The lowest the anomaly comes to the surface is 200 km and it's called South Atlantic for a reason. It's not a global, but a local thing. How does GPS navigation work? The receiver calculates its distance from 4 or more satellites. We have 31 operational GPS satellites up there at the moment, 9 in reserve and 3 being tested. Receivers should be able to find more than enough satellites outside the area of this anomaly at any given time. Navigation shouldn't be affected.
It has zero direct impact on us down here. It's another question that satellites and spacecrafts passing through it are affected, which i already mentioned, but this is the case since there's space travel or we are sending stuff to space. Aircrafts don't go that high. This 200 km altitude - where the anomaly is the closest to the surface of Earth - is 20 times the height, where aircrafts usually fly.
This is an anomaly of the inner Van Allen belt, which is known since the late fifties. There are two of these belts most of the time, sometimes there are more. They aren't constant either, it's not really surprising that this anomaly is changing too. They say, probably it has something to do with the pole reversal, which is a slow-moving thing, think hundreds of thousands of years.
The only new information in these articles, that the SAA seems to be splitting. Other than this it's just another thing the media is hyping up for no good reason.
