1. An apparatus for identifying a specific emitter in the presence of noise and/or interference, the apparatus comprising: a sensor configured to receive a portion of a radio frequency band and produce complex data, the complex data containing noise and one or more observations of a signal from at least one emitter including a particular emitter to be identified; an SINR enhancement unit configured to enhance the SINR of one or more unknown signals in the complex data; a reference signal generation unit configured to estimate a reference signal relating to the signal transmitted by the particular emitter; a pulse shaping filter estimation unit configured to estimate the pulse shaping filter coefficients used to produce the signal transmitted by the particular emitter; a feature dimension reduction unit configured to reduce the number of estimated filter coefficients used for emitter identification; a GMM-based signal classifier configured to identify the signal transmitted by the particular emitter as belonging to a specific device using the reduced number of estimated filter coefficients.