Abstract: An adaptive parameter estimation method during PEG（powered explicit guidance） is proposed to solve the difference between true parameters of lunar ascent body and guidance parameters saved in guidance computer. Some parameters that have an influence on PEG are transferred to two parameters vex and τ, including mass, mass flow rate, specific impulse, force and so on. Based on accelerometer output, the parameters can be estimated. Finally the necessary and validity of the method are proved via comparing the PEG simulation results respectively with adaptive estimated parameters and the original parameters.

Key words: parameters, adaptive estimation, lunar powered ascent phase, PEG