A device and method for in-situ calibration of the amplitude and phase response of a passive sonar array

Abstract

The present application belongs to the technical field of underwater acoustic positioning, and provides a passive sonar array amplitude-phase response field in-situ calibration device and method, which comprises the following steps: sound source and array arrangement, distance measurement, angle determination, sound source level determination, amplitude response calibration, and phase response calibration; the relative position of the sound source and the array is determined through water surface end time synchronization and underwater acoustic distance measurement, and an underwater calibration operation scheme convenient for engineering implementation is constructed; the sound source is arranged in the near field of the sonar array to be calibrated, near field measurement can effectively ensure the accuracy of distance measurement and positioning, and the phase parameters are corrected by using the distance measurement results of each array element of the array, so that the far field phase response of each array element of the array can be calculated in the near field measurement environment, and the requirement for the space of the test water area is reduced; through the field in-situ calibration scheme, normal operation and maintenance can be realized, the parameters of the sonar array equipment during the in-service period can be controlled and traced, and the detection performance of the sonar array is effectively guaranteed.

Description

Technical Field

[0001] This invention relates to the field of underwater acoustic positioning technology, and in particular to a passive sonar array amplitude and phase response in-situ calibration device and method. Background Technology

[0002] Sound waves are the only effective carrier for long-distance underwater information transmission. Passive sonar arrays, composed of multiple regularly arranged hydrophones, can achieve spatial directivity and signal-to-noise ratio gain through beamforming technology, and can also achieve target direction finding, thus becoming the core equipment for underwater target detection. The amplitude response of a passive sonar array is the amplitude sensitivity of each element to far-field incident sound waves of different azimuths and frequencies, while the phase response is the phase shift of each element receiving far-field incident sound waves of different azimuths and frequencies. Both are collectively referred to as the array amplitude-phase response. Passive sonar array beamforming is the process of matching and analyzing the array amplitude-phase response parameters with the multi-channel data actually received by the array. The array amplitude-phase response is the basis of array beamforming and the source of array directivity and spatial gain, determining the array's beamwidth, signal gain, direction finding accuracy, and detection range. Traditionally, the design values ​​of the array amplitude and phase response are calculated based on the sensitivity calibration results of individual array elements and the element position calibration results, serving as preset parameters for the sonar signal processing system. However, due to the influence of acoustic scattering and coupling from the passive sonar array carrier platform, the actual amplitude and phase response deviates significantly from the design values. Furthermore, the array operates underwater for extended periods, and is susceptible to drift due to carrier platform vibration, water flow impact, and aging of piezoelectric materials. These deviations in the array amplitude and phase response severely affect beamforming performance, causing main lobe broadening and shift, and side lobe lifting, resulting in a significant decrease in the array's directivity, direction finding accuracy, and detection range. Therefore, conducting in-situ calibration of the passive sonar array's amplitude and phase response is crucial for ensuring the array's detection performance. Calibration of the passive sonar array's amplitude and phase response requires a relatively large aquatic environment; only small high-frequency arrays can be calibrated in laboratory pools. For fixed passive sonar arrays mounted on underwater platforms, disassembly is extremely inconvenient once assembled and deployed, making it difficult to transport them ashore for calibration. Therefore, the amplitude and phase response calibration of fixed passive sonar arrays must be conducted in-situ in lakes or oceans. Existing field array amplitude and phase response calibration schemes for pools or lakes involve fixing the array to be calibrated to a lifting and rotating mechanism, placing a sound source at a specific location in the water, and controlling the lifting and rotating mechanism to stepwise adjust the rotation angle of the array to be calibrated in order to obtain the array amplitude and phase response in different orientations while keeping the sound source fixed.

