LoRaWAN-Signal-Mapping/iot/main/gps.cpp

#include "gps.h"
#include "settings.h"

// The GPS message decoder
TinyGPSPlus	gps;
// The serial connection to the GPS device
SoftwareSerial serial_gps(PIN_GPS_RX, PIN_GPS_TX);

void gps_begin() {
	// Initialise the software-based serial connection to the GPS device
	serial_gps.begin(BAUD_GPS);
}

TinyGPSLocation gps_location() {
	Serial.print("[gps] Getting location: ");
	uint32_t ms_last_update = millis();
	// We WILL discover our location - if it's the last thing we do!
	while(true) {
		if(millis() > 5000 && gps.charsProcessed() < 10) {
			Serial.println(F("\n[error] Failed to initialise GPS device."));
			while(true) { delay(1); }
		}
		
		// Make sure there's something to read
		if(serial_gps.available() <= 0) {
			continue;
		}
		
		// If it failed, go around again
		if(!gps.encode(serial_gps.read()))
			continue;
		
		// If we haven't acquired a lock yet, go around again
		// Also go around again if the location is the same hasn't yet been updated (GPS devices are strange)
		if(!gps.location.isValid()) {
			// NOTE: It can really take a rather long time to get a lock. Just wait patiently :-)
			if(millis() - ms_last_update > 500) Serial.print(".");
			ms_last_update = millis();
			continue;
		}
		
		// Hooray!
		Serial.println("ok");
		return gps.location;
	}
}

void gps_end() {
	Serial.println(F("[warning] Putting the GPS device to sleep isn't implemented yet."));
}