US 6,393,294 B1 · Location determination using RF fingerprinting

Abstract

A method for determining the location of a mobile unit (MU) in a wireless communication system and presenting it to a remote party. The location of a remote MU is determined by comparing a snapshot of a predefined portion of the radio-frequency (RF) spectrum taken by the MU to a reference database containing multiple snapshots taken at various locations. The result of the comparison is used to determine if the MU is at a specific location. The comparison may be made in the MU, or at some other location situated remotely from the MU. In the latter case, sufficient information regarding the captured fingerprint is transmitted from the MU to the remote location. The database may be pre-compiled or generated on-line.

Claims36

Dependent claims

A method for locating the position of a mobile unit in a wireless communication network, the method comprising:

providing a fingerprint database having a multiplicity of RF fingerprints, each fingerprint in the fingerprint database having an associated unique location;
generating a location probability distribution by assigning respective probabilities to locations associated with fingerprints in the fingerprint database;
capturing an RF fingerprint in the mobile unit;
updating the location probability distribution using the fingerprint, so captured, and the fingerprint database by generating an additional probability distribution based on the fingerprint database and the fingerprint, so captured, and combining the additional probability distribution with the location probability distribution to generate an updated location probability distribution;
and
using the updated location probability distribution to generate an estimate of the position of the mobile unit.

3 more elements

A method for locating the position of a mobile unit in a wireless communication network, the method comprising:

providing a fingerprint database having a multiplicity of RF fingerprints, each fingerprint in the fingerprint database having an associated unique location;
providing a Markov model that provides, for at least one location, transition probabilities that the mobile unit at that location will transition to other locations within a time interval between successive fingerprint captures;
generating a location probability distribution by assigning respective probabilities to locations associated with fingerprints in the fingerprint database;
capturing a series of fingerprints in the mobile unit at different times;
for each newly captured fingerprint, recursively updating the location probability distribution, each updating being performed by:
subjecting the previous version of the location probability distribution to the Markov model to provide a predicted probability distribution reflecting the transition probabilities in the Markov model,
comparing the newly captured fingerprint with the fingerprint database to generate an additional probability distribution based on the fingerprint database and the newly captured fingerprint, and
combining the additional probability distribution with the predicted probability distribution to provide the newly updated location probability distribution;
and
using an updated version of the location probability distribution to generate an estimate of the position of the mobile unit.

7 more elements

Dependencies are inferred from the claim text.

Location determination using RF fingerprinting

Life of this patent

Location determination using RF fingerprinting

Life of this patent

Abstract

Claims36