Some standard content:
ICS17.140
National Standard of the People's Republic of China
GB/T 5265-2009
Replaces GB/T5265-1985
AcousticsMeasurement of underwater noise2009-09-30Promulgated
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of ChinaStandardization Administration of the People's Republic of China
Implementation on 2009-12-01
This standard replaces GB/T5265-1985 "Underwater noise measurement panel".
CB/T 5265—2009
Compared with GB/T5265-1985, this standard mainly adds the contents of uncertainty analysis and data processing. Appendix A, Appendix B, Appendix C and Appendix D of this standard are informative appendices. This standard is proposed by the Chinese Academy of Sciences. This standard is under the jurisdiction of the National Technical Committee for Acoustics Standardization (SAC/TC17). The drafting units of this standard are: Institute of Acoustics, Chinese Academy of Sciences, and System Institute of Naval Equipment Research Institute. The main drafters of this standard are: Ma Li, Liu Qingzi, Li Fan, Chen Yaoming. The previous versions of the standards replaced by this standard are: GR/T5265-1985.
1 Scope
Acoustics Underwater Noise Measurement
GB/T 5265-2009
This standard specifies the conditions and methods for measuring underwater noise so that the obtained measurement data can be compared and compared. This standard is applicable to underwater noise measurement in deep oceans, shallow continental shelves, ports and bays. Note: Underwater noise measurements in inland rivers, tidal moors, etc. can also refer to this standard. The applicable frequency range of this standard is: 20Hz~20kHz. The measurement results specified in this standard can provide data for the design of sonar systems, analysis and estimation of the range of aquatic equipment, background noise measurement of underwater radiation noise from ships, etc.: Underwater noise measurement, as a method of ocean acoustic sensing, can be used to estimate relevant environmental parameters, such as wind speed, waves, ground noise, sea level, etc.; monitor underwater biological noise and man-made noise sources; and can also be used to study the physical mechanism and statistical characteristics of underwater noise generation and transmission.
2 Normative references
The clauses in the following documents become clauses of this standard through reference in this standard. For dated references, all subsequent amendments (excluding errata) or revisions are not applicable to this standard. However, the parties who reach an agreement based on this standard are encouraged to study whether the latest versions of these documents can be used. For undated references, the latest versions are applicable to this standard. GB/T3223-1994 Acoustics - Field calibration method for underwater acoustic transducers GB/T3947-1996 Acoustics - Terminology GB/T 4128-1995 Acoustics - Hydrophone GB/T 4130-2000 Acoustics - Low frequency interface for hydrophone GB/T16165-1996 Hydrophone phase consistency measurement method GB/T18314 Global Positioning System (GPS) measurement specification 3 Terms and definitions The terms and definitions established in GB/T3947-1996 and the following terms and definitions apply to this standard. 3.1 Ocean noise - Noise caused in the ocean by natural causes, such as waves, currents, thermal disturbances, etc. Note: Noise other than biological noise, ground noise, rain noise, and man-made noise is called ocean noise, and the former is called marine environment transient sound (arnbient noise for the sca).
Hydrophone
An acoustic-electric transducer used to receive underwater acoustic signals. Note: There are different types of hydrophones due to different working principles, characteristics, and structures. For example, according to the working principle, there are piezoelectric hydrophones, electro-optical hydrophones, optical fiber hydrophones, micro-electromechanical hydrophones, etc.
Measuring hydrophones are used as secondary standard hydrophones for underwater acoustic measurement. The passband of the measuring hydrophone is calibrated by comparing with the standard hydrophone or the standard transmitter.
