Recent in accuracies...

[Nate The Surveyor]

It seems that there may have been some changes in the way the LS runs.
I have had about 5 or 6 locations, that were off by 0.25'. (the 2 shots disagreed with each other by that much)
When I first got this gear, I played hard with it. It was hard to get two shots, that differed by 0.15'. Yes, it happened. But, not often.
I know that satellite geometry can have an effect.
I know that there can be other factors.
But, this happening to me this much, in the last 2 days of field work, concern me.
Did anybody make changes in the LS?
It does seem to run faster... but did this come at a price?
Keep up the good work.
Just wondered if others were seeing this, and if settings were internally changed in the LS, and if perhaps we, the end users, should be aware of anything, and if we should make our setting more stringent?

Thanks again.

N

 

[Donald E Robinson]

What are you using the check the shots?

 

[Nate The Surveyor]

Just against the next shot.
Some of these, I'm just spending excessive time, (15- 20 mins) and they are not is real bad places.

 

[Nate The Surveyor]

I'll post process in the morning, (dpos) and see if it yields anything.

 

[Nate The Surveyor]

I should have worded that, "excessive shot spread"

 

[Nate The Surveyor]

I have tried Dpos-ing these shots. I have tried several methods. It refuses to perform Base to Rover processing.
I have rebooted the LS. I have tried processing rover against the CORS. and still, no go.

 

[Matt Johnson]

I have tried Dpos-ing these shots. I have tried several methods. It refuses to perform Base to Rover processing.
I have rebooted the LS. I have tried processing rover against the CORS. and still, no go.

Where is it getting hung up at?

 

[Nate The Surveyor]

Everything looks good... but when you go look at the points, all that shows is RTK.
For the base, it is a repeat base site, (was previously dpos ed.) So, both are showing, for the base, ie, KNOWN, or FIXED. The shift is very small. 0.037'

So, to answer your question, at the DOPS end, it looks fine. At the Points screen, they simply do not show.
Thanks
N

 

[Matt Johnson]

Could you post the project archive on here? Don't include the Raw Files when archiving so that it can be uploaded here.

 

[Sean Joyce]

I just had this happen to me also. I tried to CORS process some points as a general check on a really bad spot in the woods.
Everything appeared to be a go but the CORS solutions do not show.
I would post this project archive but every time I go to post any type of file I get an error message.

 

[Nate The Surveyor]

Sean, did yours process base to rover?

 

[Sean Joyce]

Sean, did yours process base to rover?

Nate
I just checked my job again and the CORS solution did work with my base, (but not the NYRTN base) at least enough to verify my points, my mistake.
I failed to click to the right screen to view the solutions.
I had a few other convoluted things going on with the points I wanted to CORS process.
I set my base up in the open on the front of an 80 acre survey that went up a hill through heavy woods.
The rear line crossed over the backside of the hill and I lost radio contact as I went north.
I knew there was a cell tower close by with a strong signal so I jumped on the NYRTN with my phone in hopes of getting RTK solutions on a few points. The RTK didn't work out so well because of the heavy woods but I collected a bunch of static data with the NYRTN base info. (I don't know what I was thinking because it would surely confuse DPOS with 2 bases in the same session).
After I realized this, I hiked up to where I could establish radio contact with my base to verify I was back in beast mode with my base and then went back and collected static data on the 2 pins I needed. This was a really bad spot on a steep eastern slope and heavily wooded with Hemlock trees. (Pictures would not do the site justice, the L.S.saved me a massive amount of nasty traversing) Between my base PPK solutions, the CORS solutions, and work by other surveyors to check against I made out well. Hybrid RTK is awesome. It would have been even better if all the static data I collected on the 2 points against the NYRTN base could somehow be processed, at least with CORS. The RTN base was close by only 3-4 miles away.

 

[Darren Clemons]

Nate
I just checked my job again and the CORS solution did work with my base, (but not the NYRTN base) at least enough to verify my points, my mistake.
I failed to click to the right screen to view the solutions.
I had a few other convoluted things going on with the points I wanted to CORS process.
I set my base up in the open on the front of an 80 acre survey that went up a hill through heavy woods.
The rear line crossed over the backside of the hill and I lost radio contact as I went north.
I knew there was a cell tower close by with a strong signal so I jumped on the NYRTN with my phone in hopes of getting RTK solutions on a few points. The RTK didn't work out so well because of the heavy woods but I collected a bunch of static data with the NYRTN base info. (I don't know what I was thinking because it would surely confuse DPOS with 2 bases in the same session).
After I realized this, I hiked up to where I could establish radio contact with my base to verify I was back in beast mode with my base and then went back and collected static data on the 2 pins I needed. This was a really bad spot on a steep eastern slope and heavily wooded with Hemlock trees. (Pictures would not do the site justice, the L.S.saved me a massive amount of nasty traversing) Between my base PPK solutions, the CORS solutions, and work by other surveyors to check against I made out well. Hybrid RTK is awesome. It would have been even better if all the static data I collected on the 2 points against the NYRTN base could somehow be processed, at least with CORS. The RTN base was close by only 3-4 miles away.

