An underwater acoustic imaging shipboard information processing and display control system

Abstract

The application provides a kind of underwater acoustic imaging shipboard information processing and display control system, it is related to underwater acoustic imaging technical field, including core control unit, acoustic emission unit, data acquisition unit, environmental perception auxiliary unit and positioning unit, the control terminal is connected through gigabit network super imaging signal generator, the super imaging signal generator is connected two power amplifier units through sixteen channels, each power amplifier unit distributes eight channels, and each power amplifier unit is connected eight transducers.The application solves the problems of poor environmental adaptability, serious beam defocusing and weak fault recovery capability of traditional fixed array underwater acoustic imaging system in complex water area through environmental adaptive algorithm and mechanical-electronic cooperative regulation mechanism.

Description

Technical Field

[0001] This invention relates to the field of underwater acoustic imaging technology, and in particular to an underwater acoustic imaging shipborne information processing and display control system. Background Technology

[0002] Shipborne underwater acoustic imaging is a technology that utilizes the propagation characteristics of sound waves in water to perform high-resolution detection and imaging of underwater environments or targets through an acoustic system mounted on a ship. Its core involves emitting sound wave signals through a transducer array, receiving reflected waves, and combining multi-source data for signal processing and beamforming to generate visualized images of underwater terrain, targets, or structures. It is widely used in fields such as marine resource exploration, shipwreck salvage, underwater pipeline monitoring, and military target identification.

[0003] Existing technologies mostly rely on single electronic beamforming or static array design, which cannot dynamically correct sound velocity gradients. For example, salinity gradients can cause ±5% sound velocity deviations, mismatch between array element spacing and water depth can lead to grating lobe interference, and sidelobe suppression ratios are only -15dB. When ships pass through special waters, such as the confluence of fresh and seawater or uneven water turbidity, there is a problem of reduced underwater acoustic imaging performance. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies. This invention significantly overcomes the problems of imaging blurring and positioning deviation caused by sudden changes in sound velocity gradient and interference from suspended objects in complex waters by dynamically adjusting the physical array of transducers, real-time sound velocity correction and electromechanical coordinated beamforming. At the same time, it introduces a multi-level fault-tolerant mechanism to ensure continuous operation under extreme conditions, and finally achieves stable detection effect in turbid waters.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a shipborne information processing and display control system for underwater acoustic imaging, comprising:

[0006] The core control unit includes a command and control terminal and a phased array control host computer;

[0007] An acoustic emission unit, comprising a frequency division imaging signal generator, a movable power amplifier track module, and a phased array sound source;

[0008] The data acquisition unit includes a four-channel acquisition unit and a hydrophone module;

[0009] An environmental perception auxiliary unit, which includes a multi-parameter water quality sensor and an acoustic detection and acquisition unit;

[0010] The positioning unit includes a GPS module and an inertial navigation module;

[0011] The movable power amplifier track module includes a movable track, a track servo controller, a track motor driver, and an elevation motor driver. The movable track is used to mount the transducer array on the hull. The track servo controller is signal-connected to the track motor driver and the elevation motor driver.

[0012] The phased array sound source includes a power amplifier unit and a transducer array, the transducer array includes sixteen transducers, and the transducers receive electrical signals from the power amplifier unit.

[0013] The command and control terminal is connected to the super-resolution imaging signal generator via a 10 Gigabit network. The super-resolution imaging signal generator is connected to two power amplifier units via sixteen channels. Each power amplifier unit is allocated eight channels, each power amplifier unit is connected to eight transducers, and each transducer is connected to one channel.

[0014] The command and control terminal is connected to the phased array control host computer via a 10 Gigabit network, and the phased array control host computer is connected to the hydrophone and the four-channel acquisition unit via two gigabit networks respectively.

[0015] The command and control terminal is connected to the track servo controller via shielded twisted pair cable, and the track servo controller is connected to the track motor driver and the elevation motor driver via CAN bus.

[0016] The command and control terminal is connected to a digital oscilloscope via a USB 3.0 channel, and the probe of the digital oscilloscope is connected to a hydrophone.

[0017] The command and control terminal is connected to the data storage server via optical fiber, and the data storage server is connected to the acoustic detection acquisition unit and the multi-parameter water quality sensor data via a SAS interface.

[0018] The command and control terminal is connected to the GPS module via RS232, and the command and control terminal is connected to the inertial navigation module via a 10 Gigabit network.

[0019] In a preferred embodiment, the command and control terminal is equipped with an environment adaptive algorithm for multi-source data fusion processing, global task scheduling, and human-computer interaction interface rendering; the phased array control host computer receives hydrophone data in real time, calculates sound source channel delay parameters, and controls the signal generator and power amplifier unit; the super-resolution imaging signal generator generates frequency-adjustable / phase-adjustable transmission signals and receives delay parameters from the phased array control host computer and outputs them in separate channels; the movable power amplifier track module adjusts the element spacing of the phased array sound source according to water quality changes and adapts the array tilt of the phased array sound source to different water depths. Elevation angle; the transducer array is used to convert electrical signals into sound waves, and the spatial layout of the transducer array can be changed when the movable power amplifier track module receives mechanical adjustment commands; the four-channel acquisition unit is used to synchronously acquire transponder signals and transmit time difference data to the core control unit in real time; the hydrophone module is used to receive reflected sound wave signals and provide raw acoustic data for imaging; the multi-parameter water quality sensor is used to provide real-time feedback of aquatic environment data and trigger adaptive algorithm parameter updates; the acoustic detection acquisition unit is used to monitor the direct wave of the phased array sound source and provide beam pointing calibration data.

[0020] As a preferred embodiment, the environmental adaptive adjustment algorithm is used to optimize the array configuration of the phased array acoustic source based on the detected water quality data, specifically including the following steps:

[0021] S1. First, perform environmental perception and parameter calculation;

[0022] S2. Then, make mechanical dynamic adjustments to the movable power amplifier track module;

[0023] S3. Perform closed-loop control of the acoustic system based on the adjusted phased array sound source configuration;

[0024] S4. Design a fault tolerance mechanism.

[0025] In a preferred embodiment, the specific process of environmental perception and parameter calculation in step S1 is as follows:

[0026] S1.1 First, environmental data is collected: the sound velocity, salinity, turbidity and water temperature of the water area are obtained through a multi-parameter water quality sensor, then the AUV attitude data is obtained through the inertial navigation module, and then the background spectrum of environmental noise is collected through the hydrophone module.

