For rockets can only do two degrees of freedom in angular motion in the preparation phase before the launch, causing some parameters are not significant deficiencies. In this paper, based on the context of transformation of the guided rockets, a calibration solution was made which joined the roll campaign in the preparation phase before the launch and the corresponding observability analysis method was proposed. First, a 21-dimensional error model was established. And the observability analysis method was used to analyze the observability of the error parameters, then a comparison of the three phases was made. Results show that multiple parameters become considerable because the roll motion and other parameters′ observability are also significantly improved. Finally, the singular value decomposition method was used to verify the calibration of the proposed programs and observability analysis method. Results show that almost all parameters′ singular values are greater than 1, fully embodies the effectiveness of the roll motion to the error parameter estimation and the feasibility of observability analysis.