[0003] However, for large-aperture, heavy sonar arrays integrated with the mounting platform, the lifting and rotating mechanism cannot effectively dock, fix, and accurately rotate with the equipment being calibrated, making it impossible to determine the relative positional relationship between the array and the sound source. Large arrays have long far-field distances, often failing to meet far-field conditions during calibration, and near-field calibration suffers from significant phase calibration errors due to spherical wavefront distortion. CN120065127A proposes a method and system for calibrating the position and phase errors of an ultra-short baseline array. It uses the azimuth angle between the sound source and the array being calibrated as a known quantity and assumes that the inherent phase deviation of each element does not change with the azimuth angle of the incoming wave, i.e., it is a constant value. However, the above assumptions are not applicable to the calibration of large passive sonar arrays in lake and sea environments. On the one hand, large passive sonar arrays are usually integrated with the underwater platform / vehicle they are mounted on, making it difficult to fix and accurately adjust their angles using a lifting and rotating mechanism; on the other hand, the acoustic coupling effect between the array and the carrier platform is related to the direction of the incoming wave, meaning that the inherent phase deviation of each element changes with the azimuth of the incoming wave. Furthermore, this technology requires the distance between the sound source and the array to meet far-field conditions, and cannot correct or compensate for near-field effects. Regarding amplitude response calibration, this technology can only provide the amplitude gain factor of each array element relative to the reference array element, and cannot provide the absolute amplitude response of each element. In summary, this technology cannot meet the on-site calibration requirements for the amplitude and phase response of large passive sonar arrays after installation. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the purpose of this invention is to provide a passive sonar array amplitude and phase response in-situ calibration device and method, which solves the problem that passive sonar arrays are difficult to disassemble and send ashore for inspection and calibration after installation.

[0005] To achieve the above objectives, the present invention provides the following solution: A passive sonar array amplitude and phase response in-situ calibration device includes: a standard sound source, a surface auxiliary vessel, a surface platform, and a sonar array to be calibrated; the standard sound source includes: an underwater wet-end and a surface host computer connected via a serial communication cable; the underwater wet-end integrates a standard hydrophone; depth sensors are installed at the central reference element of the sonar array to be calibrated and at the underwater wet-end; the surface platform carries an array data processing system; the surface host computer and the surface platform are equipped with GNSS receivers; The underwater wet end is fixed below the surface auxiliary vessel; the surface host computer end is fixed on the surface auxiliary vessel; the array data processing system is connected to the sonar array under calibration and the depth sensor on the sonar array under calibration via cables. The GNSS receiver is used to synchronize the standard sound source and the sonar array under calibration using the BeiDou second pulse; the surface host computer is used to control the underwater wet end to transmit sound signals on the rising edge of the BeiDou second pulse of the GNSS receiver; the sonar array under calibration is used to receive the sound signals and upload them to the array data processing system; the array data processing system is used to perform amplitude response calibration and phase response calibration on the sonar array under calibration.

[0006] A method for in-situ calibration of the amplitude and phase response of a passive sonar array, comprising: S1: Deploy the standard sound source and the sonar array to be calibrated at a set depth underwater; S2: Using the standard sound source to emit high-frequency short pulses, the distance measurement and time synchronization are performed by using the time difference between the signal reception time and the signal transmission time of each element of the sonar array under calibration, and the distance measurement result is obtained. S3: Determine the elevation and horizontal angles of the standard sound source based on the ranging results and the coordinates of each element of the sonar array being calibrated; S4: Control the standard sound source to emit a sinusoidal pulse according to the set sound signal frequency, determine the voltage amplitude according to the signal waveform received by the standard hydrophone, and determine the sound source level according to the voltage amplitude and the standard hydrophone sensitivity value; S5: Determine the absolute sound pressure amplitude based on the signal waveforms received by each element of the sonar array being calibrated; calculate the absolute sound pressure amplitude, the sound source level, and the ranging result using the sensitivity formula based on the elevation angle and the horizontal angle to obtain the amplitude sensitivity. S6: The phase of each element is calculated using the signal waveform received by each element of the sonar array under calibration to obtain the initial element phase. The initial element phase is then corrected for near-field effect using the near-field correction formula to obtain the equivalent far-field phase. S7: Change the frequency of the sound signal and repeat steps S4 to S6; Move the auxiliary vessel to the next measurement position and repeat steps S2 to S7 to obtain calibration results of array amplitude and phase response under different azimuths and frequencies.

