System and method for synchronizing base stations

• US 7,565,147 B2
• Filed: 01/25/2005
• Issued: 07/21/2009
• Est. Priority Date: 01/27/2004
• Status: Expired due to Fees

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Simons, Paul R., Wilcox, Martin S.
• Primary Examiner(s): Kincaid; Lester
• Assistant Examiner(s): Jama; Isaak R
• Application Number:
  US10/587,721
• Publication Number:
  US 20070167169A1
• Time in Patent Office: 1,638 Days
• Field of Search: 455/456.2, 455/446, 342/445, 342/437, 342/380, 342/357.1, 370/332
• US Class Current: 455/446
• CPC Class Codes: G01S 5/0205 Details
• CPC Class Codes: G01S 5/0289 of multiple transceivers, e.g. in ad hoc networks
• CPC Class Codes: G01S 5/06 Position of source determined by co-ordinating a plurality of position lines defined by path-difference measurements G01S5/12 takes precedence
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

The invention provides a method for installing a positioning system, the positioning system comprising two or more base stations (BS1 to BS4), and comprises the steps of; collocating the base stations (BS1 to BS4); quantifying any lack of synchronization between the clocks of the base stations; relocating one or more of the base stations (BS2′ to BS4′) to their fixed, operational positions and measuring the time of flight of a signal from each of the relocated base stations; determining from the time of flight and quantified lack of synchronization data the relative separation of the base stations (BS1, BS2′ to BS4′) and hence the configuration of the installed positioning system, and recording the configuration of the installed positioning system. Data defining the configuration of the system can be relayed to a mobile transceiver in the vicinity of the installed positioning system and, along with time of flight measurements of signals emitted by the individual base stations, and data quantifying any real time lack of synchronization of the clocks of the base stations, can be used by the transceiver to position itself within the geographical area defined by the positioning system.

Claims

1. A method for installing a positioning system, the positioning system comprising two or more base stations the method comprising the steps of:

(a) prior to positioning the two or more base stations to their operational positions within a selected environment, symmetrically docking together said two or more base stations at a single symmetrically docketed position,

(b) quantifying and recording clock offset information between each of said two or more docked base stations with respect to a center reference base station at said single docked position,

(c) relocating one or more of the base stations from said single docketed position to their fixed, operational positions,

(d) measuring the time of flight of a signal from each of the relocated base stations to at least one other base station,

(e) determining, at said center reference base station from the recorded clock offset information time of flight and the quantified and recorded clock offset a relative separation of the base stations and hence the configuration of the installed positioning system,

(f) recording at said center reference base station the configuration of the installed positioning system, and

(g) storing the configuration data at each base station.

2. A method as claimed in claim 1 wherein after the quantifying step, and before the relocating step, the clocks of the base stations are synchronised.

3. A positioning system comprising:

a plurality of base stations,

means for symmetrically docking together said plurality of base stations at a single symmetrically docketed position,

means for quantifying and recording by a center reference base station at said single docked position clock offset information between the respective clocks of the plurality of base stations with respect to the center reference base station,

means for relocating one or more of the base stations from said single docketed position to their fixed, operational positions,

means for measuring the time of flight of a signal from each of the relocated base stations to at least one other base station,

means for determining, at said center reference base station, from the measured time of flight information and the clock offset information, a relative separation of the base stations and hence the configuration of the installed positioning system,

means for recording at said center reference base station the configuration of the installed positioning system, and

means for storing the configuration data at each base station.

4. A positioning system as claimed in claim 3 including a base station operable as a location measurement unit for E-OTD positioning.

5. A positioning system as claimed in claim 3 comprising 3 or more base stations.

6. A positioning system as claimed in claim 3 comprising 5 or more base stations.

7. A positioning system as claimed in claim 3 comprising 7 or more base stations.

8. A positioning system as claimed in claim 3 wherein the base stations are removably dockable to each other.

9. A positioning system as claimed in claim 8 wherein the remaining base stations are symmetrically, removably dockable about the reference base station.

10. A positioning system as claimed in claim 3 wherein the means for quantifying and means for recording are embodied in the reference base station.

11. A center base station configured to perform the method of:

a) prior to positioning a plurality of base stations to their operational positions within a selected environment;

b) quantifying and recording, at the center base station, clock offsets between a plurality of docked base stations relative to the center base station at a single docked position;

c) one of

(i) relocating one or more of the plurality of base stations. from the single docked position to their operational positions and measuring at the center base station, the time of flight signal from each of the relocated base stations to at least one other base station;

or

(ii)measuring at the center base station, the time of flight signal from each of the relocated base stations to at least one other base station and relocating one or more of the plurality of base stations, from the single docked position to their operational positions

d) determining, at the center base station, from the quantified and recorded clock offsets and the measured time of flight signals, a relative separation of the base stations and hence a configuration of an installed positioning system; and

e) recording at the center base station, the configuration of the installed positioning system.