Hi guys, I thought I'd start a new thread to discuss whether anyone has experienced issues keeping the horizon level on their MOVI while flying. We all agree that it's easy to tune up a MOVI for use on the ground, but in the air the MOVI can be much more difficult to get right. Let's imagine the Alta is accelerating from Point A to Point B in a straight line, no change in altitude. The question is, how does the MOVI know which direction is straight up when it is accelerating in the horizontal plane? What the IMU reads is a mixture of acceleration due to gravity and the straight line acceleration from Point A to Point B. Without the GPS the MOVI would always think "up" is the vector addition of gravity and the MOVI acceleration vector. The MOVI software does a calculation using the IMU acceleration data and the GPS data to calculate which way is "up" for the MOVI by doing a vector subtraction (I assume). Depending on the amount of satellites the MOVI is locked onto, the acceleration readings from the GPS may not be very accurate. When the acceleration reading from the GPS are not accurate, the horizon will not be level when performing medium to fast acceleration movements with the MOVI. This is why the MOVI horizon tends to lean into the direction that the drone accelerates. Now I ask... why does the MOVI GPS module get placed directly under the ALTA where it is less than ideal for gaining good GPS reception? Food for thought....
Justin what type of 'flight'. My understanding is that the sensor pucks are doing all of the sensing, not the IMU. And they know when they are inverted. This would be a good question to the support@freeflysystems.com site. Unless someone from Freefly happens to see this post then the rest of us would be speculating since the secret sauce is just that, secret.
Justin: There are several threads that have raised this issue. The conclusion is that the Maxtenna GPS antenna improves things but, I'm thinking it might improve things even better to reposition the antenna to a place where it has a better sky view using an antenna extension cable and clamp. I've been meaning to try this -- I could have sworn that someone else did actually do this, but I cannot find the thread. I seem to recall that the gimbal control unit needs a lock on at least six satellites (with more being better). If the GPS signal is too weak, I think it's disregarded and therefore your vector analysis is absolutely correct. If only Einstein had not discovered that gravity and acceleration are equivalent... sigh. Andy. ---------- Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. The Ground Is The Limit™ ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert
Hi everyone I mounted the Maxtenna mounted using a longer coax SMA cable I made up (thanks Andy!). Our MOVI 10 now locks onto 10-12 satellites more consistently and the camera horizon is much better when I fly with more pace and acceleration.