A method for obtaining supersonic projectile terminal parameters using a single array

Abstract

The present invention relates to a target position measurement method, and more specifically, to a method for obtaining supersonic projectile terminal parameters using a single array. This method addresses the technical issues inherent in conventional acoustic methods for measuring supersonic projectile terminal parameters, such as the large number of measurement points, difficulty in rapid deployment, high economic costs, complex installation, and difficulty ensuring communication, hindering large-scale testing. The method comprises the following steps: 1) acquiring shock wave and blast wave signals; 2) signal processing; 2.1) calculating a north deviation angle θ; 2.2) calculating the average arrival time of five shock wave and blast wave signals and calculating the arrival time difference Δt, using which the distance d from the impact point to the acoustic array, the projectile velocity v, and the explosion time t are calculated; and 2.3) obtaining the impact point position parameters using θ, d, and the position of the acoustic array itself in the geodetic coordinate system. This method requires only a single acoustic array to estimate the impact point position, explosion time, and projectile velocity.

Description

Technical Field

[0001] The present invention relates to a target position measurement method, in particular to a method for obtaining terminal parameters of a supersonic projectile using a single array. Background Art

[0002] In the field of target position measurement, passive non-contact measurement is a commonly used method for measuring target information because it does not affect the target and is highly concealed. Acoustic measurement systems are a type of passive non-contact measurement system. They offer low cost, all-weather operation, immunity to smoke interference, and a large measurement range, making them commonly used for measuring target positions over large areas.

[0003] However, traditional acoustic measurement methods require at least three measurement points. This large number of measurement points in the measurement system leads to high costs, difficulty in rapid deployment, and high complexity and time costs in installation. Furthermore, the large number of measurement points results in a long deployment cycle. When measuring over large areas in the field, it is difficult to ensure the necessary communication and transportation, hindering large-scale testing.

[0004] When measuring parameters such as the impact point location over a large area in the field, the fewer the number of measurement points used, the lower the complexity, time and economic cost of the measurement system layout and installation, and the easier it is to ensure communication. Therefore, it is necessary to find a method for measuring the terminal parameters of supersonic projectiles with a small number of measurement points. Summary of the Invention

[0005] The purpose of the present invention is to solve the technical problems of traditional acoustic measurement methods of supersonic projectile terminal parameters, such as the large number of measurement points, difficulty in rapid deployment, high economic cost, complex layout and installation, and difficulty in ensuring communication, which are not conducive to large-scale experiments. Instead, a method for obtaining supersonic projectile terminal parameters with a single array is provided.

[0006] The concept of the present invention is that a projectile generates a shock wave during supersonic flight. As it falls near vertically (the angle between its direction of motion and the ground is close to 90 degrees), the shock wave propagates at the speed of sound toward the acoustic array at the measurement point. The shock wave arriving at the acoustic array originates from a single point on the trajectory, known as the closest approach point. The acoustic array receives the shock wave from the closest approach point and then receives the blast wave from the impact point. Using an acoustic array processing algorithm, the directions of the shock and blast waves are determined. The directions and arrival time differences of the shock and blast waves are then integrated to determine the terminal parameters of the projectile using a single acoustic array. Based on the above concept, the present invention proposes a method for obtaining the terminal parameters of a supersonic projectile with a single array. First, five acoustic wave signals from a three-dimensional cross-shaped acoustic array are collected, a time delay estimation window is selected, and the time delay of the signal is estimated by the cross-correlation delay estimation method. The direction of the shock wave and the blast wave is obtained by using an array signal processing algorithm in combination with the spatial position of the acoustic array. The arrival times of the five shock wave and blast wave signals are averaged to obtain the arrival times of the shock wave and blast wave, respectively. The shock wave arrives at the array ahead of the blast wave, and the terminal parameters are obtained by fusion calculation using the arrival time difference.

[0007] The technical solution of the present invention:

[0008] A method for obtaining terminal parameters of a supersonic projectile using a single array, wherein the terminal parameters include impact point position, explosion time t, and projectile velocity v. The method is special in that it includes the following steps:

[0009] 1) Acquisition signal

[0010] 1.1) Install a 5-element, cross-shaped acoustic array at the measurement point, based on the predetermined impact point. Align the bottom of the array parallel to the ground. The four microphones at the bottom of the array are numbered 1, 2, 3, and 4 in a clockwise direction, with the top microphone numbered 5.

