I have not done any studies on this. Only antidotal evidence. I am getting ready to extend some control for a roadway project done back about 15 years ago (only 3 original control points left). I plan on occupying each point 4 times. I plan on taking 3 minute observations each time and rotating the pole 90deg each shot to eliminate pole leveling errors. I will use RTPK observations on each one likely.
I will also likely do some testing with this extension as well. I will run static 2 hour sessions on each point and compare them to the averaged RTPK data.
I would have to respectfully disagree with John in that 5-20 second observations would not give me enough time to average heights that I would feel comfortable with. However, that is my personal opinion. Take it for what you will.
Hi Matt,
I have brought this up before but not sure I understand what is happening. You mentioned rotating the rover to eliminate leveling error. My license is in engineering so in CA, I can't do boundary work. I primarily do topos and various surveys to support my engineering projects. What I have found, with all of the topo work, is that there are areas of a parcel that will "fix" much faster if the LS is set to a specific bearing. It can make a difference by as much as 20 seconds or more. If we multiply 20 seconds by 100 and divide by 60 that can mean as much 16 extra minutes per 100 points just waiting for a fix. Is this just a function of the operation of the antenna? Is rotating the rover to achieve a faster fix considered something other than best practice. I suppose the most accurate solutions should converge on areas of the parcel where the rover had a bearing of N; however, I have not noted that accuracy follows a pattern related to bearing.
One more point. On nearly all of my projects I import an aerial image. It would be very easy to see a pattern emerge with point accuracy. What I typically see is high uniform precision. Shifting the aerial a few ft in the x and y direction and nearly all points align with the appropriate surface features on the aerial. I presume this is associated with the aerial and survey on different coordinate systems.
I am getting off into the woods here...one more comment/question. I believe that google uses WGS84. If I matched their coordinate system, would the differential disappear?
Thanks for any thoughts/comments anyone may wish to contribute. I know this post rambled a bit and swerved way off topic.