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

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

SoftwareSerial gps_begin() {
	SoftwareSerial serial_gps(PIN_GPS_RX, PIN_GPS_TX);
	// Initialise the software-based serial connection to the GPS device
	serial_gps.begin(BAUD_GPS);
	return serial_gps;
}

GPSLocation gps_fetch() {
	// The serial connection to the GPS module
	SoftwareSerial serial_gps = gps_begin();
	// The GPS message decoder
	TinyGPSPlus	gps;
	// The struct that will hold the result
	GPSLocation result;
	
	Serial.print(F("[gps] Working: "));
	uint32_t ms_last_update = millis();
	uint8_t ticks = 0;
	// 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] GPS device init failed"));
			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
		if(!gps.location.isValid()
		#ifdef SD_DEBUG_ENABLED
			|| !gps.time.isValid()
		#endif
		) {
			// NOTE: It can take a rather long time to get a lock. Just wait patiently :-)
			if(millis() - ms_last_update > 500) {
				ticks++;
				#ifdef SD_DEBUG_ENABLED
				Serial.print(gps.time.isValid() ? '-' : '.');
				#else
				Serial.print('.');
				#endif
				if(ticks > 80) {
					Serial.println();
					ticks = 0;
				}
				// Serial.println(gps.location.lat());
				// Serial.println(gps.location.lng());
				// Serial.println(gps.date.year());
				// Serial.println(gps.time.hour());
				// Serial.println(gps.time.minute());
			}
			ms_last_update = millis();
			continue;
		}
		
		// Hooray!
		Serial.println(F("ok"));
		
		result.lat = gps.location.lat();
		result.lng = gps.location.lng();
		#ifdef SD_DEBUG_ENABLED
		snprintf(result.time, 19, "%04d-%02d-%02d %02d:%02d:%02d",
			gps.date.year(), gps.date.month(), gps.date.day(),
			gps.time.hour(), gps.time.minute(), gps.time.second()
		);
		#endif
		return result;
	}
	
	gps_end(serial_gps);
}

void gps_end(SoftwareSerial serial_gps) {
	serial_gps.end();
}