Systems and techniques for location determination. A plurality of tags emitting
radio frequency signals are dispersed throughout a region, such as a building,
within which a user's location is to be determined. The radio frequency signals
emitted by the tags include information that can be used to identify the location
in which the tags axe placed, or simply to distinguish the tags from one another.
A portable device receives signals from the tags and provides the signal information
to a location server that computes the location of the portable device by comparing
the signal information received from the portable device to a map of location venus
stored signal information, and identifies the location of the portable device as
the location for which the stored signal information best matches the signal information
received from the portable device.