[0027] S1.2, Perform sound velocity compensation calculation: The sound velocity compensation calculation yields the correction coefficient. The specific steps are as follows:

[0028] Using the Leroy correction formula:

[0029] c = 1449.2 + 4.6T - 0.055T 2+1.34(S-35)+0.016D+0.07(NTU);

[0030] The calculation process is as follows: when the temperature T = 15℃, the salinity S = 34.5‰, the depth D = 200m, and the turbidity NTU = 8, the calculated c = 1481.6m / s;

[0031] Compared to the default value c0 = 1500 m / s, a correction factor is generated:

[0032] k c =c / c0 = 0.9877;

[0033] S1.3 Finally, formulate the array optimization decision for the transducer array: formulate an array adjustment scheme for the transducer array based on environmental perception data, system hardware limitations, and acoustic performance.

[0034] In a preferred embodiment, during step S2, the position of the phased array sound source on the movable power amplifier track module is controlled by the track servo controller receiving adjustment instructions, and then controlling the start and stop of the track motor driver and the elevation motor driver to adjust the position of the phased array sound source unit installed on the track.

[0035] In a preferred embodiment, the specific steps of acoustic closed-loop control in step S3 are as follows:

[0036] S3.1, Delay parameter generation;

[0037] S3.2 Dynamic verification.

[0038] In a preferred implementation, in step S4, the fault tolerance mechanism design includes formulating corresponding countermeasures based on the fault type:

[0039] 1) When the multi-parameter water quality sensor fails, enable historical data interpolation;

[0040] 2) When the track of the portable power amplifier track module is stuck, switch to electronic beamforming mode;

[0041] 3) When the network is interrupted, data is cached locally for ten minutes and then transmitted after the network is restored.

[0042] In a preferred embodiment, the specific process for generating the delay parameter in step 3.1 is as follows:

[0043] S3.1.1 Data Input: Set the spatial coordinates of the transducers in the transducer array. The origin of the coordinate system is the geometric center of the transducer array. The X-axis of the coordinate system is along the longitudinal direction of the hull, and the Y-axis is along the transverse direction of the hull. The transducer coordinates are set as (xi, yi), where i = (1, 2, 3, ..., 16). Set the angle between the transducer orientation and the normal direction of the transducer array as θ. Set the distance between the transducer array and the phased array sound source target as R. Set the sound speed as c, and obtain the actual transducer spacing after the transducer position adjustment.

[0044] S3.1.2 Calculate the relative path difference: For the i-th transducer, its path difference relative to the array center is: Δd i =x i *cosθ+y i *sinθ;

[0045] S3.1.3 Calculate the theoretical time delay parameter: Convert the path difference of the transducer relative to the center of the array into a time difference: τ i =Δd i / c;

[0046] S3.1.4 Delay Quantization and Alignment:

[0047] The time delay quantization formula is: τ quantized =round(τ i / 1ns)*1ns;

[0048] The calculation steps for inter-channel synchronization alignment are as follows:

[0049] First, find the maximum time delay τ. max =max(τ1,τ2,...,τ) N The maximum value of N is 16;

[0050] Therefore, the relative time delay of each channel is: Δτ i =τ max -τ i ;

[0051] S3.1.5. Generate a delay table: The table includes the channel number and delay parameter values.

[0052] In a preferred embodiment, the specific steps of dynamic verification in step 3.2 are as follows:

[0053] S3.2.1 Preparation stage: First, set the parameters of the super-resolution imaging signal generator, then calibrate the power amplifier unit to the rated power, then connect the digital oscilloscope to the hydrophone probe and set the trigger mode to the upper edge trigger. At the same time, collect the background noise of the static water area and test the initial sound velocity c0.

[0054] S3.2.2, Transmission Triggering and Data Acquisition: The command and control terminal sends a single pulse signal to the super-resolution imaging signal generator. Then, each channel of the phased array sound source transmits signals according to the preset time delay table. Then, the direct wave signal returned by the transponder is acquired synchronously through the four-channel acquisition unit. The target reflected wave signal is obtained through the hydrophone module, and the sound pressure time domain waveform of the hydrophone module is obtained through the oscilloscope.

[0055] S3.2.3, Time Delay Synchronization Verification: Measure the trigger time difference of each channel using an oscilloscope, and determine the time delay error value between channels based on the aquatic environment;

[0056] S3.2.4 Beamfocusing effect verification: First, calculate the main lobe amplitude, and then calculate the amplitude ratio of the first side lobe to the main lobe. The verification formula is: Side lobe suppression ratio = 20log 10 (A side / A main ), where Amain is the peak amplitude of the main lobe and Aside is the peak amplitude of the largest side lobe;

[0057] S3.2.5 Signal Integrity Verification: Check that there is no distortion within the bandwidth of the transmitted signal and that the harmonic distortion is ≤-40dBc, then the spectrum is intact; perform autocorrelation analysis on the Costas encoded signal, and if the main lobe-to-side lobe ratio is ≥13dB, then the encoding is verified.

[0058] S3.2.6 Dynamic Environment Adaptability Verification: By rapidly injecting salinity change data, sound speed correction is triggered; by injecting high-turbidity water into the experimental chamber, the transmission power compensation under the changing turbid water scene is compared and verified.

[0059] Compared with the prior art, the advantages and positive effects of the present invention are as follows:

[0060] This invention addresses the problems of poor environmental adaptability, severe beam defocusing, and weak fault recovery capability of traditional fixed array underwater acoustic imaging systems in complex waters by using an environmental adaptive algorithm and a mechanical-electronic coordinated control mechanism. Furthermore, this invention improves the main lobe energy concentration through the coordinated optimization of real-time sound velocity compensation using the Leroy model, mechanical adjustment of the X / Y axis, and electronic time delay control. At the same time, it enhances system availability through hardware redundancy and algorithm degradation design, significantly improving imaging resolution and robustness in extreme scenarios such as turbid waters and abrupt changes in salinity. Attached Figure Description

[0061] Figure 1 This invention presents a schematic diagram of the hardware architecture of a shipborne information processing and display control system for underwater acoustic imaging.

