Transmit-receive co-location synthetic aperture sonar return simulation method, system, and apparatus

Abstract

The application discloses a kind of transceiving synthetic aperture sonar echo simulation method, system and device, it is related to image processing technical field, the sonar echo simulation method includes the following steps: according to the transmission distance between sonar and single target at signal emission time, the receiving distance between sonar and single target at echo signal receiving time, the accurate propagation time of signal from transmission to receiving is calculated;According to the two-dimensional coordinates of single target, the calculated transmission distance, the calculated receiving distance, the two-way distance that signal has experienced is calculated, the modulated wideband signal after transmission is carried out delay processing, obtains the echo signal corresponding to single target, for other arbitrary target in space, the two-dimensional coordinates corresponding to target are transformed and then calculated iteratively according to the above steps, obtain the echo signal corresponding to other arbitrary target in space, the echo signal of all targets is coherently accumulated in time domain, then demodulation is carried out to obtain baseband echo signal.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of image processing, in particular to a kind of transceiver combined synthetic aperture sonar echo simulation method, system and device, wherein the sonar echo simulation method can meet the accurate simulation of combined synthetic aperture sonar echo signal. BACKGROUND

[0002] Synthetic aperture sonar is a kind of high-resolution imaging device, which can provide "compared with optical image" underwater acoustic image, is conducive to underwater search and rescue, underwater small target detection and identification, underwater mapping, underwater geological exploration and other underwater engineering applications. Transceiver combined synthetic aperture sonar uses one array element to transmit signals and receive echoes, which is relatively simple. However, when simulating echo signals, the traditional transceiver combined synthetic aperture sonar considers that the sonar transmitting and receiving signals is stationary, which ignores the distance along the azimuth direction during the transceiver combined synthetic aperture sonar transmitting and receiving signals. In fact, the transceiver combined synthetic aperture sonar in working state always maintains uniform linear motion, rather than stationary. When the target is located at a short distance, the distance along the azimuth direction during the transceiver combined synthetic aperture sonar transmitting and receiving signals has relatively small influence on the simulation of echoes. When the target is located at a long distance, it will cause inaccurate calculation of receiving distance, leading to inaccurate calculation of Doppler phase and range migration, and ultimately resulting in inaccurate simulation of echoes. In fact, before the real transceiver combined synthetic aperture sonar equipment is developed, the simulated echo is the only source of various signal processing methods including transceiver combined synthetic aperture sonar imaging algorithm, image processing algorithm and interference signal processing algorithm, which plays an important supporting role in the development of the whole signal processing software of the equipment. If inaccurate echoes are used as input, the developed signal processing software cannot better image and process targets at a long distance, which leads to the performance degradation of the imaging results of targets at a long distance, and even defocus. Therefore, it is necessary to study the echo simulation method under the condition of approaching the real motion of the transceiver combined synthetic aperture sonar, so as to provide input echoes under the condition of approaching the real situation for the development of the signal processing software of the whole system, which has very important practical significance for the performance improvement of long-distance target imaging. SUMMARY

[0003] In view of the above technical problems, the present application provides a transceiver combined synthetic aperture sonar echo simulation method, which can accurately simulate the transceiver combined synthetic aperture sonar echo under the condition of the transceiver combined synthetic aperture sonar moving along the azimuth direction during transmitting and receiving signals, wherein the sonar echo simulation method comprises the following steps:

[0004] S1. Calculate the transmission distance between the transceiver synthetic aperture sonar and the single target based on the two-dimensional coordinates of the transceiver synthetic aperture sonar and the single target at the time of signal transmission.

[0005] S2, calculate the receiving distance between the transceiver synthetic aperture sonar and the single target based on the two-dimensional coordinates of the transceiver synthetic aperture sonar and the target at the time of echo signal reception.

[0006] S3. Calculate the precise propagation time of the signal from transmission to reception based on the transmission distance between the combined transceiver synthetic aperture sonar and the single target at the time of signal transmission and the reception distance between the combined transceiver synthetic aperture sonar and the single target at the time of echo signal reception.

[0007] S4. Based on the two-dimensional coordinates of a single target, the transmission distance between the transceiver synthetic aperture sonar and the single target at the time of signal transmission, and the reception distance between the transceiver synthetic aperture sonar and the single target at the time of echo signal reception, calculate the two-way distance traversed by the signal, perform time delay processing on the transmitted modulated broadband signal, and obtain the echo signal corresponding to the single target.

