156 results about "Frequency noise" patented technology

A kind of atomic gyroscope pumping rate stable composite control method based on phase reshaping extended state observer and power approaching sliding mode control.Aiming at the problems that standard linear extended state observer has steady-state estimation error under the action of ramp disturbance, disturbance estimation phase lag and it is difficult to balance between observation bandwidth improvement and noise sensitivity, a composite corrector composed of lead network and lag network is cascaded at the output end of disturbance estimation of extended state observer, the disturbance estimation channel is shaped in frequency domain, phase lead is provided in mid-frequency band to reduce compensation delay, amplitude lag characteristic is used to suppress high-frequency noise, and parameter constraint design is used to realize zero-error estimation of ramp disturbance;At the same time, a power approaching sliding mode controller is constructed to improve the adaptability to the nonlinear, internal and external coupling and parameter uncertainty of atomic gyroscope system, and the phase reshaping extended state observer is combined to effectively estimate and feed forward compensate the lumped disturbance, so as to improve the stability and accuracy of pumping rate control.The present application can balance dynamic anti-disturbance performance, steady-state control accuracy, convergence speed and noise robustness without significantly improving the observation bandwidth, and is suitable for atomic gyroscope precision control system affected by ultra-low frequency slowly varying disturbance.

This invention discloses a method, apparatus, terminal device, and computer-readable storage medium for suppressing high-frequency noise. The method acquires a target audio signal, inputs it into a target noise model for classification, and obtains the noise type of the target audio signal. When the noise type is burst noise, multi-segment suppression processing is performed on the target audio signal based on a multi-segment noise suppression curve to obtain a reduced-noise frequency signal. The multi-segment noise suppression curve is obtained by segmenting a preset default noise suppression curve. This invention provides a high-frequency noise suppression scheme that segments and suppresses high-frequency burst noise, thereby ensuring voice call quality while effectively suppressing high-frequency burst noise.

The application discloses a motion electrocardio processing method and system, and relates to the technical field of electrocardio signal processing. The motion electrocardio processing method provided by the application comprises the following steps: acquiring electrocardio signals under different motion states; performing empirical mode decomposition on the motion electrocardio to decompose the electrocardio signals into a plurality of intrinsic mode functions, and performing high-pass filtering operation on the low-frequency intrinsic mode functions to suppress low-frequency noise in the motion electrocardio; then, performing variational mode decomposition on the remaining components to more accurately extract variational mode functions of different frequencies, and performing center frequency judgment on each variational mode function; for the mode functions smaller than the center frequency, non-local mean noise reduction is adopted; for the mode functions greater than or equal to the center frequency, singular value decomposition is adopted to reduce noise and realize baseline interference suppression; finally, the mode functions after noise reduction are reconstructed, the wavelet threshold method is adopted to reduce noise for the electromyographic interference noise in the motion electrocardio, so that a clean motion electrocardio signal waveform after noise interference suppression is obtained, and subsequent further analysis is facilitated.

The application discloses a Helicobacter pylori breath test signal denoising fitting method and system, and belongs to the technical field of medical detection and signal processing. The method processes the continuous monitoring signal of the 13CO2 / 12CO2 isotope ratio in exhalation: firstly, the original signal is subjected to band-pass digital filtering to suppress high-frequency noise; then, low-frequency drift is eliminated through adaptive baseline correction to generate a drift-removed signal; subsequently, a robust peak value recognition algorithm is used to extract physiological response characteristics; finally, the identified peak value is taken as the center, a nonlinear function with physiological constraints is used for local fitting, and the Delta Over Baseline value is calculated based on the generated fitting curve with high precision. The application effectively solves the signal distortion problem caused by breathing fluctuations, instrument noise and the like in in vivo detection, realizes high-fidelity restoration of the Helicobacter pylori metabolic response, and significantly improves the detection accuracy and reliability of the breath test.

