Cooperative Incremental Mid-Course Guidance Law Under Uncontrollable Speed With Prescribed Performance and Enhanced Robustness

To solve the multi-missile formation problem in the mid-course guidance phase under uncontrollable speed, a cooperative mid-course guidance law is proposed in this paper via incorporating the leader-follower formation strategy with an incremental nonlinear dynamic inversion-prescribed performance control (INDI-PPC) scheme. As a design baseline, the formation model is constructed based on the leader-follower tracking discipline under the inertial system. To deal with the uncontrollable speed issue encountered in practice, the cooperative guidance formation model is transferred via the coordinate system transformation theory. Then, the second-order derivative of the missile's position and the guidance command at the previous sampling moment is fully mined to obtain an INDI-based cooperative incremental mid-course guidance (INDI-CMG) law for large guidance gain avoidance and robust enhancement. To further achieve cooperative guidance with prescribed performance, the INDI-CMG law is extended to an INDI-prescribed performance CMG (INDI-PPCMG) law. The finite time convergence analysis for the proposed two kinds of INDI guidance laws is presented, and it shows that the INDI-PPCMG law has a smaller gain than that of the INDI-CMG law. It differs from the current cooperative mid-course guidance design in that the problem is handled by an incremental approach with a prescribed performance guarantee such that smaller gains are obtained for robustness enhancement and prescribed performance is ensured for guidance accuracy improvement. It is preferable for practical implementation since the uncontrollable speed is considered and the derived guidance form has a simple structure. Extensive simulation results verify that the proposed method is capable of maintaining the multi-missile formation under uncontrolled speed in the mid-course phase even in the presence of uncertainties.