[0062] Figure 2 This invention provides a schematic diagram of a module for an underwater acoustic imaging shipborne information processing and display control system.

[0063] Figure 3 This invention presents a schematic diagram of the arrangement of a movable power amplifier track module and transducer array for a shipborne information processing and display control system for underwater acoustic imaging. Detailed Implementation

[0064] 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.

[0065] Example 1

[0066] like Figure 1-3 As shown, the present invention provides a technical solution: a shipborne information processing and display control system for underwater acoustic imaging, comprising:

[0067] The core control unit includes a command and control terminal and a phased array control host computer;

[0068] An acoustic emission unit, comprising a frequency division imaging signal generator, a movable power amplifier track module, and a phased array sound source;

[0069] The data acquisition unit includes a four-channel acquisition unit and a hydrophone module;

[0070] An environmental perception auxiliary unit, which includes a multi-parameter water quality sensor and an acoustic detection and acquisition unit;

[0071] The positioning unit includes a GPS module and an inertial navigation module;

[0072] Data storage server, which receives data from environmental perception auxiliary unit;

[0073] The movable power amplifier track module includes a moving track, a track servo controller, a track motor driver, and an elevation motor driver. The moving track is used to mount the transducer array on the hull. The track servo controller is signal-connected to the track motor driver and the elevation motor driver. The movable power amplifier track module mounts the transducer array via the moving track, and the track servo controller drives the X / Y axis motors to dynamically adjust the horizontal spacing and vertical pitch angle of the transducers, thereby adapting to the influence of different water depths and water quality conditions on acoustic propagation and optimizing the array physical layout to enhance beam focusing performance. The phased array sound source includes a power amplifier unit and a transducer array. The transducer array includes sixteen transducers. The transducers receive electrical signals from the power amplifier unit. The phased array sound source is driven by the power amplifier unit to amplify the electrical signals and drive the sixteen transducers. Directional sound waves are generated through electro-acoustic conversion. The mechanical adjustability of the transducer array and the electronic time delay control work together to achieve adaptive adjustment of the sound wave radiation direction and energy, ultimately improving the resolution and environmental adaptability of underwater imaging.

[0074] Furthermore, the command and control terminal is connected to a super-resolution imaging signal generator via a 10 Gigabit Ethernet network. The super-resolution imaging signal generator connects to two power amplifier units via sixteen channels. Each power amplifier unit is allocated eight channels and connects to eight transducers. Each transducer is connected to one channel. The command and control terminal, as the core hub of the system, sends high-precision acoustic parameters to the super-resolution imaging signal generator via the 10 Gigabit Ethernet network and controls it to drive the two power amplifier units in two groups of the 16-channel signal, achieving precise matching between electrical signal power amplification and transducer operation. The command and control terminal is connected to a phased array control host computer via a 10 Gigabit Ethernet network. The phased array control host computer is connected to the hydrophone and the four-channel acquisition unit via two gigabit Ethernet networks respectively, and to the phased array control host computer via another 10 Gigabit Ethernet network. The phased array control host computer then acquires the hydrophone acoustic data and the time difference information of the four-channel acquisition in real time via the gigabit Ethernet network, completing beamforming and feedback calibration. The command and control terminal is connected to a track servo controller via a shielded twisted-pair cable. The track servo controller connects to a CA... The N-axis longitudinal line connects to the track motor driver and the elevation motor driver respectively. The track servo control uses a combination of shielded twisted-pair cable and CAN bus to achieve micron-level positioning of the X / Y axis motors. The command and control terminal connects to a digital oscilloscope via a USB 3.0 channel. The probe of the digital oscilloscope is connected to a hydrophone, and the USB 3.0 connection to the digital oscilloscope allows for real-time monitoring of the hydrophone's sound pressure waveform to verify signal integrity. The command and control terminal connects to a data storage server via optical fiber. The data storage server connects to the acoustic detection acquisition unit and multi-parameter water quality sensor data via a SAS interface. The optical fiber connection to the data storage server centrally manages the acoustic detection and water quality sensor data. The command and control terminal connects to a GPS module via RS232 and an inertial navigation module via a 10 Gigabit Ethernet. The RS232 interface with the GPS module obtains absolute positioning, and the 10 Gigabit Ethernet synchronizes the inertial navigation attitude data. Finally, a closed-loop control system for multimodal data fusion is constructed to ensure the spatiotemporal consistency of acoustic imaging and environmental adaptability.

[0075] Furthermore, the command and control terminal is equipped with an environment adaptive algorithm for multi-source data fusion processing, global task scheduling, and human-computer interaction interface rendering. The phased array control host computer receives hydrophone data in real time, calculates sound source channel delay parameters, and controls the signal generator and power amplifier unit. The super-resolution imaging signal generator generates frequency-modulated / phase-modulated transmission signals and receives delay parameters from the phased array control host computer, outputting them in separate channels. The command and control terminal integrates multi-source data through the environment adaptive algorithm to achieve global optimization decision-making, driving the phased array control host computer to analyze hydrophone reflected signals in real time and calculate sound source channel delay parameters. It synchronously controls the super-resolution imaging signal generator to generate frequency-modulated / phase-modulated encoded signals, which are then used by the power amplifier unit to drive the transducer array to transmit directional sound waves in separate channels. The movable power amplifier track module adjusts the element spacing of the phased array sound source according to water quality changes and adapts to different water depths by adjusting the array elevation angle of the phased array sound source. The transducer array converts electrical signals into sound waves and can be moved along the movable power amplifier track. Upon receiving mechanical adjustment commands, the module alters the spatial layout of the transducer array. The movable power amplifier track module dynamically adjusts the transducer spacing and pitch angle based on water quality parameters. Combining the transponder time difference data synchronously captured by the four-channel acquisition unit with the raw acoustic information provided by the hydrophone, a sound field propagation model is constructed. The four-channel acquisition unit is used to synchronously acquire transponder signals and transmit time difference data to the core control unit in real time. The hydrophone module is used to receive reflected sound wave signals and provide raw acoustic data for imaging. The multi-parameter water quality sensor is used to provide real-time feedback of aquatic environmental data and trigger adaptive algorithm parameter updates. The acoustic detection acquisition unit is used to monitor the direct wave of the phased array sound source and provide beam pointing calibration data. The multi-parameter water quality sensor triggers real-time algorithm parameter updates, and the acoustic detection acquisition unit monitors and calibrates the beam pointing through the direct wave, forming a closed loop of "environmental perception - mechanical adjustment - electronic control - data feedback," ultimately achieving high-resolution adaptive acoustic imaging and target localization in complex waters.

