When your GPS is jumping, are you inside a large building such as big stores or manufacturing buildings? Mine jumps around at work inside the manufacturing building and sometimes inside the grocery store or other large buildings. It never seems to do this out side. On occasion I’ve had it jump down in my basement. I think its the result of only being picked up by one tower and it has to guess your distance and the bouncing is a second tower faintly picking you up and cutting out.
If you pull up google maps, it with show your jumping there also. I’ve jumped back and forth as much as a mile from my actual location, usually within a half mile. The points I jump back and forth to has changed over time to different spots but the general same area. I can’t figure it out. It’s random but get popped to the same points for weeks at a time and then changes to different points.
My Ipad wonders back and forth as much as 3-400 feet. When I go down to the river, it will wander even farther. There are spots where my Ipad GPS just completely goes out like GPS dead zones. I don’t think my Ipad GPS is very strong.