Ground ammunition terminal falling angle accurate measurement method considering ammunition body rotation

Abstract

The invention belongs to the technical field of weapon ammunition test, and particularly relates to a to-ground ammunition terminal falling angle accurate measurement method considering ammunition body rotation, and the method comprises the steps: 1, carrying out the accurate distance measurement based on an orthogonal image; and 2, accurate angle measurement based on an orthogonal image. The method has the prominent advantages that new measuring equipment is not introduced under the existing test condition, the actual falling angle of the weapon is accurately obtained by reasonably arranging the existing measuring equipment and combining a mathematical method, so that the evaluation, testing and the like related to the falling angle are more scientific and accurate compared with the existing method, and the scientificity and the normalization of test data statistics are improved. Compared with an existing falling angle measuring method without considering the rotation of the projectile body, in the falling angle measuring process, the rotation of the projectile body in all directions of the space is fully considered, finally, the actual space falling angle of the weapon is determined through an orthogonalization method, a standardized measuring formula is formed, and the falling angle performance of the ammunition is scientifically evaluated conveniently.

Description

Technical Field

[0001] The invention belongs to the technical field of weapon and ammunition testing, and in particular relates to a method for accurately measuring the terminal impact angle of ground-to-ground ammunition taking into account the rotation of the projectile. Background Art

[0002] In the evaluation of ammunition strike capability, impact angle performance is one of the most commonly scored criteria. The terminal impact angle of an ammunition can be determined using the missile's attitude data, measured by the inertial navigation terminal, transmitted via telemetry data on board the missile. However, due to the lack of credibility of the data used by the participating parties in competitive bidding, independent third-party measurements under the same conditions are required for evaluation. High-speed video recorders are typically used for interpretation, and the terminal impact angle data is obtained by analyzing the relative attitude of the missile body to the local horizontal plane at the final moment.

[0003] In existing comparative measurements, a high-speed video camera positioned at a fixed angle is typically used as a benchmark for determining the angle of impact. This method generally provides relatively accurate results. However, this method ignores the projectile's rotation in space. Specifically, a high-speed video camera positioned in a specific direction cannot reflect the projectile's rotation within the camera's depth of field in a two-dimensional image. This results in somewhat approximate measurement results, failing to accurately reflect the angle of impact.

[0004] In response to the above problems, the present invention proposes a method for accurately determining the landing angle using two orthogonally arranged images taking into account the rotation of the projectile. This method can effectively enhance the accuracy of landing angle measurement in activities such as bidding and performance verification, and provide a more accurate basis for subsequent evaluation or solution improvement. Summary of the Invention

[0005] (1) Technical issues to be resolved

[0006] The technical problem to be solved by the present invention is: how to solve the problem of accurate measurement of the terminal landing angle of ground-to-ground ammunition under three-dimensional spatial rotation on the basis of existing landing area test equipment without adding new measurement equipment.

[0007] (2) Technical solution

[0008] To solve the above technical problems, the present invention provides a method for accurately measuring the terminal impact angle of ground-to-ground ammunition, taking into account the rotation of the projectile body. In the method, two identical high-speed video recorders are arranged horizontally and orthogonally with the target red flag as the center in the impact area. The two recorders use the same trigger switch to ensure measurement synchronization.

[0009] Then, two high-speed video recorders were used to obtain images of the ammunition touching the ground at the same moment, and the image parameters of the projectile in the images were measured to calculate the precise landing angle.

[0010] The method comprises:

[0011] Step 1: Accurate distance measurement based on orthogonal images;

[0012] Step 2: Accurate angle measurement based on orthogonal images.

[0013] Wherein, in said step 1, accurate distance measurement based on orthogonal images;

[0014] In a two-dimensional image, the imaging of an object reflects the projection in the vertical direction, but the rotation in the depth direction cannot be reflected. Therefore, two high-speed video recorders arranged orthogonally are combined to determine the relative position of the target in the vertical direction.

