Online Calibration of Inertial Sensors for Range Correction of Spinning Projectiles

摘要

This Note shows the potential dispersion improvements that can be made by implementing a drag-altering fuze on a conventional 155 mm artillery round. As stated earlier this was achieved without GPS, using instead the fixed frequency emitter from the muzzle velocimeter to calibrate a single-axis accelerometer after the bias shift that is expected from the extreme shock load on gun-launched projectiles. This type of in-flight calibration represents an extension to the current practices in guided projectiles. Experimentally evaluating the accelerometers before and after gun launch has verified that the bias instability is not an issue when considering the short time frame in which the guidance sensors operate (less than 1 min). Contrary to what was expected, it is noteworthy that the reduced-order, 2×2 matrix method outperformed the full-state history method. A simple proportional-integral (PI) type controller is sufficient to meet the goal of 50% reduction in range error, though performance increases can probably be made by evaluating more involved guidance laws, especially focusing on the power required to maneuver the control surfaces versus the effect on the kinetic energy of the projectile. Additional exploration into the differences between the two machine learning methods is warranted as well as potential impacts on operational usage of the fuze/projectile (i.e., whether or not the different dispersion would be useful for illumination or smoke as opposed to conventional explosives).