Innovative Infrasound Sensors with High Reduction of Natural Background Noise

Period of Performance: 05/02/2000 - 12/02/2000


Phase 1 SBIR

Recipient Firm

Physical Sciences, Inc.
Principal Investigator


A global array of infrasonic sensors to monitor compliance is specified in the Comprehensive Nuclear Test Ban Treaty. A prototype system of infrasonic sensor stations has been defined but this design is not considered optimal and greater signal to noise and less sensitivity to local conditions (e.g. snow) are sought. PSI will design an innovative replacement sensor subsystem using PVDF piezopolymer sheets or cable. This sensor material has good sensitivity and dynamic range and its properties are well known and uniform. The sensors will be continuous and can provide optimal pressure averaging for local noise suppression and a variety of sensor shapes and sizes will be evaluated. Sensor subsystems will also be all electronic thereby eliminating the need for manifolds and microbarographs in the present system and making possible processing of individual sensors for enhanced signal and noise performance. In Phase I, a simple sensor model will be constructed and validated by experiments with sensors of various sizes. A prototype subsystem including sensors, electronics and signal processing will be defined and itsfeasibility demonstrated in a set of field tests using a full size subsystem. The innovative sensor system will provide better acoustic performance, be less sensitive to environmental factors and require less maintenance than the current baseline system at comparable or lower cost. It will replace the complexities and uncertainties of the present system which uses a microbarograph attached by a manifold to a series of hardware store hoses by a uniform, well characterized state of the art sensor with direct electrical outputs, which will support novel sensor signal processing including monitoring of individual array elements. In addition to test ban treaty monitoring, there are several potential commercial applications of infrasonic sensors including avalanche detection, turbulence monitoring and tornado detection and warning. The technology developed in this program will allow the development of affordable large arrays of well calibrated sensors that will be required for these applications.