[0015] The actual height h of the target red flag is known, and the height h1 of the target red flag in the image is measured in the image later. The scaling ratio of the current imaging direction is defined as k = h / h1;

[0016] Measure the distance Δd between the vertical plane where the target red flag is located and the vertical plane where the impact point is located in the image;

[0017] The actual distance between the two vertical planes corresponding to the measurable distance Δd is:

[0018] d=kΔd (1)

[0019] The two vertical planes are: in the image captured by the high-speed video recorder, the vertical plane containing the impact point and the vertical plane containing the target red flag;

[0020] High-speed cameras arranged orthogonally to the field of view capture the spatial geometric position of the projectile at the end of the trajectory, thereby solving the landing point deviation relative to the target red flag.

[0021] In step 1, the specific process for obtaining the impact point deviation relative to the target red flag is as follows: using the target red flag as the center of the field of view of each of the two high-speed video cameras, taking images captured by the first and second high-speed video cameras at the same time, determining the impact point in each current image in high-definition magnification mode, and then measuring the distance between the impact point and the target red flag along the local horizontal line. The first high-speed video camera can determine a first distance Δx from a first vertical line at the impact point to the center line of the field of view; the second high-speed video camera can determine a second distance Δy from a second vertical line at the impact point to the center line of the field of view. Since the center lines of the fields of view of the two high-speed video cameras are orthogonal, the impact point deviation relative to the target red flag at this time is expressed as a distance Δs as follows:

[0022]

[0023] Where: k1 is the image zoom ratio of the first high-speed video recorder at the measurement moment, and k2 is the image zoom ratio of the second high-speed video recorder at the same moment.

[0024] In step 1, the distance Δs between the impact point and the target red flag reflects the distance between the impact point and the reference point. To ensure measurement accuracy, multiple pairs of high-speed video cameras should be orthogonally arranged for measurement, and the average value of the impact point distances is finally taken as the basis for assessing the final impact point accuracy.

[0025] Wherein, in said step 2, accurate angle measurement is based on orthogonal images;

[0026] With the target red flag as the center of their respective fields of view, two sets of high-speed video cameras are arranged horizontally and orthogonally. When the projectile rotates in space, the images in the first and second high-speed video cameras are different. The projectile's falling angles observed by the two cameras are θ1 and θ2 respectively, which cannot reflect the actual falling angle of the projectile.

[0027] When the projectile's rotation angle in space is not large, one of θ1 and θ2 approaches zero, and the other approaches the true landing angle θ. f However, when the three-dimensional rotation of the projectile increases, θ1 and θ2 have certain values. At this time, it is inaccurate to use any high-speed video camera image to interpret the landing angle. To ensure accurate measurement, a more general terminal landing angle measurement method is proposed here.

[0028] According to the method in step 1, the actual distance information corresponding to the projection of the center points of the warhead and tail on the ground is determined based on the orthogonal images. The specific execution process is as follows: the observation quantities Δx1 and Δx2 are obtained in the first high-speed video camera screen, which reflect the relative distance between the ground projection of the center points of the warhead and tail and the target red flag in the screen of the first high-speed video camera at the measurement moment; the observation quantities Δy1 and Δy2 are obtained in the screen of the second high-speed video camera at the same moment, which reflect the relative distance between the ground projection of the center points of the warhead and tail and the target red flag in the screen of the second high-speed video camera at the same moment; given the actual length of the target red flag, the image zoom ratios k1 and k2 of the two sets of high-speed video cameras can be determined based on the measured lengths of the target red flag in the two screens; according to the orthogonal relationship, the distance s0 of the actual projection point of the warhead on the ground relative to the bottom of the target red flag is:

[0029]

[0030] Similarly, the distance s between the center point of the projectile tail and the bottom of the target red flag is f for:

[0031]

[0032] Based on this, the true projection length L2 of the projectile on the ground can be obtained:

[0033]

[0034] Take the actual projectile length as L1, the terminal actual landing angle θ fIt can be obtained by the following formula:

[0035]

[0036] Formula (6) corresponds to the method for determining the true angle of impact of the projectile. Under the condition of orthogonally arranging two high-speed video recorders that are triggered simultaneously, it is only necessary to determine the scaling ratios k1 and k2 of the first and second high-speed video recorders, and the distances Δx1, Δx2, Δy1, and Δy2 between the projected ground distances of the projectile head and tail and the target red flag determined based on the images of the projectile in the two sets of high-speed video recorders at the same time, to accurately obtain the terminal impact angle of the ammunition. The method is simple in on-site deployment and calculation process and is suitable for popularization and use.

