What is IMU?

There are apparently two Gimbal Operation Modes;   Follow Mode, and FPV Mode.  But, when you get ready to fly and check the Aircraft Status, there is a box with this designation "FPV Mode/Follow Mode".  How do you select one or the other?

Hello and good day wgray105. Thank you for the inquiry IMU, or Inertial Measurement Unit, is an electronic device that measures and reports an object's specific force, angular velocity and attitude using data from an accelerometer, gyroscope, thermometer, and barometer of the drone. The difference between Follow Mode and FPV Mode is that the image transmission screen will tilt when the left sticks are pushed to the left or right in FPV Mode while the image transmission screen will not in Follow Mode. Follow Mode tries to use the gimbal to keep the horizon level while flying. FPV Mode allows the camera to tilt while flying. I hope this helps. Thank you.

DJI Stephen Posted at 1-18 08:30
Hello and good day wgray105. Thank you for the inquiry IMU, or Inertial Measurement Unit, is an electronic device that measures and reports an object's specific force, angular velocity and attitude using data from an accelerometer, gyroscope, thermometer, and barometer of the drone. The difference between Follow Mode and FPV Mode is that the image transmission screen will tilt when the left sticks are pushed to the left or right in FPV Mode while the image transmission screen will not in Follow Mode. Follow Mode tries to use the gimbal to keep the horizon level while flying. FPV Mode allows the camera to tilt while flying. I hope this helps. Thank you.

Thanks for the info.  But, I haven't figured out how to switch between Follow Mode and FPV Mode.

IMU "Inertial measurement unit" .

As far as I see it, IMU calibration on a level surface updates a table of values the flight controller software uses as a reference for a level stationary hover. From there the craft responds predictably to flight commands.  It also likely measures any sensor noise and thermal drift so that these technical imperfections are accounted for when using IMU sensor data in flight. - this is likely why there must be no vibrations during the calibration process.


Bad IMU calibration could cause drift and attitude issues as the flight controller fights to hold the craft in what it thinks is the correct attitude as opposed to the correct physical attitude.


The IMU usually has 2 types of sensors – angle and acceleration and in turn 3 sensors of each type measuring in the X,Y and Z axis. These sensors can, through vibration, aging, impact etc, drift in their response over time and thus an IMU calibration will establish a new reference for the IMU’s level/stationary state that the flight controller can work with to restore stable flight.


Think of calibration as the bringing back into line the measured craft attitude with the true physical craft attitude.


As to how often an IMU calibration is needed, Refer to your manual ; certainly after any impact or if there are suspicions the craft can’t hover in a level attitude in a windless environment.

wgray105 Posted at 1-18 10:27
Thanks for the info.  But, I haven't figured out how to switch between Follow Mode and FPV Mode.

You set the modes in the Gimbal prefs -- here's what it looks like in the iOS version of Go 4:

Ex Machina Posted at 1-18 12:14
You set the modes in the Gimbal prefs -- here's what it looks like in the iOS version of Go 4:
https://youtu.be/UJ5l4DOCNpw

Thanks Ex Machina.  Here's what my screen looks like (hope you can see the picture).  I don't see any way to choose between Follow Mode and FPV Mode.

wgray105 Posted at 1-18 14:49
[view_image]

Thanks Ex Machina.  Here's what my screen looks like (hope you can see the picture).  I don't see any way to choose between Follow Mode and FPV Mode.

Is this an Android screen?

Normally, at least on iOS, the status screen isn't interactive except for updating software or compass settings. What does your Gimbal prefs screen look like?

Ex Machina Posted at 1-18 19:47
Is this an Android screen?

Normally, at least on iOS, the status screen isn't interactive except for updating software or compass settings. What does your Gimbal prefs screen look like?

Yes, this is Android.  And, I finally found the Gimbal prefs screen.  I'm sure you've noticed that I'm new at this.  Anyway, finally got there.  Thanks for your help.

wgray105 Posted at 1-18 21:18
Yes, this is Android.  And, I finally found the Gimbal prefs screen.  I'm sure you've noticed that I'm new at this.  Anyway, finally got there.  Thanks for your help.

A long time ago I was taught there are no stupid questions, just stupid answers so ask away

wgray105 Posted at 1-18 21:18
Yes, this is Android.  And, I finally found the Gimbal prefs screen.  I'm sure you've noticed that I'm new at this.  Anyway, finally got there.  Thanks for your help.

Awesome, glad you got it sorted!

I've been flying my Air for a few months now and I didn't even know this was an option.  Thanks for the "stupid" question!  I learned something because of it!