Estimation of Circular Error Probability of Strapped Down Inertial Navigation System by Propagation of Error Covariance Matrix

Abstract

This paper provides an error model of the strapped down inertial navigation system in the state space format. A method to estimate the circular error probability is presented using time propagation of error covariance matrix. Numerical results have been obtained for a typical flight trajectory. Sensitivity studies have also been conducted for variation of sensor noise covariances and initial state uncertainty. This methodology seems to work in all the practical cases considered so far. Software has been tested for both the local vertical frame and the inertial frame. The covariance propagation technique provides accurate estimation of dispersions of position at impact. This in turn enables to estimate the circular error probability (CEP) very accurately.