A method and system for locating impact points at sea

Abstract

This invention discloses a method and system for locating projectile impact points at sea. It involves deploying multiple floating acoustic receiving modules to acquire the acoustic signals generated by the explosion of ammunition at the impact point; acquiring the position information of the multiple acoustic receiving modules; and calculating the position of the impact point based on the acoustic signals received by the acoustic receiving modules and their position information. This invention improves upon traditional three-element array positioning by employing a cross-shaped array composed of multiple intersecting three-element arrays with a shared central element. Combined with BeiDou high-precision positioning technology, it solves the problems of inaccurate positioning and limited applicability when using traditional three-element arrays to determine projectile impact points. This improves the accuracy of projectile impact point positioning at sea and the precision of shell detection and positioning, while significantly reducing training costs.

Description

Technical Field

[0001] This invention relates to the field of acoustic positioning and measurement, and in particular to a method and system for locating impact points at sea. Background Technology

[0002] With the development of science and technology, naval gun technology has also advanced rapidly. In modern warfare, naval guns play an increasingly important role. Newly developed weapons must undergo rigorous and detailed performance tests and assessments under near-real combat conditions before being officially deployed to the armed forces, with naval gun firing accuracy being a crucial assessment criterion. Analysis of shell impact effects provides tactical guidance for subsequent combat and exercises. Accurate measurement and positioning of the impact point at sea is a prerequisite for correctly evaluating shell accuracy and density, a vital step in assessing shell impact precision, and provides valuable information and necessary support for weapon production and development. Currently, sea impact point measurement typically uses photoelectric theodolites. This positioning method, based on photoelectric positioning principles, is significantly affected by low visibility and other natural weather conditions at sea, and is also costly. Given the increasingly prominent need for assessing shell impact precision, there is an urgent need to research and develop an efficient, stable, and low-cost sea impact point positioning system and method to accurately locate the shell impact point and provide a basis for evaluating shell impact precision. Summary of the Invention

[0003] The purpose of this invention is to provide a highly efficient, stable, and low-cost method and system for locating the impact point of artillery shells at sea, accurately locating the impact point of artillery shells, and evaluating the accuracy of artillery shell strikes.

[0004] On the one hand, the present invention provides a method for locating the impact point at sea, comprising the following steps:

[0005] Multiple acoustic receiving modules floating on the sea surface are deployed to acquire the acoustic signals generated by the explosion of munitions at the point of impact. Each acoustic receiving module includes a first three-element array and a second three-element array arranged in a cross shape with a shared central array element. The first three-element array further includes a first array element and a second array element located equidistantly on both sides of the central array element. The second three-element array further includes a third array element and a fourth array element located equidistantly on both sides of the central array element. Each of the first array element, the second array element, the third array element, the fourth array element, and the central array element is equipped with a hydrophone.

[0006] Obtain the position information of multiple acoustic wave receiving modules;

[0007] The position of the impact point is calculated based on the acoustic signal received by the acoustic receiving module and the position information of the acoustic receiving module.

[0008] Preferably, the step of the sound wave receiving module acquiring the acoustic signal generated by the explosion of the ammunition at the point of impact on the sea surface includes:

[0009] The time delay difference between the first array element, the second array element, the third array element, the fourth array element and the central array element received the acoustic signal is obtained.

[0010] Preferably, the step of obtaining the location information of the acoustic wave receiving module includes:

[0011] S101: A Beidou positioning module is provided at each of the two array elements at both ends of any of the three-element arrays in the acoustic wave receiving module.

[0012] S102: Control the BeiDou positioning module to communicate with the base station and BeiDou satellites respectively to determine the position coordinates of the BeiDou positioning module;

[0013] S103: Calculate the position coordinates of the central element of the three-element array where the BeiDou positioning module is located, and the deflection angle of the baseline connecting two BeiDou positioning modules on the same three-element array relative to the first direction.

