Missile-borne radar forward oblique imaging guidance system design method

Abstract

The invention provides a missile-borne radar forward-skew imaging guidance system design method, which comprises the following steps: according to a combat scene of a short-range missile and an attacked target type, determining range resolution and azimuth resolution requirements of a small short-range tactical missile radar seeker meeting identification requirements; on the basis of radar seeker frame angle constraints, a small short-range tactical missile radar guidance geometrical relationship and a radar imaging mode are established, a synthetic aperture rotation angle accumulation and central squint angle relationship is constructed, then missile flight path, duration and other parameters are designed, and a small short-range tactical missile imaging guidance system is formed. According to the method, the target detection and recognition capability of the small tactical missile can be improved, and method and technical support is provided for design of a radar guidance small tactical missile imaging guidance system.

Description

Technical Field

[0001] The 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 design of ballistic trajectories often adopts the method of maintaining nearly straight ballistic trajectories, which is conducive to improving the flight speed and penetration capability of small tactical missiles and reducing energy loss during flight. In this ballistic mode, the flight path of the missile usually does not involve significant trajectory bending. Unlike the optoelectronic guidance system, for radar-guided missiles, since the missile flies straight to the target, this results in the radar seeker being able to detect and identify the target only through one-dimensional range images when performing target detection. Although the one-dimensional range image can be used for target detection and identification, the target information obtained is still limited compared to the two-dimensional image. On the one hand, the one-dimensional range image cannot provide detailed information about the target in the horizontal direction, which may make it difficult for the missile to distinguish the true shape and size of the target during the attack, thereby affecting the strike accuracy. On the other hand, the one-dimensional range image has a weak ability to identify the target, especially in a complex battlefield environment, and is easily affected by factors such as noise and interference, which makes the missile face a high risk of misidentification when performing tasks.

[0003] Two-dimensional imaging can obtain more dimensional information of the target and extract richer target features for accurate description of target characteristics. After a short-range tactical missile locks on a detected target, the target will always be in the field of view of the missile seeker. In order to obtain higher resolution, a beamforming mode is used for imaging processing. Therefore, how to design a two-dimensional imaging guidance system for short-range tactical missiles and improve the missile's target detection and recognition capabilities is of great significance to the technical field of small short-range tactical missile radar homing guidance systems. Summary of the invention

[0004] The purpose of the present invention is to provide a missile-borne radar forward oblique imaging guidance system design method for planning the ballistic path of a tactical missile and improving 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 that must be met by tactical missile radar guidance based on combat scenarios, target types, and target recognition probability requirements;

[0008] Step 2, using 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 distance, initial yaw angle, initial pitch angle and downward viewing angle are calculated according to the large forward squint initial squint angle; wherein the large forward squint initial squint angle satisfies the large forward squint angle constraint condition in the technical parameters;

[0009] Step 3, according to the requirements of the range imaging resolution of the radar seeker in the technical parameters and combined with the lower viewing angle, determine the range signal transmission bandwidth;

[0010] Step 4, according to the requirements of the azimuth imaging resolution of the radar seeker in the technical parameters, combined with the initial squint angle, the wavelength of the transmitted signal and the movement speed of the missile-carrying platform, determine the relationship between the synthetic aperture center squint angle and the synthetic aperture rotation angle accumulation as the first equation;

[0011] Step 5, according to the requirements of the scene geometry of the radar seeker large forward squint system, combined with the initial squint angle and the initial missile-target distance, determine the relationship between the synthetic aperture center squint angle and the synthetic aperture rotation angle accumulation as the second equation;

[0012] Step 6, combining the first equation and the second equation, and solving them by the Newton-Raphson method to obtain the central squint angle of the synthetic aperture and the accumulation of the synthetic aperture rotation angle;

[0013] Step 7, according to the accumulation of the central slant angle of the synthetic aperture and the rotation angle of the synthetic aperture, determine the synthetic aperture time and synthetic aperture length for obtaining the required resolution, which are used as the imaging guidance flight time and flight distance of the short-range missile at the end moment;

[0014] Step 8, according to the radar field of view angle, calculate the pitch angle and yaw angle at the end of the synthetic aperture imaging guidance, and judge whether the pitch angle and yaw angle at the end of the synthetic aperture imaging guidance are within the frame angle range in the technical parameters; calculate the missile-target distance, and judge whether the missile-target distance at the end of the synthetic aperture imaging guidance is within the radar imaging guidance strike distance 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, the guidance system design is successful; otherwise, return to step 2 and redesign.

