MARC record from Internet Archive

LEADER: 02136nam 2200289 a 45 0
001 a187333
008 970708s1990 caua b f000|0 eng d
040 $aCMontNP$cCMontNP
086 0 $aD 208.14/2:NPS-55-90-21
100 1 $aRead, Robert R.
245 12 $aA study of underwater sound ray tracing methodology /$cRobert R. Read.
260 $aMonterey, Calif. :$bNaval Postgraduate School ;$aSpringfield, Va. :$bAvailable from National Technical Information Service,$c[1990]
300 $ai, 97 p. :$bill. ;$c28 cm.
500 $aCover title.
500 $a"NPS-55-90-21."
500 $a"September 1990."
500 $aAD A229 666.
504 $aIncludes bibliographical references (p. 93).
520 $aAn operational study has been made of algorithms employed in short base line underwater position location systems. Some important sources of systematic error have been uncovered. The issues studied include isospeed vs. isogradient ray tracing, effect of the depth velocity profile and water layer thickness, approximate vs. exact array tilt corrections, and ray tracing initialization methodology. It is shown that the practice of constant speed extrapolation of depth-velocity information can cause considerable mischief. The best remedy is to measure speed all the way to the bottom. It is further shown that the systematic errors are periodic functions of the azimuth direction of the sound ray from the receiver array. The amplitudes of these functions are greater for the more severely tilted arrays. An alternative algorithm is proposed that reduces these errors by at least an order of magnitude. Keywords: Ray tracing; Calibration; Underwater tracking; Short baseline systems; Systematic errors. (JHD)
592 $aaq/aq cc:9116 07/08/97
650 4 $aACOUSTIC TRACKING.
650 4 $aRAY TRACING.
650 4 $aUNDERWATER TRACKING.
710 2 $aNaval Postgraduate School (U.S.).$bDept. of Operations Research.
740 01 $aNPS-55-90-21.
926 $aNPS-LIB$bDIGIPROJ$cD 208.14/2:NPS-55-90-21$dBOOK$eNEVER$f1
926 $aNPS-LIB$bFEDDOCS$cD 208.14/2:NPS-55-90-21$dBOOK$f2