I don’t think that Iris does has a barometer or other altitude-sensing device, apart from the GPS unit. I know that GPS can approximate altitude, but not very accurately. So how is Iris able to land so nicely in Land or RTL flight modes?

I can’t get my computer to talk to Mission Planner. I plug my ArduCopter into a LiPo, turn on the transmitter (a Spektrum DX8, which is bound to the ArduCopter), then connect a USB cable to the ArduCopter. When I open Mission Planner the only…