Systems and methods for estimating whether a receiver is indoors or outdoors. Certain approaches evaluate data associated with a network of beacons to determine whether the receiver is indoors or outdoors. Such evaluation may include any of determining whether azimuthal angles corresponding to the beacons meet an azimuthal angle condition, determining whether elevation angles corresponding to the beacons meet an elevation angle condition, determining whether signal strengths corresponding to the beacons meet a signal strength condition, and determining whether other measurements associated with the beacons meet other measurement conditions.