Trajectory Generator of SINS Based on Flight Mechanics and Control in Simulink

To carry out the hardware-in-the-loop (HWIL) simulation of a guided rocket, the mathematical models of the trajectory generator of a strapdown inertial navigation system (SINS) based on flight mechanics and control are discussed. The highly precise six-degree-of-freedom (6DoF) model in the launch-centered earth-fixed (LCEF) frame is introduced, and the typical guidance and control methods are given. The relationship between 6DoF model output and SINS input is presented. The specific force is generated by the thrust and aerodynamic force output by the control system that acted on the guided rocket. The angular rate is generated by the torque and aerodynamic moment output by the control system that act on the guided rocket. Using the Integrator block of the Simulink software, the specific force and angular rate are integrated with high sampling frequency. The velocity increment of an accelerometer and the angular rate increment of a gyroscope are obtained. Then the accelerometer pulse and gyroscope pulse are obtained. The simulation results show that the precision of the accelerometer pulse and gyroscope pulse satisfies requirements for the SINS performance in the HWIL simulation.