[0076] In this embodiment, the present invention is based on phased array acoustic technology. By coordinating acoustic transmission, data acquisition and environmental perception modules through a command and control terminal, the present invention achieves high-resolution detection and imaging of underwater targets. The present invention generates frequency-tunable / phase-tunable acoustic signals by a super-resolution imaging signal generator, which drives 16 transducers to form a dynamically controllable beam through a power amplifier unit. After the hydrophone array receives the reflected signal, it combines the data from multi-parameter water quality sensors and positioning units, and calculates the channel delay parameters in real time through an environmental adaptive algorithm, dynamically adjusting the array element spacing and pitch angle to optimize the focusing effect.

[0077] The command and control terminal of the present invention integrates acoustic, navigation and environmental data, schedules a signal processing cluster to complete motion compensation, super-resolution imaging and target recognition, and displays three-dimensional acoustic images and trajectory information in real time through a display and control interface.

[0078] This invention can achieve ultra-high imaging resolution in complex waters, such as brackish water areas. By using a movable track system to adapt to changes in sound speed and combining it with a real-time feedback mechanism, the delay of beam tracking is significantly compressed, effectively suppressing sound attenuation errors caused by sudden changes in water quality, and significantly improving the accuracy of underwater target detection and the system's environmental adaptability.

[0079] Example 2

[0080] like Figure 1-3 As shown, based on the underwater acoustic imaging shipborne information processing and display control system proposed in Embodiment 1, the environmental adaptive adjustment algorithm is used to optimize the array configuration of the phased array acoustic source according to the detected water quality data, specifically including the following steps:

[0081] S1. First, environmental perception and parameter calculation are performed. The specific process of environmental perception and parameter calculation is as follows:

[0082] S1.1 First, environmental data is collected: the sound velocity, salinity, turbidity and water temperature of the water area are obtained through a multi-parameter water quality sensor, then the AUV attitude data is obtained through the inertial navigation module, and then the background spectrum of environmental noise is collected through the hydrophone module.

[0083] Environmental data acquisition utilizes multi-parameter water quality sensors to obtain real-time data on sound velocity, salinity, turbidity, and water temperature. Combined with AUV attitude data from the inertial navigation module and environmental noise spectrum collected by the hydrophone module, a dynamic model of sound field propagation characteristics is constructed: sound velocity parameters are directly used for sound source delay calculation; salinity and turbidity data are correlated with sound wave attenuation coefficients; and water temperature changes affect transducer efficiency. Inertial navigation attitude data compensates for beam pointing deviations caused by hull motion, while environmental noise spectrum is filtered using an adaptive filtering algorithm to suppress background interference. Ultimately, this provides environmental baseline parameters for acoustic imaging and triggers mechanical adjustments to the transducer array and updates to electronic beamforming parameters, forming a closed-loop feedback loop from environmental perception to acoustic control. This significantly improves the imaging signal-to-noise ratio and target resolution in complex water environments.

[0084] S1.2, Perform sound velocity compensation calculation: The sound velocity compensation calculation yields the correction coefficient. The specific steps are as follows:

[0085] Using the Leroy correction formula:

[0086] c = 1449.2 + 4.6T - 0.055T 2 +1.34(S-35)+0.016D+0.07(NTU);

[0087] The calculation process is as follows: when the temperature T = 15℃, the salinity S = 34.5‰, the depth D = 200m, and the turbidity NTU = 8, the calculated c = 1481.6m / s;

[0088] Compared to the default value c0 = 1500 m / s, a correction factor is generated:

[0089] kc = c / c0 = 0.9877;

[0090] The sound velocity compensation calculation is based on the Leroy correction formula. It dynamically calculates the actual sound velocity value by comprehensively considering four types of environmental parameters: temperature (T), salinity (S), depth (D), and turbidity (NTU). The actual sound velocity value is then compared with the system's default sound velocity c0 = 1500 m / s to generate a correction coefficient kc = 0.9877. Its core principle is to correct the time delay parameters and beam focusing model by quantifying the influence of environmental factors on the sound wave propagation speed. Its function is to eliminate the sound velocity deviation caused by water temperature stratification, salinity changes, and suspended particles, ensuring the physical authenticity of the transducer channel time delay calculation, thereby improving the geometric accuracy of acoustic imaging and the accuracy of target positioning. At the same time, it provides key acoustic environmental parameter inputs for subsequent adaptive algorithms.

[0091] S1.3 Finally, formulate the array optimization decision for the transducer array: formulate an array adjustment scheme for the transducer array based on environmental perception data, system hardware limitations, and acoustic performance;

[0092] The array optimization decision of the transducer array is based on environmental perception data, system hardware constraints, and acoustic performance indicators. Through multi-objective optimization algorithms, such as genetic algorithms or convex optimization, a physical array adjustment scheme is generated: the element spacing is dynamically adjusted according to the measured sound velocity, the array pitch angle is adjusted according to the water depth changes to optimize the sound wave coverage, and the element excitation weights are designed in combination with the maximum output power limit of the power amplifier unit, so as to achieve optimal beam focusing and energy efficiency within the mechanically adjustable range. Its role is to overcome the environmental adaptability bottleneck of fixed arrays. Through the "mechanical deformation + electronic shaping" collaborative strategy, it solves problems such as sudden changes in sound velocity gradient and multipath interference in complex waters. Ultimately, the system achieves a dynamic balance between detection distance, resolution, and power consumption, significantly improving the robustness and scene generalization ability of underwater imaging.

[0093] S2. Then, the movable power amplifier track module is mechanically and dynamically adjusted. During the control process, the position of the phased array sound source on the movable power amplifier track module is adjusted by the track servo controller receiving the adjustment command and then controlling the start and stop of the track motor driver and the elevation motor driver to adjust the position of the phased array sound source unit installed on the track.

