I’m trying to see what methods would be best for my current set up and field work requirements.
I currently have an RS+ and an RS2. The field area in question is a 1,400 acre wetland mitigation bank that is kind of sort of in the middle of nowhere. Cell phone reception is spotty at best and what I do get isn’t very fast.
My tentative plan at the moment is to use the RS2 as the rover (in kinematic mode with network corrections) and set the RS+ as the base (in static mode) to collect data in one central location all day while I work in the field. Then come back to the office and attempt to use the post processing software.
Would this combination likely result in centimeter accuracy for elevations? We have plans to install actual benchmarks on the site but until then I’m trying to get some stuff done.
For vertical accuracy better then 1cm, then no. Vertical accuracy is 2 times the horizontal, at best.
And at this size the 1ppm error would grow with the baseline.
For L1 the stated acccuracy for Static vertical 10 mm + 2 ppm and Kinematic vertical 14 mm + 2 ppm. You would not benefit the extra accuracy dual band has when your base is L1 only.
These values are relative (base-rover)
May I ask for what you need such accurate elevation?
We’re building a wetland mitigation bank and attempting to improve water retention onsite in order to promote increase growth of wetland type plants. Being able to prove that we have sustained seasonal high water tables within a foot of the surface could be a key part of that. I’m just trying to be as accurate as possible so that if any questions come up I can confidently state how accurate our measurements really are. We also need to prove that we built things like low water crossings and cleared areas to the same specs that match the plans.
It also doesn’t help that this is Florida and there’s probably only a couple of feet of elevation change over the entire 1400 acre site. And some of our plans called for grading a mile long road at something stupid like a .05 percent grade.
Right. Should be like a walk in the park
At these distances with such low margins, even the best of the best would struggle to produce meaningful and credible data. Like an elevation relative to what…
One thing is to make something perfectly flat, but this is water. Its not flat, and is literally affected by everything in terms of where and how it moves.
Anyways, I am out of accuracy on this. I am sure someone els will chime in with some valuable input.
Well, its not too hard to produce some fairly accurate vertical values. E.g a 24hours ppp would produce an vertical accuracy close to 1 or 2cm almost anywhere in the world. But 1 or 2cm accurate to what?
Its “what” in relative to “where” that makes it challenging.
If you measured water levels at both ends, and one end supposedly is 30cm lower then the other end: how do you know its not the tide, moon, wind, current, erosion, Earths core any other factor affecting the height difference?
Edit:The RS2 and or RS+ might handle what you want, but I am not sure it will give you the whole truth. I think that is what I am trying to say.
Sorry if this is confusing you.
Lol, I get what you’re trying to say but we’re measuring features of a wetland (basically sectors that consist of a hundred or so acres) and taking water level readings from wells located at discrete points. Part of the issue we were having is that there was no way to tie these well data points together to get overall views of groundwater flow over the whole site.
So what we want to show is that elevation at point A is 100’ and point B is 102’. The wells constantly monitor water levels by taking readings every 7 minutes. We get a large rain event and we see that shortly after that rain, the water levels in point B are rising at the same time that Point A is dropping. This shows a relationship between the two and if we can modify the site to keep water in the wetland at point B it may help Point A grow (or vice versa).
This was just an example. I’m more concerned with installing/maintaining the wells and (now) collecting elevation data on features at our sites.
Sure, rounding of to nearest feet shouldnt be an issue. Recommende distance between base and rover with L1 is 10km, whats the distance between these wells? I would reckon the vertical error to be between 2-4cm at 10km baseline.
But then theres your connectivity, I dont think LoRa would range 8km without having line of sight.
you could connect a UHF radio of choice, that might punch through .
If you manage 2G (Edge) speed on your phone, that should be enough.
When I was at school, they said Florida is quite a wetland, and some new agriculture technologies (not sure how to name it right, please correct me) should be invented to grow something there. Cool to see how it works in real life!
But let’s leave my childhood flashback If we speak about the accuracy, I join @TB_RTK: it’s possible to receive centimeter-level accuracy with PPK at small baselines or PPP.
I’d even prefer PPP with Reach RS2. Reach RS+ is a single-band, so no benefits from multi-band Reach RS2 in this setup. You may spend too much effort while playing with PPK settings. Since you’re going to work in static and record quite long logs, why don’t you record a bit longer log for PPP?
But I’m also wondering if it’s possible to make really static measurements on wet soils? Won’t the receiver sink?
