Henning, PLS, is a senior geodesist with NOAA’s National Geodetic Survey, where
he is helping to develop guidelines and support methodology for
real time positioning with state, national and international organizations. He
has more than 42 years of active experience in all phases of surveying
technology. He can be reached at firstname.lastname@example.org.
In previous issues, we have briefly visited three of the “seven C’s” of NOAA’s National Geodetic Survey (NGS), as best methods for real-time (RT) GNSS positioning. We can now move to the fourth “C”--constraints--to examine whether we should constrain coordinate solutions to the passive control marks in the ground or to active control points, such as those from a real-time network (RTN), or both.