6. Conclusions

Because of complex entry environment and particular dynamic characteristics, such as strong nonlinear and large flight envelope, LQR with weighting matrices constructed by traditional Bryson principle was not suitable for HSV profile-following in reentry reference trajectory guidance. On the basis of Bryson principle, this chapter proposed time-varying matrices constructed by current flight states. The capability of HSV tracking nominal profile using LQR with time-varying weighting matrices was significantly improved. From simulations, it could be clearly shown that the LQR designed by presented method was more robust than traditional way to different initial deviations and disturbances in the process of reentry flight.
