4000 lines of mostly comments and printf statements along with a 2kb coefficient file.
You only have 2k of data space in the uno so no chance.
I suspect you mean magnetic deviation (difference between true and magnetic North)declination is the angle the local magnetic field makes with the horizontal(I theenk!)
If the GPS can be oriented in line with the vehicle's axis and a magnetometer/compass (is there a vehicle?) then heading bearings can be used to calibrate the declination. Assuming the compass has compensation for nearby iron masses...
Maybe the easiest thing to do is to get g different GPS that outputs the declination.
oopssorry for mis-informationbetter to have everyone think you're a fool than to open your mouth and prove it
Why not just find out what the magnetic declination is for your area and adjust for it in your code? For example: my location in Ohio is 8 degrees 15 minutes west of grid or true north so I would just add 8 to my azimuth to find grid north. Depending you exact your direction needs to be, you could use decimals. Don't forget to convert minutes to a decimal. multiply by 1/60This will use your ip address to give your magnetic declination:http://magnetic-declination.com/