[0007] Preferably, the standard sound source emits high-frequency short pulses, and the ranging is performed using the time difference between the signal reception time and the signal transmission time of each element of the sonar array under calibration, to obtain the ranging result, including: The host computer on the water surface controls the underwater wet end to emit high-frequency short pulses, and the array data processing system receives the waveforms of each element of the sonar array being calibrated. Peak detection is performed on the waveforms of each array element to obtain the propagation time of the sound source emitted signal to each array element; The propagation distance is calculated based on the speed of sound and the propagation time to obtain the ranging result.

[0008] Preferably, determining the elevation and horizontal angles of the standard sound source based on the ranging results and the coordinates of each element of the sonar array being calibrated includes: A set of distance equations is constructed based on the ranging results and the coordinates of each array element. The coordinates of the sound source are obtained by solving the distance equations using the least squares method. The pitch angle and the horizontal angle are determined based on the coordinates of the sound source.

[0009] Preferably, the expression for the sound source level is: ;in, For the emission source level; This is the amplitude measurement value; The distance between the standard hydrophone and the sound center of the sound source; This is the standard hydrophone sensitivity value.

[0010] Preferably, the expression for the absolute sound pressure amplitude of the m-th array element is: ;in, This is the absolute sound pressure level. This is the measured value of the voltage amplitude of a standard hydrophone. The distance between the standard hydrophone and the sound center of the sound source; This is the standard hydrophone sensitivity value; Let m be the distance between the m-th array element and the sound source.

[0011] Preferably, the sensitivity formula for the m-th array element is: ;in, Amplitude sensitivity; The amplitude of the array element's output voltage waveform; This is the standard hydrophone sensitivity value; The distance between the m-th array element and the sound source; This is the measured value of the voltage amplitude of a standard hydrophone. The distance between the standard hydrophone and the sound center of the sound source.

[0012] Preferably, the near-field correction formula is: ;in, This is the equivalent far-field phase; Near-field phase; , , These are the x-coordinate, y-coordinate, and vertical coordinate of the array element, respectively. , These are the pitch angle and the horizontal angle, respectively. The distance between the m-th array element and the center of the sound source; λ is the wavelength.

[0013] The present invention discloses the following technical effects: This invention provides a passive sonar array amplitude and phase response in-situ calibration device and method. By employing a fixed array deployment and a mobile measurement method using an omnidirectional standard sound source mounted on a surface auxiliary vessel, it solves the problem of existing technologies' difficulty in fixing and accurately adjusting angles using lifting and rotating mechanisms. This enables in-situ calibration of fixed arrays of different sizes and apertures without disassembling the array. By converting near-field measurement results under spherical wavefront distortion into an equivalent far-field phase response through near-field acoustic ranging and geometric phase correction, it solves the problem of large-size arrays failing to meet far-field conditions, achieving accurate far-field amplitude and phase characteristics within limited water areas. By integrating a standard hydrophone with the standard sound source to monitor the sound source level in real time and calculating the absolute sound pressure at the array element based on the propagation distance, it overcomes the limitation of traditional methods only providing relative amplitude gain, achieving precise measurement of the absolute amplitude response of each array element. By using BeiDou second pulse time synchronization and acoustic pulse ranging, combined with the known coordinates of the array to solve for the sound source azimuth, it solves the problem of inaccurate underwater sound source azimuth determination and positioning, achieving non-contact automatic azimuth calibration and avoiding complex mechanical angle stepping devices. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 A schematic diagram of an in-situ calibration device for the amplitude and phase response of a passive sonar array provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the array local coordinate system provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the timing of the sound source emission signal provided in an embodiment of the present invention; Figure 4 This is a schematic diagram illustrating the phase calculation principle provided in an embodiment of the present invention. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] The purpose of this invention is to provide a passive sonar array amplitude and phase response in-situ calibration device and method, which solves the problem that passive sonar arrays are difficult to disassemble and send ashore for inspection and calibration after installation.