[0008] S5. For any other target in space, after transforming the two-dimensional coordinates corresponding to the target, perform iterative calculations according to the above steps to obtain the echo signal corresponding to any other target in space.

[0009] S6 performs coherent accumulation of the echo signals of all targets in the time domain, and then demodulates them to obtain the baseband echo signal.

[0010] Preferably, in step S1, it is assumed that the system starts at the origin of the coordinate system, and after... After a certain time, at a certain speed The coordinates of the moving synthetic aperture sonar in the azimuth direction are: The coordinate of the target in the range direction is 0, and the coordinate of the target in the azimuth direction is... The coordinates in the distance direction are ,calculate At time t, the transmission distance between the combined transceiver synthetic aperture sonar and a single target at the signal transmission time. for: .

[0011] Preferably, in step S2, it is assumed that the precise propagation time of the signal from transmission to reception is... With speed Motion-based synthetic aperture sonar with combined transmitter and receiver operates on the precise propagation time of signals from transmission to reception. The distance of the inner azimuth movement is At this time, the coordinate of the transceiver array synthetic aperture sonar in the azimuth direction is The receiving distance between the transceiver array synthetic aperture sonar at the echo signal receiving time and the single target is . .

[0012] Preferably, in the step S3, the accurate propagation time of the signal from the transmission to the reception solved by the step S3 corresponds to the sum of the transmission distance calculated by the step S1 and the receiving distance calculated by the step S2, so the equation established is: , wherein represents the sound speed in water, and through solving the above equation, the accurate propagation time of the signal from the transmission to the reception is The accurate expression of the propagation time is: .

[0013] Preferably, in the step S4, the transmission distance between the transceiver array synthetic aperture sonar at the signal transmission time and the single target is , the receiving distance between the transceiver array synthetic aperture sonar at the echo signal receiving time and the single target is , and the two-way distance of the signal is: , assuming that represents the frequency modulation rate, represents the fast time corresponding to the range direction, represents the carrier frequency, and the transmitted wideband signal is a linear frequency modulation signal , then the modulated transmission signal is , and after the delay processing, the echo signal is , and the expression is: , wherein represents the imaginary unit.

[0014] Preferably, in the step S5, assuming that the coordinate of any other target in the space in the azimuth direction is , the coordinate in the range direction is , and the two-way distance of the signal calculated according to the step S4 is: , and the echo signal corresponding to the target is: .

[0015] Preferably, in the step S6, the expression of the coherent accumulation is: , the total number of the targets is , and then the demodulation of the coherent accumulated echo signal is performed, and the expression is: .

[0016] According to another aspect of the present application, the present application further provides a transceiver combined synthetic aperture sonar echo simulation system for echo simulation of a transceiver combined synthetic aperture sonar, wherein the sonar echo simulation system comprises:

[0017] a first calculation unit configured to calculate a transmission distance between the transceiver combined synthetic aperture sonar and the single target at the signal transmission time according to the two-dimensional coordinates of the transceiver combined synthetic aperture sonar at the signal transmission time and the two-dimensional coordinates of the single target;

[0018] a second calculation unit configured to calculate a receiving distance between the transceiver combined synthetic aperture sonar and the single target at the echo signal receiving time according to the two-dimensional coordinates of the transceiver combined synthetic aperture sonar at the echo signal receiving time and the two-dimensional coordinates of the single target;

[0019] a third calculation unit configured to calculate an accurate propagation time of the signal from the transmission to the receiving according to the transmission distance between the transceiver combined synthetic aperture sonar and the single target at the signal transmission time and the receiving distance between the transceiver combined synthetic aperture sonar and the single target at the echo signal receiving time;

[0020] an echo signal acquisition unit configured to calculate a two-way distance of the signal according to the two-dimensional coordinates of the single target, the transmission distance between the transceiver combined synthetic aperture sonar and the single target at the signal transmission time and the receiving distance between the transceiver combined synthetic aperture sonar and the single target at the echo signal receiving time, and to perform a delay processing on the transmitted modulated wideband signal to obtain the echo signal corresponding to the single target;

[0021] an iterative calculation unit configured to perform an iterative calculation according to the above steps after transforming the two-dimensional coordinates of the target for other arbitrary targets in the space to obtain the echo signal corresponding to the other arbitrary targets in the space;

[0022] a coherent accumulation unit configured to perform a coherent accumulation on the echo signals of all targets in the time domain, and then to perform a demodulation to obtain a baseband echo signal.

