Program Summary
The Global Positioning System (GPS) is the predominant means of obtaining positioning, navigation, and timing (PNT) information for both military and civilian systems and applications. However, the radio frequency basis for GPS also means that its signals cannot penetrate seawater, and thus undersea GPS is effectively denied. The Positioning System for Deep Ocean Navigation (POSYDON) program aims to develop an undersea system that provides omnipresent, robust positioning across ocean basins. By ranging to a small number of long-range acoustic sources, an undersea platform would be able to obtain continuous, accurate positioning without surfacing for a GPS fix. Phase I of the program focuses on accurately modeling the signal propagation channel, and Phase II focuses on developing the signal waveform. A complete positioning system is scheduled to be demonstrated in Phase III.