FuGPS Library

It is a simple Arduino library for parse NMEA sentences (e.g. GPS/GLONASS/GALILEO) from serial port or any other object derived from Stream class.
I wrote only a few basic functions for the simplicity of use.

Why another library?

I wrote it for fun, learning and for my next project (meteorological balloon).

Installation

This library is available on Arduino Library Manager (should be after some time).
If not, just download project from GitHub and put (after extraction) into Arduino library folder.
Library was written in Visual Micro, but can be compiled also on Arduino IDE.

Setup

#include <NeoSWSerial.h>
#include <FuGPS.h>

NeoSWSerial in(8, 9);
FuGPS fuGPS(in);

void setup()
{
    Serial.begin(38400);
    in.begin(9600);

    // fuGPS.sendCommand(FUGPS_PMTK_SET_NMEA_BAUDRATE_9600);
    // fuGPS.sendCommand(FUGPS_PMTK_SET_NMEA_UPDATERATE_1HZ);
    fuGPS.sendCommand(FUGPS_PMTK_API_SET_NMEA_OUTPUT_RMCGGA);
}

Example 1

Good for testing purpose.

void loop()
{
    // Valid NMEA message
    if (fuGPS.read())
    {
        byte tokenIdx = 0;
        while (const char * token = fuGPS.getField(tokenIdx++))
        {
            Serial.print("Token [" + String(tokenIdx) + "]: ");
            Serial.println(token);
        }
        Serial.println();
    }
}

Example 2

Typical usage.

bool gpsAlive = false;

void loop()
{
    // Valid NMEA message
    if (fuGPS.read())
    {
        // We don't know, which message was came first (GGA or RMC).
        // Thats why some fields may be empty.

        gpsAlive = true;

        Serial.print("Quality: ");
        Serial.println(fuGPS.Quality);

        Serial.print("Satellites: ");
        Serial.println(fuGPS.Satellites);

        if (fuGPS.hasFix() == true)
        {
            // Data from GGA message
            Serial.print("Accuracy (HDOP): ");
            Serial.println(fuGPS.Accuracy);

            Serial.print("Altitude (above sea level): ");
            Serial.println(fuGPS.Altitude);

            // Data from GGA or RMC
            Serial.print("Location (decimal degrees): ");
            Serial.println("https://www.google.com/maps/search/?api=1&query=" + String(fuGPS.Latitude, 6) + "," + String(fuGPS.Longitude, 6));
        }
    }

    // Default is 10 seconds
    if (fuGPS.isAlive() == false)
    {
        if (gpsAlive == true)
        {
            gpsAlive = false;
            Serial.println("GPS module not responding with valid data.");
            Serial.println("Check wiring or restart.");
        }
    }
}

Example 3

Suitable only with HardwareSerial (not tested).

void loop()
{
    // Valid NMEA message
    if (fuGPS.isValid())
    {
        // Rest is the same...
    }
}

// SerialEvent occurs whenever a new data comes in the hardware serial RX.
void serialEvent() {
    fuGPS.read();
}

Possible problems

Dropping frames (messages)

Please, don't use SoftwareSerial if you must capture more than one type of message, it is very ineffective.
You can experiment with setting proper input and output baud rate, but the best solution to me is to use better implementations of Serial:

• HardwareSerial (always the best way).
• NeoSWSerial (ESP8266 not supported).
• AltSoftSerial (pins 8 & 9 for a Nano, ESP8266 not supported).

Compatibility

I tested on that I had, it means GY-NEO6MV2 and below modules.

MCU	Works	Notes
Arduino Nano w/ ATmega328P	YES
Arduino Pro or Pro Mini w/ ATmega328P (3.3V, 8 MHz)	YES
Arduino Pro or Pro Mini w/ ATmega328P (5V, 16 MHz)	YES
ESP8266	YES	WeMos D1 mini. I had to implemenent my own strsep() function.
ESP32	YES	DOIT ESP32 DEVKIT V1

My library support also ESP8266 and ESP32, but referenced libraries don't have to!

Developing

I would rather not complicate the library by adding too many functionalities.
There are exists many other complex libraries and everyone can find something suitable for themselves.
I cared about simplicity and stability.

Debugging

There are two macros:

DPRINT(...)
DPRINTLN(...)

To use them, uncomment:

#define FUGPS_DEBUG

We don't need GPS module for testing. My library needs Stream as input, so we need some object implementing this class.
I found this: https://github.com/paulo-raca/ArduinoBufferedStreams.

Now, code might look like this:

#include <LoopbackStream.h>
#include <FuGPS.h>

LoopbackStream in;
FuGPS fuGPS(in);

const char * gpsStream = 
    "$GPGGA,092750.000,5321.6802,N,00630.3372,W,1,8,1.03,61.7,M,55.2,M,,*76\r\n"
    "$GPGSA,A,3,10,07,05,02,29,04,08,13,,,,,1.72,1.03,1.38*0A\r\n"
    "$GPGSV,3,1,11,10,63,137,17,07,61,098,15,05,59,290,20,08,54,157,30*70\r\n"
    "$GPGSV,3,2,11,02,39,223,19,13,28,070,17,26,23,252,,04,14,186,14*79\r\n"
    "$GPGSV,3,3,11,29,09,301,24,16,09,020,,36,,,*76\r\n"
    "$GPRMC,092750.000,A,5321.6802,N,00630.3372,W,0.02,31.66,280511,,,A*43\r\n"
    "$GPGGA,092751.000,5321.6802,N,00630.3371,W,1,8,1.03,61.7,M,55.3,M,,*75\r\n"
    "$GPGSA,A,3,10,07,05,02,29,04,08,13,,,,,1.72,1.03,1.38*0A\r\n"
    "$GPGSV,3,1,11,10,63,137,17,07,61,098,15,05,59,290,20,08,54,157,30*70\r\n"
    "$GPGSV,3,2,11,02,39,223,16,13,28,070,17,26,23,252,,04,14,186,15*77\r\n"
    "$GPGSV,3,3,11,29,09,301,24,16,09,020,,36,,,*76\r\n"
    "$GPRMC,092751.000,A,5321.6802,N,00630.3371,W,0.06,31.66,280511,,,A*45\r\n";

void setup()
{
    Serial.begin(38400);
    Serial.println("Setup");
}

void loop()
{
    const char * pStart = gpsStream;
    
    while (*pStart)
    {
        in.write(*pStart++);
        if (fuGPS.read())
        {
            byte tokenIdx = 0;
            while (const char * token = fuGPS.getField(tokenIdx++))
            {
                Serial.print("Token [" + String(tokenIdx) + "]: ");
                Serial.println(token);
            }
            Serial.println();
        }
    }
}