sparkfun NEO-M8P-2 Hook-Up Manual page 14

The Serial Basic board should still be blinking once a second with RTCM data from the UNAVCO server. Using two
jumper wires connect GND on the Serial Basic to GND on the GPS-RTK. Next, connect TXO to the MOSI pin on
the GPS-RTK. The MOSI pin is the RX UART pin by default (when DSEL jumper is open). Jumper wires without
solder are obviously a precarious setup but we're just testing things out. Arrange things so the connection is semi-
permanent. Within a few seconds you should see the RTK LED begin to blink.
Congratulations! Your GPS module has entered RTK float mode. When the RTK LED turns off completely then the
module has solved the carrier ambiguities and entered RTK fixed mode and is outputting centimeter level
positions!
Once you have the GPS-RTK receiving RTCM correction data successfully, you can begin plan how to obtain and
deliver the RTCM data to the GPS-RTK. The options are vast and varied:
It is possible to pull get Ntrip data on an Android app and pipe it over a Bluetooth serial device like the
Bluetooth Mate Silver. It's trivial to connect a Bluetooth serial device to the GPS-RTK serial pins.
If you need maximum portability a radio link can be the lowest power, smallest footprint. SparkFun offers a
variety of LoRa radios and antennas. With the help of a microcontroller these radios can pipe data from the
LoRa backhaul over an Qwiic I2C port, serial, even SPI.
If your end application already requires an internet connection such as GSM or LTE-CAT, then a
microcontroller could feasibly connect to an Ntrip server over the internet and pipe the RTCM data over a
serial or an I2C connection on the GPS-RTK.
GPS-RTK Arduino Library
Note: This example assumes you are using the latest version of the Arduino IDE on your desktop. If this is
your first time using Arduino, please review our tutorial on installing the Arduino IDE. If you have not
previously installed an Arduino library, please check out our installation guide.
The GPS-RTK Arduino library enables the reading of NMEA data over I2C as well as sending binary UBX
configuration commands over I2C. This is helpful for configuring advanced modules like the NEO-M8P-2.
The SparkFun U-blox Arduino library can be downloaded with the Arduino library manager by searching
'SparkFun Ublox' or you can grab the zip here from the GitHub repository:
Once you have the library installed checkout the various examples.
Example1: Read NMEA sentences over I2C using Ublox module SAM-M8Q, NEO-M8P, etc
Example2: Parse NMEA sentences using MicroNMEA library. This example also demonstrates how to
overwrite the
processNMEA
module to any library, display, radio, etc that you prefer.
Example3: Send UBX binary commands to enable RTCM sentences on U-blox NEO-M8P-2 module. This
example is one of the steps required to setup the NEO-M8P as a base station. For more information have a
look at the Ublox manual for setting up an RTK link.
Example4: This example extends example 3 sending all the commands to the NEO-M8P-2 to have it
operate as a base. Additionally the
function to direct the RTCM bytes to whatever connection the user would like (radio, serial, etc).
Setting Up A Base Station
SPARKFUN U-BLOX ARDUINO LIBRARY (ZIP)
function so that you can direct the incoming NMEA characters from the Ublox
processRTCM
function is exposed. This allows the user to overwrite the