Accuracy under canopy

I have a prospective job for a timber company. I own 1 RS2 unit that I have only used to post process single point data. They are planning on thinning along a 2-1/2 mile stretch of property line. They are willing to accept a 10’ safe line so I am looking to obtain an accuracy of about +/- 5’. The canopy is 50 % deciduous, 50% conifer, averaging around 80’ high.

My question is this. Let’s say I purchase a second RS2 unit and place it in an open sky environment, communicating with my rover unit. Does the rover have the ability to let me know when I have collected enough data to achieve my +/- 5’ of accuracy under the above conditions? If so, what kind of confidence could I have in the results?

It sounds sketchy, but could only be determined on the ground. As long as you have a float or RTK fix you can be assured that you are in that tolerance, but it goes single you will be back where you were. On a good note you can setup logging on both units and PPK the results which should give you much better data, but it will be obvious where any trouble spots are.


Thank you so much for your quick response. Lacking experience with using 2 units, are you saying that if my rover reported float or RTK results, it would also report a measure of accuracy out in the field? Or would it only report a result if the solution was survey grade accurate?

On the other hand, If a particular point would only record as single, would there be any way of estimating how long I would need to collect data there in order to increase my chances of getting good PPK results?

I appreciate your help in helping through my lack of knowledge in this area.

If you are using Reachview it shows your status as you rove around and as you are taking a shot. You can determine from the values provided or in this case just make sure it is at least a Float (yellow) or better a Fix (green). If it drops to Single (red) then you will probably need to supplement with some PPK values. We can get to that if needed. Be patient though. The connection can drop, but sometime if you move around and manipulate the rover you can get it back for long enough to get the point.

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Without having an exact comparison, I used a single RS2 unit last week to walk a long property line. It was on a family member’s property we wanted to flag at regular intervals, so I wasn’t really concerned with perfect accuracy as it was in no way a professional job.

The entire lot is a mix of deciduous and coniferous of about the same height as with your case and I was able to get a fix solution most of the time. My baseline was on the longer end, at 33km, but I was using RTN and didn’t need centimeter precision. Still, I was way inside 5’ when I went over a known corner.

We started from an existing corner pipe and met, along the way, temporary stakes from the neighbor that’s currently building. Everytime, I was very close to that surveyed stake, even with the suboptimal setup.

But then again, the solution quality will vary greatly depending on other factors like satellite geometry too so I would take my experience with a grain of salt.


Thank you for your input gentlemen. I much appreciate your feedback and time…

Hi @plsurveying60,

I want to point out that the Float solution status mostly means the rover receives corrections from the base. In case you work under dense canopy, the accuracy might be in several meters, even with Float solution status.

I’d suggest relying on a Fix solution status since it always provides centimeter-accuracte coordinates.

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