Global navigation satellite systems is the umbrella term for all satellite positioning constellations, which survey receivers track together for stronger geometry. On its own, a code solution gives metre-level positions, not enough for most hydrography. Survey work adds corrections from a base station, network or precise orbit service to reach decimetres or centimetres, and pairs the receiver with an inertial unit to ride through outages under bridges and cranes.
GNSS keeps dropping out under the container cranes, lean on the inertial for those lines.
Also heard as
- GPS
- satellite positioning
Related terms
RTK
Real-time kinematic: GNSS positioning that uses carrier-phase corrections from a base station to reach centimetres live.
PPK
Post-processed kinematic: GNSS positions computed after the survey from logged rover and base data, at centimetre level.
Float
Describes an RTK solution whose carrier-phase ambiguities are not yet fixed, giving only decimetre-level accuracy.
Nav
Shorthand for the vessel's positioning data stream, or for the positioning system as a whole.