This fork adds the following features:

• Device name parameter for gps_init - Instead of hard-coding the device name (aka "PORTNAME") in serial.h, allow callers to specify the device name in gps_init. Note that this change necessarily breaks existing implementations by adding a function parameter to gps_init. However, it enables callers to easily use different devices (e.g., "/dev/ttyUSB0", "/dev/ttyS0", etc) without having to recompile the libgps library every time.
• make uninstall target - This enables easily installing and uninstalling the libgps library. Useful for testing.

The GPS library

In order to obtain libgps.a

$ make
$ sudo make install

This project is mainly created for Raspberry ARM boards. After you have compiled the source code on the target or cross-compiling you can include it in your application

#include <gps.h>

The library mainly exposes few methods

• gps_init(char *devname) - Initialize the communication. For example, gps_init("/dev/ttyUSB0")
• gps_on - Activate the GPS device
• gps_location - Expose data from GPS (latitude, longitude, speed, course, altitude)
• gps_off - Turn off the GPS device

This project abstracts all datas and replies in:

• Decimal Degrees for latitudes and logitudes (46.235325, 7.12521)
  • Not degrees (42° 53' 23.25'' North - 4° 22' 46.3'' West)
• Knots for speeds
• Degrees for angles (course)
• Meters for altitude

Create a simple position_logger.c file (you can find all in the examples folder)

#include <stdio.h>
#include <stdlib.h>
#include <gps.h>

int main(void) {
    // Open
    gps_init();

    loc_t data;

    while (1) {
        gps_location(&data);

        printf("%lf %lf\n", data.latitude, data.longitude);
    }

    return EXIT_SUCCESS;
}

Compile it

$ gcc -o position_logger position_logger.c -lgps -lm

Run it

$ ./position_logger

You will see your data directly in console:

45.071060 7.646363
45.071082 7.646385
45.071078 7.646387
45.071060 7.646373
45.071048 7.646358
45.071052 7.646372
45.071057 7.646392
45.071062 7.646397
45.071062 7.646383
45.071073 7.646395
45.071082 7.646403
45.071082 7.646403
45.071080 7.646395
45.071083 7.646392
45.071088 7.646393

You can rotate the output to files

$ ./position_logger >> position.log

That's all...

This library is tested with:

• Adafruit Ultimate GPS Breakout - 66 channel w/10 Hz updates - Version 3