, the Newton-Raphson method is used to solve the equation x = [θ c ,θ syn ] T , get the central slant angle θ of the synthetic aperturec and synthetic aperture angle accumulation θ syn , where x n Represents the x solved at the nth iteration.

[0065] Furthermore, according to the central slant angle θ of the synthetic aperture c and synthetic aperture angle accumulation θ syn , combined with the closest slant distance R0 and the missile-carrying platform motion speed v, the missile imaging guidance flight distance L at the final moment s The calculation of is as follows:

[0066] L s =R0 tan(θ s )-R0 tan(θ s -θ syn ) (20)

[0067] Final missile imaging guidance flight time T s The calculation of is as follows:

[0068]

[0069] Furthermore, the missile-target distance R at the end of synthetic aperture imaging guidance e The calculation is:

[0070]

[0071] Pitch angle φ at the final moment e The calculation is:

[0072]

[0073] Yaw angle ψ at the final moment e The calculation is:

[0074]

[0075] If the pitch angle φ at the end e , yaw angle ψ e The maximum limit of the pitch frame angle is φ max , maximum limit of yaw frame angle ψ max If the distance between the missile and the target at the end is R, then the pitch angle and yaw angle required for the imaging of the radar seeker of the short-range tactical missile meet the range of the seeker's viewing angle. e At minimum striking distance Maximum strike distance Within, tactical missiles can hit the target.

[0076] A terminal device comprises a processor, a memory and a computer program stored in the memory; when the processor executes the computer program, the design method of the missile-borne radar forward oblique imaging guidance system is implemented.

[0077] Compared with the prior art, the present invention has the following technical features:

[0078] The method of the present invention can design a radar forward oblique two-dimensional imaging guidance system for a small short-range tactical missile according to combat scenarios, target types, and target recognition probability requirements. The method can obtain a richer range of targets through two-dimensional imaging, construct trajectory conditions for radar two-dimensional imaging that meets recognition requirements, improve the target detection and recognition capabilities of small tactical missiles, and provide method and technical support for the design of radar-guided imaging guidance systems for small tactical missiles. BRIEF DESCRIPTION OF THE DRAWINGS

[0079] Figure 1 is a flow chart of the method of the present invention;

[0080] Figure 2 Designing an imaging guidance geometry diagram for the present invention;

[0081] Figure 3 This is the ballistic trajectory diagram for a single-target scenario using the method of the present invention;

[0082] Figure 4 This is the imaging result diagram of the method of the present invention in a single target scene;

[0083] Figure 5 The following are the imaging results of the method of the present invention in 5 target scenes;

[0084] Figure 6 The pitch angle and yaw angle variation curves of the target at the missile-borne synthetic aperture distance according to the method of the present invention;

[0085] Figure 7 It is the envelope diagram of the distance and azimuth directions of a single target using the method of the present invention. DETAILED DESCRIPTION

[0086] The basic idea of ​​the present invention is to determine the range and azimuth resolution requirements of a small short-range tactical missile radar seeker that meet identification needs based on the combat scenario of the short-range missile and the type of target being attacked; based on the radar seeker frame angle constraints, establish the small short-range tactical missile radar guidance geometry and radar imaging mode, construct the relationship between synthetic aperture angle accumulation and central oblique angle, and then design the missile flight path, duration and other parameters to form a small short-range tactical missile imaging guidance system.

[0087] See attached Figure 1 The present invention provides a missile-borne radar forward oblique imaging guidance system design method, comprising the following steps:

[0088] Step 1: Determine the technical parameters required for tactical missile radar guidance based on the combat scenario, target type, and target recognition probability requirements. Specifically, these parameters include:

[0089] Range resolution ρ of radar seeker r and azimuth resolution ρ a , and radar seeker detection capabilities Radar seeker frame angle range (i.e. maximum limit of pitch frame angle φ max , the maximum limit of yaw frame angle ψ max ), radar imaging guided strike range (i.e. minimum strike range Maximum strike distance ), radar seeker 3dB beam width β 3dB , the constraint condition of the squinting angle in the large front squint scene (i.e. the minimum squinting angle under large front squint) Maximum protraction angle under large protraction ).

