Survey-room shorthand for everything to do with position: the navigation file, the GNSS and inertial feed and the helm display. Crews talk about nav jumps when position leaps suddenly, nav spikes in the processed track, and swapping post-processed nav in for the real-time version. Bad nav is diagnosed by plotting the trackline and looking for zigzags, steps or gaps.
Nav jumped 6 metres at the end of line 12, check whether that's multipath off the ship's hull.
Also heard as
- navigation
- nav data
- nav jump
Related terms
GNSS
Global navigation satellite systems: satellite positioning such as GPS, GLONASS, Galileo and BeiDou, used together.
SBET
Smoothed best estimate of trajectory: the post-processed position and attitude file applied to multibeam data.
Float
Describes an RTK solution whose carrier-phase ambiguities are not yet fixed, giving only decimetre-level accuracy.
Fix
A measured position of the survey vessel at a recorded instant, and the act of determining it.