Ballistic missile impact point accuracy based on hybrid inertial navigation system configuration optimization

To improve the impact point accuracy of ballistic missiles, this paper presents an efficient configuration optimization method for a hybrid Inertial Navigation System (INS). A rapid error computation model for the hybrid INS is developed based on the perturbation method, reducing the computation time of the Circular Error Probable (CEP) to seconds-level and enabling fast pre-launch configuration optimization. Furthermore, the influence of the sensitive-axis orientation of inertial components on navigation accuracy is investigated. Using CEP as the performance metric and representing configuration parameters with quaternions, an optimization model is established that avoids computational singularities while fully covering the attitude space. Simulation and mechanistic analysis indicate that the proposed approach can improve missile impact accuracy by approximately 20%–30% without additional hardware cost or trajectory modification. For certain flight trajectories, this approach also achieves higher accuracy than static optimal configurations. This improvement primarily results from the effective suppression of residual installation errors in inertial components, thereby significantly enhancing navigation accuracy across different launch directions and validating the effectiveness and generality of the proposed method.