[0090] Step 2: Utilize the radar seeker detection capability in the technical parameters Combined with the missile height H, the target position (x t ,y t ,z t ), according to the initial strabismus angle θ s Find the initial position of the tactical missile (x m ,y m ,H), initial projectile-target distance R s , initial yaw angle φ s , initial pitch angle ψ s , and the lower angle α. Among them, the initial angle of the large front squint θ s Satisfy the large front oblique viewing angle constraint in the technical parameters, namely

[0091] Initial position of short-range tactical missile (x m ,y m ,H) is based on the target position (x t ,y t ,z t ) is the dot, the initial projectile-target distance R s The initial target distance R is on the circle with radius s Should be less than or equal to the radar seeker detection capability And the oblique angle with the target position is Usually the oblique angle is greater than 70°; calculate the missile initial position (x m ,y m,H) is:

[0092]

[0093] The coordinate system established when determining the position sets the x-axis and y-axis in the horizontal plane, and takes the height direction as the z-axis.

[0094] Seeker initial yaw angle φ s It is the angle between the projection of the target azimuth vector on the horizontal plane (i.e., the xy plane) and the positive x-axis; Calculate the initial yaw angle φ of the seeker s for:

[0095]

[0096] Determine the initial yaw angle φ of the seeker s , must be less than or equal to the radar seeker field of view angle limit.

[0097] Initial pitch angle ψ s is the angle between the projection of the target azimuth vector on the horizontal plane and the positive x-axis; calculate the initial pitch angle ψ s for:

[0098]

[0099] Determine the initial pitch angle ψ of the seeker s , must be less than or equal to the radar seeker field of view angle limit

[0100] The seeker uses a large forward squint initial squint angle θ s and the initial yaw angle φ of the seeker s and the initial pitch angle of the seeker ψ s The relationship is:

[0101] θ s =arcsin(cosφ s ·cosψ s ) (4)

[0102] The lower viewing angle α is the angle between the minimum slant range R0 and the self-height of the radar seeker M. The lower viewing angle α is calculated as:

[0103]

[0104] Step 3: According to the range imaging resolution ρ of the radar seeker in the technical parameters r The requirements of the distance signal transmission bandwidth B are determined by combining the viewing angle α. r .

[0105]

[0106] Where c is the speed of light.

[0107] Step 4: According to the radar seeker azimuth imaging resolution ρ in the technical parameters a The requirements, combined with the initial oblique angle θ s The wavelength of the transmitted signal λ and the velocity v of the missile-carrying platform are used to determine the central slant angle θ of the synthetic aperture. c and synthetic aperture angle accumulation θ syn The relationship between θ and θ is the first equation. c =f1(θ syn ). The expression creation process is as follows:

[0108] The Doppler frequency of the echo signal is twice the ratio of the platform radial velocity to the signal wavelength. The forward oblique imaging guidance system is within the synthetic aperture time range (t s ,t e ) observes the imaging area, and the synthetic aperture time is T s =t e -t s , where t s ,t e are the initial and final moments respectively; the moment at the center of the synthetic aperture is t c .

[0109] For the scene center target, at the initial synthetic aperture time t s , the initial oblique angle is θ s , then the instantaneous Doppler frequency at the initial moment is:

[0110]

[0111] At the end of the synthetic aperture t e , the oblique angle is θ e , then the instantaneous Doppler frequency at the last moment is:

[0112]

[0113] Then, during the entire observation time, the Doppler bandwidth of the echo signal at the center of the scene is:

[0114]

[0115] The azimuth resolution can be calculated as:

[0116]

[0117] Solve equation (10) to get θ c ,Right now:

[0118]

[0119] From this, we can establish the first equation θ c =f1(θ syn ).

