RoboticsLesson 3 of 5 in the course Sensors and perception

IMU Measurements, Inertial Navigation, and Sensor Error

5 flashcards · 5 quiz questions · 5 match pairs · 4 fill-in sentences · English

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Summary

An inertial measurement unit (IMU) measures motion and, in some configurations, helps estimate a body's orientation. This lesson introduces the sensors inside an IMU, the measurements they provide, and where IMUs are used.

An inertial measurement unit (IMU) is an electronic device that reports a body's specific force and angular rate. Some IMUs also estimate or report orientation. In practical terms, an IMU senses how a device accelerates and how quickly it rotates.

All flashcards

What does an inertial measurement unit measure?
It measures specific force and angular rate; some units also estimate orientation.
What does an accelerometer measure?
Linear acceleration along one or more axes.
What does a gyroscope measure?
Angular rate, or how quickly an object rotates.
What is an IMMU?
An inertial measurement unit that includes a magnetometer, commonly used as a heading reference.
What is drift in inertial navigation?
Increasing inaccuracy in motion estimates as sensor errors accumulate during integration.

Quiz questions

  1. What does an attitude and heading reference system (AHRS) generally estimate from IMU measurements?Answer: Vehicle attitude and heading.
  2. In strap-down inertial navigation, what is done with acceleration after it is transformed into an inertial reference frame?Answer: It is integrated to estimate velocity and then position.
  3. What is dead reckoning?Answer: Estimating motion from a known starting state and measured changes.
  4. What is one trade-off of mounting an IMU on shock absorbers?Answer: They reduce mechanical disturbances but increase size and mass.
  5. How can an external position reference such as GPS help an inertial navigation system?Answer: It can correct accumulated errors in the navigation estimate.

Based on the Wikipedia article Inertial measurement unit, licensed CC BY-SA 4.0. Adapted into a summary, flashcards and quizzes.

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