Great description Sean of a job that really shows just how versatile the Javad equipment really is!! RTK, then RTN, then back to base radio and collect PPK. Just nothing else out there with that kind of versatility.
I did my first strictly PPK base/rover in the field last week off my phone. Got two points and adjusted to a survey I'd normally would have had to go back to the next day.

 

[Darren Clemons]

I have had about 5 or 6 locations, that were off by 0.25'. (the 2 shots disagreed with each other by that much
But, this happening to me this much, in the last 2 days of field work, concern me.

So these are back/back RTK shots not an RTK shot vs a PPK solution?
That is concerning.
What version of J-Field are you running, release or testing? I think pre release and release are the same as of Monday unless a new version has been moved into pre release today.
I'll definitely check a few tomorrow and see what I get. I always collect my full 3 phase shot, store it, then immediately hit start again and check "distance to last". I usually only let it run 10-20 epochs as it most always comes up 0.02' every time.

 

[Nate The Surveyor]

Darten, these are back to back rtk shots.
Some have time separation. But there is no ppk, because that has malfunctioned.
My base was set at 15.2 ft. Both days. I have a 25 foot hixon pole. I had it up two segments. Nixon makes a fine product. It has a hixon bipod, which was tied securely. Set carefully. The 2 dpos solutions for the base agreed by 0.037' northings, and 0.00 earrings.
However, would a tall base affect things?
I'll post pics later of the base. I'm on my phone posting this.

 

[Darren Clemons]

I don't think the tall base would have any affect. Is the 0.25' horizontal or vertical?
Were all the points on the same site or completely different locations?
I think certain sites with heavy interference could possible cause results like these, but if you were on completely different locations then that would probably throw that theory out the window.

 

[Nate The Surveyor]

All the poor repeat-ability shots were on the same job. There was a cell tower, about 800' away.
In the first image, which is looking East, just to the right of the T-2, you can see a small older cell tower. (it is barely visible)
In the second image, you can see the Larger, newer cell tower. These towers are both about 800' away from my base.
The last image, shows my Hixon Prism Pole, with Hixon Bipod, and it is anchored with rebar, and and is quite stable, and repeatable. It is 15.2' up.
The problems I am having, are HORIZONTAL differences. Not Vertical.
Shawn Billings mentioned that possibly having the T-2 that high, would cause Multipath. (I assumed that higher, and clearer sky, would be good.)
Anyway, Any help you can provide, as to WHY these points are differing this much, would be appreciated.

This base site is up on a high mountain. So steep, that you almost cannot drive to it. This was the only site, that worked well, to shoot shots on BOTH sided of the mountain. With active RTK.
I will confess, feeling kicked in the stomach. The worst horizontally was 0.33'.
I tied the top of my prism pole to a tree, and rotated it 180°, to check it. It was a little off. Maybe as much as 0.05' at 8 or 10 ft up.

Shawn suggested that maybe I had corrections for tilt on, and that is was out of calibration. No, Corrections for tilt is off, in all my settings, except lift and tilt. (user profile).

I'm telling you every thing I can think of that could cause problems. The horizontal dithering seemed to be a constant problem on this job.



Nate

 

[Matt Johnson]

If there was any wind I think you would get some deflection of the pole with it being that high. I would still like to see the screenshots from the points.

 

[Nate The Surveyor]

Very little breeze. Legs were tied to rebar. Tip was on a RR spike, with a cross carved in it with a grinder.
It was very stable.
It would relieve me greatly if that were it.

 

[Darren Clemons]

If there was any wind I think you would get some deflection of the pole with it being that high. I would still like to see the screenshots from the points.

After seeing your pics Nate, I would have to agree with Matt. It would not take much at all to get just a tiny bit of movement within the poles/segments. When I mentioned the base height I was thinking, at 15' high, you had it mounted onto something. I have, in the past, put my old Hiper GA's on top of a couple of building with brackets and 5/8" bolts.
That being said though, your 2 Dpos base results within 0.037' tend to say you were plumbed up solid on the point both days.

Maybe Shawn's mention of multipath with it up that high is the problem, especially with the cell tower that close.

Anyway, maybe try setting back on your base at a more standard height and try a couple more repeat shots on the ones that you have that are off.
Then check some points on a completely different site to see if they all check ok.
If it was me, I'd want to see similar inaccurate results on a completely different site to think it was something in the LS and not something specific to this site and/or the setup.