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For a higher accuracy of projectiles, a novel trajectory correction fuze is proposed. In this design, the sensor and actuator were reduced to achieve a balance between performance and affordability. Following introduction of the fuze concept, the flight model was presented and the crossrange and downrange components of trajectory response under control were investigated. The relationship between the inertial coordinate system and the detector coordinate system was studied so that the imager feedback could be used to derive the actual miss distance. The deployment time of canards and roll angle of the forward fuze were derived and used as the inputs of the control system in this strategy. Example closed-loop simulations were implemented to verify the effectiveness of the strategy. The results illustrate that the accuracy increase is evident and the proposed correction concept is applicable for terminal correction of mortars.

The balance of stability and maneuverability is the foundation of the trajectory correction projectile. For the terminal correction projectile without an attitude feedback loop, a larger control force is expected which may cause an instability. This paper proposes a novel method to derive instability boundaries for the control force magnitude. No additional coordinate system is needed in this method. By introducing the concept of angular compensation matrix, the exterior ballistic linearized equations considering control force are established. The necessary prerequisite for a stable flight under control is given by the Routh stability criterion. The instability boundaries for the control force magnitude are derived. The results of example flights are 13.5% more accurate compared with that in relevant research. Numerical simulations demonstrate that if the control force magnitude lies in the unstable scope derived in this paper, the projectile loses its stability. Furthermore, the effects of the projectile pitch, velocity, and roll rate on flight stability during correction are investigated using the proposed instability boundaries.

Successful terminal correction without an attitude feedback loop is a challenging task. Much innovative effort is required to achieve a balance between performance and affordability. This paper presents a unique trajectory correction fuze with a reduced number of sensors and actuators. A rapidly calculable analytical dynamic response model for the terminal control force is derived, in which the oscillation part is emphasized because of the limited time-to-go. The accuracy and effectiveness of the analytical model are verified by comparison with 6DOF nonlinear simulations. The influences of the velocity, rotation rate, and pitch on the dynamic response during terminal correction are subsequently investigated using the analytical model. To enable a deep investigation of stability under terminal control with a trajectory correction fuze, the Routh stability criterion is considered to define the necessary prerequisites for stable flight. The validity of the derived instability boundaries is demonstrated through numerical simulations.