Do military training groups scramble GPS signals?

This fall we saw a bunch of Air Force SERE instructors setting up camp in a mountain range they haven't used before. For decades the have used the forest near the Pend Oreille river in WA state, but were up on the Kettle Crest during the last week of hunting season.

As I was heading cross country up a hill, probably about 5 miles from their camp, the GPS on my iPhone went crazy. First the compass pointed south, then froze, then started spinning faster than you could see, then it stopped and spun the other direction super fast. Then returned to normal.

Made me wonder if the SERE guys were using some sort of scrambler.

Using Gaia gps program.

By the way, the drivers we met from the Air Force were terrible. Afraid to get within 4 feet of the down hill shoulder. We had to put our driver side tires in the ditch with the passenger side way up hill to get around them when we met them on the little forest service roads.

Odd, compass in the iPhone should be unaffected by GPS shenanigans, as it has a chip that can detect magnetic north.

It was the compass arrow on the GPS program

Don’t be so fast as to say electronic signals can’t screw up an old fashioned magnetic compass. We used to sail with friends on Chesapeak Bay. We would regularly include a stop in Annapolis. Just as you round the point of the Naval Academy and turn to sail into the harbor you pass 3 ULF antennas. They are reputed to be part of the Navy’s secret comma system with submerged “Boomers” and other subs.


As you reach the vicinity of the point/ antenna, the magnetic compass , mounted on the steering stanchion, would go nuts . It spun like a top. It happened every time , over a number of years, albeit the ULF system was locally understood to have then been on standby mode , to be used only in an emergency failure of new primary systems in other locations.

Yeah, was saying GPS and compass functionality (in phones it's related to motion sensors) are not related.

Strong local magnetic fields can easily swamp Earth magnetic field.