Early this morning when practice the Go Home control at the lake side, I found there was a big circle surrounding the red PV2+ aircraft icon on my cell phone map. It limited my distance to the boundary of the circle which was 1000 ft radius. I had to set my waypoints within this circle. Actually, the max radius is 5249 ft as default, I didn't make any change. Why I got this circle radius restriction in the location ? It never happens before in my previous Ground station fly.