OF 03-150 Home
|Navigation for the cruise was acquired using the Wide Area
Augmentation System (WAAS), a GPS-based navigation and landing
system providing precision guidance to aircraft. The horizontal
and vertical accuracies of WAAS are comparable to those of Differntial
GPS. Due to the interior location of the study area, Coast Guard
Becons providing differential corrections to GPS readings, were
not accessible. Thus, WAAS was chosen as the navigation system.
Navigation files were created as follows: 'WAAS navigation'
was generated by pulling the navigation fix and the depth, as recorded
by the R/V Rafeal's hull-mounted echosounder, from the raw navigation
files as recorded by Coastal
Oceanographics, Inc. Hypack Max navigation acquistion package.
The 2 - 4 second fixes were 'stripped' out of the raw navigation
using various UNIX utilities. 'Sidescan-sonar navigation'
was generated by pulling navigation from the sidescan-sonar
headers. The navigation for individual
tracklines was then combined using UNIX utilities. 'Shot
navigation' was generated by stripping the navigation
for each shot from the SEG-Y header and reformatting the data
using various UNIX utilies. 'Shot navigation - 500 shot
interval' was generated by extracting navigation for
every 500 shots from the 'shot navigation' file. Navigation
for the first shot of each line was extracted from the 'Shot
navigation' file to generate the 'Start of line'
To view the trackline information see Figure
2, Figure 3, and Figure 5,
or view navigation data within the ArcView project
file stored on this CD-ROM. See GIS Data
for more information.
To view files in PDF format, download free copy of Adobe Acrobat Reader www.adobe.com/products/acrobat/alternate.html.