[0011] 1.2) Use the signal acquisition instrument to synchronously collect the five shock wave and explosion wave signals of the acoustic array and record the arrival time t of the five shock wave signals s and the arrival time t of the five explosion wave signals i ;

[0012] 2) Signal processing

[0013] 2.1) By the formula θ=θ0-θ Li +π is calculated to get the angle θ from the north;

[0014] A three-dimensional coordinate system is established with the center O of the acoustic array as the origin and the directions of microphones 1, 4, and 5 as the X-axis, Y-axis, and Z-axis, respectively. The X-axis is defined as the array reference direction, and θ0 is the angle between the array reference direction and the true north direction; θ Li is the angle between the projection of the explosion wave arrival direction in the XOY plane and the X axis;

[0015] 2.2) Through the formula and The average arrival time of the five shock wave signals is calculated separately and the average arrival time t of the explosion wave signal i The distance d from the impact point to the acoustic array, the projectile velocity v, and the explosion time t are calculated using the following formula:

[0016]

[0017]

[0018]

[0019]

[0020] c is the propagation rate of the acoustic signal;

[0021] is the angle between the shock wave arrival direction and the XOY plane;

[0022] is the angle between the explosion wave arrival direction and the XOY plane;

[0023] 2.3) The impact point position is obtained using θ, the distance d from the impact point to the acoustic array, and the position of the acoustic array itself in the geodetic coordinate system.

[0024] Furthermore, in step 2.1), θ Li Calculated by the following formula:

[0025] θ Li =atan2(k iy ,k ix )

[0026]

[0027] in, is the blast wave vector where the blast wave arrives, The direction of the explosion wave is the direction of arrival, and the direction of the impact point relative to the measuring point is

[0028] Further, in step 2.1), the The method for obtaining the delay is as follows: the five explosion wave signals of microphones 1, 2, 3, 4 and 5 are cross-correlated and time delay estimation is performed in pairs, and the delay estimation value sequence τ = [τ 12 , τ 13 , τ 14 , τ 15 , τ 23 , τ 24 , τ 25 , τ34 , τ 35 , τ 45 ] T , where the superscript T represents the transpose of the vector; the five microphone positions are paired in pairs to obtain 10 direction vectors, which can be expressed as a matrix R = [r 12 ,r 13 ,r 14 ,r 15 ,r 23 ,r 24 ,r 25 ,r 34 ,r 35 ,r 45 ], where r 12 is the vector from microphone 1 to microphone 2, and so on;

[0029] The explosion wave vector is obtained by the following formula

[0030]

[0031] Furthermore, in step 1, the radius of the acoustic array is greater than or equal to 0.7 m.

[0032] Furthermore, in step 1, the distance between the measuring point and the impact point is greater than 750m.

[0033] The beneficial effects of the present invention are:

[0034] 1. The present invention provides a method for obtaining terminal parameters of a supersonic projectile using a single array. The method utilizes the arrival times of shock waves and blast waves generated when a supersonic projectile falls at a near-vertical angle to obtain the directions of arrival of the shock waves and blast waves. The directions of arrival of the shock waves and blast waves, as well as the time difference of arrival, are combined to enable a single acoustic array to obtain terminal parameters such as the impact point position, explosion time, and projectile velocity. The method can be applied to obtain terminal parameters of a wide range of supersonic projectiles falling near vertically, greatly simplifying the operating process, reducing the cost of the measurement system, the difficulty of field deployment, and the support requirements. The method can be quickly deployed and is suitable for measuring the impact point position, explosion time, and projectile velocity of supersonic projectiles falling near vertically at long distances.

[0035] 2. The present invention provides a method for obtaining terminal parameters of a supersonic projectile using a single array. When a supersonic projectile is falling nearly vertically, this method only requires a single acoustic array to estimate the impact point position, explosion time, and projectile velocity. The calculation is simple and effective, and can be used to obtain terminal parameters of the projectile online in real time, facilitating its application and promotion.

[0036] 3. The present invention provides a method for obtaining the terminal parameters of a supersonic projectile with a single array. The method requires simple guarantees in large-area field measurement applications, has a short system deployment preparation process, can be deployed quickly, is conducive to the implementation of large-scale tests, and is suitable for rapid deployment and large-area mobile measurement in the field.

[0037] 4. The present invention provides a method for obtaining terminal parameters of a supersonic projectile using a single array. The radius of the acoustic array is ≥0.7m, ensuring the accuracy of the acoustic array direction finding.

