One-dimensional error analysis method, system and device for synthetic aperture sonar imaging method

Abstract

The invention discloses a one-dimensional error analysis method, system and device for a synthetic aperture sonar imaging method, and relates to the technical field of image processing. The one-dimensional error analysis method comprises the following steps: according to the directivity functions of the transmitting and receiving array elements respectively, the joint directivity function of the transmitting and receiving array elements is calculated to determine the beam width of the sonar system; according to the farthest imaging distance and the beam width of the sonar system, the coordinates of the target to be set in the azimuth direction are calculated in the imaging area; according to the geometric relationship, the distance error between the precise instantaneous two-way slant range between different positions of the sonar azimuth direction and the target and the approximate slant range of the imaging method to be evaluated is calculated; in the imaging area, the minimum number of the target to be set and the coordinates in the range direction are determined, and the receiving array elements for the distance error to be investigated are determined; and the distance error between the precise instantaneous two-way slant range and the approximate slant range of the imaging method to be evaluated is calculated. In this way, the method can quickly evaluate the advantages and disadvantages of the sonar imaging method.

Description

Technical Field

[0001] The present invention relates to the technical field of image processing, and in particular to a one-dimensional error analysis method, system and device for a synthetic aperture sonar imaging method. Background Art

[0002] Synthetic aperture sonar relies on motion to obtain a virtual large array, which can achieve a resolution one order of magnitude higher than traditional real aperture sonar. The application of multi-receiver array technology in synthetic aperture sonar improves surveying and mapping efficiency and further promotes the practical application of synthetic aperture sonar in underwater engineering.

[0003] Synthetic aperture sonar imaging is an important part of the synthetic aperture sonar system, and is essentially the inverse process of synthetic aperture sonar data acquisition. The time domain imaging method can accurately achieve imaging through a two-dimensional space-varying filter function, but its efficiency is the lowest among all imaging algorithms, so in practice, the time domain imaging method is often not used, and the more efficient frequency domain imaging method is more often used. At present, although the multi-receiver synthetic aperture sonar effectively solves the contradiction between high resolution in azimuth and ranging in range, the two-way slant range history between the sonar and the target includes the single root distance between the transmitting array element and the target and the single root distance between the receiving array element and the target, so the phase dwell principle cannot be directly used to derive the phase dwell point and two-dimensional frequency domain system function required by the imaging algorithm. Generally speaking, in order to derive the phase dwell point and two-dimensional frequency domain system function with analytical and explicit expressions, it is necessary to perform various approximate processing on the two-way slant range history or phase dwell point or two-dimensional frequency domain system function of the multi-receiver synthetic aperture sonar. However, these approximate processing will inevitably bring errors to the synthetic aperture sonar imaging results, thereby reducing or even worsening the imaging performance. How to quickly evaluate the advantages and disadvantages of various approximate processing methods is an important part of the multi-receiver array synthetic aperture sonar imaging work.

[0004] The traditional error evaluation method needs to first assume that the error of the approximate processing can meet the imaging requirements, so as to obtain the phase residence point or two-dimensional frequency domain system function of the multi-receiving array synthetic aperture sonar, and design the corresponding imaging algorithm based on this. After processing the simulated echo or the measured data of the lake and sea test, the three quantitative indicators of the azimuth resolution, peak sidelobe ratio and integrated sidelobe ratio of the focused target are calculated to further analyze the advantages and disadvantages of the approximate processing method adopted. The whole evaluation process is long and not intuitive. Summary of the invention

[0005] In view of the problem that the distance error evaluation cycle of the traditional multi-receiving array synthetic aperture sonar is long and the efficiency is low, the present invention provides a one-dimensional error analysis method, system and device for a synthetic aperture sonar imaging method, wherein the one-dimensional error analysis method can quickly evaluate the advantages and disadvantages of the imaging method based on distance approximation, thereby guiding the design of the imaging algorithm.

[0006] In order to solve the above problems, the technical solution adopted by the present invention is: the one-dimensional error analysis method first calculates the joint directivity function of the transmitting and receiving array elements according to the directivity functions of the transmitting and receiving array elements, and then determines the beam width of the sonar system; according to the farthest imaging distance of the sonar system and the sonar beam width, the coordinates of the target to be set in the azimuth direction are calculated in the imaging area; based on the principle that the target must be within the observation angle range of the sonar beam, the distance error between the precise instantaneous two-way slant range and the approximate slant range of the imaging method to be evaluated at different positions in the sonar azimuth direction is calculated according to the geometric relationship; according to the criterion that the partial derivative of the distance error with respect to the distance is zero, the minimum number of targets to be set and their coordinates in the distance direction are determined in the imaging area; according to the criterion that the partial derivative of the distance error with respect to the spacing between the transmitting and receiving array elements is zero, the receiving array element whose distance error is to be examined is determined in the imaging area; according to the target distance and the receiving array element that have been calculated in advance, the distance error between the precise instantaneous two-way slant range and the approximate slant range of the imaging method to be evaluated is calculated. The one-dimensional error analysis method of the present invention mainly includes the following steps:

[0007] (1) Based on the directivity functions of the transmitting and receiving array elements, the joint directivity function of the transmitting and receiving array elements is calculated, thereby determining the beam width of the sonar system;

[0008] (2) Calculate the azimuth coordinates of the target to be set in the imaging area based on the maximum imaging distance and sonar beam width of the sonar system;

[0009] (3) Based on the principle that the target must be within the observation angle range of the sonar beam, the distance error between the precise instantaneous two-way slant range between the sonar position and the target and the approximate slant range of the imaging method to be evaluated is calculated according to the geometric relationship;

[0010] (5) According to the criterion that the partial derivative of the range error with respect to the distance is zero, determine the minimum number of targets to be set in the imaging area and their coordinates in the range direction;

[0011] (6) According to the criterion that the partial derivative of the distance error with respect to the spacing between the transmitting and receiving array elements is zero, determine the receiving array element whose distance error is to be investigated in the imaging area;

[0012] (7) Based on the target distance and receiving array elements calculated in advance, calculate the distance error between the precise instantaneous two-way slant range and the approximate slant range of the imaging method to be evaluated.

[0013] According to one aspect of the present invention, the present invention provides a one-dimensional error analysis method for a synthetic aperture sonar imaging method, wherein the one-dimensional error analysis method comprises the following steps:

[0014] S1, calculating the joint directivity function of the transmitting and receiving array elements according to their respective directivity functions to determine the beam width of the sonar system;

[0015] S2, calculating the coordinates of the target to be set in the azimuth direction in the imaging area according to the farthest imaging distance and beam width of the sonar system;

[0016] S3, based on the principle that the target must be within the observation angle range of the sonar beam, calculate the distance error between the precise instantaneous two-way slant range between the sonar azimuth and the target and the approximate slant range of the imaging method to be evaluated according to the geometric relationship;

[0017] S4, according to the principle that the partial derivative of the distance error with respect to the distance is zero, determining the minimum number of targets to be set in the imaging area and the coordinates in the distance direction;

[0018] S5, according to the principle that the partial derivative of the distance error with respect to the spacing between the transmitting and receiving array elements is zero, determining the receiving array element whose distance error is to be investigated in the imaging area;

[0019] S6, calculating the distance error between the precise instantaneous two-way slant range and the approximate slant range of the imaging method to be evaluated based on the target distance and receiving array elements calculated in advance.