[0120] Step 5: Based on the requirements of the scene geometry of the radar seeker large forward squint system, the initial squint angle θ is used. s and the initial projectile-target distance R s , determine the central slant angle θ of the synthetic aperture c and synthetic aperture angle accumulation θ syn The relationship between the two equations is θ c =f2(θ syn ). The expression creation process is as follows:

[0121] The starting slant angle θ of the synthetic aperture obtained in step 2 s , initial projectile-target distance R s , the closest slant distance R0 of the projectile and the target, combined with the scene geometry of the large front squint system, can be obtained by the synthetic aperture length L s Establish the equation, synthetic aperture length L s Not only equal to the initial projectile-target distance R s The projected length in the direction of movement of the missile-carrying platform and the distance R between the missile and the target at the final moment e The difference in the projected length in the direction of motion of the missile-carrying platform is also equal to the initial missile-target distance R s The projected length in the direction of motion of the missile-carrying platform and the missile-target distance R at the center of the synthetic aperture c Twice the difference in the projected lengths in the direction of motion of the missile-carrying platform.

[0122] Initial target distance R s The projected length in the direction of motion of the missile-carrying platform is R s sinθ s , the distance between the projectile and the target at the last moment is R e The projected length in the direction of motion of the missile-carrying platform is R s cosθ s tan(θ s -θ syn ), the distance between the projectile and the target at the center of the synthetic aperture R c The projected length in the direction of motion of the missile-carrying platform is R0tanθ c , then:

[0123] R s sinθ s -R s cosθ s tan(θ s -θ syn )=2R s sinθ s -2Rs cosθ s tanθ c (12)

[0124] Simplified:

[0125] -cosθ s tan(θ s -θ syn )=sinθ s -2cosθ s tanθ c (13)

[0126] Solve equation (13) to get θ c ,Right now:

[0127]

[0128] This allows us to establish the second equation θ c =f2(θ syn ).

[0129] Step 6, solve the first equation θ c =f1(θ syn ) and the second equation θ c =f2(θ syn ), and the Newton-Raphson method is used to solve the central slant angle θ of the synthetic aperture. c and synthetic aperture angle accumulation θ syn .

[0130] First, θ c =f1(θ syn ) is rewritten as F1(θ c ,θ syn )=0, and θ c =f2(θ syn ) is rewritten as F2(θ c ,θ syn )=0, the system of equations can be obtained as follows:

[0131]

[0132] Next, suppose the solution of the equation x=[θ c ,θ syn ] T , define the vector function F(x), Jacobian matrix J(x) and Newton iteration formula as follows:

[0133] The vector function F(x) is:

[0134]

[0135] The Jacobian matrix J(x) is:

[0136]

[0137] The Newton iteration formula is:

[0138] x n+1 =x n -J(x n ) -1 F(x n ) (18)

[0139] Finally, the Newton-Raphson method is used to solve the equation x = [θ c ,θ syn ] T , the steps are as follows:

[0140] (1) Select the initial guess value Among them, x0 is the initial value of x, x n is the value of x at the nth iteration;

[0141] (2) Calculate the vector function F(x) under the current estimate n ) and the Jacobian matrix J(x n ).

[0142] (3) Solve the equation system J(x n )Δx n =-F(x n ) Find Δx n .

[0143] (4) Update the estimated value x n , get the next estimated value x n+1 , the iteration formula is: n+1 =x n +Δx n .

[0144] (5) Check whether the convergence condition is met and compare whether the difference between the results of two consecutive iterations is less than the preset tolerance value ε:

[0145] |x n+1 -x n |<ε (19)

[0146] If the difference is less than the preset tolerance value ε, the convergence condition is met.

[0147] (5) If the difference is not less than the preset tolerance value ε, repeat (2) to (5) until the difference is less than the preset tolerance or the maximum number of iterations is reached, that is, the convergence condition is met.

[0148] (6) After the convergence conditions are met, output

[0149] Step 7: Based on the central slant angle θ of the synthetic aperture c and synthetic aperture angle accumulation θ syn , determine the synthetic aperture time T to obtain the required resolution s and the synthetic aperture length L s , as the imaging guidance flight time and flight distance of the short-range missile at the last moment.

