Sensing rotation, the IMU
1.[2p] A gyroscope is trusted for the fast part of attitude sensing because
A gyroscope is trusted for the fast part of attitude sensing because
The answer is: it reports rotation rate immediately, with little delay or sensitivity to vibration
The answer is: it reports rotation rate immediately, with little delay or sensitivity to vibration
The answer is: it reports rotation rate immediately, with little delay or sensitivity to vibration
2.[2p] An uncalibrated gyroscope has a bias of 0.3 degrees per second. If its rate is integrated to estimate angle while the craft sits still, how many degrees of error accumulate after 120 seconds?
An uncalibrated gyroscope has a bias of 0.3 degrees per second. If its rate is integrated to estimate angle while the craft sits still, how many degrees of error accumulate after 120 seconds?
3.[2p] An accelerometer can estimate tilt without drift because
An accelerometer can estimate tilt without drift because
The answer is: it reads the fixed direction of gravity directly, needing no integration
The answer is: it reads the fixed direction of gravity directly, needing no integration
The answer is: it reads the fixed direction of gravity directly, needing no integration
4.[2p] The accelerometer is unreliable for tilt during flight because
The accelerometer is unreliable for tilt during flight because
The answer is: it cannot separate gravity from the craft's own vibration and acceleration
The answer is: it cannot separate gravity from the craft's own vibration and acceleration
The answer is: it cannot separate gravity from the craft's own vibration and acceleration
5.[1p] A flight controller asks to sit still and level at power-up so it can measure and subtract each sensor's resting bias.
A flight controller asks to sit still and level at power-up so it can measure and subtract each sensor's resting bias.
The answer is: True
6.[2p] Filtering the raw IMU signals is a compromise because
Filtering the raw IMU signals is a compromise because
The answer is: more smoothing removes noise but adds delay, and delay in a fast control loop causes trouble
The answer is: more smoothing removes noise but adds delay, and delay in a fast control loop causes trouble
The answer is: more smoothing removes noise but adds delay, and delay in a fast control loop causes trouble
7.[3p] Match each sensor to its strength and its weakness.
Match each sensor to its strength and its weakness.
Gyroscope strength
Gyroscope weakness
Accelerometer strength
Accelerometer weakness
noisy and fooled by motion in flight
immediate, accurate rotation rate
drifts when integrated to an angle
drift-free sense of which way is down
Show the answer
Gyroscope strength: immediate, accurate rotation rate Gyroscope weakness: drifts when integrated to an angle Accelerometer strength: drift-free sense of which way is down Accelerometer weakness: noisy and fooled by motion in flight