What is the difference between a 3-axis gyroscope, 3-axis accelerometer and 3-axis magnetometer? How do these sensors work? Why are all 3 used in some devices like smartphones, tablets, quadcopters etc.?
Electronic – What are the differences between a gyroscope, accelerometer and magnetometer
accelerometercompassgyroimusensor
Related Topic
- Electronic – Temperature compensation of LSM303DLHC accelerometer / magnetometer
- What are the limitations of IMU sensor devices
- Electronic – the difference between IMUs and other devices that have accelerometers and gyroscopes (smartphones, tablets, sensewear etc.)
- Electronic – Tilt compensation for yaw calculation from magnetometer and accelerometer
Best Answer
They are three sensors that are useful for determining position and orientation, but they measure different things.
The reason these sensors are combined is because they excel at different things. For example, for orientation, a magnetometer has poor accuracy for fast movement, but pretty much zero drift over time. An integrating scheme using gyros on the other hand reacts quickly and accurately to changes, but accumulates vast error over time. It also requires to start from a known orientation, as it only reacts to changes.
Combining the inputs to these sensors allows for quick and accurate position and orientation determination with a low amount of drift over time.
Together, these sensors are also referred to as an Inertial Measurement Unit, or IMU. You can find more information on the wikipedia page for this term. Note that the unit is not strictly speaking purely inertial when you add magnetometers, but this nomenclature is widely used.