[0094] The mechanical dynamic adjustment of the movable power amplifier track module receives environmental adaptive algorithm instructions from the track servo controller, driving the track motor driver and elevation motor driver to adjust the spatial position of the phased array sound source unit in real time: the track motor driver adjusts the array element spacing to match the half-wavelength requirement under sound speed variation, avoiding beam grating interference; the elevation motor driver adjusts the array pitch angle to adapt to the sound wave coverage tilt angle at different water depths, combined with the time delay compensation of electronic beamforming, to form spatial-temporal joint focusing; its function is to break through the beam control limit of fixed arrays through physical array reconstruction, solve the sound field distortion problem caused by salinity jump or suspended matter, and reduce the sidelobe energy loss of electronic scanning, ultimately achieving the improvement of main lobe energy concentration and multi-target resolution capability of acoustic imaging under complex hydrological conditions, and can automatically trigger fault protection through preset safety thresholds to ensure the reliability of mechanical adjustment and system continuity;

[0095] S3. Based on the adjusted phased array acoustic source configuration, perform closed-loop control of the acoustic system. The specific steps of the acoustic closed-loop control are as follows:

[0096] S3.1 Delay parameter generation. The specific process for generating delay parameters is as follows:

[0097] S3.1.1 Data Input: Set the spatial coordinates of the transducers in the transducer array. The origin of the coordinate system is the geometric center of the transducer array. The X-axis of the coordinate system is along the longitudinal direction of the hull, and the Y-axis is along the transverse direction of the hull. The transducer coordinates are set as (xi, yi), where i = (1, 2, 3, ..., 16). Set the angle between the transducer orientation and the normal direction of the transducer array as θ. Set the distance between the transducer array and the phased array sound source target as R. Set the sound speed as c, and obtain the actual transducer spacing after the transducer position adjustment.

[0098] S3.1.2 Calculate the relative path difference: For the i-th transducer, its path difference relative to the array center is: Δd i =x i *cosθ+y i *sinθ;

[0099] S3.1.3 Calculate the theoretical time delay parameter: Convert the path difference of the transducer relative to the center of the array into a time difference: τ i =Δd i / c;

[0100] The spatial coordinates of the transducer array are set using a Cartesian coordinate system with the geometric center as the origin, and the position of each transducer is defined as (x, y, z). i ,y i Combining the orientation angle θ, target distance R, and corrected sound velocity c, the path difference and time delay parameters are calculated using a geometric acoustic model: Path difference Δd i =x i·cosθ+y i sinθ, time delay τ i =Δd i / c enables beamforming; its function is to parameterize the physical array onto a mathematical model, quantify the impact of the actual spacing after mechanical adjustment on beamforming, and dynamically correct θ and R using an environment adaptive algorithm to ensure coherent superposition of sound waves in the target area; in the supplementary mechanism, real-time coordinate system calibration technology can correct coordinate offsets caused by mechanical deformation, while iterative optimization of R value under the sound velocity gradient field further improves beam focusing accuracy in complex sound fields, ultimately achieving precise control from physical layout to acoustic performance;

[0101] S3.1.4 Delay Quantization and Alignment:

[0102] The time delay quantization formula is: τ quantized =round(τ i / 1ns)*1ns;

[0103] The calculation steps for inter-channel synchronization alignment are as follows:

[0104] First, find the maximum time delay τ. max =max(τ1,τ2,...,τ) N The maximum value of N is 16;

[0105] Therefore, the relative time delay of each channel is: Δτ i =τ max -τ i ;

[0106] Delay quantization and alignment achieve time synchronization alignment of multi-channel signals by discretizing the theoretical delay τi with a precision of 1ns and calculating the relative delay Δτi = τmax - τi based on the maximum delay τmax: the quantization process adapts to the hardware clock resolution to avoid beam phase error caused by the accumulation of delay tails; synchronization alignment ensures that the sound waves coherently superimpose at the target point by unifying the delay difference of each channel relative to τmax, and suppresses sidelobe rise caused by time mismatch.

[0107] S3.1.5. Generate a delay table: The table includes the channel number and delay parameter values;

[0108] The purpose of generating the delay table is to provide executable timing control parameters for the signal generator. Its underlying mechanism drives the digital delay line hardware through binary delay codes, and combines temperature compensation algorithms and fault tolerance mechanisms to ultimately achieve nanosecond-level precision beam spatiotemporal consistency control, providing underlying timing guarantees for high-resolution acoustic imaging.

[0109] S3.2 Dynamic verification. The specific steps of dynamic verification are as follows:

[0110] S3.2.1 Preparation stage: First, set the parameters of the super-resolution imaging signal generator, then calibrate the power amplifier unit to the rated power, then connect the digital oscilloscope to the hydrophone probe and set the trigger mode to the upper edge trigger. At the same time, collect the background noise of the static water area and test the initial sound velocity c0.

[0111] In the preparation phase, the transmission parameters of the super-resolution imaging signal generator are set, the power amplifier unit is calibrated to its rated power, a digital oscilloscope is connected to the hydrophone probe and set to rising edge trigger mode, and the background noise spectrum of the static water area and the initial sound velocity c0 are simultaneously acquired. The principle is to establish the system's baseline state: the signal parameters define the time-frequency characteristics of acoustic imaging, the power amplifier calibration ensures the stability of the transmission energy, the background noise analysis provides a reference spectrum for subsequent adaptive filtering, and the initial sound velocity c0 serves as the baseline value for the environmental compensation algorithm. In the supplementary phase, the cross-correlation method is used to verify the clock synchronization deviation between the hydrophone and the signal generator, and the linearity of the power amplifier is tested by injecting white noise. Finally, a repeatable standardized test environment is provided for dynamic verification, ensuring the accuracy of acoustic performance evaluation and the effectiveness of system robustness verification.

[0112] S3.2.2, Transmission Triggering and Data Acquisition: The command and control terminal sends a single pulse signal to the super-resolution imaging signal generator. Then, each channel of the phased array sound source transmits signals according to the preset time delay table. Then, the direct wave signal returned by the transponder is acquired synchronously through the four-channel acquisition unit. The target reflected wave signal is obtained through the hydrophone module, and the sound pressure time domain waveform of the hydrophone module is obtained through the oscilloscope.

