Research on Projectile-borne GFIMU Configuration Based on Pure Accelerometers
In order to improve the attitude measurement accuracy of artillery projectile to carry out long-range precision strike,and considering the low-cost,miniaturization and high overload require-ments,a projectile-borne gyro-free inertial measurement unit(GFIMU)based on pure accelerometers was studied.According to the mechanism of the arm effect caused by the eccentricity of the accelero-meter,GFIMU with 9/12-channel accelerometers were analyzed and selected.Taking the output error as the optimization objective,the position of the GFIMUwas optimized based on the constrained multi-objective particle swarm algorithm.Then,the nonlinear state space equation of the quadratic terms of angular acceleration and angular velocity was established,and the noise correlation between the process equation and the measurement equation was corrected.An EKF estimation method for angular velocity under noise-related conditions was designed.Finally,a typical trajectory model with a typical MEMS acceleration sensor noise was established.The simulation results show that the GFIMU is theoretically effective and can meet the accuracy requirements for short-time projectile attitude calculation.