The present invention leverages changes in the sensed strength of radio signals at different locations to determine a device's location. In one instance of the invention, inference procedures are used to process ambient commercial radio signals, to estimate a location or a probability distribution over the locations of a device. In an instance of the invention, learning and inference methods are applied to rank vector of signal strength vectors. Moving to such rank orderings leads to methods that bypass consideration of absolute signal strengths in location calculations. The invention facilitates approximations for locating a device by providing a method that does not require a substantial number of available ambient signal strengths while still providing useful location inferences in determining locations.