[0014] Preferably, the step of calculating the location of the bullet's impact point includes:

[0015] S201: Calculate the final azimuth angle of the impact point relative to any of the aforementioned acoustic wave receiving modules;

[0016] S202: Calculate the position coordinates of the impact point based on the position coordinates, deflection angle, and final azimuth angle of the central array element of the acoustic wave receiving module;

[0017] Step S201 includes the following steps:

[0018] S2011: Calculate the first time delay difference between the first and second elements of the first ternary array when the acoustic signal arrives, and the second time delay difference between the third and fourth elements of the second ternary array when the acoustic signal arrives.

[0019] S2012: Compare the magnitudes of the first delay difference and the second delay difference, and determine the ternary array corresponding to the smaller one as the working ternary array;

[0020] S2013: Calculate the angle between the point of impact and the direction of the line connecting the elements of the working three-element array as the final azimuth angle.

[0021] Preferably, the formula for calculating the final azimuth angle is:

[0022]

[0023] Where, τ 12τ is the time delay difference between the arrival of the acoustic signal at one end of the array element and the center array element in the working three-element array. 23 d is the time delay difference between the acoustic signal arriving at the central element and the element at the other end of the working three-element array, d is the distance between two adjacent elements, and c is the underwater propagation speed of the acoustic signal.

[0024] Preferably, the position coordinates of the impact point are as follows:

[0025]

[0026] in,

[0027] R0 is the distance between the central array element of the first acoustic receiving module and the central array element of the second acoustic receiving module.

[0028] σ is the angle formed by the lines connecting the central element of the first acoustic wave receiving module to the central element of the second acoustic wave receiving module and the point of impact.

[0029] ω is the angle formed by the lines connecting the central element of the second acoustic receiving module to the central element of the first acoustic receiving module and the point of impact.

[0030] x′ is the abscissa value of the center array element of the first acoustic wave receiving module in the two acoustic wave receiving modules.

[0031] y′ is the ordinate value of the central array element of the first acoustic wave receiving module in the two acoustic wave receiving modules.

[0032] β is the angle between the line connecting the center element of the first acoustic receiving module and the center element of the second acoustic receiving module and the second direction.

[0033] The first direction and the positive direction of the vertical axis are both due north, and the second direction and the positive direction of the horizontal axis are both due east.

[0034] Preferably, the acoustic signal acquired by the acoustic receiving module is preprocessed and then transmitted to the data processing and display control center along with the position information of the acoustic receiving module. The data processing and display control center calculates the position of the impact point.

[0035] The preprocessing includes extracting the target acoustic signal using a variable amplification method and a graded filtering method, and converting the target acoustic signal into a digital signal through an A / D converter;

[0036] The preprocessing includes filtering the signal.

[0037] Preferably, the step of calculating the position of the impact point further includes:

[0038] Based on the preset target center position information and the calculated position coordinates of the impact point, the polar coordinates of the impact point relative to the target center are calculated.

[0039] On the other hand, the present invention also provides a marine impact point positioning system, comprising:

[0040] Multiple acoustic receiving modules are used to acquire the acoustic signals generated by the explosion of the ammunition at the point of impact;

[0041] The Beidou positioning device is used to obtain the location information of the acoustic wave receiving module;

[0042] The data processing and display control center is used to receive and process acoustic signals and position information from the acoustic wave receiving module to determine the location of the impact point.

[0043] The data transmission module is used to enable data transmission between the acoustic wave receiving module, the Beidou positioning module, and the data processing and display control center.

[0044] The acoustic wave receiving module includes a first three-element array and a second three-element array arranged in a cross shape and shared by the central array elements; the first three-element array also includes a first array element and a second array element located at both ends of a straight line segment with the central array element as the midpoint; the second three-element array also includes a third array element and a fourth array element located at both ends of a straight line segment with the central array element as the midpoint; the first array element, the second array element, the third array element, the fourth array element, and the central array element are all equipped with hydrophones.

[0045] Preferably, the BeiDou positioning device includes a BeiDou positioning module deployed on the acoustic wave receiving module, and a BeiDou satellite constellation and reference station connected to the BeiDou positioning module via differential signal communication. The BeiDou positioning module is located at the array elements at both ends of any of the three-element arrays in the acoustic wave receiving module.