[0113] The transmission trigger and data acquisition are achieved by sending a single-pulse trigger signal to the super-resolution imaging signal generator via the command and control terminal. This drives each channel of the phased array sound source to transmit coded signals according to a preset time delay table. Simultaneously, the four-channel acquisition unit synchronously captures the direct wave signal from the transponder, the hydrophone module receives the target reflected wave signal, and the digital oscilloscope records the sound pressure time-domain waveform and performs cross-correlation analysis with the theoretical waveform. The principle lies in achieving spatiotemporal alignment of the transmit-receive link through strict timing control. Its functions include: verifying time delay synchronization, extracting target echo time delay and Doppler frequency shift, and quantifying signal propagation distortion. A reference clock distribution network can be introduced to ensure sub-microsecond synchronization between the acquisition unit and the signal generator. Combined with pulse compression technology, the ability to extract weak reflected signals is enhanced, providing high-confidence spatiotemporal joint feature data for subsequent imaging algorithms.

[0114] S3.2.3, Time Delay Synchronization Verification: Measure the trigger time difference of each channel using an oscilloscope, and determine the time delay error value between channels based on the aquatic environment;

[0115] The time delay synchronization verification measures the trigger time difference of each channel using a high-precision digital oscilloscope, compares the preset time delay table with the actual transmission timing deviation, and dynamically sets the maximum permissible error threshold between channels based on environmental characteristics such as water sound velocity gradient and multipath effect. The principle is to quantify the inconsistency of hardware link delay through time-domain waveform cross-correlation analysis and eye diagram observation. Its functions include: ensuring the phase coherence of beamforming and suppressing imaging artifacts caused by time delay mismatch. An adaptive error compensation mechanism can be introduced, which automatically triggers time delay table recalculation and power amplifier unit power equalization when an excessive error is detected. At the same time, it combines the PTP protocol to reduce the impact of system reference clock drift, ultimately ensuring the robustness of beam spatiotemporal control and the repeatability accuracy of the imaging system under complex sound field conditions.

[0116] S3.2.4 Beamfocusing effect verification: First, calculate the main lobe amplitude, and then calculate the amplitude ratio of the first side lobe to the main lobe. The verification formula is: Side lobe suppression ratio = 20log 10 (A side / A main ), where Amain is the peak amplitude of the main lobe and Aside is the peak amplitude of the largest side lobe;

[0117] Beamfocusing performance verification is achieved by calculating the ratio of the peak amplitude of the main lobe to the peak amplitude of the maximum side lobe, and quantifying the beam energy concentration using the side lobe suppression ratio formula. The principle behind this is to evaluate the effectiveness of time delay control and array adjustment through acoustic field radiation mode analysis. Its functions include: verifying the sharpness of the main lobe under mechanical-electronic coordinated control; suppressing false alarms caused by side lobe interference; reconstructing the three-dimensional acoustic field distribution using near-field acoustic holography; identifying abnormal side lobes caused by array edge diffraction effects; introducing a dynamic weighting algorithm to optimize the element excitation weights; and eliminating external interference through environmental noise background comparison. Ultimately, this ensures that the system can still achieve high-fidelity beamfocusing in complex acoustic fields, providing core acoustic performance assurance for underwater target imaging.

[0118] S3.2.5 Signal Integrity Verification: Check that there is no distortion within the bandwidth of the transmitted signal and that the harmonic distortion is ≤-40dBc, then the spectrum is intact; perform autocorrelation analysis on the Costas encoded signal, and if the main lobe-to-side lobe ratio is ≥13dB, then the encoding is verified.

[0119] Signal integrity verification ensures the fidelity of acoustic signals throughout the transmission-propagation-reception link by analyzing the frequency domain and time domain autocorrelation characteristics of the transmitted signal. Spectrum verification uses FFT analysis to detect harmonic spurious signals caused by power amplifier nonlinearity, while time domain verification assesses the coding's resistance to multipath interference through autocorrelation peak sharpness. Its role is to avoid imaging blurring and false sidelobe interference caused by signal distortion, while ensuring pulse compression gain to achieve weak target detection. A pre-distortion correction algorithm can be introduced to compensate for power amplifier nonlinearity, combined with dynamic bandwidth allocation to avoid frequency band congestion, and an underwater channel equalizer can be used to suppress multipath delay interference. Finally, a full-link quality control system from signal generation to channel adaptation is constructed, laying the physical layer foundation for high-confidence acoustic imaging.

[0120] S3.2.6 Dynamic Environment Adaptability Verification: Trigger sound speed correction by rapidly injecting salinity change data; Verify transmission power compensation under changing turbid water scenarios by injecting high-turbidity water into the experimental chamber.

[0121] The dynamic environmental adaptability verification triggers real-time sound velocity correction by rapidly injecting salinity abrupt change data, and high-turbidity water is injected into the experimental chamber to simulate turbid water, comparing and verifying the system's ability to compensate for sound wave attenuation. The principle is to test the system's response speed to sudden changes in environmental parameters and the effectiveness of the adaptive strategy through extreme environment simulation. Its functions include: verifying the beam pointing stability under sudden changes in sound velocity gradient, ensuring that the target echo signal-to-noise ratio is maintained at ≥20dB in turbid water; introducing a multiphysics coupling model to predict the optimal compensation parameters in complex environments, combining a power-bandwidth joint control algorithm to reduce multipath interference, and achieving dynamic balance through a closed-loop feedback mechanism, ultimately ensuring that the system can still maintain >85% effective imaging coverage and ≤5% positioning error rate under extreme hydrological conditions such as salinity jumps and suspended sediment.

[0122] S4. Design a fault tolerance mechanism and formulate corresponding countermeasures based on the fault type:

[0123] 1) When a multi-parameter water quality sensor fails, historical data interpolation is enabled to prevent the environmental adaptive algorithm from being interrupted. Specifically:

[0124] 1.1) An ARIMA time series prediction model is used, combined with the real-time trends of water temperature and depth data, to dynamically compensate for missing salinity / turbidity data. For example, when a sensor fails, the current parameter value is predicted using Kalman filtering based on the correlation between sound velocity, salinity, and turbidity over the past 30 minutes, with the prediction error controlled within ±3%.

[0125] 1.2) The historical data window length is set to 30 minutes. After the time window is exceeded, it will automatically switch to conservative mode, and the interpolation effectiveness will be cross-validated by inverting the sound field characteristics through hydrophone.

[0126] 1.3) Introduce phase rotation compensation, add virtual array element position offset Δx'=Δx*(1+kc) when generating the time delay table, where kc is the track displacement obstruction ratio factor. According to the actual movable state of the array element, dynamically adjust the power weight of the power amplifier unit to avoid local overheating and optimize energy efficiency.

