公开(公告)号：US09758183B2

公开(公告)日：2017-09-12

申请号：US14502653

申请日：2014-09-30

Applicant: Apple Inc.

Inventor： David Benjamin Millman ,  Johan Olav Bergerengen ,  Robert Mayor ,  Brian Stephen Smith

IPC: G01S5/02 ,  B61L25/02 ,  G01C21/20 ,  H04W4/02 ,  B61L15/00 ,  B61L27/00 ,  H04W4/04 ,  H04W64/00

CPC classification number: B61L25/025 ,  B61L15/0027 ,  B61L27/0005 ,  G01C21/20 ,  G01S5/0252 ,  H04W4/02 ,  H04W4/046 ,  H04W64/00

Abstract: Methods, program products, and systems for building a location fingerprint database for a transit system are described. The transit system can be a subway system including underground train stations and routes where location determination using GPS signals is difficult or impossible. A sampling device can measure signals, e.g., radio frequency (RF) signals detected at the stations or on the routes. A location server can construct a location fingerprint for each of the stations and the routes. Each location fingerprint can represent expected signal measurements by a user device if the user device is located at the respective station or route. The location server can provide the location fingerprint to a user device for the user device to determine a location of the user device within the station or on the route.