Research Of Composite Attitude Measurement Methods Based On Magnetic/Low Cost MEMS Inertial Device

In recent years, the INS navigation has been widely used in fields such as aviation,weapon equip, cars and communications, because the INS navigation has a lot ofadvantages, for instance, the high precision, the low cost, the nicer self-determinationand so on. But the MEMS parts of an apparatus used in INS are usually inexact, andthe error of the INS is accumulated along with the time goes, so it is difficult to workfor a long time for the INS system. The geomagnetism exists in all of the earth surfaceand the nearby space. It is a vector contains size and direction, and it can be used innavigation for its stability and disciplinarian. A investigation of attitude measuringbased on the geomagnetism and the low cost MEMS organ is introduced.Firstly, the types of the geomagnetism sensors used in geomagnetism detect andthe inertial organs used in INS are introduced. The error elements of these sensors areanalyzed and the primary error models are established. The error coefficients are alsocomputed and the equalizing results are tested by a serious of experiments. Experimentresults show the exactness of the equalizing method.Secondly, a friendly software is empolderd to show the outputs of thegeomagnetism sensors and the INS sensors. The geomagnetism theory and factor areintroduced. We also established each reference frame to describe the attitude of thecarrier and derivated the attitude measuring method based on geomagnetism theory.We can’t get all of the3angles by geomagnetism. The attitude measuringsemi-physical experiments based on geomagnetism and a new method are carried out.Thirdly, the strapdown inertial navigation theory and quaternion method areintroduced and analyzed. Attitude measuring method based on geomagnetism/accelero-meters and geomagnetism/gyro are studied. The former method is to get the pitch androll of the body by geomagnetism sensor and accelerometers, and the latter is to get theattitude array by quaternion and differential equation. The method to solve differentialequation is Runge-Kutta method. Lastly, some experiments are carried out aimed at the research of attitudemeasuring. The results are accurate as2°what shows the method is correct andfeasible.