Just yesterday I completed a traverse in a local suburban neighborhood. The process was to hit all the points with GPS, then traverse through them all, and simultaneously adjust the vectors and traverse data using StarNet.
The "entered provisionals" are the coordinates as determined by GNSS alone, using a Leica GS18 base/rover pair (2 x 90 second RTK observations on each point) . I've set the GPS vector standard error scaling higher than need be, to more heavily weight the traverse data. The neighborhood is not deep woods, but there is plenty of obscured sky.
why 90 seconds? Just curious.
why 90 seconds? Just curious.
I've been watching the coordinate quality statistic as it counts down, and I've reached the conclusion that by 90 seconds the improvement vs. time graph has really flattened out. As you can see from the posted results it doesn't seem to be too short a time. I very likely could go with even shorter occupations, but 90 seconds is about right to give me time to take care of little housekeeping chores, like making notes and shifting cones around, etc. in any case. So going shorter wouldn't increase production.
welcome to the present
My major point is that good performance under obscured conditions is not unique to Javad. A secondary point is that "deep woods" means different things in different parts of the country.
My major point is that good performance under obscured conditions is not unique to Javad
That is a recent phenomenon. Back 6 yrs ago, javad was the only one that had the algorithm to consistently work in heavy trees.
That said, it still has algorithms that make it a top performer in the worst environment possible. AND check itself.
The common fix/float system still gives wrong answers when sat configuration is poor, and sat count is down. It is easier for a bad shot to slip through, without a process to prevent it in place
It can be mitigated by multiple observations, over a time span. But it's not automated. But Javad is.
It is my personal opinion that you can still get wrong answers from all gps units. But Javad has the most automated system to eliminate this.
But, it's other cogo still needs improvement.
A workaround is a laptop in the truck. But, that's cumbersome. Imho.
It's mind expanding to see it work.
N
@norman-oklahoma my point is that the results you are seeing have been possible for years now, and yes, it is possible with various vendors and manufacturers. People have been saying that if you work in canopy, the only solution is a total station, even recently. Even in this thread! RTK has been functional in canopy for years, but you refused to take the word of other professionals. In many instances (not all) RTK is a better solution in canopy than a total station traverse. Errors don't compound in an RTK survey the way that errors in a total station traverse do. Navigating to and measuring a point is less cumbersome which can encourage getting extra points that simply aren't practical with a total station traverse (walking fence lines, catching remote boundary points beyond the subject boundary, such as section corners or monuments that define senior lines).
RTK is still pretty poor vertically compared to a total station, particularly under canopy, and vertical features, like building corners, can still be collected more efficiently and more precisely in many cases with a total station. So there are certainly times that a total station is the superior tool. I love my robot.
Seriously and without sarcasm or sanctimony, I'm happy to know that you have seen for yourself that RTK can deliver quality results in trees. Those residuals are outstanding. From a business sense, using RTK properly in canopy can really improve profitability and from a professional sense, it can improve the quality of a surveyor's deliverables as well.
Some of the slowest places is between 2 buildings, and the like.
Which is what you would expect - building lines define an "absolute" canyon, outside which you will NEVER get a view. There will always be small gaps in all directions under the tees which will let a signal through for a short period at some stage.
This is the best unit I've found hands down.
Chris, we don't get much "urban canyon", but we have experienced tank farms and shipping container yards. Very limited sky, and what I assumed was severe multi-path. We have not purchased new equipment in a while so the total station is always used in those conditions, we just do not trust GPS results. Are any of you using modern GPS in high multi-path conditions successfully? It would seem that a good software engineer could filter out multi-path.
We have worked a lot of trees and brush and rely on that signal getting through. Sometimes the gun finds the target with the laser. I never counted on wind blowing a few leaves with the GPS, I just assumed it takes a while to solve ambiguities in tough conditions or the satellites need to move into view. Now you will have me hoping for the helpful breeze. Does checking the wind forecast become part of mission planning? Den
@NormMiller
And. if you hang around too long, After using said chainsaw, you might meet this little gal!
Nate
We have not purchased new equipment in a while so the total station is always used in those conditions, we just do not trust GPS results. Are any of you using modern GPS in high multi-path conditions successfully
There have been some huge improvements in receivers in the past three to five years. Trimble's R10-2 or R12 are their example, but all the manufacturers have their equivalents.
They really are a whole step ahead. Not perfect, but pretty darned good.
You should try to borrow one and test it for yourself.
Yikes. It looks like someone just asked her the same question.
All seriousness aside, I used a multi-constellational Network receiver a friend of mine put together in canopy last fall and was impressed with repeated observation results. Not like the old days at all.
Does checking the wind forecast become part of mission planning? Den
No. It does behave differently in wind. But, overall, not alot of difference.
I don't have personal experience with anything modern, except Javad. Other brands operate differently, so it may affect them.
@Norm, I have had landowners get angry over a torn leaf, on their tree!
But, that image was too cute, not to share!
N
Couple weeks ago I set some control on a site. Checked each one and all was good. Gathered some locations and topo and couple hours later checked in again and all was still good. Few days ago went to check in to get some more locations and topo and the two of the points took awhile to fix and was off by .08’ - .09’ east horizontal. I’m guessing satellites were different (different time of day) and I was getting multi-path from something.
