1. A method for determining a global position of an observed object, the method comprising: obtaining a first global position of an observed object with at least one positioning device; determining if a set of stored visual characteristic information of at least one landmark matches a visual characteristic information set obtained from at least one captured image comprising a scene associated with the observed object; and determining, in response to the set of stored visual characteristic information matching the obtained visual characteristic information set, a second global position of the observed object based on a set of stored location information associated with the at least one landmark and the first global position.