This library extends TinyGPS++ to enable sending commands to the GPS module.
TinyGPS++ itself requires one-way communication. You would use it's encode() function to pass it characters. Such data could come from an arbitrary source, not necessarily an actual GPS. However, this library requires two-way communication to both send commands and receive acknowledgements and therefore needs to connect to a stream. A very basic example boils down to:
MTK_GPS mtk(Serial1);
void setup() {
Serial1.begin(9600);
}
void loop() {
mtk.loop();
}
Please refer to the PMTK Packet User Manual for a full explanation of all the functionality. It's also worth taking a look at the MT3339 product specs. uBlox also has some interesting information.
Only a few of the available commands have been added to the library at this point, but more are on their way. Most of them are pretty easy to add.