An underwater vehicle including an axi-symmetric framing system rotatable about a centerline to define a shell of revolution having a uniformly-convex outer boundary. A narrow-beam sonar array is mounted on the axi-symmetric framing system, and includes a multitude of simultaneously-fireable and/or asynchronously-fireable transducers distributed substantially evenly over a 4π-steradian viewing angle. The present invention provides the necessary configuration for a vehicle wherein an internal algorithm can compare a “new” geometry to an “old” geometry collected earlier to construct a best fit of the new world map with the old world map and locate the vehicle within the context of the new world map. This then provides a completely independent mechanism for correction of the gradual drift in x and y that is not dependent on any form of external navigation aid.