[0018] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] Figure 1 This is a schematic diagram of an in-situ calibration device for the amplitude and phase response of a passive sonar array provided in an embodiment of the present invention, as shown below. Figure 1 As shown, this invention provides an in-situ calibration device for the amplitude and phase response of a passive sonar array, comprising: a standard sound source, a surface auxiliary vessel, a surface platform, and a sonar array to be calibrated; the standard sound source includes: an underwater wet end and a surface host computer connected via a serial communication cable; the underwater wet end integrates a standard hydrophone; a depth sensor is installed at the center reference element of the sonar array to be calibrated and at the underwater wet end; the surface platform carries an array data processing system; the surface host computer and the surface platform are equipped with GNSS receivers; The underwater wet end is fixed below the surface auxiliary vessel; the surface host computer end is fixed on the surface auxiliary vessel; the array data processing system is connected to the sonar array under calibration and the depth sensor on the sonar array under calibration via cables. The GNSS receiver is used to synchronize the standard sound source and the sonar array under calibration using the BeiDou second pulse; the surface host computer is used to control the underwater wet end to transmit sound signals on the rising edge of the BeiDou second pulse of the GNSS receiver; the sonar array under calibration is used to receive the sound signals and upload them to the array data processing system; the array data processing system is used to perform amplitude response calibration and phase response calibration on the sonar array under calibration.

[0020] Preferably, this embodiment proposes an in-situ calibration device and method for the amplitude and phase response of a passive sonar array. This embodiment employs a scheme where the array to be calibrated is fixedly deployed, and a surface auxiliary vessel carries an omnidirectional standard sound source for mobile measurement. This allows for in-situ calibration of fixed arrays of different sizes and aperture scales without disassembling the array. This embodiment uses acoustic ranging based on BeiDou second-pulse synchronization, combining the coordinate position information of each array element to establish an array coordinate system and accurately calibrate the azimuth of the sound source within this coordinate system. This embodiment utilizes the ranging results from the sound source to each array element to perform amplitude and phase response measurement calculation and compensation correction, including: calculating the sound pressure level at each array element by combining the standard sound source level and the sound signal propagation distance, thereby obtaining the absolute amplitude response; calculating the phase measurement deviation introduced by near-field spherical wave spread based on the propagation distance and azimuth angle, and correcting the near-field phase response to the far-field phase response. Ultimately, this achieves in-situ calibration of the amplitude and phase response of the passive sonar array.

[0021] Specifically, the sonar array to be calibrated is fixed (secured to the surface platform via connecting rods or anchored to its carrier platform). A standard sound source, carried by a surface auxiliary vessel, is maneuvered along a specific trajectory. The sound source consists of an underwater wet-end and a surface-mounted host computer, connected by a serial communication cable. The wet-end integrates a standard hydrophone for sound pressure monitoring and is equipped with a depth (pressure) sensor. The host computer is equipped with a GNSS receiver. A depth sensor is installed at the central reference element of the array to be calibrated. The surface platform housing the array to be calibrated carries an array data processing system, connected to the array and depth sensor via cables, and also equipped with a GNSS receiver. During the experiment, the host computer uses the BeiDou second pulse from its integrated GNSS receiver as a time reference. At the rising edge of the second pulse, it controls the underwater wet-end of the sound source to transmit sound signals via RS485 serial communication. The transmitted sound signals are collected by the array to be calibrated and uploaded to the array data processing system. The array data processing system uses the rising edge of the BeiDou second pulse from its GNSS receiver as a trigger to receive signals from each array element. The above method enables the sound source transmitter and the array receiver to share the time reference of the BeiDou satellite navigation system, thus achieving time synchronization. A schematic diagram of the calibration device is shown below. Figure 1 .

[0022] Furthermore, ranging and sound source location determination: This embodiment primarily focuses on fixed passive sonar arrays, specifically calibrating the coordinates of each array element during the assembly process. During actual calibration, the host computer at the surface end of the sound source controls the underwater wet end to transmit high-frequency short-pulse signals, while the array data processing system synchronously receives the waveforms from each element. Time synchronization is achieved between the two systems based on the BeiDou second-pulse mode, and the propagation time from the sound source's transmitted signal to each array element is obtained through peak detection. The propagation distance is calculated by combining the speed of sound, c. .by Figure 2Taking the arbitrary sonar array shown as an example, the three-dimensional coordinates of each array element are: It should be noted that this coordinate system is a local coordinate system with the array elements themselves as reference points, not a geodetic coordinate system. The coordinates of each element can be obtained during the assembly stage through laser tracking or reciprocal polling. Based on the coordinates of each element and the propagation distance from the sound source to each element, the following set of distance equations can be established: .

