A method for primarily sensor-based navigation includes: in a first time period, collecting geophysical position data using a GPS receiver of a navigation device; in the first time period, collecting a first set of accelerometer data using an accelerometer of the navigation device; analyzing the first set of accelerometer data to produce a first set of vertical vehicular motion data; generating a mapping association between the first set of vertical vehicular motion data and the geophysical position data; in a second time period after the first time period, collecting a second set of accelerometer data using the accelerometer; analyzing the second set of accelerometer data to produce a second set of vertical vehicular motion data; and calculating an estimated location of the vehicle by analyzing the second set of vertical vehicular motion data in light of the mapping association.