Terminology » RF Components » Accelerometer vs Gyroscope: Key Differences Explained

Accelerometer vs Gyroscope: Key Differences Explained

accelerometer gyroscope sensor motion measurement

This article compares Accelerometer and Gyroscope, highlighting their key differences.

Accelerometer

MEMS Accelerometer

  • Accelerometer sensors are available in one, two, or three-axis models.
  • They are used to detect the magnitude and direction of acceleration.
  • Applications: Three-axis versions are commonly used in smartphones, while two-axis versions are found in cars.
  • Highly sensitive accelerometer sensors can measure acceleration more easily compared to low-sensitivity ones.
  • An accelerometer can be used as a tilt sensor, but not all tilt sensors are used as accelerometers. For example, a mercury-based tilt sensor cannot provide a measurement of acceleration.
  • Accelerometers work based on Newton’s second law of motion (F = m*a), where ‘a’ is acceleration, ‘F’ is the applied force to the mass ‘m’ attached to the wall through a spring (with coefficient ‘k’).
  • The figure above depicts part of the internal structure of a MEMS accelerometer. It is similar to a spring-mass system.

Gyroscope

MEMS gyroscope-A tilt sensor

  • Definition: A Gyroscope is a device used for navigation and angular velocity measurement. A Gyroscope made using MEMS technology is known as a MEMS gyroscope.
  • MEMS gyroscopes use a very small vibrating mechanism to detect changes in orientation. Gyroscopes can measure the rotational velocity of one, two, or three-direction axes. A 3-axis accelerometer is sometimes used to implement a 3-axis gyroscope.
  • There are various types of gyroscopes, including mechanical gyroscopes, electronic gyroscopes, and MEMS gyroscopes.

Difference Between Accelerometer and Gyroscope

The following table summarizes the key differences between Accelerometers and Gyroscopes:

SpecificationsAccelerometerGyroscope
FunctionSenses linear movement, effective for tilt detection, but less precise for rotations.Measures all types of rotation, but not movement.
Signal to noise ratioLowerHigher
MeasurementIt can not measure rotation around its own axis of movement.It can measure angular velocity.

Conclusion

From the differences outlined above, we can conclude that accelerometers and gyroscopes have distinct functions. Accelerometers sense axis orientation, while gyroscopes sense angular orientation.

A combined solution of both accelerometer and gyroscope in a single device allows for both rotation and movement tracking. They are often used in conjunction with a magnetometer. This combined sensor system, consisting of an accelerometer, gyroscope, and magnetometer, is known as an IMU (Inertial Measurement Unit).

IMUs are used for complete motion control of aircraft, satellites, and more.