[0020] As a further improvement of the technical solution of the present invention, in step S1, the calculation formula for calculating the joint directivity function of the transmitting and receiving array elements is: ,

[0021] in represents the directivity function of the transmitting array element, represents the directivity function of the receiving array element, Represents the directivity function of the transmitting and receiving array elements of the sonar system, Indicates the angle formed by the target sonar line of sight and the sonar positive side view direction;

[0022] For joint directivity function After normalization and logarithm processing, the formula is: , where the joint directivity function The difference between the two angle values ​​corresponding to the maximum value dropping by -3dB is the beam width of the sonar system. , Indicates maximum value processing. Indicates taking absolute value.

[0023] As a further improvement of the technical solution of the present invention, in step S2, according to the farthest imaging distance and beam width of the sonar system, the calculation formula for calculating the coordinates of the target to be set in the azimuth direction in the imaging area is: ,in It represents the synthetic aperture length corresponding to the target at the farthest distance, and its expression is ,in Indicates the distance of the target at the farthest distance, Indicates the beam width of the sonar system. The value corresponding to the azimuth coordinate of the target at the farthest distance cannot be less than , considering the non-spatial nature of the azimuth of the positive side-looking synthetic aperture sonar, the distance upward , ,……, Location The azimuth coordinates of each target are uniformly taken as: ,in Indicated in , ,……, Location The azimuth coordinates of a common target.

[0024] As a further improvement of the technical solution of the present invention, in step S3, the precise instantaneous two-way slant distance is calculated. The calculation formula is: , where the subscript Indicates The first receiving array element and the transmitting array element are composed of subsystems that satisfy , Represents the total number of receiving array elements, Represents the coordinate of the target in the range direction, Indicates the coordinates of the target in the azimuth direction, Indicates the slow time of the direction, Indicates The first receiving array element and the transmitting array element are composed of The distance between the transmitting and receiving elements in each subsystem, Indicates the speed of the sonar platform in azimuth. represents the underwater sound speed; the two-way slant range history for the imaging method to be evaluated , using the precise instantaneous two-way slant range calculated for the receiving element to be investigated Calculate the distance error between the approximate slant ranges of the imaging methods to be evaluated , and its calculation formula is: .

[0025] As a further improvement of the technical solution of the present invention, in step S4, the calculation formula for the partial derivative of the distance error with respect to the distance to be zero is: ,in represents the distance error between the precise instantaneous two-way slant range and the approximate slant range of the imaging method to be evaluated, Indicates the distance of the target in the range direction, It represents the partial derivative of the distance error with respect to the distance. A partial derivative of zero indicates the maximum or minimum value of the distance error in the distance direction. When setting the target, the closest distance, the farthest distance, the maximum distance and the minimum distance of the target are considered. Let the total number of maximum and minimum values ​​be , the total number of targets to be set is , where the distance coordinates of the nearest target are , the distance coordinate of the farthest target is , corresponding to The established distance is defined as , ,……, .

[0026] As a further improvement of the technical solution of the present invention, in step S5, the calculation formula for the partial derivative of the distance error with respect to the distance between the transmitting and receiving array elements to be zero is: ,in represents the distance error between the precise instantaneous two-way slant range and the approximate slant range of the imaging method to be evaluated, Represents the distance between the transmitting array element and the receiving array element, It represents the partial derivative of the distance error with respect to the distance between the transmitting and receiving array elements. The partial derivative of zero indicates the maximum or minimum value of the distance error in the dimension of the distance between the transmitting and receiving array elements. When setting the target, it is necessary to consider the receiving array element with the closest distance between the transmitting and receiving array elements, the receiving array element with the farthest distance between the transmitting and receiving array elements, the receiving array element corresponding to the maximum value, and the receiving array element corresponding to the minimum value. Let the total number of maximum and minimum values ​​be , the total number of receiving array elements that need to be examined is ,in Indicates the distance between the transmitting and receiving array elements when they are closest. Indicates the distance when the distance between the transmitting and receiving array elements is the farthest. The obtained transceiver array element spacing is rounded to an integer After processing, other receiving array elements that need to examine the distance error are obtained.

[0027] As a further improvement of the technical solution of the present invention, the calculation formula for calculating the distance error between the precise instantaneous two-way slant range and the approximate slant range of the imaging method to be evaluated is: ,in Indicates the slow time of the direction, Indicates the number of imaging methods to be evaluated for the space. The approximate two-way slant range history calculated for each target satisfies , Indicates the total number of targets set. Indicates the number of The precise instantaneous two-way slant range calculated for each target is calculated using the following formula: , where the subscript Indicates The first receiving array element and the transmitting array element are composed of subsystems that satisfy , Represents the total number of receiving array elements, Represents the coordinate of the target in the range direction, Indicates the coordinates of the target in the azimuth direction, Indicates the slow time of the direction, Indicates The first receiving array element and the transmitting array element are composed of The distance between the transmitting and receiving elements in each subsystem, Indicates the speed of the sonar platform in azimuth. Represents the speed of sound underwater.

[0028] According to another aspect of the present invention, the present invention further provides a one-dimensional error analysis system for a synthetic aperture sonar imaging method, comprising:

[0029] A first calculation unit is used to calculate the joint directivity function of the transmitting and receiving array elements according to the directivity functions of the transmitting and receiving array elements, so as to determine the beam width of the sonar system;

[0030] A second calculation unit is used to calculate the coordinates of the target to be set in the azimuth direction in the imaging area according to the farthest imaging distance and beam width of the sonar system;

[0031] The third calculation unit is used to calculate the distance error between the precise instantaneous two-way slant range between the sonar azimuth and the target and the approximate slant range of the imaging method to be evaluated according to the geometric relationship based on the principle that the target must be within the observation angle range of the sonar beam;

[0032] A first determining unit is used to determine the minimum number of targets to be set and their coordinates in the distance direction in the imaging area according to the principle that the partial derivative of the distance error with respect to the distance is zero;

[0033] A second determination unit is used to determine the receiving array element whose distance error is to be examined in the imaging area according to the principle that the partial derivative of the distance error with respect to the distance between the transmitting and receiving array elements is zero;

[0034] The fourth calculation unit is used to calculate the distance error between the precise instantaneous two-way slant range and the approximate slant range of the imaging method to be evaluated according to the target distance and the receiving array element calculated in advance.

