Application of two rapid transfer alignment methods in aerial guided weapons

The equivalence of two common rapid transfer alignment (RTA) models (ψ model and ψ_m model) is analyzed and proved. Based on this, the 11-vector ψ and ψ_m RTA models are built for aerial guided weapon by taking into account the MEMS-IMU's low precision and poor stability. Compared with the traditional 15-vector RTA model, the new model's computational complexity is reduced by 60%. Meanwhile, in order to improve the design flexibility and robustness of the RTA filter, a new filter design idea is proposed, which is a dual filter working in parallel, including one installation angle estimation filter and one gyroscope bias estimation filter. Also, a Kalman filter parameter's designing method for the RTA is put forward, which can effectively inhibit the device error's influence and environmental interference through isolating each channel's bandwidth. The results of flight tests demonstrate the effectiveness of the method. Furthermore, the new algorithm only takes less than 30 s to converge, which is better than the old one at optimizing efficiency. And the precision of transfer precision is increased by approximately 40%, which solves the problem of the low-precision MEMS-IMU in aerial guided weapons.