To improve the navigation and positioning precision of the rocket guidance platform, is one of the important research fields of rocket test technology. For a certain type of rocket guidance platform, an indirect output revising navigation algorithm is proposed, which is based on multiple sensors of Inertial Navigation System(INS) combined with Global Positioning System(GPS). In the algorithm, Kalman Filtering(KF) is utilized for optimum estimate of the systematic error, and the estimation results are adopted for correct inertial navigation calculating and sensor output. Simulation results show that, in the case that GPS works effectively and the rocket dynamics perform stably, the integrated navigation algorithm has obvious inhibitory effect on INS error accumulation over time.