RTK Solutions

RTK Guidance

I use the following setup for my AgOpenGPS autosteer system with the free Iowa CORS correction service. The accuracy here in central Iowa seems to be in the 1 - 2 cm range! The correction takes place outside the autosteer system so the autosteer system is setup as a generic WAAS type antenna (but the GPS shows as RTK Fix or Float accuracy). See documentation under pictures.

I have also built a DIY base/rover setup for use on an AgLeader monitor.




DIY 3D printed dome


Under the cover


With the antenna removed


With the antenna disk removed


Base / Rover System

For NTRIP correction you will need to supply a cell phone and install an app for the correction service. I use the free Lefebure NTRIP app on an Android phone. I'm guessomg you might be able to use an IPhone as well.

On Sparkfun.com, go to Home/Tutorials/GPS-RTK2 Hookup Guide and find the "Connecting the ZED-F9P to a Correction Source.

You may need to use the free U-Blox U-Center software to configue the F9P to output NMEA GGA and VTG sentences to the serial port.

NTRIP Parts:

Sparkfun GPS-RTK2-SMA Breakout - ZED-F9P (Qwiic) $220
Sparkfun GPS Antenna Ground Plate $5
Sparkfun Bluetooth Mate Silver$28
Sparkfun GPS/GNSS Magnetic Mount Antenna SMA - 3m $13
OR the much better antenna: Sparkfun GPS-15192 - $64.95
Sparkfun Female Headers $1.50
My Plastice dome with magnetic mount: $35
Serial to RS232 conversion kit for AgLeader type use: $75
For me to solder, assemble, program: $200

You will need to buy a special data cable to go from the antenna to the cell phone (find on Amazon). The antenna end needs to be a USB type C male connector and the other end needs to be a male connector matching your phone's charging/data port. I use a USB C male to USB C data exchange cable with a USB C to USB micro converter.

DIY Base/Rover Parts:

In 2017 I used an older U-Blox C94-M8P-2 kit with UHF radio communications: $399. See https://www.digikey.com/en/products/detail/u-blox/C94-M8P-2/6150728. The kit contains 2 identical boards. One is used for the base and the other for the router. I would find a way to do it with the newer ZEO-F9P chips but the C099-F8P kit only uses bluetooth and WIFI. The WIFI won't communicate far enough for farm use. Good way might be to use Sparkfun ZEO-F9P boards and XBee 3 Pro units for radio communications.
2 Enclosure boxes @ $24. See https://www.digikey.com/en/products/detail/bud-industries/PN-1334-C/429006. I used one of these and a cheap waterproof camera case? from Menard's hunting supplies.
LM7808 chip for power regulation and prototyping board
TTL to RS232 converter if using with AgLeader type monitor: $16 https://www.sparkfun.com/products/449
12V garden tractor battery for base. Tripod. Various wires and connectors. Contact me if interested.

A second option is to look into the Ardusimple RTK system.

Lead time for me to purchase and assemble is a few weeks. Prices are subject to change as parts prices fluctuate.

To purchase parts or a system, email me at Jim (at sign) outfarming.com.