Estimation Method Of Projectile Roll Angle Based On Geomagnetic/Gyroscopic Information

Due to its excellent anti-high overload performance,geomagnetic navigation has become a very widely used navigation method for artillery guided munitions in the current military field,which can effectively avoid the error accumulation problem of traditional inertial navigation.However,in the application of the geomagnetic attitude measurement method in the attitude measurement of the missile,the change of the magnetic field environment of the missile body under the influence of the launch high-overload environment will lead to inaccurate pre-calibrated parameters,resulting in a large error in the attitude angle solution.Besides,the traditional attitude solution method based on geomagnetic information needs a known attitude angle for calculation.Usually,one of the attitude angles is assumed according to the ballistic kinematics model.There is a problem that the assumed value does not match the actual angle value,resulting in other attitude angles calculation results have large errors.Aiming at the problem that the ground-calibration parameters are inaccurate and the magnetic field value measurement is inaccurate due to the change of the magnetic field environment after launching,this paper proposes an on-line correction technology for the projectile interference magnetic field.The magnetic vector information of the system is sine-like fitting,the kinematics model of the magnetic field signal is established,the difference calibration is designed for the axial signal,and an online correction method based on high-pass filtering is designed for the radial signal.It has been verified by the simulation test and semi-physical test that the online correction method using real-time filtering can effectively improve the measurement accuracy of the magnetic field value and the roll angle solution accuracy.Compared with the accuracy before correction,accuracy improved by about an order of magnitude.Aiming at the problem that the geomagnetic attitude measurement system needs a known attitude angle to solve the problem,a roll angle estimation method with complementary geomagnetic and gyro information is proposed.In order to solve the attitude angle assumption problem of geomagnetic information,a gyro assist magnetometer algorithm is designed in combination with gyro information,and on this basis,the gradient descent solution method is simplified according to the ballistic model,the correction coefficient of the PI system is added,and the magnetic field information is used to calculate the attitude angle offset.The offset error and estimation error existing in the gyro angular rate are effectively compensated,and the simultaneous high-precision estimation of the three attitude angles is realized,improved the accuracy of roll angle greatly,meets the precision requirements of the guided munitions on the roll angle measurement data.In this paper,by designing an on-line compensation method for the interfering magnetic field on the missile,the problem of inaccurate measurement of the magnetic field value caused by the interfering magnetic field of the missile is solved,the correction of the magnetic field information before data correction is realized,and a more accurate magnetic field information measurement method is provided for data fusion.Then,based on the gyro assist magnetometer method,a geomagnetic/gyro complementary attitude measurement algorithm is proposed,which effectively solves the problem of error accumulation in pure gyro calculation and the deviation of the assumed value of attitude angle of pure geomagnetic information.Through relevant simulation and semi-physical experiments,the accuracy and effectiveness of the designed algorithm are verified,which can meet the roll angle accuracy requirements of artillery guided munitions,and provide a new attitude measurement scheme for the low-cost guidance and intelligent development of traditional munitions.