Methods, apparatuses and systems of estimating a location of a device are disclosed. One method includes determining a first position of the device, sensing at least one magnetic anomaly at the first position, estimating a location of the magnetic anomaly relative to the first position by determining a plurality of magnetic properties of the magnetic anomaly based on sensed signals of at least a magnetic sensor, and estimating a second position of the device based on a sensed change in a distance from the magnetic anomaly to the device.