Mike Berry, post: 322377, member: 123 wrote: I know one of those acquaintances & he's got me convinced. We've double tied hundreds and hundreds of monuments in the last 6 years with our Leica RTK units and I can't recall a one that was way-out wonky if the 3DCQ was dialed in. Sure, sometimes an additional observation is needed, but as far as the results of two strong observations, based on the 3DCQ, being out by crazy amounts like 2 feet or 2 tenths, we just don't see it. I attribute it to (1) good crews who know how to assess the factors like GDOP, SV constellation configuration, local obstructions, and the data on the controller {read "not button pushers, but smart, experienced, motivated surveyors"} (2) correctors from the Ore. Real Time Network and (3) our county Low Distortion Projection.
And if that paragraph doesn't dislodge Kent from his Fortress of Moping, nothing will.
I seem to recall that it took a while for Kent to migrate over to this site when it first opened. What I really miss was his Survey Noir with David K. O'Reilly and the Indian Casino survey ...
Norman Oklahoma, post: 322565, member: 9981 wrote: Five RTK ties on a brass monument. 3 are 15 second occupations. 2 are 90 seconds. Guess which ones. The monument is about 20 feet from a 2 story wood building. A three story brick and steel building is about 100 feet south. There are trees in the area partly obscuring the sky. In short, not an ideal RTK site.
(V149 RTK Normal 00000012 2015-06-16T12:17:40)
PDXA Delta-N -47738.5767 0.0065 0.0644 0.1 2:11
1020 Delta-E -13909.5413 0.0252 0.0566 0.4
Delta-U -82.2849 -0.0157 0.0854 0.2
Length 49723.7752(V148 RTK Normal 00000011 2015-06-16T12:16:17)
PDXA Delta-N -47738.5767 0.0018 0.0607 0.0 2:6
1020 Delta-E -13909.5413 0.0188 0.0551 0.3
Delta-U -82.2849 0.0261 0.0788 0.3
Length 49723.7752(V150 RTK Normal 00000014 2015-06-16T12:18:59)
PDXA Delta-N -47738.5767 0.0202 0.0579 0.3 2:16
1020 Delta-E -13909.5413 0.0393 0.0526 0.7
Delta-U -82.2849 -0.0215 0.0720 0.3
Length 49723.7752(V185 RTK Normal 00000047 2015-06-16T13:43:43)
PDXA Delta-N -47738.5767 0.0091 0.0565 0.2 2:191
1020 Delta-E -13909.5413 -0.0306 0.0511 0.6
Delta-U -82.2849 0.0259 0.0792 0.3
Length 49723.7752(V186 RTK Normal 00000048 2015-06-16T13:45:47)
PDXA Delta-N -47738.5767 -0.0253 0.0592 0.4 2:196
1020 Delta-E -13909.5413 -0.0430 0.0526 0.8
Delta-U -82.2849 -0.0084 0.0858 0.1
Length 49723.7752
Nothing apparent to me. The precision is impressive. Any idea how accurate?
Shawn Billings, post: 322636, member: 6521 wrote: Nothing apparent to me. The precision is impressive. Any idea how accurate?
My point is that there is little difference between the 15 second and 90 second occupations. That it seems that a 15 second is as good as a 90 second.
As far as accuracy, I have similar occupations on that point from last week that yield similar residuals with the combined data. Since I'm occupying at roughly the same time of day (lunchtime) each day I'd like some more calender days to pass, and another set of data, before I make any declarations about accuracy.
Do you happen to have static sessions (network, not stand alone OPUS solutions) on these same points?
It would be interesting to compare a static network result with your RT results.
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Kevin Samuel, post: 322763, member: 96 wrote: ...It would be interesting to compare a static network result with your RT results....
Indeed, but only if resolved using vectors from the ORGN stations. I'll likely get to that sometime soon.
it seems that a 15 second is as good as a 90 second.
I can't share too much at this point, as I'm still collecting and assessing data, but I believe you are likely correct regarding 15 epochs vs. 90 epochs. What I'm seeing right now is pointing to points collected for 4 minutes will yield about a 30% reduction in standard deviation and extreme spread over points collected for 20 seconds. Points collected for 120 epochs appears to yield about a 20% reduction in standard deviation and extreme spread over points collected for 20 epochs.
Shawn Billings, post: 322771, member: 6521 wrote: it seems that a 15 second is as good as a 90 second.
I can't share too much at this point, as I'm still collecting and assessing data, but I believe you are likely correct regarding 15 epochs vs. 90 epochs. What I'm seeing right now is pointing to points collected for 4 minutes will yield about a 30% reduction in standard deviation and extreme spread over points collected for 20 seconds. Points collected for 120 epochs appears to yield about a 20% reduction in standard deviation and extreme spread over points collected for 20 epochs.
Excellent. Thank you.
