Decoupled Scalar Approach for Aircraft Angular Motion Estimation Using a Gyro-Free Inertial Measurement Unit

In-flight aircraft angular motion estimation based on an all-accelerometers inertial measurement unit (IMU) is investigated in this study. The relative acceleration equation as the representative of a rigid-body kinematics is manipulated to present the state and measurement equations of the aircraft dynamics. A decoupled scalar form (DSF) of the system equations, as a free-singularity problem, is derived. Mathematical modeling and simulation of an aircraft dynamics, equipped with an all-accelerometers IMU, are employed to prepare measurement data. Taking into account the modeling of accelerometer error, the measurement data have been simulated as a real condition. Three extended Kalman filters (EKFs) are used in parallel to estimate aircraft angular motion. Performance of the estimation algorithm is assessed by Monte Carlo analysis. As a result, the presented decoupled scalar approach using a gyro-free IMU (GF-IMU) provides an uncorrelated estimate of the in-flight aircraft motion components.