What GPS are you using? We're optimized for the uBlox or the new Mediateks with the 1.9 firmware.
And one of the standard quads (3DR frame, 850 motors)? We're getting rock-solid loiter with the default settings on standard frames.
Anything else unusual or non-standard about your setup? Are you using sonar? (you shouldn't be)
No sonar. It was rock solid before the update. Didnt change anything.
i have the same problem. i have 3rd party Gps but blue led is solid on. and sonar
I'm getting the same thing. "Figity" lotier and a drop as soon as I engage it. I think the drop might be some rough edges in the programming. I'm new to the arducopter and quads, but I attribute it to my bad mounting job of the Ardupilot. I was impatient and ziptied the board to the frame on top of some foam. It flew mostly fine but my Z accelerometer values were not good. I'm guessing that since 2.91 the accelerometer on the Z axis is used for alt-hold, and perhaps loiter modes. Before that I'm thinking that we could get away with a sub optimal mounting of the board, but not anymore. I haven't been able to test my theory because I tore down my machine to rebuild the mount, and I have only installed the latest version. I don't know off hand what a good value is for your Z accel data, but you might try logging it and trying to mitigate some of the vibration. That would be a good thing to do anyway. Check out the vibration section of the wiki. You might also try to turn down your rate "P" in loiter mode, so it's not as sensitive. I suppose it would be nice to be able to opt out of using the accelerometer data to assist in alt-hold, but I presume that would add more code to an already brimming CPU and end up masking physical problems which should be addressed anyway. FYI - I have a Ublox GPS, RCTimer clone, built on a DJI style 450 frame if that matters. Hopefully I will have it back in the air soon, and I will report back my findings.
I had this same issues using an older MTK gps not on 1.9 firmware. I switched to my ublock and it was back to rock solid. I also could not tune the MTK gps to a better loiter.
I'll try updating the MTK gps to 1.9 to see if it works better.