This paper presents a three-layer general process model for unanticipated state recognition in a telescope drive system, consisting of an anticipated fault diagnosis layer, an unanticipated normal state isolation layer, and an unanticipated fault state recognition layer.

It is proposed for the first time to subdivide the unanticipated state into an unanticipated normal state and an unanticipated fault state in this paper, and to study their theories separately. Unanticipated normal state isolation rules based on angle deviation and amplitude deviation are established, as are unanticipated fault state recognition rules based on angle deviation and deviation contribution factor. Finally, normal operation data of the Antarctic Survey Telescope (AST3-3) combined with fault implantation was used to verify the validity of the model. The results show that the method can effectively carry out isolation of the unanticipated normal state and identification of the unanticipated fault state.