Site conditions: wide open, no multipath, no canopy, and flat land.
Using survce 3.02 and a javad triumph RTK setup. Everything with the equipment connects, fixes, and works fine.
The problem is no matter what I try I cannot get good horizontal ground distances(checked with calibrated edm). I've tried everything I can think of in the software to no avail but I can't say I did everything right in the software.
Any ideas at all? The horizontal ground measurements are off by as much as .30' in 1000.00 feet which I'm not comfortable with.
This is an autonomous setup by the way and no localization used.
I have the exact same setup and my initial guess would be that you are comparing grid distances to ground distances.
I would watch this video first.
Then this video.
And then this one.
Corey
You Must Bring Your GPS Points To The Actual Ground Surface
Even just reading an elevation off of a USGS quad map and holding that for your base elvation will greatly improve your horizontal distances. GPS provides 3D coordinates and vectors that are just floating uselessly in space otherwise.
Paul in PA
I understand quite well the difference between grid and ground, that's not the problem. It's something in the software that simply must not be working properly, or maybe more likely there's a setting I'm somehow missing even after looking at all of Carlson's training. I did it the same way shown on the second video in Carlson to no avail. I used a geodetic monument as a control point both H and V and used the grid to ground feature in SurvCE and still get the few tenths difference from an edm measurement.
Edit: I was on the correct elevation
You Must Bring Your GPS Points To The Actual Ground Surface
I used the proper elevation for the jobsite...held a geodetic mon. as a vertical benchmark. I was only 40' above sea level, btw.
Just out of curiosity, but is the error a constant 0.30', or does it vary between points? I had this issue a while back but ended up determining that the prism constant setting had changed for some reason.
Seems to be constant. Remember this is RTK GPS so I'm sure no prism offset is applied by Carlson.
You Must Bring Your GPS Points To The Actual Ground Surface
How does the scale factor Carlson is using compare to the one listed on your geodetic monument?
Also, I would verify that your using the correct projection/state plane zone.
I'm aware of that...but you said you were checking it with an EDM. I'm wondering if that's where the issue lies.
Just for giggles and grins, would you please set up your total station / EDM up in your yard, and then set your prism 10 ft away, (Almost level too), and shoot the distance, and check it with the box tape?
THEN do it again, with the Carlson data collector.
THEN check back with us with your results.
Nate
Just a thought, along the same lines: check the EDM settings for pressure/temp/humidity in case there's a rogue figure there, or a mix up with units.
I'll be following this thread! Sounds like something that might happen to any of us. I have three hub and tack stations in a big triangle in friendly neighbours' fields for checks like this, might just do one shortly.
Being At Proper Elevation Is The First Step
Second step/ your GPS vectors are slope ditances from ground point to ground point.
Using your GPS elevation differences and the pythagorean theorem, reduce the GPS vectors to the horizontal distances your survey software reports. You can also check against your raw data slope distances but then you need to know the HI and HR values to get to ground.
Paul in PA
We are in suspense. What did you discover?
OVER
I almost use the same setup Donald. I use the Supervisor tablet running SurvPC. I highly suggest anyone thinking of using a tablet running SurvPC to not buy it yet because of numerous problems with Carlson software. SurvCE running the Surveyor+ seems to be the way to go. They also are having problems with production and I personally think their website is so misleading people to think certain controllers will work with their software which is not true. That was a $5000+ mistake. Anyway my H&V are fine. My problem is I have to translate the base point elevation .035/.036 to match with rover points. Carlson has a bad base setup. When I had Microsurvey this was never a problem and everything check out just fine. Microsurvey does have other problems for reason I left them and hearing rave reviews with Carlson I thought I would give them a try. Much to my surprise they are just as bad at fixing a problem. Hopefully they have more users/software engineers and problems will be fixed soon but I can tell you using "their" so called rebranded leica robot the software SUCKS right now for that too!
What version firmware you running on the Javad's? I don't think that will matter but worth a shot to update to the newest version. I have never had a problem with Javad H&V. Just the software used to control the units is my pain right now.