Building RTK Receiver for Ag Leader steering

I’ll start off by saying i’m new to the AgOpen world, but very intrigued and want to start tinkering. I’m currently using 2 older Ag Leader Edge monitors on WAAS, one strictly for guidance and one is running OnTrac2 steering. I have 3 RTK base stations within 30 miles of me on the Ohio CORS network so might as well use them.

First project i have in mind is building a receiver to feed RTK into the Ag Leaders. Requirements for my monitor are VTG and GGA strings at 5 hz rate and 38400 baud rate. I’ve put together a list of what i think i’ll need to make it work. Looking for some input to make sure i’m on the right track before i order anything.

-SimpleRTK2B Basic Starter Kit
-WIFI Ntrip Plugin to use hotspot from my phone
-TTL to RS232 converter to send NMEA to my monitor
-Plastic case to mount it all in the cab
-USB charger to power everything

Is there anything i’m missing? Seems relatively straightforward to get it all assembled. I found this diagram that pretty much matches what i’m thinking i’ll need, as well as the wiring from my current 1500 receivers

I did something similar with a Raven Viper 4, I used an Ardusimple rtk2blite stacked on an Rs232 to everything adapter, then a Wifi ntrip master stacked on top of the rtk2blite.

Made for a nice clean setup, but what you have picked out should work also.

After looking at the Lite some more i much prefer the power port on the RS-232 adapter over a USB, so i’m leaning towards that route.

Any issues you ran into or anything you would do different?

Is this scheme also valid for trimble cfx750?

A Trimble cfx750 cannot accept gps signals from an external receiver. The only way to get GPS into a Trimble cfx750 is through the built in GPS receiver. You can’t even use a Trimble 252/262/272 or anything.

A Trimble cfx750 can do external corrections (with an RTK unlock), but not external receiver.

So far so good, having the rs232 adapter accept 12v directly is super handy. It just took some time learning in U-Center to set up the right ports and baud rates, and to learn what a talker code was. Raven required GP instead of the default GN. Thankfully Raven has a pretty decent knowledge base website. I am not familiar with Agleader so hopefully it’s straight forward.

According to Ag Leaders website they use GP as well. Ag Leader is pretty open with using different GPS receivers and have quite a bit of info on their website, so should make it pretty simple.

Be aware that Ardusimple mark the TX and RX pins in an odd manner. TX connects to TX on the rs232 adapter and RX to RX. As opposed to the usual rx to tx…

My current thoughts on that are to use a pair of male RS232 breakout connectors which would let me flip RX to TX if needed, and be able to grab power out of my current display cable to power the board. Would eliminate needing a separate power source and a switch, it would just power up with my display.

We did something a bit similar to feed NTRIP into a Topcon AGI-3 receiver, using an rs232 board and an ESP32.

Worked well. Better than the Topcon cellular modem TBF!

could someone walk through how you had the ports and messages configured so the Ag leader would recognize the serial connection? I’ve been trying to piece it together but cant get the Integra monitor to read any connection.

any chance you could show your port settings and baud rates. I’m stumped on what isn’t working on mine as the ag leader won’t recognize anything connected via the serial port.

I put it all together a while back and tested it in the driveway, but haven’t had a chance to get in the field yet. Heres a screenshot from my Edge. Once i get a chance i’ll try to get some pictures of it assembled, and upload the config file once i can find it. I was able to use a RS232 connector so the receiver plugs right into the Ag Leader harness, and powers up with the monitor.

awesome that would be great. I figured out today that I need the tractor to be moving for any sort of gps signal, but still I get an error on the ag leader saying the gps signal is diminished and wont let me engage an a-b line or anything.

even with the tractor moving it still doesn’t let me enter the serial port receiver settings.

Using f9p with Agleader you should enable “Permit COG output even if COG frozen” in Configure NMEA

Correct, that has to be enabled for the monitor to be happy. Otherwise talker ID is GP, and i believe i’m only sending GGA and VTG from the F9P to Ag Leader.

awesome, thanks for the help. The permit COG fixed the serial disconnect. I think I got all the messages and rates correct as I can set and follow an AB line now.

However, Im unsure if im receiving any rtk correction still. On my rtk2blite board the NO RTK light is off, implying the receiver good, but under the gps section of the integra its labeled ‘No Diff’. Whereas the manual says it should display RTK Float or Fix.

picture for reference

I think you don’t have RTK. On mine it shows the correction age and the satellite in the top left should be green.

Ok with my base station and rover reconfigured this is what I’m getting now.

Differential: Diff On.

I was excepting rtk fixed but maybe through a 3rd party receiver it doesn’t necessarily recognize rtk, but there is differential correction now.