[0037] When considering further improving the measurement accuracy, multiple groups of measurement equipment can be arranged in pairs orthogonally. The average value of the angle of impact measurement results of each group can be taken according to the above principle, thereby further reducing the measurement error. Compared with the existing single-image angle of impact measurement, the described method can more accurately reflect the angle of impact measurement error caused by the rotation of the projectile in three-dimensional space, and has good feasibility and engineering application value.

[0038] (3) Beneficial effects

[0039] Compared with the existing angle of impact measurement method, the orthogonal image-based measurement method of the present invention can fully reflect the rotation of the projectile in three-dimensional space, reduce measurement errors, and provide more accurate and convincing measurement results for ammunition development units or bidding organizers.

[0040] This method is simple to implement and has rigorous mathematical principles. It can improve the measurement accuracy of ammunition drop angle without introducing new measurement equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 Schematic diagram of the principle of measuring the distance between objects in an image;

[0042] Figure 2 Schematic diagram of a method for determining the position of a projectile within an image;

[0043] Figure 3 Schematic diagram of the principle of accurate landing angle measurement considering the rotation of the projectile;

[0044] Figure 4 Schematic diagram of the projectile posture and observed quantities △x1 and △x2 in the picture at the moment of measurement by the first high-speed video recorder.

[0045] Figure 5 Schematic diagram of the projectile posture and observed quantities △y1 and △y2 in the picture at the moment of measurement by high-speed video recorder 2. DETAILED DESCRIPTION

[0046] In order to make the purpose, content, and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below with reference to the accompanying drawings and examples.

[0047] The present invention provides a method for accurately measuring the terminal angle of impact of ground-to-ground ammunition, taking into account the rotation of the projectile. The method is based on orthogonal images and fully considers the spatial rotation of the projectile. The method also provides an orthogonal arrangement of test field measurement equipment and data processing method that takes into account the rotation of the projectile. The method does not introduce additional measurement equipment, fully considers the characteristics of the projectile rotation in the image, and uses mathematical methods to obtain the precise angle of impact of the projectile, which is conducive to more accurate evaluation of the angle of impact performance of the ammunition.

[0048] To solve the problems of the prior art, the present invention provides a method for accurately measuring the terminal impact angle of ground-to-ground ammunition, taking into account the rotation of the projectile body. In the method, two identical high-speed video recorders are arranged horizontally and orthogonally with the target red flag as the center in the impact area. The two recorders use the same trigger switch to ensure measurement synchronization.

[0049] Then, two high-speed video recorders were used to obtain images of the ammunition touching the ground at the same moment, and the image parameters of the projectile in the images were measured to calculate the precise landing angle.

[0050] The method comprises:

[0051] Step 1: Accurate distance measurement based on orthogonal images;

[0052] Step 2: Accurate angle measurement based on orthogonal images.

[0053] Wherein, in said step 1, accurate distance measurement based on orthogonal images;

[0054] Using a high-speed video recorder image post-processing method, it is necessary to measure relevant parameters from the image and convert them into actual lengths. At this time, the scale ratio of the reference object is required as a conversion condition. The target red flag is a relatively obvious target and can be used to determine the scale ratio of the length in the vertical plane where the target red flag is located.

