Geophysical navigation technologies and applications

The U.S. Navy's submarine fleet has a wide array of navigation requirements. SSBNs must maintain high-accuracy navigation over long periods in blue water without exposure. SSNs, SSGNs and UUVs must be able to operate covertly in littoral waters for extended durations. In the future, submarines must be capable of conducting these missions with increased performance both with and without GPS. These future submarine navigation capabilities are necessary for the Navy to achieve its goals for Precision Engagement and Full Dimensional Protection using Network Centric Warfare concepts. Network Centric Warfare emphasizes systems rather than platforms, and uses advanced communications to network individual platforms to provide significant improvement to their collective performance. In order to share intelligence effectively across platforms, each platform must maintain an accurate knowledge of its position. Common to all of the U.S. Navy's current requirements and future plans is the need for submarine navigators to covertly maintain accurate outputs with reduced dependence on GPS. With this view toward current and future submarine navigation requirements, Lockheed Martin Maritime Systems and Sensors (MS2) Mitchel Field has been developing geophysical navigation technologies to enhance submarine navigation performance and reduce dependence on GPS. Most recently MS2 has successfully demonstrated a next generation bathymetric fix technology that maintains performance while eliminating the operational restrictions inherent in the current technology. MS2 has also successfully demonstrated our unique gravity navigation technology based on gravimeters and gradiometers aboard SSN691 Memphis. This paper discusses MS2's bathymetric and gravity technologies as well as velocity sonar techniques and cost effective approaches for implementing these capabilities on SSN and potentially UUV platforms.