I'm not sure whether this project is still alive, but in the attached code for an arduino atmel328p I have the adafruit GPS chip, a 16*2 LCD display and a Bosch pressure sensor on i2c. If you go through the code then there is somewhere the routine DoScreen5 which shows you how to calculate a variable azimuth, that is the variable you need to control your leds. Well, in my case I simply print it in the LCD display, and it is calculated for the current position relative to home or a waypoint depending in what screen you are. It is about the maximum that can fit in the atmel328p chip. On a moteino you don't want to run this code because Felix used port 2 and 8 to 13 for the RFM module and the serial flash. But pull the LCD driver out of my sketch, and also the BMP code, and you probably get very close to the point where you want to be. Use the adafruit library as in this sketch, and trigger on the pps to synchronize with the second tick marks. Neat device the adafruit gps board.