This invention discloses a low-frequency noise reduction and sound insulation device for industrial applications, belonging to the field of noise control technology. The device includes an outer soundproof cover, an inner composite sound-absorbing structure, and an active noise control system. The outer soundproof cover is constructed of high-density board. The inner composite sound-absorbing structure is located on the inner wall of the outer soundproof cover and includes an acoustic metamaterial layer and a micro-perforated plate layer, which are spaced apart to form a first resonant cavity. The active noise control system includes: an error microphone embedded in the inner wall of the outer soundproof cover; a controller electrically connected to the error microphone; and a secondary sound source electrically connected to the controller and installed on the inner wall of the outer soundproof cover. This invention achieves broadband passive sound absorption through the composite structure of acoustic metamaterial and micro-perforated plate, providing a high signal-to-noise ratio environment for the active control system. Furthermore, the active control system based on the FxLMS algorithm precisely cancels residual low-frequency line spectra, achieving efficient and stable low-frequency noise reduction.

The present application relates to aerospace, geological exploration and micro-light detection fields, and particularly relates to a reconfigurable noise shaping successive approximation register analog-to-digital converter, which comprises a sampling unit, a capacitive digital-to-analog converter array, a comparison unit, a passive noise shaping feedback unit, a successive approximation control unit, an output unit and a mode control unit. The sampling unit samples and holds an input signal, and the capacitive digital-to-analog converter array outputs to the comparison unit. The comparison unit compares its output with a common-mode reference voltage, and the result is sent to the successive approximation control unit. In the noise shaping mode, the successive approximation control unit additionally generates an integral clock timing to activate the passive feedback unit, samples a residual voltage and feeds back to the digital-to-analog converter array. The output unit drives the conversion result to a lower circuit. The present application also contains a method. The present application can effectively suppress the capacitive parasitic effect and low-frequency noise, realize flexible switching between high-speed conventional mode and high-resolution noise shaping mode, and significantly improve the system performance.

An intake pipe integrating two silencing structures includes a pipe body formed by the joining of an upper shell and a lower shell. A first opening and a second opening are formed on the bottom wall of the lower shell. A first cylinder and a second cylinder are integrally formed on the outer bottom surface of the lower shell, corresponding to the positions of the first and second openings, respectively. The opening of the first cylinder overlaps with the first opening and forms a wavelength tube within the first cylinder. The opening of the second cylinder overlaps with the second opening, and a cover plate is provided over the second opening. A third opening is formed in the middle of the cover plate. An annular baffle is integrally formed on the bottom surface of the cover plate, corresponding to the position of the third opening. The cover plate, the annular baffle, the second cylinder, and the third opening form a holmhertz silencer. By integrating a wavelength tube and a holmhertz silencer on the intake pipe, a wider frequency band can be covered, forming a complementary effect, thereby reducing mid-to-high frequency noise and low-frequency noise within the intake pipe respectively. This invention has a simple structure and is easy to manufacture and assemble.

This invention discloses a multi-source electromagnetic noise suppression method based on noise classification and deep learning, belonging to the field of geophysical electromagnetic exploration technology. The method includes: segmenting and preprocessing the original electromagnetic observation sequence; using an improved U-Net network with an encoder embedded in a Mamba time-series modeling module for low-frequency noise suppression; identifying strong noise types in the data segments using a ROCKET classifier; based on the classification results, calling a second improved U-Net network trained for the corresponding noise type for class-based targeted denoising; and finally, splicing the data segments to obtain complete, high-quality data. This invention, through a phased processing framework of "low-frequency pre-suppression—noise classification—class-based denoising," combined with the strong time-series modeling capabilities of the Mamba module and the efficient classification performance of ROCKET, significantly improves the suppression accuracy and signal fidelity for complex, multi-source electromagnetic noise, and is particularly suitable for processing ground and airborne electromagnetic exploration data.

This invention discloses a thin-layer weak signal enhancement method based on cyclic spectrum enhancement technology. The method first preprocesses the original seismic data using a Gaussian smoothing operator to suppress random noise while preserving the main signal features. Then, even-order derivative operations are introduced to enhance the high-frequency components and detailed information of the seismic signal, highlighting the reflection characteristics of the thin-layer interface. To address the issue of high-order derivatives easily introducing high-frequency noise, a Butterworth low-pass filter is used for directional noise reduction. Finally, an adaptive cyclic termination condition is used to determine the optimal derivative order, and the derivative seismic traces are superimposed onto the original seismic traces to achieve thin-layer weak signal enhancement. Numerical simulations and tests with actual seismic data show that this method can effectively enhance the weak signals of 10m (λ / 4) and 5m (λ / 8) thin layers, improve the continuity and clarity of the phase axis of thin-layer reflected waves, and thus enhance the identification capability of thin-layer reservoirs under complex geological conditions.

