https://www.universetoday.com/146156/magnetic-north-is-migrating-towards-siberia-heres-why/ Magnetic north is migrating towards Siberia. Here’s why: The North Pole ain’t what it used to be. Well, the geographic North Pole stays fixed over time (mostly because we define it to stay fixed over time) but the magnetic north pole constantly moves. And over the past decade it’s been moving out of Canada towards Siberia four times faster than it has in the past couple centuries. Armed with data from the ESA’s Swarm satellite, scientists might finally know why: the shifting of our magnetic field north pole is caused by a titanic struggle between two competing massive magnetic plumes. Even though the Earth’s magnetic field looks just like a bar magnet, with two poles on either end, the way it’s generated is much more complex. Deep inside the Earth, the outer layers of our core are liquid molten iron. That iron spins rapidly, carrying its electric charges in frenzied circles over and over again. Moving electric charges generate an electric current, and any little changes in that electric current amplify, folding over on themselves and generating a magnetic field – one of the strongest magnetic fields in the solar system, capable of puncturing the surface of the Earth itself and extending thousands of miles into space. Please Register or Log in to view the hidden image! The complex molten core of the Earth generates our impressive magnetic field. Source: ESA Those magnetic field lines leave the Earth at the geographic South Pole (confusingly enough, what we call the “South Pole” is really the magnetic north pole, but that’s a different story), and curve and arc their way northwards before plunging back into the Earth’s crust in northern Canada. Please Register or Log in to view the hidden image! Two magnetic plumes play a game of tug-of-war, with the Earth’s magnetic north pole caught in the middle. Source: ESA more at link............
So more magnetic variation to add to any map after taking a compass reading! But how are such readings made with GPS?
I would suspect that the variables like magnetic declination and variation, are allowed for by the GPS satellites. Afterall if this wasn't the case, then positioning would not be accurate.
GPS is based on and only concerned with geographic coordinates; it doesn't have to worry about or even care about magnetic North. You only have to deal with magnetic declination if you are using a magnetic compass to orient yourself. Then you need to know the difference between true North and magnetic North for your location.