[0055] In a two-dimensional image, the imaging of an object reflects the projection in the vertical direction, but the rotation in the depth direction cannot be reflected. Therefore, two high-speed video recorders arranged orthogonally are combined to determine the relative position of the target in the vertical direction, such as Figure 1 As shown;

[0056] The actual height h of the target red flag is known, and the height h1 of the target red flag in the image is measured in the image later. The scaling ratio of the current imaging direction is defined as k = h / h1;

[0057] Measure the distance Δd between the vertical plane where the target red flag is located and the vertical plane where the impact point is located in the image;

[0058] The actual distance between the two vertical planes corresponding to the measurable distance Δd is:

[0059] d=kΔd (1)

[0060] The two vertical planes are: in the image captured by the high-speed video recorder, the vertical plane containing the impact point and the vertical plane containing the target red flag;

[0061] High-speed cameras arranged orthogonally to the field of view capture the spatial geometric position of the projectile at the end of the trajectory, thereby solving the landing point deviation relative to the target red flag. The specific measurement process is as follows: Figure 2 As shown;

[0062] The specific process of obtaining the landing point deviation relative to the target red flag in step 1 is as follows: taking the target red flag as the center of the field of view of each of the two high-speed video recorders, taking the images captured by the first high-speed video recorder and the second high-speed video recorder at the same time point, respectively determining the impact point in the current image in high-definition magnification mode, and then measuring the distance between the impact point and the target red flag along the local horizontal line, such as Figure 1 As shown, the first high-speed video recorder can determine a first distance Δx between the first vertical line where the impact point is located and the center line of the field of view; the second high-speed video recorder can determine a second distance Δy between the second vertical line where the impact point is located and the center line of the field of view. Since the center lines of the fields of view of the two high-speed video recorders are arranged orthogonally, the deviation of the impact point from the target red flag at this time is expressed as a distance Δs as follows:

[0063]

[0064] Where: k1 is the image zoom ratio of the first high-speed video recorder at the measurement moment, and k2 is the image zoom ratio of the second high-speed video recorder at the same moment.

[0065] Among them, in step 1, the distance Δs between the impact point and the target red flag reflects the distance between the impact point and the reference point; to ensure measurement accuracy, multiple pairs of high-speed video cameras should be orthogonally arranged for measurement, and the average value of the impact point distances should be taken as the basis for assessing the final impact point accuracy.

[0066] Wherein, in said step 2, accurate angle measurement is based on orthogonal images;

[0067] With the target red flag as the center of their respective fields of view, two sets of high-speed video recorders are arranged horizontally and orthogonally. Figure 3 As shown, when the projectile rotates in space, the images in the first high-speed video recorder and the second high-speed video recorder are different. The projectile posture in the image at the moment of measurement by the first high-speed video recorder is as follows: Figure 4 As shown, the second high-speed video recorder shows the projectile posture at the same moment. Figure 5 As shown in the figure, the projectile falling angles observed by the two are θ1 and θ2 respectively, neither of which can reflect the actual projectile falling angle;

[0068] When the projectile's rotation angle in space is not large, one of θ1 and θ2 approaches zero, and the other approaches the true landing angle θ. f However, when the three-dimensional rotation of the projectile increases, θ1 and θ2 have certain values. At this time, it is inaccurate to use any high-speed video camera image to interpret the landing angle. To ensure accurate measurement, a more general terminal landing angle measurement method is proposed here.

[0069] According to the method in step 1, the actual distance information corresponding to the projection of the center points of the warhead and tail on the ground is determined based on the orthogonal images. The specific execution process is as follows: the observation quantities Δx1 and Δx2 are obtained in the first high-speed video camera screen, which reflect the relative distance between the ground projection of the center points of the warhead and tail and the target red flag in the screen of the first high-speed video camera at the measurement moment; the observation quantities Δy1 and Δy2 are obtained in the screen of the second high-speed video camera at the same moment, which reflect the relative distance between the ground projection of the center points of the warhead and tail and the target red flag in the screen of the second high-speed video camera at the same moment; given the actual length of the target red flag, the image zoom ratios k1 and k2 of the two sets of high-speed video cameras can be determined based on the measured lengths of the target red flag in the two screens; according to the orthogonal relationship, the distance s0 of the actual projection point of the warhead on the ground relative to the bottom of the target red flag is:

[0070]

[0071] Similarly, the distance s between the center point of the projectile tail and the bottom of the target red flag is f for:

[0072]

[0073] Based on this, the true projection length L2 of the projectile on the ground can be obtained:

