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I am subscribed to the State of Arizona's RTN network. I've inventoried the 55 mountpoints and found varying results. When the reception is good I get reliable information confirmed by existing record data. I've been told that it is not recommended for topo work, the vertical is subject to a shift or
phase which I am researching.
Could someone please explain this shift or share their experiences with RTNs?
Your help would be appreciated.
This Content Originally Published by a land surveyor to Land Surveyors United Network
During tests of our independent RTK measurement controller software for Android we've faced the same problem. Different RTN networks and height readings can differ about a few cm. There was a moments where height was OK, but sometimes there has been observed shift. Also the same thing was noticed by a surveyors which work on their software (like SurvCe) in other part of our country (Poland).
Thank you Mark, I've found different degrees of accuracy and would like to find a systematic approach for an adjustment. I believe there has to be a controlled fix... In any event I will keep you posted. Thanks Again, Paul
First I assume RTN is “Real Time Network” which is a network of CORS (Continuous Operating Reference Stations) consisting of both public & private partners. These 55 “mountpoints” all should have a data sheet that states how they were set so you can ascertain there precision & accuracy. RTN or VPN is only as good as its least common denominator which is cell service. I’ve had good results using Leica’s “SmartNet” checking into points I’ve ran static on in the past with mixed results on other monuments. The vertical component will all ways be the first to be denigrated so I don’t really get “the phase or shift” you’re stating … could you please elaborate.
I'm not sure I understand your situation. If you have 55 mount points, I doubt you are getting a network solution (implied by RTN). More likely you are getting corrections from one CORS within a network. If that is correct, getting different results is not very surprising. Every CORS occupies its own location with the unique environmental conditions of that place resulting in differences unique to that CORS.
Networking software by using the whole network simultaneously uses data from all the stations to determine and mitigate the idiosyncrasies. Mount points then are usually many fewer, identified by preferred formats rather than individual stations.
I'm still not sure I completely understood your request, but I hope this helps some.
Sorry to all...let me clarify....I have 55 mount points or continuous operating stations sending out corrections that I can choose from within the network. I connect to one mountpoint at a time, yes each mountpoint has a data sheet...I inventoried each mountpoint and found varying degrees of reception from my current location....I understand that the longer the base line isn't always an indication of poor reception, there are other factors...Thank you for explaining the differences J.Anthony, it does help.
My question is rooted in GPS legacy which is why I'm asking. At one time it was understood that collected data shifted globally along a vertical angle or plane...if I had a better handle on it I would be able to explain it better, I apologize....Thank You, Paul
After about 4-5 hours of data collection, the geometry of the baseline becomes irrelevant. If performing single base- baselines, after about the same time the length of the baseline becomes almost irrelevant (not counting the ppm of course).
Most single baseline processing will give ppm of about 1:1,000,000. Most network based processing will give ppm of about 1:10,000,000. This is primarily because the network can mitigate local errors of any of the individual stations.
If actually doing RTN (RTK) then measurements should be repeated about an hour or more later for redundancy and conformation of reasult.
"then measurements should be repeated about an hour or more later for redundancy and conformation of reasult."
I agree and have always practiced this...Thank you for taking the time to explain, I appreciate your insight.
You are correct in that this is not a network solutions (RTN) It is a collection of single base solutions.
Hello Tom, thanks...do you use the AZHMP? If so what have you found? Do you use AZGPS?
I've not used either service in Gila County as the areas we are working in typically have cell phone coverage challenges. Our typical critical point recovery seems to like being buried against the slope of a hill that shades cell reception.
I'm the AZGB CORS site owner/operator as well as the AZSV site host.
As a side note the bulk of the state run (ADOT is current curator moving from State Lands) AZHMP single station sites cross feed into the commercial AZGPS full RTN network.