Compact, Sensitive, Low-Power, Thin-Film Magnetometers for ASW Surveillance Systems

The advent of new underwater threats in the form of small, quiet, and in some cases autonomous vehicles renders existing anti-submarine warfare (ASW) sensor systems inadequate. These smaller vehicles can navigate in shallower waters where deep-oceanacoustic detection and tracking methods become unreliable. Modalities other than acoustic sensing become important. A new sensor capability is being developed under the DADS (Distributed Autonomous Deployable Sensors) program. Among them is magneticfield sensing. Present sensor technologies fail to meet at least one of the operational criteria: noise performance, low cost, small size, and low power. Thin-film sensor technologies, using various forms of magnetoresistance or spin-dependent electrontransport phenomena, offer the possibility of meeting all criteria. The team of Billingsley Magnetics, Inc., and Quantum Magnetics, Inc., proposes to test thin-film sensors from different foundries, using its advanced control and readout electronics thatdemonstrably extract the maximum performance from the sensor elements. It will also address the pressing problem of power consumption and develop a design to be implemented in Phase II. The team possesses the intimate familiarity with DADS operationalissues and requirements, the most advanced sensor electronics, and state-of-the-art magnetic sensor test facilities required to meet the program goals. Military applications include submarine surveillance, detection and tracking of military vehicles andpersonnel, and facility security systems. Numerous applications of magnetic sensing await sensor systems combining sufficiently high performance with sufficiently low power to become commercially viable. These include advanced weapon detection systemsfor security and many forms of noninvasive testing and inspection.