HMC5883L compass: true north vs magnetic north with GPS correction

Customer:

I need the module to be able to determine true north (geographical), not just magnetic north. In other words, the module should be able to determine compass magnetic north and then apply magnetic declination correction (the difference in degrees between true north and magnetic north), with azimuth at 0 degrees. Someone created an Arduino module for this, but I’m not sure if I’m allowed to use that module. Can you confirm whether your module can determine true north or only magnetic north?

Original message (Croatian)

Hvala Vam na odgovoru.
Važno je da modul ima mogućnost određivanja pravog sjevera(grografskog-true north) ne magnetnog. Drugim riječima modul bi trebao imati mogućnost odrediti kompasni (magnetni sjever) te napraviti ispravku magnetne deklinacije( razlika u stupnjevima između pravog sjevera i magnetnog) odnosno azimut 0 stupnjeva. “Codegirl” je napravila/o taj arduino modul samo ne znam da li imam pravo koristiti taj modul. Link sam Vam već poslao.
Možete li potvrdti da li Vaš navedeni modul može odrediti pravi sjever ili samo magnetni?
Hvala!

Adrian

Originally submitted via email support on 27 November 2018. Migrated to the forum for community visibility.

Soldered Support:

The module determines magnetic north, since it’s impossible to determine true north with this type of sensor. However, as I can see from the project you linked, combined with GPS, it is possible to calculate and determine true north.

Original message (Croatian)

modul određuje magnetni sjever, budući da je nemoguće odrediti true-north sa ovakvim senzorom. Ali, koliko vidim na projektu na linku, s kombinacijom s GPS-om, moguće je izračunati i odrediti true-north.