[0023] Subtracting the equations one by one to eliminate the quadratic terms, we obtain the following system of linear equations: .

[0024] The above system of equations is solved using the least squares method, and the coordinates of the sound source are obtained. It can be calculated as: .

[0025] in , .

[0026] Sound source pitch angle The angle between the line connecting the sound source and the origin and the horizontal plane (xoy plane) of the coordinate system is calculated as follows: .

[0027] The range of pitch angle values ​​is: Horizontal angle of sound source The angle between the projection of the line connecting the sound source and the origin onto the horizontal plane of the coordinate system and the x-axis of the coordinate system is calculated as follows: .

[0028] The range of values ​​for the horizontal angle is: .for In the case of, if ,but ,like ,but .

[0029] Preferably, amplitude response calibration: Amplitude response is the response of each array element to different orientations. Different frequencies Amplitude sensitivity of incident sound wave Amplitude sensitivity is defined as the ratio of the amplitude of the output voltage waveform of the array element to the amplitude of the sound pressure at the location of the array element. .

[0030] The amplitude response calibration process is as follows: the auxiliary vessel carrying the sound source maneuvers along a set trajectory and conducts measurements at several selected fixed locations. The sound source emission is as follows: Figure 3 The combined measurement signal shown is an alternating transmission of high-frequency ranging pulses and sinusoidal measurement signals of different frequencies.

[0031] Distance from the sound source center A standard hydrophone receives the above sinusoidal signal and provides a voltage amplitude measurement. The amplitude sensitivity of a standard hydrophone is The emission level of the sound source is then calculated as follows: Combining the sound source level and the distance between the m-th array element and the sound source The absolute sound pressure amplitude at the location of the array element can be calculated. Combined with the amplitude of the array element output voltage waveform Calculate the amplitude sensitivity of this array element. The sensitivity formula is: .

[0032] After the calculation is complete, take 20 times the logarithm to the base 10 and convert it to a decibel value.

[0033] By moving the sound source position, different pitch and horizontal orientations were measured. The amplitude sensitivity of each element in the array is the array amplitude response.

[0034] Furthermore, phase response calibration: refer to Figure 4 The waveform sequence received by each array element is as follows The phase parameters of each array element are calculated using Discrete Fourier Transform. Taking the m-th array element as an example, a set of sinusoidal sequences with the same frequency as the transmitted signal is first generated, and then the inner product of the waveform sequence and the sinusoidal sequence (i.e., the cross-correlation) is calculated. .

[0035] Then the phase of the m-th element is: .

[0036] Unlike the amplitude response, which uses the absolute sound pressure level as a reference, the phase response requires a specific array element as a reference. Here, we use the first array element at the origin of the array coordinate system as the reference element. Then, the phase of the m-th array element is expressed as: .

[0037] The phase response of each array element includes two components: the geometric phase component caused by the difference in sound propagation path at different spatial locations, and the phase deviation of each element itself caused by factors such as acoustic coupling and delay of the array element acquisition module. If the distance between the sound source and the array being calibrated satisfies the far-field condition, i.e. ( (where is the aperture of the array). The incident sound wave exhibits a plane wave distribution at each array element. At this time, the geometric phase difference between the m-th array element and the reference array element (the origin of the coordinate system) is: .

[0038] If the distance between the sound source and the array being calibrated does not meet the far-field condition, the incident sound wave will exhibit spherical wave propagation at each array element. In this case, the geometric phase difference should be calculated based on the path difference of the incident sound wave, i.e., the geometric phase difference between the m-th array element and the reference array element is... , The wavelength is used. Therefore, this embodiment proposes to perform geometric phase correction on the near-field measurement results to convert them to the equivalent far-field, and the equivalent far-field phase... With near-field phase The correction formula between the two fields (i.e., the near-field correction formula) is as follows: .

[0039] By moving the sound source position, different pitch and horizontal orientations were measured. The equivalent far-field phase of each element in the lower array is the array phase response.

