FINDING THE POSITION OF A MOBILE TERMINAL

• US 20110043406A1
• Filed: 01/15/2009
• Published: 02/24/2011
• Est. Priority Date: 03/10/2008
• Status: Active Grant

• Current Assignee: Cambridge Positioning Systems Limited (Qualcomm, Inc.)
• Original Assignee: Cambridge Positioning Systems Limited (Qualcomm, Inc.)
• Inventors: Duffett-Smith, Peter James, Rowe, Robert Willem, Jarvis, Murray Robert
• Granted Patent: US 8,730,105 B2
• Time in Patent Office: Days
• US Class Current: 342/387
• CPC Class Codes: G01S 19/46 the supplementary measurement being of a radio-wave signal type
• CPC Class Codes: G01S 5/0236 Assistance data, e.g. base station almanac
• CPC Class Codes: G01S 5/10 Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements , e.g. omega or decca systemsG01S5/12 takes precedence ; beacons and receivers cooperating therewith G01S1/306, G01S1/308
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A method and apparatus are disclosed for determining the position, or change in the position, of a mobile terminal. The terminal has a receiver for receiving the signals from one or more transmission sources at unknown positions and an independent positioning device able to find, when operative, the position of the mobile terminal. The method uses the independent positioning device to measure the position of the mobile terminal at one or more first locations. A respective first set of time or phase offset values of signals received from the transmission sources relative to each other or to a reference in the mobile terminal is measured in the mobile terminal, at each first location. A second set of time or phase offset values are measured in the mobile terminal at a second terminal location where the independent positioning device is not operative and a second set of time or phase offset values of the signals received from the transmission sources, relative to each other or to a reference in the mobile terminal is measured. The values and said first measured terminal position or positions are combined, to thereby calculate the position of the mobile terminal at the second location, or the change in position of the mobile terminal between a first location and the second location.

Claims

1. A method of determining the position, or change in the position, of a mobile terminal having a receiver for receiving the signals from one or more transmission sources at unknown positions, the mobile terminal also having an independent positioning device able to find, when operative, the position of the mobile terminal, the method comprising the steps of

using said independent positioning device, measuring the position of the mobile terminal at one or more first locations;

measuring in the mobile terminal, at each first location, a respective first set of time or phase offset values of signals received from the transmission sources relative to each other or to a reference in the mobile terminal;

measuring in the mobile terminal, at a second terminal location where said independent positioning device is not operative, a second set of time or phase offset values of the signals received from the transmission sources, relative to each other or to a reference in the mobile terminal; and

combining said values and said first measured terminal position or positions, and thereby calculating the position of the mobile terminal at the second location, or the change in position of the mobile terminal between a first location and the second location.

2. A method according to claim 1, the transmission sources are the base stations of a digital communications network.

3. A method according to claim 1, wherein the independent positioning device is a global navigation satellite system receiver.

4. A method according to claim 1, wherein the measuring of time or phase offset values of the signals received from the transmission sources is made with respect to a signal generated within the mobile terminal.

5. A method according to claim 1, wherein the measuring of time or phase offset values of signals received from the transmission sources is made with respect to the signal from one of the transmission sources.

6. A method according to claim 1, wherein the positions of the transmission sources themselves are also determined.

7. A method according to claim 6, further including creating in the mobile terminal a database of transmission-source positions.

8. A mobile communications terminal having

a receiver for receiving communications signals from transmission sources of a communications network;

an independent positioning device able to find, when operative, a position of the mobile terminal;

means for measuring sets of time or phase offset values of the communications signals received from the transmission sources relative to each other or to a reference in the mobile terminal;

means for combining the offset values measured at plural locations of the terminal with a terminal position or positions measured by the independent positioning device, and thereby calculating at a subsequent location, the position of the mobile terminal or the change in position of the mobile terminal between first and second locations.

9. A mobile communications terminal according to claim 8, wherein the receiver is a single-channel device able to switch between the signals radiated by the transmission sources.

10. A mobile communications terminal according to claim 8, wherein the receiver is a multi-channel device arranged to receive multiple communications signals in parallel.