Rotating Projectile Attitude Measurement Based On Full Accelerometers

With the booming trend of militarization in the world today,the guided projectile with higher precision and low cost has become the research focus.It is the key that precise attitude measurement technology will improve the accuracy of guided projectile.The traditional attitude measurement is mainly accomplished by accelerometers and gyroscopes,however,the gyroscopes tend to be damaged during the guided projectile launch so that it can’t measure attitude when the guided projectile has large acceleration.Therefore,as for the problems in the traditional method,the use of accelerometers to measure the attitude of a guided projectile is a better approach.With the rapid development of accelerometer manufacturing process,accelerometers have the advantages of low cost,low energy consumption,high precision and strong resistance to overload.The attitude measurement technology of the rotating projectile based on full accelerometers is studied in the background.Firstly,the air trajectory model is built,and the theoretical reference inertial data are calculated.Based on installation configurations of nine-accelerometer and twelve-accelerometer,a variety of methods for calculating the angular velocity of the projectile using the output of the full accelerometers are deduced.By simulation,it is clear that the integral method and logarithm method are used to solve the projectile angular velocity with high precision,and the twelve-accelerometer installation configuration is more suitable for the rotating attitude measurement system than the nine-accelerometer installation configuration.Secondly,as for the problem of positional installation error of f ull accelerometers,a novel twelve-accelerometer installation configuration is proposed to reduce the effect of positional installation error on solving angular velocity,and the corresponding error formulas are deduced.Comparing the traditional twelveaccelerometer configuration with the improved twelve-accelerometer configuration,it can be concluded that when the location mounting error of the accelerometer is the same,the improved configuration can improve the solution precision of the projectile’s angular velocity.Finally,considering the problem that the error of the attitude angle of the projectile by the fourth-order Runge-Kutta algorithm and the rotation vector algorithm based traditional inertial navigation will accumulate over time,the method of combining Geomagnetism and full accelerometers to measure the attitude of the projectile is studied.After analysis and simulation,this method effectively suppresses the divergence of the solution error of the attitude,and improves the precision of the attitude to some extent.