Geomagnetism/satellite-based trajectory correction projectile rolling angle measurement model and its error analysis

The rolling angle of trajectory correction projectile is an important original reliability parameter for the correction of trajectories. In this paper, we explore the trajectory correction projectile rolling angle detection system model based on the multibody system dynamics, geomagnetism detection technology and satellite navigation technology, under the assumption of an ideal working status. In order to project the geomagnetic vector onto the projectile cross sectional area, coordinate conversions among the geomagnetic coordinate system, the projectile body coordinate system, and the projectile axis coordinate system are conducted accordingly. Using the pitching angle and deflection angle calculated by satellite navigation data and the geomagnetic data detected by the geomagnetic sensor, we set up the initial values of the mathematical model. The projectile rolling angle is then calculated based on the algorithm of trajectory correction projectile real time rolling angle. Furthermore, the errors produced during the system working process are analyzed. It seems that the swing angle which caused by the projectile's initial disturbances will lead to rolling angle error. We have further analyzed the trajectory correction projectile rolling angle error under different fire condition in Nanjing, and simulated the mathematical models using Matlab. The simulation results show that the Geomagnetism/Satellite-based trajectory correction projectile rolling angle measurement model is feasible and valuable.