1. A method of determining the relative location of a mobile object, the method comprising: receiving an estimated location for the mobile object from the mobile object, the mobile object using a location determination mechanism to approximate its estimated location; defining a reverse geofence boundary around the estimated location of the mobile object, the reverse geofence boundary defining an area where the mobile object is located; identifying a set of known locations within the reverse geofence boundary from a database of known locations; calculating a relative probability for each known location in the set of known locations that indicates a relative likelihood of where the mobile object is actually located; and determining the most probable location of the mobile object based on the calculations.