Patent attributes
Methods, program products, and systems for using a location fingerprint database to determine a location of a mobile device are described. A mobile device can use a location fingerprint database to determine the location where GPS signals are unavailable. A server can generate location fingerprint data for the database. The server can generate the location fingerprint data using crowd sourcing, using known locations of signal sources, or both. The server can receive, from a sampling device, measurements of environment variables, e.g., signals from a signal source at one or more sampling points. The server can extrapolate, from the received measurements, estimated measurements at one or more locations in a venue. The server can store the extrapolated measurements as location fingerprint data. The server can send the location fingerprint data to a mobile device for determining a location of the mobile device when the mobile device is at the venue.