[0074]

[0075] Take the actual projectile length as L1, the terminal actual landing angle θ f It can be obtained by the following formula:

[0076]

[0077] Among them, formula (6) corresponds to the method for determining the true landing angle of the projectile. Under the condition of orthogonally arranging two high-speed video recorders that are triggered simultaneously, it is only necessary to determine the scaling ratios k1 and k2 of the first and second high-speed video recorders, and the distances Δx1, Δx2, Δy1, and Δy2 between the projectile head and tail on the ground and the target red flag determined based on the projectile in the two sets of high-speed video recorder images at the same time, to accurately obtain the terminal landing angle of the ammunition.

[0078] The method has simple on-site deployment and calculation processes and is suitable for popularization and use.

[0079] Among them, when considering further improving the measurement accuracy, multiple groups of measuring equipment can be arranged in pairs orthogonal to each other, and the average value of each group of landing angle measurement results can be taken according to the above principle, thereby further reducing the measurement error.

[0080] Among them, compared with the existing single-image angle measurement, the method can more accurately reflect the angle measurement error caused by the rotation of the projectile in three-dimensional space, and has good feasibility and engineering application value.

[0081] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for accurately measuring the terminal impact angle of ground-to-ground ammunition taking into account the rotation of the projectile, characterized in that: The method comprises arranging two identical high-speed video recorders horizontally and orthogonally in the landing area with the target red flag as the center, and using the same trigger switch to ensure measurement synchronization; Then, two high-speed video recorders were used to obtain images of the ammunition touching the ground at the same moment, and the image parameters of the projectile in the images were measured to calculate the precise landing angle.

2. The method for accurately measuring the terminal impact angle of ground-to-ground ammunition taking into account the rotation of the projectile as claimed in claim 1, characterized in that: The method comprises: Step 1: Accurate distance measurement based on orthogonal images; Step 2: Accurate angle measurement based on orthogonal images.

3. The method for accurately measuring the terminal impact angle of ground-to-ground ammunition taking into account the rotation of the projectile as claimed in claim 2, characterized in that: In the step 1, accurate distance measurement based on orthogonal images; In a two-dimensional image, the imaging of an object reflects the projection in the vertical direction, but the rotation in the depth direction cannot be reflected. Therefore, two high-speed video recorders arranged orthogonally are combined to determine the relative position of the target in the vertical direction. The actual height h of the target red flag is known, and the height h1 of the target red flag in the image is measured in the image later. The scaling ratio of the current imaging direction is defined as k = h / h1; Measure the distance Δd between the vertical plane where the target red flag is located and the vertical plane where the impact point is located in the image; The actual distance between the two vertical planes corresponding to the measurable distance Δd is: d=kΔd (1) The two vertical planes are: in the image captured by the high-speed video recorder, the vertical plane containing the impact point and the vertical plane containing the target red flag; High-speed cameras arranged orthogonally to the field of view capture the spatial geometric position of the projectile at the end of the trajectory, thereby solving the landing point deviation relative to the target red flag.

4. The method for accurately measuring the terminal impact angle of ground-to-ground ammunition taking into account the rotation of the projectile as claimed in claim 3, characterized in that: In step 1, the specific process of obtaining the landing point deviation relative to the target red flag is as follows: with the target red flag as the center of the field of view of each of the two high-speed video cameras, images captured by the first and second high-speed video cameras at the same time are obtained, and the impact point in the current image is determined in high-definition magnification mode. Then, the distance between the impact point and the target red flag is measured along the local horizontal line. The first high-speed video camera can determine a first distance Δx from a first vertical line at the impact point to the center line of the field of view; the second high-speed video camera can determine a second distance Δy from a second vertical line at the impact point to the center line of the field of view. Since the center lines of the fields of view of the two high-speed video cameras are orthogonal, the landing point deviation of the impact point relative to the target red flag is expressed as a distance Δs as follows: Where: k1 is the image zoom ratio of the first high-speed video recorder at the measurement moment, and k2 is the image zoom ratio of the second high-speed video recorder at the same moment.

