Non-invasive, stealthy nature of passive remote sensing combined with its low cost make passive techniques a promising supplement or replacement of traditional active remote sensing techniques. Coherent processing of diffuse wave fields has a proven potential for remote sensing of stationary environments. The proposed research extends noise interferometry to characterization of dynamic environments. We will develop acoustic daylight and radio wave daylight techniques for retrieval of information about targets and their surroundings from the ambient acoustic noise and the background radio waves; and determine which environmental parameters and types of targets can be effectively monitored through ambient noise interferometry. During Phase I we propose to demonstrate experimentally the feasibility of passive acoustic measurements of sound speed and flow velocity in a moving fluid and to evaluate necessary noise averaging times and receiver network geometry for detection of targets and achieving desired accuracy of passive acoustic measurements of environmental parameters. In case of positive results of Phase I, the efforts of Phase I optional part and Phase II will be directed toward extension of the interferometric approach to ambient acoustic noise in the ocean and to electromagnetic ambient noise in the microwave band in the atmosphere as well as to optimization of the data acquisition geometry, frequency band, and data processing algorithms to improve accuracy of passive travel time measurements and sensitivity to weak, transient environmental perturbations.
Benefit: The result of the Phase II&III efforts will be a sensor system or systems and data processing algorithms capable of measuring physical parameters of dynamic environments, such as ocean and its surface, using ambient noise fields as a probing signal. Such a system would be of great value to NAVAIR and the Navy for national security purposes, and to other parts of the US Government for environmental monitoring and resource management. Specific applications may include monitoring and quantification of climate change through passive acoustic thermometry of the ocean, continuous measurements of heat and mass transport through straits, census of megafauna in specific ocean basins, and monitoring pollutant transport in coastal waters. Most of ZelTechs prior commercialization has been the technology transition of R&D prototypes and processes from the laboratory to fielded, operational military systems. We have proven capabilities to develop a prototype system based on this research, and assist in its transition to operational use within NAVAIR and other US Navy and Government organizations.
Keywords: Noise Interferometry, Noise Interferometry, Ocean Current Tomography, Transient Environmental Perturbations, Ambient Noise, Remote Sensing, Passive Detection And Localization,
