I need some serious input and advice. I am on my 4th flight this evening and all was going well until the unthinkable happened. I calibrated aircraft due to moving approx 20 miles from my last flight. Here are these steps that I followed. Placed the aircraft with battery facing me. Ensured S1 and S2 were in the up position. I then powered the aircraft, transmitter then Wifi. I then enabled my wifi on my my phone and the aircraft connected to phantom wifi. The aircraft flight control lights in the rear went from yellow flashing to immediate slow green flashing. I then proceed to conduct calibration. I toggle the S1 5 times and the flight control lights changed to steady yellow. I complete my first 360 degree rotation of the calibration and the flight control lights changed to immediate steady green, I then invert the aircraft in nose down position and then complete the second calibration rotation, flight control light changed to a "very short steady yellow" and then to an instant slow flashing green. My GPS meter was at 8. I start engines and wait one minute for more possible satellites and then lift off. I flew the aircraft out and back to me. I then send her up to an altitude of maybe 20' and away approx 15'. I placed her into a hover while I adjusted camera tilt and then all the sudden the aircraft took of on a hard bank to the right and straight toward me with no input from transmitter. I tried to climb and turn with no response. She continued hard right and headed straight for me. I am 6'7 so in a hale marry attempt to leap and grab her skids as she came overhead. Fortunately I grabbed her landing gear and immediately pull left stick down and hold until they stopped. after I gathered my composer I checked all controls and noticed that the GPS signal was bouncing from 4-7 intermittently. please know that i have read this manual from cover to cover enough times I can nearly repeat it verbatim. I watched every tutorial youtube has long before ordering this unit. I downloaded and read the manual several time before ordering this unit. I have very strict pre-flight check that I complete twice before I even turn on the unit. I am at a loss. What did I do wrong? Also on the second nose down clockwise rotation what color should the flight control lights be? Should it go to steady yellow for a second and then to the slow green? ( I Know that slow green indicates GPS mode) Am I missing something? I would truly appreciate any input or advice, I have had this unit for only 1 week and it does this.