[0046] The beneficial effects of this invention are as follows: Firstly, the acoustic receiving module with a cross-shaped double three-element array is an optimization and improvement based on the single three-element array. When using a three-element array for positioning, the target's azimuth is only considered within the effective observation range when it is between 30° and 150°. The cross-shaped array arrangement breaks the limitation of the three-element array's direction-finding range and also solves the problem of unclear target "port and starboard" alignment. Secondly, by setting up multiple acoustic receiving modules with cross-shaped double three-element arrays and employing the azimuth-crossing positioning principle, positioning accuracy is improved. This invention solves the problems of inaccurate positioning and limited applicability of traditional three-element array positioning methods, improving the accuracy of shell impact point positioning at sea. Compared to existing technologies, this invention is low-cost, easy to operate, and highly reliable, improving shell detection and positioning accuracy while significantly reducing training costs. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of the existing three-element array positioning method;

[0048] Figure 2 This is a schematic diagram of the marine impact point positioning method and system involved in the embodiments of the present invention;

[0049] Figure 3 This is a flowchart of a method for locating the point of impact at sea according to the present invention;

[0050] Figure 4 This is a schematic diagram illustrating the steps for obtaining the location information of the acoustic positioning module according to an embodiment of the present invention;

[0051] Figure 5 This is a schematic diagram of the deflection angle involved in an embodiment of the present invention;

[0052] Figure 6 This is a schematic diagram of the final azimuth angle step involved in an embodiment of the present invention;

[0053] Figure 7 This is a schematic diagram of the rectangular coordinates of the impact point position according to an embodiment of the present invention;

[0054] Figure 8 This is a schematic diagram of the polar coordinates of the impact point position according to an embodiment of the present invention;

[0055] Figure 9 This is a flowchart of the acoustic signal processing involved in an embodiment of the present invention.

[0056] In the diagram: d - element spacing, H1 - first end element, H3 - second end element, H2 - center element, S - impact point, Q1, Q2, Q3 - acoustic receiving modules, R1 - first distance, R2 - second distance, R3 - third distance, R4 - fourth distance, R5 - fifth distance, A - first BeiDou positioning module, B - second BeiDou positioning module, M - center element of the first acoustic positioning module, N - center element of the second acoustic positioning module, R0 - center distance, P - target center, X - horizontal axis, Y - vertical axis. Detailed Implementation

[0057] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0058] like Figure 1As shown, in the traditional three-element array positioning technology, three array elements are arranged sequentially on a straight line according to the array element spacing d, namely the first array element H1 at both ends, the second array element H3 at both ends, and the central array element H2. Each array element is equipped with a sound wave receiving device. The position of the impact point S is taken as the position of the sound source. The distance from the sound source to the first array element H1 is the first distance R1, the distance from the sound source to the central array element H2 is the second distance R2, and the distance from the sound source to the second array element H3 is the third distance R3. Locating the sound source means calculating the distance and azimuth angle of the sound source relative to the central array element H2, where the second distance R2 is the target distance R that needs to be measured.

[0059] Generally, the target distance R is much larger than the element spacing d, so the actual calculated distances R1, R2, and R3 show only slight differences. This is based on the time delay τ between the received acoustic signal and the first element H1 and the center element H2. 12 And the time delay difference τ between the central array element H2 and the second end array element H3. 23 Then we can obtain the difference between the first and second distances, the difference between the second and third distances, and the azimuth angle. By taking the central array element H2 as the origin, the coordinates (x0, y0) of the sound source can be determined. It should be noted that the sound source is the point of impact of the shell on the sea surface, and the sound waves received by the three-element array are the sound waves generated by the explosion of the shell at the point of impact. The speed of sound underwater is c, and the azimuth angle is... It refers to the angle formed by the line connecting the sound source and the central array element and the horizontal coordinate axis.

[0060] In the three-element array positioning, the acoustic path difference is:

[0061]

[0062]

[0063] Through derivation, the distance and azimuth of the impact point relative to the central array element can be obtained as follows:

[0064]

[0065]

[0066] Since the target distance R is much larger than the element spacing d, the impact point can generally be considered as the far field, which allows for some simplification.

