CONTINUOUS DATA OPTIMIZATION OF
NEW ACCESS POINTS IN POSITIONING
CROSS-REFERENCE TO RELATED
This application claims the benefit under 35 U.S.C. §119 (e) to the following Provisional Patent Application, the contents of which are incorporated herein in its entirety by reference:
U.S. Provisional Patent Application No. 60/654,811, filed on Feb. 22, 2005, entitled Continuous Data Optimization in Positioning System.
This application is a continuation-in-part of and claims the benefit under 35 U.S.C. § 120 to the following application, the contents of which are incorporated herein in its entirety by reference:
U.S. patent application Ser. No. 11/261,988, filed on Oct. 28, 2005, entitled Location-Based Services that Choose Location Algorithms Based on Number of Detected Access Points Within Range of User Device.
This application is related to the following U.S. Patent Applications, filed on an even date herewith, entitled as follows:
U.S. patent application Ser. No. 11/359,154 Continuous Data Optimization of Moved Access Points in Positioning Systems; and
U.S. patent application Ser. No. 11/359,271 Continuous Data Optimization by Filtering and Positioning Systems.
This application is related to the following U.S. Patent Applications filed on Oct. 28, 2005, entitled as follows:
U.S. patent application Ser. No. 11/261,848, Filed on Oct. 28, 2005, entitled Location Beacon Database;
U.S. patent application Ser. No. 11/261,898, Filed on Oct. 28, 2005, entitled Server for Updating Location Beacon Database; and
U.S. patent application Ser. No. 11/261,987, Filed on Oct. 28,2005, entitled Method and System for Building a Location Beacon Database.
This application is related to U.S. Provisional Patent Application No. 60/658,481, filed on Mar. 4, 2005, entitled Encoding and Compressing the Access Point Database.
1. Field of the Invention
The invention is generally related to location-based services and, more specifically, to methods of continuously optimizing or improving the quality of WiFi location data in such systems.
2. Discussion of Related Art
In recent years the number of mobile computing devices has increased dramatically creating the need for more advanced mobile and wireless services. Mobile email, walkie-talkie services, multi-player gaming and call following are examples of how new applications are emerging on mobile devices. In addition, users are beginning to demand/ seek applications that not only utilize their current location but also share that location information with others. Parents wish to keep track of their children, supervisors need to track the location of the company's delivery vehicles, and a business traveler looks to find the nearest pharmacy to pick up a prescription. All of these examples require the individual to know their own current location or that of someone else. To
date, we all rely on asking for directions, calling someone to ask their whereabouts or having workers check-in from time to time with their position.
Location-based services are an emerging area of mobile
5 applications that leverages the ability of new devices to calculate their current geographic position and report that to a user or to a service. Some examples of these services include local weather, traffic updates, driving directions, child trackers, buddy finders and urban concierge services. These new
10 location sensitive devices rely on a variety of technologies that all use the same general concept. Using radio signals coming from known reference points, these devices can mathematically calculate the user's position relative to these reference points. Each of these approaches has its strengths and
15 weaknesses based on the radio technology and the positioning algorithms they employ.
The Global Positioning System (GPS) operated by the U.S. Government leverages dozens of orbiting satellites as reference points. These satellites broadcast radio signals that are
20 picked up by GPS receivers. The receivers measure the time it took for that signal to reach to the receiver. After receiving signals from three or more GPS satellites the receiver can triangulate its position on the globe. For the system to work effectively, the radio signals must reach the received with
25 little or no interference. Weather, buildings or structures and foliage can cause interference because the receivers require a clear line-of-sight to three or more satellites. Interference can also be caused by a phenomenon known as multi-path. The radio signals from the satellites bounce off physical structures
30 causing multiple signals from the same satellite to reach a receiver at different times. Since the receiver's calculation is based on the time the signal took to reach the receiver, multipath signals confuse the receiver and cause substantial errors. Cell tower triangulation is another method used by wireless
35 and cellular carriers to determine a user or device's location. The wireless network and the handheld device communicate with each other to share signal information that the network can use to calculate the location of the device. This approach was originally seen as a superior model to GPS since these
40 signals do not require direct line of site and can penetrate buildings better. Unfortunately these approaches have proven to be suboptimal due to the heterogeneous nature of the cellular tower hardware along with the issues of multi-path signals and the lack of uniformity in the positioning of cellular
Assisted GPS is a newer model that combines both GPS and cellular tower techniques to produce a more accurate and reliable location calculation for mobile users. In this model, the wireless network attempts to help GPS improve its signal
50 reception by transmitting information about the clock offsets of the GPS satellites and the general location of the user based on the location of the connected cell tower. These techniques can help GPS receivers deal with weaker signals that one experiences indoors and helps the receiver obtain a 'fix'on the
55 closest satellites quicker providing a faster "first reading". These systems have been plagued by slow response times and poor accuracy—greater than 100 meters in downtown areas.
There have been some more recent alternative models developed to try and address the known issues with GPS,
60 A-GPS and cell tower positioning. One of them, known as TV-GPS, utilizes signals from television broadcast towers. (See, e.g., Muthukrishnan, Maria Lijding, Paul Havinga, Towards Smart Surroundings: Enabling Techniques and Technologies for Localization, Lecture Notes in Computer
65 Science, Volume 3479, Jan 2Hazas, M., Scott, J., Krumm, J.: Location-Aware Computing Comes of Age. IEEE Computer, 37(2):95-97, Feb. 2004 005, Pa005, Pages 350-362.) The