Patent ID: 7609201
Filing Date: 2009-10-27
Classification: G01S

Abstract:
1. An apparatus comprising: a receiver which receives a device distance and a device position from a position detecting device which measures the device distance from the position detecting device to each of a plurality of satellites and calculates the device position that is the position of the position detecting device based on the device distance and the position of each of the plurality of satellites; a verification position calculator, coupled to said receiver, which calculates a verification position that is the position to be calculated by the position detecting device, based on the received device distance and the position of each of the plurality of satellites at the time of measuring the device distance; a validity circuit, coupled to said verification position calculator, which judges that the device position detected by the position detecting device is valid, on condition that the device position is coincident with the verification position; and a distance calculator, coupled to said validity circuit, which calculates the distance between the position of each of the plurality of satellites at the time of measuring the device distance by the position detecting device and the device position received by said receiver; wherein the validity circuit judges that the device position is valid, further provided that the device distance received by said receiver differs from the distance calculated by said distance calculator by a predetermined difference value or more.