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GPS RTK Vertical Control

Posted: Thu May 17, 2012 8:48 am
by Quartaroli
Are there recommended standards and procedures to establish vertical control using GPS RTK other than Caltrans Manual?

Posted: Thu May 17, 2012 11:23 am
by Brad Luken
There are: NOAA Technical Memorandum NOS NGS-58 - Guidelines for Establishing GPS Derived Ellipsoid Heights (Standard: 2 cm and 5 cm) & NOAA Technical Memorandum NOS NGS-59 - Guidelines for Establishing GPS Derived Orthometric Heights

**Edit: These are not for RTK though

Posted: Thu May 17, 2012 4:29 pm
by Rob_LS
Check - NGS 58 & 59 are static GPS procedures.

"Are there recommended standards and procedures to establish vertical control using GPS RTK...?"

Don't use RTK to establish "vertical control" unless your requirements are very loose. I heard a great way to describe what you will likely get from RTK this week - "Can you live with your errors being about the size of a Red Bull can? Your position is most likely in there somewhere."

Posted: Thu May 17, 2012 4:38 pm
by Jim Frame
Ditto the remarks about RTK slop. You can usually do better than a Red Bull can with proper procedures, but outliers are always a problem.

For what it's worth, here's a link to the RTK vertical test we did for DWR:

http://members.dcn.org/jhframe/DWR/2011 ... mized).pdf

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