Patent ID: 8749432

Claim:
A satellite signal determination apparatus for a moving vehicle, the apparatus comprising: a GPS receiver provided inside of the vehicle to receive satellite signals transmitted from a plurality of satellites for positioning; a vehicle direction estimation section that estimates an absolute direction of a heading direction of the vehicle based on (i) GPS information outputted from the GPS receiver based on the satellite signals transmitted from the plurality of satellites, or (ii) vehicle information of the vehicle detected by a detection section; a satellite direction estimation section that estimates an absolute direction of an existing position of a target satellite, which is one of the plurality of satellites, using the GPS information outputted from the GPS receiver based on the satellite signal from the target satellite; a relative direction calculation section that calculates a relative direction of the target satellite with respect to the heading direction of the vehicle based on (i) the absolute direction of the heading direction of the vehicle estimated by the vehicle direction estimation section, and (ii) the absolute direction of the target satellite estimated by the satellite direction estimation section; and a shield determination section that determines a shielded state of the target satellite by determining whether a signal strength of a satellite signal transmitted from the target satellite is greater than a predetermined threshold value relative to a target partition within a plurality of partitions into which a three-dimensional sphere with respect to the heading direction of the vehicle is divided, the target partition which the relative direction of the target satellite calculated by the relative direction calculation section belongs to.