[0023] Preferably, it is assumed that the system starts at the coordinate origin, and after a time of , the transceiver combined synthetic aperture sonar moving at a speed of has a coordinate of in the azimuth direction and a coordinate of 0 in the range direction, and the single target has a coordinate of in the azimuth direction and a coordinate of in the range direction, the first calculation unit calculates the transmission distance between the transceiver combined synthetic aperture sonar and the single target at the signal transmission time as: . .

[0024] According to another aspect of the present application, the present application further provides a computing device comprising a processor and a memory, wherein computer program instructions are stored in the memory, and the computer program instructions, when executed in the processor, cause the processor to perform the sonar echo simulation method, wherein the sonar echo simulation method comprises the following steps:

[0025] S1, according to the two-dimensional coordinates of the transceiver combined synthetic aperture sonar at the signal transmission moment and the two-dimensional coordinates of the single target, the transmission distance between the transceiver combined synthetic aperture sonar at the signal transmission moment and the single target is calculated;

[0026] S2, according to the two-dimensional coordinates of the transceiver combined synthetic aperture sonar at the echo signal receiving moment and the two-dimensional coordinates of the target, the receiving distance between the transceiver combined synthetic aperture sonar at the echo signal receiving moment and the single target is calculated;

[0027] S3, according to the transmission distance between the transceiver combined synthetic aperture sonar at the signal transmission moment and the single target and the receiving distance between the transceiver combined synthetic aperture sonar at the echo signal receiving moment and the single target, the accurate propagation time of the signal from transmission to reception is calculated;

[0028] S4, according to the two-dimensional coordinates of the single target, the transmission distance between the transceiver combined synthetic aperture sonar at the signal transmission moment and the single target, and the receiving distance between the transceiver combined synthetic aperture sonar at the echo signal receiving moment and the single target, the two-way distance experienced by the signal is calculated, and the transmitted modulated wideband signal is subjected to delay processing to obtain the echo signal corresponding to the single target;

[0029] S5, for other arbitrary targets in space, the two-dimensional coordinates corresponding to the targets are transformed and the above steps are iteratively calculated to obtain the echo signals corresponding to the other arbitrary targets in space;

[0030] S6, the echo signals of all targets are coherently accumulated in the time domain, and then demodulated to obtain the baseband echo signal.

[0031] Compared with the prior art, the present application has at least the following beneficial effects: compared with the traditional transceiver combined synthetic aperture sonar echo simulation method, the sonar echo simulation method of the present application considers the influence of the movement distance of the transceiver combined synthetic aperture sonar along the azimuth direction during signal transmission, so that the simulated echo signal is closer to the actual movement condition of the transceiver combined synthetic aperture sonar, and can provide an input echo closer to the actual movement condition for the transceiver combined synthetic aperture sonar signal processing software, which is beneficial to the improvement of the imaging performance of the long-distance target. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1A flowchart of a transceiver co-located synthetic aperture sonar echo simulation method according to a preferred embodiment of the present application.

[0033] Figure 2 A spatial geometry between the transceiver co-located synthetic aperture sonar and the target according to the sonar echo simulation method of the above preferred embodiment of the present application.

[0034] Figure 3 Echo simulated by a conventional method.

[0035] Figure 4 Echo simulated by the sonar echo simulation method of the above preferred embodiment of the present application.

[0036] Figure 5 Phase error caused by a conventional echo simulation method without considering the motion along the azimuth direction during the transmission and reception of signals.

[0037] Figure 6 Range profiles after imaging processing based on a range-Doppler imaging method suitable for the conventional simulated echo and after imaging processing by the sonar echo simulation method of the present application.

[0038] Figure 7 Azimuth profiles after imaging processing based on a range-Doppler imaging method suitable for the conventional simulated echo and after imaging processing by the sonar echo simulation method of the present application.

[0039] Figure 8 Enlarged view of Figure 7

[0040] Figure 9 A block diagram of a transceiver co-located synthetic aperture sonar echo simulation system according to another preferred embodiment of the present application.

[0041] Figure 10 A block diagram of a computing device according to another preferred embodiment of the present application.

[0042] In the figure:

[0043] 100, sonar echo simulation system; 110, first computing unit; 120, second computing unit; 130, third computing unit; 140, echo signal acquisition unit; 150, iterative computing unit; 160, coherent accumulation unit;

[0044] 200, computing device; 210, processor; 220, memory; 230, input device; 240, output device. DETAILED DESCRIPTION

[0045] ​Before any embodiments of the application are explained in detail, it is to be understood that the application is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The application is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of "including," "comprising" or "having" and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms "mounted," "connected," "supported," and "coupled" and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, "connected" and "coupled" are not restricted to physical or mechanical connections or couplings.