[0038] 5. The present invention provides a method for obtaining terminal parameters of a supersonic projectile using a single array. The distance between the measuring point and the impact point is greater than 750m, so that the blast wave and shock wave are completely separated on the waveform diagram, ensuring the accuracy of the measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 2 is a schematic diagram of the structure of an acoustic array in an embodiment of a method for obtaining terminal parameters of a supersonic projectile using a single array according to the present invention;

[0040] Figure 2 This is a waveform diagram of shock waves and explosion waves obtained in an embodiment of a method for obtaining terminal parameters of a supersonic projectile using a single array according to the present invention;

[0041] Figure 3 Schematic diagram of a north angle θ in an embodiment of a method for obtaining terminal parameters of a supersonic projectile using a single array according to the present invention;

[0042] Figure 4 It is a schematic diagram of the acoustic array positioning model in an embodiment of a method for obtaining terminal parameters of a supersonic projectile with a single array according to the present invention. DETAILED DESCRIPTION

[0043] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments.

[0044] The present invention provides a method for obtaining terminal parameters of a supersonic projectile using a single array, comprising the following steps:

[0045] 1) Acquisition signal

[0046] 1.1) Install the three-dimensional five-element cross-shaped acoustic array at the measurement point according to the predetermined impact point, such as Figure 1 As shown, the four microphones at the bottom of the array, located on the same horizontal plane, are numbered 1, 2, 3, and 4 in a clockwise direction, with the top microphone numbered 5. During installation, to separate the shock wave and blast wave waveforms, the array was placed in an easily accessible location 750 meters from the intended impact point. The plane containing the four microphones at the bottom of the array was adjusted to be parallel to the ground. To ensure accuracy, the array radius was maintained at no less than 0.7 meters.

[0047] 1.2) Use the signal acquisition instrument to synchronously collect the five shock wave and explosion wave signals of the acoustic array, and the waveform of one of the shock wave and explosion wave is as follows: Figure 2 As shown; and record the arrival time t of the five shock wave signals s and the arrival time t of the five explosion wave signals i .

[0048] 2) Signal processing

[0049] The five explosion wave signals of microphones 1, 2, 3, 4 and 5 are cross-correlated and time delay is estimated in pairs, and the delay estimation value sequence τ=[τ 12 , τ 13 , τ 14 , τ 15 ,τ23,τ 24 , τ 25 , τ 34 , τ 35 , τ 45 ] T , where the superscript T represents the transpose of the vector; the five microphone positions are paired in pairs to obtain 10 direction vectors, which can be expressed as a matrix R = [r 12 ,r 13 ,r 14 ,r 15 ,r 23 ,r 24 ,r 25 ,r 34 ,r 35 ,r 45 ], where r 12 is the vector from microphone 1 to microphone 2, and so on;

[0050] The wave vector of the explosion wave is obtained by the following formula

[0051]

[0052] With the array center O as the origin, a three-dimensional coordinate system is established with the directions of microphones 1, 4, and 5 as the X-axis, Y-axis, and Z-axis, respectively. The XOY plane is as follows: Figure 3 As shown, in the coordinate system, the explosion wave vector The direction of is the arrival direction of the explosion wave, and the direction of the impact point relative to the acoustic array is Wave vector of shock wave arrival Press explosion wave vector The calculation method is calculated, The direction of the shock wave is the direction of arrival, and the direction of the closest point of the shock wave on the ballistic trajectory relative to the array is the opposite direction of the shock wave arrival direction. shock wave vector

[0053] The pitch angle of the shock wave arrival direction can be calculated from the shock wave vector The azimuth angle θ of the explosion wave arrival direction can be calculated by the explosion wave vector. Li , pitch angle

[0054]

[0055] θ Li =atan2(k iy ,k ix )

[0056]

[0057] The relationship between the azimuth angle and the pitch angle in the coordinate system is as follows Figure 4 As shown, the pitch angle is the angle between the shock wave arrival direction and the XOY plane, θ Li is the angle between the projection of the explosion wave arrival direction in the XOY plane and the X axis, the pitch angle It is the angle between the explosion wave arrival direction and the XOY plane.

[0058] In the coordinate system, the X axis is defined as the array reference direction, θ0 is defined as the angle between the array reference direction and the true north direction, clockwise is positive, and the azimuth angle θ of the explosion wave arrival direction is Li Combined with the array reference north direction θ0, through the formula θ=θ0-θ Li +π is used to calculate the north angle θ of the impact point relative to the array.