[0035] As a further improvement of the technical solution of the present invention, the third calculation unit is used to calculate the precise instantaneous two-way slope distance The calculation formula is: , where the subscript Indicates The first subsystems that satisfy , Indicates the total number of receiving array elements, Indicates the coordinates of the target in the range direction, Indicates the coordinates of the target in the azimuth direction, Indicates the slow time of the direction, Indicates The first The distance between the transmitting and receiving elements in each subsystem, Indicates the speed of the sonar platform in azimuth. represents the underwater sound speed; the two-way slant range history for the imaging method to be evaluated , using the precise instantaneous two-way slant range calculated for the receiving element to be investigated Calculate the distance error between the approximate slant ranges of the imaging methods to be evaluated , and its calculation formula is: .

[0036] According to another aspect of the present invention, the present invention further provides a computing device, comprising a processor and a memory, wherein the memory stores computer program instructions, and when the computer program instructions are executed in the processor, the processor executes a one-dimensional error analysis method, wherein the one-dimensional error analysis method comprises the following steps:

[0037] According to the directivity functions of the transmitting and receiving array elements, the joint directivity function of the transmitting and receiving array elements is calculated to determine the beam width of the sonar system;

[0038] According to the farthest imaging distance and beam width of the sonar system, the coordinates of the target to be set in the azimuth direction are calculated in the imaging area;

[0039] Based on the principle that the target must be within the observation angle range of the sonar beam, the distance error between the precise instantaneous two-way slant range between the sonar position and the target and the approximate slant range of the imaging method to be evaluated is calculated according to the geometric relationship;

[0040] According to the principle that the partial derivative of the distance error with respect to the distance is zero, the minimum number of targets to be set and their coordinates in the distance direction are determined in the imaging area;

[0041] According to the principle that the partial derivative of the distance error with respect to the spacing between the transmitting and receiving array elements is zero, the receiving array element whose distance error is to be investigated is determined in the imaging area;

[0042] According to the target distance and receiving array elements calculated in advance, the distance error between the precise instantaneous two-way slant range and the approximate slant range of the imaging method to be evaluated is calculated.

[0043] Compared with the prior art, the present invention has at least the following beneficial effects:

[0044] First, the one-dimensional error analysis method of the present invention can quickly evaluate the pros and cons of the distance approximation imaging method, thereby guiding the design of the imaging algorithm;

[0045] Secondly, the one-dimensional error analysis method of the present invention does not need to complete the tedious process of imaging algorithm design, program writing, simulation imaging, etc. according to the approximate slant range history to obtain the evaluation result. Instead, the distance error can be obtained quickly and conveniently according to the approximate slant range history, and then the approximate slant range history can be judged whether it can meet the high-resolution imaging requirements according to whether the error is much smaller than the wavelength, which greatly improves the efficiency of imaging method modeling.

[0046] Other beneficial effects of the present invention will be further disclosed in the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 The figure is a flow chart of error calculation of a one-dimensional error analysis method of the present invention.

[0048] Figure 2 Two-dimensional imaging geometry for multi-subarray synthetic aperture sonar.

[0049] Figure 3 These are the two-dimensional imaging results and azimuth profiles that the traditional performance evaluation method relies on, where (a) is the imaging result of the target at a distance of 35m, (b) is the imaging result of the target at a distance of 205m, (c) is the azimuth profile after the target is focused at a distance of 35m, and (d) is the azimuth profile after the target is focused at a distance of 205m.

[0050] Figure 4 is the joint directivity function of the transmitting and receiving array elements.

[0051] Figure 5 This is an error diagram obtained based on the one-dimensional error analysis method of the present invention.

[0052] Figure 6 It is a flow chart of the one-dimensional error analysis method of the present invention.

[0053] Figure 7 It is a schematic block diagram of the one-dimensional error analysis system of the present invention.

[0054] Figure 8 It is a schematic block diagram of a computing device of the present invention.

[0055] In the figure:

[0056] 700, one-dimensional error analysis system; 710, first calculation unit; 720, second calculation unit; 730, third calculation unit; 740, first determination unit; 750, second determination unit; 760, fourth calculation unit;

[0057] 800, computing device; 810, memory; 820, processor; 830, input device; 840, output device. DETAILED DESCRIPTION

[0058] Before describing in detail any embodiment of the present invention, it should be understood that the present invention is not limited in its application to the construction and arrangement details of the components described below or illustrated in the following figures. The present invention can have other embodiments and can be practiced or carried out in various ways. In addition, it should be understood that the words and terms used here are for descriptive purposes and should not be considered restrictive. The use of "including" or "having" and its variations herein is intended to cover the items and their equivalents and additional items displayed below. Unless otherwise specified or limited, the terms "install", "connect", "support" and "couple" and their variations are widely used and cover direct installation and indirect installation, connection, support and connection. In addition, "connect" and "couple" are not limited to physical or mechanical connections or connections.

[0059] Furthermore, on the first aspect, in the disclosure of the present invention, the orientations or positional relationships indicated by terms such as “longitudinal”, “transverse”, “upper”, “lower”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside” and “outside” are based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore the above terms cannot be understood as limitations on the present invention; on the second aspect, the term “one” should be understood as “at least one” or “one or more”, that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be multiple, and the term “one” cannot be understood as a limitation on the quantity.

[0060] Attached Figure 1 The error calculation process of a one-dimensional error analysis method of the present invention is shown. Figure 2The two-dimensional imaging geometry of multi-array SAS (multi-array synthetic aperture sonar) is given, where the horizontal direction is the range direction and the vertical direction is the azimuth direction. Assume that the sonar platform speed is , the speed of sound underwater is , the transmitting signal of the transmitting array is modulated frequency Chirp signal, then The echo signal received by a receiving array element can be expressed as: ,in and They represent the fast time in distance and the slow time in azimuth respectively. Indicates the transmitted Chirp signal, is the carrier wavelength.

[0061] To consider the two-way slant distance history of the "stop-go-stop" approximation, Indicates the distance of the point target, represents the distance between the transmitting and receiving array elements, and the joint directivity function of the transmitting and receiving array elements is ignored. It indicates the distance that the receiving element moves in azimuth during the transmission and reception of signals. Indicates that the transmitting array element transmits the signal to the The precise propagation time of the signal during the process of receiving the echo by the receiving array element is expressed as:

[0062] .

[0063] According to the directivity functions of the transmitting and receiving array elements, the joint directivity function of the transmitting and receiving array elements is calculated to determine the beam width of the sonar system. The calculation formula of the joint directivity function is: ,in represents the directivity function of the transmitting array element, represents the directivity function of the receiving array element, Represents the directivity function of the transmitting and receiving array elements of the sonar system, Indicates the angle between the target sonar line of sight and the sonar's positive side view direction.

