Rtpk vs Rtk results - consistent 0.18’ difference in horizontal

Darren Clemons

Well-Known Member
Since the latest update and changes in rtpk, we have noticed a remarkable consistency in the rtpk and rtk results in heavy canopy areas coming up to be around 0.16’-0.20’ horizontal difference. I probably saw this at least 6 or 7 times today. In those instances, based on multiple points collected, we almost always end up getting rtk to repeat down to about 0.04’, but multiple rtpk will stay “off” about 0.18’. Most of the ones I saw today were in the west/southwest quadrant.

Has anyone else noticed anything like this or does anyone have any ideas or thoughts as to why this would be happening so consistently?

My guys have talked about this quite a bit the last few weeks and I’ve seen it in the screenshots they’ve collected, but after being in the field all day today in some rough spots and seeing it 1st hand, it definitely seems it is not “random”. It‘s just too exact of a difference on too many points.
 

Nate The Surveyor

Well-Known Member
Is the direction of the difference consistent? There was a version with some sort of problem like that. I can find it if you like.
Nate
 

Darren Clemons

Well-Known Member
Do you happen to have correct for tilts on and usually align the rover the same direction for each shot? What do you see in the open?
Correct for tilts was not on. In the open rtpk is always within 0.02'-0.04 at most. We usually orient north when collecting with the LS but with the challenging spots we put it in the woods, near trees and fence posts, that, of course, isn't feasible all the time.

I'm going to speak with another crew over the weekend, as I believe all 3 of our units have been displaying some of this consistent behavior. I am also going to recheck the rover pole I was using yesterday to make sure it isn't out a titch....

Here are several screenshots from the job yesterday. All of these points were in moderate to heavy wooded areas. Point 59, for example was an iron pin I set at the base of a large 36" Red Oak tree (early in the morning as you can also see). We were able to get multiple shots for verification on it with no problems and the rtpk agreed every time with very good residuals.

On the 1st screenshot on point 83, notice the DTL under rtpk stop. That was a 1st shot store of two matching rtpk solutions only on point 82. This rtk is "missing" it by 0.196 but this rtpk was within about 0.04' of the 1st rtpk if I toggled the current to rtpk. We ended up getting almost 400 seconds in this rtk (2nd screenshot of point 83) and then verified that with another rtk and used that coordinate. On this one, eventually, the rtpk did agree with the rtk very well.

We are just having quite a few that end up looking more like point 64. No matter how long we stay, this "0.18'" number just keeps popping up, over and over. 20210903-09.45.33_59.png20210903-10.48.00_64.png20210903-11.08.57_3_STAKE.png20210903-11.23.01_71.png20210903-11.51.11_79.png20210903-12.36.20_83.png20210903-12.41.07_83.png20210903-13.46.02_92.png
 

Michael Stazhkov

Developer
Staff member
5PLS
Since the latest update and changes in rtpk, we have noticed a remarkable consistency in the rtpk and rtk results in heavy canopy areas coming up to be around 0.16’-0.20’ horizontal difference. I probably saw this at least 6 or 7 times today. In those instances, based on multiple points collected, we almost always end up getting rtk to repeat down to about 0.04’, but multiple rtpk will stay “off” about 0.18’. Most of the ones I saw today were in the west/southwest quadrant.

Has anyone else noticed anything like this or does anyone have any ideas or thoughts as to why this would be happening so consistently?

My guys have talked about this quite a bit the last few weeks and I’ve seen it in the screenshots they’ve collected, but after being in the field all day today in some rough spots and seeing it 1st hand, it definitely seems it is not “random”. It‘s just too exact of a difference on too many points.
Darren, please send the project to support.
 
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