Four quantities to combine
Position
Latitude and longitude of the reference point, corrected when the mission requires it.
Heading
Vessel orientation used to project the transducer position.
Attitude
Roll and pitch describing instantaneous platform orientation.
Heave
Vertical motion superimposed on the measured depth.
Lever arms and alignment
The antennas, inertial unit and transducer do not occupy the same point. Their offsets in the vessel frame must be measured. A heading alignment or lever-arm error becomes a positioning error at the sounding point.
What RTK contributes
RTK reduces horizontal uncertainty and supports repeatable survey tracks. It does not correct poor installation geometry or time offsets between sensors.
A verifiable workflow
- Measure the position of every sensor in the vessel frame.
- Check heading alignment against a known reference.
- Configure data sources and rates.
- Run a reciprocal test line.
- Keep logs for post-mission analysis.