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Appendix A: Standard Data Available in the Alvin Data System

Raw Data - Time Information
DatumUnitsAccuracyResolution
Time in HHMMSS formatlocal10-8                        sec/day1 sec
Date in YYDDMM formatlocal--1 day
Time in seconds since 1/1/1970
00:00:00 GMT  (valid through year 2037)    
sec (GMT)    10-8/day1 sec
Time zone adjustment
(GMT=Local+TZA)        
sec    --1 sec
Alvin dive number------

Raw Data - Scientific Data
DatumUnitsAccuracyResolution
Precision depthmeters1 m0.1 m
Backup depthmeters5 m0.1 m
Non-precision(strain gauge) depthmeters22 m0.1 m
Altitude, 0-50 m rangemeters1 m0.1 m
Hdg relative to true northdegrees1.5 deg0.1 deg
Low water temperature, 0-20C
(one or more probes)
deg C0.5 deg0.001 deg
High water temperature, 30-800C
(none to several probes)
deg C5 deg0.1 deg
User frequency counters (10)0-65535 counts/second----
User event counters (3)0-65535 counts----
Pitch attitudedeg0.5 deg0.001 deg
Roll attitudedeg0.5 deg0.001 deg

Raw Data - Acoustic Navigation Data
DatumUnitsAccuracyResolution
Interrogation freq (Tx)KHz.005 KHz0.1 KHz
Tracking freq (Tx)KHz.005 KHz0.1 KHz
LBL receive freqs (4)KHz.005 KHz0.1 KHz
LBL 2-way travel times (4) sec2 msec0.1 msec
Nav xcvr operating mode(various)----

Raw Data - Alvin Operating Data
DatumUnitsAccuracyResolution
Hydraulic system pressurepsi10 psi0.1 psi
Ballast air pressurepsi120 psi0.1 psi
Variable ballast tempdeg C0.5 deg0.1 deg
Variable ballast pressurepsi25 psi0.1 psi

Computed Data - Scientific Data
DatumUnitsAccuracyResolution
Median altitudemeters1 m0.1 m
Vertical ratem/min----

Computed Data - Acoustic Navigation Data
DatumUnitsAccuracyResolution
X position in netmeters1-10 m--
Y position in netmeters1-10 m--
Latitude/longitudedeg, min--0.0001 min
Target bearingdeg----
Target rangemeters----
Target Xmeters----
Target Ymeters----
Target #meters----
Horizontal ratem/min----

Computed Data - Alvin Operating Data
DatumUnitsAccuracyResolution
Variable ballast weightpounds20 lbs--
Variable ballast ratelbs/min----

Last updated: February 27, 2007