Methods for Determining the Initial State of a Projectile Equipped with Onboard Strapdown Sensors
Technical Report,04 Jun 2019,16 Aug 2019
Rose-Hulman Institute of Technology Terre Haute United States
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Projectile aerodynamics for long-range and indirect-fire shots may be characterized using onboard magnetometer, gyroscope, and accelerometer sensors. Previous researchers have developed ways to match projectile aerodynamic parameters to the collected measurements however, accurate reconstruction of the projectile trajectory was hindered by the ability to accurately estimate projectile initial states. In this work, we demonstrate the application of several models to better match the trajectory and sequentially update estimates of the initial projectile state. The final product is a set of algorithms that renders accurate initial-condition estimates that can then be merged with an existing high-fidelity ballistics code in order to provide accurate reconstruction of the projectile trajectory. Models for both 6- and 7-degree-of-freedom projectiles are demonstrated. The algorithms are exercised on actual and virtual data sets, and convergence to realistic initial conditions, parameters, and trajectories is reliable even in the presence of unmodeled sensor errors.