Positioning of mobile wireless terminal

• US 20070035445A1
• Filed: 10/18/2006
• Published: 02/15/2007
• Est. Priority Date: 04/18/2002
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Yamada, Isamu, Ninomiya, Teruhisa
• Granted Patent: US 7,319,428 B2
• Time in Patent Office: Days
• US Class Current: 342/442
• CPC Class Codes: G01S 3/46 using antennas spaced apart and measuring phase or time difference between signals therefrom, i.e. path-difference systems
• CPC Class Codes: G01S 5/02 using radio waves using satellite radio beacon systems for determining position G01S19/00
• CPC Class Codes: G01S 5/08 Position of single direction-finder fixed by determining direction of a plurality of spaced sources of known location

Abstract

An apparatus for determining a position of a mobile wireless station comprises means for determining the position of the mobile wireless station in accordance with a position of a first reference wireless station, a position of a second reference wireless station, a first relative angular direction between the mobile wireless station and the first reference wireless station, and a second relative angular direction between the mobile wireless station and the second reference wireless station.

Claims

1. A wireless apparatus for determining a phase difference of a received RF signal, comprising:

first and second antennas displaced from each other by a predetermined distance for receiving an RF signal; and

an exclusive OR (EXOR) circuit comparing two binary signals derived from the received RF signal that are associated with said first and second antennas respectively, wherein an absolute phase difference is based on a pulse width of the comparison.

2. The apparatus according to claim 1, further comprising a detector for detecting source identification included in said received RF signal.

3. The apparatus according to claim 1, wherein the apparatus is operable in accordance with a Bluetooth standard.

4. A method for determining a phase difference based on received RF signals associated with first and second antennas respectively, comprising:

producing a plurality of binary signals based on the received RF signals; and

exclusive ORing at least two of the binary signals.

5. The method according to claim 4, wherein the producing the plurality of binary signals comprises:

latching a first signal at a rising edge of a second signal; and

comparing levels of the first and the second signals.