[0040] Specifically, the implementation process of the technical solution in this embodiment is as follows: 1) The auxiliary vessel carries a standard sound source, and the surface fixed platform is connected to the sonar array to be calibrated (or the sonar array carrier platform is anchored). The deployment depth of both is monitored and controlled by a depth sensor. 2) The sound source emits high-frequency short pulses, and the distance is measured based on the time difference between the signal reception time and the signal transmission time of each array element, combined with the speed of sound in water; 3) Calculate the current pitch and horizontal angles of the sound source based on the ranging results and the coordinates of each array element; 4) Set the frequency of the sound signal, the sound source emits a sinusoidal pulse, the standard hydrophone integrated in the sound source receives the sound signal and outputs a voltage signal waveform, calculate the voltage signal amplitude, and give the sound source level in combination with the standard hydrophone sensitivity value; 5) Calculate the voltage amplitude of the received signal waveforms of each array element, and calculate the amplitude sensitivity using the sensitivity formula, taking into account the sound source level and the distance from the sound source to each array element. 6) Based on the signal waveforms received by each array element, calculate the phase of each element, and use the near-field correction formula to correct the near-field effect, and calculate the equivalent far-field phase. 7) Change the frequency of the sound signal and repeat steps 4) to 6); 8) The auxiliary vessel moves to the next measurement position and repeats steps 2) to 7) to obtain the calibration results of the array amplitude and phase response under different azimuths and frequencies.

[0041] Optionally, for small sonar arrays, either the technical solution of this embodiment can be used, or a solution using a lifting and rotating mechanism to carry a passive sonar array for angle step measurement and calibration can be used. However, for large sonar arrays and underwater platforms, amplitude and phase response calibration can only use the technical solution of this embodiment.

[0042] The underwater distance and relative azimuth information can also be calculated using the position coordinate information of the surface satellite positioning system. However, considering that the azimuth projection of the underwater end of the sound source and the array reference point with their respective surface ends is difficult to control accurately, and factors such as water surface fluctuations are unavoidable during field tests, the underwater acoustic ranging method adopted in this embodiment has higher accuracy and environmental adaptability.

[0043] The beneficial effects of this invention are as follows: (1) The accuracy of the amplitude and phase response parameters of a passive sonar array determines the array's detection performance against underwater targets. This invention addresses the problem that large fixed passive sonar arrays are difficult to disassemble and cannot be loaded by a surface rotation mechanism. It proposes an on-site calibration method for the array amplitude and phase response by anchoring the target object and measuring the motion of the sound source. The relative position of the sound source and the array is determined by surface time synchronization and underwater acoustic ranging, thus constructing an underwater calibration operation scheme that is easy to implement in engineering.

[0044] (2) The present invention places the sound source in the near field of the sonar array to be calibrated. Near field measurement can effectively ensure the accuracy of ranging and positioning. At the same time, the phase parameters are corrected by using the ranging results of each array element. The equivalent far field phase response of each array element can be calculated under near field measurement conditions, which reduces the requirements for the test water space.

[0045] (3) As an on-site calibration scheme, this invention can realize routine operation and maintenance, ensure that the parameters of the sonar array equipment are controllable and traceable during service, and ensure the underwater detection performance of the sonar array.

[0046] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0047] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A passive sonar array amplitude and phase response in-situ calibration device, characterized in that, include: Standard sound source, surface auxiliary vessel, surface platform, sonar array to be calibrated; The standard sound source includes: an underwater wet end and a surface host computer connected via a serial communication cable; the underwater wet end integrates a standard hydrophone; a depth sensor is installed at the center reference element of the sonar array being calibrated and at the underwater wet end; the surface platform is equipped with an array data processing system; the surface host computer and the surface platform are equipped with GNSS receivers. The underwater wet end is fixed below the surface auxiliary vessel; the surface host computer end is fixed on the surface auxiliary vessel; the array data processing system is connected to the sonar array under calibration and the depth sensor on the sonar array under calibration via cables. The GNSS receiver is used to synchronize the standard sound source and the sonar array under calibration using the BeiDou second pulse; the surface host computer is used to control the underwater wet end to transmit sound signals on the rising edge of the BeiDou second pulse of the GNSS receiver; the sonar array under calibration is used to receive the sound signals and upload them to the array data processing system; the array data processing system is used to perform amplitude response calibration and phase response calibration on the sonar array under calibration.