[0064] For joint directivity function After normalization and logarithm processing, the formula is: , where the joint directivity function The difference between the two angle values ​​corresponding to the maximum value dropping by -3dB is the beam width of the sonar system. , Indicates maximum value processing. Indicates taking absolute value.

[0065] According to the maximum imaging distance of the sonar system and the sonar beam width, the coordinates of the target to be set in the imaging area are calculated in the azimuth direction. The calculation formula is: ,in It represents the synthetic aperture length corresponding to the target at the farthest distance, and its expression is ,in Indicates the distance of the target at the farthest distance, represents the synthetic aperture length corresponding to the target at the farthest distance, Represents the beam width of the sonar system, so the azimuth coordinate value corresponding to the target at the farthest distance cannot be less than , considering the non-spatial nature of the azimuth of the positive side-looking synthetic aperture sonar, the distance upward , ,……, Location The azimuth coordinates of each target are uniformly taken as: ,in Indicated in , ,……, Location The azimuth coordinates of a common target.

[0066] Based on the principle that the target must be within the observation angle range of the sonar beam, the distance error between the precise instantaneous two-way slant range between the sonar azimuth and the target and the approximate slant range of the imaging method to be evaluated is calculated according to the geometric relationship. The calculation formula of the precise instantaneous two-way slant range is for:

[0067] , where the subscript Indicates The first receiving array element and the transmitting array element are composed of subsystems that satisfy , Represents the total number of receiving array elements, Represents the coordinate of the target in the range direction, Indicates the coordinates of the target in the azimuth direction, Indicates the slow time of the direction, Indicates The first receiving array element and the transmitting array element are composed of The distance between the transmitting and receiving elements in each subsystem, Indicates the speed of the sonar platform in azimuth. Represents the speed of sound underwater.

[0068] In the one-dimensional error analysis method of the present invention, the imaging method to be evaluated is the approximate slant range history derived based on the second-order order approximation method in the academic paper "Research on Multi-Subarray SAS Line-by-Line Imaging Algorithm" published by Wang Haitao in the Journal of Harbin Engineering University in 2009, and its expression is: .

[0069] Two-pass slope range history for the imaging method to be evaluated , using the precise instantaneous two-way slant range calculated for the receiving element to be investigated Calculate the distance error between the approximate slant ranges of the imaging methods to be evaluated , and its calculation formula is: ,in Indicates the slow time of the direction, represents the approximate two-pass slant range history of the imaging method to be evaluated, represents the calculated precise instantaneous two-way slant distance, Indicates the distance error.

[0070] According to the criterion that the partial derivative of the distance error with respect to the distance is zero, the minimum number of targets to be set and their coordinates in the distance direction are determined in the imaging area, where the calculation formula for the partial derivative of the distance error with respect to the distance to be zero is: ,in represents the distance error between the precise instantaneous two-way slant range and the approximate slant range of the imaging method to be evaluated, Indicates the distance of the target in the range direction, It represents the partial derivative of the distance error with respect to the distance. A zero partial derivative indicates the maximum or minimum value of the distance error in the distance direction. The target distances that must be considered when setting the target are: the closest distance, the farthest distance, the distance where the maximum value is located, and the distance where the minimum value is located. Assume that the total number of maximum values ​​and minimum values ​​is , then the total number of targets to be set is , where the distance coordinates of the nearest target are , the distance coordinate of the farthest target is . Corresponds to The established distance is defined as , ,……, .

[0071] Here we will accurately calculate the slope distance and the approximate slant range history of the imaging method to be evaluated Substitution After that, it was found Either it is always greater than 0 or always less than 0, that is, the distance error It's about distance A monotonic function of .

[0072] According to the principle that the partial derivative of the distance error with respect to the spacing between the transmitting and receiving array elements is zero, the receiving array element whose distance error is to be investigated is determined in the imaging area. The calculation formula for the partial derivative of the distance error with respect to the spacing between the transmitting and receiving array elements to be zero is: ,in represents the distance error between the precise instantaneous two-way slant range and the approximate slant range of the imaging method to be evaluated, Represents the distance between the transmitting array element and the receiving array element, It represents the partial derivative of the distance error with respect to the distance between the transmitting and receiving array elements. The partial derivative of zero indicates the maximum or minimum value of the distance error in the dimension of the distance between the transmitting and receiving array elements. The transmitting and receiving array elements that must be considered when setting the target are: the receiving array element with the closest distance between the transmitting and receiving array elements, the receiving array element with the farthest distance between the transmitting and receiving array elements, the receiving array element corresponding to the maximum value, and the receiving array element corresponding to the minimum value. Assume that the total number of maximum and minimum values ​​is , then the total number of receiving array elements that need to be examined is ,in Indicates the distance between the transmitting and receiving array elements when they are closest. Indicates the distance when the distance between the transmitting and receiving array elements is the farthest. The obtained transceiver array element spacing is rounded to an integer After processing, other receiving array elements that need to examine the distance error are obtained.

[0073] Here we will accurately calculate the slope distance and the approximate slant range history of the imaging method to be evaluated Substitution After that, it was found is always greater than 0, that is, the distance error It is about the spacing between the transceiver array elements A monotonic function of .

[0074] According to the target distance and receiving array elements calculated in advance, the distance error between the precise instantaneous two-way slant range and the approximate slant range of the imaging method to be evaluated is calculated using the following formula: ,in Indicates the slow time of the direction, Indicates the number of imaging methods to be evaluated for the space. The approximate two-way slant range history calculated for each target satisfies , Indicates the total number of targets set. Indicates the number of The precise instantaneous two-way slant range calculated for each target is calculated using the following formula:

[0075] ,

[0076] The subscript Indicates The first receiving array element and the transmitting array element are composed of subsystems that satisfy , Represents the total number of receiving array elements, Represents the coordinate of the target in the range direction, Indicates the coordinates of the target in the azimuth direction, Indicates the slow time of the direction, Indicates The first receiving array element and the transmitting array element are composed of The distance between the transmitting and receiving elements in each subsystem, Indicates the speed of the sonar platform in azimuth. Represents the speed of sound underwater.