[0067] Using the expansion of a power series (keeping the quadratic terms), when |x| << 1:

[0068]

[0069] A Taylor expansion of the above sound path difference formula is performed, and the following is ignored: By squaring the above terms, we can obtain:

[0070]

[0071]

[0072] Based on the above derivation, the distance and azimuth of the impact point relative to the central array element can be obtained as follows:

[0073]

[0074]

[0075] In traditional ternary array positioning, azimuth angle The maximum range of values ​​is However, when the direction of sound propagation from the sound source to the three-element array is close to the direction between the beginning and end of the array, The value will increase dramatically, leading to a relatively large direction-finding error, only at the azimuth angle. satisfy At this time, the positioning accuracy is the best. However, the traditional three-element array floats on the sea surface and will move under the action of waves, which will change its attitude. In addition, the deviation of the shells will cause the azimuth angle to be too large or too small, which will also affect the positioning accuracy.

[0076] By taking the partial derivatives of each variable in the three-element array ranging and direction-finding formulas, the relative ranging error can be obtained. With relative direction finding error In a case study with a distance of 1000 meters from the point of impact, assuming ideal time delay estimation error and a high signal-to-noise ratio, the ranging error is several hundred meters and the direction-finding error is 10. -2 The magnitude (unit: degrees) indicates that the direction finding is relatively ideal. Therefore, the positioning method in this embodiment only utilizes the direction finding function of the three-element array in each double cross array.

[0077] One embodiment of the present invention provides a method for locating the point of impact at sea, such as... Figure 2 and Figure 3 As shown, the method includes the following steps: deploying multiple acoustic receiving modules Q1, Q2, and Q3 floating on the sea surface to acquire the acoustic signal generated by the explosion of the ammunition at the impact point S; wherein, each acoustic receiving module includes a first three-element array and a second three-element array arranged in a cross shape and sharing a central array element; the first three-element array also includes a first array element and a second array element located on both sides of the central array element and equidistant from each other; the second three-element array also includes a third array element and a fourth array element located on both sides of the central array element and equidistant from each other; the first array element, the second array element, the third array element, the fourth array element, and the central array element are all equipped with hydrophones;

[0078] Obtain the location information of multiple acoustic wave receiving modules;

[0079] The position of the impact point is calculated based on the acoustic signal received by the acoustic receiving module and the position information of the acoustic receiving module.

[0080] When a bullet explodes at its point of impact, it generates an acoustic signal. In the actual application scenario of a three-element array of sound wave receiving modules, the distance from the point of impact to the hydrophone is not much greater than the distance between the elements of the hydrophone array. Therefore, a near-field model can be adopted, in which the sound waves received by the hydrophone array are regarded as spherical waves and the sound source is regarded as a spherical sound source. The spherical sound source emits sound waves uniformly from the center of the sphere outward in the form of a sphere.

[0081] By setting up multiple acoustic receiving modules and utilizing the direction-finding function of the three-element array on any two of these modules, and employing the principle of azimuth intersection positioning, the azimuth angle of the impact point relative to these two acoustic receiving modules can be obtained. The intersection of two straight lines extending from the acoustic receiving modules along the azimuth angle indicates the location of the impact point. In this way, only the more accurate direction-finding function of the three-element array within the acoustic receiving modules is utilized, avoiding the use of the more inaccurate range-finding function, resulting in a more accurate calculated location of the impact point.

[0082] Specifically, in some embodiments, any two combinations of multiple acoustic receiving modules can calculate the location of a sound source. Therefore, multiple combinations of acoustic receiving modules can be formed to obtain the location coordinates of multiple sound sources. These multiple location coordinate results can be analyzed and processed. This not only further eliminates results with significant deviations but also performs numerical processing on the obtained location coordinates, resulting in the final determined sound source coordinates. This effectively avoids significant deviations in the positioning results due to interference from other factors during the positioning process, corrects the error range of single-point detection, and significantly improves the accuracy of shooting result evaluation.

[0083] It should be noted that in some embodiments of the present invention, only two acoustic positioning modules are used as examples for further detailed description, but the description in some embodiments should not be regarded as a limitation on the number of acoustic positioning modules of the present invention.

