A security system comprises a positioning unit that determines locations of user devices relative to a threshold of the access point, a surveillance camera that monitors the threshold, and an access control system that controls the access point based on the locations of the user devices and orientations of individuals carrying the user devices relative to the access point. The surveillance camera is used to prevent tailgating. The cameras image data is also analyzed to determine the orientation of the individuals relative to the access point, such as a door. If the individuals are oriented such that they may be merely walking past the door, then access is not granted.