Abstract: A differential game guidance law based on game theory is developed for the underwater interceptor in order to improve the ability to intercept an unknown target in collaborative defense. A tripartite maneuvering game model is established, in which the homing constraint information can be obtained using the line-of-sight command. The method of solving the terminal problem by the adjoint mathematics is used to get the zero effort miss distance of the differential strategy by taking terminal miss distance and control energy as the performance indexes, which can be applied to arbitrary order control situation for tripartite strategies. The receding horizon control is used to predict the guidance law parameters in real time. The differential game strategy is simple to implement in practical applications under the conditions of homing. The performance of the guidance law is analyzed, and the effects of intercepting the targets by using different guidance laws are compared. The simulated results show that the differential game guidance law is robust adaptability and stability, which is not restricted by the maneuvering forms of targets under the condition of same constraints, and is of better trajectory characteristics.

Key words: ordnance science and technology, differential guidance law, underwater interceptor, cooperative engagement, zero effort miss distance