[0084] Furthermore, in this embodiment of the invention, any acoustic receiving module includes two ternary arrays that are cross-shaped and share a central array element. Thus, regardless of how the acoustic positioning module's orientation changes under external force, there is always one ternary array whose azimuth angle with the sound source remains constant. Within the optimal range, positioning errors caused by excessively large or small azimuth angles are effectively avoided. This invention effectively overcomes the positioning defects of traditional three-element arrays, improves positioning accuracy and stability, and has a very limited increase in cost, making it a promising candidate for industrial applications.

[0085] Although the acoustic receiving module in this embodiment of the invention is equipped with two cross-shaped three-element arrays, in actual positioning, each acoustic positioning module only uses the one with higher accuracy as the working three-element array. The angle formed by the lines connecting the sound source and the elements of the working three-element array is the final azimuth angle of the corresponding acoustic positioning module.

[0086] In some embodiments of the present invention, the step of any acoustic receiving module acquiring the acoustic signal generated by the explosion of the ammunition at the point of impact on the sea surface includes: acquiring the time delay difference between the first array element, the second array element, the third array element, and the fourth array element and the acoustic signal received by the central array element.

[0087] Since the magnitude of the time delay difference is directly related to the magnitude of the azimuth angle, the smaller the time delay difference, the larger the absolute value of the corresponding azimuth angle, and the more accurate the positioning result. In this embodiment, a three-element array with an azimuth angle in the optimal range is selected as the working three-element array based on the magnitude of the time delay difference. This ensures that the azimuth angle calculated for positioning is always within the optimal range without increasing the cost.

[0088] By calculating and comparing the time delay difference of the acoustic signals received by the array elements at both ends of the three-element array, the results are more accurate than comparing the time delay difference between the end array elements and the center array element.

[0089] In some embodiments of the present invention, such as Figure 4 As shown, the steps for obtaining the location information of any acoustic positioning module include:

[0090] S101: A Beidou positioning module is installed at each of the two array elements at either end of any three-element array in the acoustic wave receiving module.

[0091] S102: Controls the BeiDou positioning module to communicate with the base station and BeiDou satellites respectively to determine the position coordinates of the BeiDou positioning module;

[0092] S103: Calculate the position information of the central element of the three-element array where the BeiDou positioning module is located, and the deflection angle of the baseline connecting the two BeiDou positioning modules relative to the first direction.

[0093] Antennas extend from the BeiDou positioning modules located at both ends of the array element, such as... Figure 2 As shown, the four antennas on the two acoustic positioning modules constitute a rover station. The rover station works in conjunction with the BeiDou satellite and the base station to accurately determine the position coordinates of the BeiDou positioning module.

[0094] The BeiDou positioning module can be set at either end of the three-element array in the acoustic receiving module; this can be either a working or non-working three-element array. If it is set on a working three-element array, the first direction is due north. If it is set on a non-working three-element array, since the two three-element arrays are intersected at a 90-degree angle, the angle of deflection of the line connecting the two end elements of the working three-element array relative to due north can be calculated based on the deflection angle of the baseline between the BeiDou positioning modules corresponding to the first direction.

[0095] like Figure 5 As shown, taking the BeiDou positioning module set at both ends of the working three-element array as an example, a first BeiDou positioning module A is set at one end of the array, and a second BeiDou positioning module B is set at the other end. The line connecting the antennas of the two BeiDou positioning modules is called the baseline. The two antennas receive BeiDou satellite information. Through communication positioning between the BeiDou positioning module, the base station, and the BeiDou satellite, the spatial coordinates of each BeiDou positioning module can be obtained. The angle θ and elevation angle α of the baseline direction deviating from the first direction can be calculated. In this embodiment, the first direction is due north. In the local coordinate system with the antenna of the first BeiDou positioning module A as the origin, the antenna coordinates of the second BeiDou positioning module B are set as (dx, dy, dz). The deflection angle θ and elevation angle α can be calculated using the formula:

[0096]

[0097]

[0098] Since the cross array is arranged parallel to the water surface and the elevation angle α is 0°, only the angle θ between the baseline direction and true north is considered. This spatial coordinate can be converted into planar coordinates to establish a two-dimensional planar coordinate system, thereby obtaining the position coordinates of the central array element of the acoustic positioning module and the deflection angle of the working three-element array.

