Parse RTCM 3.x correction data from serial input

#rtcm #serial #python #gpsrtk

This article illustrates how to parse the RTCM 3.x correction data from serial port input of your GPS base station module.

Prerequisites

Have RTCM 3.x correction data streamed correctly from some serial port of your GPS module
Have python3 and pip3 installed
CLI

Getting started

First, you want to know which ports are used by your GPS base module. Run this code (The resource was found here).

Run python3 NAME_OF_CODE_1.py

import sys
import glob
import serial


def serial_ports():
    """ Lists serial port names

        :raises EnvironmentError:
            On unsupported or unknown platforms
        :returns:
            A list of the serial ports available on the system
    """
    if sys.platform.startswith('win'):
        ports = ['COM%s' % (i + 1) for i in range(256)]
    elif sys.platform.startswith('linux') or sys.platform.startswith('cygwin'):
        # this excludes your current terminal "/dev/tty"
        ports = glob.glob('/dev/tty[A-Za-z]*')
    elif sys.platform.startswith('darwin'):
        ports = glob.glob('/dev/tty.*')
    else:
        raise EnvironmentError('Unsupported platform')

    result = []
    for port in ports:
        try:
            s = serial.Serial(port)
            s.close()
            result.append(port)
        except (OSError, serial.SerialException):
            pass
    return result


if __name__ == '__main__':
    print(serial_ports())

Then, time to parse the streaming RTCM correction data:
(resource code from here).

Run python3 NAME_OF_CODE_2.py

Should update the serial port name and the baud rate of your application

from serial import Serial
from pyrtcm import RTCMReader

stream = Serial('/dev/ttyS10', 921600, timeout=3)
rtr = RTCMReader(stream)

for (raw_data, parsed_data) in rtr: print(parsed_data)