nav directory

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. 

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.

Navigaton fixes are at 10 second intervals, and the file is separated
by a # -b into three parts each representing one night of sidescan
surveying.  During the first night (146:22:29:05 through 147:09:59:20)
the 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 identified with a ## in the data record.