Abstract:

Aiming at the problem of the midcourse trajectory generation and modification in the interception against hypersonic targets in near space, a novel optimal trajectory modification algorithm is designed. Firstly, the demand for trajectory generation and trajectory modification in the midcourse phase is analyzed. The first order necessary conditions for the nominal optimal trajectory are given based on the Pontryagin minimization theory. Secondly, the first order necessary conditions are further differentiated to second variation to acquire the control modifications. The difficulty of the costates deviations acquisition is solved by reversely integrating using the nominal trajectory information to get the expression with the terminal constraints modifications and the current states derivations. Finally, digital simulations under different scenarios are carried out to testify the effectiveness of the proposed algorithm and the results are compared with those given by the Gauss pseudospectral method (GPM). Simulations results show that the algorithm has the merits of high precision and efficiency than the GPM, which is preferable for the online realization.