[0127] 1.4) The track jamming state is determined by combining the sudden change in motor drive current with the feedback from the position encoder;

[0128] 2) When the track of the portable power amplifier track module is stuck, switch to electronic beamforming mode. Compensate for the physical array by dynamically expanding the time delay parameter range, sacrificing ≤3dB of sidelobe suppression to maintain basic detection capability. Specifically:

[0129] 2.1) Read the drive current, position encoder feedback and temperature sensor data of the track motor driver and elevation motor driver in real time. If the motor current continues to exceed the limit and the position encoder data does not change, trigger a fault alarm.

[0130] 2.2) Expanding the original time delay quantization range, the frozen physical displacement is compensated by adding a virtual time delay. Assuming that the actual displacement of the i-th transducer is blocked due to track jamming, the proportion of actual displacement obstruction is ki∈[0,1], then the corrected time delay is:

[0131] τ i ′=τ i +k i *Δτ max ;

[0132] Where, Δτ max To maximize the allowable compensation delay, additional phase shifts are applied to the transducers of the frozen array to compensate for the lack of physical displacement:

[0133] φ i =2πf*τ i ′;

[0134] Where f is the center frequency of the transmitted signal;

[0135] 2.3) Dynamically adjust the output power of the power amplifier unit according to the actual movable state of the array elements:

[0136] P i =P max *(1-0.2k i );

[0137] By using the Class D amplifier closed-loop feedback of the power amplifier unit, the output impedance matching is monitored in real time to prevent hardware damage caused by power imbalance.

[0138] 2.4) The original beamforming uses an adaptive sidelobe suppression algorithm, such as Minimum Variance Distortionless Response (MVDR). After switching, it is downgraded to a delayed summation algorithm, sacrificing some sidelobe suppression capability in exchange for reduced computational complexity and ensuring real-time performance.

[0139] 3) When the network is interrupted, ten minutes of data is cached locally and transmitted after the network is restored. The local cache uses dual RAID1 solid-state drives for storage and embeds a Beidou short message module to realize emergency backhaul of critical data.

[0140] The fault tolerance mechanism ensures system continuity through a pre-set multi-level redundancy strategy. Its principle lies in building a multi-level fault tolerance system through hardware redundancy, algorithm degradation, and heterogeneous communication design. Its functions include: ensuring minimum functional availability of the system under extreme failures, reducing the risk of data loss, introducing fault tree analysis to achieve a self-diagnosis-self-repair closed loop, and combining FPGA hard real-time control to quickly switch redundant links, ultimately achieving high reliability shipboard operation requirements.

[0141] In this embodiment, water quality, inertial navigation, and acoustic data are fused in real time using an environmental adaptive algorithm to dynamically optimize the phased array sound source configuration. The sound velocity is corrected based on the Leroy formula, and time delay parameters are generated. A high-precision servo motor is driven to adjust the transducer spacing and pitch angle. Combined with electronic beamforming, spatiotemporal joint focusing is achieved. Synchronous acquisition and dynamic verification are triggered by a single-pulse coded signal, and the robustness of the system is ensured through extreme environment simulation. A three-level fault-tolerant mechanism is adopted to ensure continuous operation under fault conditions. Ultimately, in complex waters, the main lobe energy concentration is improved and the imaging resolution is increased, achieving high-precision adaptive underwater target detection and imaging.

[0142] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments for application in other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. An underwater acoustic imaging shipboard information processing and display control system, characterized in that, The application relates to a high-precision underwater acoustic imaging system. The application comprises a core control unit, an acoustic emission unit, a data acquisition unit, an environment perception auxiliary unit and a positioning unit. The core control unit comprises a pointing terminal and a phased array control host computer. The acoustic emission unit comprises a frequency division imaging signal generator, a movable power amplifier track module and a phased array sound source. The data acquisition unit comprises a four-channel acquisition unit and a hydrophone module. The environment perception auxiliary unit comprises a multi-parameter water quality sensor and a sound detection acquisition unit. The positioning unit comprises a GPS module and an inertial navigation module. The movable power amplifier track module comprises a moving track, a track servo controller, a track motor driver and an elevation motor driver. The moving track is used to install a transducer array on a ship body. The track servo controller is connected with the track motor driver and the elevation motor driver. The phased array sound source comprises a power amplifier unit and a transducer array. The transducer array comprises sixteen transducers. Each transducer receives an electric signal of the power amplifier unit. The pointing terminal is connected with the super-resolution imaging signal generator through a gigabit network. The super-resolution imaging signal generator is connected with two power amplifier units through sixteen channels. Each power amplifier unit is connected with eight transducers through eight channels. The pointing terminal is connected with the phased array control host computer through a gigabit network. The phased array control host computer is connected with the hydrophone and the four-channel acquisition unit through two gigabit networks. The pointing terminal is connected with the track servo controller through shielded twisted pair lines. The track servo controller is connected with the track motor driver and the elevation motor driver through a CAN bus. The pointing terminal is connected with a digital oscilloscope through a USB3.0 channel. The probe of the digital oscilloscope is connected with the hydrophone. The pointing terminal is connected with a data storage server through an optical fiber. The data storage server is connected with the sound detection acquisition unit and the multi-parameter water quality sensor through a SAS interface. The pointing terminal is connected with the GPS module through an RS232. The pointing terminal is connected with the inertial navigation module through a gigabit network.

2. The water acoustic imaging shipboard information processing and display control system according to claim 1, characterized in that: The accuse terminal carries an environment adaptive algorithm, which is used for multi-source data fusion processing, global task scheduling and human-computer interaction interface rendering; The phased array control host computer receives hydrophone data in real time, calculates sound source channel time delay parameters and controls signal generator and power amplifier unit; The super-resolution imaging signal generator is used to generate adjustable frequency / phasing transmission signal and receive phased array control host computer time delay parameters and divide channel output; The movable power amplifier track module is used to adjust the element spacing of the phased array sound source according to the change of water quality and adjust the array pitch angle of the phased array sound source according to different water depth; The transducer array is used to convert electrical signals into sound waves, and can change the spatial layout of the transducer array under the condition that the movable power amplifier track module receives mechanical adjustment instructions; The four-channel acquisition unit is used to synchronously acquire transponder signal and real-time transmission time difference data to the core control unit; The hydrophone module is used to receive reflected sound wave signal and provide original acoustic data for imaging; The multi-parameter water quality sensor is used to feed back water environment data in real time and trigger adaptive algorithm parameter update; The sound detection acquisition unit is used to monitor the direct wave of the phased array sound source and provide beam pointing calibration data.