[0046] Also, in the disclosure of the present application, the terms "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, which are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore the above terms cannot be understood as limiting the present application; secondly, the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of one element can be one, and in another embodiment, the number of the element can be multiple, and the term "one" cannot be understood as limiting the number.

[0047] Figure 1The application shows a kind of transceiver combined synthetic aperture sonar echo simulation method of a preferred embodiment of the application, and the specific steps of the sonar echo simulation method include: S1, according to the two-dimensional coordinates of transceiver combined synthetic aperture sonar at signal transmission time and the two-dimensional coordinates of single target, the transmission distance between transceiver combined synthetic aperture sonar and single target at signal transmission time is calculated;S2, according to the two-dimensional coordinates of transceiver combined synthetic aperture sonar at echo signal receiving time and the two-dimensional coordinates of target, the receiving distance between transceiver combined synthetic aperture sonar and single target at echo signal receiving time is calculated;S3, according to the transmission distance between transceiver combined synthetic aperture sonar and single target at signal transmission time, the receiving distance between transceiver combined synthetic aperture sonar and single target at echo signal receiving time, the accurate propagation time of signal from transmission to reception is calculated;S4, according to the two-dimensional coordinates of single target, the transmission distance between transceiver combined synthetic aperture sonar and single target at signal transmission time, the receiving distance between transceiver combined synthetic aperture sonar and single target at echo signal receiving time, the two-way distance experienced by the signal is calculated, the modulated wideband signal is delayed to obtain the echo signal corresponding to single target;S5, for other arbitrary targets in space, the two-dimensional coordinates of the target are transformed and the above steps are iteratively calculated to obtain the echo signal corresponding to other arbitrary targets in space;S6, the echo signals of all targets are coherently accumulated in time domain, and then demodulated to obtain the baseband echo signal. Compared with the traditional transceiver combined synthetic aperture sonar echo simulation method, the sonar echo simulation method of the application considers the influence of the movement distance of transceiver combined synthetic aperture sonar along the azimuth direction during signal transmission and reception, so that the simulated echo signal is closer to the actual movement of transceiver combined synthetic aperture sonar, which can provide input echo closer to the actual movement for transceiver combined synthetic aperture sonar signal processing software, and is beneficial to the improvement of imaging performance of long-distance target.

[0048] Figure 2 The space geometry between transceiver combined synthetic aperture sonar and target is shown, the azimuth direction is the movement azimuth direction of transceiver combined synthetic aperture sonar, and the direction perpendicular to it is the distance direction, the black filled hexagonal star is an ideal point target, the coordinate of the single target in the azimuth direction is , the coordinate in the distance direction is , on the azimuth coordinate axis, the circle represents the element of transceiver combined synthetic aperture sonar, the transceiver combined synthetic aperture sonar moves along the azimuth direction at a constant speed, it is assumed that the system starts at the coordinate origin, the coordinate of transceiver combined synthetic aperture sonar in the distance direction is 0, after time, the transceiver combined synthetic aperture sonar moving at a speed of has a coordinate of in the azimuth direction, so At time t, the transmission distance between the combined transceiver synthetic aperture sonar and a single target at the signal transmission time. for: .

[0049] In step S2, it is assumed that the precise propagation time of the signal from transmission to reception is... So, in terms of speed Motion-based synthetic aperture sonar with combined transmitter and receiver operates on the precise propagation time of signals from transmission to reception. The distance of the inner azimuth movement is At this time, the coordinates of the combined transceiver synthetic aperture sonar in the azimuth direction are... The receiving distance between the transceiver synthetic aperture sonar and a single target at the moment of echo signal reception. for: .

[0050] In step S3, based on the precise propagation time of the signal from transmission to reception, the transmission distance calculated in step S1, and the reception distance calculated in step S2, an equation is established, and the precise propagation time of the signal from transmission to reception is precisely solved. The propagation distance corresponding to the precise propagation time of the signal from transmission to reception calculated in step S3 is necessarily equal to the sum of the transmission distance calculated in step S1 and the reception distance calculated in step S2. Therefore, the established equation is: ,in Let represent the speed of sound in water. By solving the above equation, the precise propagation time of the signal from transmission to reception can be obtained as follows: The precise expression is: .