[0150] According to the central slant angle θ of the synthetic aperture c and synthetic aperture angle accumulation θ syn , combined with the closest slant distance R0 and the missile-carrying platform motion speed v, the missile imaging guidance flight distance L at the final moment s The calculation of is as follows:

[0151] L s =R0 tan(θ s )-R0 tan(θ s -θ syn ) (20)

[0152] Final missile imaging guidance flight time T s The calculation of is as follows:

[0153]

[0154] Step 8: Calculate the pitch angle φ at the end of synthetic aperture imaging guidance based on the radar field of view angle e , yaw angle ψ s , determine the pitch angle φ at the end of synthetic aperture imaging guidance e , yaw angle ψ e Is it within the frame angle range specified in the technical parameters? Calculate the projectile-target distance R e , determine the missile-target distance R at the end of synthetic aperture imaging guidance e Whether it is within the radar imaging guided strike range;

[0155] If the pitch angle φ e , yaw angle ψ e All are within the frame angle range, and the projectile-target distance R e If the missile is within the radar imaging guided strike range, the guidance system design is successful; otherwise, return to step 2 and redesign.

[0156] The missile-target distance R at the final moment of synthetic aperture imaging guidance e The calculation is:

[0157]

[0158] Pitch angle φ at the final moment e The calculation is:

[0159]

[0160] Yaw angle ψ at the final moment e The calculation is:

[0161]

[0162] If the pitch angle φ at the end e , yaw angle ψ e All within the radar seeker frame angle range (i.e. the maximum limit of the pitch frame angle φ max , the maximum limit of yaw frame angle ψ max ), the pitch angle and yaw angle conditions required for the imaging of the short-range tactical missile radar seeker meet the seeker viewing angle range; if the missile-target distance R at the end moment e In the radar imaging guidance strike range (minimum strike range Maximum strike distance ), then the tactical missile can strike the target.

[0163] Example:

[0164] Step 1: Determine the air-to-ground scenario, the target type is an armored vehicle, and the short-range tactical missile radar guidance mode is two-dimensional imaging guidance with a resolution of ρ r ×ρ a : 0.5m×0.5m, signal wavelength λ: 3.2mm, maximum limit of pitch angle The maximum yaw angle limit is 20°. max is 20°, the striking distance (R min ,R max ) is (2km,5km).

[0165] Step 2: The initial position of platform M is (0, -44m, 200m) and the position of target T is (867.5m, 4876.1m, 0), so the initial range R is s =5000m, initial yaw angle φ s =10°, initial pitch angle The lower viewing angle α = 12.98°, and the initial oblique viewing angle θ is obtained s =79.74°.

[0166] Step 3: According to the range resolution ρ r =0.5m, lower viewing angle α = 12.98°, and the range emission bandwidth B is obtained r =307.87MHz.

[0167] Step 4 and step 5 construct the equation θ c =f1(θ syn ) and θ c =f2(θsyn ).

[0168] Step 6: Use the Newton-Raphson method to solve the central slant angle θ of the synthetic aperture c =79.65° and the synthetic aperture angle accumulation θ syn =0.18°.

[0169] Step 7: According to the solution, obtain the synthetic aperture time T s =0.35s, synthetic aperture length L s =88.06m, azimuth Doppler bandwidth Br =89.8082Hz, azimuth center frequency is 154.12kHz, and azimuth bandwidth sampling rate is 8.0827kHz.

[0170] Step 8: Calculate the pitch angle φ at the end of synthetic aperture imaging guidance based on the field of view angle e =2.33°, yaw angle ψ e =10.18°, the distance between the projectile and the target at the final moment is R e = 4913.4m, judge that the pitch angle and yaw angle of synthetic aperture imaging guidance at the final moment meet the frame angle range, and the missile-target distance at the final moment is R e Within striking distance.

[0171] Step 9: Use the radar imaging algorithm to verify the system design. This solution uses the BP algorithm as an example to perform imaging. The imaging indicators are shown in Table 1.

[0172] Table 1 Index parameters

[0173]

