A computer based method for identifying a location of a mobile device, comprising: reporting, by a first access point, AP, of a plurality of wireless APs, an observed strength or attenuation of a first signal received from a second AP of the plurality of wireless APs; identifying a distance between the first AP and the second AP; calibrating a first base path loss function of the first AP for a candidate area within a building using the reported strength or attenuation of the first signal and the identified distance; reporting, by the second AP, an observed strength or attenuation of a second signal received from the first AP; calibrating a second base path loss function of the second AP for the candidate area using the reported strength or attenuation of the second signal and the identified distance; determining a first signal distance between a first grid space in the candidate area and the first AP using a first received signal strength, RSS, and the calibrated first base path loss function, the first RSS comprising an indication of mobile device signal strength received by the first AP; comparing the first signal distance with a first grid space distance, resulting in a first grid space likelihood score, the first grid space distance comprising a known distance between the first AP and the first grid space; determining a second signal distance between the first grid space in the candidate area and the second AP using a second RSS and the calibrated second base path loss function, the second RSS comprising an indication of mobile device signal strength received by the second AP; comparing the second signal distance with a second grid space distance, resulting in a second grid space likelihood score, the second grid space distance comprising a known distance between the first AP and the first grid space; and identifying the location of the mobile device based at least on the first grid space likelihood score and the second grid space likelihood score, at least a portion of the method implemented at least in part via a processing unit. reporting, by a first access point, AP, of a plurality of wireless APs, an observed strength or attenuation of a first signal received from a second AP of the plurality of wireless APs; identifying a distance between the first AP and the second AP; calibrating a first base path loss function of the first AP for a candidate area within a building using the reported strength or attenuation of the first signal and the identified distance; reporting, by the second AP, an observed strength or attenuation of a second signal received from the first AP; calibrating a second base path loss function of the second AP for the candidate area using the reported strength or attenuation of the second signal and the identified distance; determining a first signal distance between a first grid space in the candidate area and the first AP using a first received signal strength, RSS, and the calibrated first base path loss function, the first RSS comprising an indication of mobile device signal strength received by the first AP; comparing the first signal distance with a first grid space distance, resulting in a first grid space likelihood score, the first grid space distance comprising a known distance between the first AP and the first grid space; determining a second signal distance between the first grid space in the candidate area and the second AP using a second RSS and the calibrated second base path loss function, the second RSS comprising an indication of mobile device signal strength received by the second AP; comparing the second signal distance with a second grid space distance, resulting in a second grid space likelihood score, the second grid space distance comprising a known distance between the first AP and the first grid space; and identifying the location of the mobile device based at least on the first grid space likelihood score and the second grid space likelihood score, at least a portion of the method implemented at least in part via a processing unit.