Vert. Uncertainty

[Ben Purvis]

I've discovered that near buildings on some occasions fixed results do not provide accurate results(in topo mode). My solution thus far has been to do a much longer occupation time than normal and/or just collect a benchmark away from building and shoot the necessary information conventionally. I'm curious as to how other users are resolving this relatively minor (but important to know about) issue.

 

[Nate The Surveyor]

GPS is a statistical measurement tool. Larger samples (Time) are always more sound statistically. Nature of the beast.
N

 

[Tom Bushelman]

I don't topo near buildings with GNSS because of that. I did a 30 acre topo job in which I mounted the LS to a side by side and drove a pattern for three hours, driving over manholes that had been located conventionally in the process. The GNSS shots compared within a tenth of the conventional shots but near the buildings, it got a little squirrely but was fairly obvious. Buildings were to be demolished so I didn't have to get too close to them.

 

[avoidthelloyd]

If I only have a small number of shots, I will up my rod height and get up above the building. Then, when I pull out my level to check the FFEs, I will just do a manual check.