Horizontal accuracy is 20m (no differential GPS correctors applied), vertical accuracy is depth dependent (~1% of water depth), WGS84 datum. These data are not to be used for navigation. Depths mapped range from 10 - 300 m. The AHI was deployed from the NOAA Ship Oscar E. Sette and surveyed independently during ship operations in other locations in American Samoa.
The multibeam bathymetric data in generic sensor format from AHI0402 were submitted to NOAA's National Geophysical Data Center (NGDC) in Boulder, CO, for distribution in 2005.
Equipment serial numbers and software versions are as follows:
RESON 8101-ER multibeam echosounder DOC inventory #: CD0000537418 Firmware, dry: 8101-2.07-2D4D Firmware, wet: 8101-1.06-2F6B
POS/MV Model 320, version 3 DOC inventory #: CD0000476647 PCS serial #: 474 IMU serial #: 203 Controller software: v 18.104.22.168
Seabird SBE19 CTD: Serial #: 3029
R/V AHI Lever Arm Distances and Alignment Offsets The R/V AHI Reference Point (RP) is defined to be the intersection of the vessel's centerline, the cabin deck and the bulkhead immediately aft of the transducer. This is marked by a punch in the deck weld at that location. Positive X means the point is forward of the RP, positive Y means the point is to starboard of the RP, positive Z means the point is below the RP. The loaded waterline is defined as the intersection of the vessel's performance wing with the hull at the transom.
Antenna Baseline Distance, m: 1.229 Transducer depth below waterline, m 0.62
RP to IMU 0.80 0.00 0.08 RP to Primary GPS Antenna -3.55 -0.61 -1.88 RP to Vessel 0.16 0.00 0.77 RP to Sensor 1(MB transducer) 0.16 0.00 0.77 RP to Sensor 2 0 0 0 RP to Aux. GPS Antenna 0 0 0 RP to Heave lever arm(deg) -0.67 0.00 0.00 IMU rotation Ref. Frame, deg 0 0 0 Sensor 1 rotation Ref. Frame, deg 0 0 0 Sensor 2 rotation Ref. Frame, deg 0 0 0
Roll offset: +0.5 deg Pitch offset: 0.0 deg Gyro offset: 0.0 deg
Resource Description: Reson 8101ER Multibeam Sonar Data from Cruise AHI0402 (R/V AHI)
These data are also archived through NOAA's National Geophysical Data Center at <http://www.ngdc.noaa.gov/mgg/bathymetry/multibeam.html>
Data Format - Generic Sensor Format, as described in <http://www.ldeo.columbia.edu/res/pi/MB-System/formatdoc/gsf_spec.pdf>