CB/T 5265—2009
[Underwater] Noise Band Sound Pressure Level [Underwater Inoise Band Sound Pressure Level The sound pressure level of underwater noise in a certain cheek band, in decibels (dB). The bandwidth and reference sound pressure should be specified. The noise band sound pressure level can be calculated using the formula (1):
L = 20 lg
Wu Zhong:
Lsa——noise band sound pressure level, in decibels (dB); p—measured noise sound pressure in a certain bandwidth, in Pascals (Pa); ,——reference sound pressure, in Pascals (Pa), usually P-1μPa, 3. 5
[Underwater] noise pressure spectrum [density] level (1)
The logarithm to the base 10 of the ratio of the pressure spectrum density of the underwater noise signal at a certain frequency to the reference sound pressure spectrum density multiplied by 20. The unit is dB. The noise sound pressure spectrum level can be calculated by formula (2): L = L-10 lgAf, where: L - the noise sound pressure spectrum (density) level, in decibels (dB), the reference value is 1 μPa/VHz L - the measured band sound pressure level with a center frequency of f, in decibels (dB), the reference value is 1 μPa△, f - the bandwidth relative to 1 H2. The noise (power) spectrum level of the instrument is equivalent to that of water. 3.6 Interference noise interference oise The interference caused by various reasons during measurement that affects the measurement. (2)
Note: Interference noise mainly comes from the electrical noise of the measuring hydrophone and instrument system, inductive impedance caused by poor grounding, self-noise of the system caused by water flow micro-excitation and various speed vibrations in the water, cable shaking and other hydrodynamic effects. 3.7
Hydrophone equivalent noise pressure spectrum level Hydrophone equivalent noise pressure spectrum level The logarithm of the ratio of the equivalent noise pressure spectrum of the hydrophone to its reference value multiplied by 20 with a base of 10. The unit is decibel (dB), and the reference value is 1 μPa//Hz.
Note: The equivalent noise of the hydrophone is the sound pressure when the plane sinusoidal traveling wave propagates parallel to the main axis of the hydrophone and the open circuit voltage generated by the hydrophone is equal to the Hz voltage in the bandwidth. The measurement method of the hydrophone equivalent noise pressure spectrum level is referred to GB/T4128-1995. 3.8
The lowest limit of Wenz noise Pressure spectrum level The Wenz spectrum diagram gives the lowest limit spectrum level of ocean noise measured. Note: The Wenz spectrum diagram is a summary of underwater noise measurement and has been widely used. 4 Measured quantitiesbzxz.net
The parameters of underwater noise measurement include:
a) Noise band sound pressure level Lri
b) Noise sound pressure spectrum (density) level L
In addition, according to needs, the instantaneous value of noise sound pressure can also be measured and stored to detect various types of noise such as pulse noise, non-stationary noise, etc. 2
5 Measuring equipment
5.1 Introduction
GB/T 5265—2009
The measuring equipment should be able to obtain the measured quantities specified in this standard. The original data samples should be saved for laboratory playback and further analysis. The basic measuring equipment should generally include the following parts: a) Sound transducer system
b) Measurement filter effect system;
c) Data recording and storage system:
d) Other systems: including blue system, processing system for special needs (such as correlation, statistics, etc.). 5.2 Acoustic transducer system
5.2.1 Structure and layout of acoustic transducer system The acoustic transducer system can be designed as a buoy or a submerged buoy according to the actual situation (it can also be a ship-borne system under certain circumstances). The structural and layout design requirements of the acoustic system are as follows: a) The acoustic system structure should not cause resonance in the underwater current, affect the sound uniformity, and form a sound barrier effect; b) Soft and thin cables should be used for signal transmission; c) Anti-vibration measures should be taken to fix the hydrophone, and a deflector should also be added. 5, 2.2 Measuring hydrophone
The measuring hydrophone should ensure high sensitivity and low noise to meet the measurement requirements. The specific technical requirements are as follows: a) In the measurement frequency range, the hydrophone sensitivity should be greater than -170dB, and the unevenness is less than ±2dB; b) Equivalent noise sound pressure spectrum level: less than the lower limit of the Wenz noise spectrum; d) Horizontal directivity, the deviation between its directivity diagram and the ideal directivity diagram should be less than ±1.5dB d) Vertical directivity: -3dB beam width should be greater than 60\e) Other electroacoustic performance should comply with the relevant provisions of GB/T4128-1995; f) If the measurement uses a hydrophone array, the phase inconsistency of each channel array element shall not exceed 2°. 5.3 Measuring filter amplification system
The measurement amplification system can use filters, amplifiers, etc. The specific requirements for filters and amplifiers are as follows: a) In the measurement frequency range: the frequency response fluctuation in the passband is 0.5dB; b) In the measurement frequency range: the minimum attenuation in the stopband is 60dB; c) In the measurement frequency range: the amplifier amplitude-frequency non-uniformity should be less than ±0.2dB. 5.4 Data recording and storage system
According to the requirements of noise measurement and recording, various types of digital acquisition and recording equipment can be used (if there are special needs, analog recording equipment, such as production level meter, etc., can also be used according to actual conditions). During the data recording process, according to different measurement requirements, it can be recorded in segments within the frequency band of 20Hz~20kHz; the data sampling rate should be more than twice the highest analysis frequency, and the data acquisition and recording accuracy should be guaranteed to be more than 12hit; the data recording length can be determined according to actual requirements, generally not less than 2min. 6 Measurement environment
6.1 Acoustic environment
The requirements for the acoustic measurement environment are as follows:
a) When using survey ships or other vessels to measure underwater noise at sea, whether using buoy or submerged buoy to deploy the acoustic transducer system, the effective distance between the measuring transducer system and the adjustment ship should be no less than 50m. When measuring in open sea areas and using fixed deployment, the distance between the acoustic transducer system and the shore should be no less than 1km. It should be avoided to deploy in seabed pits, on reefs or near them. If measuring in ports and bays and there are special requirements, the deployment of the acoustic transducer system should be determined according to needs.
