Hallo, I want to install a sonar on my quadcopter, if I do that wil the altitude hold alway use the sonar sensor input or wil it switch to GPS wen the sonar get no reading, example if the quadcopter is on 300 feet altitude and the sonar can not…

Hi, I try to find a alternative for xtreambee board.I use a Ardupilot mega with a IMU Shield/OilPan Rev-H V1.0.My question is, can i use this board http://garden.seeedstudio.com/index.php?title=UartSBee#Windowswith this…