This utility model relates to the field of sound insulation technology, and discloses a soundproof shell and air conditioning unit, including a shell, a rubber damping layer disposed on the inner side of the shell, and a low-frequency sound-absorbing layer and a high-frequency sound-absorbing layer. By placing the low-frequency sound-absorbing layer between the rubber damping layer and the high-frequency sound-absorbing layer, this utility model allows the rubber damping layer to buffer low-frequency vibrations during air conditioning unit operation, reducing the low-frequency vibration energy transmitted to the shell and lowering low-frequency noise generation. The low-frequency sound-absorbing layer, positioned adjacent to the rubber damping layer, can promptly receive and absorb the low-frequency vibration energy buffered by the rubber damping layer, resulting in more thorough low-frequency noise reduction and improving the overall noise reduction effect of the soundproof shell. This effectively prevents the shell from vibrating and amplifying low-frequency noise. Simultaneously, the high-frequency sound-absorbing layer absorbs and blocks high-frequency noise, ensuring that noise in different frequency bands (low, medium, and high) is effectively absorbed and blocked.

The utility model discloses a cooling tower spray water noise reduction device. High-temperature circulating water is uniformly sprayed to the surface of filler through a water distribution system to form a water film or water drops, the water film or water drops fall into a water pool at the bottom of the cooling tower after the water temperature is reduced and collide with accumulated water in the water pool to generate noise, and the noise belongs to high-frequency noise and disturbs residents. The device comprises a cooling tower, a spray water buffer rack is placed at the bottom of the cooling tower, the spray water buffer rack comprises an upper buffer plate, a lower buffer plate and a buoy, the upper buffer plate and the lower buffer plate are connected and fixed through a plurality of stand columns, two circles of supporting legs are fixed at the bottom of the lower buffer plate, and the two circles of supporting legs are fixed at the bottom of the lower buffer plate. The bottoms of the supporting legs are fixed on the buoy; a water collecting hole is formed in the middle of the lower buffer plate and is connected with a water conduit. The cooling tower spray water noise reduction device is used for cooling tower spray water noise reduction.

This invention discloses a rotation-consistent target perception high-frequency wildlife re-identification method, relating to the field of board processing technology. This invention performs rotational modeling only on the target high-frequency tokens or their corresponding two-dimensional feature maps obtained through target-frequency joint selection. This allows rotation robustness learning to focus on identity-related details such as texture, spots, stripes, and contours of the animal subject. This mechanism reduces the risk of rotational enhancement of background high-frequency noise. The target-frequency joint selection mechanism suppresses high-frequency noise from natural backgrounds such as grass, leaves, water ripples, and rocks, improving the model's ability to focus on the animal subject's discrimination region. The target-frequency joint selection mechanism identifies image patches that are truly relevant to the animal subject and have significant high-frequency details, and establishes feature-level rotation and consistency constraints only on the target high-frequency tokens, thereby simultaneously suppressing background high-frequency noise and enhancing robustness against directional changes.

The utility model relates to a kind of rock breaking rods, it includes: including main body and hammer head, main body is covered with flexible layer outside, main body is equipped with movable cavity inside, movable cavity is arranged close to the bottom end of main body, several movable members are filled in movable cavity, and movable member can freely move in movable cavity. Hammer head is located below main body, and is connected with the bottom end of main body. Inertial motion of movable member can absorb and offset part of kinetic energy that bounces back to rock breaking rod, so as to significantly reduce rock breaking rod echo, improve rock breaking effect. Movable member shakes in movable cavity can significantly reduce the vibration of rock breaking rod and the intensity of high-frequency noise radiated outward, so as to be conducive to ecological environmental protection. Flexible layer covered outside main body buffers the vibration of main body, and reduces the noise propagated outward by main body. Therefore, the rock breaking rod can reduce the adverse effects of energy bouncing back to rock breaking rod.

