Q. How can I reduce the GPS Height to VORF?
A. Based on the NPD-S files, you should be able to reduce to VORF like this:
- Import NPD-S file
- Calculate GPS-Tide on one of the GPS-Tide singlebeam channels:

- Select the right VORF file

- Smooth the new GPS Tide relative to VORF

- Export it

- Reimport into NaviEdit with Ascii Importer and link it to the SBD file without height reference.
- You will probably need to set the Draft in the HeaderEditor
