GPS and RTK
Ditch Assist needs an RTK fix to put the cutting edge on grade. Start here: RTK, base, rover, corrections and Float in plain words, then set up your receiver, base and corrections.
Ditch Assist® has to know where your cutting edge is to within a fraction of an inch. Ordinary GPS can't do that on its own: it can be several feet out. This section explains, in plain words, how the GPS gets that close, and walks you through setting up your receiver.
Six words you'll meet
| Word | What it means |
|---|---|
| Receiver | The GPS unit: a dome-shaped box that listens to the satellites and works out where it is. |
| Rover | The receiver on your implement. It moves up and down with the cutting edge. |
| Base | A second receiver that sits still on a tripod. Because it doesn't move, it can tell how far off the satellites are right now. |
| Corrections | The base's messages to the rover, about once a second, by radio or over the internet. |
| RTK Fixed | What you get when the corrections work: the rover knows its position to within a centimetre or two. The GPS badge in the app shows a green RTK. It's the only fix to survey or grade on. |
| Float | Corrections are arriving, but the rover hasn't locked on yet. The badge shows an amber FLOAT. Wait for RTK. |
- Base. On a tripod over a marked spot, for the whole job.
- Radio corrections. Need line of sight. Stay within 2 miles of the base.
- Rover. The GPS receiver on the implement.
- Network RTK. Instead of your own base, corrections over cellular.
- Benchmark. Base moved or restarted? Calibrate to it again before you grade.
Where to start
I have an Emlid ReachRS3 or RS4, as a base, a cabled rover or a Ditch Assist Lite rover. The app can set it up for you.
I have another receiverJohn Deere, Trimble, Case IH, Outback, or any receiver that can send its position down a cable (an RS-232 NMEA output).
I'm setting up a baseWhere to put it, how to power it, and why it must stay put.
It won't get to RTKStuck on FLOAT or GPS, or RTK keeps dropping.
Most GPS problems are one of four things
- The receiver isn't sending the right messages to the control module. See What your receiver must send and Read the Status 2 light.
- The corrections aren't arriving from the base or the network. See Corrections.
- The base has moved or been restarted, so elevations have shifted. See Same base, same spot.
- The antenna can't see enough sky. See Sky view.
Everything in this section
Understand it
- RTK explainedBase, rover, corrections, and every word on the GPS badge, in plain words.
- Receiver requirementsGGA ≥ 5 Hz + VTG, 38,400 baud, RS-232, everything else off.
- CorrectionsOwn base over radio, NTRIP, Emlid Corrections, and correction age.
Set it up
- Base stationSite, mount, power, radio, and what to do when the base moves.
- Emlid Reach RS3 / RS4Base, Rover and Lite Rover presets: what each sets, from the app or by hand.
- Emlid DiagnosticsCheck a Reach's setup and set it up as Base, Rover or Lite Rover in a few taps.
- John Deere StarFireSerial Port tab on the display, then the DGPS-on-RTK case.
- Trimble and Case IHNAV II / III, Pro 700 / IntelliView 4, and the Trimble 372.
- Outback and other receiversGeneral NMEA setup steps for Outback and any other receiver.
- Bluetooth GPSSurvey with a Bluetooth receiver: pair, connect, and the limits.
Check it
Did this answer your question?
Thanks. That tells us which pages to improve.
Still stuck? Talk to a product specialist. 1-833-DITCH-AS · support@ditchassist.com · Monday to Friday, 8 a.m.–5 p.m. Central.
Calling about a problem? Send your app logs first so support can see what happened.