[0051] In step S4, based on the two-dimensional coordinates of a single target, the transmission distance between the transceiver synthetic aperture sonar and the single target at the time of signal transmission, and the reception distance between the transceiver synthetic aperture sonar and the single target at the time of echo signal reception, the transmitted modulated broadband signal is delayed. The azimuth coordinates of the single target are... The coordinates in the distance direction are The transmission distance between the combined transceiver synthetic aperture sonar and the single target at the moment of signal transmission is The receiving distance between the transceiver synthetic aperture sonar and the single target at the moment of echo signal reception is: The two-way distance traversed by the signal is obtained as follows: Assuming Indicates frequency modulation. This indicates the fast time corresponding to the distance direction. Indicates the carrier frequency; the transmitted wideband signal is a linear frequency modulated signal. Then the modulated transmitting signal is After time delay processing, the echo signal is obtained The expression is: Wherein C represents the sound speed in water, J represents the imaginary unit.

[0052] In step S5, for other arbitrary targets in space, the echo signal corresponding to other arbitrary targets in space is calculated by iteration according to the step S4 after the two-dimensional coordinates of the targets are transformed, wherein it is assumed that the coordinate of other arbitrary targets in space in the azimuth direction is The coordinate of other arbitrary targets in space in the distance direction is The two-way distance of the signal calculated according to the step S4 is: Then the echo signal corresponding to the target is: Wherein C represents the fast time corresponding to the distance direction, C represents the sound speed in water, F represents the frequency modulation rate, F represents the carrier frequency.

[0053] In step S6, the echo signals of all targets are coherently accumulated in the time domain, and then demodulated to obtain the baseband echo signal, wherein the expression of the coherent accumulation is: Herein, the total number of targets is .

[0054] Then the coherently accumulated echo signal is demodulated, and the expression is: Wherein C represents the fast time corresponding to the distance direction, C represents the sound speed in water, F represents the frequency modulation rate, F represents the carrier frequency.

[0055] It is assumed that the towed speed of the transceiver synthetic aperture sonar is 0.125 m / s, the element aperture of the transceiver synthetic aperture sonar in the azimuth direction is 0.08 m, the center frequency of the transmitted linear frequency modulation signal is 150 kHz, the bandwidth is 10 kHz, the pulse repetition frequency is 6.25 Hz, and it is assumed that there is an ideal point target in the scene, the single target has an azimuth coordinate of 10 m and a distance space coordinate of 111 m, the traditional echo simulation method considers that the transceiver synthetic aperture sonar is stationary when transmitting and receiving signals, which ignores the distance of the transceiver synthetic aperture sonar moving along the azimuth direction during the transmitting and receiving signals, and the simulated echo signal is as follows Figure 3As shown, the sonar echo simulation method of the present application fully considers the distance of the motion of the transceiver combined synthetic aperture sonar along the azimuth direction during the transmission and reception of signals, and the simulated echo signal is as shown in Figure 4 As shown, for the single point target set, Figure 5 The phase error caused by the traditional echo simulation method is not difficult to find, which is large and cannot well approximate the real motion condition of the transceiver combined synthetic aperture sonar. The echo simulated by the traditional echo simulation method and the echo simulated by the sonar echo simulation method of the present application are processed by the range-Doppler imaging method suitable for the traditional simulated echo, and the range profile after imaging is as shown in Figure 6 As shown in the figure, it can be seen that the focusing results of the echo simulated by the traditional echo simulation method and the echo simulated by the sonar echo simulation method of the present application are basically consistent in the range direction, that is, the result after imaging by the range-Doppler imaging method suitable for the traditional simulated echo does not bring performance reduction in the range direction under the condition that the sonar echo simulation method of the present application more accurately considers the distance of the motion of the transceiver combined synthetic aperture sonar along the azimuth direction during the transmission and reception of signals. Figure 7 For the profile in the azimuth direction after the echo simulated by the traditional echo simulation method and the echo simulated by the sonar echo simulation method of the present application are processed by the range-Doppler imaging method suitable for the traditional simulated echo, it can be clearly seen from the figure that the range-Doppler imaging method suitable for the traditional simulated echo cannot well process the simulated echo considering the distance of the motion of the transceiver combined synthetic aperture sonar along the azimuth direction during the transmission and reception of signals by the sonar echo simulation method of the present application, so that the sidelobe of the echo processing result of the sonar echo simulation method of the present application is not obvious, wherein Figure 8 For Figure 7 The local enlarged view of the main lobe, it can also be clearly seen from the figure that after the echo simulated by the sonar echo simulation method of the present application is processed by the range-Doppler imaging method suitable for the traditional simulated echo, the main lobe of the azimuth profile has a small offset in the azimuth direction, and there is no sidelobe structure, which reflects that the sonar echo simulation method of the present application simulates the echo considering the influence of the motion distance of the transceiver combined synthetic aperture sonar along the azimuth direction during the transmission and reception of signals, so that the echo simulated by the sonar echo simulation method of the present application is more close to the real condition of the transceiver combined synthetic aperture sonar.

