An Accurate Guidance Algorithm for Implementation Onboard Satellite Launch Vehicles


Department of Electronical Engineering,Sharif University of Technology


An algorithm for guiding a launch vehicle carrying a small satellite to a sun synchronous
LEO is presented. Before the launch, a nominal path and the corresponding nominal control law for
the entire journey are computed. For each sampling instant during the guided
ight, a linear equation
approximately relating the di erences between the actual and nominal values is considered, and a Least-
Squares formula using data from on-line state measurements is applied to compute the actual control.
The coecient matrices of the Least-Squares formula can be determined by o -line computations. The
method enjoys simplicity of implementation by onboard computers, as well as robust accuracy against
strong winds and uncertainties in thrust magnitude.