Analysis on launch-window extending capability of combined cycle power vehicle based on hp-adaptive pseudospectral method

In view that traditional launch vehicles has such defects as limited ballistic lateral adjustment ability and fixed launch window, etc., a horizontal taking-off / landing vehicle scheme with combined cycle power (CCP) is proposed. The transverse maneuverable ability of the combined cycle launch vehicle (CCLV) is of great benefit for launch window extending. The mathematical model of the CCP vehicle is derived, and the mapping relationship between the cross range and the launch window is established, so the extending ability of the CCLV can be achieved by optimization theory. In consideration of the complexity of the flight environment, the performance of the dynamic system is closely coupled with the flight state, and the flight trajectory of the vehicle is optimized by using hp adaptive pseudo-spectral method. This algorithm automatically determines the number and location of the newly increased nodes, and replaces the node increment by increasing the polynomial order. By this way, the unnecessary mesh refining is avoided, and the dimension of the constitutional nonlinear programming problem is reduced, so the initial values are easy to choose, and the solution speed is fast. Finally, the test results verify the feasibility of the proposed algorithm and the extending ability of the CCP vehicle launch window.