[0077] Assume that the aperture of the transmitting array element along the azimuth direction is 8cm, the aperture of the receiving array element along the azimuth direction is 4cm, there are 30 receiving array elements in total, the transmitting signal is a linear frequency modulation signal, the center frequency is 150kHz, the bandwidth is 20kHz, and the pulse repetition frequency of the transmitting signal is 0.3s. Assume that there are two ideal point targets in space, the coordinate of the close-range target in the range direction is 35m, the coordinate of the long-range target in the range direction is 205m, and the coordinates of the two targets in the azimuth direction are both 10.6m. The results of imaging using traditional imaging methods are as follows Figure 3 As shown, Figure 3 (a) is the target imaging result at a distance of 35m. Figure 3 (b) is the target imaging result at a distance of 205m; Figure 3 (c) is the azimuth profile of the target after focusing at a distance of 35 m; Figure 3 (d) is the azimuth profile of the target after focusing at a distance of 205m. It is not difficult to find that the traditional performance evaluation method needs to first design the imaging method according to the approximate distance model, write the imaging program, and then count the peak sidelobe ratio, integrated sidelobe ratio and azimuth resolution of the azimuth profile of the imaging result to evaluate the pros and cons of the method. The whole process is cumbersome. The performance statistics are shown in Table 1.

[0078] Table 1 Evaluation results of azimuth focusing performance of traditional methods

[0079]

[0080] For the 8 cm transmitting array element and 4 cm receiving array element in this embodiment, the joint directivity function obtained by simulation is as follows: Figure 4As shown in the figure, the beam width of the sonar system is 5.912°. Based on the beam width, the synthetic aperture length of the target at a distance of 205m can be obtained to be 21.2m, so the coordinates of the two targets in the azimuth direction are set to 10.6m. By solving the partial derivative of the error, it is found that the partial derivative is a monotonic function of the distance. In addition, the partial derivative is also a monotonic function of the spacing between the transmitting and receiving array elements. Therefore, according to the one-dimensional error analysis method of the present invention, the coordinates of the close-range target in the distance direction are set to 35m, and the coordinates of the long-range target in the distance direction are set to 205m. The distance error simulated according to the set parameters is shown in Figure 5 As shown, it is not difficult to find that the error is very small, that is, Wang Haitao's approximate slant range history can complete high-resolution imaging under the parameters of this embodiment. The one-dimensional error analysis method of the present invention does not need to complete the cumbersome process of designing the imaging algorithm, programming, simulating imaging, etc. according to the approximate slant range history to obtain the evaluation result, but can quickly and conveniently obtain the distance error according to the approximate slant range history, thereby judging whether the approximate slant range history can meet the high-resolution imaging requirements based on whether the error is much smaller than the wavelength, which greatly improves the efficiency of imaging method modeling.

[0081] Attached Figure 6 A one-dimensional error analysis method according to a preferred embodiment of the present invention is shown, which is used to quickly evaluate the pros and cons of the distance approximation imaging method, thereby guiding the design of the imaging algorithm. Figure 1 The one-dimensional error analysis method of the present invention comprises the following steps: S1, calculating the joint directivity function of the transmitting and receiving array elements according to the directivity functions of the transmitting and receiving array elements respectively, so as to determine the beam width of the sonar system; S2, calculating the coordinates of the target to be set in the azimuth direction in the imaging area according to the farthest imaging distance and the beam width of the sonar system; S3, based on the principle that the target must be within the observation angle range of the sonar beam, calculating the distance error between the precise instantaneous two-way slant range between different positions of the sonar azimuth and the target and the approximate slant range of the imaging method to be evaluated according to the geometric relationship; S4, determining the minimum number of targets to be set and their coordinates in the distance direction in the imaging area according to the principle that the partial derivative of the distance error with respect to the distance is zero; S5, determining the receiving array element whose distance error is to be investigated in the imaging area according to the principle that the partial derivative of the distance error with respect to the spacing between the transmitting and receiving array elements is zero; S6, calculating the distance error between the precise instantaneous two-way slant range and the approximate slant range of the imaging method to be evaluated according to the target distance and the receiving array element calculated in advance.

[0082] In a specific example of the one-dimensional error analysis method of the present invention, in step S1, the calculation formula for calculating the joint directivity function of the transmitting and receiving array elements is: ,in represents the directivity function of the transmitting array element, represents the directivity function of the receiving array element, Represents the directivity function of the transmitting and receiving array elements of the sonar system, Indicates the angle between the target sonar line of sight and the sonar positive side view direction; for the joint directivity function After normalization and logarithm processing, the formula is: , where the joint directivity function The difference between the two angle values ​​corresponding to the maximum value dropping by -3dB is the beam width of the sonar system. , Indicates maximum value processing. Indicates taking absolute value.

[0083] In a specific example of the one-dimensional error analysis method of the present invention, in step S2, according to the farthest imaging distance and beam width of the sonar system, the calculation formula for calculating the coordinates of the target to be set in the azimuth direction in the imaging area is: ,in It represents the synthetic aperture length corresponding to the target at the farthest distance, and its expression is ,in Indicates the distance of the target at the farthest distance, Indicates the beam width of the sonar system. The value corresponding to the azimuth coordinate of the target at the farthest distance cannot be less than , considering the non-spatial nature of the azimuth of the positive side-looking synthetic aperture sonar, the distance upward , ,……, Location The azimuth coordinates of each target are uniformly taken as: ,in Indicated in , ,……, Location The azimuth coordinates of a common target.

[0084] In a specific example of the one-dimensional error analysis method of the present invention, in step S3, the precise instantaneous two-way slope distance is calculated. The calculation formula is: , where the subscript Indicates The first receiving array element and the transmitting array element are composed of subsystems that satisfy , Represents the total number of receiving array elements, Represents the coordinate of the target in the range direction, Indicates the coordinates of the target in the azimuth direction, Indicates the slow time of the direction, Indicates The first The distance between the transmitting and receiving elements in each subsystem, Indicates the speed of the sonar platform in azimuth. represents the speed of sound underwater;

[0085] Two-pass slope range history for the imaging method to be evaluated , using the precise instantaneous two-way slant range calculated for the receiving element to be investigated Calculate the distance error between the approximate slant ranges of the imaging methods to be evaluated , and its calculation formula is: .

[0086] In a specific example of the one-dimensional error analysis method of the present invention, in step S4, the calculation formula for the partial derivative of the distance error with respect to the distance to be zero is: ,in represents the distance error between the precise instantaneous two-way slant range and the approximate slant range of the imaging method to be evaluated, Indicates the distance of the target in the range direction, It represents the partial derivative of the distance error with respect to the distance. A partial derivative of zero indicates the maximum or minimum value of the distance error in the distance direction. When setting the target, the closest distance, the farthest distance, the maximum distance and the minimum distance of the target are considered. Let the total number of maximum and minimum values ​​be , the total number of targets to be set is , where the distance coordinates of the nearest target are , the distance coordinate of the farthest target is , corresponding to The established distance is defined as , ,……, .

