An iterative guidance method based on yaw angle conditions

Abstract

The invention provides an iterative guidance method based on yaw angle conditions, the method comprising vector calculation under a launch inertia system and calculation of vector conversion under aguidance coordinate system, estimation of remaining flight time, calculation of first and second integrals of thrust term and gravitational term, solution of program angle coefficient and program angle conversion under two coordinate systems. This iterative guidance method can be used to solve the guidance problems at large yaw angles due to large initial deviations or other reasons. The guidancecommand is simple in structure and practical in engineering, which can enhance the adaptability of iterative guidance method and provide technical support for the future development of advanced launchtechnology in China, including vertical take-off and landing, self-adaptive orbiting and so on.

Description

technical field [0001] The invention belongs to the technical field of guidance and control, in particular to an iterative guidance method based on yaw angle conditions. Background technique [0002] The traditional iterative guidance method has been widely used in the orbital guidance of the vehicle due to its advantages of high guidance accuracy, strong task adaptability, simple flight software, and relatively low requirements for off-line element preparation. This method is derived from the optimal control theory, with the least fuel economy as the performance index, and the attitude angle command is calculated online according to the real-time state provided by the vehicle's own navigation system, that is, the optimal thrust vector direction of the fuel required to complete the flight mission, and finally guarantees Five of the six state constraints such as terminal speed and position at the time of shutdown are satisfied. This method has been applied in the "Saturn 5" ...

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Problems solved by technology

[0004] However, due to the large initial deviation or many other reasons (such as the guidance target of the VTVL reusable vehicle booster return segment rotating with the earth), it is often necessary to fly under the condition of a large heading angle in actual engineering. At this time, the traditional iterative guidance method The small yaw angle assumption used in the derivation process is no longer applicable, and the remaining working time estimated in real time is difficult to guarantee a convergence trend or even diverge, which will lead to the failure of the guidance task, so the adaptability of the traditional iterative guidance method is greatly reduced

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