Positioning system

Abstract

There is disclosed a method of managing a database of positioning data, the positioning data including electromagnetic signal source data for use by a positioning system, and the method comprising: receiving signal data relating to signals received from a plurality of electromagnetic signal sources; associating an appropriate one of a plurality of zone identifiers with each of the electromagnetic signal sources, each zone identifier being associated with a respective geographical zone; selecting a subset of the plurality of electromagnetic signal sources in dependence on their associated zone identifiers; processing the signal data relating to the subset of the plurality of electromagnetic signal sources to compute position estimates of the electromagnetic signal sources; and updating the database of electromagnetic signal source data in dependence on the computed position estimates.

1 . A method of managing a database of positioning data, the positioning data including electromagnetic signal source data for use by a positioning system, and the method comprising:
 receiving signal data relating to signals received by user devices from a plurality of electromagnetic signal sources;   associating each of the electromagnetic signal sources with an appropriate geographical region selected from a plurality of geographical regions;   selecting a subset of the plurality of electromagnetic signal sources in dependence on their associated geographical regions;   processing the signal data relating to the subset of the plurality of electromagnetic signal sources to compute position estimates of the electromagnetic signal sources; and   updating the database of electromagnetic signal source data in dependence on the computed position estimates.   
     
     
         2 . A method according to  claim 1 , wherein selecting a subset of signal sources comprises selecting signal sources associated with geographical regions that have a relatively poor coverage in the database. 
     
     
         3 . A method according to  claim 1 , wherein the electromagnetic signal source data relating to the selected subset of signal sources is updated before the electromagnetic signal source data relating to the non-selected signal sources. 
     
     
         4 . A method according to  claim 1 , further comprising processing the selected subset of signal sources substantially in realtime and/or on demand. 
     
     
         5 . A method according to  claim 1 , further comprising processing the non-selected signal sources on a periodic basis, as a batch job and/or when a processing load falls below a threshold amount. 
     
     
         6 . A method according to  claim 1 , further comprising assigning a priority to each of the signal sources, and processing the signal sources substantially in order of said priority. 
     
     
         7 . A method according to  claim 1 , wherein updating the database comprises at least one of: updating a database entry and adding a database entry. 
     
     
         8 . A method according to  claim 1 , wherein whilst the device is in continuous communication with an electromagnetic signal source of the subset of electromagnetic signal sources, the method comprises: estimating the position of the device using an estimate of the position of the said electromagnetic signal source from the database prior to the step of updating the database of electromagnetic signal source data; obtaining an updated estimate of the position of the said electromagnetic signal source; and estimating an updated position of the device using the updated estimate of the position of the said electromagnetic signal source. 
     
     
         9 . A method according to  claim 8  wherein the step of obtaining an updated estimate of the position of the electromagnetic signal source comprises obtaining an updated estimate of the position of the electromagnetic signal source from the database after the step of updating the database has been performed. 
     
     
         10 . A method according to  claim 8  further comprising outputting the position and the updated position to a user whilst the device is in continuous communication with the said electromagnetic signal source. 
     
     
         11 . A method according to  claim 1 , further comprising:
 receiving local signal data relating to signals received at a user device from a plurality of electromagnetic signal sources local to the user device;   processing the local signal data in dependence on the electromagnetic signal source data to generate an estimate of the position of the user device; and   outputting the estimate of the position of the user device.   
     
     
         12 . A method according to  claim 1 , wherein the database is a local database that is at least a partial copy of a master database. 
     
     
         13 . A method according to  claim 12 , further comprising synchronizing the local database and the master database. 
     
     
         14 . A method according to  claim 13 , wherein the position estimate of the user device is outputted before the local database is synchronized with the master database. 
     
     
         15 . A device operable to use a positioning system that generates position estimates in dependence on signal data relating to signals received at the device from a plurality of electromagnetic signal sources, the device comprising:
 a receiver for receiving at least one signal from a respective at least one electromagnetic signal source;   a processor; and   computer program code for causing the processor, in use, to carry out the method of  claim 1 .   
     
     
         16 . A server operable to provide a positioning system for a device, the positioning system being operable to generate position estimates in dependence on signal data relating to signals received at the device from a plurality of electromagnetic signal sources, and the server comprising:
 a database of positioning data including electromagnetic signal source data for use by the positioning system;   a network connection for receiving signal data relating to signals received from a plurality of electromagnetic signal sources, and for transmitting position estimates;   a processor; and   computer program code for causing the processor, in use, to carry out the method of  claim 1 .   
     
     
         17 . A user positioning system comprising:
 a device, including a receiver for receiving at least one signal from a respective at least one electromagnetic signal source; and   a server, including a database of positioning data including electromagnetic signal source data for use by the positioning system;   wherein the device and the server are configured to carry out, between them, the method of  claim 1 .   
     
     
         18 . A non-transitory computer readable medium tangibly embodying computer program code for causing a computer to carry out a method as claimed in  claim 1 .