A location determining system, comprising: a mobile tag (101, 550, 700) positioned at a first location within a structure, the structure including a plurality of second locations; a plurality of sensors (121, 122, 123, 124, 125, 131, 132, 133, 134, 135) positioned at different locations of the structure, the plurality of sensors (121, 122, 123, 124, 125, 131, 132, 133, 134, 135) being configured to sense a structure condition; and a controller, the controller operating to: determine a plurality of possible paths of the mobile tag (101, 550, 700) within the structure; generate a distance likelihood map representing the possible paths of the mobile tag (101, 550, 700) and probabilities of the mobile tag taking the possible paths based on the plurality of possible paths and distances between the first location and the plurality of second location; generate a radio frequency - RF - likelihood map wherein at least some of the plurality of sensors (121, 122, 123, 124, 125, 131, 132, 133, 134, 135) are RF sensors which are distributed throughout one or more areas of the structure and are configured to detect RF beacons transmitted by the mobile tag (101, 550, 700); generate a motion likelihood map wherein at least some of the plurality of sensors (121, 122, 123, 124, 125, 131, 132, 133, 134, 135) are motion sensors which are distributed throughout one or more areas of the structure and are configured to detect movement in proximity to each sensor; generate a structure likelihood map wherein the likelihood of the mobile tag's position or movement is based on the location of boundaries and passages within the structure; and determine a location of the mobile tag (101, 550, 700) within the structure based on a final map which is generated by combining the distance likelihood map, the radio frequency - RF - likelihood map, the motion likelihood map and the structure likelihood map. a mobile tag (101, 550, 700) positioned at a first location within a structure, the structure including a plurality of second locations; a plurality of sensors (121, 122, 123, 124, 125, 131, 132, 133, 134, 135) positioned at different locations of the structure, the plurality of sensors (121, 122, 123, 124, 125, 131, 132, 133, 134, 135) being configured to sense a structure condition; and a controller, the controller operating to: determine a plurality of possible paths of the mobile tag (101, 550, 700) within the structure; generate a distance likelihood map representing the possible paths of the mobile tag (101, 550, 700) and probabilities of the mobile tag taking the possible paths based on the plurality of possible paths and distances between the first location and the plurality of second location; generate a radio frequency - RF - likelihood map wherein at least some of the plurality of sensors (121, 122, 123, 124, 125, 131, 132, 133, 134, 135) are RF sensors which are distributed throughout one or more areas of the structure and are configured to detect RF beacons transmitted by the mobile tag (101, 550, 700); generate a motion likelihood map wherein at least some of the plurality of sensors (121, 122, 123, 124, 125, 131, 132, 133, 134, 135) are motion sensors which are distributed throughout one or more areas of the structure and are configured to detect movement in proximity to each sensor; generate a structure likelihood map wherein the likelihood of the mobile tag's position or movement is based on the location of boundaries and passages within the structure; and determine a location of the mobile tag (101, 550, 700) within the structure based on a final map which is generated by combining the distance likelihood map, the radio frequency - RF - likelihood map, the motion likelihood map and the structure likelihood map. determine a plurality of possible paths of the mobile tag (101, 550, 700) within the structure; generate a distance likelihood map representing the possible paths of the mobile tag (101, 550, 700) and probabilities of the mobile tag taking the possible paths based on the plurality of possible paths and distances between the first location and the plurality of second location; generate a radio frequency - RF - likelihood map wherein at least some of the plurality of sensors (121, 122, 123, 124, 125, 131, 132, 133, 134, 135) are RF sensors which are distributed throughout one or more areas of the structure and are configured to detect RF beacons transmitted by the mobile tag (101, 550, 700); generate a motion likelihood map wherein at least some of the plurality of sensors (121, 122, 123, 124, 125, 131, 132, 133, 134, 135) are motion sensors which are distributed throughout one or more areas of the structure and are configured to detect movement in proximity to each sensor; generate a structure likelihood map wherein the likelihood of the mobile tag's position or movement is based on the location of boundaries and passages within the structure; and determine a location of the mobile tag (101, 550, 700) within the structure based on a final map which is generated by combining the distance likelihood map, the radio frequency - RF - likelihood map, the motion likelihood map and the structure likelihood map.