Maybe I’m too dumb but it is difficult on the product page ( SparkPNT - Positioning, Navigation, and Timing - SparkFun Electronics ) to find out 1) which products are current, 2) what the intended use case is for the products. Basically - there is no “product comparison”. I want to use Sparkfun instead of something like Trimble because it’s open source but it’s hard to get an answer from Sparkfun vs dealing with Trimble’s sales folks who gladly just tell you what’s going on (I just got pointed to this forum by Sparkfun). I am looking to try out a Sparkfun RTK surveying setup with at least 1) a base, 2) a rover, 3) NTRIP corrections, 4) tilt compensation. Can someone help me out here?
Sure - I’m assuming you’d like an all in-one device? The new models here SparkPNT Facet FP - SparkFun Electronics all have -T version (scroll way down to see 6 models, 3 are -T “tilt” models). These represent our most capable RTK devices to date! Scroll a bit higher up to see this rough quick-comparison
All of these will work as either a base or rover (basically any of our products with RTK or PNT in the title can be base or rover, except the DA10N from your link).
We also carry versions of all of these varying combinations of included batteries, form factors, screens, etc (or, some without any!), but very few have tilt compensation. Here are the others
Torch (waterproof, fun form factor)
X5 + IM19 breakout
We carry more but they are out-of-stock right now, so I’ll save making this more complex for now.
Let me know if you want links for the more DIY (less plug-and-play) devices!
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As @TS-Russell said, most of the RTK lineup will meet your first 3 requirements.
Preference between the models will depend on your mission.
I’ll add the TX2 into the mix, if you will mainly use a NTRIP correction. This form factor is rugged. The TX2 does not have Tilt Compensation (but the Torch does). I think the TX2 is the best value for typical use cases 
Hi @pugglewuggle - The forum says you were last here 13 years ago! Welcome back!
Here is a page for our breakout board comparison (as well as a few RTK devices). Here is a page comparing the PNT models. Give it a read, it’s a lot, and please keep asking questions!
Thanks for the replies. I did see all of that. Is there a reason I should choose one of the Facet FP models over the others? I definitely want one with tilt compensation. Do these FP models pretty much obsolete the Torch with respect to accuracy and using it for years to come (for use as a rover)?
Do these FP models pretty much obsolete the Torch with respect to accuracy and using it for years to come
We will continue to sell the Torch but it is being sunset. The FP is our main focus going forward.
I see. Is there a reason I should choose one of the Facet FP models over the others? Do they have to be matched (both base and rover be the same model) or will they work with different models? Would one make a better base and another one make a better rover? It doesn’t seem to be clear what the pros and cons of each model are, or the benefits of one over another. If it makes a difference, I will be operating north of 65° N latitude.
@sparky I meant to reply to you, maybe it didn’t notify you. Thanks for the replies thus far!
It’ll depend a bit on your use-case. Let us know if you have any more specific needs
Are you going to be using it somewhere without cell coverage?
Sometimes with cell coverage, sometimes without. I know that I need coverage for NTRIP. Generally, I would expect to be using it with both a base and a rover with NTRIP.
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For places without access to an internet connection we recommend a PPP service like PointPerfect Flex | u-blox (if your area has coverage! See https://www.u-blox.com/en/pointperfect-service-coverage)
In this case if 3-6cm accuracy suffices you’ll just need a u-blox RTK module (rover) + a subscription and a clear view of the sky (acts as base)
Is your area covered?
Unfortunately there is no coverage according to the Ublox link. I really need better accuracy than that.
Furthermore, regarding model selection, there seems to be no clear “use this model for this purpose”. I understand the different GNSS modules have different features - but - there is no clear explanation anywhere in any material I’ve seen about why to pick one model over another. Can you help me understand the “benefits” of each model over the other two?
Can you share more specifics on your Goals?
Do you need accuracy, or just precision ?
IE: If you truly need cm accuracy (and NTRIP access to an existing network isn’t an option), then you will need to commission and operate a Base Station. That takes weeks to commission and properly validate. But if you only need relative precision at a project site, that is much easier to accomplish
It’s personal preference, with some technology drivers.
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The Mosaic X5 is the best receiver of the 3. It’s also the winner for PPP workflow.
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The X20 might be the best choice for some, depending on if you need the future L-Band Delivery from ThingStream, etc. It’s highly tied to ThingStream Services, but that’s not a requirement.
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It’s also true that most users wont notice a difference in the 3, depending on your mission.
The Base and Rover do not have to be a matching set to operate, however it is beneficial if you are chasing mm’s.
