  Error distribution analysis is an important assistant technology for the
research of SINS(Strapdown Inertial Navigation System). Error distribution
result can provide the contribution of different errors to final navigation
error, which is helpful for modifying and optimizing SINS. To realize
decomposing the navigation error into parts that caused by each error source,
the SINS error state space model is established and covariance matrix is
decomposed according to error sources. The proposed error distribution analysis
method based on 34-dimension SINS error model can quantitatively analyze the
contribution to the end navigation error of initial errors, IMU(Inertial
Measurement Unit) bias, IMU scale factor errors, mounting errors of gyroscopes
and accelerometers, and IMU stochastic errors. The simulations in static
condition and single axis rotation condition indict that the distribution
result of proposed analysis method accords with the law of error propagation.
After trajectory determined, the corresponding error distribution result will
be calculated with the proposed method. Compared with the Monte-Carlo method
and other method based on covariance matrix, the proposed method uses more
complete error model, considers the interaction effect of error sources and can
be easily realized with less computation.
