Research On The Geomagnetic And Inertial Attitude Measurement

In this paper,a geomagnetic inertial integrated attitude measurement structure is designed based on the missile body attitude measurement,and the characteristic is that only one gyroscope and three magnetoresistive sensors are used in this structure to meet the whole attitude measurement requirements of the conventional missile body.Furthermore,with the assist of magnetoresistive sensor,the dynamic range of fiber-optic gyroscope can be enlarged to meet the attitude measurement requirements of the rotating projectile.Besides the large range of application,the advantages of the structure designed by this paper also include simple construction,low cost,high accuracy and independence.Firstly,we introduce some methods of the missile body attitude measurement and the research status of geomagnetic navigation and geomagnetic inertial integrated attitude measurement,and explain the geomagnetic field basic theory.Then we write programs for the flight track generator to simulate two kinds of missile body motion tracks.At the same time,generating simulation signals of magnetoresistive sensors and gyroscope to data sources for the following simulation.Secondly,according to the output characteristics of the inertial device and geomagnetic attitude measurement mathematical model,a geomagnetic inertial combined attitude measurement structure is designed which consists of three magnetoresistive sensor and a fiber-optic gyroscope.For the combined structure,this paper gives two kinds of attitude measurement schemes which are suitable for the measurement of the attitude of the missile body and the attitude measurement of the rotating projectile respectively.Attitude calculation is derived,which is about the attitude of the missile body.And the calculation is used to calculate the motion of the missile body and the precision is relatively high.Thirdly,this paper analyzes the flight characteristics of the rolling projectile.There are two roll angle speed measuring methods based on the magnetic resistance sensor for the high speeded roll angle of the rolling projectile.Then the method is proposed which can expand the range of fiber optic gyroscope using magnetic resistance sensor.It also introduces the attitude calculating algorithm of the rolling projectile and analyzes magnetic resistance sensor blind measuring area.Finally,a algorithm of wavelet threshold filtering is chosen to eliminate the noise of the signal according to the output characteristics of the noise of magnetoresistive sensor and the fiber-optic gyroscope.Select Haar,db5,coif5 wavelet on the sensor output signal filtering under different decomposition scales,and the results show that wavelet decomposition of filtering effect is better with the increase of the number of decomposition layers,under the same decomposition layer,the best wavelet filtering is coif5.