[0056] Reference is made to the accompanying drawings Figure 9According to another aspect of the present application, the present application further provides a transceiver combined synthetic aperture sonar echo simulation system 100, wherein the sonar echo simulation system 100 comprises a first calculation unit 110, a second calculation unit 120, a third calculation unit 130, an echo signal acquisition unit 140, an iterative calculation unit 150 and a coherent accumulation unit 160, the first calculation unit 110, the second calculation unit 120, the third calculation unit 130, the echo signal acquisition unit 140, the iterative calculation unit 150 and the coherent accumulation unit 160 cooperate with each other, so that the simulated echo signal is closer to the actual motion of the transceiver combined synthetic aperture sonar, and the input echo closer to the actual motion can be provided for the transceiver combined synthetic aperture sonar signal processing software, which is beneficial to the improvement of the imaging performance of the long-distance target.

[0057] Specifically, the first calculation unit 110 is configured to calculate the transmission distance between the transceiver combined synthetic aperture sonar and a single target at the signal transmission time according to the two-dimensional coordinates of the transceiver combined synthetic aperture sonar at the signal transmission time and the two-dimensional coordinates of the single target. The second calculation unit 120 is configured to calculate the receiving distance between the transceiver combined synthetic aperture sonar and the single target at the echo signal receiving time according to the two-dimensional coordinates of the transceiver combined synthetic aperture sonar at the echo signal receiving time and the two-dimensional coordinates of the single target. The third calculation unit 130 is configured to calculate the accurate propagation time of the signal from the transmission to the receiving according to the transmission distance between the transceiver combined synthetic aperture sonar and the single target at the signal transmission time and the receiving distance between the transceiver combined synthetic aperture sonar and the single target at the echo signal receiving time. The echo signal acquisition unit 140 is configured to calculate the two-way distance of the signal according to the two-dimensional coordinates of the single target, the transmission distance between the transceiver combined synthetic aperture sonar and the single target at the signal transmission time and the receiving distance between the transceiver combined synthetic aperture sonar and the single target at the echo signal receiving time, delay process the transmitted modulated wideband signal to obtain the echo signal corresponding to the single target. The iterative calculation unit 150 is configured to transform the two-dimensional coordinates of the target and perform iterative calculation according to the above steps to obtain the echo signal corresponding to other arbitrary targets in the space. The coherent accumulation unit 160 is configured to perform coherent accumulation on the echo signals of all targets in the time domain, and then demodulate to obtain the baseband echo signal. Compared with the conventional transceiver combined synthetic aperture sonar echo simulation method, the sonar echo simulation system 100 of the present application considers the influence of the motion distance of the transceiver combined synthetic aperture sonar along the azimuth direction during the transmission and receiving of the signal, so that the simulated echo signal is closer to the actual motion of the transceiver combined synthetic aperture sonar, the input echo closer to the actual motion can be provided for the transceiver combined synthetic aperture sonar signal processing software, which is beneficial to the improvement of the imaging performance of the long-distance target.

