Effect of direction error on the miss distance of rolling missiles with x-rudder

Based on the analysis of periodic equivalent control force of rolling missiles with x-rudder, the guidance loop model with direction error is established and the relationship between direction error and miss distance is analyzed. Results show that the miss distance is zero or a constant or infinite, and it is always zero when the real parts of system matrix eigenvalues decided by direction error are both positive values in an ideal system, in which all the lags are neglected. However, the miss distance gradually increases with the increase of the direction error and its variation is small when direction error is not more than 5° in the system, in which seeker lag and missile body lag are considered.