SINS & AHRS¶
SINS (Strapdown Inertial Navigation System)¶
Some basic processes for SINS based on MARG (Magnetic, Angular Rate, and Gravity) are implemented, including electromagnetic compass calibration, an AHRS (attitude and heading reference system) that use an extended Kalman filter (EKF), and trace tracking. Loosely coupling sensor fusion by using the minimum squared error (MSE) method is also implemented.
AHRS¶
Attitude and Heading Reference System
An AHRS consists of sensors on three axes that provide attitude information for aircraft, including roll, pitch and yaw. These are sometimes referred to as MARG (Magnetic, Angular Rate, and Gravity) sensors and consist of either solid-state or microelectromechanical systems (MEMS) gyroscopes, accelerometers and magnetometers.
The key difference between an IMU and an AHRS is the addition of an on-board processing system in an AHRS, which provides attitude and heading information.
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Sensor Fusion Algorithms: There are a variety of sensor fusion algorithms out there, but the two most common in small embedded systems are the Mahony and Madgwick filters.
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psiphi75/ahrs: AHRS (Attitude Heading Reference Systems) calculation for JavaScript
IMU Attitude Calculation¶
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IMU Data Fusing: Complementary, Kalman, and Mahony Filter
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cggos/imu_tools: ROS tools for IMU devices
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IMU-sensor-fusion-with-linear-Kalman-filter (mathworks): Reads IMU sensor (acceleration and velocity) wirelessly from the IOS app 'Sensor Stream' to a Simulink model and filters an orientation angle in degrees using a linear Kalman filter.
Dead Reckoning¶
In navigation, dead reckoning is the process of calculating one's current position by using a previously determined position, or fix, and advancing that position based upon known or estimated speeds over elapsed time and course.