Micromachined Infrasound Sensors

The Groundbased Nuclear Detonation Detection Research and Development office seeks advanced technology for the monitoring of explosion events using infrasonic signatures. Silicon Audio, Inc. and The University of Texas at Austin are working together to develop a microelectromechanicalsystem (MEMS) based piezoelectric infrasonicsensor technology. The sensor aims to exceed all of the threshold specifications provided in the solicitation. Phase I focused on the development of a lowcost, robust, and ultralownoise transducer. The lowcost feature makes large discrete sensor arrays feasible, in which pressure sensing nodes are spread over hundreds of meters. In Phase II, we focus on three thrusts: (i) further improve the MEMS sensing structure, (ii) realize fully functional analogsensor nodes, and (iii) realize a deployable array by integrating an analogtodigital converter (ADC) to create a digital sensor and acquisition system. In addition to providing infrasound data, the digital sensing elements will be able to communicate selfhealth indicators and perform selfcalibration assessment of both frequency and phase response insitu. This third system integration thrust is motivated by our conversations with expert users that have taken place in Phase I, and also by National Nuclear Security Administration (NNSA)’s emphasis on calibration and selfhealth sensor monitoring per the original solicitation. Above all, users of infrasound equipment value assurance that collected data is legitimate and valid – owing to the expense and effort expended to collect and process data. The vision for Phase II as captured by the three thrusts is to realize a modern, smart sensor system. The developed technology will be modular, and applicable to smallarray and largearray systems. A PhaseII goal is to make the sensors highly portable and deployable in any terrain without the encumbrance of rigid pipes or even wires in the case of wireless telemetry systems.