Focusing on the research of unknown input observer of good performance to deal with the problem of control system's sensors fault
a method using a full-order state observer to estimate the disturbance matrix of turboshaft engine system model was proposed based on the analysis of relationship between the disturbance matrix reflecting modeling uncertainty and the accuracy of states observed by UIO. This method contributed to an accurate disturbance matrix so that the results of UIO had no combination of modeling uncertainty when the operating state of turboshaft was fixed. Furthermore
this method was developed to meet the requirements of variable operating states of the engine so that the modeling uncertainty had no influence on the design of UIO in this situation. Finally
some simulations were made to verify the proposed methods
which contribute to obtain a better matrix to ensure that the observed output residual of UIO is less than 2.