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This version (21 Jul 2021 13:48) was approved by Chas Frick.The Previously approved version (21 Jul 2021 01:21) is available.
This version (21 Jul 2021 13:48) was approved by Chas Frick.The Previously approved version (21 Jul 2021 01:21) is available.This is an old revision of the document!
Table of Contents
ADI MEMS IMUs Glossary: Performance Characteristics, Measurement Setups and Applications
This page is intended to introduce and discuss common characteristics of MEMS IMUs, how to measure those performance metrics and finally some applications where those metrics matter.
Bias Repeatability
Measured in °/hour.
Bias Error
Offset error in MEMs output on a particular axis. Fixed error typically. Measured in °/hour.
Sensitivity Error
An error in the gain of the response. Non-uniformity that affects measurement output.
Allan Variance (AVAR)
A plot of noise versus averaging time.
In-run Bias Stability (IRBS)
This can be thought of as the sensor resolution in an “ideal case.” It is also found as the minimum of the AVAR plot.
Angular Random Walk (ARW)
Applies to gyroscopes. It is the “close-in” (small τ) on the AVAR curve and is noise that comes from the quantization process. Taken at Τ = 1 second.
(Angular) Rate Random Walk (ARRW)
Applies to gyroscopes and is the “far out” (large Τ) on the Allan Variance (AVAR) curve. This quantity represents long-term stability of the sensor measurement.
Velocity Random Walk (VRW)
Similar to the angular random walk (ARW) for gyroscopes. Noise from quantization of the axes.
Noise Density
Similar to amplifier noise density. RMS noise per unit of BW. Can be approximated with the formula: ND ≅ ARW/60* √2
Linear Acceleration Effect (Linear-g)
Measured in degrees/sec/g.
Vibration Rectification Error (VRE)
Measured in degrees/sec/g².
Cross-Axis Sensitivity
Unintended effect where rotation/acceleration from one axis is detected on another axis
Linear-g Rejection (Linear-g Sensitivity)
Unintended effect where linear acceleration is detected as rotation
resources/eval/user-guides/inertial-mems/imu-overview.1626823425.txt.gz · Last modified: 21 Jul 2021 01:23 by Chas Frick