1、Designation:D631803(Reapproved 2014)Standard Practice forCalibrating a Fathometer Using a Bar Check Method1This standard is issued under the fixed designation D6318;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last rev
2、ision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This practice provides the user with procedures used inmanually calibrating the fathometer or electronic depthsounder.This narrativ
3、e describes calibration terminology,de-scribes acceptable environmental conditions for calibration,and describes the calibration procedures.1.2 The references cited contain useful information in theconstruction and the correct operation of the calibration equip-ment.1.3 Any references cited in this
4、narrative to specific prod-ucts or brand names are made for information only,and isintended to be descriptive,but not restrictive,of products thatwill perform satisfactorily.1.4 The values stated in inch-pound units are to be regardedas standard.The values given in parentheses are mathematicalconver
5、sions to SI units that are provided for information onlyand are not considered standard.1.5 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices an
6、d determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D1129 Terminology Relating to WaterD5073 Practice for Depth Measurement of Surface Water3.Terminology3.1 DefinitionsRefer to Terminology D1129 for termsused in this guide.3.2 Definitions o
7、f Terms Specific to This Standard:3.2.1 bara section of metallic channel,I-beam,T-beam,pipe,plate,or ball that will reflect sound waves produced by afathometer.3.2.2 bar-checka method for calibrating a fathometer bysetting a sound or accoustic reflector(bar)below a surveyvessel to a known depth belo
8、w a sounding transducer.3.2.3 draft(transducer draft)the vertical distance fromthe bottom of the transducer to the surface of the water.3.2.4 fathometerAn electronic device for registeringdepths of water by measuring the time required for thetransmission and reflection of sound waves between a sonic
9、transducer and the lake or river bottom.3.2.5 soundto determine the depth of water.3.2.6 sounding scrollthe chart record of an underwatercross section or profile of the bottom.3.2.7 transducera device for translating electrical energyto acoustical energy and acoustical energy back to electricalenerg
10、y.4.Significance and Use4.1 The accuracy of depth measurements made by a fath-ometer or echo sounder requires a number of correctionsbecause of the variability of sound or acoustic velocity in waterwith changes in temperature,salinity,and depth of water.Inaddition instability of the equipment can al
11、so result in signifi-cant errors.For additional information see Practice D5073.4.2 Calibration of echo sounding instruments is absolutelycritical in assuring the adequacy of depth measurements.Whenan echo sounder has been accurately calibrated,any observed(recorded)depth can be related to the true d
12、epth of water.Sincethe intended purpose of echo sounding is to measure the“true”depth,an independent“true”reference must be used.4.3 A bar-check is the most wide-spread,easiest toconstruct,and most economical mechanical method to deter-mine corrections for instrument and velocity errors.4.4 This pro
13、cedure explains the calibration of a fathometeror electronic depth sounder using a bar-check.4.5 Bar-checking techniques and equipment are general innature and may need to be modified for use in specific fieldconditions.1This practice is under the jurisdiction of ASTM Committee D19 on Water andis th
14、e direct responsibility of Subcommittee D19.07 on Sediments,Geomorphology,and Open-Channel Flow.Current edition approved Jan.1,2014.Published March 2014.Originallyapproved in 1998.Last previous edition approved in 2008 as D6318 03(2008).DOI:10.1520/D6318-03R14.2For referenced ASTM standards,visit th
15、e ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United Sta
16、tes1 5.Apparatus5.1 The device used for bar-checking must be a sound-reflecting surface that can be lowered to a known depth belowthe transducer of the survey vessel.See Fig.1.These sounding-refecting surfaces(or sounding targets)can be a bar made outof a section of metallic I-beam or T-beam,pipe,a rectangularsection of sheet metal,or a section of metal screen.5.2 Bars used in depths greater than 30 ft(10 m)should beat least 9 in.(23 cm)wide.The dimensions of the target dependon the type of surv