Patent ID: 9026135
Filing Date: 2015-05-05
Classification: G01S

Abstract:
1. A mobile terminal device capable of selectively performing a plurality of different positioning methods for acquiring location information of the mobile terminal device in a repeated manner, the mobile terminal device comprising: a positioning timing base unit for giving a positioning timing base signal to be a basis for specifying a timing of performing each positioning operation, when the positioning operation is performed in the repeated manner; a positioning result holding unit for at least temporarily holding positioning data corresponding to a result of the each positioning operation; an A-GPS positioning unit for performing an A-GPS positioning operation at the timing in synchronization with the positioning timing base signal given by the positioning timing base unit, the A-GPS positioning operation including an assist information acquiring process for acquiring GPS assist information including outline location information of the mobile terminal device in communication with a base transceiver station, and a positioning operation process by use of the GPS assist information acquired by the assist information acquiring process; an autonomous GPS positioning unit for performing an autonomous GPS positioning operation without using the GPS assist information at the timing in synchronization with the positioning timing base signal given by the positioning timing base unit; an environment estimating unit for estimating whether or not the mobile terminal device is currently located in an indoor environment or in an outdoor environment; an autonomous GPS positioning regulating unit for regulating implementation of the autonomous GPS positioning operation by the autonomous GPS positioning unit to cause the A-GPS positioning unit to perform the assist information acquiring process of the A-GPS positioning operation, when the environment estimating unit estimates that the mobile terminal device is currently located in the indoor environment, and at a time after the estimation, when the positioning timing base unit gives the positioning timing base signal; an assist information holding unit for holding the GPS assist information acquired by the assist information acquiring process by the A-GPS positioning unit; an outline location information accuracy determining unit for determining whether or not accuracy of a location of the outline location information of the mobile terminal device included in the GPS assist information held by the assist information holding unit satisfies a predefined level; and a positioning operation process regulating unit for regulating implementation of the positioning operation process by the A-GPS positioning unit and causing the positioning result holding unit to hold as the positioning data the outline location information on which a positive determination is made by the outline location information accuracy determining unit, when the outline location information accuracy determining unit makes the positive determination, and at a time after the determination, when the positioning timing base unit gives the positioning timing base signal.