Based On The Detection Of Three-dimensional Magnetic Projectile Attitude Angle Detection Technology

In order to improve the accuracy of conventional ammunition, trajectory correction came into being. How to obtain the projectile fling attitude is a key technology related to the hit accuracy. For the projectile flying attitude detection that based on 3-dimension geomagnetic detection, this paper does a research in mathematical model for attitude calculation, hardware and software design, experiment, and error compensation.Under the premise of ideal trajectory, a mathematical model for calculating the attitude based on geomagnetic vectors is established. The bilinear interpolation method is applied to calculate the initial geomagnetic vectors, which can decline the restores of setting system. Carry out the bilinear interpolation coefficient and errors of selected area.The hardware of attitude detection system is designed with 3-axis MR sensor and ARM microprocessor. To against the bridge offset MR sensor, a compensation method is given and a set/reset circuit is designed. As the sensor output signal can change in a large range, a variable-gain amplifier is designed. A moving-average filter is applied to deal with the sampled geomagnetic signals. Within program design for the attitude calculation, look-up table method is used in combination with the linear interpolation method to solve the problem about anti-trigonometric function.An external measurement and calibration system is designed, with a special 3-axis turntable. An analysis of the error existing in MR sensor when applied in the attitude detection system is done. Correction method is given for the system error. The magnetic deviation compensation method is given to deal with the soft and hard magnetism disturbance. With the circuit board of the attitude detection system, calibration experiment is carried out. Through Contrastive analysis of experimental data that before and after compensation in five pitch attitudes on the north (yaw angle = 0°), results show that after compensation the error is within±1°, which can meet the needs of trajectory correction projectile.