3. The water acoustic imaging shipboard information processing and display control system according to claim 1, characterized in that: The environment adaptive adjustment algorithm is used to optimize the array pattern of the phased array sound source according to the detected water quality data, which specifically includes the following steps: S1, first, environmental perception and parameter calculation; S2, then, mechanical dynamic adjustment of the movable power amplifier track module; S3, according to the adjusted phased array sound source array pattern, acoustic system closed loop control is carried out; S4, design fault tolerance mechanism.

4. The water acoustic imaging shipboard information processing and display control system according to claim 3, characterized in that: In step S1, the specific process of environmental perception and parameter calculation is as follows: S1.1, first, environmental data acquisition: obtain the sound velocity, salinity, turbidity and water temperature of the water area through the multi-parameter water quality sensor, then obtain the AUV attitude data through the inertial navigation module, and then collect the environmental noise background spectrum through the hydrophone module; S1.2, then, sound velocity compensation calculation: sound velocity compensation calculation obtains the correction coefficient, the specific steps are as follows: Leroy correction formula is adopted: c = 1449.2 + 4.6T - 0.055T 2 + 1.34(S-35) + 0.016D + 0.07(NTU); The calculation process is: when the temperature T=15℃, the salinity S=34.5‰, the depth D=200m, and the turbidity NTU=8, the calculation result c=1481.6m / s is obtained; Compare with the default value c0=1500m / s to generate the correction coefficient: k c = c / c0= 0.9877; S1.3, finally, the array optimization decision of the transducer array is made: according to the environmental perception data, system hardware limitations and acoustic performance, the array adjustment scheme of the transducer array is made.

5. The water acoustic imaging shipboard information processing and display control system according to claim 3, characterized in that: In step S2, the position of the phased array sound source on the movable power amplifier track module is adjusted in the control process. The track servo controller receives the adjustment instruction, then controls the start and stop of the track motor driver and the elevation motor driver, and adjusts the position of the phased array sound source unit installed on the track.

6. The water acoustic imaging shipboard information processing and display control system according to claim 3, characterized in that: In step S3, the specific steps of acoustic closed loop control are as follows: S3.1, time delay parameter generation; S3.2, dynamic verification.

7. The water acoustic imaging shipboard information processing and display control system according to claim 3, characterized in that: In step S4, in the design of fault tolerance mechanism, corresponding measures are taken according to the fault type: 1) When the multi-parameter water quality sensor fails, use the historical data interpolation; 2) When the track of the movable power amplifier track module is stuck, switch to the electronic beam shaping mode; 3) When the network is interrupted, locally cache ten minutes of data, and then transmit subsequently after recovery.

8. The water acoustic imaging shipboard information processing and display control system according to claim 6, characterized in that: In the step 3.1, the specific process of the time delay parameter generation is as follows: S3.1.1, data input: set the spatial coordinates of the transducers in the transducer array, the origin of the coordinate system is the geometric center of the transducer array, the X-axis of the coordinate system is along the ship body longitudinal direction, the Y-axis of the coordinate system is along the ship body transverse direction, the transducer coordinates are set as (xi, yi), wherein i=(1, 2, 3,..., 16), the angle of the transducer relative to the normal direction of the transducer array is set as θ, the distance between the transducer array and the target of the phased array sound source is set as R, the sound speed is set as c, and the actual transducer spacing after transducer position adjustment is obtained; S3.1.2, Calculate relative wave path difference: For the ith transducer, its wave path difference relative to the array center is: i = x i *cos θ + y i *sin θ; S3.1.3, Compute theoretical latency parameter: convert wave path difference of transducer relative to array center to time difference: τ i = Δd i / c; S3.1.4, time delay quantization and alignment: The time delay quantization formula is: τ quantized = round(τ i / 1ns)*1ns; The calculation steps of the inter-channel synchronization alignment are as follows: First find the maximum delay τ max = max(τ1, τ2,..., τ N N has a maximum value of 16; So the relative time delay of each channel is: Δτ i = τ max - τ i ; S3.1.5, generate the time delay table: the table content includes the channel number and the time delay parameter value.

9. The water acoustic imaging shipboard information processing and display control system of claim 6, wherein: In the step 3.2, the specific steps of dynamic verification are as follows: S3.2.1, preparation stage: first, set the parameters of the super-resolution imaging signal generator, then calibrate the power amplifier unit to the rated power, then connect the digital oscilloscope to the hydrophone probe, set the trigger mode to the upper edge trigger, simultaneously collect the static water background noise, and test the initial sound speed c0; S3.2.2, transmission trigger and data acquisition: the control terminal sends a single pulse signal to the super-resolution imaging signal generator, then each channel of the phased array sound source transmits signals according to the preset time delay table, then the direct wave signals returned by the transponder are collected synchronously through the four-channel acquisition unit, the target reflected wave signals are obtained through the hydrophone module, and the sound pressure time domain waveform of the hydrophone module is obtained through the oscilloscope; S3.2.3, time delay synchronization verification: measure the trigger time difference of each channel through the oscilloscope, and determine the time delay error value between channels according to the water environment; S3.2.4, beam focusing effect verification: first calculate the main lobe amplitude, and calculate the ratio of the first side lobe to the main lobe amplitude, the verification formula is: side lobe suppression ratio = 20log 10 (A side / A main ), wherein A main is the peak amplitude of the main lobe, and A side is the peak amplitude of the maximum side lobe; S3.2.5, signal integrity verification: check that there is no distortion in the transmission signal bandwidth, and the harmonic distortion is ≤-40dBc, then the spectrum is complete; perform autocorrelation analysis on the Costas coded signal, and the main lobe to side lobe ratio is ≥13dB, then the coding verification is completed; S3.2.6, dynamic environment adaptability verification: trigger the sound speed correction by rapidly injecting salinity change data; compare and verify the transmission power compensation under the scene change of turbid water body by injecting high turbidity water body in the experimental cabin.

Images