Pilot beacon system for indoor positioning

• US 9,354,293 B2
• Filed: 09/20/2012
• Issued: 05/31/2016
• Est. Priority Date: 10/03/2011
• Status: Active Grant

• Current Assignee: Westell Incorporated (Westell Technologies Incorporated)
• Original Assignee: Westell Incorporated (Westell Technologies Incorporated)
• Inventors: Crilly, William J. Jr., Ziegler, Philip
• Primary Examiner(s): Pham, Timothy
• Application Number:
  US13/623,133
• Publication Number:
  US 20130084886A1
• Time in Patent Office: 1,349 Days
• Field of Search: 455/456.1
• US Class Current: 1/1
• CPC Class Codes: G01S 1/20 using a comparison of transit time of synchronised signals transmitted from non-directional antennas or antenna systems spaced apart, i.e. path-difference systems
• CPC Class Codes: G01S 1/24 the synchronised signals being pulses or equivalent modulations on carrier waves and the transit times being compared by measuring the difference in arrival time of a significant part of the modulations , e.g. LORAN systems
• CPC Class Codes: G01S 5/0263 by combining or switching between positions derived from two or more separate positioning systems
• CPC Class Codes: H04W 4/33 for indoor environments, e.g. buildings
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

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.

Claims

1. A method for determining the location of a wireless handset in a building, comprising:

providing one or more pilot beacons transmitting a plurality of pseudo-random number (“

PN”

) codes with PN offsets, wherein the pilot beacons are located inside a building;

the PN codes of the one or more pilot beacons corresponding to PN codes associated with cellular base-stations having known locations located outside the building, and the PN offsets of the one or more pilot beacons selected to reflect the only the delay of a signal propagating from a corresponding cellular base station to a predetermined location within the building, and wherein the PN offsets are set early such that the handset will report the PN codes received from the pilot beacon rather than distant PN'"'"'s received from a macro network;

providing information regarding relative delays associated with one or more pilot beacon signals received by a wireless handset to a position determination entity (“

PDE”

) resulting in output fix files calculated on the basis of the relative delays associated with one or more pilot beacon signals received by a wireless handset;

determining from the PDE output fix files a position fix of the predetermined location within the building for use in locating a wireless handset in a building, and

wherein the plurality of pseudo-random number (“

PN”

) codes with PN offsets broadcast by the one or more pilot beacons is sufficient to fix a position of a wireless handset without a contribution from any physical base station.

2. The method for determining the location of a wireless handset in a building of claim 1, wherein the step of modifying the PN offsets of the pilot beacons comprises adjusting the power level.

3. The method for determining the location of a wireless handset in a building of claim 1, wherein the step of modifying the PN offsets of the pilot beacons comprises adjusting the amplitude.

4. The method for determining the location of a wireless handset in a building of claim 1, wherein the step of modifying the PN offsets of the pilot beacons comprises adjusting the time modulation.

5. The method for determining the location of a wireless handset in a building of claim 1, wherein the PDE output fix file comprises x-y coordinate information.

6. The method for determining the location of a wireless handset in a building of claim 1, further comprising providing a wireless handset configured to receive and to transmit information for use by the PDE in locating a wireless handset in a building.

7. The method for determining the location of a wireless handset in a building of claim 1, further comprising providing a macro network comprising a plurality of PN codes with PN offsets and associated location information.

8. The method of claim 1, further comprising the step of estimating a z-axis position of a handset on the basis of the relative amplitude of signals received at a handset from the one or more pilot beacons.

9. The method of claim 1, wherein the step of determining from the PDE output fix files a position fix of the predetermined location within the building for use in locating a wireless handset in a building does not require modification to a preexisting base station almanac.

10. The method of claim 1, further comprising providing a plurality of pilot beacons each having a location within the building, wherein each pilot beacon broadcasts PN offsets of the one or more pilot beacon, which, when provided to a PDE, create a position solution fixing the location of a wireless handset within a predetermined zone at the location of a given pilot beacon.