Precision terminal guidance law for missiles using direct force control systems

In missiles using direct force control systems, a high precision robust guidance law with low side jet consuming is required. Those in open literatures are either less precise, or too complex to apply. A variable structure guidance law is researched for an anti-ballistic missile using direct force control system. It adapts to discontinuous control and acquires high precision with no more information needed. Based on a nonlinear model, it ensures the final high precision. A suitable slide function avoids unnecessary requirements of information. The result established by the approaching law is simple to compute overall. Tree-dimension trajectory simulation results are given. The results show that variable structure guidance law acquires higher precision than proportional navigation, especially in case of intercepting maneuvering targets. They also show that variable structure guidance law gets more straight terminal trajectory and lower side jet consuming than proportional navigation, because it corrects the error of guidance earlier. All the guidance laws designed take large interception angle compared with reverse trajectory interception, so the base may be disengaged and less preparing time is required.