5. The method for accurately measuring the terminal impact angle of ground-to-ground ammunition taking into account the rotation of the projectile as claimed in claim 4, characterized in that: In step 1, the distance Δs between the impact point and the target red flag reflects the distance between the impact point and the reference point. To ensure measurement accuracy, multiple pairs of high-speed video cameras should be orthogonally arranged for measurement, and the average value of the impact point distances is finally taken as the basis for assessing the final impact point accuracy.

6. The method for accurately measuring the terminal impact angle of ground-to-ground ammunition taking into account the rotation of the projectile as claimed in claim 4, characterized in that: In the step 2, accurate angle measurement based on orthogonal images; With the target red flag as the center of their respective fields of view, two sets of high-speed video cameras are arranged horizontally and orthogonally. When the projectile rotates in space, the images in the first and second high-speed video cameras are different. The projectile's falling angles observed by the two cameras are θ1 and θ2 respectively, which cannot reflect the actual falling angle of the projectile. When the projectile's rotation angle in space is not large, one of θ1 and θ2 approaches zero, and the other approaches the true landing angle θ. f However, when the three-dimensional rotation of the projectile increases, θ1 and θ2 have certain values. At this time, it is inaccurate to use any high-speed video camera image to interpret the landing angle. To ensure accurate measurement, a more general terminal landing angle measurement method is proposed here. According to the method in step 1, the actual distance information corresponding to the projection of the center points of the warhead and tail on the ground is determined based on the orthogonal images. The specific execution process is as follows: the observation quantities Δx1 and Δx2 are obtained in the first high-speed video camera screen, which reflect the relative distance between the ground projection of the center points of the warhead and tail and the target red flag in the screen of the first high-speed video camera at the measurement moment; the observation quantities Δy1 and Δy2 are obtained in the screen of the second high-speed video camera at the same moment, which reflect the relative distance between the ground projection of the center points of the warhead and tail and the target red flag in the screen of the second high-speed video camera at the same moment; given the actual length of the target red flag, the image zoom ratios k1 and k2 of the two sets of high-speed video cameras can be determined based on the measured lengths of the target red flag in the two screens; according to the orthogonal relationship, the distance s0 of the actual projection point of the warhead on the ground relative to the bottom of the target red flag is: Similarly, the distance s between the center point of the projectile tail and the bottom of the target red flag is f for: Based on this, the true projection length L2 of the projectile on the ground can be obtained: Take the actual projectile length as L1, the terminal actual landing angle θ f It can be obtained by the following formula:

7. The method for accurately measuring the terminal impact angle of ground-to-ground ammunition taking into account the rotation of the projectile as claimed in claim 6, characterized in that: Formula (6) corresponds to the method for determining the true angle of impact of the projectile. Under the condition of orthogonally arranging two high-speed video recorders that are triggered simultaneously, it is only necessary to determine the scaling ratios k1 and k2 of the first and second high-speed video recorders, and the distances Δx1, Δx2, Δy1, and Δy2 between the projectile head and tail on the ground and the target red flag determined based on the projectile in the two sets of high-speed video recorder images at the same time, to accurately obtain the terminal impact angle of the ammunition.

8. The method for accurately measuring the terminal impact angle of ground-to-ground ammunition taking into account the rotation of the projectile as claimed in claim 7, characterized in that: The method has simple on-site arrangement and calculation process and is suitable for popularization and use.

9. The method for accurately measuring the terminal impact angle of ground-to-ground ammunition taking into account the rotation of the projectile as claimed in claim 8, characterized in that: When considering further improving the measurement accuracy, multiple groups of measuring equipment can be arranged in pairs orthogonally, and the average value of each group of landing angle measurement results can be taken according to the above principle, thereby further reducing the measurement error.

10. The method for accurately measuring the terminal impact angle of ground-to-ground ammunition taking into account the rotation of the projectile as claimed in claim 9, characterized in that: Compared with the existing single-image angle of fall measurement, the method can more accurately reflect the angle of fall measurement error caused by the rotation of the projectile in three-dimensional space, and has good feasibility and engineering application value.

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