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Thanks for the reply. Ideally, both precision and accuracy, right? Haha. I am not a professional surveyor, but I am looking to come in after the professional surveyors mark lot edge monuments and lot lines and do the following: I am looking to map tracts up to about a 1/4 section, but typically 40 acres or less (individual lots will often be 2 acres or less), and get a TON of points (a grid of points not more than a few feet apart) to generate a 3D model of the land to then efficiently design a drainage plan, roads, and building/water/sewage placement (sewage and drainage are more critical since more accurate grades are needed to work correctly). Once the design work on that is done on a computer, I plan on using this to locate and stake and paint lines on the ground for all of the above items. There is a local government-operated NTRIP station planned, located about 10-20 miles from where I will do most of the work. I will have cell coverage most of the time. Another goal would be to keep locations of buried items in GIS and be able to walk up to it in 20 years (with the aid of a GPS receiver, of course), dig to more or less exactly the recorded depth at the recorded location (I would plan to put the pole with the rover on top of the item before burying it and tag the location), and find the buried item right where it is. Grade for buildings and other more “local” construction would obviously be shot with a laser transit, but this would be used to mark locations as things are being constructed and record them in GIS. Any other suggestions?
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Great reply, I love it !
Since you are obviously experienced in Civil Design - we can drill down into the discussion 
Two factors come to mind: a CORS and the Reference Frame.
Once the CORS is operating, life gets easier. You load your preferred Geoid into the data collector “once” and get to work. If/When you change correction sources, it’s a bit of work to confirm/align the results.
Note: GNSS receivers have a built-in Geoid (highly decimated) to provide approximate Ortho Heights. Those don’t have the resolution you need. That’s why I mentioned loading a Geoid in the data collector software.
Your application is a good candidate for building your own CORS. Would you have access a site to install your own permanent base, with existing LAN or WiFi access ? If so, would you consider a GNSS board (postcard, etc) and simple weatherproof enclosure for a permanent base? That gives you ultimate control over your work for the next 20 years. Sparkfun has some great guides for building and operating DIY permanent Base Stations. Life is easier when you don’t have to setup a local base just to locate a new valve in the ground
Thanks for the response. Unfortunately, leaving a permanent base station on-site at these locations is not possible. A temporary base is the only possibility. I would need to set up a local base station when coming out each time, which should not be often. At all of my proposed sites right now I do have good LTE/5G cell coverage, but none of the commercial NTRIP/PPP services that I am aware of (U-blox/etc.) have coverage here. I could possibly use a government operated NTRIP station that is proposed about 10-20 miles from my location
I’m glad you brought that up. I didn’t think of that. I understand the standard geoid is for the entire world and thus does not take localized variations of the earth into account very well (what you said). Do you have a recommendation of what kind of geoid to load? (And an example of software to do that with?) Would that work on both desktop GIS software and also my iPhone with whatever mapping app I’m using in conjunction with the rover (I assume so)? Being that I’m in Alaska, would something like this be what I’m looking for or something else GEOID12B ? There is a list of NOAA geoids here NGS Geoid and Deflection Models, but honestly I don’t know what I’m looking at.
Yes, Google confirms Geoid12B for Alaska (for now).
If I had to guess, I’d say the local surveyors in Alaska will likely use the State Plane Coordinate System (SPCS) for the 2D projection.
Since NGS is right in the middle of the official transition to the new National Spatial Reference System (NSRS), it’s hard to decide on which system to use for a new project.
But since NSRS isn’t finalized right now, it’s not really a choice…yet.
Now, on to the fun stuff:
Will you publish Grid or Ground Coordinates?
IE: When we locate 2 points with GNSS, the distance between that pair of coordinates is not the same as when measured with a total station, tape measure, etc. To transition from Grid-to-Ground requires knowing the Scale Factor for that location.
Since you won’t be staking-out anchor bolts for a rocket launch pad, Grid Coordinates (SPCS) should be fine, and makes your life much easier in CAD
Here’s a reasonable example for setting up and documenting a Project:
- Horizontal Datum: NAD 83 (2011) Epoch 2010.00.
- Coordinate System: Alaska State Plane (pick your Zone).
- Vertical Datum: NAVD 88.
- Geoid Model: GEOID12B.
- Units: US Survey Feet
The Quickest way to start a local base would be to find a published control point (adjusted network solution) from NGS and setup your base there. The Holy Grail would be a first order Horizontal & Vertical position.
If you cant find a nearby (network adjusted) solution, then OPUS would likely be your next choice, by post-processing using existing CORS. Establish permanent threads for your antenna and start logging. Once you have an OPUS solution that you’ve verified across multiple missions, those threads are your Base Location from now on.
Another route to consider is to find and use a surveyor’s existing local control at the site, but check it. You will want to locate/consume any local control anyway.
You could also try TopNet Live which is Topcon’s global GNSS correction service. I used TopNet for years, but obviously not in Alaska. If your location is covered by TopNet’s network, that’s an easy button for sure.
The app you use for data collection is probably the most important choice to make. Unfortunately, we don’t have a lot of “great” options for iOS for Civil Work.