NAVIGATION FIELD DATA
The file nav.dat located in directory nav
contains the raw navigation that was collected
during the sidescan
component of the field program with the USGS differential GPS system.
The shorebased station for the GPS was the Coast Guard beacon at
Cape Henlopen, DE.
The navigation is an ASCII file with six fields separated by tabs.
Navigaton fixes are at 10 second intervals, and the file is separated
by a # -b into three parts each representing one night of sidescan
- Field 1: date and time (julian day:hour (GMT):minute:second)
- Field 2: Latitude (ie. 39d26.4093)
- Field 3: Longitude (ie. -74d17.5293)
- Field 4: Speed (computed from the navigation)
- Field 5: Heading (computed from the navigation)
- Field 6: Water Depth (derived from an Odem digital echo sounder).
Depths are in meters, but have not been corrected for the
depth of the transducer, which was about 2 m below the sea
surface, nor for the tide.
During the first night (146:22:29:05 through 147:09:59:20)
only the port channel of the sidescan was functional. During the
second night (147:22:32:22 through 148:09:04:20) and third night
(149:01:48:07 through 149:11:01:00) both channels of
the sidescan were working. Comments are preceeded with a ## in the
data records. Though the navigation for the first day of the survey
can be found on this disk, the collected sidescan is not considered
useful and, therefore, has not been archived here.
Return to R/V CAPE HENLOPEN 94-12 home page.