Best constellation to use in my region?

Hi there, new to this forum!

I recently purchased ardusimple RTK3B (2X PRO + 2 calibrated survey triple band antenna+ 2 Xbee LR radio) to ideally replace my JD RTK setup (SF6000) for field leveling and tiling.

I am looking for the best vertical accuracy possible, so I was wondering if it’s there a way to determine wich constellation to choose from for my location. (Im in Canada, near Montreal) I know for sure I need to use GPS and GLONASS, but what about GALLILEO and BEIDOU?

Now why the basic settings I use, Im pretty sure Im using GPS+GLO+GAL and BEIDOU is not enabled in RTCMv3 settings, so should I enable it or not?


I’m near Trois-Rivières,

For the f9p it says 3 constellation at 10hz but I’m running 4 just fine .

With the mosaic go for 4. In my understanding it could even run much faster then 10hz.

Which software are you planning to run?
Here on the forum you will find OpenGrade3D for leveling with prescription map and OpenGrade and OpenGradeX for tile.

Right now I don’t think OG can handle more than 10hz but I was thinking about building a new machine control with Teensy.
In this version OG would output target height instead cut delta

This should give a much better control. Instead or waiting for the fix, calculate it and send back (about 150-200 ms) it will send back the target height so as soon as the GPS fix arrives the blade control will be able to calculate a precise delta.

Thanks Pat for your answer!

How your base and rover are talking to each other? (sorry not sure the exact english term)
My setup is via radio, and it seems like the communication rate is 1hz, maybe 4 constellations will be too much bandwith for them? Maybe I should be better with 4g.

For earth moving, Im still using optisurface for prescription map (I still have credits and used to that software).

I have a base station and send correction over cellular network. Correction at 1hz
I also bought a simpleRTK2B MR Radio Kit but not used yet!

With base 4-6 km away there can be several centimetre vertical variation over some time. I think it’s related to the weather, it seem worse when cloudy.

Radio 4 constellations at 1hz should work from what I read on this forum. I think you can increase bandwidth at cost of range if needed.

For earth moving you can look at this tread (grade-control).
So far I made 3 fields (13 ha) with opengrade3D all designed with Optisurface.
Are you planning to connect the GPS to some commercial machine control?

In fact, Im already doing all field grading and tiling for over 10 years, so I have everythings, but would like to improve acuracy vs my JD SF6000 GPS rtk setup.

For grade control signal will be send to a Trimble FM-1000.

For tiling, signal will be send to a Intellislope Gradient.

Theses work with standard nmea sentences? That’s cool!

For the price of these green system I would expect to be pretty accurate! :crazy_face:

Yes it’s my first tryout phase for ardusimple, since those 2 applications only need nmea sentences.

SF6000 works really well. For guidance it’s great. For field leveling it’s great too VS other AG option, but I lose accuracy a couple hours in the afternoon (always between 14H to 16H) There are less visible GPS for the system (19 in good condition, 15-16 in the afternoon).

So my wish by trying a RTK3B system is to get better performance in vertical accuracy work, since it can track about 30 sats.

Forgot to mention that when I do tiling, or field leveling, my base is always in field, so always sub 500m. What could be the radio setting I could use then to improve bandwith?

Second tryout phase (another year maybe) would be to push those RTK3B for autoguidance in my tractor (mainly JD) I would really like to be able to find a way to fool the JD controler that the signal is a JD globe, but in fact not… :crazy_face:

Then I could sell all those expensive JD globe.