Simrad Simrad SP70, Installation Manual

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Technical specifications
161
851-164336 / D
Speed log
The SP70 can interface to an external speed log via Ethernet, or a
serial line using the NMEA 0183 standard for reception of the
vessel speed. The sonar will
receive the following proprietary and
standard NMEA telegrams:
•
Water referenced and ground referenced speed data
•
Actual course and speed relative to the ground
Water referenced and ground referenced speed data
$??VBW,-mm.mm,-nn.nn,T,-mm.mm,-nn.nn,T<cr><lf>
where (from left towards right):
Component Content
?? Talker
VBW Identifier code for the type of system used
mm.mm longitude water speed (indication sign + or --)
nn.nn transverse water speed (don’t care)
T A or V = water_track status:
A=data valid, V=data invalid
mm.mm longitude ground speed (indication sign + or --)
nn.nn transverse ground speed (don’t care)
T A or V = bottom_track status:
A=data valid, V=data invalid
Actual course and speed relative to the ground
$??VTG,x.x,T,x.x,M,x.x,N,x.x,K<cr><lf>
where (from left towards right):
Component Content
?? Talker
VTG Identifier code for the type of system used
x.x,T Course, in degrees true
x.x,M Course, in degrees magnetic
x.x,N Speed, resolution 0.1 knots
x.x,K Speed, resolution 0.1 km/t