1. A system, comprising: a movable object having an unknown location, the movable object comprising: at least one mobility sensor to detect physical movement of the movable object and to provide sensory information pertaining to movement of the movable object, a wireless communications package to provide received signal strength indication (RSSI) information, and a processing unit coupled to the at least one mobility sensor and to the wireless communications package, the processing unit to cause the wireless communications package to transmit data about the movable object, the data including the sensory information and the RSSI information; a receiver to receive the data about the movable object; and at least one algorithm stored in the receiver, the algorithm, when executed by the receiver, to perform operations comprising: creating a mobility model for the movable object, based at least in part on the sensory information from the moveable object pertaining to movement of the movable object; creating a measurement model for the moveable object, based at least on part on the RSSI information; and calculating a location estimate for the movable object, based at least in part on the mobility model and the measurement model; wherein the operation of creating the measurement model comprises creating a probability distribution of estimated locations for the movable object at particular points in time, based at least in part on the RSSI information; wherein creation of the probability distribution involves (a) calculating probabilities for particles based on current states of the particles inside the filter, (b) using the calculated probability for each particle to weigh said particle, (c) creating a cumulative distribution of new weights of all particles, and (d) using the cumulative distribution to resample each particle so the particles have uniform weights; wherein the operation of resampling each particle so the particles have uniform weights comprises potentially moving a particle from a less likely estimated location to a more likely estimated location; and wherein the operation of calculating the location estimate for the movable object, comprises: displacing the resampled particles, based on the mobility model; and after displacing the resampled particles, selecting a displaced particle as the location estimate for the moveable object, based at least in part on probabilities associated with the displaced particles.