[0087] In a specific example of the one-dimensional error analysis method of the present invention, in step S5, the calculation formula for the partial derivative of the distance error with respect to the transceiver array element spacing to be zero is: ,in represents the distance error between the precise instantaneous two-way slant range and the approximate slant range of the imaging method to be evaluated, Represents the distance between the transmitting array element and the receiving array element, It represents the partial derivative of the distance error with respect to the distance between the transmitting and receiving array elements. The partial derivative of zero indicates the maximum or minimum value of the distance error in the dimension of the distance between the transmitting and receiving array elements. When setting the target, it is necessary to consider the receiving array element with the closest distance between the transmitting and receiving array elements, the receiving array element with the farthest distance between the transmitting and receiving array elements, the receiving array element corresponding to the maximum value, and the receiving array element corresponding to the minimum value. Let the total number of maximum and minimum values ​​be , the total number of receiving array elements that need to be examined is ,in Indicates the distance between the transmitting and receiving array elements when they are closest. Indicates the distance when the distance between the transmitting and receiving array elements is the farthest. The obtained transceiver array element spacing is rounded to an integer After processing, other receiving array elements that need to examine the distance error are obtained.

[0088] In a specific example of the one-dimensional error analysis method of the present invention, the calculation formula for calculating the distance error between the precise instantaneous two-way slant range and the approximate slant range of the imaging method to be evaluated is: ,in Indicates the slow time of the direction, Indicates the number of imaging methods to be evaluated for the space. The approximate two-way slant range history calculated for each target satisfies , Indicates the total number of targets set. Indicates the number of The precise instantaneous two-way slant range calculated for each target is calculated using the following formula:

[0089] , where the subscript Indicates The first receiving array element and the transmitting array element are composed of subsystems that satisfy , Represents the total number of receiving array elements, Represents the coordinate of the target in the range direction, Indicates the coordinates of the target in the azimuth direction, Indicates the slow time of the direction, Indicates The first receiving array element and the transmitting array element are composed of The distance between the transmitting and receiving elements in each subsystem, Indicates the speed of the sonar platform in azimuth. Represents the speed of sound underwater.

[0090] Attached Figure 7A one-dimensional error analysis system 700 according to a preferred embodiment of the present invention is shown, wherein the one-dimensional error analysis system 700 includes a first calculation unit 710, a second calculation unit 720, a third calculation unit 730, a first determination unit 740, a second determination unit 750 and a fourth calculation unit 760.

[0091] Specifically, the first calculation unit 710 is used to calculate the joint directivity function of the transmitting and receiving array elements according to the directivity functions of the transmitting and receiving array elements, so as to determine the beam width of the sonar system. The second calculation unit 720 is used to calculate the coordinates of the target to be set in the azimuth direction in the imaging area according to the farthest imaging distance and beam width of the sonar system. The third calculation unit 730 is used to calculate the distance error between the precise instantaneous two-way slant range between different positions of the sonar azimuth and the target and the approximate slant range of the imaging method to be evaluated according to the geometric relationship based on the principle that the target must be within the observation angle range of the sonar beam. The first determination unit 740 is used to determine the minimum number of targets to be set and their coordinates in the distance direction in the imaging area according to the principle that the partial derivative of the distance error with respect to the distance is zero. The second determination unit 750 is used to determine the receiving array element whose distance error is to be investigated in the imaging area according to the principle that the partial derivative of the distance error with respect to the spacing between the transmitting and receiving array elements is zero. The fourth calculation unit 760 is used to calculate the distance error between the precise instantaneous two-way slant range and the approximate slant range of the imaging method to be evaluated according to the target distance and receiving array elements calculated in advance.

[0092] In a specific example of the one-dimensional error analysis system 700 of the present invention, the calculation formula used by the first calculation unit 710 to calculate the joint directivity function of the transmitting and receiving array elements is: ,in represents the directivity function of the transmitting array element, represents the directivity function of the receiving array element, Represents the directivity function of the transmitting and receiving array elements of the sonar system, Indicates the angle between the target sonar line of sight and the sonar positive side view direction; for the joint directivity function After normalization and logarithm processing, the formula is: , where the joint directivity function The difference between the two angle values ​​corresponding to the maximum value dropping by -3dB is the beam width of the sonar system. , Indicates maximum value processing. Indicates taking absolute value.

[0093] In a specific example of the one-dimensional error analysis system 700 of the present invention, the second calculation unit 720 is used to calculate the coordinates of the target to be set in the azimuth direction in the imaging area according to the farthest imaging distance and beam width of the sonar system. ,in It represents the synthetic aperture length corresponding to the target at the farthest distance, and its expression is ,in Indicates the distance of the target at the farthest distance, Indicates the beam width of the sonar system. The value corresponding to the azimuth coordinate of the target at the farthest distance cannot be less than , considering the non-spatial nature of the azimuth of the positive side-looking synthetic aperture sonar, the distance upward , ,……, Location The azimuth coordinates of each target are uniformly taken as: ,in Indicated in , ,……, Location The azimuth coordinates of a common target.

[0094] In a specific example of the one-dimensional error analysis system 700 of the present invention, the third calculation unit 730 is used to calculate the precise instantaneous two-way slope distance. The calculation formula is: , where the subscript Indicates The first subsystems that satisfy , Indicates the total number of receiving array elements, Indicates the coordinates of the target in the range direction, Indicates the coordinates of the target in the azimuth direction, Indicates the slow time of the direction, Indicates The first The distance between the transmitting and receiving elements in each subsystem, Indicates the speed of the sonar platform in azimuth. represents the speed of sound underwater;

[0095] Two-pass slope range history for the imaging method to be evaluated , using the precise instantaneous two-way slant range calculated for the receiving element to be investigated Calculate the distance error between the approximate slant ranges of the imaging methods to be evaluated , and its calculation formula is: .

[0096] In a specific example of the one-dimensional error analysis system 700 of the present invention, the calculation formula for the partial derivative of the distance error with respect to the distance to be zero is: ,in represents the distance error between the precise instantaneous two-way slant range and the approximate slant range of the imaging method to be evaluated, Indicates the distance of the target in the range direction, It represents the partial derivative of the distance error with respect to the distance. A partial derivative of zero indicates the maximum or minimum value of the distance error in the distance direction. When setting the target, the closest distance, the farthest distance, the maximum distance and the minimum distance of the target are considered. Let the total number of maximum and minimum values ​​be , the total number of targets to be set is , where the distance coordinates of the nearest target are , the distance coordinate of the farthest target is , corresponding to The established distance is defined as , ,……, .