[0099] In some embodiments of the present invention, the step of calculating the position of the bullet's impact point includes:

[0100] S201: Calculate the final azimuth angle of the impact point relative to any of the aforementioned acoustic wave receiving modules;

[0101] S202: Calculate the position coordinates of the impact point based on the position coordinates, deflection angle, and final azimuth angle of the central array element of the acoustic wave receiving module;

[0102] In some embodiments, the steps for calculating the final azimuth angle are as follows: Figure 6 As shown, it includes:

[0103] S2011: Calculate the first time delay difference between the first and second elements of the first ternary array when the acoustic signal arrives, and the second time delay difference between the third and fourth elements of the second ternary array when the acoustic signal arrives.

[0104] S2012: Compare the magnitudes of the first delay difference and the second delay difference, and determine the ternary array corresponding to the smaller one as the working ternary array.

[0105] S2013: Calculate the angle between the point of impact and the direction of the line connecting the elements of the working three-element array as the final azimuth angle.

[0106] Preferably, the formula for calculating the final azimuth angle is:

[0107]

[0108] Where, τ 12 τ is the time delay difference between the arrival of the acoustic signal at one end of the array element and the center array element in the working three-element array. 23 d is the time delay difference between the acoustic signal arriving at the central element and the element at the other end of the working three-element array, d is the distance between two adjacent elements, and c is the underwater propagation speed of the acoustic signal.

[0109] In some embodiments of the present invention, two acoustic positioning modules are used to calculate the position coordinates of the impact point, such as... Figure 7 As shown, the positive direction of the vertical axis Y is due north, and the positive direction of the horizontal axis X is due east. In this embodiment, the first direction is due north, and the second direction is due east. The planar coordinates of the central element of the acoustic positioning module's cross array are then calculated. The planar coordinates of the central element M of the first acoustic positioning module in the coordinate system are (x′, y′), and the planar coordinates of the central element N of the second acoustic positioning module are (x″, y″). Here, the central element M of the first acoustic receiving module is also the central element of the working three-element array in the first acoustic receiving module, and the central element N of the second acoustic receiving module is also the central element of the working three-element array in the second acoustic receiving module. Through the derivation of geometric relationships, the coordinates of the impact point (x0, y0) can be obtained.

[0110] The formulas used in the derivation are as follows:

[0111]

[0112]

[0113]

[0114]

[0115]

[0116] x0 = x′ + R4cos(σ + β)

[0117] y0=y′+R4sin(σ+β)

[0118] Given the coordinates of the central array elements of the two BeiDou positioning modules, the distance R0 between the central array elements of the first and second acoustic positioning modules and the distance R4 between the sound source and the central array element of the first acoustic positioning module can be calculated.

[0119]

[0120]

[0121] And, the formula for calculating the position coordinates (x0, y0) of the impact point S is:

[0122]

[0123]

[0124] in,

[0125] R0 is the distance between the central array element M of the first acoustic wave receiving module and the central array element N of the second acoustic wave receiving module.

[0126] R4 is the distance between the central element M of the first acoustic receiving module and the point of impact.

[0127] R5 is the distance between the central element N of the second acoustic receiving module and the point of impact.

[0128] σ is the angle formed by the lines connecting the central element of the first acoustic wave receiving module to the central element of the second acoustic wave receiving module and the point of impact.

[0129] ω is the angle formed by the lines connecting the central element of the second acoustic receiving module to the central element of the first acoustic receiving module and the point of impact.

[0130] x0 is the x-coordinate of the point of impact.

[0131] y0 is the ordinate value of the point of impact.

[0132] x′ is the abscissa value of the central array element M of the first acoustic wave receiving module in the two acoustic wave receiving modules.

[0133] y′ is the ordinate value of the central array element M of the first acoustic wave receiving module in the two acoustic wave receiving modules.

[0134] θ1 is the deflection angle of the line connecting the two array elements in the working three-element array of the first acoustic wave receiving module relative to the first direction.

[0135] The final azimuth angle of the impact point relative to the central element M of the first acoustic wave receiving module is given.

