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An Explicit Closed-Loop Guidance for Launch Vehicles

Vittal, Vijay R and Bhat, Seetharama M (1991) An Explicit Closed-Loop Guidance for Launch Vehicles. In: Acta Astronautica, 25 (3). pp. 119-129.

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An explicit, near optimal, closed-loop steering logic common to both, 2- and 3-dimensional launch trajectories is presented. This scheme uses a single steering angle in a canted plane, which can then be resolved as pitch and yaw angles in any inertial frame. New, exact formulations for integrating the steering thrust acceleration are presented along with the existing series approximation. Using Enke's method, two uniform gravity vectors are evaluated to account for the actual effects of inverse square gravitational force field in the propagation of position and velocity vectors, during the future guided trajectory. An iterative differential corrector to solve for the guidance parameters that decide the steering angles and thrust cut-off is discussed. Also, means of overcoming the difficulties faced by the closed-loop guidance logic close to injection is presented. Simulations are conducted for a typical launch mission. The computational load for the onboard computer are estimated in order to explore the feasibility of realizing this guidance logic. Simulation study of the effects of computational delay is also presented.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to Elsevier.
Department/Centre: Division of Mechanical Sciences > Aerospace Engineering(Formerly Aeronautical Engineering)
Depositing User: Obaiah B
Date Deposited: 02 Nov 2006
Last Modified: 19 Sep 2010 04:31
URI: http://eprints.iisc.ac.in/id/eprint/8551

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