The semi-outdoor space covered with the upper part and open on the side is difficult to apply the existing indoor-outdoor seamless methods because the GPS positioning accuracy is reduced but some degree of GPS signal can be received. In order to detect a stay in such a special environment, we designed a method to select satellites for stay detection based on the spatial characteristics of the semi-outdoor space, which consists of three parameters: height, depth and side opening direction. Furthermore, since it is difficult to set a specific threshold for stay detection, we designed a decision flow to determine the stay by using fuzzy inference based on the values of signal-to-noise ratio of the selected satellites. Using this method, we confirmed that we could detect the stay in the semi-outdoor space covered by the upper part of the space with 89.4% probability at three evaluation experimental locations.