GB/T 5265-—2009
b) If the measurement is carried out by shipboard, the main engine and auxiliary engine cannot be started during the noise measurement period, and human activities that can generate impact sound into the water are prohibited on board.
c) Select the actual on-site environment to be measured according to the purpose and requirements of the measurement, and the on-site environmental conditions must be described and recorded in detail. 6.2 Reduce interference noise
The requirements for reducing interference noise are as follows:
a) Try to avoid various interference noise sources that may exist near the measurement point; b) The electrical noise of the Xiepan hydrophone and measuring instrument used should be as low as possible, and its equivalent noise sound pressure spectrum level should be less than the Wen2 harmonic level limit.
7 Measurement steps
7.1 Equipment calibration
Calibrate all measurement equipment.
7.1,1 Measurement hydrophone calibration
Calibrate the measurement hydrophone (array) sensitivity, phase consistency, etc. The calibration standards are in accordance with GB/T 4128-1995, GB/T 4130-2000, GB/T3223-1994, GB/T16165-1996. 7. 1.2 Calibration of amplification and acquisition equipment
Use standard signal source to calibrate filters, amplifiers, collectors, etc. to ensure that the frequency and phase-frequency characteristics of the amplification equipment meet the measurement requirements.
7.1.3 Calibration of positioning system equipment
Calibrate GPS and other equipment. The calibration standards are in accordance with GB/T16165-1996 and GB/T18314 to ensure that the system positioning accuracy meets the measurement requirements.
7.2 System joint debugging
The entire measurement system should be joint debugged to check whether each part is working normally. 7.3 System calibration
Calibrate the system errors caused by the measurement equipment. 7.4 Matters to be noted in measurement
Matters to be noted in measurement are as follows:
a) Before measuring, first confirm that the measurement environment and various requirements are in compliance with the provisions of Chapter 6; b) Prevent the measurement system from being overloaded;
) During the measurement, the power supply facilities of the measurement equipment should not interfere with the measurement (for example, battery power supply); d) During the measurement, monitoring should be performed (on-site monitoring or recording and playback monitoring). 7.5 Underwater sudden sound measurement
7.5. 1 Underwater noise measurement method
Underwater noise measurement methods are divided into floating deployment, bottom-mounted deployment and ship-borne deployment under special circumstances. 7.5.2 General measurement steps
General steps for underwater noise measurement are as follows:
a) The measurement ship arrives at the site and deploys the acoustic transducer system (buoy, submerged buoy or ship-borne) at the specified position; receives and records underwater noise data according to the test requirements, monitors the noise signal synchronously, and stores the measurement data in the digital recording device. b) At the same time, the corresponding hydrophone sensitivity, amplifier gain, position of the hydrophone array and other measurement system related information are recorded; while observing the noise, several meteorological, oceanographic and acoustic environmental parameters required for the purpose of noise measurement should also be measured, such as the GPS position of the acoustic transducer, hydrological conditions, waves, wind speed, sound speed, etc. The measurement methods and measurement equipment should comply with relevant regulations!
d) Due to the night and seasonal changes of underwater noise, multiple measurements should be carried out at the same location. The number of measurements is determined according to needs, and the recording length of each measurement should not be less than 2tmin.
