Research On Calibration And Initial Alignment Technology Of Strapdown Inertial Navigation

With the improvement of the inertial navigation system. The technologies of marine strap-down inertial navigation system develops rapidly. According to practical requirements of marine strap-down navigation system, this research which is based on lab's strap-down inertial navigation system developed by ourselves mainly focuses on the research of the calibration technology and initial alignment technology ,which can be summarized as follows:1 .The definition of the common reference frames and signs of strap-down inertial navigation system are researched. Then it summarizes the basic principle of strap-down inertial navigation system. It's main error sources of are analyzed. Besides, the error equations and the theory of the Kalman are given .2. The principle of discreet calibration method is discussed. We construct error models of inertial meters. On the basis of these models, we can get the relationship with inertial error and navigation error. Then,an experiment about discreet calibration on turntable is carried out with the detailed steps. The analysis of the effects of discreet calibration method on the SINS.Because of the multiple fallacies of discreet calibration, a new calibration method--the systematic calibration is presented.3. The analysis of the traditional systematic calibration, then, pointing out the localization which is based on traditional systematic calibration. On the base of this analysis,the new systematic calibration plan is advanced which separates the gyroscope from accelerometer and builds different error models between gyroscope and accelerometer. It designs the filter respectively. Then, an experiment about systematic calibration on turntable is carried out with the detailed calibration path. Kalman filter is used to estimate the calibration error by utilizing the three-axis turntable's velocity and attitude error. Based on the property of Kalman filter, the systematic calibration method is designed in the paper.4. The coarse alignment of the SINS is introduced,with analytic coarse alignment and horizon leveling plus azimuth estimation coarse alignment , and inertial frame coarse alignment. Based on the reference vectors of coarse alignment selected in the inertial frame,this dissertation studies the error analysis of the inertial mooring alignment. The analytical expressions relating gyroscope drift and accelerometer bias to misalignments are derived.Finally, Kalman filter alignment method in disturbing condition is studied.