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In (order to improve the navigation accuracy of launch vehicle in high dynamic, large airspace and high-speed flight conditions, a low-cost integrated navigation system based on GNSS/SINS in launch inertial coordinate system is proposed. In these flight conditions, influence of time synchronization on navigation accuracy is not negligible and it's difficult to obtain high-precision time synchronization information. Therefore, a novel algorithm to improve the time synchronization accuracy by using interpolation method is designed. Digital simulation and vehicle experiment illustrate that the position error is less than 5m, and velocity error is less than 0.2m/s. Thus, this GNSS/SINS integrated navigation algorithm can effectively improve navigation accuracy of launch vehicle.

When the three-loop autopilot parameters designed by linear systems are used on the actual nonlinear system, the actual flight control performance is often inconsistent with the design specifications. Therefore it is necessary to construct a simulation environment close to the actual flight conditions to perform further performance tests on the designed autopilot. The propose of this paper is to give a simulation method of autopilot performance test based on aerodynamic environment which uses the ballistic feature points to construct the simulation environment and determine the initial flight conditions. The matlab software is used to solve the ballistic equation. Combining with the non-linear constraints such as angle of attack and rudder deflection angle, the attitude stabilization process and overload tracking performance of missile under the action of autopilot are analyzed to evaluate the control performance of autopilot. Finally, by comparing the simulation results between aerodynamic and static environments, it is shown that this method can not only get the overload command adjustment time closer to the actual flight, but also get the system stability margin which varies with the angle of attack, so as to analyze the stability changes in the process of attitude adjustment. The difference between the practical application effect and design index of autopilot from two aspects of parameter design and non-linear constraints at specific angle of attack is explained by this paper, thus providing a new and effective method for theoretical design and control performance test of autopilot.