Mobile device geolocation

摘要

GPS receivers are included in many mobile communications devices; however, there are circumstances where GPS is unavailable or undesirable to use. In an implementation, a device identifies nearby wireless signals, such as Wi-Fi access points and cell towers, and compares them to a database of known signals to determine an approximate location for the device. Because such a database can be large and change rapidly, it may not be appropriate to store the database entirely on a device. Instead, a server may store the database. In an implementation, to minimize the time required to determine a device's location, the device may first transmit location-related information to a server and receive a subset of the database corresponding to an area near the device so that future locations nearby can be determined without needing to communicate with the server.

主权项

1. A method comprising:
transmitting to a server remote from a computing device first location-related information associated with a current location of the computing device, the first location-related information including identification and signal information for nearby Wi-Fi access points and cell towers and associated signal characteristics detected by the computing device at the current location; after the transmitting to the server, receiving at the computing device second location-related information from the server, wherein the server utilizes an external location service accessible via a Hypertext Transfer Protocol (HTTP) application programming interface (API) to estimate a location of the computing device based on the first location-related information, wherein the second location-related information represents a portion of a database of location-related information stored at the server that corresponds to an area around the device's estimated location, and wherein the second location-related information includes identification of at least one Wi-Fi access point or of at least one cell tower at or near the estimated location of the computing device; at the computing device, measuring signal strengths received from the at least one Wi-Fi access point or from the at least one cell tower included in the second location-related information; and at the computing device, estimating a new location of the computing device based on the second location-related information and the measured signal strengths from the at least one Wi-Fi access point or from the at least one cell tower included in the second location-related information.