This is getting less complex as we go along, but it is starting to make sence.
The attitude and heading reference system looks just like the
inertial measurement unit (IMU). Very confusing till I read this.
"An attitude and heading reference system (AHRS) consists of sensors on three axes that provide
attitude information for aircraft, including roll,
pitch and
yaw. These are sometimes referred to as MARG (Magnetic, Angular Rate, and Gravity)
[1] sensors and consist of either solid-state or
microelectromechanical systems (MEMS)
gyroscopes,
accelerometers and
magnetometers. They are designed to replace traditional mechanical
gyroscopic flight instruments.
The key difference between an
inertial measurement unit (IMU) and an AHRS is the addition of an on-board processing system in an AHRS, which provides attitude and heading information. Versus an IMU which just delivers sensor data to an additional device that computes attitude and heading. With sensor fusion, drift from the gyroscopes integration is compensated for by reference vectors, namely gravity, and the earth magnetic field.
[2] This results in a drift-free orientation, making an AHRS a more cost effective solution than conventional high-grade IMUs (
Inertial Measurement Units) that only integrate gyroscopes and rely on a very high bias stability of the gyroscopes. In addition to attitude determination an AHRS may also form part of an
inertial navigation system."
Attitude and heading reference system - Wikipedia
So rather than a IMU the more sophistical drones have the AHRS which has the additional "on-board processing system... " and "an
inertial navigation system." But they are still referred to as IMU by DJI and other drone manufacturers.
Now the question is does the Tello have a on-board AHRS? It seems as the
Mavic 2 and Phantom 4 series definitely have it.
On the Tello channel
"Camera in the middle feeds the optical flow system.
Big holes beside it are IR transmitter and receiver, used for accurate short range distance to ground.
Inside there is a barometer but naturally this can't be too accurate."
volate!lo
In a way it does not matter for the updated video I need to do, bearing in mind it is intended as an introduction for your Joe who does not have an in depth technical background.
It will be difficult enough to explain the middle camera the two black and red either side of it, and a simplified IMU.
The Tello definitely has at least a IMU, it says so in the documentation and in the app in cog, more, 3 dots, IMU status. That must be one small IMU in an 80 gram drone.
So in order to make it accessible and engaging to Joe, a simplified explanation is bound to be technically insufficient but necessary if you get my meaning. Excuse my copy and pasting and to the TelloPilot.
Do I have this right?
