• International Journal of Aeronautical and Space Sciences
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• 제13권2호
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• pp.154-169
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• 2012

This paper presents a comprehensive review of spacecraft guidance algorithms for asteroid intercept and rendezvous missions. Classical proportional navigation (PN) guidance is reviewed first, followed by pulsed PN guidance, augmented PN guidance, predictive feedback guidance, Lambert guidance, and other guidance laws based on orbit perturbation theory. Optimal feedback guidance laws satisfying various terminal constraints are also discussed. Finally, the zero-effort-velocity (ZEV) error, analogous to the well-known zero-effort-miss (ZEM) distance, is introduced, leading to a generalized ZEM/ZEV guidance law. These various feedback guidance laws can be easily applied to real asteroid intercept and rendezvous missions. However, differing mission requirements and spacecraft capabilities will require continued research on terminal-phase guidance laws.

• International Journal of Aeronautical and Space Sciences
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• 제18권4호
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• pp.729-739
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• 2017

The objective of this study was to optimize minimum-energy impulsive spacecraft intercept using genetic algorithms. A mathematical model was established on two-body system based on f and g solution and universal variable to address spacecraft intercept problem for non-coplanar elliptical orbits. This nonlinear problem includes many local optima due to discontinuity and strong nonlinearity. In addition, since it does not provide a closed-form solution, it must be solved using a numerical method. Therefore, the initial guess is that a very sensitive factor is needed to obtain globally optimal values. Genetic algorithms are effective for solving these kinds of optimization problems due to inherent properties of random search algorithms. The main goal of this paper was to find minimum energy solution for orbit transfer problem. The numerical solution using initial values evaluated by the genetic algorithm matched with results of Hohmann transfer. Such optimal solution for unrestricted arbitrary elliptic orbits using universal variables provides flexibility to solve orbit transfer problems.

• 한국항공우주학회지
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• 제46권11호
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• pp.902-910
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• 2018

본 논문은 지구의 J2 섭동을 고려한 비공면 타원궤도에서의 우주비행체의 요격 문제를 다룬다. J2에 의한 영향은 지구를 돌고 있는 우주비행체 궤도를 변화시키는 주된 요인이 되며, 이를 해결하기 위해 실시간 요격 방법을 제안한다. 구형의 지구와 순간추력을 고려한 운동방정식을 기반으로 최적화 문제를 구성하고 수치적으로 얻어진 최적해를 인터셉터의 추진방향으로 설정한다. 위치 오차는 최적화 문제를 반복적으로 해결하고 인터셉터의 추진방향을 수정하는 방식으로 해결한다. 다양한 궤도를 상황을 고려하여 제안하는 방법을 검증한다.