[0174] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. A design method for a missile-borne radar forward oblique imaging guidance system, characterized in that: include: Step 1: Determine the technical parameters required for tactical missile radar guidance based on the combat scenario, target type, and target recognition probability requirements; Step 2: Utilizing the radar seeker detection capability in the technical parameters, combined with the missile altitude and the target position measured by the fire control radar, the tactical missile initial position, initial missile-target range, initial yaw angle, initial pitch angle, and downward viewing angle are calculated based on the large forward squint initial squint angle; wherein the large forward squint initial squint angle satisfies the large forward squint angle constraint in the technical parameters; Step 3: Determine the range signal transmission bandwidth based on the range imaging resolution requirements of the radar seeker in the technical parameters and the downward viewing angle; Step 4: Based on the requirements for the radar seeker's azimuth imaging resolution in the technical parameters, combined with the initial squint angle, the wavelength of the transmitted signal, and the velocity of the missile-carrying platform, determine the relationship between the synthetic aperture center squint angle and the synthetic aperture angle accumulation as the first equation; Step 5: Based on the scene geometry requirements of the radar seeker's large forward squint system, combined with the initial squint angle and the initial missile-target distance, the relationship between the synthetic aperture center squint angle and the synthetic aperture angle accumulation is determined as the second equation; Step 6: Solve the first and second equations together using the Newton-Raphson method to obtain the central squint angle of the synthetic aperture and the accumulation of the synthetic aperture angle. Step 7: Determine the synthetic aperture time and synthetic aperture length required to achieve the required resolution based on the accumulated synthetic aperture central squint angle and synthetic aperture rotation angle, which serve as the imaging guidance flight time and flight distance of the short-range missile at the final moment. Step 8: Calculate the pitch angle and yaw angle at the end of the synthetic aperture imaging guidance according to the radar field of view angle, and determine whether the pitch angle and yaw angle at the end of the synthetic aperture imaging guidance are within the frame angle range specified in the technical parameters; calculate the missile-target distance, and determine whether the missile-target distance at the end of the synthetic aperture imaging guidance is within the radar imaging guidance strike range; If the pitch angle and yaw angle are both within the frame angle range, and the missile-target distance is within the radar imaging guidance strike range, then the guidance system design is successful; otherwise, return to step 2 and redesign.

2. The missile-borne radar forward oblique imaging guidance system design method according to claim 1 is characterized in that: The technical parameters that the tactical missile radar guidance needs to meet include: Range resolution ρ of radar seeker r and azimuth resolution ρ a , radar seeker detection capability Radar seeker frame angle range, including the maximum limit of the pitch frame angle φ max and the maximum limit of the yaw frame angle ψ max , radar imaging guidance strike range, including minimum strike range and maximum striking distance Radar seeker 3dB beamwidth β 3dB , the constraints of the squint angle in the large front squint scene, including the minimum squint angle under large front squint and the maximum anterior strabismus angle under large anterior strabismus 3. The missile-borne radar forward oblique imaging guidance system design method according to claim 1 is characterized in that: The method of calculating the initial position, initial missile-target distance, initial yaw angle, initial pitch angle, and downward viewing angle of the tactical missile based on the initial large forward squint angle includes: Initial position of short-range tactical missile (x m ,y m ,H) is based on the target position (x t ,y t ,z t ) is the dot, the initial projectile-target distance R s The initial target distance R is on the circle with radius s Should be less than or equal to the radar seeker detection capability And the oblique angle with the target position is Calculate the missile initial position (x m ,y m ,H) is: Seeker initial yaw angle φ s is the angle between the projection of the target azimuth vector on the horizontal plane and the positive x-axis; calculate the initial yaw angle φ of the seeker s for: Determine the initial yaw angle φ of the seeker s , must be less than or equal to the radar seeker field of view angle limit; Initial pitch angle ψ s is the angle between the projection of the target azimuth vector on the horizontal plane and the positive x-axis; calculate the initial pitch angle ψ s for: Determine the initial pitch angle ψ of the seeker s , must be less than or equal to the radar seeker field of view angle limit where β 3dB is the 3dB beam width of the radar seeker, ψ max is the maximum limit of the yaw frame angle; The seeker uses a large forward squint initial squint angle θ s and the initial yaw angle of the seeker φ s and the initial pitch angle of the seeker ψ s The relationship is: i s =arcsin(cosφ s ·cosψ s ) (4) The lower viewing angle α is the angle between the minimum slant range R0 and the self-height of the radar seeker M. The lower viewing angle α is calculated as:

4. The missile-borne radar forward oblique imaging guidance system design method according to claim 1 is characterized in that: The bandwidth of the signal transmission from the determined distance is expressed as: Where c is the speed of light, ρ r is the imaging resolution in the range direction, and α is the downward viewing angle.

