Even in a case where positioning precision of positioning using a GPS signal or output data of an internal sensor is low, a location is precisely estimated. For example, a location of a moving object is estimated based on a relative locational relationship between at least two landmarks or at least two transmitters and the moving object. The location of the moving object may also be estimated based on a relative locational relationship between at least two parts of a single landmark and the moving object. The location of the moving object may also be estimated based on a relative locational relationship between a single transmitter that has output two signals and the moving object. The location of the moving object may also be estimated based on a relative locational relationship between each of at least one landmark and at least one transmitter, and the moving object.