Abstract
This paper proposed an analytical iterative guidance method with the desired instantaneous impact point constraint for solid rockets in “burn-coast-burn” trajectory mode. Solid rocket motors expect to remove the thrust termination mechanism to increase the structural strength and launch reliability, which induce new difficulties and challenges to the guidance problems. In terms of the “Hohmann transfer” principle, a pointing algorithm is deduced in depth to establish the theoretical relations among the ignition time, the required velocity vector, and the orbital element constraints and provides the analytical expression of the ignition time. Then, an analytic solution of the required velocity vector is derived based on orthogonal and nonorthogonal velocity vectors, and a complete guidance logic is used to solve the target orbit elements satisfying the desired instantaneous impact point. Finally, the application of the developed theoretical algorithm in this paper is conducted using a two-stage solid rocket. The proposed guidance method is verified by Monte Carlo simulations, and the testing results demonstrate the adaptability, strong robustness, and excellent performance for different desired impact point missions.
Highlights
Solid rockets without the thrust termination mechanism can be launched rapidly with high manoeuvrability and agility, fulfilling the longed-for requirement of responsive launching missions, which brings new difficulties and challenges to its guidance technology [1]
To improve the load-to-structure mass ratio and increase the strength of structure, the thrust termination mechanism is removed from solid rocket motors [5], which will cause the solid motors to shut off only by the fuel exhaustion instead of the main engine cut-off controlled by the guidance commands
In order to satisfy the instantaneous impact point constraints of solid rocket with coast arcs, this paper presents an analytical instantaneous impact point guidance method that combines the solution of ignition time and the iterative calculation of the target orbit
Summary
Solid rockets without the thrust termination mechanism can be launched rapidly with high manoeuvrability and agility, fulfilling the longed-for requirement of responsive launching missions, which brings new difficulties and challenges to its guidance technology [1]. References [19, 20] and [21] use the linear programming method to design an open-loop alternating attitude energy management algorithm (AEM) and spline energy management (SEM) guidance method, which further neutralizes the additional velocity component to strengthen the terminal constraints These classical methods have been reliably and widely applied to the current launch vehicles, there are some limitations of the above methods in the solid rocket with burn-coast-burn flight mode such as the improvement of mission requirements, especially under the characteristics of fast response mission, because the closed-loop guidance method does not have multiterminal constraint capability, and the iterative guidance method is only applicable to the propulsion process.
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