Abstract: An algorithm for emitter identification of a transmitting platform using microphone keyclick analysis, and a system utilizing said algorithm, wherein said algorithm processes audio signals to detect transmission activity on a radio channel in the audio frequency range, detects the boundaries of transmitter keyclicks at the beginning and end of said transmission; extracts keying envelopes from said detected keyclick boundaries; and analyzes said keying envelopes to extract features characteristic of said keyclicks. The algorithm and system then proceed to execute a decision function based on said extracted characteristic features to identify the platform of said transmitter based on the features of said keyclick. A second algorithm, which may be executed in parallel with the first by said system, processes said transmission data using a fast fourier transform, detecting gaps in said processed transmission data.

Abstract: An algorithm for emitter identification of a transmitting platform using spectral energy analysis, and a system utilizing said algorithm, wherein said algorithm processes audio signals from transmission data using a fast fourier transform, detecting gaps in said processed transmission data. It then extracts spectral features consisting of normalized energy per unit frequency from said gaps. The algorithm and system then proceed to execute a decision function based on said extracted characteristic features to identify the platform of said transmitter based on said features. A second algorithm, which may be executed in parallel with the first by said system, processes the same transmission data to detect transmission activity on a radio channel in the audio frequency range, and to detect the boundaries of transmitter keyclicks at the beginning and end of said transmission.