[0097] In a specific example of the one-dimensional error analysis system 700 of the present invention, the calculation formula for the partial derivative of the distance error with respect to the spacing between the transmitting and receiving array elements to be zero is: ,in represents the distance error between the precise instantaneous two-way slant range and the approximate slant range of the imaging method to be evaluated, Represents the distance between the transmitting array element and the receiving array element, It represents the partial derivative of the distance error with respect to the distance between the transmitting and receiving array elements. The partial derivative of zero indicates the maximum or minimum value of the distance error in the dimension of the distance between the transmitting and receiving array elements. When setting the target, it is necessary to consider the receiving array element with the closest distance between the transmitting and receiving array elements, the receiving array element with the farthest distance between the transmitting and receiving array elements, the receiving array element corresponding to the maximum value, and the receiving array element corresponding to the minimum value. Let the total number of maximum and minimum values ​​be , the total number of receiving array elements that need to be examined is ,in Indicates the distance between the transmitting and receiving array elements when they are closest. Indicates the distance when the distance between the transmitting and receiving array elements is the farthest. The obtained transceiver array element spacing is rounded to an integer After processing, other receiving array elements that need to examine the distance error are obtained.

[0098] In a specific example of the one-dimensional error analysis system 700 of the present invention, the fourth calculation unit 760 is used to calculate the distance error between the precise instantaneous two-way slant range and the approximate slant range of the imaging method to be evaluated, using the following calculation formula: ,in Indicates the slow time of the direction, Indicates the number of imaging methods to be evaluated for the space. The approximate two-way slant range history calculated for each target satisfies , Indicates the total number of targets set. Indicates the number of The precise instantaneous two-way slant range calculated for each target is calculated using the following formula:

[0099] , where the subscript Indicates The first subsystems that satisfy , Indicates the total number of receiving array elements, Indicates the coordinates of the target in the range direction, Indicates the coordinates of the target in the azimuth direction, Indicates the slow time of the direction, Indicates The first The distance between the transmitting and receiving elements in each subsystem, Indicates the speed of the sonar platform in azimuth. Represents the speed of sound underwater.

[0100] Attached Figure 8A computing device 800 according to a preferred embodiment of the present invention is shown, wherein the computing device 800 includes a memory 810 and a processor 820 coupled to the memory 810, wherein the memory 810 is used to store computer program instructions, and when the computer program instructions are executed in the processor 820, the processor 820 executes a one-dimensional error analysis method, wherein the one-dimensional error analysis method includes the following steps: calculating the joint directivity function of the transmitting and receiving array elements according to the respective directivity functions of the transmitting and receiving array elements to determine the beam width of the sonar system; calculating the beam width to be set in the imaging area according to the farthest imaging distance and the beam width of the sonar system; The coordinates of the target in azimuth are set; based on the principle that the target must be within the observation angle range of the sonar beam, the distance error between the precise instantaneous two-way slant range between the sonar position and the target and the approximate slant range of the imaging method to be evaluated is calculated according to the geometric relationship; based on the principle that the partial derivative of the distance error with respect to the distance is zero, the minimum number of targets to be set and their coordinates in the range direction are determined in the imaging area; based on the principle that the partial derivative of the distance error with respect to the spacing between the transmitting and receiving array elements is zero, the receiving array elements to be examined for the distance error are determined in the imaging area; based on the target distance and the receiving array elements calculated in advance, the distance error between the precise instantaneous two-way slant range and the approximate slant range of the imaging method to be evaluated is calculated.

[0101] In one embodiment of the computing device 800 of the present invention, the memory 810 may include one or more computer program products, and the computer program product may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may include, for example, a random access memory (RAM) and / or a cache memory (cache), etc. The non-volatile memory may include, for example, a read-only memory (ROM), a hard disk, a flash memory, etc. One or more computer program instructions may be stored on the computer-readable storage medium, and the processor 820 may execute the program instructions to implement the functions of the one-dimensional error analysis method of the present invention described above.

[0102] In one embodiment of the computing device 800 of the present invention, the processor 820 can be a central processing unit (CPU) or other forms of processing units with data processing capabilities and / or instruction execution capabilities, which can run the program instructions stored on the computer-readable storage medium to implement the functions of the one-dimensional error analysis method of the present invention described above.

[0103] In one embodiment of the linear frequency modulation scaling imaging system of the present invention, the computing device 800 may also include an input device 830 and an output device 840. The input device 830 may be but is not limited to a keyboard or a mouse. The output device 840 may be but is not limited to a display, a speaker, or a printer. The input device 830 and the output device 840 may be connected to the processor 820 via a bus system.

[0104] It should be understood by those skilled in the art that the embodiments of the present invention described above and shown in the accompanying drawings are only examples and do not limit the present invention. The purpose of the present invention has been fully and effectively achieved. The functional and structural principles of the present invention have been demonstrated and explained in the embodiments, and the embodiments of the present invention may be modified or altered in any way without departing from the principles.

Claims

1. A one-dimensional error analysis method for synthetic aperture sonar imaging method, characterized in that: The one-dimensional error analysis method comprises the following steps: S1, calculating the joint directivity function of the transmitting and receiving array elements according to their respective directivity functions to determine the beam width of the sonar system; S2, calculating the coordinates of the target to be set in the azimuth direction in the imaging area according to the farthest imaging distance and beam width of the sonar system; S3, based on the principle that the target must be within the observation angle range of the sonar beam, the distance error between the precise instantaneous two-way slant range between the sonar azimuth and the target and the approximate slant range of the imaging method to be evaluated is calculated according to the geometric relationship. The imaging method to be evaluated is the approximate slant range derived based on the second-order approximation method, and its expression is: ; S4, according to the principle that the partial derivative of the distance error with respect to the distance is zero, determining the minimum number of targets to be set in the imaging area and the coordinates in the distance direction; S5, determining the receiving array element whose distance error is to be investigated in the imaging area according to the principle that the partial derivative of the distance error with respect to the spacing between the transmitting and receiving array elements is zero; S6, calculating the distance error between the precise instantaneous two-way slant range and the approximate slant range of the imaging method to be evaluated based on the target distance and receiving array elements calculated in advance, wherein the calculation formula for calculating the distance error between the precise instantaneous two-way slant range and the approximate slant range of the imaging method to be evaluated is: , in Indicates the slow time of the direction, Indicates the number of imaging methods to be evaluated for the space. The approximate two-way slant range history calculated for each target satisfies , Indicates the total number of targets set. Indicates the number of The precise instantaneous two-way slant range calculated for each target is calculated using the following formula: ， The subscript Indicates The first subsystems that satisfy , Indicates the total number of receiving array elements, Represents the coordinate of the target in the range direction, Indicates the coordinates of the target in the azimuth direction, Indicates the slow time of the direction, Indicates The first The distance between the transmitting and receiving elements in each subsystem, Indicates the speed of the sonar platform in azimuth. represents the speed of sound underwater, Indicates the coordinates of the target in the range direction.

