"Thanks Scott, I'll try this again in an open field. Multipathing sounds like it might be the answer (although my iPhone is rock solid under similar conditions...argh).
I had a spectacular tree-house-deck collision due to faulty voltage calibration…"
In the test below the drone never moved from its grounded positionu. 3dr Ublox standard GPS.The picture shows a solid satcount = 8, gpshdop = 1.2 and the drone apparently flying all over the place. The track varies by about 35 meters--way beyond…