After replacing the broken boom from yesterday's failure and learning that the barometer onboard the APM is sufficient for autonomous landing I set out to test autonomous takeoff and landing today. I set the sonar so I could enable and disable it with a switch. I disabled the sonar while in autonomous mode. I also moved the sonar inboard to the center underneath the copter. I added a power filter circuit to filter the power going into the sonar to reduce electrical noise. I also created a funky foam shield around the sonar to reduce prop wash and prop audio noise interfering with the sonar. After the successful auto takeoff and landing test. I fly it around a bit manually and enabled the sonar to see if it is now agreeing with the barometer. I will review the flight logs to make sure the sonar is working correctly before I try using it again. I ended up with two totally successful completely autonomous flights today same route twice, 8 waypoints, autonomous takeoff, and landing