5. The missile-borne radar forward oblique imaging guidance system design method according to claim 1 is characterized in that: The construction process of the first equation is: The forward oblique imaging guidance system is in the synthetic aperture time range (t s ,t e ) observes the imaging area, and the synthetic aperture time is T s =t e -t s , where t s ,t e are the initial and final moments respectively; the moment at the center of the synthetic aperture is t c ; For the scene center point target, at the initial synthetic aperture time t s , the initial oblique angle is θ s , then the instantaneous Doppler frequency at the initial moment is: At the end of the synthetic aperture t e , the oblique angle is θ e , then the instantaneous Doppler frequency at the last moment is: Then, during the entire observation time, the Doppler bandwidth of the echo signal at the center of the scene is: The azimuth resolution can be calculated as: Solve equation (10) to get θ c ,Right now: From this, we can establish the first equation θ c =f1(θ syn ).

6. The missile-borne radar forward oblique imaging guidance system design method according to claim 1 is characterized in that: The construction process of the second equation is: Initial target distance R s The projected length in the direction of motion of the missile-carrying platform is R s sinθ s , the distance between the projectile and the target at the last moment is R e The projected length in the direction of motion of the missile-carrying platform is R s cosθ s tan(θ s -θ syn ), the distance between the projectile and the target at the center of the synthetic aperture R c The projected length in the direction of motion of the missile-carrying platform is R0tanθ c , then: R s sinth s -R s cosθ s ·tan(θ s -θ syn )=2R s sinth s -2R s cosθ s ·tanθ c (12) Simplified: -cosθ s tan(θ s -θ syn )=sinθ s -2cosθ s tanθ c (13) Solve equation (13) to get θ c ,Right now: This allows us to establish the second equation θ c =f2(θ syn ).

7. The missile-borne radar forward oblique imaging guidance system design method according to claim 1 is characterized in that: The first equation and the second equation are solved by the Newton-Raphson method to obtain the central squint angle of the synthetic aperture and the accumulation of the synthetic aperture rotation angle, including: First, we need to c =f1(θ syn ) is rewritten as F1(θ c ,θ syn )=0, and θ c =f2(θ syn ) is rewritten as F2(θ c ,θ syn )=0, the system of equations can be obtained as follows: Next, suppose the solution of the equation x=[θ c ,θ syn ] T , the superscript T represents the transpose; the vector function F(x), Jacobian matrix J(x) and Newton iteration formula are defined as follows: The vector function F(x) is: The Jacobian matrix J(x) is: The Newton iteration formula is: x n+1 =x n -J(x n ) -1 F(x n ) (18) Finally, the Newton-Raphson method is used to solve the equation x = [θ c ,θ syn ] T , get the central slant angle θ of the synthetic aperture c and synthetic aperture angle accumulation θ syn , where x n Represents the x solved at the nth iteration.

8. The missile-borne radar forward oblique imaging guidance system design method according to claim 1 is characterized in that: According to the central slant angle θ of the synthetic aperture c and synthetic aperture angle accumulation θ syn , combined with the closest slant distance R0 and the missile-carrying platform motion speed v, the missile imaging guidance flight distance L at the final moment s The calculation of is as follows: L s =R0tan(θ s )-R0tan(θ s -θ syn ) (20) Final missile imaging guidance flight time T s The calculation of is as follows:

9. The missile-borne radar forward oblique imaging guidance system design method according to claim 1, characterized in that: The missile-target distance R at the final moment of synthetic aperture imaging guidance e The calculation is: Pitch angle φ at the final moment e The calculation is: Yaw angle ψ at the final moment e The calculation is: If the pitch angle φ at the end e , yaw angle ψ e The maximum limit of the pitch frame angle is φ max , maximum limit of yaw frame angle ψ max If the distance between the missile and the target at the end is R, then the pitch angle and yaw angle required for the imaging of the radar seeker of the short-range tactical missile meet the range of the seeker's viewing angle. e At minimum striking distance Maximum strike distance Within, tactical missiles can hit the target.

10. A terminal device comprising a processor, a memory, and a computer program stored in the memory; characterized in that: When the processor executes the computer program, it implements the design method of the missile-borne radar forward oblique imaging guidance system according to any one of claims 1 to 9.

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