Abstract:

To weaken the influence of constant bias of inertial elements on navigation precision of strapdown inertial navigation systems (SINS)， a single-axis rotation modulation scheme is put forward and the systematic error function is established， thereby modulating the constant drifts of gyros and the zero error of accelerometers into periodically varying quantities. The systematic observability is improved by changing the strapdown matrix in the inertial navigation error model. The degree of observability for SINS is computed in the context of resting and rotating inertial measurement units respectively using the spectral condition number theory， and accurate alignment of the rotating SINS is achieved by the introduction of Kalman filter. Simulation results show that the presented alignment method could eliminate the impact of constant drifts of gyros and the zero errors of accelerometers on the systematic alignment precision， and greatly improve the alignment precision.