[0016] Furthermore, the technical parameters that the tactical missile radar guidance needs to meet include:

[0017] Range resolution of radar seeker ρ 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 guided strike range, including minimum strike range and maximum striking distance Radar seeker 3dB beam width β 3dB , the constraint conditions 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] Further, 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 according to the initial squinting angle of the large forward squinting 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 distance R s The initial projectile distance R is on a circle with a radius of s Should be less than or equal to the radar seeker detection capability And the oblique angle with the target position is Calculate the initial position of the missile (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 of the seeker φ s and the initial pitch angle ψ of the seeker s The relationship is:

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

[0029] The lower viewing angle α is the angle between the shortest 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 determine the signal transmission bandwidth is expressed 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 time and the final time respectively; the time 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, time 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 projectile-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 is 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 combined to obtain the synthetic aperture center squint angle and the synthetic aperture rotation angle accumulation by the Newton-Raphson method, 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 combined equations are:

[0056]

[0057] Next, suppose that 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 the synthetic aperture angle accumulation θ syn , where x n Represents the solution x at the nth iteration.

[0065] Further, according to the central slant angle θ of the synthetic aperture c and the synthetic aperture angle accumulation θ syn , combined with the closest slant distance R0 and the velocity v of the missile-carrying platform, the missile imaging guidance flight distance L at the end 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] Final pitch angle φ e The calculation is:

[0072]

[0073] Yaw angle ψ at the end 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 final moment is R e At minimum striking distance Maximum striking 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 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. A target with richer targets can be obtained through two-dimensional imaging, and trajectory conditions are constructed for radar two-dimensional imaging that meets recognition requirements. The target detection and recognition capabilities of small tactical missiles can be improved, and a method and technical support are provided for the design of a radar-guided small tactical missile imaging guidance system. 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 It is a ballistic trajectory diagram in a single target scenario of the method of the present invention;

[0082] Figure 4 This is an 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 curve of the target at the missile-borne synthetic aperture distance of the method of the present invention;

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

[0086] The basic idea of ​​the present invention is: according to the combat scenario of the short-range missile and the type of the target attacked, the range resolution and azimuth resolution requirements of the radar seeker of a small short-range tactical missile that meet the identification needs are determined; based on the frame angle constraint of the radar seeker, the small short-range tactical missile radar guidance geometric relationship and radar imaging mode are established, the relationship between the synthetic aperture angle accumulation and the central oblique angle is constructed, and then the missile flight path, duration and other parameters are designed 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 that the tactical missile radar guidance needs to meet based on the combat scenario, target type, and target recognition probability requirements, including:

[0089] Range resolution of radar seeker ρ 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 the yaw frame angle ψ max ), radar imaging guided strike range (i.e. minimum strike range Maximum striking distance ), radar seeker 3dB beam width β 3dB , the constraint condition of the squinting angle in the large front squinting scene (i.e. the minimum squinting angle under large front squinting) Maximum anterior strabismus angle under large anterior strabismus ).

[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, that is,

[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 distance R s The initial projectile distance R is on a circle with a radius of 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 initial position of the missile (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 of the seeker φ s and the initial pitch angle ψ of the seeker s The relationship is:

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

[0102] The lower viewing angle α is the angle between the shortest 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 According to the requirements, combined with the viewing angle α, the distance to signal transmission bandwidth B is determined 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 oblique angle θ of the synthetic aperture. c and the synthetic aperture angle accumulation θ syn The relationship between θ and c =f1(θ syn ). The expression building 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 time and the final time respectively; the time at the center of the synthetic aperture is t c .

[0109] For the target at the center of the scene, 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, time 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: According to the requirements of the scene geometry of the radar seeker large forward squint system, combined with the initial squint angle θ s and the initial projectile-target distance R s , determine the central slant angle θ of the synthetic aperture c and the synthetic aperture angle accumulation θ syn The relationship between the two equations is as follows: c =f2(θ syn ). The expression building process is as follows:

[0121] The synthetic aperture starting angle θ obtained in step 2 s , initial projectile-target distance R s , the closest slant distance between the projectile and the target R0, combined with the scene geometry of the large front squint system, can be obtained through 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 the missile-carrying platform movement 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 the missile-carrying platform movement 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 projectile-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, combine 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 the 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 combined equations are:

[0131]

[0132] Next, suppose that 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 condition is met, output

[0149] Step 7: Based on the central oblique angle θ of the synthetic aperture c and the 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-guided flight time and distance of short-range missiles at the last moment.

