Howdy, forgive me in advance, I am pretty much clueless when it comes to this stuff. I work for a pretty large water district who is intentionally pursuing GIS data collection using Facet L-Band and Diamond Maps. I saw the Point Perfect subscription was being removed in December which leads me to my question (we currently have 5 facets and will be getting more). How would I go about setting up an RTK base station, so that we can get that similar accuracy we get with point perfect.
Welcome @Matthew_Kruse! Will you have cellular reception? If yes, I recommend switching from L-Band to NTRIP. I can walk you through that. It’s ~$15/unit per month (a lot less than L-Band).
If you want to setup your own base, the hardware is as simple as an RTK Surveyor setup in your office connected to power and internet 24/7. There’s a handful of steps to get the base configured, but if the kit is ~$600. So $600 / ($15 * 5) = 8 means the base will pay itself off in about 8 months. The downside is that your surveying units (aka, Rovers) will need to be within ~50km or 30 miles of the Base. If they are out of that range, the corrections can be too low quality for the Rover to get an RTK Fix. A Base can handle hundreds of Rovers, so you can add as many as you need over time.
So, if you’ve got cellular coverage, I recommend switching to NTRIP from PointPerfect. It’s the path of least resistance and pretty cheap at $15/month. You can roam all over the US 48 without coverage issues.
If you’ve got cellular coverage, and can handle the admin of a base, we’ll dive into the details to get you there.
If you don’t have cellular reception, then we have to start talking about Startlink internet but let’s not go there yet.
We have cell coverage in most areas, it does get spotty in some areas. 30 miles would cover us if I set up the base in an central area of our system. So I’m pretty interested in the Base option. Does the base option need reliable cell coverage as well?
Got it. The base station needs only an internet connection.
Please give this section Creating a Permanent Base a read. The points to take away:
- you have to mount an antenna permanently to a structure
- configure the RTK device to gather raw data to an SD card for 12 to 24 hours
- register a caster with RTK2Go, Emlid, and/or Onocoy
- configure the RTK device to be in Base mode and transmit its corrections to the caster
Once those things are in place, all the Rovers will use NTRIP to connect to RTK2Go, Emlid, or Onocoy to get the corrections from your Base.
10-4,
I see I need a rover (Facet) to collect the raw data but once that data is collected, can that rover can go back in the field? Where does the RTK Surveyor come in?
You need some additional equipment (I recommended an RTK Surveyor kit above) to be a base. The base sits at your office until the end of time, connected to the internet. All your Rovers (Facets) then receive the correction signal from the Base while they’re in the field.
How level does the base antenna need to be? I’m planning on mounting the antenna on or near the peak of our roof, and depending on how level it needs to be makes my job harder. Also we’ve got a 40’ tower near by that will stick up past the antenna about 20’ is this a problem?
I’d say less than ~30 degrees of inclination. It doesn’t have to be super level, but it helps. More important is the fix stability: if the antenna rocks back and forth a few centimeters it will translate that directly as a few centimeters of inaccuracy to the rovers. Bolt it to the roof or use a good mag mount and you should be fine.
A 40’ tower nearby is not going to affect it much. Big buildings, mountains, maybe big trees are less than ideal, but should still work.
As an example, here is my base station in a mountain canyon:
The red/yellow around the edge shows the lack of reception as satellites drop behind the mountain range. The base still works fine, as do the rovers using it. It’s just less than ‘ideal’.