[0058] Reference is made to the accompanying drawings Figure 10 According to another aspect of the present application, the present application further provides a computing device 200, wherein the computing device 200 comprises a processor 210 and a memory 220, and wherein the memory 220 stores computer program instructions which, when executed by the processor 210, cause the processor 210 to perform a sonar echo simulation method, wherein the sonar echo simulation method comprises the following steps: S1, calculating a transmission distance between a single target and a transceiver-repositioned synthetic aperture sonar at a signal transmission time according to a two-dimensional coordinate of the transceiver-repositioned synthetic aperture sonar at the signal transmission time and a two-dimensional coordinate of the single target; S2, calculating a receiving distance between the single target and the transceiver-repositioned synthetic aperture sonar at a signal receiving time according to a two-dimensional coordinate of the transceiver-repositioned synthetic aperture sonar at the signal receiving time and a two-dimensional coordinate of the single target; S3, calculating an accurate propagation time of the signal from the transmission to the receiving according to the transmission distance between the single target and the transceiver-repositioned synthetic aperture sonar at the signal transmission time and the receiving distance between the single target and the transceiver-repositioned synthetic aperture sonar at the signal receiving time; S4, calculating a two-way distance of the signal according to the two-dimensional coordinate of the single target, the transmission distance between the single target and the transceiver-repositioned synthetic aperture sonar at the signal transmission time, and the receiving distance between the single target and the transceiver-repositioned synthetic aperture sonar at the signal receiving time, and performing a delay processing on the transmitted modulated wideband signal to obtain an echo signal corresponding to the single target; S5, for any other target in space, performing an iterative calculation according to the above steps after transforming the two-dimensional coordinate corresponding to the target to obtain an echo signal corresponding to the any other target in space; and S6, performing a coherent accumulation on the echo signals of all targets in a time domain, and then performing a demodulation to obtain a baseband echo signal. Through the above steps, compared with a conventional transceiver-repositioned synthetic aperture sonar echo simulation method, the sonar echo simulation method of the present application considers an influence caused by a movement distance of the transceiver-repositioned synthetic aperture sonar along an azimuth direction during a signal transmission and receiving, so that the simulated echo signal is closer to a real movement condition of the transceiver-repositioned synthetic aperture sonar, and the input echo closer to the real movement condition can be provided for a signal processing software of the transceiver-repositioned synthetic aperture sonar, which is beneficial to improving an imaging performance of a long-distance target.

[0059] In one embodiment of the computing device 200 of the present application, the memory 220 can include one or more computer program products, which can include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory, for example, can include random access memory (RAM), cache memory, and / or the like. The non-volatile memory, for example, can include read-only memory (ROM), hard disk drives, solid-state drives, and / or the like. The computer-readable storage media can store one or more computer program instructions, which can be executed by the processor 210 to implement the functionality of the sonar echo simulation method of the present application described above.

[0060] In one embodiment of the computing device 200 of the present application, the processor 210 can be a central processing unit (CPU) or other form of processing unit having data processing and / or instruction execution capabilities, which can execute the program instructions stored on the computer-readable storage media to implement the functionality of the sonar echo simulation method of the present application described above.

[0061] In one embodiment of the computing device 200 of the present application, the computing device 200 can further include an input device 230 and an output device 240. The input device 230 can be, but is not limited to, a keyboard, a mouse, and the like. The output device 240 can be, but is not limited to, a display, a speaker, a printer, and the like. The input device 230 and the output device 240 can be connected to the processor 210 through a bus system.

[0062] Those skilled in the art should understand that the above-described embodiments and the drawings shown are only for illustratively explaining the present application, but not for limiting the present application. All equivalent embodiments, modifications, and improvements within the spirit of the present application should be included in the protection scope of the present application.

Claims

1. A method for simulating echoes from a combined transceiver synthetic aperture sonar, used to simulate echoes from a combined transceiver synthetic aperture sonar, characterized in that... The sonar echo simulation method includes the following steps: S1. Calculate the transmission distance between the transceiver synthetic aperture sonar and the single target based on the two-dimensional coordinates of the transceiver synthetic aperture sonar and the single target at the time of signal transmission. S2, calculate the receiving distance between the transceiver synthetic aperture sonar and the single target based on the two-dimensional coordinates of the transceiver synthetic aperture sonar and the target at the time of echo signal reception. S3. Calculate the precise propagation time of the signal from transmission to reception based on the transmission distance between the combined transceiver synthetic aperture sonar and the single target at the time of signal transmission and the reception distance between the combined transceiver synthetic aperture sonar and the single target at the time of echo signal reception. S4. Based on the two-dimensional coordinates of a single target, the transmission distance between the transceiver synthetic aperture sonar and the single target at the time of signal transmission, and the reception distance between the transceiver synthetic aperture sonar and the single target at the time of echo signal reception, calculate the two-way distance traversed by the signal, perform time delay processing on the transmitted modulated broadband signal, and obtain the echo signal corresponding to the single target. S5. For any other target in space, after transforming the two-dimensional coordinates corresponding to the target, perform iterative calculations according to the above steps to obtain the echo signal corresponding to any other target in space. S6. Coherently accumulate the echo signals of all targets in the time domain, and then demodulate them to obtain the baseband echo signal. In step S1, it is assumed that the system starts at the origin of the coordinate system, and after... After a certain time, at a certain speed The coordinates of the moving synthetic aperture sonar in the azimuth direction are: The coordinate of the target in the range direction is 0, and the coordinate of the target in the azimuth direction is... The coordinates in the distance direction are ,calculate At time t, the transmission distance between the combined transceiver synthetic aperture sonar and a single target at the signal transmission time. for: ; In step S2, it is assumed that the precise propagation time of the signal from transmission to reception is... With speed Motion-based synthetic aperture sonar with combined transmitter and receiver operates on the precise propagation time of signals from transmission to reception. The distance of the inner azimuth movement is At this point, the azimuth coordinates of the combined transceiver synthetic aperture sonar are: The receiving distance between the transceiver synthetic aperture sonar and a single target at the moment of echo signal reception. for: .

