High Performance MEMS Inertial Measurement Units (MEMS IMUs)

What is IMU (Inertial Measurement Unit)?

• Inertial measurement unit (IMU) is a device that measures the three-axis attitude angle and acceleration of an object. Generally, IMUs include a three-axis gyroscope and a three-axis accelerometer, and some IMUs also include a three-axis magnetometer. IMU has been widely used in fields of mobile phones, VR, aviation and aerospace.

• IMUs usually include gyroscopes, accelerometers, and sometimes magnetometers and barometers.

• An accelerometer is a sensor that measures a specific force. It provides acceleration across the x, y, and z axes within its local frame.

A gyroscope is a sensor that measures angular velocity around the x, y and z axes within its local frame. Generally, the measurements are integrated to derive the angle itself.

• A magnetometer is a sensor that measures the Earth's magnetic field and provides heading (a compass is one such device). If it is included in an IMU, we usually describe it as a "9-axis IMU".

• A barometer is a sensor that measures air pressure and provides altitude information.

How do IMUs work?

The working principle of IMUs is based on Newton’s laws of mechanics, by measuring the acceleration of the object in the inertial reference system, integrating it over time, and transforming it into the navigation coordinate system, the speed, yaw angle and position and other information in the navigation coordinate system can be obtained.

Therefore, the inertial measurement unit (IMU) is a strapdown inertial navigation system. The system consists of three acceleration sensors and three angular velocity sensors (gyros). The accelerometer is used to sense the acceleration component relative to the vertical line of the ground, and the speed sensor is used to sense angle information.

IMU consumer applications

According to different application scenarios and accuracy requirements, the gyroscopic components required for inertial navigation can be divided into strategic, navigation, tactical and commercial levels (consumer level):

1. Strategic application scenarios focus on the aerospace and navigation fields;

2. Navigation grade application scenarios are mostly various types of missile weapons;

3. Tactical grade application scenarios include ground weapons and aircraft;

4. Commercial grade application scenarios are for civilian use.