Magnetometer Digital Signal Processing Technology For Measurement Of Projectile Rolling Angle

Trajectory correction as a key technology to improve the accuracy of conventional ammunition strikes is an important direction for the development of ammunition.Accurate real-time projectile roll angle measurement is an important guarantee for ballistic correction.The use of magnetic sensors to measure the roll angle of a projectile has the advantages of high reliability and non-accumulation of errors.It has been widely used in ballistic correction missiles.The measurement accuracy of the missile-borne magnetic sensor determines the measurement accuracy of the roll angle of the missile.Compared with magnetoresistive sensors,digital fluxgate magnetometers have the advantages of high sensitivity,zero bias,and stable operation.Therefore,the fluxgate magnetometer is selected as the magnetic sensor for the missile load angle measurement system and the missile load is established.The fluxgate magnetometer measures the angle system and simulates the signal processing process of the fluxgate magnetometer and the mounting error of the two-axis fluxgate sensor.This paper first analyzes the basic performance of various types of magnetic sensors,selects the fluxgate sensor as the magnetic sensor of the ballast angle measurement system;according to the basic principle of the fluxgate sensor,it establishes the sensing signal of the dual-core fluxgate sensor.The mathematical model determines the linear relationship between the fluxgate sensing signal and the measured geomagnetic field.The principle of measuring the angle of the two-axis magnetometer is introduced,and the installation error of the two-axis magnetometer is theoretically analyzed.Secondly,the digital signal processing process of fluxgate magnetometer was introduced,including A/D conversion of fluxgate sensing signal,digital waveform “ gate ” processing,digital band-pass filtering,digital detection and integral amplification processing,and magnetic flux.The digital signal processing model of the door magnetometer was simulated and analyzed;the installation error of the dual-axis fluxgate magnetometer was numerically simulated,and the measurement error of the roll angle when the installation error of the dual-axis fluxgate magnetometer was installed was analyzed..Finally,the hardware circuit system of the missile fluxgate magnetometer was analyzed with the DSP digital signal processor as the core,and the non-orthogonal errors of the dual-axis fluxgate magnetometer were compensated and calibrated.The simulation results show that the fluxgate digital signal processing system eliminates the measurement errors caused by the inconsistency of the upper and lower cores,suppresses the noise of the fluxgate induced signal,and improves the output precision of the fluxgate magnetometer;The missile fluxgate magnetometer angle measurement system has no zero bias and does not require initial calibration.The accuracy of the angle measurement can meet the accuracy requirement of the roll angle measurement of the ballistic correction projectile.