[0136] θ2 is the deflection angle of the line connecting the two array elements in the working three-element array of the second acoustic wave receiving module relative to the first direction.

[0137] The final azimuth angle of the impact point relative to the central element N of the second acoustic receiving module.

[0138] β is the angle between the line connecting the central array element M of the first acoustic wave receiving module and the central array element N of the second acoustic wave receiving module and the second direction.

[0139] In some embodiments of the present invention, based on the position information of the impact point S, a polar coordinate system is established with the target center P as the origin. Using the relationship between the position of the target center P and the position of the impact point S, the polar coordinates of the impact point S relative to the target center P are obtained, such as... Figure 8 As shown, the error of the bullet impact point can be determined by the polar coordinates of the impact point S, thereby judging the accuracy of the shooting result.

[0140] The formula for calculating polar coordinates is as follows:

[0141]

[0142]

[0143] The target center P has coordinates (x, y), and the impact point S has coordinates (x0, y0).

[0144] In some embodiments of the present invention, the acoustic signal acquired by the acoustic receiving module, after preprocessing and pre-processing, is transmitted together with the position information of the acoustic receiving module to the data processing and display control center. The data processing and display control center calculates the position of the impact point, such as... Figure 9 As shown. Before the sound signal is transmitted to the data processing and display control center, it needs to undergo preprocessing. Preprocessing includes extracting the target sound signal using variable amplification and / or graded filtering, and converting it into a digital signal through A / D conversion. Preprocessing includes filtering the signal.

[0145] Because the hydrophone receives a large amount of signal information and contains a lot of redundant data, it needs to undergo some processing before being transmitted to the data processing and display control center. First, the signal undergoes preprocessing, using variable amplification and graded filtering to extract a reliable acoustic signal, which is then converted into a digital signal via A / D conversion. Second, the signal undergoes simple preprocessing, including basic filtering, to avoid overloading the processor with too much redundant data transmitted to the data processing and display control center. Signal feature analysis and comparison, target location estimation, data compression, and post-processing are all completed at the data processing and display control center. Finally, the processed acoustic signal is precisely analyzed at the data processing and display control center to determine the location of the explosion point.

[0146] Embodiments of the present invention also provide a marine impact point positioning system, comprising:

[0147] Multiple acoustic receiving modules are used to acquire the acoustic signals generated by the ammunition at the point of impact;

[0148] The Beidou positioning device is used to obtain the location information of the acoustic wave receiving module;

[0149] The data processing and display control center is used to receive and process the acoustic signals and the position information of the acoustic wave receiving module to determine the position of the impact point.

[0150] The data transmission module is used to enable data transmission between the acoustic wave receiving module, the Beidou positioning module, and the data processing and display control center.

[0151] The acoustic wave receiving module includes a first three-element array and a second three-element array arranged in a cross shape and shared by the central array elements; the first three-element array also includes a first array element and a second array element located at both ends of a straight line segment with the central array element as the midpoint; the second three-element array also includes a third array element and a fourth array element located at both ends of a straight line segment with the central array element as the midpoint; the first array element, the second array element, the third array element, the fourth array element and the central array element are all equipped with hydrophones.

[0152] The acoustic receiving module, along with a floating body, is deployed as a buoy on the sea surface near the firing range. An anchor is dropped onto the buoy to stabilize its attitude. The acoustic receiving module is used to receive the sound of exploding shells at sea. The received and extracted acoustic signals undergo preprocessing and signal preprocessing before being wirelessly transmitted to the data processing and display control center along with differential signals.

[0153] In some embodiments of the present invention, the BeiDou positioning device includes a BeiDou positioning module deployed on the acoustic wave receiving module, and a BeiDou satellite constellation and reference station connected to the BeiDou positioning module via differential signal communication. The BeiDou positioning module is located at the array elements at both ends of any three-element array in the acoustic wave receiving module.

