Abstract: A new full order detection filter for a class of time-invariable systems is proposed. It obtains a detection filter for the original system by augmenting the original system and designing a new one. This filter can asymptotically detect m (can be increased to n) faults that occur simultaneously with the initial state estimations error. The relation between the detection threshold, designing parameters and the performance of the filter is analysed. The rules for the choice of the parameters and threshold in the design procedure are also given. The simulation result indicates that this detection filter has good detection capability.

Key words: fault diagnosis, filter, residual signal, decouple