Research On Transfer Alignment Methods For Single-axial Rotary Strap-down Inertial Navigation System

With the continued development of the rotation modulation technology, Single-axis rotary Strap-down Inertial Navigation System (SINS) are applied to the actual system increasingly due to its high accuracy. As a moving base alignment method, transfer alignment is widely used in initial alignment of weapons and equipment which are working in dynamic environments, such as shipboard, airborne, vehicle and so on. In this paper, transfer alignment method of that main INS is single-axial rotary SINS is researched for typical engineering applications.Firstly, the theory of single-axis rotary SINS and single-axis rotary error automatic compensation were analyzed. And then three kinds of single-axis rotation schemes were brought forward based on the theory. As the modulation result of three schemes was calculated, the error model and the precision of ingle-axis rotary SINS were also discussed before summarizing the characteristics of three common transfer alignment schemes.Secondly, the filter model for velocity matching transfer alignment was presented. On one hand, the effects that the main INS rotating in different way which include of the Single-axis one-position rotary, the Single-axis two-position rotary and the Single-axis four-position rotary on the velocity matching transfer alignment were analyzed, on the other hand, the effects that caused by different rotary angle rate and period on the velocity error and velocity matching transfer alignment when a single-axial rotary INS take as a main INS were discussed. Moreover, the carrier moving in which way would also have an effect on error modulation results and the observability of the velocity matching transfer alignment. The results of simulation say that it is faster and more accurate for alignment with line moving than angle moving.Thirdly, as a basis of attitude matching method the attitude that should be produced by the single-axial rotary INS is simulated, and then the filter model is given in details which make it possible to analysis the effect of Single-axis rotary rate on attitude matching transfer alignment. Account for the main error source of Single-axis rotary system, we study the attitude error caused by angle measurement error of turntable, and simulations about different result of attitude matching transfer alignment with different angle measurement error are given. In addition to, how the moving ways of carrier influence the attitude matching transfer alignment are analyzed in depth. Form the simulations we know that it can finish the alignment well with swing but unable with line moving.Finally, angle rate of the single-axis rotary inertial system as a main INS used in the angle rate matching transfer alignment was simulated and how it effect the angle rate matching transfer alignment was analyzed. To study the turntable error works on angle rate error, some simulations have been done and focus on the influence of angle rate about horizontal and azimuth direction on angle rate transfer alignment. Then the observability of the rate matching transfer alignment when the carrier was moving is analyzed and the moving state effects on the alignment result as it's for attitude matching.