A mobile communication device includes, in part, a first wireless receiver adapted to determine, as it travels along a path, a multitude of positions of the mobile communication device using signals received from a primary positioning source, a second wireless receiver adapted to receive signals from one or more ambient wireless sources as the mobile communication device travels along the path, and a positioning module. An internal or external memory stores estimated positions and corresponding time references of the signals of the one or more ambient sources. The positioning module uses the data stored in the database to estimate the position of the mobile communication device when no primary positioning source signal is available. The positioning module optionally uses the data stored in the database to improve estimates of the position of the mobile communication device when primary positioning signal is available.