[0150] According to the central slant angle θ of the synthetic aperture c and the synthetic aperture angle accumulation θ syn , combined with the closest slant distance R0 and the velocity v of the missile-carrying platform, the missile imaging guidance flight distance L at the end 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 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 guidance system 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 end of synthetic aperture imaging guidance e The calculation is:

[0157]

[0158] Final pitch angle φ e The calculation is:

[0159]

[0160] Yaw angle ψ at the end 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 the yaw frame angle ψ max ), then the pitch angle and yaw angle conditions required for the imaging of the short-range tactical missile radar seeker meet the range of the seeker's viewing angle; if the missile-target distance R at the final moment e In the radar imaging guidance strike range (minimum strike distance Maximum striking distance ) within the range of 200 km / h, then tactical missiles 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). The initial missile-target distance 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 distance resolution ρ r =0.5m, lower viewing angle α=12.98°, and the range transmission bandwidth B is obtained r =307.87MHz.

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

[0168] Step 6: Use the Newton-Raphson method to obtain 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 result, 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 in the imaging algorithm as an example to perform result 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 embodiments of the present application, and should all be included in the protection scope 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 that must be met by tactical missile radar guidance based on combat scenarios, target types, and target recognition probability requirements; Step 2, using 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 distance, initial yaw angle, initial pitch angle and downward viewing angle are calculated according to the large forward squint initial squint angle; wherein the large forward squint initial squint angle satisfies the large forward squint angle constraint condition in the technical parameters; Step 3, according to the requirements of the range imaging resolution of the radar seeker in the technical parameters and combined with the lower viewing angle, determine the range signal transmission bandwidth; Step 4, according to the requirements of the azimuth imaging resolution of the radar seeker in the technical parameters, combined with the initial squint angle, the wavelength of the transmitted signal and the movement speed of the missile-carrying platform, determine the relationship between the synthetic aperture center squint angle and the synthetic aperture rotation angle accumulation as the first equation; Step 5, according to the requirements of the scene geometry of the radar seeker large forward squint system, combined with the initial squint angle and the initial missile-target distance, determine the relationship between the synthetic aperture center squint angle and the synthetic aperture rotation angle accumulation as the second equation; Step 6, combining the first equation and the second equation, and solving them by the Newton-Raphson method to obtain the central squint angle of the synthetic aperture and the accumulation of the synthetic aperture rotation angle; Step 7, according to the accumulation of the central slant angle of the synthetic aperture and the rotation angle of the synthetic aperture, determine the synthetic aperture time and synthetic aperture length for obtaining the required resolution, which are used as the imaging guidance flight time and flight distance of the short-range missile at the end moment; Step 8, according to the radar field of view angle, calculate the pitch angle and yaw angle at the end of the synthetic aperture imaging guidance, and judge whether the pitch angle and yaw angle at the end of the synthetic aperture imaging guidance are within the frame angle range in the technical parameters; calculate the missile-target distance, and judge whether the missile-target distance at the end of the synthetic aperture imaging guidance is within the radar imaging guidance strike distance 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, 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 of radar seeker ρ 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 guided strike range, including minimum strike range and maximum striking distance Radar seeker 3dB beam width β 3dB , the constraint conditions 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 according to the initial squinting angle of the large forward squinting 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 distance is R s The initial projectile distance R is on a circle with a radius of s Should be less than or equal to the radar seeker detection capability And the oblique angle with the target position is Calculate the initial position of the missile (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 ψ of the seeker s The relationship is: i s =arcsin(cosφ s ·cosψ s ) (4) The lower viewing angle α is the angle between the shortest 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 distance-determined signal transmission bandwidth 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 time and the final time respectively; the time 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, time 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 projectile-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 is 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 combined to obtain the synthetic aperture central squint angle and the synthetic aperture rotation angle accumulation by the Newton-Raphson method, including: 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 combined equations are: Next, suppose that 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 the synthetic aperture angle accumulation θ syn , where x n Represents the solution x 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 the synthetic aperture angle accumulation θ syn , combined with the closest slant distance R0 and the velocity v of the missile-carrying platform, the missile imaging guidance flight distance L at the end 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 is characterized in that: The missile-target distance R at the end of synthetic aperture imaging guidance e The calculation is: Final pitch angle φ e The calculation is: Yaw angle ψ at the end 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 final moment is R 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 1-9.

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