Okay, this seriously can't be normal. Pre-flight check IMU accelerometer and gyroscope bias excellent (very low) Compass interference excellent (very low) GPS locked with 10 satellites At a height of 391 ft directly overhead, and only 1:20 into my flight, these errors start popping up: Compass Error. Exit P-GPS Mode IMU heading error. Please restart the aircraft. Weak GPS signal. Positional accuracy may be compromised. Please fly with caution. Abnormal compass function or GPS signal detected. Aircraft switched to ATTI mode. By the time I was able to regain control, it had drifted off course by a quarter mile with no line of sight. I was able to navigate back by finding familiar landmarks in the live feed and quickly landed, but again, this seems highly unusual. I have had countless other flights in the same area with no issues, this just seems to happen from time to time.