The utility model discloses a kind of steam heating is used to reduce noise mute device, it is related to steam heating noise reduction technical field, including the base and outer fairing of being installed together, and the base is formed with the fairing of being guided into the pressure reduction cavity between outer layer, outer fairing has the steam hole for the steam body of being guided into pressure reduction cavity into the exhaust steam channel, counterweight ball is placed in the steam outlet of base, and the fairing of being guided into the channel for reducing noise is equipped in pressure reduction cavity. The utility model passes through shunting steam flow, makes steam flow in the fairing of being guided into pressure reduction, reduces speed, reduces steam flow turbulent flow, effectively eliminates high-frequency noise, in turn reaches the effect of noise reduction, simultaneously, using counterweight ball can prevent low-pressure steam from entering heating cavity in advance to cause condensate accumulation to influence heating efficiency.

The present invention provides an active inductive impedance enhancement circuit applied to a power line path. It utilizes a closed-loop control technique to detect residual high-frequency signals on the power line and generates a compensation current injected into the secondary side of the main inductor accordingly. The invention actively suppresses high-frequency current flowing through the main inductor, thereby significantly enhancing its impedance against high-frequency noise.

This invention discloses a high-precision zero-crossing processing system and method for frequency and phase calculation, comprising: a voltage input front-end circuit module, a current input front-end circuit module, an analog-to-digital conversion module, a hardware zero-crossing judgment circuit module, and a main control microcontroller module. In this scheme, the filters and protection components in the voltage input front-end circuit module and the current input circuit effectively filter out high-frequency noise, ensuring the purity of the voltage and current signals. The analog-to-digital conversion module further filters out noise interference through a rate-of-change check mechanism, ensuring that the detected zero-crossing point is the true zero-crossing point of the voltage signal. Linear interpolation is used to more accurately determine the time position of the zero-crossing point, reducing interpolation errors and significantly improving the accuracy of frequency measurement. The main control microcontroller module accumulates sufficient samples and combines them with a weak low-pass filter to smooth the changes during the cycle, further stabilizing the frequency measurement results.

This invention discloses a grain depot equipment operation status monitoring and green energy-saving control system, belonging to the field of intelligent grain depot control technology. It collects the instantaneous output frequency and total harmonic distortion (THD) of the variable frequency drive equipment, and simultaneously separates high-frequency noise components higher than the grain temperature change frequency. Based on the output frequency, it determines whether it falls into a sensitive frequency band, and performs causal correlation analysis between the high-frequency noise energy spectrum and the THD to calculate a reliability index. When the reliability exceeds a threshold, it determines that the temperature sampling value is contaminated by harmonics, discards the value, and generates a repaired temperature value based on the heat diffusion law of the grain pile using time-domain prediction or spatial interpolation. The repaired value is used for energy-saving control drive; when a temperature jump and an energy-saving control action are detected to be inversely related, the start / stop command of the variable frequency drive equipment is forcibly blocked. This invention, by identifying and suppressing harmonic interference from the variable frequency drive, avoids reverse control caused by temperature data jumps, ensuring the safety and reliability of energy-saving operation of the grain depot.

The application belongs to the technical field of vibration sensors and relates to a graphene vibration sensor based on a rigid-flexible mixed vibration pickup structure and a sensing method thereof, and comprises a top electrode assembly, a bottom electrode and a signal processing circuit board, a limiting frame and graphene aerogel; the through hole of the limiting frame is sleeved on the cylindrical surface of the graphene aerogel; the top electrode assembly, the bottom electrode and the signal processing circuit board respectively clamp the graphene aerogel of the limiting frame from the upper and lower sides; the two ends of the flexible beam of the top electrode assembly are respectively connected with the inner ring of the rigid outer frame and the edge of the exposed copper sheet, the upper end surface of the graphene aerogel is conductively attached to the bottom surface of the exposed copper sheet, and the lower end surface of the graphene aerogel is conductively attached to the upper surface of the bottom electrode and the signal processing circuit board; the rigid-flexible combined beam amplifies the vibration displacement, the limiting frame guarantees the structural stability, and the signal conditioning circuit is highly integrated at the bottom layer, so that the direct current drift and high-frequency noise are eliminated from the source, and the signal-to-noise ratio of the sensor is greatly improved.

This invention discloses a method and system for calculating high-frequency noise of underwater vehicles based on fluid compressibility. The method includes: obtaining the local static pressure of the flow field; calculating the density distribution of the compressible water flow based on the local static pressure and the compressibility characteristics of the water; constructing a flow control equation considering fluid compressibility based on the density distribution of the compressible water flow, and solving the velocity distribution, pressure distribution, and density fluctuation distribution of the flow field through numerical iteration; constructing the FW-H equation based on the density distribution, velocity distribution, pressure distribution, and density fluctuation distribution of the compressible water flow; and embedding the flow control equation and the FW-H equation considering fluid compressibility into a computational fluid dynamics solver for solving, thereby obtaining the high-frequency noise calculation results of the underwater vehicle. This invention can effectively control the high-frequency noise rise phenomenon and improve the accuracy of high-frequency noise prediction for underwater vehicles.

