Research On SINS Initial Alignment Error On Moving Base

Now most of high-precision inertial navigation systems are rotating inertial navigationsystems, they can compensate the error automatically by the rotating modulation technique.On the basis of no need to improve the precision of inertial devices, rotating inertialnavigation system can keep high precision in a long time, and make significant costreductions. Rotating inertial navigation system has became a hotspot of current research athome and abroad, but the research of rotating inertial navigation system is still in its infancyin domestic. The rotation modulation principle and translocation programs are in-depthstudied, but the initial alignment/measurement drift technology is less researched. Initialalignment/measurement drift technology has become one of the key technologies whichrestricted the development of inertial navigation system in domestic. In this paper, taking theFOG-SINS developed by our laboratory for study object, research the initial alignmenttechnology of rotating inertial navigation system in depth, the main work specified as follows:Firstly, the principle of strapdown inertial navigation system and the rotating inertialnavigation system are compared and analyzed, and then a definition of the commoncoordinate system and inertial navigation system algorithms theory is given. The error sourcesof the SINS are analyzed; the error model of the fiber-optic gyroscopes and accelerometers isset up, the features of rotating SINS initial alignment is analyzed.Secondly, the theory of traditional analytic coarse alignment is analyzed. According tothe solution of transformation matrix in the alignment process based on inertial coordinatesystem and the environmental characteristics under the moving status, digital filter for inertialcoarse alignment methods is used, and a filter for engineering is designed, then the simulationand analysis is finished.Thirdly, the FOG-SINS algorithm of compass alignment is given, the effects of staticerrors on the alignment accuracy are analyzed, and the steady-state error expression is given.On this basis, against the environmental characteristics under the moving status, the analysisof swing movement for compass alignment is completed, and swing motion compensationmethod to reduce the impact of swing motion on the compass alignment is proposed. Then,simulation experiments are done.Finally, the high-dimensional error equation of dual-axis rotating SINS is derived, then, a16-dimensional Kalman filter state equations and three commonly used measurementequations is established. To improve the estimation accuracy and shorten the estimated time, the dual-axis rotation scheme of initial alignment phase by using PWCS observability analysismethod is designed. Then, the simulation and experimental analysis are completed...