1. A method for performing a fault estimation based on a plurality of residuals of a plurality of detected signals, comprising: determining an operating regime based on a plurality of parameters; extracting predetermined noise standard deviations of said residuals corresponding to said operating regime and scaling said residuals; calculating a magnitude of a measurement vector of said scaled residuals and comparing said magnitude to a decision threshold value; extracting a mean direction and a fault level mapping for each of a plurality of fault types, based on said operating regime; calculating a projection of said measurement vector onto said mean direction of each of said plurality of fault types; determining a fault type based on a maximum projection of said measurement vector onto said mean direction of each of said plurality of fault types; and mapping said projection to a continuous-valued fault level using a lookup table.