[0059] The arrival times of shock waves and explosion waves received by the five microphones are t s and t i , through the formula and The average arrival time of the five shock wave and explosion wave signals is calculated respectively, and then the following formula is used to calculate the average arrival time of the five shock wave and explosion wave signals.

[0060]

[0061] like Figure 4 As shown in the figure, P is the acoustic array, S is the impact point, and T is the closest point of the shock wave. and shock cone angle The distance d from the impact point to the acoustic array, the velocity v of the projectile, and the explosion time t are obtained:

[0062]

[0063]

[0064]

[0065] r is the distance from the closest point of the shock wave to the acoustic array;

[0066] c is the propagation velocity of the acoustic signal.

[0067] Finally, combining the obtained angle of impact point relative to the acoustic array, the distance d, and the position of the acoustic array in the geodetic coordinate system (latitude lat, longitude lon, elevation h0), the Matlab function [latout, lonout] = reckon(lat, lon, d, θ, ellipsoid) (where ellipsoid is the reference ellipsoid) and The position of the impact point (latitude latout, longitude lonout, altitude h) can be estimated.

[0068] The above description is only the best specific implementation method of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or replacements that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A method for obtaining terminal parameters of a supersonic projectile using a single array, wherein the terminal parameters include impact point location, explosion time t, and projectile velocity v, characterized in that the method comprises the following steps: 1) Acquisition signal 1.1) Install a 5-element, cross-shaped acoustic array at the measurement point, based on the predetermined impact point. Align the bottom of the array parallel to the ground. The four microphones at the bottom of the array are numbered 1, 2, 3, and 4 in a clockwise direction, with the top microphone numbered 5. 1.2) Use the signal acquisition instrument to collect the five shock wave signals and five explosion wave signals of the acoustic array, and record the arrival time t of the five shock wave signals. s and the arrival time t of the five explosion wave signals i ; 2) Signal processing 2.1) By the formula θ=θ0-θ Li +π is calculated to get the angle θ from the north; A three-dimensional coordinate system is established with the center O of the acoustic array as the origin and the directions of microphones 1, 4, and 5 as the X-axis, Y-axis, and Z-axis, respectively. The X-axis is defined as the array reference direction, and θ0 is the angle between the array reference direction and the true north direction; θ Li is the angle between the projection of the explosion wave arrival direction in the XOY plane and the X axis; 2.2) Through the formula and The average arrival time of the five shock wave signals is calculated separately and the average arrival time of the explosion wave signal The distance d from the impact point to the acoustic array, the projectile velocity v, and the explosion time t are calculated using the following formula: c is the propagation rate of the acoustic signal; is the angle between the shock wave arrival direction and the XOY plane; is the angle between the explosion wave arrival direction and the XOY plane; 2.3) The impact point position is obtained using θ, the distance d from the impact point to the acoustic array, and the position of the acoustic array itself in the geodetic coordinate system.

2. The method for obtaining terminal parameters of a supersonic projectile using a single array according to claim 1, characterized in that: In step 2.1), θ Li Calculated by the following formula: θ Li =atan2(k iy ,k ix ) in, is the blast wave vector where the blast wave arrives, The direction of the explosion wave is the direction of arrival, and the direction of the impact point relative to the measuring point is 3. The method for obtaining terminal parameters of a supersonic projectile using a single array according to claim 2, characterized in that: In step 2.1), the The method for obtaining the delay is as follows: the five explosion wave signals of microphones 1, 2, 3, 4 and 5 are cross-correlated and time delay estimation is performed in pairs, and the delay estimation value sequence τ = [τ 12 , τ 13 , τ 14 , τ 15 , τ 23 , τ 24 , τ 25 , τ 34 , τ 35 , τ 45 ] T , where the superscript T represents the transpose of the vector; the five microphone positions are paired in pairs to obtain 10 direction vectors, which can be expressed as a matrix R = [r 12 ,r 13 ,r 14 ,r 15 ,r 23 ,r 24 ,r 25 ,r 34 ,r 35 ,r 45 ], where r 12 is the vector from microphone 1 to microphone 2, and so on; The explosion wave vector is obtained by the following formula 4. A method for obtaining terminal parameters of a supersonic projectile using a single array according to claim 1, 2 or 3, characterized in that: In step 1, the radius of the acoustic array is greater than or equal to 0.7 m.

5. The method for obtaining terminal parameters of a supersonic projectile using a single array according to claim 4, characterized in that: In step 1, the distance between the measuring point and the impact point is greater than 750m.

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