Using time-frequency analysis to determine time-resolved detonation velocity with microwave interferometry

• Published in: Review of scientific instruments 2015-04, Vol.86 (4), p.044705-044705
• Main Authors: Kittell, David E, Mares, Jr, Jesus O, Son, Steven F
• Format: Article
• Language: English
• Subjects: Ammonium nitrate; Continuous wavelet transform; Control methods; Detonation; Fourier transforms; Interferometry; Picking; Scientific apparatus & instruments; Signal quality; TATB; Time-frequency analysis; Velocity; Wavelet transforms
• ISSN: 0034-6748; 1089-7623
• DOI: 10.1063/1.4916733

Two time-frequency analysis methods based on the short-time Fourier transform (STFT) and continuous wavelet transform (CWT) were used to determine time-resolved detonation velocities with microwave interferometry (MI). The results were directly compared to well-established analysis techniques consisting of a peak-picking routine as well as a phase unwrapping method (i.e., quadrature analysis). The comparison is conducted on experimental data consisting of transient detonation phenomena observed in triaminotrinitrobenzene and ammonium nitrate-urea explosives, representing high and low quality MI signals, respectively. Time-frequency analysis proved much more capable of extracting useful and highly resolved velocity information from low quality signals than the phase unwrapping and peak-picking methods. Additionally, control of the time-frequency methods is mainly constrained to a single parameter which allows for a highly unbiased analysis method to extract velocity information. In contrast, the phase unwrapping technique introduces user based variability while the peak-picking technique does not achieve a highly resolved velocity result. Both STFT and CWT methods are proposed as improved additions to the analysis methods applied to MI detonation experiments, and may be useful in similar applications.