2. A method for in-situ calibration of the amplitude and phase response of a passive sonar array, characterized in that, The passive sonar array amplitude and phase response in-situ calibration device according to claim 1 includes: S1: Deploy the standard sound source and the sonar array to be calibrated at a set depth underwater; S2: Using the standard sound source to emit high-frequency short pulses, the distance measurement and time synchronization are performed by using the time difference between the signal reception time and the signal transmission time of each element of the sonar array under calibration, and the distance measurement result is obtained. S3: Determine the elevation and horizontal angles of the standard sound source based on the ranging results and the coordinates of each element of the sonar array being calibrated; S4: Control the standard sound source to emit a sinusoidal pulse according to the set sound signal frequency, determine the voltage amplitude according to the signal waveform received by the standard hydrophone, and determine the sound source level according to the voltage amplitude and the standard hydrophone sensitivity value; S5: Determine the absolute sound pressure amplitude based on the signal waveforms received by each element of the sonar array being calibrated; calculate the absolute sound pressure amplitude, the sound source level, and the ranging result using the sensitivity formula based on the elevation angle and the horizontal angle to obtain the amplitude sensitivity. S6: The phase of each element is calculated using the signal waveform received by each element of the sonar array under calibration to obtain the initial element phase. The initial element phase is then corrected for near-field effect using the near-field correction formula to obtain the equivalent far-field phase. S7: Change the frequency of the sound signal and repeat steps S4 to S6; Move the auxiliary vessel to the next measurement position and repeat steps S2 to S7 to obtain calibration results of array amplitude and phase response under different azimuths and frequencies.

3. The passive sonar array amplitude and phase response in-situ calibration method according to claim 2, characterized in that, The standard sound source emits high-frequency short pulses, and the ranging is performed using the time difference between the signal reception time and the signal transmission time of each element of the sonar array under calibration, to obtain the ranging result, including: The host computer on the water surface controls the underwater wet end to emit high-frequency short pulses, and the array data processing system receives the waveforms of each element of the sonar array being calibrated. Peak detection is performed on the waveforms of each array element to obtain the propagation time of the sound source emitted signal to each array element; The propagation distance is calculated based on the speed of sound and the propagation time to obtain the ranging result.

4. The passive sonar array amplitude and phase response in-situ calibration method according to claim 2, characterized in that, Determining the elevation and horizontal angles of the standard sound source based on the ranging results and the coordinates of each element of the sonar array being calibrated includes: A set of distance equations is constructed based on the ranging results and the coordinates of each array element. The coordinates of the sound source are obtained by solving the distance equations using the least squares method. The pitch angle and the horizontal angle are determined based on the coordinates of the sound source.

5. The passive sonar array amplitude and phase response in-situ calibration method according to claim 2, characterized in that, The expression for the sound source level is: ;in, For the emission source level; This is the amplitude measurement value; The distance between the standard hydrophone and the sound center of the sound source; This is the standard hydrophone sensitivity value.

6. The passive sonar array amplitude and phase response in-situ calibration method according to claim 2, characterized in that, The expression for the absolute sound pressure amplitude of the m-th array element is: ;in, This is the absolute sound pressure level. This is the measured value of the voltage amplitude of a standard hydrophone; The distance between the standard hydrophone and the sound center of the sound source; This is the standard hydrophone sensitivity value; Let m be the distance between the m-th array element and the sound source.

7. The passive sonar array amplitude and phase response in-situ calibration method according to claim 2, characterized in that, The sensitivity formula for the m-th array element is: ;in, Amplitude sensitivity; The amplitude of the output voltage waveform of the array element; This is the standard hydrophone sensitivity value; Let m be the distance between the m-th array element and the sound source; This is the measured value of the voltage amplitude of a standard hydrophone; The distance between the standard hydrophone and the sound center of the sound source.

8. The passive sonar array amplitude and phase response in-situ calibration method according to claim 2, characterized in that, The near-field correction formula is as follows: ;in, This is the equivalent far-field phase; Near-field phase; , , These are the x-coordinate, y-coordinate, and vertical coordinate of the array element, respectively. , These are the pitch angle and the horizontal angle, respectively. The distance between the m-th array element and the center of the sound source; λ is the wavelength.

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