WORK MACHINE

A controller sets, as a satellite mask range, a range for which a work implement can become an obstacle when an antenna receives positioning signals from a plurality of positioning satellites on the basis of a position at which the antenna is installed, a movable range of the work implement, a posture of an upper swing structure, and an azimuth angle of the upper swing structure. The controller cancels the setting of the satellite mask range in a case where it has been determined, on the basis of satellite positioning condition data acquired from a receiver, that the setting of the satellite mask range leads to reduced precision of positioning computation by the receiver. In a case where the setting of the satellite mask range has been canceled, the receiver computes the position of the upper swing structure on the basis of the positioning signals transmitted from the plurality of positioning satellites.