Wi-Fi assistance to a SUPL based A-GPS simulator for indoor positioning.

摘要

The need for accurate positioning systems is on the rise and so is the need for testing positioning devices working on one of the many positioning technologies. Though Global Positioning System (GPS) has been the most popular choice for positioning, its limitation in working indoors has led to the extended use of Assisted GPS (A-GPS). The introduction of 3rd Generation (3G) mobile phones like the Apple iPhone has popularized the use of Wi-Fi Positioning System (WPS). This thesis focuses on providing Wi-Fi assistance to a Secure User Plane Location based A-GPS simulator. The A-GPS simulator is implemented using National Instruments' LabVIEW GPS simulator and a SUPL protocol based support or assistance wherein a location ID is provided by the A-GPS receiver or the client. In this thesis, the client is a laptop and the location ID can either be IP address or MAC address. The server that houses the simulator returns a coarse location to the client based on the location ID it receives, along with assistance data such as almanac, ephemeris and coarse time generated by the GPS simulator. If the location ID is the IP address, the server makes use of Ip2location's database to retrieve the location information whereas in the case of the MAC address being the location ID, the client itself makes use of Skyhook's WPS SDK to calculate a reference location. It sends this information to the server so that this reference location can be packed with the other assistance data and sent back to itself. A laptop is used as the client/ A-GPS receiver to demonstrate more clearly, the Wi-Fi assistance. This A-GPS simulator is an inexpensive solution for testing A-GPS receivers and is most suitable for academic institutions.