"I am in Canada. Currently the temperature is about -10˚C. It works well. The battery itself can produce heat during flight. A high discharge rate battery is recommend to lower the voltage drop. Also you can wrap the battery with some warm clothes."
"Like Armin said, PX4 code is more suitable for your demand. APM code is transferred from the old AVR based Arduino code. Actually I am using APM code because my old code is for APM 2.6. And it is easy to transfer to pixhawk hardware if I continue…"
"You should caution that the log rate is not the same with the actual calculate rate. A complimentary filter can't perform well with only 10 Hz. It should at least be 100 Hz"