A Multisensor Approach to Covert Acoustic Calibration of Littoral Environments Using Sources of Opportunity

Syntonics proposes to develop a precision time and frequency source with excellent intermediate-term timing stability (accuracy better than 1e-12 seconds over several hours), long life and high reliability. This intermediate-term precision time andfrequency source will use a time scale generator based on an ensemble of small quartz oscillators. This product would give the Navy an inexpensive time and frequency standard with the precision necessary for the Navigation System Sensor Interface (NAVSSI)and Link-16 terminal, but with significantly higher reliability and longer service life that any solution using an atomic physics package.An inexpensive, highly reliable and long-lived time source with the signal purity and short-term (i.e., up toapproximately 20 minutes) stability of a good quartz oscillator, and with the intermediate-term (i.e., 20 minutes to one day) stability of an atomic standard would have numerous commercial applications. Today's marketplace offers a variety of cesium- orrubidium-based frequency sources with good intermediate- and long-term time stability, but their short-term stability and phase noise performance is inferior to a precision quartz oscillator. Further, they are relatively expensive, unreliable andshort-lived compared to quartz oscillators.