[0154] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0155] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A method of offshore impact point location, characterized by, Includes the following steps: Multiple acoustic receiving modules floating on the sea surface are deployed to acquire the acoustic signals generated by the explosion of munitions at the point of impact. Each acoustic receiving module includes a first three-element array and a second three-element array arranged in a cross shape with a shared central array element. The first three-element array further includes a first array element and a second array element located equidistantly on both sides of the central array element. The second three-element array further includes a third array element and a fourth array element located equidistantly on both sides of the central array element. Each of the first array element, the second array element, the third array element, the fourth array element, and the central array element is equipped with a hydrophone. Obtain the position information of multiple acoustic wave receiving modules; The position of the impact point is calculated based on the acoustic signal received by the acoustic receiving module and the position information of the acoustic receiving module. The steps for obtaining the location information of the acoustic wave receiving module include: S101: A Beidou positioning module is provided at each of the two array elements at both ends of any of the three-element arrays in the acoustic wave receiving module. S102: Control the BeiDou positioning module to communicate with the base station and BeiDou satellites respectively to determine the position coordinates of the BeiDou positioning module; S103: Calculate the position coordinates of the central element of the three-element array where the BeiDou positioning module is located, and the deflection angle of the baseline connecting two BeiDou positioning modules on the same three-element array relative to the first direction; the first direction is due north. The steps for calculating the point of impact of an ammunition include: S201: Calculate the final azimuth angle of the impact point relative to any of the aforementioned acoustic wave receiving modules; S202: Calculate the position coordinates of the impact point based on the position coordinates, deflection angle, and final azimuth angle of the central array element of the acoustic wave receiving module; Step S201 includes the following steps: S2011: Calculate the first time delay difference between the first and second elements of the first ternary array when the acoustic signal arrives, and the second time delay difference between the third and fourth elements of the second ternary array when the acoustic signal arrives. S2012: Compare the magnitudes of the first delay difference and the second delay difference, and determine the ternary array corresponding to the smaller one as the working ternary array; S2013: Calculate the angle between the point of impact and the direction of the line connecting the elements of the working three-element array as the final azimuth angle; The formula for calculating the final azimuth angle is: wherein, is the time delay difference of the acoustic signal reaching the center element and the element at one end of the working three-element array, is the time delay difference of the acoustic signal reaching the center element and the element at the other end of the working three-element array, is the spacing between two adjacent elements, is the speed of underwater propagation of acoustic signals.

2. A method of locating a point of impact at sea as claimed in claim 1, characterised in that, The steps of the acoustic receiving module to acquire the acoustic signal generated by the explosion of the munition at the point of impact on the sea surface include: The time delay difference between the first array element, the second array element, the third array element, the fourth array element and the central array element received the acoustic signal is obtained.

3. A method of locating a point of impact at sea as claimed in claim 1, characterized in that, In step S202, the coordinates of the impact point are as follows: in, is the distance between the center element of the first acoustic wave receiving module and the center element of the second acoustic wave receiving module in the acoustic wave receiving module, is an angle formed by the connecting line between the center element of the first acoustic wave receiving module and the center element of the second acoustic wave receiving module and the impact point, is an angle formed by the connecting line between the center element of the second acoustic wave receiving module and the center element of the first acoustic wave receiving module and the impact point, respectively, is a horizontal coordinate value of a center element of a first sound wave receiving module of the two sound wave receiving modules, Y1 is the vertical coordinate value of the first acoustic wave receiving module, an angle between a line connecting the center element of the first acoustic wave receiving module and the center element of the second acoustic wave receiving module with respect to the second direction; The positive direction of the vertical axis is due north, the second direction is due east, and the positive direction of the horizontal axis is also due east.

4. A method of locating a point of impact at sea as claimed in claim 1, wherein, The acoustic wave receiving module transmits the acquired acoustic signal, after preprocessing and pre-processing, along with the position information of the acoustic wave receiving module, to the data processing and display control center. The data processing and display control center then calculates the position of the impact point. The pre-processing includes extracting the target sound signal by using a variable multiple amplification method and a hierarchical filtering method, and converting the target sound signal into a digital signal through A / D conversion. The pre-processing includes filtering the signal.

5. A method of locating a point of impact at sea as claimed in claim 1, wherein, The step of calculating the position of the impact point further includes: According to the preset position information of the target center and the calculated position coordinates of the impact point, the polar coordinates of the impact point relative to the target center are calculated.

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