This application discloses a method for extracting the DC component of an AC signal, comprising: acquiring the AC signal to be processed and its fundamental angular frequency; sequentially performing low-frequency harmonic elimination processing on the AC signal according to the fundamental angular frequency in descending order of harmonic order, wherein each low-frequency harmonic elimination process is configured to: eliminate the current target low-frequency harmonic, while amplifying the high-frequency noise and higher-order harmonics in the AC signal that have not been eliminated, causing the high-frequency noise and higher-order harmonics to trigger amplitude limiting; after completing a preset number of low-frequency harmonic elimination processes, filtering the obtained signal to extract the target DC component from the AC signal; wherein the amplitude limiting value is set to be significantly higher than the amplitude of the target DC component in the AC signal, so that the amplitude of the high-frequency noise and higher-order harmonics after amplitude limiting is far away from the amplitude of the target DC component. This method can achieve fast and accurate extraction of the target DC component.

The application discloses an audio loudness improvement and dynamic range optimization method and related device, and the method comprises the following steps: obtaining an audio signal to be optimized, performing frequency response correction and dynamic noise suppression filtering processing on the audio signal to be optimized based on a multi-stage IIR filter, and obtaining a filtered audio signal; designing an adaptive dynamic compressor based on an LUFS loudness evaluation model, performing dynamic compression processing on the filtered audio signal by using the adaptive dynamic compressor, and obtaining a compressed audio signal; performing filtering optimization processing on the compressed audio signal based on a multi-stage low-pass filter, and outputting a filtered and optimized audio signal. In the embodiment of the application, the loudness is improved, the dynamic details of the audio signal are retained, the high-frequency noise amplification and the excessive compression of the low-frequency signal are avoided, the automatic dynamic compression of the audio signal is realized, and the problems such as "breathing effect" and "peak leakage" are eliminated.

This utility model provides an aluminum profile structure for an assembly line with a silent guide rail, comprising: an aluminum profile body with rounded edges at the corners; a first mounting area and a second mounting area respectively located on the upper and lower parts of the aluminum profile body; protective baffles and a first sound-absorbing part on both sides of the top of the first mounting area to reduce noise generated by friction during contact. The aluminum profile structure for an assembly line with a silent guide rail provided by this utility model features rounded edges for enhanced safety; modular partitioning of the aluminum profile body into a first and second mounting area; and a silent guide rail assembly that works in conjunction with the first and second sound-absorbing parts to ensure smooth operation and prevent deviation. Simultaneously, multi-frequency noise reduction is achieved through elastic deformation and sound wave scattering, enhancing the sound absorption effect. Weight-reducing holes reduce weight while maintaining strength; and the first and second accessory mounting slots support external device expansion, forming a lightweight, low-noise, and highly adaptable silent assembly line system.

The present disclosure provides a blood flow imaging method, system and storage medium, which obtains a plurality of initial ultrasonic blood flow images and a plurality of target detection groups, filters each target detection group based on a filter set to obtain a corresponding preset number of data groups, obtains a blood flow average speed value corresponding to each target detection group based on the filtered data groups, and generates an ultrasonic blood flow image based on the blood flow average speed value. The present disclosure utilizes a filter set composed of multiple filters with different cutoff frequencies to process ultrasonic echo signals, screens out target data groups corresponding to blood flow regions to generate an ultrasonic blood flow image, effectively reduces high-frequency noise caused by hardware and low-frequency clutter caused by tissue motion, makes the calculated blood flow velocity more close to the true value, and can enhance the blood flow of a certain region in a targeted manner, so as to facilitate the judgment of the degree and starting position of regurgitation.

