Guidance scheme for near-earth low-thrust orbit transfers using blended locally optimal laws

A simple autonomous guidance scheme is proposed for near-earth low-thrust orbit transfer problem, based on blending the locally optimal laws. First, the locally optimal control laws are derived for each modified equinoctial orbital element. Then, the locally optimal control laws are blended by taking considerations of the efficiency of any attempt to alter an orbital element and the deficits of each element from the final target value, so that only a few guidance parameters are required to be designed. Moreover, a new switch function is defined for solving the optimal fuel transfer problem. Finally, a hybrid optimization algorithm combining genetic algorithm with sequence quadratic programming is utilized to design the optimal guidance parameters. Different from classical methods, the proposed guidance algorithm is a closed-loop fashion, which can be easily implemented on board the spacecraft, and needs not to update the guidance parameters in the transfer process. Taking low-thrust transfer from LEO to HEO as an example, the minimum-time and fuel-optimal guidance problems are solved by the proposed algorithm, respectively. The effectiveness of the proposed algorithm is validated by comparing with the classical algorithms.