I am in the same locale as @joe.gatti and our NTRIP is typically +/- 0.20ft from ground benchmarks. I can’t explain why because it has always been that way. I have seen as bad as 0.30ft and that is the point when you start finding site benchmark issue. Occasionally I will hit within a 0.10ft but that’s pretty rare and when starting a jobsite the agreeance but the Emlid and the ground needs to be 0.05ft in my opinion or we will be fighting the edge every day. Luckily we can fix it all in software but if I want to scale a program I can’t rely on other takes doing so. I can tell you that something is coming that will fix that.
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So here’s the results from my test this morning. I have 2 BM’s, BM-1 elevation=931.880 and BM-40 elevation=977.118. With my rover using the Texas network for correction I adjusted my pole height to 7.36 and was able to hit an elevation of 931.887. Set my base on that point and configure the base settings for 931.880 base output set to emlid caster service.
Tying into BM-40, still using the Texas correction on my rover, I hit an elevation of 977.171, a difference of .053, not great but under 1/10. Switched the rover input correction from the Texas network to emlid caster service, now getting correction from my base. Tied into BM-40 at 977.121, even better only .003 deviation.
I then set 4 checkpoints boxing in the site with my rover, still using my base for corrections.
Elevations as follows:
chk-8162023-1 929.987
chk-8162023-2 924.827
chk-8162023-3 923.281
chk-8162023-4 933.268
Switched my rover back to the Texas network and shot the same checkpoints again.
chk-net-8162023-1 930.040 deviation of .053 from chk-8162023-1
chk-net-8162023-2 924.898 deviation of .071 from chk-8162023-2
chk-net-8162023-3 923.498 deviation of .217 from chk-8162023-3
chk-net-8162023-4 933.400 deviation of .132 from chk-8162023-4
Wasn’t looking to bad until the last to checkpoints.
So it looks like I will continue to use my base on a know point for correction for both rover and drone.
Just had to test my theory out.
Thanks for all the input.
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How far away is the nearest CORS in this TX network for this test?
Wonder if discrepancy between the TX network and the surveyor’s set BMs? How and/or what method or equipment did they use?
The closest one is about 6 miles away from the site. Our guys use topcon, they usually run a level loop from one of the BM’s we get from the survey company. I have no idea how those were set originally or what equipment they use…guessing with topcon or trimble.
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There’s always a discrepancy between the network and the ground BM. Unfortunately in construction we have no way of knowing if the vertical they gave us is 2nd, 3rd or whatever order or where it originally came from but that irrelevant unless there is a leveling problem and still no one cares where it originated.
@joe.gatti You running network? The BM is 6 miles? Because I know anywhere in Leander to Georgetown and Round Rock is at least 30km from a CORS.
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Michael, you’re right. I was looking at the RTKnet map not the CORS map. Haven’t looked at that in a while, looks like they got rid of one. The closets ones I see are Belton and Southwest Austin, that kinda suck.
Yep, Taylor went down. You should get your guys to buy a Rock base and 1 access license which is less than RTKNET… Their network is taking off.
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I looked at that when they first announced it, guess I’ll have to take another look. Just cautious about reliability. RTKnet is expensive but I’ve never had issues connecting when I’ve need to.
We put one up at our office at 183/IH35 about 3 months ago and it is better. More channels and more constellations. They are providing Galileo and Beidou but also L5. Two more just came online within the last month in Brushy Creek and another next to Wilco Southwest Regional Park. I’m talking to a Surveyor about putting one up in Liberty Hill.
I might try their $40 a month service before I buy one just to test drive it for a while. My RTKnet subscription doesn’t run out til end of year and really all I use it for is finding BM’s and backup if for some reason I can’t get my drone to connect to my base. I’ve kinda given up on the RS2+ cellular support, half the time I have to connect it to my hotspot to get good enough connectivity.
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Curious, what is the issue for the RS2+ cellular support? Is it the RS2+ itself or poor cellular provider service or both? Have tried a pocket hotspot device? What carrier do you use?
Not sure what the issue is, I’m gonna guess it’s latency. I do have a hotspot same carrier as what’s in the RS2+. We use T-Mobile for most company provided hardware…cell phones, iPads and everything else. My cell is AT&T I seem to get better coverage with that when T-Mobile drops out.
Here’s an example, setup my RS2+ using the internal sim, check the caster web site and can see it’s online, connect my RS2 rover to my iPad hotspot, can’t get a fix. Change the base over to use my Mifi hotspot usually get a fix in under a min or so. Seem to be worse with the drone but probably more on the DJI side.
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In my experience in our area it is both. The Reach antenna is not as effective as a mobile device or standalone networking appliance and the coverage is very inconsistent in both availability and quality. It’s getting better but obviously I have been running local NTRIP for over a year for a reason. My setup is simply networking the RS2+ and DJI RC through my iPhone hotspot. As long as I remember to turn on the hotspot before turning on any of the other devices it is flawless. I have run through a cellular Wi-Fi router and it is awesome if I get into a situation where I have to be more than 30-40ft of the base but that is very rare and it is pretty easy to set a new point at where I do need to operate from.
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I’m usually not anywhere near my base when I fly the site. I have used local a couple of time when I can but that’s not very often. Kinda the whole reason this thread got started, just using the Texas network for correction instead of having to set a base. Doesn’t look like that’s gonna work for me so I’ll keep trudging along the way I’m going.
Are you thirsty yet 
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I am! But I’ll get with ya next week 
I’m not sure I totally understand but you can definitely fly RTK off the Rock network if you want. I just use it to shoot in a point for my base and local NTRIP so I don’t have to worry about fluctuation in corrections reception or data during the flight.
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… and so you don’t have to worry about losing a FIX because the BASE grew legs and walked away! 
It’s more to avoid connectivity issues between the base and the drone via caster but that too. I’ve talked to a guy that’s had that happen to him twice. Now they leave someone there to baby sit it.
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I am always within about 50ft of my base with a present under my seat…
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