US Patent 10165542 Localization of a mobile device

A method of determining a location of a mobile device based on a first location estimation performed using a first location system, the method comprising: obtaining an initial estimate of the mobile device's location based on a second location estimation that is coarser than the first location estimation; using the initial estimate to select a subset of the reference nodes of the first network that are within a defined vicinity of the mobile device's location; and from amongst a database of respective assistance data for each of the wireless reference nodes stored on a server of the first location system, selectively providing the respective assistance data for each of said subset of wireless reference nodes to a localization module on the mobile device, for the localization module of the mobile device to calculate a finer estimate of the mobile device's location.