The conceptual architecture of an ocean acoustic system with the dual uses of submerged platform navigation and large-scale temperature measurement has been developed, and is described here. Swept FM signals would be used to synthesize short-duration pulses. A 50-Hz bandwidth is to be used, within the frequency range of 100 to 200 Hz. The potential performance of the system is discussed here. Navigation performance is compared with that of the currently used 1.6-Hz bandwidth RAFOS system. Thermometry performance can be evaluated using experiences with prior systems.