8 Data processing
8.1 Data processing method
GB/T 5265—2009
Intercept the effective receiving signal, correct the measured data according to the characteristics of the measurement system, and then perform spectrum analysis (such as FFT). Calculate the noise sound pressure level or vocal spectrum level of the required frequency band according to formula (1) and formula (2) in 3.4 and 3.5, and make corrections according to Appendix A. Other required quantities (such as statistical parameters, coherence function, spatial directivity of the noise field, etc.) can also be calculated and obtained using the data results. When considering the characteristics of the measurement system such as the amplification factor of the receiving system and the sensitivity of the hydrophone, the calculation formula is shown in Appendix B. Note: When calculating the noise sound pressure level and sound pressure spectrum level in this standard, the subroutine pwelchi of the power spectrum density estimation in the matlab screening program can be used. 8.2 Measurement uncertainty analysis
For the specific method of measurement uncertainty analysis, please refer to Appendix D. In the analysis process, the error of the sound field fluctuation measurement instrument and equipment is the main uncertainty factor.
9 Measurement Records
Description of the Measurement Site Environment
The recorded site environment includes:
a) Sea area location (latitude and longitude, place name), and meteorological situation at the measurement site; b) Description of the acoustic system deployment method and a schematic diagram of the structure; c) Measurement method (on the same ship, shore test station, offshore cell); d
Measurement method (wired telemetry, wireless telemetry, self-recording measurement; e) Through monitoring, record the form and subjective feelings of underwater noise in detail. The characteristics of the noise heard (such as the line spectrum close to pure tone, rhythmic harmonic components, etc.) should be recorded in detail and synchronously with the current environmental conditions as much as possible. Special attention should be paid to the description of abnormal noise conditions.
9.2 Records of measuring equipment
The recorded contents of the measuring equipment include:
a) Instruments used for measurement, including name, model, manufacturer and serial number;
c) Frequency response of the instrument system
d) Sensitivity, frequency response, horizontal and vertical directivity, equivalent noise pressure spectrum level, calibration date, accuracy level, etc. of the measuring hydrophone;
9.3 Records of acoustic data
The recorded contents of acoustic data include:
Sound pressure level L in noise frequency band;
Noise sound pressure spectrum level
|Interference noise correction value K;
d) Loudspeaker sound pressure spectrum level chart;
e) Give identification marks to the noise time value storage data, explain the measurement conditions and correction parameters and curves. 9.4 Environmental parameter data recording
The recorded environmental parameter data include: a) wind speed (m/s), sea condition (level);
b) current direction and velocity (kn);
c) water depth (m) sea water temperature surface;
d) sea waves (waveform.g)
A record of the appearance of ships and other underwater objects near the measuring station; According to the purpose of the acoustic measurement, select and record several of the above parameters, and refer to Appendix C for the report. The report content includes:
The date, time and location of the measurement:
The L, L of the measured noise, and the corresponding environmental conditions, parameters and relevant instructions during the measurement; A brief description of the measurement hydrophone and system structure and performance, and analysis and discussion of the measurement results.
Appendix A
(Informative Appendix)
Method for eliminating background interference noise
GB/T5265—2009
In order to reduce the influence of background interference noise on the measurement, the measured result shall be corrected by the following formula. The specific correction formula is shown in formula (A.1),
Lr L, K
Where:
—corrected sound pressure level of the subject belt, in decibels (dB), the reference value is 1μPa; Lar
Lar. Measured pre-belt sound pressure level, in decibels (dB), the reference value is 1μPa; K-corrected value, in decibels (dB).
Background interference noise and positive values are shown in A, 1. αL in the table is given by formula (A.2): AL — La — Lan
In the formula,
Lor, —-Equivalent sound pressure level of interference noise of the measurement system, in decibels (dB), and the reference value is 1μPa. Table A.1 Interference noise correction value table
Measurement disk invalid
-(A, 1)
.(A.2)
GB/T5265—2009
Appendix B
(Informative Appendix)
Calculation formula for underwater noise cheek belt sound pressure level
Band sound pressure level L. r
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