Hybrid navigation system for long range operation

Describes a navigation system that allows long range navigation by combining two distinct modes: local positioning with respect to a long baseline array of known localization (reference points) and autonomous mode in-between reference points, relying only on sonar/Doppler and depth information. The areas of transponder-based navigation are defined by the maximum range of transponder operation. In both modes, a Kalman based design approach was chosen, using, when necessary, the available position estimates to characterize the errors associated with the filter inputs. The authors present simulation results that illustrate the system´s behavior for a typical maneuvering operation