Online Analytical Guidance for a Solid-Fuel Launch Vehicle in Boost Phase Based on Generalized Zero Effort Miss

An online analytical guidance for a solid-fuel launch vehicle in boost phase based on generalized zero effort miss (GZEM) is proposed. In order to adapt to complex missions, the concept of the zero effort miss (ZEM), which is widely used in missile guidance, is extended to cover all terminal state deviations. We call it the GZEM. In order to predict the GZEM onboard, analytical solutions for zero-effort trajectory in boost phase are derived using a perturbation method. Compared with the numerical trajectory simulations, the computing efficiency of the analytical solutions is improved by nearly 100 times, which can meet the needs of onboard applications. In addition, by solving the optimal control problem using the indirect method, an online analytical guidance based on the analytical solutions is derived successfully, which can adapt to the constraint that the solid propellant motors cannot be throttled and shut down once they are ignited. Simulation results verify that the proposed online analytical guidance has the advantages of high accuracy and strong robustness.