A process and machine for estimating the location of a wireless terminal
is disclosed. The illustrative embodiment of the present invention is
based on the observation that the signal strength of a signal from a
transmitter is different at some locations, and, therefore, the location
of a wireless terminal can be estimated by comparing the signal strength
it currently observes against a map or database that correlates locations
to signal strengths. In accordance with a first example, if a particular
radio station is known to be received well at a first location and poorly
at a second location, and a given wireless terminal at an unknown
location is receiving the radio station poorly, it is more likely that
the wireless terminal is at the second location than it is at the first
location.