Pilot beacon system for indoor positioning

Abstract

The system and method uses a one or more pilot beacons to more accurately locate the position of an indoor mobile device. Modulation and level control of the co-pilot beacons provides a third dimension, z-axis, of positioning. An augmented Position Determining Entity (“aPDE”) can be used which does not modify the existing PDE in the network, and facilitates and ensures high-integrity information during a 2D to 3D positioning upgrade.

What is claimed: 
     
         1 . A method for determining the location of a wireless handset in a building, comprising:
 providing one or more pilot beacons comprising pseudo-random number (“PN”) codes with PN offsets and associated location information, wherein the pilot beacons are located inside a building;   providing a macro network comprising a plurality of PN codes with PN offsets and associated location information;   providing an existing Position Determination Entity (“PDE”) comprising output fix files;   providing an augmented PDE comprising output fix files;   determining the Horizontal Estimated Position Error (“HEPE”) of the existing PDE output fix file;   determining the HEPE of the augmented PDE output fix file;   comparing the HEPE from the existing PDE output fix file with the HEPE from the augmented PDE output fix file; and   determining whether the HEPE from the augmented PDE output fix file should be used as the position fix for use in locating a wireless handset in a building.   
     
     
         2 . The method for determining the location of a wireless handset in a building of  claim 1 , further comprising the step of modifying the PN offsets of the pilot beacons. 
     
     
         3 . The method for determining the location of a wireless handset in a building of  claim 2 , wherein the step of modifying comprises adjusting the power level. 
     
     
         4 . The method for determining the location of a wireless handset in a building of  claim 2 , wherein the step of modifying comprises adjusting the amplitude. 
     
     
         5 . The method for determining the location of a wireless handset in a building of  claim 2 , wherein the step of modifying comprises adjusting the time modulation. 
     
     
         6 . The method for determining the location of a wireless handset in a building of  claim 1 , wherein the existing PDE output fix file comprises x-y coordinate information.