File Format ID: spd

Format Description Creation Date: 2020-05-29

File Type: ASCII, whitespace-delimited and comma-separated values

Record Format: National Marine Electronics Association (NMEA) 0183 string with device id
and external, colon-separated datetime stamp.

Data Format Description:
The file contains PFEC, VDVLW and VDVHW  strings, alternating line-by-line.  Each NMEA 
record is prefixed by a datatype id, an external datetime stamp, and device tag.

Example Record:
NAV 2018/11/01 18:39:57.083 SPD $VDVLW,47702.775,N,46487.665,N*50

where:
     NAV                       Datatype ID
     2018/11/01 18:39:57.083   External datetime stamp (source unknown)
                                 2018         4-digit year
                                 11           2-digit month
                                 01           2-digit day of month
                                 18           2-digit hour [24-hour clock]
                                 39           2-digit minute
                                 57.083       decimal seconds
     SPD			           Device tag
     $VDVLW etc                NMEA record (see definitions below)

Definitions follow.

VHW Water Speed and Heading
1   2 3   4 5   6 7   8 9
|   | |   | |   | |   | |
$--VHW,x.x,T,x.x,M,x.x,N,x.x,K*hh

1) Degress True
2) T = True
3) Degrees Magnetic
4) M = Magnetic
5) Knots (speed of vessel relative to the water)
6) N = Knots
7) Kilometers (speed of vessel relative to the water)
8) K = Kilometres
9) Checksum

VLW	Distance Traveled through Water
1   2 3   4 5
|   | |   | |
$--VLW,x.x,N,x.x,N*hh
1) Total cumulative distance
2) N = Nautical Miles
3) Distance since Reset
4) N = Nautical 
9) Checksum

$PFEC - proprietary Furuno sentences
