Locating electromagnetic signal sources

Abstract

There is disclosed a method of estimating the location of a plurality of electromagnetic signal sources, comprising: scanning at a first plurality of locations to generate signal source position data, the signal source position data representing estimates of the position of at least one of said signal sources; scanning at a second plurality of locations using a signal detection system to generate signal detection data, the signal detection data relating to signals received at the second plurality of locations from the signal sources; processing the signal source position data in dependence on the signal detection data to correct estimation errors in the signal source position data; and outputting the processed signal source position data.

What is claimed is: 
     
         1 . A method of estimating the location of a plurality of electromagnetic signal sources, comprising:
 scanning at a first plurality of locations to generate signal source position data, the signal source position data representing estimates of the position of one or more said signal sources;   scanning at a second plurality of locations using a signal detection system to generate signal detection data, the signal detection data relating to signals received at the second plurality of locations from the signal sources;   processing the signal source position data in dependence on the signal detection data to correct estimation errors in the signal source position data; and   outputting the processed signal source position data.   
     
     
         2 . A method according to  claim 1 , wherein processing the signal source position data further comprises using the signal detection data to estimate the position of the second plurality of locations. 
     
     
         3 . A method according to  claim 1 , further comprising receiving location information data representing information about the second plurality of locations, and wherein processing the signal source position data further comprises using the location information data to estimate the position of the second plurality of locations. 
     
     
         4 . A method according to  claim 3 , wherein the location information data comprises a user estimate of the position of at least one of said second plurality of locations. 
     
     
         5 . A method according to  claim 4 , further comprising inputting the location information data via a user input device. 
     
     
         6 . A method according to  claim 1 , wherein processing the signal source position data further comprises processing the signal detection data in accordance with an environmental model representing environmental factors applying to the signal sources. 
     
     
         7 . A method according to  claim 6 , further comprising receiving at least one of environmental model selection data representing a choice of environmental model and environmental model parameter data representing a choice of at least one parameter of the environmental model, and processing the signal detection data in accordance with said at least one of the environmental model selection data and the environmental model parameter data. 
     
     
         8 . A method according to  claim 7 , further comprising inputting said at least one of environmental model selection data and environmental model parameter data via a user input device. 
     
     
         9 . A method according to  claim 1 , wherein processing the signal source position data further comprises generating further signal source position data representing new estimates of the signal sources in dependence on the signal detection data. 
     
     
         10 . A method according to  claim 9 , further comprising processing the signal source position data and the further signal source position data to determine an appropriate adjustment to the signal source position data. 
     
     
         11 . A method according to  claim 1 , further comprising processing the signal detection data to estimate the location of additional signal sources that were not detected at the first plurality of locations, and adding additional signal source position data to the signal source position data. 
     
     
         12 . A method according to  claim 1 , wherein scanning at the first plurality of locations comprises:
 scanning at the first plurality of locations to generate initial signal detection data, the initial signal detection data relating to signals received at the first plurality of locations from the signal sources;   processing the initial signal detection data in dependence on first scanning position data, the first scanning position data representing the position of each of the first plurality of locations, in order to generate the position estimate data.   
     
     
         13 . A method according to  claim 12 , wherein scanning at the first plurality of locations comprises using the signal detection system to generate the initial signal detection data. 
     
     
         14 . A method according to  claim 1 , further comprising using a positioning system at each of the first plurality of locations to generate the first scanning position data. 
     
     
         15 . A method according to  claim 14 , wherein the positioning system is generally more effective at the first plurality of locations than at the second plurality of locations. 
     
     
         16 . A method according to  claim 14 , wherein the signal detection system is generally more effective at the second plurality of locations than at the first plurality of locations. 
     
     
         17 . A method according to  claim 1 , further comprising scanning using a signal detection system at a further plurality of locations to generate further signal detection data, and further processing the signal source position data in dependence on the further signal detection data. 
     
     
         18 . A method according to  claim 1 , further comprising processing the signal source position data to generate map data representing a map of the signal sources. 
     
     
         19 . A method according to  claim 1 , wherein the signal source is a wireless access point, such as a base station in a wireless communications network. 
     
     
         20 . A method according to  claim 19 , in which at least one of the signal detection data, the signal source position data and the processed signal source position data is transmitted via the wireless access point.