Explore the connection and difference between AHRS and IMU Release date:2020-12-10   Browsing volume:373

The heading and attitude reference system includes a MEMS-based three-axis gyroscope, accelerometer and magnetometer. The difference between the heading and attitude reference system and the inertial measurement unit IMU is that the heading and attitude reference system (AHRS) includes an embedded attitude data calculation unit and heading information, and the inertial measurement unit (IMU) only provides sensor data, not accurate Reliable posture data function. At present, the commonly used heading and attitude reference system (AHRS) uses the multi-sensor data fusion to calculate the heading and attitude calculation unit as a Kalman filter.

The heading and attitude reference system includes the following features: high-precision 360-degree omni-directional position and attitude output, the use of Euler angles will have a universal lock and cannot rotate in all directions; efficient data fusion algorithm fast dynamic response and long-term stability , No accumulation error); the output mode is divided into three-dimensional full attitude data (quaternion/Euler angle/rotation matrix/raw data) and three-dimensional acceleration/three-dimensional angular velocity/three-dimensional geomagnetic field strength.

AHRS originally originated from aircraft-related technologies, but in recent years, as the cost of cost components continues to decrease, it has also been widely used in motor vehicles and unmanned aerial vehicles, industrial equipment, cameras and antenna gimbals, ground and underwater equipment, Virtual reality, life motion science analysis and other products that require three-dimensional posture measurement.


The inertial measurement unit is a device that measures the orientation and attitude of the moving carrier through the accelerometer and gyroscope. Its functions and devices are similar to those of AHRS, but the biggest difference is that the heading and attitude reference system includes an embedded attitude data solving unit As with heading information, the inertial measurement unit only provides sensor data and does not have the function of providing accurate and reliable attitude data. The lack of a part of the function is not necessarily a bad place, because the lack of a part of the unit makes its cost lower and can be used in more places to measure the orientation of various equipment.

The inertial measurement unit is composed of three accelerometers and three gyroscopes. Three are used to measure the orientation of the three axes. These accelerometers and gyroscopes are input along the three axes of space, that is, three are perpendicular to each other. The direction axis. Through such a distributed design, it can move any line or angular motion of the moving carrier in space, but because the gyroscope measures the relative spatial position change, and the carrier to be measured needs the reference object of the system, so it needs to coordinate Transform, so you get the data you want to measure.

Inertial measurement units are mainly used in equipment that needs to control the orientation and attitude of moving objects, such as automobiles, robots, and missiles. Although it is currently used more on equipment such as aircraft, with the development and advancement of technology, more industrial equipment has begun to use it for position measurement. It is worth mentioning that now this technology is also beginning to experiment in agricultural operations, because the operation of machinery is prone to accidents during agricultural operations, and the use of inertial measurement units for real-time detection equipment can greatly reduce the possibility of accidents. Therefore, its application range is getting larger and larger.

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The inertial measurement unit eliminates errors mainly through various compensations and improving instrument reliability. The inertial measurement unit of Beiwei Sensing adopts MEMS accelerometer and gyroscope, and guarantees the measurement accuracy through algorithms. At the same time, the sealing design and strict production process ensure that the product can accurately measure the angular velocity, acceleration and attitude of the carrier in harsh environments. And other motion parameters. Through various compensations such as nonlinear compensation, quadrature compensation, temperature compensation and drift compensation, the error source can be greatly eliminated and the product accuracy level can be improved.

The inertial measurement unit is the basic unit of the inertial measurement system, but it can also act on the moving object alone to measure the position and attitude. Because of its small size, light weight, and high reliability, the inertial measurement unit will be used in more places, such as tactical weapon guidance, self-driving car safety protection, etc. Its development direction will also be smaller and smaller, and its precision taller and taller.

TAG: Inertial measurement unit


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