2. The one-dimensional error analysis method according to claim 1, characterized in that: In step S1, the calculation formula for calculating the joint directivity function of the transmitting and receiving array elements is: , in represents the directivity function of the transmitting array element, represents the directivity function of the receiving array element, represents the joint directivity function of the transmitting and receiving array elements of the sonar system, Indicates the angle formed by the target sonar line of sight and the sonar positive side view direction; For joint directivity function After normalization and logarithm processing, the formula is: , The joint directivity function The difference between the two angle values ​​corresponding to the maximum value dropping by -3dB is the beam width of the sonar system. , Indicates maximum value processing. Indicates taking absolute value.

3. The one-dimensional error analysis method according to claim 1, characterized in that: In step S2, according to the farthest imaging distance and beam width of the sonar system, the calculation formula for calculating the coordinates of the target to be set in the azimuth direction in the imaging area is: , in It represents the synthetic aperture length corresponding to the target at the farthest distance, and its expression is ,in Indicates the distance of the target at the farthest distance, Indicates the beam width of the sonar system. The value corresponding to the azimuth coordinate of the target at the farthest distance cannot be less than , considering the non-spatial nature of the azimuth of the positive side-looking synthetic aperture sonar, the distance upward , ,……, Location The azimuth coordinates of each target are uniformly taken as: ,in Indicated in , ,……, Location The azimuth coordinates of a common target.

4. The one-dimensional error analysis method according to claim 1, characterized in that: In step S3, the precise instantaneous two-way slope distance is calculated The calculation formula is: ; Two-pass slope range history for the imaging method to be evaluated , using the precise instantaneous two-way slant range calculated for the receiving element to be investigated Calculate the distance error between the approximate slant ranges of the imaging methods to be evaluated , and its calculation formula is: .

5. The one-dimensional error analysis method according to claim 1, characterized in that: In step S4, the calculation formula for the partial derivative of the distance error with respect to the distance to be zero is: , in represents the distance error between the precise instantaneous two-way slant range and the approximate slant range of the imaging method to be evaluated, It represents the partial derivative of the distance error with respect to the distance. A partial derivative of zero indicates the maximum or minimum value of the distance error in the distance direction. When setting the target, the closest distance, the farthest distance, the maximum distance and the minimum distance of the target are considered. Let the total number of maximum and minimum values ​​be , the total number of targets to be set is , where the distance coordinates of the nearest target are , the distance coordinate of the farthest target is , corresponding to The established distance is defined as , ,……, .

6. The one-dimensional error analysis method according to claim 1, characterized in that: In step S5, the calculation formula for the partial derivative of the distance error with respect to the distance between the transmitting and receiving array elements to be zero is: ,in represents the distance error between the precise instantaneous two-way slant range and the approximate slant range of the imaging method to be evaluated, Represents the distance between the transmitting array element and the receiving array element, It represents the partial derivative of the distance error with respect to the distance between the transmitting and receiving array elements. The partial derivative of zero indicates the maximum or minimum value of the distance error in the dimension of the distance between the transmitting and receiving array elements. When setting the target, it is necessary to consider the receiving array element with the closest distance between the transmitting and receiving array elements, the receiving array element with the farthest distance between the transmitting and receiving array elements, the receiving array element corresponding to the maximum value, and the receiving array element corresponding to the minimum value. Let the total number of maximum and minimum values ​​be , the total number of receiving array elements that need to be examined is ,in Indicates the distance when the transmitting and receiving elements are closest to each other. Indicates the distance when the distance between the transmitting and receiving array elements is the farthest. The obtained transceiver array element spacing is rounded to an integer After processing, other receiving array elements that need to examine the distance error are obtained.

7. A one-dimensional error analysis system for synthetic aperture sonar imaging method, characterized in that: include: A first calculation unit is used to calculate the joint directivity function of the transmitting and receiving array elements according to the directivity functions of the transmitting and receiving array elements, so as to determine the beam width of the sonar system; A second calculation unit is used to calculate the coordinates of the target to be set in the azimuth direction in the imaging area according to the farthest imaging distance and beam width of the sonar system; The third calculation unit is used to calculate the distance error between the precise instantaneous two-way slant range between the target and different positions in the sonar azimuth and the approximate slant range of the imaging method to be evaluated based on the principle that the target must be within the observation angle range of the sonar beam according to the geometric relationship, wherein the imaging method to be evaluated is an approximate slant range derived based on the second-order approximation method, and its expression is: ; A first determining unit is used to determine the minimum number of targets to be set and their coordinates in the distance direction in the imaging area according to the principle that the partial derivative of the distance error with respect to the distance is zero; A second determination unit is used to determine the receiving array element whose distance error is to be examined in the imaging area according to the principle that the partial derivative of the distance error with respect to the distance between the transmitting and receiving array elements is zero; The fourth calculation unit is used to calculate the distance error between the precise instantaneous two-way slant range and the approximate slant range of the imaging method to be evaluated according to the target distance and the receiving array element calculated in advance, wherein the calculation formula for calculating the distance error between the precise instantaneous two-way slant range and the approximate slant range of the imaging method to be evaluated is: , in Indicates the slow time of the direction, Indicates the number of imaging methods to be evaluated for the space. The approximate two-way slant range history calculated for each target satisfies , Indicates the total number of targets set. Indicates the number of The precise instantaneous two-way slant range calculated for each target is calculated using the following formula: ， The subscript Indicates The first subsystems that satisfy , Indicates the total number of receiving array elements, Represents the coordinate of the target in the range direction, Indicates the coordinates of the target in the azimuth direction, Indicates the slow time of the direction, Indicates The first The distance between the transmitting and receiving elements in each subsystem, Indicates the speed of the sonar platform in azimuth. represents the speed of sound underwater, Indicates the coordinates of the target in the range direction.

8. The one-dimensional error analysis system according to claim 7, characterized in that: The third calculation unit is used to calculate the precise instantaneous two-way slope distance The calculation formula is: ; Two-pass slope range history for the imaging method to be evaluated , using the precise instantaneous two-way slant range calculated for the receiving element to be investigated Calculate the distance error between the approximate slant ranges of the imaging methods to be evaluated , and its calculation formula is: .

9. The one-dimensional error analysis system according to claim 7, characterized in that: The calculation formula for calculating the joint directivity function of the transmitting and receiving array elements by the first calculation unit is: , in represents the directivity function of the transmitting array element, represents the directivity function of the receiving array element, represents the joint directivity function of the transmitting and receiving array elements of the sonar system, Indicates the angle formed by the target sonar line of sight and the sonar positive side view direction; For joint directivity function After normalization and logarithm processing, the formula is: , The joint directivity function The difference between the two angle values ​​corresponding to the maximum value dropping by -3dB is the beam width of the sonar system. , Indicates maximum value processing. Indicates taking absolute value.

10. A computing device, characterized in that The method comprises a processor and a memory, wherein the memory stores computer program instructions, and when the computer program instructions are executed in the processor, the processor executes the one-dimensional error analysis method according to any one of claims 1 to 6.

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