This invention discloses a high-frequency piezoelectric signal denoising method based on WPD-AT-EMD, belonging to the field of signal processing technology. The method involves wavelet packet decomposition of the original noisy signal to obtain sub-signals in multiple frequency bands. For each high-frequency sub-signal, a threshold is calculated according to a locally dynamically adjusted adaptive threshold rule, and an improved threshold function is used for threshold processing. Then, all processed sub-signals are reconstructed to obtain a preliminary purified signal. The preliminary purified signal is then subjected to EMD decomposition to obtain several Intrinsic Mode Function (IMF) components. This invention employs a collaborative denoising mechanism combining wavelet packet decomposition, adaptive threshold processing, and empirical mode decomposition, which can accurately suppress high-frequency noise in strongly interfering and non-stationary high-frequency piezoelectric signals while completely preserving signal impulse characteristics and key waveform information. It effectively improves the signal distortion and feature loss problems that easily occur in traditional denoising methods and significantly alleviates the EMD mode aliasing phenomenon.

This invention discloses an automatic testing method, system, device, and product for the current linewidth of a narrow-linewidth laser. The invention acquires frequency noise spectrum data of the laser at different injection currents using a current scanning method with a preset step size, and calculates the linewidth of the laser at different injection currents based on this data. Finally, based on the integrated linewidth at different injection currents and using an automatic inflection point identification algorithm, the evolution characteristics of the laser's frequency noise spectrum under different injection currents are analyzed, thereby determining the integrated linewidth of the laser at its optimal operating current. Therefore, this invention provides a new linewidth measurement technology. Compared to traditional delay heterodyne methods and improved zero-beat schemes, it eliminates the need for long / short laser delays, thus avoiding the environmental noise introduced by long fiber delays and the problem of weak signals being submerged by system noise due to short fiber delays, thereby improving measurement accuracy.

This invention discloses a multi-layer composite sound-absorbing device. The double-layer micro-perforated plate of this invention includes an upper micro-perforated plate and a lower micro-perforated plate, which are connected by a disc spring device. The upper and lower micro-perforated plates are connected around their perimeter by a frame, ensuring the disc spring device between them is compressed. The density gradient porous sound-absorbing material layer is composed of at least two layers of sound-absorbing material with different densities stacked together. This multi-layer composite sound-absorbing device is composed of resonant and resistive sound-absorbing materials, achieving excellent low-frequency broadband sound absorption, effectively solving low-frequency noise pollution problems in substations, converter stations, and other fields. By adjusting the plate spacing to change the compression state of the disc springs, different stiffness characteristics are obtained, thereby enhancing the resonant sound absorption effect for specific frequency bands of noise and specifically improving the sound absorption coefficient of the device for specific frequency bands of noise.

This utility model discloses a signal acquisition and amplification circuit, relating to the field of signal acquisition and transmission. The circuit includes: a Wheatstone bridge module for feeding back a fixed voltage signal and a temperature change signal to a differential amplifier module; and a differential amplifier module for varying the output voltage when there is a difference between the input fixed voltage signal and the temperature change signal. The advantages of this utility model are: by setting a differential amplifier module, the small signal obtained from the sensor is linearly amplified, which is more conducive to acquisition and identification by subsequent circuits; the circuit makes the correspondence between the output voltage signal Vout and the NTC resistor value clear and easy for subsequent circuits to acquire; the signal input impedance is high and the output impedance is low, which is beneficial for impedance matching with subsequent circuits and reduces power consumption; the differential amplifier module provides filtering for high-frequency noise; and the NTC resistor has low self-heating, ensuring the accuracy and stability of temperature acquisition.

The application discloses a water acoustic signal motion noise suppression method and device based on a vector magnetic sensor and belongs to the technical field of low-frequency ocean environment physical field monitoring. The method uses a vector magnetic sensor carried on a mooring platform to collect magnetic field signals in real time, obtains a relative angle change sequence representing platform attitude change by calculating the minimum rotation angle of magnetic field vectors at adjacent moments. The sequence is taken as a reference input, and acoustic signals collected synchronously by a hydrophone are input into a variable step adaptive filter; the filter dynamically adjusts the step according to the energy of the reference input, estimates and offsets low-frequency noise introduced by platform motion in the acoustic signals, and outputs the suppressed water acoustic signals. The application realizes real-time and adaptive suppression of platform motion noise through joint processing of magnetic fields and acoustic fields, solves the problem that a traditional method is difficult to distinguish low-frequency motion interference from effective acoustic signals, and significantly improves the water acoustic observation precision and data quality of the mooring platform under complex sea conditions.