Ok, based on some advices from Rick I used a small program from documentation to gateway all NMEA messages to u-center a software provided by ublox. Unfortunately, it exists only a Windows version, but it provides a configuration and visualization tool-suite.
HardwareSerial GPSRaw(2);
void setup() {
M5.begin();
GPSRaw.begin(9600);// GPS init
Serial.println("M5Stack ready!");
}
void loop() {
// put your main code here, to run repeatedly:
if(Serial.available()) {
int ch = Serial.read();
GPSRaw.write(ch);
}
if(GPSRaw.available()) {
int ch = GPSRaw.read();// read GPS information
Serial.write(ch);
}
}
For my application (bicycle tracking while riding and walking), I changed the movement model from automotive to pedestrian (this is important for local filtering). Additionally, if you are not interested in the altitude, you can change the fix configuration from 2D to 3D. This adaptation reduces the time for upcoming. Don't forget to burn your settings to the M8N ;-)
Unfortunately, I was not able to receive any position from Galileo. Some ideas on how to involve the European system too? Probably I have to use a new antenna?
Sebastian