2. The method for simulating synthetic aperture sonar echoes using a combined transceiver setup according to claim 1, characterized in that, In step S3, the precise propagation time of the signal from transmission to reception is calculated. The corresponding propagation distance is equal to the sum of the transmission distance calculated in step S1 and the reception distance calculated in step S2, so the established equation is: ,in Let represent the speed of sound in water. By solving the above equation, the precise propagation time of the signal from transmission to reception is obtained as follows: The precise expression is: .

3. The method for simulating synthetic aperture sonar echoes using a combined transceiver setup according to claim 2, characterized in that, In step S4, the transmission distance between the combined transmit / receive synthetic aperture sonar and the single target at the signal transmission moment is: The receiving distance between the transceiver synthetic aperture sonar and the single target at the moment of echo signal reception is: The two-way distance traversed by the signal is obtained as follows: Assuming Indicates frequency modulation. This indicates the fast time corresponding to the distance direction. Indicates the carrier frequency; the transmitted wideband signal is a linear frequency modulated signal. Then the modulated transmitted signal is After delay processing, the echo signal is obtained. The expression is: ,in It represents the imaginary unit.

4. The method for simulating synthetic aperture sonar echoes using a combined transceiver setup according to claim 3, characterized in that, In step S5, it is assumed that the coordinates of any other target in space in the azimuth direction are... The coordinates in the distance direction are The two-way distance traversed by the signal is calculated according to step S4 as follows: Correspondingly, the echo signal corresponding to this target is: .

5. The method for simulating synthetic aperture sonar echoes using a combined transceiver setup according to claim 4, characterized in that, In step S6, the expression for coherent accumulation is: The total number of targets is Then, the coherently accumulated echo signal is demodulated, as expressed by: .

6. A combined transceiver synthetic aperture sonar echo simulation system, used for performing echo simulation of combined transceiver synthetic aperture sonar based on the method described in claim 1, characterized in that, include: The first calculation unit is used to calculate the transmission distance between the transceiver synthetic aperture sonar and the single target based on the two-dimensional coordinates of the transceiver synthetic aperture sonar and the two-dimensional coordinates of the single target at the time of signal transmission. The second calculation unit is used to calculate the receiving distance between the transceiver synthetic aperture sonar and a single target based on the two-dimensional coordinates of the transceiver synthetic aperture sonar and the target at the time of echo signal reception. The third calculation unit is used to calculate the precise propagation time of the signal from transmission to reception based on the transmission distance between the transceiver synthetic aperture sonar and a single target at the time of signal transmission and the reception distance between the transceiver synthetic aperture sonar and a single target at the time of echo signal reception. The echo signal acquisition unit is used to calculate the two-way distance traversed by the signal based on the two-dimensional coordinates of a single target, the transmission distance between the transceiver synthetic aperture sonar and the single target at the time of signal transmission, and the reception distance between the transceiver synthetic aperture sonar and the single target at the time of echo signal reception. It also performs time delay processing on the transmitted modulated broadband signal to obtain the echo signal corresponding to the single target. The iterative calculation unit is used to perform iterative calculations on any other target in space after transforming the two-dimensional coordinates of the target, and then following the steps above to obtain the echo signal corresponding to any other target in space. The coherent accumulation unit is used to coherently accumulate the echo signals of all targets in the time domain, and then demodulate them to obtain the baseband echo signal.

7. The synthetic aperture sonar echo simulation system with combined transceiver configuration according to claim 6, characterized in that, Assuming the system starts at the origin, after which... After a certain time, at a certain speed The coordinates of the moving synthetic aperture sonar in the azimuth direction are: The coordinate of the target in the range direction is 0, and the coordinate of the target in the azimuth direction is... The coordinates in the distance direction are The first computing unit calculates At time t, the transmission distance between the combined transceiver synthetic aperture sonar and a single target at the signal transmission time. for: .

8. A computing device, characterized in that, It includes a processor and a memory, wherein computer program instructions are stored in the memory, and when the computer program instructions are executed in the processor, the processor causes the processor to perform the sonar echo simulation method as described in any one of claims 1 to 5.

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